100 GHz Reflectometer for Sensitivity Analysis of MEMS Sensors Comprising an Intermediate Frequency Six-port Receiver - Linz, Sarah; Oesterle, Florian; Talai, Armin; Lindner, Stefan; Mann, Sebastian; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks, 2015)
Due to the growing market for Micro Electro Mechanical Systems (MEMS), especially for the application in mobile electronic devices like cameras, phones or tablet computers, cost and time efficient test and evaluation systems are required for the production process. This work presents a novel measurement setup for MEMS microphones, that allows an inline, contactless evaluation of the microphones' mechanical sensitivity at an early stage of the manufacturing process. A heterodyne receiver with a Six-port demodulator is deployed for displacement detection with micrometer resolution. Since the Six-port demodulator allows very high sampling rates only limited by the analog-to-digital converter, short measurement times can be achieved.
elib2cris::1512001600,linz2015
Keywords: MEMS; Six-Port; Microwave Interferometer; W-band; Contactless Testing; Pull-in; Mechanical Sensitivity

122 GHz Low-cost Substrate Integrated Waveguide based Leaky-Wave Antenna Design - Frank, Martin; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (2019 IEEE Radio and Wireless Symposium (RWS), 2019)

1.37A,2A current regulating high side driver with 0.4μJ energy limitation in unpowered state - Easwaran, Sri Navaneeth; Weigel, Robert (Proceedings of the 2020 IEEE Dallas Circuits and Systems Conference, DCAS 2020, 2020)
Squib Driver Unit deploys the airbag for passenger safety by igniting the squibs. The High Side (HS) driver provides regulated current for defined dwell times in order to ignite the squib with energy of 8mJ. This energy should be delivered only when the driver is powered. However dynamic shorts with slew rates of 100V/μs on the drain of the HS driver in its unpowered state can also provide 8mJ energy to the squib and inadvertently deploy the airbag if proper gate discharge is not present to ensure fast turn OFF of the HS driver. The HS driver proposed here regulates the current to 1.37A for 2.1ms and 2A for 0.75ms in the powered state with 0.4μJ energy limitation to prevent inadvertent deployment using passive and active discharge paths in the unpowered state. The leakage current from the drain of HS driver is 1μA at 35V when compared to prior Art of 50μA. This design is implemented and verified on a 4 loop squib driver in 0.35μm, 85V BiCMOS process.
CRIS-Team Scopus Importer:2021-04-19
Keywords: Current regulation; Energy limit; High Side Driver; Unpowered state

17 GHz receiver in TSLP package for WLAN/ISM applications in 0.13 μm CMOS - Kienmayer, C.; Engl, Mario; Desch, A.; Thüringer, R.; Berry, M.; Tiebot, M.; Scholtz, Arpad; Weigel, Robert (Proceedings of the 31st European Solid-State Circuits Conference, 2005)
This work presents a fully integrated CMOS receiver in a leadless plastic package (TSLP) for high data rate WLAN applications at 17.2 GHz ISM band. The receiver offers a gain of 35 dB, input 1dB compression point of -49.6 dBm, SSB noise figure of 9.9 dB and an input IP3 of -39.8 dBm. At a power supply of 1.5 V, the receiver, which includes LNA, complex demodulator, VCO, IQ-divider and all RF-buffers, consumes only 245 mW.
elib2cris::1512001600,kienmayer2005
Keywords: Receiver; TSLP

1mm Coaxial Matches with an Excellent Absorption Behavior over the Frequency Range 0 - 110 GHz - Tag, Andreas; Leinhos, Jens; Hechtfischer, Gerd; Leibfritz, Martin; Eibert, Thomas (European Microwave Conference, 2013)
Combining a theory for reflection free termination of coaxial lines together with a novel manufacturing method results in coaxial 1-mm matches with an excellent absorption behavior over the frequency range from 0 to 110 GHz. Three different electromagnetic simulation approaches verify the capability of these matches to achieve smaller reflection coefficients than -43 dB over the whole frequency range and matches with a maximum reflection coefficient of only -32 dB have been produced.
elib2cris::1512001600,tag2013

24 GHz Six-Port Medical Radar for Contactless Respiration Detection and Heartbeat Monitoring - Vinci, Gabor; Lindner, Stefan; Barbon, Francesco; Hofmann, Maximilian; Fischer, Georg; Kissinger, Dietmar; Kölpin, Alexander (9th European Radar Conference, 2012)
For numerous medical applications it is of primary interest to monitor the breath rate and heartbeat of a patient over time. Especially important is to observe the respiration of a patient over night to detect potential sleep disorders. Furthermore, heartbeat frequency is also a precious informationwhich can help to improve diverse diagnosis procedures. In orderto better analyze these vital parameters an innovative contactlessrespiration detection and heartbeat monitoring technique hasbeen developed. This novel method is based on the six-portinterferometric radar and is capable of detecting breath rateas well as heartbeat frequency without applying sensors orelectrodes on the patients body.
elib2cris::1512001600,vinci2012f
Keywords: Six-Port; Bioradar; Vital Sign Monitoring; Heartbeat Detection; Respiration Detection

27 Gb/s PRBS Generator with In-Operation Programmable Taps for PMCW Radar - Probst, Florian; Engelmann, Andre; Weigel, Robert (2024 IEEE 24th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF), 2024)

2D-FEM Modeling of Mirror-Type FBARs based on an Adapted Set of Material Parameters - Link, Andreas; Schmidhammer, Edgar; Mayer, Markus; Bader, Bernhard; Wagner, Karl Christian; Weigel, Robert (Proceedings of the IEEE International Ultrasonics Symposium, 2006)
elib2cris::1512001600,link2006a

30 % Frequency-Tuning-Range 60 GHz Push-Push VCO in 28 nm Bulk CMOS Technology - Rimmelspacher, Johannes; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (Radio & Wireless Week 2018, 2018)
This paper presents a 60 GHz push-push crosscoupled voltage-controlled oscillator (VCO) in 28 nm bulk CMOS technology. It achieves a continuous frequency tuning range (FTR) of 30% from 52 to 71 GHz in a single sweep. We propose coupling the fundamental harmonic from the VCO core by means of magnetic coupling via a transformer-based resonant tank. This is used instead of directly connecting the output buffers to the oscillation node. The VCO provides a phase noise in the range of -93 to -82 dBc/Hz at 1 MHz offset from carrier across the entire FTR. The measured DC power dissipation including buffers at the fundamental and second harmonic outputs does not exceed 68 mW. The circuit operates from a single supply of 0.9 V. The circuit area excluding pads is 0.15 mm2. Thanks to the achieved very wide continuous FTR, the presented VCO is suitable for FMCW radar applications that require a very fine range resolutio

36 % Frequency-Tuning-Range Dual-Core 60 GHz Push-Push VCO in 45 nm RF-SOI CMOS Technology - Rimmelspacher, Johannes; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (IEEE MTT-S International Microwave Symposium 2017, 2017)
This paper presents a millimeter-wave (mm-wave) push-push voltage-controlled oscillator (VCO) in a 45 nm RFSOI CMOS technology. The circuit aims to meet specifications for FMCW radar applications requiring an ultra-wide PLL modulation bandwidth. The fundamental output of the VCO can be tuned from 27 GHz to 39 GHz, which corresponds to frequency tuning range (FTR) of 36 %. We extract the 2nd harmonic in a non-invasive way using a transformer. The measured phase noise (PN) at 1 MHz offset from the fundamental carrier varies across the tuning range from -100 dBc/Hz to -90 dBc/Hz. The VCO including output buffers dissipates 65 mW DC power from a single 1 V supply and consumes a chip area of 0.12 mm2.
Keywords: millimeter-wave; ultra-wideband; CMOS technology; cutoff frequency; System-on-Chip; Silicon-on-Insulator

3A Fault Tolerant Low Side Driver Circuit Design Using Design FMEA for Automotive Applications - Easwaran, Sri Navaneeth; Mollat, Martin; Sreedharan, Deepak; Camdzic, Samir; Kashvap, Sunil Venugopal; Weigel, Robert (17th IEEE International New Circuits and Systems Conference, NEWCAS 2019, 2019)
Electronic component is increasing in Automotive applications spanning from power train, connectivity, airbag, driver assistance, braking and more. Most of these components are Integrated Circuits that have to fulfill system safety requirements in sophisticated safety applications. A functional safety review and assessment are used to confirm whether integrated circuit component fulfills hardware safety and functional requirements derived from system safety goals. One such automotive safety system is the Airbag Control Unit with integrated Squib Drivers that deploys driver and passenger airbags when a valid car crash event is detected. Airbags are passive safety application, critical for driver and passenger safety that can be fatal if not deployed properly. Therefore, components used in airbag applications have to fulfill the highest system Automotive Safety Integrity Level (ASIL), ASIL-D. The safety critical part of Squib Driver Integrated Circuits is the High Side and Low Side powerFETs with its pre-drivers, control, monitoring, protection and diagnostics. This paper describes design Failure Mode Effect Analysis (FMEA) as one part of the systematic design methodology flow by using the low side current regulating driver as an example. This systematic approach resulted in a unique safety architecture that prevents inadvertent activation of the low side powerFET in the unpowered state of the driver. In the powered state, the current is regulated to 3A and is stable for inductances up to 3mH, a 30x higher inductive load than a traditional squib driver.
CRIS-Team Scopus Importer:2020-02-21
Keywords: current regulation; Design FMEA; Functional Safety; Low Side Drivers; methodology; stability; unpowered state

3D-Accuracy Improvements for TDoA Based Wireless Local Positioning Systems - Eickhoff, Ralf; Ellinger, Frank; Mosshammer, Ralf; Weigel, Robert; Ziroff, Andreas; Huemer, Mario (IEEE GLOBECOM Workshops, 2008 (WMSN), 2008)
Local positioning systems significantly enhance the value of wireless sensor networks (WSN). This paper gives an overview of local positioning system topologies for WSNs of the European project RESOLUTION, which operate in the unlicensed ISM band at 5.8 GHz with 150 MHz bandwidth and allowed 25 mW effective isotropic radiated transmit power. The achievable 3D-localization accuracy is analyzed with respect to the performance of the designed hardware components and the indoor environment. It is further shown that accuracy as a primary attribute of local positioning systems also affects secondary quality-of-service (QoS) features such as update-rates or latency. This investigation allows an optimization of both attributes simultaneously, primary and secondary QoS aspects.
elib2cris::1512001600,eickhoff2008

3D Printed Slotted Waveguide Array Antenna for Automotive Radar Applications in W-Band - Lomakin, Konstantin; Simon, D.; Sippel, Mark; Gold, Gerald; Helmreich, Klaus; Seler, Ernst; Tong, Z.; Reuter, R. (48th European Microwave Conference (EuMW 2018), 2018)

3D rectangular waveguide integrated in embedded Wafer Level Ball Grid Array (eWLB) package - Seler, Ernst; Wojnowski, M.; Hartner, W.; Bock, J.; Lachner, R.; Weigel, Robert; Hagelauer, Amelie Marietta (Proceedings - Electronic Components and Technology Conference, 2014)
In this paper, we present for the first time the realization of a 3D rectangular waveguide in the fan-out area of an embedded Wafer Level Ball Grid Array (eWLB) Package using laminate inserts. To obtain the waveguide side walls in eWLB, a RF laminate with micro-vias is inserted in the fan-out area. The classical redistribution layer (RDL) on the one surface and an additional back side metallization on the other surface of the package are used to realize the top and bottom walls of the waveguide. Furthermore, we focus on a single-ended coplanar waveguide (CPW) to rectangular waveguide transition. We investigate and compare two concepts for the transformation of the transverse electromagnetic (TEM) mode of a CPW to the transverse electric (TE) mode of a rectangular waveguide. The first concept is using a via in the waveguide structure to excite the waveguide TE mode. The second concept is a planar realization using a modified shape of the RDL to realize the mode transformation. We show by the means of measurements the characteristics of each version. We show that the mode change is done with almost no additional losses to those related to physical length of the transmission line. Furthermore we present several on-wafer measurements which agree very well with the RF behavior predicted by the simulations. This 3D waveguide integration in eWLB enables the realization of many new RF features in chip embedding technologies in the future.
CRIS-Team Scopus Importer:2023-03-08

3D surface reconstruction for laparoscopic computer-assisted interventions: Comparison of state-of-the-art methods - Groch, A.; Seitel, A.; Hempel, Sarah-Marie; Speidel, S.; Engelbrecht, Rainer; Penne, Jochen; Höller, Kurt Emmerich; Röhl, S.; Yung, K.; Bodenstedt, S.; Pflaum, Felix; Dos Santos, T. R.; et al. (Medical Imaging 2011: Visualization, Image-Guided Procedures, and Modeling, 2011)
One of the main challenges related to computer-assisted laparoscopic surgery is the accurate registration of pre-operative planning images with patient's anatomy. One popular approach for achieving this involves intraoperative 3D reconstruction of the target organ's surface with methods based on multiple view geometry. The latter, however, require robust and fast algorithms for establishing correspondences between multiple images of the same scene. Recently, the first endoscope based on Time-of-Flight (ToF) camera technique was introduced. It generates dense range images with high update rates by continuously measuring the run-time of intensity modulated light. While this approach yielded promising results in initial experiments, the endoscopic ToF camera has not yet been evaluated in the context of related work. The aim of this paper was therefore to compare its performance with different state-of-the-art surface reconstruction methods on identical objects. For this purpose, surface data from a set of porcine organs as well as organ phantoms was acquired with four different cameras: a novel Time-of-Flight (ToF) endoscope, a standard ToF camera, a stereoscope, and a High Definition Television (HDTV) endoscope. The resulting reconstructed partial organ surfaces were then compared to corresponding ground truth shapes extracted from computed tomography (CT) data using a set of local and global distance metrics. The evaluation suggests that the ToF technique has high potential as means for intraoperative endoscopic surface registration. © 2011 SPIE.

3D-TLM analysis of high-Tc superconducting coupled-coplanar waveguide - Vanselow, Martin; Isele, Bertram; Weigel, Robert; Russer, Peter (IEEE International Symposium on Antennas and Propagation, 1992, 1992)
Summary form only given. The authors discuss the application of the three-dimensional transmission-line matrix (3D-TLM) method to coupled coplanar waveguide (CCPW)-circuit structures. The 3-D-TLM algorithm with the symmetrical condensed TLM node is used. The circuits are investigated in the time domain by calculating the response for single-pulse excitation. From these results, the frequency characteristics are calculated by fast Fourier transform using zero-padding. The circuit structures are embedded in domains bounded by absorbing walls. The absorbing boundary conditions are modeled by discrete Green's functions. The authors describe the surface impedance of the high-T/sub c/ superconducting material according to the two-fluid model and to the London theory by inductive and resistive stubs.<>
elib2cris::1512001600,vanselow1992a
Keywords: high-temperature superconductors; Coupling circuits; Coplanar waveguides; inductive stubs; symmetrical condensed TLM node; Fast Fourier transforms; resistive stubs; strip lines

3D-TLM-Modeling of Bi-Quadratic Coplanar Waveguide Taper for Picosecong Applications - Weigel, Robert; Isele, Bertram; Stöckeler, F.; Thomann, Wolfgang; Russer, Peter (Proc. XXIVth URSI General Assembly, 1993)
elib2cris::1512001600,weigel1993

450 MHz for Smart Metering & Smart Grid - Elhaddad, Ahmed; Irnstorfer, Florian; Fischer, Georg (21. ITG/GMA Fachtagung Sensoren und Messsysteme 2022, 2022)
450 MHz for Smart Metering & Smart Grid<br
Keywords: Cellular IoT; 450 MHz; Smart Grid; Smart Metering; Antenna Detuning; PAE

4D-2 High Volume Production of a Fully Matched 5050 PCS-CDMA-BAW Duplexer - Schmidhammer, Edgar; Heinze, Habbo; Schmiedgen, Monika; Mayer, Markus; Link, Andreas (IEEE Ultrasonics Symposium 2006., 2006)
Since 2001 bulk acoustic wave (BAW) technology is highly investigated due to its silicon-based technology for further integration in the RF part of e.g. mobile phones. At the IEEE UFFC Symposium 2005 in Rotterdam EPCOS presented the very first results of several CDMA related components like 3838 PCS BAW duplexer, full-band Tx-filter and Rx diversity filter using the solidly mounted resonator (SMR) technique and packaged using EPCOS' proprietary CSSPlus technology [Schmidhammer, E, et al.]. Meanwhile we have successfully started the high-volume production of a fully matched 5050 PCS BAW Duplexer, a component, which was requested by various customers. This BAW duplexer has been specifically designed to match the impedance network commonly employed at the PA output path, transforming the PA output impedance level of approx. 3 Omega into the 50 Omega reference level. Qualification tests according to JEDEC and IEC standards show a high reliability of the component with respect to temperature-shocks (-40deg/125deg), damp heat steady state tests (85 degC/85% relative humidity) and high temperature storage (125 degC). These quality levels were mainly achieved by employing a newly developed Ni-based UBM. The presented results show clearly our continuing improvements within SMR-BAW technology. Our process flow using a 200 mm manufacturing line uses only the minimum number of process steps by still keeping a high yield in combination with high process stability and high process robustness. EPCOS is the first component supplier worldwide deploying high-volume production based on 200 mm wafers.
elib2cris::1512001600,schmidhammer2006
Keywords: BAW; 200 mm-wafer; Duplexer; PCS; JEDEC; IEC

5G mm-Wave Stacked Class AB Power Amplifier in 45 nm PD-SOI CMOS - Ciocoveanu, Radu; Weigel, Robert; Hagelauer, Amelie Marietta; Geiselbrechtinger, Angelika; Issakov, Vadim (5G mm-Wave Stacked Class AB Power Amplifier in 45 nm PD-SOI CMOS, 2018)
This paper presents a single-stage stacked Class AB power amplifier (PA) with lower complexity for fifth generation (5G) K/Ka band front-ends that has been realized in a 45nm PDSOI CMOS technology. Measurement results show that the power amplifier achieves a saturated output power (Psat) of 17.3 dBm with a 39.7% maximum power-added efficiency (PAEmax) at 24 GHz. The output-referred 1-dB compression point (OP1dB) is 14.3dBm and the saturated output power varies from 15.9dBm to 17.3dBm for a frequency range from 22 GHz to 28 GHz. Furthermore, the circuit draws 40mA from a 2.9V supply and the chip core size is 0.35mm x 0.25 m
Keywords: Stacked PA; 45nm PD-SOI; 5G; High Power; High Efficiency

60 GHz industrial radar systems in silicon-germanium technology - Agethen, Roman; Pour Mousavi, Seyed Mehran; Forstner, Hans-Peter; Wojnowski, Maciej; Pressel, Klaus; Weigel, Robert; Kissinger, Dietmar (IEEE MTT-S international Microwave Symposium, 2013)
elib2cris::1512001600,agethen2013

60 GHz Tail-Node-Coupled Multi-Core Push-Push VCOs in 22 nm FD SOI CMOS Technology - Rimmelspacher, Johannes; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (European Microwave Conference 2018, 2018)
This paper proposes a compact realization of a phase-noise (PN) improving core-coupling technique for millimetre-wave (mm-Wave) CMOS LC voltage-controlled oscillators (VCOs). The target is to provide a multi-core wideband continuous frequency-tuning-range (FTR) and low PN for FMCW radar applications while maintaining area and complexity at a minimum level. The VCO cores are superharmonic injection-locked at second harmonic (H2) on a common tail node. Three VCOs are fabricated in a 22 nm fully depleted (FD) silicon-on-insulator (SOI) CMOS technology: Single-Core, Dual-Core and Quad-Core. All implementations have the same core design. Measurements show the expected PN improvement for the multi-core VCOs compared to the single-core VC

61 GHz Millimeter Wave Voltage Variable Attenuator Based on Flip-Chip Mounted PIN-Diodes - Mann, Sebastian; Lurz, Fabian; Lindner, Stefan; Barbon, Francesco; Linz, Sarah; Weigel, Robert; Kölpin, Alexander (20th International Conference on Microwaves, Radar, and Wireless Communications, 2014)
Voltage Variable Attenuators play a major role in radio frequency system design. In this paper, a voltage variable attenuator concept suitable for the 61GHz ISM band is introduced and discussed. The proposed reflection type voltage variable attenuator has a maximum attenuation of 32 dB in the 61 GHz ISM-band range, and a low phase-shift of less than 10° for low and medium attenuation values. Furthermore, a bias network is presented featuring low reflection loss, and robustness against manufacturing tolerances. For verification purposes, a voltage variable attenuator as well as a reference transmission line have been fabricated and measured.
elib2cris::1512001600,mann2014b
Keywords: 61 GHz; attenuator; bias network; p-i-n diode; reflection type; variable attenuator

61 GHz Six-Port Radar Frontend for High Accuracy Range Detection Applications - Mann, Sebastian; Vinci, Gabor; Lindner, Stefan; Linz, Sarah; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, 2013)
Abstract — Range detection is an challenging task, especially if high accuracy has to be reached. The hereby proposed 61GHz continuous wave radar system is based on a phase detector using Six-Port technique. For accuracy enhancement an improved isolation radar coupler has been introduced for broadband frequency modulated continuous wave radar as well as narrow band radar techniques. Furthermore, a Six-Port network based on four hybrid couplers is presented. Finally, the most important system subcomponents have been validated by measurements.
elib2cris::1512001600,mann2013a
Keywords: Six-Port; Radar Coupler

77-GHz Automotive Radar System based on SiGe - Integrated Circuits: Current Developments and Future Trends (Invited Paper) - Kissinger, Dietmar; Starzer, Florian; Wagner, Christoph; Knapp, Herbert; Forstner, Hans-Peter; Jäger, Herbert; Maurer, Linus; Lachner, Rudolf; Weigel, Robert (Fifth Joint Symposium on Opto- and Micorelectronics Devices and Circuits, 2009)
elib2cris::1512001600,kissinger2009a

8 Channel MIMO Long Range Radar Concept for Angular Estimation in Multi Target Scenarios - Lutz, Steffen; Erhart, Christian; Walter, Thomas; Weigel, Robert (IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), 2015)
In this contribution a novel concept for a lens based 8 channel MIMO radar is presented. Hereby the sensor concept deals with a combination of optical beamforming based on a dielectric lens and the classical MIMO radar approach to increase the angular resolution. The sensor architecture is presented, the antenna concept introduced and characterized by measurements. After a brief formulation of the signal model, the evaluation of the angular performance based on the Cramer-Rao lower bound is introduced. The paper concludes with the comparison between MIMO and MISO radar processing in real world multiple target scenarios.
elib2cris::1512001600,lutz2015

A 0.039 mm2 Inverter-Based 1.82 mW 68.6 dB-SNDR 10 MHz-BW CT-Sigma Delta-ADC in 65 nm CMOS - Zeller, Christian; Muenker, Christian; Weigel, Robert (39th European Solid State Circuits Conference, 2013)
elib2cris::1512001600,zeller2013

A 0.039 mm2 Inverter-Based 1.82 mW 68.6 dB-SNDR 10 MHz-BW CT-Sigma Delta-ADC in 65 nm CMOS Using Power- and Area-Efficient Design Techniques - Zeller, Sebastian; Muenker, Christian; Weigel, Robert; Ußmüller, Thomas (IEEE Journal of Solid-State Circuits, 2014)
elib2cris::1512001600,zeller2014

A 0.13μm 1.5V CMOS I/Q Downconverter with Digital Adaptive IIP2 Calibration - Dufrene, Krzysztof; Boos, Zdravko; Weigel, Robert (IEEE International Solid-State Circuits Conference, 2007)
A low-voltage I/Q downconverter with digital adaptive IIP2 calibration is presented. The system maintains high linearity over time by continuously updating tuning codes in response to varying operating conditions. A prototype is fabricated in a 0.13μm RF CMOS process. At 2GHz LO, it draws 48mA from a 1.5V supply
elib2cris::1512001600,dufrene2007

A 10 Gb/s Highly-Integrated Adaptive Pseudo-Noise Transmitter for Biomedical Applications - Schmidt, Christian; Nehring, Johannes; Dietz, Marco; Weigel, Robert; Kissinger, Dietmar; Hagelauer, Amelie Marietta (IEEE Radio and Wireless Symposium, 2017)
A highly-integrated (2^11)-1 pseudo-random bit sequence (PRBS) transmitter for biomedical applications is presented. The chip consists of an ultra-wideband synthesizer with an integrated divider to drive a PLL, a linear feedback shift register (LFSR) to generate an M-sequence and a programmable binary divider to enable adaptive subsampling technique in the signal processing path. The circuit is created to be used in a miniaturized portable PRBS based sensor system for biomedical applications. A conceivable application is the measurement of dehydration in a human body. The PRBS generator is capable of generating a bit-rate up to 10 Gb/s, correlating to a maximum bandwidth of the generated sequence of 5 GHz, which is sufficient for the designated applications. The circuit is manufactured in an 0.35 um SiGe-Bipolar technology with an ft of 200 GHz using 12 mm^2 chip area.
elib2cris::1512001600,schmidt2017

A 10 GHz Low-Power Multi-Modulus Frequency Divider using Extended True Single-Phase Clock (E-TSPC) Logic - Jung, Melanie; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (The European Microwave Integrated Circuits Conference, 2012)
elib2cris::1512001600,jung2012a

A 10 kHz to 6 GHz Low-Cost Vector Network Analyzer - Depold, Andreas; Erhardt, Stefan; Weigel, Robert; Lurz, Fabian (Advances in Radio Science, 2021)

A 10 mW, 4 GHz CMOS Phase-Locked Loop with Dual-Mode Tuning Technique and Partly Integrated Loop Filter - Konstanznig, Georg; Weigel, Robert (IEEE Radio Frequency Integrated Circuits Symposium, 2003)
This publication presents the design of a 4 GHz Integer-N frequency synthesizer with dual-mode tuning technique. The 3rd order loop filter is partly integrated. The intended application is a direct conversion UMTS transmitter. The design has been realized using a 0.12 μm standard CMOS-process. The proposed advanced dual-mode tuning technique is based on digital coarse-tuning with subsequent analog fine-tuning. Therefore, the voltage controlled oscillator (VCO) features both, a digital and an analog tuning interface. This results in eight equidistant frequency bands. During coarse-tuning a digital control unit selects the correct frequency band for a certain frequency channel. The remaining frequency deviation is canceled through fine tuning, which is done by a conventional charge pump phase-locked loop (PLL). This results in lower spurious emission due to the smaller VCO gain. Lock-in times of 125 μs were achieved. The output frequency can be tuned from 3.8 GHz to 4.05 GHz with a channel spacing of 400 kHz. Except for the VCO with a supply voltage of 2.2 V and a current consumption of 1.9 mA to achieve higher output swing, the synthesizer is biased at 1.5 V consuming 4 mA. Thus, the overall power consumption can be stated with 10.2 mW.
elib2cris::1512001600,konstanznig2003a
Keywords: 3G mobile communication; Channel spacing; Charge pumps; Digital control; Filters; Frequency synthesizers; Phase locked loops; Transmitters; Tuning; Voltage-controlled oscillators

A 110-135 GHz Integrated Sixport Receiver Front-End in a 130-nm BiCMOS Technology - Völkel, Matthias; Borutta, Karl; Dietz, Marco; Aufinger, Klaus; Weigel, Robert; Hagelauer, Amelie Marietta (Asia-Pacific Microwave Conference, 2018)
In this paper, a fully monolithic low-power sixport receiver front-end working from 110 to 135GHz including an oscillator with divider stages, a passive sixport network and four detectors is presented. The measurement principle is based on an additive superposition of two incident millimeter-wave signals. The receiver circuit blocks are described and the measurement results are presented. All components have been designed using a 0.13μm 250GHz fT SiGe BiCMOS technology. The whole integrated circuit has a size of 1960μm x 1500μm including bondpads and consumes 100mA from a 3.3V and 82mA from a 1.8V supply. The receiver exhibits a 1 dB compression point of -1.3dBm at the center frequency of 121.5 GHz. The VCO has a tuning range of 27 GHz, with a best case phase noise of -110 dBc/Hz at 1MHz offset measured at the divider output for PLL stabilization. The maximum oscillator output power is -0.4 dBm.<br
Keywords: industrial radar; communication receiver; interferometer; phase measurement; sixport; low power; SiGe BiCMOS; millimeter-wave.

A 1.16 pJ/bit 80 Gb/s 2¹¹-1 PRBS generator in SiGe bipolar technology - Radwan, Ahmed; Talai, Armin; Weigel, Robert; Kissinger, Dietmar (9th European Microwave Integrated Circuit Conference (EuMIC), 2014)
A 211-1, 80Gb/s pseudo-random bit sequence (PRBS) generator, employing parallel architecture is presented. The generator is optimized to provide a high bit rate as well as a long sequence length without any need of inductive peaking for a lower power consumption, compared to PRBS generators reported in literature. The PRBS generator consists of two parallel complementary rows of linear feedback shift registers (LFSR), operating up to 40Gb/s, where the generated PRBS from each are multiplexed to provide a bit-rate of double the clock frequency, reaching up to 80Gb/s. The clock distribution network was carefully optimized for a reduced amplitude and phase error to push the boundaries of the maximum achievable bit-rate. The PRBS generator is capable of generating bit-rates ranging from 10Gb/s up to 80Gb/s, with a power consumption of 576 mW to 1 W. The circuit is manufactured in an 0.35 μm SiGe-Bipolar technology with an ft of 200 GHz.
elib2cris::1512001600,gharib2014b

A 120 GHz on-Chip Yagi-Uda Antenna with Backside Etching in 130 nm SiGe BiCMOS Technology - Lammert, Vincent; Weigel, Robert; Issakov, Vadim (2021 IEEE TEXAS SYMPOSIUM ON WIRELESS AND MICROWAVE CIRCUITS AND SYSTEMS (WMCS), 2021)
CRIS-Team WoS Importer:2021-10-15

A 122 GHz ISM-Band FMCW Radar Transceiver - Lammert, Vincent; Achatz, S.; Weigel, Robert; Issakov, V. (GeMIC 2020 - Proceedings of the 2020 German Microwave Conference, 2020)
In this work we present a 122 GHz FMCW radar module. It is based on an integrated transceiver in a 130nm SiGe technology. The chip is bonded to a PCB which contains the baseband circuits and the antennas. This paper discusses the design of the whole system around the transceiver IC, chip-to-PCB transition and the PCB antenna array. Finally, measurement results of a target at a distance of 6m are shown.
CRIS-Team Scopus Importer:2020-06-02
Keywords: D-band; ISM-Band; Radar; transceivers

A 122 GHz multiprobe reflectometer for dielectric sensor readout in SiGe BiCMOS technology - Lämmle, Benjamin; Schmalz, Klaus; Scheytt, Christoph; Kissinger, Dietmar; Weigel, Robert (IEEE Compound Semiconductor Integrated Circuits Symposium, 2011)
elib2cris::1512001600,laemmle2011a

A 122 GHz On-Chip 3-Element Patch Antenna Array with 10 GHz Bandwidth - Lammert, Vincent; Hamouda, Mohamed; Weigel, Robert; Issakov, Vadim (2020 50th European Microwave Conference, EuMC 2020, 2021)
This paper presents the design and measurements of a 122 GHz on-chip patch antenna array in a 130 nm SiGe BiCMOS technology. The array is formed by three rectangular patches in the top metallization layer with the ground plane in the lowest layer. Slots in the patches create a dual-resonance, which helps achieving a simulated bandwidth of 10 GHz and 28% radiation efficiency. The effects of fill structures between the patches and the ground plane are taken into consideration by introducing an equivalent dielectric constant. This makes the array fully compliant with metal density design rules of modern semiconductor processes, while maintaining good performance over a high bandwidth, which makes it attractive for numerous wideband applications, e.g. high-resolution short range radar or high data rate communications.
CRIS-Team Scopus Importer:2021-03-05
Keywords: D-Band; fill structures; metal density; On-chip antenna; patch array; SiGe BiCMOS; wideband

A 125-GHz permittivity sensor with read-out circuit in a 250-nm SiGe BiCMOS technology - Lämmle, Benjamin; Schmalz, Klaus; Scheytt, Christoph; Weigel, Robert; Kissinger, Dietmar (IEEE Transactions on Microwave Theory and Techniques, 2013)
elib2cris::1512001600,laemmle2013a

A 12 GHz all-digital PLL with linearized chirps for FMCW Radar - Kempf, Markus; Röber, Jürgen; Ohnhäuser, Frank; Weigel, Robert (2019 26th IEEE International Conference on Electronics, Circuits and Systems, ICECS 2019, 2019)
An accumulator based all-digital PLL for linear FMCW chirp generation is proposed. Operating at a Reference Frequency of 128 MHz the Phase Noise at 100 kHz offset measures -80 dBc/Hz. The proposed chirp linearization scheme allows for a wide range of chirp periods from 40 us up to 200 ms with an RMS Frequency Error of down to 7.26 kHz for slow and 882 kHz for fast chirps. Without dithering, the digitally, switched capacitor controlled oscillator presented in this work achieves an average step size of below 25 kHz while ranging from 11.596 GHz to 12.783 GHz.
CRIS-Team Scopus Importer:2020-02-21
Keywords: All-Digital Phase Locked Loops; Chirp Linearization; FMCW Radar; Frequency Synthesis

A 12-GHz High-Efficiency Tapered Traveling-Wave Power Amplifier With Novel Power Matched Cascode Gain Cells Using SiGe HBT Transistors - Sewiolo, Benjamin; Fischer, Georg; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2009)
In this paper, we present the analysis, design, and implementation of an integrated power distributed amplifier (DA), fabricated in a low-cost 0.25-mum SiGe BiCMOS technology. The circuit consists of four novel inductively peaked cascode gain cells, which are capacitively coupled to the base line for power optimization and bandwidth enhancement. Due to the tapered collector line, no output termination resistor is required, which provides higher efficiency. Design tradeoffs for maximum bandwidth, gain, output power, and efficiency are discussed by means of analytical calculations and simulations. A gain of 11 dB with a gain flatness of plusmn1 dB has been measured over a frequency range from 1 to 12 GHz. 19.5-dBm output power is obtained at the 1-dB compression point (P1 dB) in the desired frequency range with an associated power-added efficiency of 22.1% and a maximum output third-order intercept point of 31.5 dBm. The power dissipation of the amplifier is 400 mW from a 5-V supply. On-chip biasing is implemented via low dropout voltage reference driven by a bandgap voltage source. To the authors' knowledge, this is the highest output power achieved by an HBT DA in SiGe technology in this frequency range. The chip size is 2.1 mm2. Good agreement between simulation and measurement were achieved.
elib2cris::1512001600,sewiolo2009f

A 130 GHz Fully-Integrated Fundamental-Frequency D-Band Transmitter Module with > 4 dBm Single-Ended Output Power - Aguilar, Erick; Issakov, Vadim; Weigel, Robert (IEEE Transactions on Circuits and Systems II: Express Briefs, 2020)
A 130 GHz fully-integrated fundamental-frequency transmitter (TX) module with 4.4 dBm single-ended measured output power in a 130 nm SiGe technology is presented. The transmitter achieves in measurement a phase noise of-88 dBc/Hz at 1 MHz offset frequency from a 130 GHz carrier and a tuning range of 17 GHz. Its relatively compact size, low power consumption and high output power, enables the TX module to be integrated into more complex D-Band transceiver modules for radar and imaging applications. Due to the available measurement equipment, it was only possible to measure the output power single-ended. The measured single-ended output power is 4.4 dBm. This corresponds well to a simulated maximum differential output power of 8.1 dBm. To the best of the author's knowledge, the presented chip exhibits one of the highest output power for fundamental-frequency TX modules among the recently reported state-of-The art chips in this frequency range.
CRIS-Team Scopus Importer:2020-05-22
Keywords: BiCMOS integrated circuits; imaging; Millimeter-wave integrated circuits; radar; transmitters

A 130 GHz Fully-Integrated Fundamental-Frequency D-Band Transmitter Module with > 4 dBm Single-Ended Output Power - Aguilar Mendoza, Erick; Issakov, Vadim; Weigel, Robert (2020 International Symposium on Circuits and Systems (ISCAS), 2020)
A 130 GHz fully integrated fundamental frequency transmitter (TX) module with 4.4 dBm single-ended measured output power in a 130 nm SiGe technology is presented. The transmitter achieves in measurement a phase noise of -88 dBc/Hz at 1 MHz offset frequency from a 130 GHz carrier and a tuning range of 17 GHz. Its relatively compact size, low power consumption and high output power, enables the TX module to be integrated into more complex D-Band transceiver modules for radar and imaging applications. Due to the available measurement equipment, it was only possible to measure the output power single-ended. The measured single-ended output power is 4.4 dBm. This corresponds well to a simulated differential output power of 8.1 dBm.Based on simulation results, the TX module can produce a maximum output power of 8.1 dBm. To the best of the author’s knowledge, the presented chip exhibits the highest output power fundamental frequency TX module among the recently reported state-of-the art chips in this frequency range. <br

A 155 GHz Low-Power Total Power Radiometer in a 130 nm SiGe Technology - Aguilar Mendoza, Erick; Hagelauer, Amelie Marietta; Weigel, Robert (11th German Microwave Conference (GeMiC), 2018)
A low-power total power radiometer for passive imaging applications is presented. The radiometer is manufactured in a 130 nm SiGe technology with an f t /f max of 250/370 GHz. The radiometer achieves a minimum noise equivalent temperature difference (NETD) of 0.21 K at 155 GHz. By optimization of the building blocks and biasing stages, a low-power system with a total power consumption of 64 mW is achieved. Due to its low NEP and low-power consumption, the system enables further integration into high-density sensor arrays for passive radiometry in the D-Band.<br
Keywords: mm-wave; D-Band; Radiometer; Total Power Radiometer; Imaging

A 15-Gb/s PMCW Radar PRBS-Generator for MIMO and Joint Radar-Communication Systems - Probst, Florian; Engelmann, Andre; Hetterle, Philip; Issakov, Vadim; Weigel, Robert; Dietz, Marco (2022 Asia-Pacific Microwave Conference, 2022)
This paper presents an integrated baseband pseudo-random noise generator at 15 Gb/s for phase-modulated continuous-wave (PMCW) radar systems. Through slow-time modulating an outer code (OC) onto a pseudo-random binary sequence (PRBS), the circuit enables MIMO and joint radar-communication (RadCom) systems in the D-Band and above. To the best of the authors’ knowledge, this has not yet been demonstrated. The mixed-signal circuit consumes 7.2mW in power and 400 × 530μm2 in area. It was realized in a 22nm fully-depleted silicon on insulator (FDSOI) technology, where the PRBS is generated by a shift register formed by true single-phaseclock (TSPC) flip-flops.<br
Keywords: MIMO radar; phase-modulated continuouswave (PMCW); radar-communication (RadCom); true singlephase-clock (TSPC).

A 15GHz Bandwidth High Efficiency Power Distributed Amplifier for Ultra-Wideband-Applications Using a Low-Cost SiGe BiCMOS Technology - Sewiolo, Benjamin; Fischer, Georg; Weigel, Robert (IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2009, 2009)
In this paper the analysis, design and characterization of a 15 GHz power distributed amplifier for ultra-wideband radar and sensing applications are presented. The amplifier is fabricated in a low-cost 0.25 mum SiGe BiCMOS technology with a transit frequency ft of 25 GHz. The circuit integrates four common-emitter gain cells, which are capacitively coupled to the base line for power optimization. Collector line tapering has been used for efficiency improvement. 13.5 dBm output power has been measured at the 1 dB compression point (P1dB) in the desired frequency range with an associated gain of 9.5 dB and a gain flatness of plusmn0.5 dB with total power consumption of 140 mW. The peak power added efficiency (PAE) at P1dB is 13.8%. The chip size of the compact amplifier is 1.45 mm2. Good agreement between simulation and measurement was achieved.
elib2cris::1512001600,sewiolo2009b

A 16-Channel Synchronous Sampling Power Measurement System For Wireless Health Assistance Devices - Reuter, Lukas Michael; Weigel, Robert; Fischer, Georg (IEEE International Symposium on Medical Measurements and Apllications Proceedings (MeMeA), 2012)
A multi-channel synchronous sampling hardware for power measurement applications is described. Future body-worn medical devices for ambient assisted living should allow for battery run-times of several days without any user interaction for charging. In order to achieve this very challenging goal, a first step is the characterization of the components within medical devices by their power consumption or charging power in order to create models of power consumption over time. Medical devices often include several sensors and wireless interfaces which are known to be the most power consuming. This paper describes a hardware that is used as a tool for the measurement of power consumption of specific peripherals on a medical ambient assisted living device during development. Thus a model can be derived that can help optimizing battery run-time by deciding when to use which interface for data transmission or sensor data acquisition. Furthermore, the tool can quantify the amount of energy gained from an energy harvester. By assessing power drained from battery and power harvested the battery status over time can be studied and charging intervals derived.
elib2cris::1512001600,reuter2012a
Keywords: Ambient Assisted Living (AAL); medical devices; power measurement; wireless health assistance; energy harvesting; energy consumption characterization

A 180 GHz Frequency Multiplier in a 130 nm SiGe BiCMOS Technology - Girg, Thomas; Beck, Christopher; Dietz, Marco; Hagelauer, Amelie Marietta; Kissinger, Dietmar; Weigel, Robert (2016 IEEE 14th International NEWCAS Conference, 2016)
An integrated analog frequency multiplier for a novel high data rate communication system has been developed to multiply a 18 GHz input signal by ten to generate a 180 GHz output signal. With a first step the 18 GHz input signal is fed into a times five edge combiner, which generates an intermediate frequency of 90 GHz. Therefore five different phases with a delta of 72 degree are needed, that are provided by an active allpass filter chain. In a second step the 90 GHz intermediate frequency is given into a double-balanced Gilbert cell mixer. Here, frequency doubling is achieved by feeding the same signal into the LO and RF port of the mixer. Hence, the overall output frequency of 180 GHz results in 180 GHz with a simulated output power of -7 dBm. All simulations are done post-layout. The chip is implemented in a 130 nm BiCMOS technology with a chip area of 0.9 mm x 1 mm.
elib2cris::1512001600,girg2016
Keywords: SiGe BiCMOS; high data rate communication; 180 GHz; simultaneous phase and amplitude regenerative sampling; transmitter; frequency multiplier

A 1.8-mW Low Power, PVT-Resilient, High Linearity, modified Gilbert-Cell Down-Conversion Mixer in 28-nm CMOS - Ciocoveanu, Radu; Rimmelspacher, Johannes; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2018)
This paper presents a high linearity modified Gilbert-cell mixer designed for 60-GHz applications and fabricated in a 28-nm CMOS technology. To increase the linearity of the mixer, the RF transconductance stage was removed, thereby reducing the amount of stacked transistors. We propose using a self-biasing Vth reference in the bias network to make the mixer more robust to process-voltagetemperature (PVT) variations. Measurement results show that this mixer achieves a voltage conversion gain of 4.7 dB, a 1-dB compression point of -3 dBm and a 12.3 dB noise figure, while it draws only 2 mA from a single 0.9 V supply. The occupied area on the chip is 0.35x0.68 mm2 including pads.
Keywords: Down-Conversion Mixer; High-Linearity; Low-Power; PVT Robust

A 1 to 32 GHz broadband multi-octave receiver for monolithic integrated vector network analyzers in SiGe technology - Dietz, Marco; Bauch, Andreas; Aufinger, Klaus; Weigel, Robert; Hagelauer, Amelie Marietta (International Journal of Microwave and Wireless Technologies, 2018)
A multi-octave receiver chain is presented for the use in a monolithic integrated vector network analyzer. The receiver exhibits a very wide frequency range of 1–32 GHz, where the gain meets the 3 dB-criterion. The differential receiver consists of an ultra-wideband low noise amplifier, an active mixer and an output buffer and exhibits a maximum conversion gain (CG) of 16.6 dB. The main design goal is a very flat CG over five octaves, which eases calibration of the monolithic integrated vector network analyzer. To realize variable gain functionality, without losing much input matching, an extended gain control circuit with additional feedback branch is shown. For the maximum gain level, a matching better than −10 dB is achieved between 1–28 GHz, and up to 30.5 GHz the matching is better than −8.4 dB. For both, the input matching and the gain of the LNA, the influence of the fabrication tolerances are investigated. A second gain control is implemented to improve isolation. The measured isolations between RF-to-LO and LO-to-RF are better than 30 dB and 60 dB, respectively. The LO-to-IF isolation is better than 35 dB. The noise figure of the broadband receiver is between 4.6 and 5.8 dB for 4–32 GHz and the output referred 1-dB-compression-point varies from 0.1 to 4.3 dBm from 2–32 GHz. The receiver draws a current of max. 66 mA at 3.3 V.<br
Keywords: active circuits; RF front-ends; ultra broadband receiver

A 200 - 325 GHz Gain-Boosted J-Band Low-Noise Amplifier in a 130 nm SiGe BiCMOS Technology - Koch, Manuel; Breun, Sascha; Weigel, Robert (Radio Wireless Week, 2024)
This paper presents a wideband low-noise amplifier covering the complete J-Band up to the band edge of 325 GHz. A peak gain of 17.4 dB is achieved by a four-stage cascode-based prototype using inductive and capacitive gain boosting techniques. It is manufactured in a 130 nm SiGe BiCMOS technology with ft/fmax of 350 GHz/450 GHz, respectively. Zero-Ohm lines are applied to bias the amplifier and low-loss Marchand baluns facilitate single-ended measurements. At both edges of the measured frequency range, a gain of at least 17 dB is shown, while a minimum gain of 12.1 dB is reported. Simulations predict a noise figure of 13.1 dB to 17.2 dB and an input-referred compression point better than −23 dBm, making the amplifier suitable for sub-terahertz radar and wireless communication within IEEE 802.15.3d frequency bands. A core chip area of 250×230μ m2 and a DC power of 162 mW are require
Keywords: BiCMOS integrated circuits; Millimeter wave integrated circuits; Broadband amplifiers; Low-noise amplifiers; Baluns

A 20.7% PAE 3-Stage 60 GHz Power Amplifier for Radar Applications in 28 nm Bulk CMOS - Ciocoveanu, Radu; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (2019 14th European Microwave Integrated Circuits Conference (EuMIC), 2019)
This paper presents a highly efficient 3-stage differential Class-B power amplifier (PA) for short range radar applications, realized in a 28nm bulk CMOS technology. Measurement results show a saturated output power (Psat) of 11.9dBm with a 20.7% power-added efficiency (PAE) at 60 GHz. Moreover, the measurements show that for a frequency range from 57 GHz to 64 GHz, the Psat varies from 10.5dBm to 11.2dBm and the circuit draws 26mA from a 0.9V power supply. Furthermore, the fabricated chip has an area of 0.61mm x 0.31mm including the pads.<br
Keywords: Differential PA; 60 GHz; 28nm CMOS; High Efficiency.

A 20-Gbps Low Jitter Analog Clock Recovery Circuit for Ultra Wide Band Radio Systems - Hamouda, Mohammed; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (IEEE International Symposium on Circuits and Systems, 2014)
elib2cris::1512001600,hamouda2014a
Keywords: PLL; UWB; Radio; radar

A 2–12 GHz power distributed amplifier for broadband localization- and sensor systems based on PN-sequences - Sewiolo, Benjamin; Weigel, Robert (IEEE International Conference on Ultra-Wideband, 2008, 2008)
In this paper the analysis, design and measurement of a 2-12 GHz power distributed amplifier for ultra-wideband localization- and sensor applications is presented. The circuit integrates four cascode gain cells, which are capacitively coupled to the base line for power optimization. The collector line has been tapered for efficiency improvement. More than 14 dBm have been measured in the desired frequency range with an associated gain of 9 dB and a gain flatness of plusmn0.5 dB with total power consumption of 250 mW. To the authors knowledge, this is the highest output power achieved by a distributed amplifier in SiGe technology in this frequency range. The chip size of the compact amplifier is 1.16 mm2 and has been fabricated in a low-cost 0.25 mum SiGe BiCMOS technology with a transit frequency of 25 GHz. Good agreement between simulation and measurement were achieved.
elib2cris::1512001600,sewiolo2008b

A 21 Gb/s Arbitrary Binary Sequence Generator for PMCW Radar based on a TSPC Serializer in 22 nm FDSOI - Probst, Florian; Engelmann, Andre; Issakov, Vadim; Weigel, Robert (IEEE MTT-S International Microwave Symposium Digest, 2023)
This work presents an arbitrarily programmable pseudo-random binary sequence (PRBS) generator for phase-modulated continuous-wave (PMCW) radar transmitters. It incorporates a mixed-signal architecture with a digitally implemented shift register connected to a novel serializer architecture based on true single-phase-clock (TSPC) flip-flops. Unlike static, non-configurable linear-feedback shift registers (LFSRs), this circuit can generate more complex sequences, like the almost perfect auto-correlation sequence (APAS), that exhibit a better radar performance. The circuit is realized on a 22nm fully-depleted silicon on insulator (FDSOI) technology and consumes a total chip area of 600×530µm2. On-wafer measurements show a maximum chip rate of 21Gb/s at a 16.9mW power consumption. To the best of the authors' knowledge, the proposed circuit marks the first programmable PRBS generator operating at this high chip rate. It paves the way for on-chip generation of complex broadband sequences for millimeter-wave digital MIMO radar systems for consumer or automotive applications.
CRIS-Team Scopus Importer:2023-09-01
Keywords: Almost perfect auto-correlation sequences (APAS); fully-depleted silicon on insulator (FDSOI); phase-modulated continuous-wave (PMCW) radar; pseudo-random binary sequence (PRBS) generator; true single-phase-clock (TSPC) flip-flop

A 220-325 GHz Subharmonic Receiver with 14.8 dB Peak Conversion Gain for FMCW Radar in SiGe BiCMOS Technology - Schrotz, Albert-Marcel; Breun, Sascha; Issakov, Vadim; Dietz, Marco; Weigel, Robert (IEEE Radio & Wireless Week, 2022)

A 2-30 GHz Multi-Octave Planar Microwave Six-Port for Reﬂectometry Applications - Bauch, Andreas; Hofmann, Maximilian; Nehring, Johannes; Weigel, Robert; Kissinger, Dietmar (European Microwave Conference (EuMC), 2015)
This paper presents a planar multilayer six-port circuit implementation based on multi-octave directional couplers. The presented six-port circuit is the first published six-port, that is capable of operating in an ultra-boradband frequency range from 2 to 30 GHz. Within this spectrum the six-port allows for the determination of the complex reflexion coefficient through four scalar power measurements. The six-port circuit is based on the quasi-optimal design proposed by Engen. Proper functionality has been verified through measurements of the S-parameters and the calculated q-points.
elib2cris::1512001600,bauch2015

A 24 GHz Dual-Polarized and Robust Dielectric Rod Antenna - Sporer, Michael; Weigel, Robert; Kölpin, Alexander (IEEE Transactions on Antennas and Propagation, 2017)

A 24 GHz Waveguide based Radar System using an Advanced Algorithm for I/Q Offset Cancelation - Will, Christoph; Linz, Sarah; Mann, Sebastian; Lurz, Fabian; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (Kleinheubacher Tagung, 2016)
elib2cris::1512001600,will2016a

A 24 GHz Waveguide based Radar System using an Advanced Algorithm for I/Q Offset Cancelation - Will, Christoph; Linz, Sarah; Mann, Sebastian; Lurz, Fabian; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (Advances in Radio Science, 2017)
Precise position measurement with micrometer accuracy plays an important role in modern industrial applications. Herewith, a guided wave Six-Port interferometric radar system is presented. Due to limited matching and discontinuities in the radio frequency (RF) part of the system, the designers have to deal with DC offsets. The offset voltages in the baseband lead to worse relative modulation dynamics relating to the full scale range of the analog-to-digital converters and thus, considerably degrade the system performance. While common cancelation techniques try to estimate and extinguish the DC offsets directly, the proposed radar system is satisfied with equalizing both DC offsets for each of the two differential baseband signal pairs. Since the complex representation of the baseband signals is utilized for a subsequent arctangent demodulation, the proposed offset equalization implicates a centering of the in-phase and quadrature (I/Q) components of the received signal, which is sufficient to simplify the demodulation and improve the phase accuracy. Therefore, a standard Six-Port radar system is extended and a variable phase shifter plus variable attenuators are inserted at different positions. An intelligent algorithm adjusts these configurable components to achieve optimal I/Q offset cancelatio

A 24 GHz Wireless Sensor Network with High Precision Local Positioning Capability - Ferizi, Alban; Jung, Melanie; Weigel, Robert (IMS 2011 Workshop: Smart Wireless Sensor Networks (MTT-S), 2011)
elib2cris::1512001600,ferizi2011

A 2.4-µA 868-MHz low latency wake-up receiver for strong interference channels - Milosiu, Heinrich; Oehler, Frank; Weigel, Robert (European Microwave Integrated Circuits Conference, 2013)
This paper describes an innovative approach for integrated ultra-low current wireless receivers for UHF bands in a 180-nm CMOS technology. The classical method of slow periodic switching off of the receiver was picked up, essentially enhanced and applied to a superheterodyne receiver topology. A novel fast sampling pulse operation method for ultra low power integrated receivers is presented meeting both short reaction time and very low power consumption requirements. In addition, the receiver was designed for radio channels with strong interferers. The presented ASIC comprises both an analogue front-end and two digital 31 bit correlating decoders. The current consumption of the fabricated prototype is 2.4 μA at 3 volts supply voltage with a reaction time of 485 ms.
elib2cris::1512001600,milosiu2013

A 2.5 GHz Low Noise Phase Locked Surface Transverse Wave VCO - Fleischmann, Bernd; Roth, Alexander; Russer, Peter; Weigel, Robert (Proc. IEEE Ultrasonics Symposium, 1989, 1989)
A hybrid VCO (voltage-controlled oscillator) at 2.488 GHz which is phase locked to a crystal oscillator operating at 75.4 MHz is described. Acoustic surface transverse wave (STW) delay lines operating at the fifth harmonic are used as the frequency-controlling element of the VCO. In order to reduce the delay-line electromagnetic feedthrough a three-transducer-type STW filter design is combined with a microstrip rat-race coupler. The filters were designed using advanced analysis methods and fabricated on rotated Y-cut quartz substrates with a standard photolithographic process. The delay lines were characterized by a center frequency of 2.49 GHz, an untuned insertion loss of 22 dB, an unloaded Q value of 1280, and a group delay time of 158 ns. The signal of the VCO is mixed with the local (crystal) oscillator signal multiplied by 32, thus providing an IF (intermediate frequency) signal of 75.4 MHz that feeds the phase-locked loop, which has a bandwidth of 300 kHz. A single-sideband phase-noise-to-carrier ratio of -112 dBc/Hz at 1-kHz offset has been attained
–empty–::1512001600,fleischmann1989a
Keywords: acoustic delay lines; phase-locked loops; surface acoustic wave devices; ultrasonic devices; variable-frequency oscillators; 158 ns; Q value; acoustic surface transverse wave delay lines

A 268-325 GHz 5.2 dBm Psat Frequency Doubler using Transformer-Based Mode Separation in SiGe BiCMOS Technology - Breun, Sascha; Schrotz, Albert-Marcel; Dietz, Marco; Issakov, Vadim; Weigel, Robert (2021 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), 2022)

A 28 GHz Broadband Low Noise Amplifier in a 130 nm BiCMOS Technology for 5G Applications - Kolb, Katharina; Potschka, Julian; Maiwald, Tim; Aufinger, Klaus; Dietz, Marco; Weigel, Robert (IEEE Microwave and Radar Week, 2020)
This paper presents a 28GHz broadband low noise amplifier (LNA) with a fractional bandwidth > 32 % for 5G wireless communication systems. The LNA provides a very low noise figure, a high linearity and a compact size. These properties are essential in a 5G MIMO receiver front-end. The LNA is designed in a 130 nm SiGe BiCMOS technology and provides 24 dB gain at 28 GHz with a 3 dB-bandwidth from 21.4 t 30.6 GHz. The simulated noise figure at 28GHz yields 2.18 dB. An input-referred 1 dB-compression point of -13.0 dBm is reached with a DC-power consumption of 25.1 mW <br
Keywords: 5G mobile communication; BiCMOS integrated circuits; low noise amplifier (LNA); millimeter-wave integrated circuits; noise figure; optimal matching

A 28 GHz Highly Accurate Phase- and Gain- Steering Transmitter Frontend for 5G Phased-Array Applications - Kolb, Katharina; Potschka, Julian; Maiwald, Tim; Aufinger, Klaus; Hagelauer, Amelie; Dietz, Marco; Weigel, Robert (IEEE International Midwest Symposium on Circuits and Systems, 2020)
This paper presents a 28 GHz highly accurate phase- and gain-steering transmitter frontend for 5G phased-array repeater applications. It is designed in a 130 nm SiGe BiCMOS technology. The transmitter chain consists of a highly accurate 7-bit phase shifter, a 5-bit variable gain amplifier and an exceedingly linear analog predistorted power amplifier. The frontend provides up to 31.9 dB gain at 28 GHz and offers steering ranges of 9 dB for gain and 360 ° for phase. The root mean square (RMS) phase error of the transmitter frontend is less than 3.1 °, the RMS gain error results to 0.5 dB. An output-referred 1-dB-compression point of 9.9 dBm is achieved with a DC power consumption of 127.9 mW at voltage levels of 3.3/4.0 V. <br
Keywords: 5G mobile communication; beam-steering; millimeter-wave integrated circuits; phased-arrays

A 28 nm standard CMOS watt-level power amplifier for LTE applications - Fuhrmann, Jörg; Obmann, Patrick; Dufrene, Krzysztof; Pretl, Harald; Weigel, Robert (IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications (PAWR), 2015)
In this paper, a 28nm radio frequency (RF) complementary metal-oxide-semiconductor (CMOS) power amplifier (PA) is presented. It was designed to meet 3GPP TS 36.101 V10.10.0 requirements for Long Term Evolution (LTE). The design was tested on board and has full onchip matching. Furthermore, the biasing for class-AB is also implemented on chip. The maximum gain is more than 15 dB until 0dBm input power. It achieves a power added efficiency (PAE) of 35.2 %, a drain efficiency (DE) of 39.5% and a maximum output power Pmax of 31.7dBm at a frequency of 1.83 GHz. The adjacent channel leakage power ratio (ACLR) for the evolved universal terrestrial radio access (E-UTRA) measured for full allocated LTE15 PUSCH are for the lower band 33.2 dBc and for the upper band 33.2 dBc. The UTRAACLR for the lower and upper band is 36.2 dBc and 35.1 dBc, respectively. The Error Vector Magnitude (EVM) is 4.8% for a quadrature phase-shift keying (QPSK) and 3.8% for a 16 quadrature amplitude modulation (16QAM) signal.
elib2cris::1512001600,fuhrmann2015

A 2^9 - 1 up to 25 Gb/s M-Sequence Generator IC for UWB Radar Applications in a Low-Cost SiGe BiCMOS Technology - Lämmle, Benjamin; Wagner, Christoph; Knapp, Herbert; Maurer, Linus; Weigel, Robert (German Microwave Conference, 2009)
elib2cris::1512001600,laemmle2009

A 295-337 GHz 2.5 dBm Psat Cascode-Based Frequency Doubler in SiGe BiCMOS Technology - Breun, Sascha; Schrotz, Albert-Marcel; Dietz, Marco; Issakov, Vadim; Weigel, Robert (2022 IEEE 22nd Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF), 2022)

A 29 GHz frequency divider in a miniaturized leadless flip-chip plastic package - Engl, Mario; Pressel, Klaus; Dangelmaier, Jochen; Theuss, Horst; Eisener, B.; Eurskens, Wolfram; Knapp, Herbert; Simbürger, Werner; Weigel, Robert (IEEE MTT-S International Microwave Symposium Digest, 2004)
We present a static frequency divider operating up to 29 GHz in a tiny leadless plastic package. This innovative package, which is intended for high volume production at low cost, has an ultra-miniaturized footprint with a standard pad pitch of 0.5 mm and a standard package height of 0.4 mm. To demonstrate the high frequency capabilities of the package we show the performance up to 29 GHz of a frequency divider with a divide ratio of 16. The circuit is manufactured in a standard SiGe BiCMOS technology for volume production (Infineon B7HFC).
elib2cris::1512001600,engl2004

A 2 GHz Surface Transverse Wave Oscillator with Low Phase Noise - Fleischmann, Bernd; Eichinger, Ludwig; Russer, Peter; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 1988)
A hybrid oscillator at 1.9805 GHz using acoustic surface transverse wave (STW) delay lines operating at the third harmonic as the frequency controlling element is discussed. The STW delay lines were fabricated on 37.5 degrees -rotated Y-cut quartz substrates with a photolithographic technique. A very thin metallization (25 nm) was used to obtain low insertion loss. A split isolated electrode design was used for the transducers. The Q-value and the untuned insertion loss of the STW filter were 3400 and 21 dB, respectively. The phase noise and temperature stability of the oscillator were characterized. At a power output of 6.5 dBm a single-sideband phase noise-to-carrier ratio of -100 dBc/Hz at 1 kHz was attained.<>
null::1512001600,fleischmann1988
Keywords: acoustic microwave devices; hybrid integrated circuits; microwave integrated circuits; microwave oscillators; radiofrequency oscillators; SAW device; acoustic surface transverse wave; transducers

A 2-Step Subspace Projection Approach for Generating Compact, Provably Passive, Reduced-Order Macromodels for Interconnect Circuits - Steinmair, Gernot; Troescher, Matthias; Stelzer, Andreas; Weigel, Robert (Proceedings of the Asia-Pacific Microwave Conference, 2002)
elib2cris::1512001600,steinmair2002

A 2-watt, 0.15-µm GaAs pHEMT stacked amplifier at 22 GHz - Fersch, Thomas; Weigel, Robert; Quaglia, Roberto; Pirola, Marco; Ghione, Giovanni; Camarchia, Vittorio (MIKON, 2014)
elib2cris::1512001600,fersch2014

A 30GHz bandwidth driver amplifier with high output voltage swing for ultra-wideband localization- and sensor systems - Sewiolo, Benjamin; Rascher, Jochen; Weigel, Robert (Asia-Pacific Microwave Conference, 2008, 2008)
This paper reports on the analysis, design and characterization of a 30 GHz lumped broadband driving amplifier for ultra-wideband localization and sensor systems. The circuit integrates a cascode differential stage, which is fed by two cascaded emitter-followers (EF). The differential gain is 10 dB with a gain flatness of plusmn1 dB in the desired frequency range. This amplifier exhibits an output 1-dB compression point of 12 dBm. The maximum differential output voltage swing is 3.2 Vpp. The amplifier consumes a power of 560 mW at a supply voltage of plusmn3.3 V. The compact 0.5 mm2 amplifier is manufactured in a low-cost 0.25 mum SiGe BiCMOS technology with a transit frequency of 75 GHz.
elib2cris::1512001600,sewiolo2008c

A 30 GHz Variable Gain Amplifier With High Output Voltage Swing for Ultra-Wideband Radar - Sewiolo, Benjamin; Fischer, Georg; Weigel, Robert (IEEE Microwave and Wireless Components Letters, 2009)
This paper reports on the analysis, design and characterization of a 30 GHz fully differential variable gain amplifier for ultra-wideband radar systems. The circuit consists of a variable gain differential stage, which is fed by two cascaded emitter followers. Capacitive degeneration and inductive peaking are used to enhance bandwidth. The maximum differential gain is 11.5 dB with plusmn1.5 dB gain flatness in the desired frequency range. The amplifier gain can be regulated from 0 dB up to 11.5 dB. The circuit exhibits an output 1 dB compression point of 12 dBm. The measured differential output voltage swing is 1.23 Vpp. The 0.75 mm2 broadband amplifier consumes 560 mW at a supply voltage of plusmn3.3 V. It is manufactured in a low-cost 0.25 mum SiGe BiCMOS technology with a cut-off frequency of 75 GHz. The experimental results agree very well with the simulated response. A figure of merit has been proposed for comparing the amplifier performance to previously reported works.
elib2cris::1512001600,sewiolo2009d

A 314-344 GHz Frequency Doubler with Driving Stage and 1 dBm Psat in SiGe BiCMOS Technology - Breun, Sascha; Schrotz, Albert-Marcel; Dietz, Marco; Issakov, Vadim; Weigel, Robert (IEEE Radio & Wireless Week, 2021)

A 31-dBm, high ruggedness power amplifier in 65-nm standard CMOS with high-efficiency stacked-cascode stages - Leuschner, Stephan; Pinarello, Sandro; Hodel, Uwe; Müller, Jan-Erik; Klar, Heinrich (Radio Frequency Integrated Circuits Symposium (RFIC), 2010 IEEE, 2010)

A 33% Tuning Range High Output Power V-Band Superharmonic Coupled Quadrature VCO in SiGe Technology - Nasr, Ismail; Dudek, Manuel; Weigel, Robert; Kissinger, Dietmar (IEEE Radio Frequency Integrated Circuits Conference, 2012)
Abstract—This paper presents a wide tuning range superharmonic coupled quadrature Colpitts VCO with high output power. The circuit was fabricated using a low-cost SiGe technology with an ft/fmax of 200/250 GHz. The quadrature VCO employs a novel area efficient coupling technique that uses second harmonic coupling. Downcoversion mixers are implemented to provide an intermediate frequency signal, enabling easier measurement. A phase imbalance below 2 degrees is measured between the quadrature outputs, over a 6 GHz tuning range. The quadrature VCO can be tuned between 55 and 76.5 GHz having a record tuning range of approx. 33%. Moreover, the quadrature VCO has a maximum measured output power of +10.5dBm, and a minimum phase noise of -97 dBc/Hz. The overall chip draws 303mA from a 3.3V supply.
elib2cris::1512001600,nasr2012a
Keywords: Quadrature oscillator (QVCO); Colpitts; Wide tuning range; superharmonic coupling

A 34 GHz CMOS VCO with Transformer Tail-Node Filter and TSPC Frequency Divider in 22 nm FDSOI - Engelmann, Andre; Probst, Florian; Hetterle, Philip; Weigel, Robert (2024 IEEE Radio and Wireless Week, RWW 2024 - 2024 IEEE 24th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, SiRF 2024, 2024)
This work proposes a compact, low-power CMOS voltage-controlled oscillator (VCO) with distributed transformer tail-node filter for phase noise reduction. The circuit is integrated into a 22 nm fully-depleted silicon-on-insulator (FDSOI) technology, offering high-performance n- and p-MOS transistors. Using a combination of SOI varactors and switched capacitors, a wide tuning range of 22.8%, covering 30.4 to 38.24 GHz, is reached while maintaining a phase noise below -97 dBc/Hz at a 1 MHz carrier offset. An area- and power-efficient true single-phase-clock (TSPC) frequency divider is implemented to ease the use of the VCO within a low-frequency PLL. The overall circuit consumes 9.4 mW supplied from a 0.8 V source and 170 370 m2 core area, including an output buffer and the divider. The circuit performance results in a corresponding FOM and FOMT of -178.3 and -185.3 dBc/Hz.
CRIS-Team Scopus Importer:2024-03-15
Keywords: CMOS; Cross-coupled VCO; FDSOI; frequency divider; low phase-noise; oscillator; signal generation; tail filter

A 34 GHz CMOS VCO with Transformer Tail-Node Filter and TSPC Frequency Divider in 22 nm FDSOI - Engelmann, Andre; Probst, Florian; Hetterle, Philip; Weigel, Robert (2024)
This work proposes a compact, low-power CMOS voltage-controlled oscillator (VCO) with distributed transformer tail-node filter for phase noise reduction. The circuit is integrated into a 22nm fully-depleted silicon-on-insulator (FDSOI) technology, offering high-performance n- and p-MOS transistors. Using a combination of SOI varactors and switched capacitors, a wide tuning range of 22.8%, covering 30.4 to 38.24 GHz, is reached while maintaining a phase noise below -97 dBc/Hz at a 1MHz carrier offset. An area- and power-efficient true single-phase-clock (TSPC) frequency divider is implemented to ease the use of the VCO within a low-frequency PLL. The overall circuit consumes 9.4mW supplied from a 0.8V source and 170 370μm² core area, including an output buffer and the divider. The circuit performance results in a corresponding FOM and FOMT of -178.3 and -185.3 dBc/Hz.
https://cris.fau.de/converis/publicweb/Publication/311361745

A 366 mW Direct Digital Synthesizer at 15 GHz Clock Frequency in SiGe Bipolar Technology - Lämmle, Benjamin; Wagner, Christoph; Knapp, Herbert; Maurer, Linus; Weigel, Robert (Radio Frequency Integrated Circuits Symposium, 2009)
elib2cris::1512001600,laemmle2009a

A 3-Stacked 10.2 dBm OP1dB D-Band Power Amplifier in 22 nm FDSOI for 6G Communication - Huang, Tianzhu; Engelmann, Andre; Hetterle, Philip; Probst, Florian; Weigel, Robert (2023 Asia-Pacific Microwave Conference, 2023)
This paper proposes a high-linearity 3-stacked D-band power amplifier (PA) for 6G communication. The PA is fabricated in 22 nm fully-depleted silicon-on-insulator (FDSOI) CMOS technology and consists of four stages, including three driver stages. The capacitive neutralization approach is adopted in all stages for gain-boosting. Transistor stacking is applied in the output stage for high output power and linearity. The circuit achieves a peak power gain of 23.8 dB at 135 GHz with a 3-dB bandwidth of 16 GHz. A maximum measured output power of 13 dBm, an output referred 1-dB compression point OP1dB of 10.2 dBm, and a peak power-added efficiency (PAE) of 9.9% are attained, while occupying only 0.081 mm² of chip are
Keywords: CMOS; D-band; FDSOI; high linearity; mm-wave; power amplifier (PA); stacked amplifier; 6G

A 4–32-GHz Chipset for a Highly Integrated Heterodyne Two-Port Vector Network Analyzer - Nehring, Johannes; Dietz, Marco; Aufinger, Klaus; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE Transactions on Microwave Theory and Techniques, 2016)

A 50-100-GHz Highly Integrated Octave-Bandwidth Transmitter and Receiver Chipset in 0.35um SiGe Technology - Nasr, Ismail; Knapp, Herbert; Aufinger, Klaus; Weigel, Robert; Kissinger, Dietmar (IEEE Transactions on Microwave Theory and Techniques, 2014)
This work presents a highly integrated transmitter (TX) and receiver (RX) chipset operating from 50 to 100 GHz. The local oscillator (LO) is realized using a high output power millimeter-wave integrated frequency synthesizer with an octave output frequency range. The proposed low-complexity discrete tuned synthesizer architecture employs a single wide-tuning range voltage-controlled oscillator core and a single-sideband mixer, which can be switched to operate as a LO amplifier. An ultra broadband variable gain amplifier, with a gain control range >hbox 25 dB, is used at the output of the synthesizer to provide a tunable output power. A maximum output power from +hbox7 to +hbox12 dBm and an output phase noise from -hbox83 to -hbox96 dBc/Hz at 1-MHz offset are measured over the complete output frequency range. Moreover, a spurious suppression >hbox 22 dB is achieved over the entire synthesizer's tuning range. The RX shows a conversion gain >hbox 19 dB and a noise figure < hbox 9.5 dB from 50 to 100 GHz. The TX's measured saturated output power is from +hbox6 to -hbox1 dBm over the entire frequency range. The complete chipset is realized in a commercial low-cost SiGe:C technology with an f- t/f_max of hbox170/250 GHz. Each of the TX and RX chips including the frequency synthesizers draw a current of 370 mA from a 3.3-V supply.
elib2cris::1512001600,nasr2014

A 50 to 100GHz frequency synthesizer with 17dB side-band suppression using a single VCO core - Nasr, Ismail; Weigel, Robert; Kissinger, Dietmar (The European Microwave Integrated Circuits Conference (EuMIC), 2013)
elib2cris::1512001600,nasr2013a

A 5.25 GHz SiGe bipolar power amplifier for IEEE 802.11a wireless LAN - Bakalski, Winfried; Kitlinski, Krzysztof; Donig, Günther; Kapfelsperger, Boris; Österreicher, Wilfried; Auchter, Wolfgang; Weigel, Robert; Scholtz, Arpad (Radio Frequency Integrated Circuits (RFIC) Symposium, 2004)
An integrated wireless LAN radio frequency power amplifier (PA) for 5.25 GHz has been realized in a 40 GHz-fT, 0.35 μm-SiGe-bipolar technology. The single-ended 3-stage power amplifier uses on-chip inductors and a short on-chip stripline for the interstage matching. At 3.3 V supply voltage the OP1dB is 23.8 dBm, and a saturated output power of 25.9 dBm is achieved at 5.25 GHz. The PAE at the OP1dB is 24%. The small-signal gain is 27 dB.
elib2cris::1512001600,bakalski2004

A 52-to-61 GHz Push-Push VCO in 28 nm CMOS - Issakov, Vadim; Padovan, Fabio; Rimmelspacher, Johannes; Weigel, Robert; Geiselbrechtinger, Angelika (European Microwave Conference 2018, 2018)
We present a continuously tunable 52-to-61 GHz push-push cross-coupled voltage-controlled oscillator (VCO) in a 28 nm bulk CMOS technology. The second harmonic is extracted in a non-invasive way using a transformer. The primary side acts simultaneously as a second harmonic filter and a balun. The VCO achieves in measurement a low phase noise of -87 dBc=Hz at 1 MHz offset at 60 GHz and an output power of -23 dBm. The VCO including buffers dissipates 49 mA from a single 0:9 V supply, while the VCO core consumes only 12 mA. It occupies a chip area of only 0:28 mm2 including pads. The VCO achieves a continuously tunable frequency tuning range (FTR) of 16%. The circuit is suitable for 60 GHz FMCW radar applications.<br

A 52-to-67 GHz dual-core push-push VCO in 40-nm CMOS - Issakov, Vadim; Rimmelspacher, Johannes; Rimmelspacher, Johannes; Trotta, Saverio; Tiebout, Marc; Hagelauer, Amelie Marietta; Weigel, Robert (International Journal of Microwave and Wireless Technologies, 2018)
We present a continuously tunable 52-to-67 GHz push-push dual-core voltage-controlled oscillator (VCO) in a 40 nm bulk complementary metal-oxide-semiconductor (CMOS) technology. The circuit is suitable for 60 GHz frequency-modulated-continuous-wave radar applications requiring a continuously tunable ultra-wide modulation bandwidth. The LC-tank inductor is used to couple the two VCO cores. The fundamental frequency of the VCO can be tuned from 26 to 33.5 GHz, which corresponds to a frequency tuning range of 25%. The second harmonic is extracted in a non-invasive way using a transformer. The primary side acts simultaneously as a second harmonic filter. The VCO achieves in measurement a low phase noise of -91.8 dBc/Hz at 1 MHz offset at 62 GHz and an output power of -20 dBm. The VCO including buffers dissipates in the dual-core operation mode 60 mA from a single 1.1 V supply and consumes a chip area of 0.58 mm2.
CRIS-Team Scopus Importer:2023-03-08
Keywords: Active circuits; Oscillators

A 52-to-67 GHz Dual-Core Push-Push VCO in 40-nm CMOS - Issakov, Vadim; Rimmelspacher, Johannes; Trotta, Saverio; Tiebout, Marc; Hagelauer, Amelie Marietta; Weigel, Robert (European Microwave Conference, 2017)
We present a continuously tunable 52-to-67 GHz push-push dual-core voltage-controlled oscillator (VCO) in a 40 nm bulk CMOS technology. The circuit is suitable for 60 GHz FMCW radar applications requiring a continuously tunable ultra-wide modulation bandwidth. The LC-tank inductor is used to couple the two VCO cores. The fundamental frequency of the VCO can be tuned from 26 GHz to 33,5 GHz, which corresponds to a frequency tuning range (FTR) of 25%. The second harmonic is extracted in a non-invasive way using a transformer. The primary side acts simultaneously as a second harmonic filter. The VCO achieves in measurement a low phase noise of 91,8 dBc=Hz at 1 MHz offset at 62 GHz and an output power of 20 dBm. The VCO including buffers dissipates in the dual-core operation mode 60 mA from a single 1,1 V supply and consumes a chip area of 0,58 mm2.
Keywords: millimeter-wave; ultra-wideband; CMOS technology

A 5V, 20MHz Bandwidth, fully differential Operational Amplifier with 70 V/μs Slew Rate and 205 ns/30 ns enable/disable time in 180 nm CMOS - Mai, Timo; Weigel, Robert (IEEE International Symposium on Industrial Electronics, 2020)
When the enable-pin of an Opamp is used for modulation, or it is powered down due to power consumption considerations, the turn-on and turn-off time delay are critical [6]. Here we present a differential Opamp that works as differential amplifier. It uses adaptive biasing in common mode feedback circuit and power stages. It has a slewrate of 70 V/μs, an on-delay of 205 ns and an off-delay of 30 ns. To the best of our knowledge, the latter is the fastest ever published. It is fabricated in 180 nm CMOS with 1.04xl.26mm chip area and draws 9mA out of 5V.
CRIS-Team Scopus Importer:2020-08-28
Keywords: adaptive biasing; gain boosting; monticelli; operational amplifier; process variations

A 60 GHz 30.5% PAE Differential Stacked PA with Second Harmonic Control in 45 nm PD-SOI CMOS - Ciocoveanu, Radu; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2019)
This paper presents a 60GHz highly efficient single-stage differential stacked Class AB power amplifier (PA) with second harmonic control. The circuit has been realized in a 45 nm PD-SOI CMOS technology. Measurement results show that the power amplifier achieves a maximum output power (Pmax) of 15.3dBm with a competitive maximum power-added efficiency (PAEmax) of 30.5% at 60 GHz. The output-referred 1-dB compression point (OP1dB) is 9.5 dBm. Furthermore, the circuit draws 40mA from a 1.8V supply and the chip core size is 0.36mm x 0.35 m
Keywords: Power Amplifier; High-Power; High-Efficiency; PD-SOI.

A 60-GHz Integrated Radar Transmitter with Multiple Frequency Inputs and Digital Adjustable Gain in a 130-nm BiCMOS Technology - Völkel, Matthias; Schrotz, Albert-Marcel; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE Radio and Wireless Symposium, 2019)
In this paper a 60 GHz monolithic transmitter for high precision based industrial radar systems is presented. The integrated transmitter has been designed using a 0.13μm SiGe BiCMOS process from IHP (SG13G2) and includes multiplier, multiplexer, power amplifier and a digital interface. For testing, a PCB interface adapter is developed to control and supply the chip directly on the wafer prober. The integrated transmitter circuit has a size of 1800μm x 1600μm and a maximum power consumption of 148.5mW from a 3.3V power supply. The circuit provides four frequency inputs and multiplies them up to 60 GHz. The chip delivers a output power of 8dBm at 60GHz and min. 5dBm over a frequency range from 55 to 65 GHz. The input path is switched and the output power is adjustable by a digital interface between -20 and 8dBm at 60 GHz. This serial interface is realized in 0.13μm CMOS logic and consists of a 15 bit shift register, decoder and and analog interface.<br
Keywords: industrial radar; transmitter; millimeter wave circuits; SiGe BiCMOS

A 60-GHz Low-Noise Variable-Gain Amplifier in a 130-nm BiCMOS Technology for Sixport Applications - Völkel, Matthias; Dietz, Marco; Hagelauer, Amelie Marietta; Weigel, Robert; Kissinger, Dietmar (IEEE International Symposium on Circuits and Systems, 2017)
Abstract—A monolithic low noise variable gain amplifier (LNA) operating at 60 GHz is presented. It is designed for a sixport receiver, which is completely integrated on a single chip. These chips are build in highly miniaturized sensors to measure distances with radar. Therefore a high performance LNA is indispensable. The circuit has been designed using a new 0.13 m SiGe BiCMOS process from IHP (SG13G2). For implementation a three stage architecture is chosen. Measurements show a tuneable gain from 16 to 24 dB at 60 GHz, an input matching of -17 dB and an output matching of -14 dB. The circuit consumes 13mA from a 3.3V supply.

A 60 GHz Push-Push VCO in 45 nm RF-SOI CMOS Technology for Integrated Phased-Array Radar Applications - Rimmelspacher, Johannes; Weigel, Robert; Issakov, Vadim (PHAROS Event, 2018)
This paper presents a 60 GHz push-push voltage-controlled oscillator (VCO) for millimetre-wave (mm-wave) radar applications. The VCO is fabricated in a 45 nm partially-depleted (PD) RF silicon-on-insulator (RF-SOI) CMOS technology. The measured frequency tuning range (FTR) is 15% (56.6 – 65.7 GHz), lowest phase noise (PN) is −91.3 dBc/Hz at 1 MHz offset and the total DC power consumption is 68 mW for a 1 V supply voltage. The simulated core DC power consumption is 10 mW

A 60 GHz Push-Push Voltage-Controlled Oscillator with Adaptive Gate Biasing in 28 nm Bulk CMOS Technology - Rimmelspacher, Johannes; Hagelauer, Amelie Marietta; Weigel, Robert; Issakov, Vadim (International Microwave Symposium 2018, 2018)

A 62 GHz reflectometer for biomedical sensor readout in SiGe BiCMOS technology - Lämmle, Benjamin; Schmalz, Klaus; Scheytt, Christoph; Kissinger, Dietmar; Weigel, Robert (IEEE Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 2012)
elib2cris::1512001600,laemmle2012

A 6ps Resolution Pulse Shrinking Time-to-Digital Converter as Phase Detector in Multi-Mode Transceiver - Liu, Yue; Vollenbruch, Ulrich; Chen, Yangjian; Wicpalek, Christian; Maurer, Linus; Mayer, Thomas; Boos, Zdravko; Weigel, Robert (IEEE Radio and Wireless Symposium, 2008)
This paper presents a new phase detector in an all digital phase locked loop which converts the phase difference between one reference clock edge and one divided oscillator edge into a digital word. This digital word can be converted into a digital representation of the actual phase error which can be utilized in an all digital phase locked loop. 6 ps resolution for this time-to-digital converter (TDC) is realized in a standard 0.13 mum CMOS technology. Its full- scale-range (FSR) is 4500 ps.
elib2cris::1512001600,yue2008
Keywords: convertors; digital phase locked loops; oscillators; phase detectors; transceivers; CMOS technology; digital phase locked loop; multimode transceiver; oscillator edge; phase detector; pulse shrinking time-to-digital converter; size 0.13 mum; CMOS technology; Clocks; Gas detectors; Phase detection; Phase locked loops; Phase noise; Power generation; Radio frequency; Space technology; Transceivers; PLL; TDC; all digital PLL

A 70 GHz bandwidth low-power active balun employing common-collector resisitive feedback in 0.35 um bipolar SiGe technology - Radwan, Ahmed; Weigel, Robert; Kissinger, Dietmar (IEEE MTT-S International Microwave Symposium, 2014)
elib2cris::1512001600,gharib2014

A 70 to 90 GHz High-Linearity Multi-Band Quadrature Receiver in 0.35 μm SiGe Technology - Nasr, Ismail; Lämmle, Benjamin; Aufinger, Klaus; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE Transactions on Microwave Theory and Techniques, 2013)
An integrated frequency agile quadrature E-band receiver is presented in this paper. The complete receiver is realized in a commercial 0.35μm SiGe:C technology with an ft=fmax of 170/250GHz. The receiver covers the two point to point communication bands from 71 to 76 GHz and 81 to 86 GHz and the automotive radar band at 77 GHz. A wide tuning range modified Colpitts oscillator provides an LO tuning range > 30%. A two stage constant phase RC polyphase network is implemented to provide wide-band quadrature (IQ) LO signals. The measured phase imbalance of the network stays below 8 over the receiver’s frequency range. In addition the chip includes a wide-band LNA, Wilkinson power divider, down conversion mixers and frequency prescaler. Each of the chip’s receiver I/Q paths shows a measured conversion gain above 19 dB and an input referred 1 dB compression point of -22 dBm. The receiver’s measured noise figure stays below 11 dB over the complete frequency range. Furthermore, the receiver has a measured IF bandwidth of 6 GHz. The complete chip including prescaler draws a current of 230mA from a 3.3V supply, and consumes a chip area of 1628μm x 1528 μm.
elib2cris::1512001600,nasr2013b

A 77 GHz Direction of Arrival Detector System with SiGe Integrated Six-Port Receiver - Vinci, Gabor; Lämmle, Benjamin; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (Radio-Wireless Symposium, 2012)
In this publication the design of a 77 GHz Direction-Of-Arrival (DOA) detector system with an Integrated SiGe six-port receiver and a passive microstrip antenna network is presented. The introduction of the six-port receiver for industrial sensors and automotive radar applications has opened a whole new set of possibilities and implementations. A typical problem though of Millimeter-Wave (MW) integration is the interface between the on-chip circuitry and the off-chip system electronics or passives. The antenna design aspects and interconnections are presented with a layouting analysis as well as a system overview of the DOA detector for a flexible, low-complexity and low-cost solution in microstrip technology.
elib2cris::1512001600,vinci2012a
Keywords: Antenna measurements; Antennas; Automotive engineering; Detectors; Microstrip; Radar; Receivers

A 77-GHz Down-Conversion Mixer Architecture with Built-In Test Capability in SiGe Technology - Kissinger, Dietmar; Knapp, Herbert; Maurer, Linus; Weigel, Robert (Bipolar/BiCMOS Circuits and Technology Meeting, 2010)
A 77-GHz double-balanced mixer in a 200 GHz ft silicon-germanium technology is presented. The proposed mixer architecture is capable of simultaneous direct up- and down-conversion of two separate input signals without additional power consumption. An up-converted low-frequency test signal is coupled back into the receiver RF input path to enable a built-in functionality test of the down-conversion path of the mixer. The circuit exhibits a conversion gain of 20 dB and draws 22mA from a 3.3V supply. The fabricated chip occupies an area of 1028 × 1128μm2.
elib2cris::1512001600,kissinger2010d
Keywords: Frequency measurement; Impedance matching; Mixers; Power generation; Radio frequency; Receivers; Silicon germanium

A 77-GHz FMCW Radar Transceiver sourced through a 19 GHz SiGe Colpitts Oscillator - Starzer, Florian; Forstner, Hans-Peter; Wagner, Christoph; Fischer, A.; Jäger, Herbert; Kissinger, Dietmar; Stelzer, Andreas (Asia Pacific Microwave Conference, 2009)
elib2cris::1512001600,starzer2009

A 77 GHz SiGe Mixer Circuit with LO Active Frequency Multiplier for Automotive Radar - Hartmann, Marcus; Wagner, Christoph; Seemann, Kay; Jäger, Herbert; Kolmhofer, Erich; Weigel, Robert (Bipolar/BiCMOS Circuits and Technology Meeting, 2007)
This paper presents a direct-conversion mixer for 77 GHz integrated with an active 4times LO frequency multiplier. The circuit was manufactured using a SiGe technology. Noise figure, conversion gain, linearity and s-parameter measurement results will be shown.
elib2cris::1512001600,hartmann2007d

A 77 GHz SiGe mixer in an embedded wafer level BGA package - Wojnowski, Maciej; Engl, Mario; Dehlink, Bernhard; Sommer, Grit; Brunnbauer, M.; Pressel, Klaus; Weigel, Robert (ECTC, 2008)
elib2cris::1512001600,wojnowski2008

A 77-GHz Six-Port Receiver Front-End for High-Precision Angle-of-Arrival Detection - Lämmle, Benjamin; Vinci, Gabor; Maurer, Linus; Weigel, Robert; Kölpin, Alexander (IEEE Journal of Solid-State Circuits, 2012)
In this paper an integrated six-port receiver front-end for angle-of-arrival detection of 77-GHz signals is presented. Applications of the circuit are direction finding, automotive radar calibration, or high precision industrial radar. The measurement principle is based on passive superposition of two incident signals and power detection. The circuit features two input amplifiers, a broadband passive six-port network, and four power detectors. The integrated circuit has a power consumption of 95 mW with 5 V supply voltage. It is fabricated in a 200-GHz fT SiGe bipolar technology and occupies only 1028 × 1128 μm2. The circuit operates in a 3-dB bandwidth from 75 GHz to 84 GHz and has a responsivity of 152 kV/W at 80 GHz. A simple calibration method is proposed and all calibration parameters are calculated for different frequency values.
elib2cris::1512001600,laemmle2012b
Keywords: Antenna measurements; Bandwidth; Couplers; Detectors; Receivers; Radar; Frequency Measurement; bipolar integrated circuits; radio direction-finding; angle-of-arrival detection; automotive radar calibration; Six-Port

A 780-nW Frequency-Agile Fully Integrated Super-Regenerative Multi-Channel UHF Receiver for Continuous Spectral Monitoring - Eppel, Markus; Milosiu, Heinrich; Kögel, Tobias; Oehler, Frank (2019)
This paper proposes a frequency agile fully integrated super-regenerative receiver for spectral power estimation. A 180-nm implementation of the proposed receiver is presented with measurements.The receiver draws 26 mu A from a 1.8 Volt supply to scan 60 frequency points between 380 and 960 MHz every 1.8 ms, hence 780 nW per channel. The "resolution bandwidth" lies between 2 and 15 MHz, depending on the quench-signal. No external filter components are used. Filter quality factors greater than 400 are achieved, using an on-chip inductor. The best measured receiver sensitivity is -75 dBm.
Keywords: UHF; CMOS; integrated circuits; super regenerative receiver; spectrum analyzer; ultra-low power; UWB

A 900 MHz ladder-type SAW filter duplexer - Weigel, Robert; Weigenthaler, Klaus; Dill, Roland; Schropp, Isidor (Microwave Symposium Digest, 1996)
A low-cost hybrid-integrated SAW filter duplexer consisting of receiver top filter, transmitter final-stage filter and antenna terminal has been developed. The prototype design was oriented at the GSM system specifications in the 900 MHz-band. Three-stage ladder-type SAW filters have been designed to perform the duplexing function by the use of only one transmission line. The complete duplexer has an insertion loss of 1.2 dB in the Tx path (Tx) and 2.1 dB in the Rx path (Rx). The 3 dB-bandwidth is 40.1 MHz (Tx) and 47.4 MHz (Rx), respectively
elib2cris::1512001600,weigel1996d
Keywords: low; cost; hybrid; SAW; receiver; filter; GSM; transmisson

A 900 MHz SAW Microstrip Antenna-Duplexer for Mobile Radio - Anemogiannis, Kimon; Beck, Christian; Roth, Alexander; Russer, Peter; Weigel, Robert (IEEE MTT-S International Microwave Symposium Digest, 1990, 1990)
A novel, 900-MHz SAW (surface acoustic wave) microstrip antenna-duplexer designed for use in European mobile radio systems is presented. The duplexer consists of a transmitter SAW filter, two receiver SAW filters, a low-noise receiver amplifier, and a duplexing microstrip circuit. A dual-track filter design using interdigital transducers for track coupling provides low insertion loss (5 dB), small passband ripple (+or-0.5 dB), high stopband rejection (50 dB), and small chip-size (TO-39 package). The filters were fabricated on 36 degrees -rotated YX-LiTaO/sub 3/ substrates with a photolithographic technique. Due to the design of the microstrip duplexer, the selectivity of the front end is enhanced by 15 dB.<>
93781a41-0f22-4bbe-83c8-b30fb0ad65d3::1512001600,anemogiannis1990
Keywords: microstrip antennas; mobile radio systems; high stopband rejection; interdigital transducers; Low-noise amplifiers; Microstrip antennas; Microstrip filters; Mobile antennas

A 9.7 mW 0.13 um CMOS PLL for Use in 24 GHz Sensor Nodes - Jung, Melanie; Ferizi, Alban; Ußmüller, Thomas; Fischer, Georg; Weigel, Robert (IEEE International Midwest Symposium on Circuits and Systems, 2011)
elib2cris::1512001600,jung2011a

A 9-Channel Phase Coherent Receive System for Direction of Arrival Estimation - Depold, Andreas; Dorn, Christian; Erhardt, Stefan; Weigel, Robert; Lurz, Fabian (European Microwave Week 2021, 2022)
Collapsed buildings are a common occurrence after earthquakes, but are also commonly caused by gas explosions. The survival chance of buried victims is heavily dependent on the time it takes to locate and rescue them. This paper introduces a 9-channel phase coherent receive system intended for direction finding in search and rescue applications. The motivation for this system is to minimize the time necessary to locate the buried phones of victims. The design consists of an FPGA based digital system with high speed I/O for data acquisition and signal processing, as well as nine synchronized receivers each covering the entire target bandwidth. A high phase resolution is achieved down to very low input level

A 9th-Order Continuous Time Sigma-Delta-ADC with X-Coupled Differential Single-Opamp Resonators - Zeller, Sebastian; Münker, Christian; Weigel, Robert (IEEE International Midwest Symposium on Circuits and Systems, 2011)
Continuous time Sigma-Delta-ADCs are usually designed with noise transfer functions containing conjugate complex zeros to extend the usable bandwidth. Traditionally, these zeros are implemented with a resonance generated by feedback around two integrator opamps.
elib2cris::1512001600,zeller2011a
Keywords: continuous time systems; differential amplifiers; integrating circuits; operational amplifiers; poles and zeros; conjugate complex zeros

A Bandwidth Efficiency Optimized Frequency Domain Equalization Concept for Single Carrier Transmission - Witschnig, Harald; Stallinger, H.; Huemer, Mario (Lecture Notes in Computer Science, 2007)
The concept of Single Carrier Transmission with Frequency Domain Equalization (SC/FDE) represents one of the most powerful strategies for next generation wireless communication systems. One of the main advantages of this concept, which makes use of a so called cyclic prefix (CP), is its powerful and low complexity equalization procedure in frequency domain. In this paper we investigate frequency domain equalization schemes based on the more bandwidth efficient concepts of Overlap and Add (OA) and Overlap and Save (OS). We explore the main problem of these approaches, namely the difficult predefinition of a maximum equalizer length, and we present a solution which results in a bit error performance absolutely comparable to the CP based equalizer.
elib2cris::1512001600,witschnig2007

A Bayesian Framework for Integrated Deep Metric Learning and Tracking of Vulnerable Road Users Using Automotive Radars - Dubey, Anand; Santra, Avik; Fuchs, Jonas; Lübke, Maximilian; Weigel, Robert; Lurz, Fabian (IEEE Access, 2021)
With the recent advancements in radar systems, radar sensors offer a promising and effective perception of the surrounding. This includes target detection, classification and tracking. Compared to the state-of-the-art, where the state vector of classical tracker considers only localization parameters, this paper proposes an integrated Bayesian framework by augmenting state vector with feature embedding as appearance parameter together with localization parameter. In context of automotive vulnerable road users (VRUs) such as pedestrian and cyclist, the classical tracker poses multiple challenges to preserve the identity of the tracked target during partial or complete occlusion, due to low inter-class (pedestrian-cyclist) variations and strong similarity between intra-class (pedestrian-pedestrian). Subsequently, feature embedding corresponding to target’s micro-Doppler signature are learned using novel Bayesian based deep metric learning approaches. The tracker’s performance is optimized due to a better separability of the targets. At the same time, the classififiers’ performance is enhanced due to Bayesian formulation utilizing the temporal smoothing of the classififier’s embedding vector. In this work, we demonstrate the performance of the proposed Bayesian framework using several vulnerable user targets based on a 77 GHz automotive radar.
Keywords: Automotive Radar; Bayesian Framework; Deep Metric learning; Integrated Classification-Tracking; Unscented Kalman Filter

A Bidirectional 28 GHz RF Transceiver Front-End with Test and Calibration Interface for 5G Phased Arrays - Kolb, Katharina; Potschka, Julian; Maiwald, Tim; Aufinger, Klaus; Hagelauer, Amelie; Dietz, Marco; Weigel, Robert (2021 16TH EUROPEAN MICROWAVE INTEGRATED CIRCUITS CONFERENCE (EUMIC 2021), 2021)
CRIS-Team WoS Importer:2022-09-09

A Bidirectional 28 GHz RF Transceiver Front-End with Test and Calibration Interface for 5G Phased Arrays (to be published) - Kolb, Katharina; Potschka, Julian; Maiwald, Tim; Aufinger, Klaus; Hagelauer, Amelie; Dietz, Marco; Weigel, Robert (European Microwave Integrated Circuits Conference (EuMIC), 2022)

A Binary Time Series Model of LTE Scheduling for Machine Learning Prediction - Ah Sue, Jonathan; Hasholzner, Ralph; Brendel, Johannes; Kleinsteuber, Martin; Teich, Jürgen (1st International Workshops on Foundations and Applications of Self-Adaptive and Self-Organizing Systems (SASO 2016)Self-Organizing Systems (SASO 2016), 2016)

A Broadband 10-95 GHz Variable Gain Ampliﬁer in a 130 nm BiCMOS Technology - Bauch, Andreas; Dietz, Marco; Weigel, Robert; Hagelauer, Amelie Marietta; Kissinger, Dietmar (European Microwave Integrated Circuits Conference, 2017)

A broadband 1.33 THz GBP 120-mW common-collector feedback amplifier in SiGe technology - Radwan, Ahmed; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE Bipolar/BiCMOS Technology and Devices Meeting, 2012)
elib2cris::1512001600,gharib2012

A broadband 24 GHz bandwidth 54 dB gain 180-mW amplifier employing common-collector combinded with capacitive controlled cross-coupled feedback in 0.35 um SiGe technology - Radwan, Ahmed; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE Bipolar/BiCMOS Circuits and Technology Meeting, 2013)
elib2cris::1512001600,gharib2013

A Broadband 3-29 GHz Reflectometer with a Frequency Compensated Multilayer Sixport Structure - Trenz, Florian; Hofmann, Maximilian; Weigel, Robert; Kissinger, Dietmar (2015 European Microwave Week, 2015)
In this paper, a planar broadband sixport reflectometer structure is presented. A frequency range from 3 to 29 GHz could be achieved by merging broadband components into a single multilayer pcb stackup with an area of 66x55 mm2 . The reflectometric architecture used herein allows a frequency independent q-point configuration of the sixport by implementing microstrip linelength compensation. Broadband matching of around -10 dB could be reached at all ports in a frequency range from 1 to 30 GHz. Acceptable coupling from DUT port to measurement output could be reached in a range from 2 to 29 GHz. Frequency compensation of the structure and an optimal q-point constellation of 120-120-120 have been verified by measurement. Due to its broadband functionality, compactness and cost efficiency, the proposed system is suitable for a wide range of microwave measurement applications.
elib2cris::1512001600,trenz2015
Keywords: Reflectometry; sixport; Microwave circuits; broadband

A Broadband Zero-IF Down-Conversion Mixer in 130 nm SiGe BiCMOS for Beyond 5G Communication Systems in D-Band - Maiwald, Tim; Potschka, Julian; Kolb, Katharina; Dietz, Marco; Visweswaran, Akshay; Weigel, Robert; Hagelauer, Amelie (IEEE Transactions on Circuits and Systems II: Express Briefs, 2021)

Absorption line strengths of 15 NH3 in the near infrared spectral region - Lins, Bastian; Pflaum, Felix; Engelbrecht, Rainer; Schmauß, Bernhard (Applied Physics B-Lasers and Optics, 2011)
UnivIS-Import:2015-03-09:Pub.2011.tech.IE.LEH.absorp

Abstimmbare Anpassnetzwerke auf Basis ferroelektrischer Varaktoren für Mobilfunkanwendungen - Schmidt, Matthias (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2008)

A Burst Phase Analysis Technique for High Precision Time Delay Estimation of Frequency Hopping GSM Signals - Götz, Alexander; Rose, Richard; Zorn, Stefan; Fischer, Georg; Weigel, Robert (Asia-Pacific Microwave Conference (APMC), 2011)
In this paper, a novel burst phase analysis technique for high precision time delay estimation of frequency hopping GSM signals is presented. The technique makes use of the increased bandwidth of frequency hopping waveforms and acquires and processes the signals in a coherent way. This way, the actual applicable bandwidth for time delay estimation and localization purposes is increased significantly. In case of E-GSM 900 systems, up to 35 MHz of bandwidth can be used which enables localization of mobile phones in the order of a few meters. The technique is therefore ideally suited for search and rescue applications. The presented method may also be applied to TETRA, DECT, IEEE 802.15.4 (ZigBee) or IEEE 802.15.1 (Bluetooth) signals.
elib2cris::1512001600,goetz2011b
Keywords: GSM; TDOA; Localization; Frequency Hopping

A Cascadable Integrated Bistatic Six-port Transceiver at 60 GHz in a 130-nm BiCMOS Technology for SIMO-Radar Applications - Völkel, Matthias; Pechmann, Stefan; Hussein, Eissa Mohamed; Kissinger, Dietmar; Weigel, Robert; Hagelauer, Amelie Marietta (APMC, 2019)
In this paper a 60 GHz cascadable bistatic integrated interferometric transceiver for SIMO radar applications is presented. The integrated transceiver has been designed in a 0.13μm SiGe BiCMOS technology (SG13G2) from the institute innovations for high performance microelectronics (IHP). The System includes a 15 GHz buffer stage, a low noise amplifier, a passive interferometric six-port structure, several detectors and amplifiers as well as a digital interface. The chip has a size of 2.75mm x 1.15mm and a maximum power consumption of 525mW from a 3.3V power supply. The 15 GHz frequency input is multiplied to reach a 60 GHz signal at a minimum input power of -40 dBm. The chip delivers a maximum output power of 10.2 dBm. A digital interface adjusts the output power between -22 and 10,2 dBm at an output frequency of 60 GHz. The reference input power of the six-port and the RF input power could be adjusted in a range of 13.2 dB. The maximum P1dB is at -24.1 dBm. The measured power detector sensitivity is 7090 V/W. The standard deviation of the phase measurement is 0.025 rad.<br
Keywords: bistatic; industrial radar; integrated transceiver; interferometric radar; millimeter wave circuits; SIMO Radar; MMIC; SiGe BiCMOS; six-port; system-on-chip (SoC)

Access Network Evolution Beyond 3G Mobile Communications - Huemer, Mario (IEEE/OEVE International Workshop on W-CDMA RF-Issues and Future Trends, 2002)
elib2cris::1512001600,huemer2002

Accuracy bounds and measurements of a contactless permittivity sensor for gases using synchronized low-cost mm-wave frequency modulated continuous wave radar transceivers - Och, Andreas; Schrattenecker, Jochen O.; Schuster, Stefan; Hölzl, Patrick A.; Freidl, Philipp F.; Scheiblhofer, Stefan; Zankl, Dominik; Weigel, Robert (Sensors, 2019)
A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. This paper examines the performance limits of low-cost frequency-modulated continuous-wave (FMCW) radar sensors for permittivity measurements. First, the accuracy limits are investigated theoretically and the Cramér-Rao lower bounds for time-of-flight based permittivity and concentration measurements are derived. In addition, Monte-Carlo simulations are carried out to validate the analytical solutions. The capabilities of the measurement concept are then demonstrated with different binary gas mixtures of Helium and Carbon Dioxide in air. A low-cost time-of-flight sensor based on two synchronized fully-integrated millimeter-wave (MMW) radar transceivers is developed and evaluated. A method to compensate systematic deviations caused by the measurement setup is proposed and implemented. The theoretical discussion underlines the necessity of exploiting the information contained in the signal phase to achieve the desired accuracy. Results of various permittivity and gas concentration measurements are in good accordance to reference sensors and measurements with a commercial vector network analyzer (VNA). In conclusion, the proposed radar-based low-cost sensor solution shows promising performance for the intended use in demanding industrial applications.
CRIS-Team Scopus Importer:2019-08-20
Keywords: Cramér-Rao bounds; Gas detectors; Millimeter wave radar; Permittivity; Phase estimation; Radar measurements; Time of arrival estimation

Accuracy Considerations and FMCW Operation of a Six-Port Device - Stelzer, Andreas; Diskus, Christian; Weigel, Robert (IEEE Asia Pacific Microwave Conference, 2001)
The application of a six-port device in a frequency modulated continuous wave sensor system is presented. Two completely different modes of operation are combined in the distance sensor to achieve an outstanding performance. A frequency sweep is accomplished and evaluated using the uncalibrated six-port device without degrading the final distance accuracy. The obtained distance accuracy is determined by the phase measurement accuracy of the calibrated six-port operating at 35 GHz. Influences of the six-port parameters with respect to the phase accuracy are treated
elib2cris::1512001600,stelzer2001e
Keywords: FMCW; SIX-PORT

Accurate and Efficient Modeling of SAW Structures - Hofer, M.; Jungwirth, Mario; Lerch, Reinhard; Weigel, Robert (Frequenz, 2001)
elib2cris::1512001600,hofer2001
Keywords: Surface acoustic wave; Modeling

Accurate Broadband RLCG-Parameter Extraction with TRL Calibration. - Wojnowski, Maciej; Engl, Mario; Sommer, Grit; Weigel, Robert (Automatic RF Techniques Group (ARFTG) Conference, 2008)
elib2cris::1512001600,wojnowski2008a

Accurate Characterization of Microstrip Filter and Hybrid-Ring Coupler via an Improved TLM Method USing Variable and Curved Meshes - Isele, Bertram; Bender, Harald; Weigel, Robert; Hausner, Josef; Russer, Peter (21st European Microwave Conference, 1991, 1991)
A microstrip circuit design tool based on the two-dimensional transmission-line matrix (2D-TLM) method is described. The TLM algorithm described in this paper incorporates variable and curved discretization meshes and fast Fourier transform (FFT) with zero-padding. Numerical results have been computed for two planar configurations, an 11th order low-pass filter with a design cut-off frequency of 6.6 GHz, and a four-port 3 dB hybrid-ring coupler with a design center frequency of 12 GHz. These circuits were fabricated in hardboard thin-film technology (Â¿ = 9.9), and measurements made with an HP8510 network analyzer were compared with our TLM results, other theoretical analysis, and commercial software data. We found that the 2D-TLM results are in close agreement with generalized scattering matrix analysis and with experimental results.
elib2cris::1512001600,isele1991
Keywords: Circuit synthesis; Coupling circuits; Cutoff frequency; Fast Fourier transforms; Low pass filters; Microstrip filters; Software measurement; Thin film circuits; Transmission line matrix methods; Transmission lines

Accurate Design of Low-Noise Microwave SAW Oscillators - Eichinger, Ludwig; Sischka, S.; Olbrich, Gerhard; Weigel, Robert (IEEE International Ultrasonics Symposium, 2000)
elib2cris::1512001600,eichinger2000

Accurate Modeling of microacoustic Strip Waveguide on Anisotropic Substrate in Terms of Electromagnetic Ray Zigzagging - Weigel, Robert (Proc. Progress in Electromagnetics Research Symposium, 1995)
elib2cris::1512001600,weigel1995b

Accurate optical measurement of surface acoustic wave phase velocity - Weigel, Robert; Holm, Andreas; Russer, Peter; Ruile, Werner; Soelkner, Gerald (IEEE Ultrasonics Symposium, 1993)
A high-resolution technique for the optical detection of the phase and amplitude of high frequency surface acoustic waves (SAW's) is presented. The test setup incorporates a mode-locked picosecond laser, harmonic mixing, and coherent detection, and it allows not only the measurement of the surface wave field but also the direct determination of the phase velocity. A measurement bandwidth in excess of 2 GHz is achieved. The maximum scan length was 4 cm. As a substrate, LiNbO3 has been used for the test measurements. Minimum detectable surface displacement and dynamic range were 1 pm/Hz1/2 and 40 dB, respectively. The method enables the determination of the phase velocity with a resolution of 1.5·10-5 in dependence of crystal cut, temperature and frequency
elib2cris::1512001600,weigel1993l

Accurate Power Loss Measurements of Aperture Tuning RF Switches on Board - Solomko, Valentyn; Özdamar, Oguzhan; Rimmelspacher, Johannes; Nascimento, Pablo; Muerke, Michael; Pyo, Chul Seung; Weigel, Robert; Hagelauer, Amelie (2021 IEEE ASIA-PACIFIC MICROWAVE CONFERENCE (APMC), 2021)
CRIS-Team WoS Importer:2022-05-20

Accurate Prediction of Dispersion and Attenuation of Long Metal Strip SAW Waveguides on Anisotropic Substrate - Schropp, Isidor; Reindl, Leonhard; Grassl, Hans-Peter; Weigel, Robert (Proc. IEEE Ultrasonics Symposium, 1988, 1988)
As a design tool for high-precision long broadband SAW (surface acoustic wave) delay lines, a computationally simple model for strip waveguides has been improved by inclusion of parametric fits to measured anisotropy, dispersion, and attenuation of Rayleigh wave propagation both on free and metallized surfaces of LiNbO3. A heuristic approach was used to account for the effect of anisotropy in the case of an imaginary transverse propagation constant, and for the observed increased attenuation in waveguides compared to unbounded surfaces. The model does not rely on material properties as computed from fundamental material constants, and uses only one adjustable parameter which is not directly obtained from surface wave measurements. The phase nonlinearly can be predicted with an accuracy up to ±0.5°/μs over a relative bandwidth on the order of 50%
null::1512001600,schropp1988
Keywords: acoustic waveguides; lithium compounds; strip lines; surface acoustic wave devices; ultrasonic delay lines; Acoustic waveguides; Attenuation; Surface waves

A CDMA Modulation Technique for Automotive Time-of-Flight LiDAR Systems - Fersch, Thomas; Weigel, Robert; Kölpin, Alexander (IEEE Sensors Journal, 2017)
We present the application of optical code division multiple access (OCDMA) modulation based on optical orthogonal codes for automotive time-of-flight light detection and ranging (LiDAR) system sensors using avalanche photodiode (APD) detectors. The modulation opens the possibility to discriminate single laser transmissions. This allows the realization of additional features like enhancing the systems’ interference robustness or accelerating their scanning rate. The requirements on automotive LiDAR OCDMA modulation differs from telecommunication’s demands in several ways: The sensor must guarantee absolute laser safety; front facing devices must be able to provide reliable long range results up to a distance of 150m and beyond; and the signal is transmitted through free space. After outlining the basic functionality of the sort of sensors in consideration, the properties of the optical orthogonal codes (OOC) modulation are compared with the state of the art theoretically. The influence of OOC parameters with respect to scanning LiDAR systems is examined. The modulation technique is then demonstrated experimentally with two examples: The detection and separation of coded and traditional signals is shown using a matched filter detection algorithm. In the same way, differently coded signals can be separated from each other. Impediments of the interference suppression quality are discussed. Finally, an overview of possible applications of the proposed technique in automotive LiDAR systems is given, which are enabled by the OCDMA modulation in the first place.
elib2cris::1512001600,fersch2017
Keywords: LiDAR; CDMA

A Chargepump with enhanced Current Matching and reduced Clock-Feedthrough in Wireless Sensor Nodes - Jung, Melanie; Ferizi, Alban; Weigel, Robert (Asia Pacific Microwave Conference, 2010)
Today, most of the locating systems are based on phase-locked loop (PLL) architectures for synthesizers. The synthesizer as a key element for location accuracy needs a chargepump with an exact current matching for improved phase noise performance. Especially in indoor scenarios, where sensor nodes must reach a precision below a few centimeters, the fidelity of the synthesizer system is important. This paper addresses the design of a chargepump with enhanced current matching and reduced clock-feedthrough in a FMCW based sensor node. The difference between a conventional chargepump design and the enhanced design is presented and compared to show the current matching improvement and clock-feedthrough reduction. The different designs were manufactured in a 0.13μm CMOS process by IBM. They are running in a PLL with 128MHz reference frequency and have an output current of 100μA with a total power consumption of 1mW for the chargepump with phase-frequency detector (PFD).
elib2cris::1512001600,jung2010a
Keywords: Clocks; Phase frequency detector; Phase locked loops; Transconductance; Transistors; Wireless communication; Wireless sensor networks

A Chip-Area-Efficient Baseband Processing Core for FMCW Radar-based Sensor Network Localization - Ferizi, Alban (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

A chirp-based wideband spread spectrum modulation technique for WLAN applications - Gugler, Wolfgang; Springer, Andreas; Weigel, Robert (IEEE Sixth International Symposium on Spread Spectrum Techniques and Applications, 2000)
A high data-rate wideband chirp spread spectrum system for indoor communications is presented. We propose the use of chirp signals with the well known pulse compression technique to make the system extremely robust and therefore suitable for applications in an industrial environment. By using π/4-DQPSK modulation of the chirp signals, overlapping chirp signals, and optimized chirp signal design we achieve data rates up to 70 Mbps. There is no need for sophisticated digital signal processing due to the use of surface acoustic wave (SAW) filters for the generation and filtering of the chirp signals. System imperfections like production tolerances, temperature drift, nonlinearities, and others are shown to be either negligible or can be easily handled. Simulation results reveal that the limiting factor for the data rate is intersymbol interference caused by multipath propagation
elib2cris::1512001600,gugler2000a
Keywords: wideband; WLAN

A circuit technique to compensate PVT variations in a 28 nm CMOS cascode power amplifier - Oßmann, Patrick; Fuhrmann, Jörg; Moreira, José; Pretl, Harald; Springer, Andreas (German Microwave Conference (GeMiC), 2015)

A Class-E GSM-Handset PA with Increased Efficiency - Koller, Rainer; Stelzer, Andreas; Abt, Karl-Heinz; Springer, Andreas; Weigel, Robert (33rd European Microwave Conference, 2003, 2003)
Today's GSM handset PA implementations give lots of room for efficiency improvement due to the fact that especially in the power-backoff region most of the consumed input power provided by the handset battery is dissipated as heat. This reduces the maximum talking time significantly and makes utilization of smaller batteries impossible. Switching amplifiers provide by default the highest possible efficiency while their drawbacks, such as narrow bandwidth and low linearity, do not apply to the GSM system due to the used modulation scheme, GMSK. In this paper, a demonstrator for GSM handsets is presented. Using Class-E amplification, it provides the necessary output power of 2W at an efficiency far beyond present solutions while maintaining the GSM specifications. Furthermore, concepts for efficient power control of this amplifier are proposed.
elib2cris::1512001600,koller2003
Keywords: Batteries; Circuit simulation; Frequency; GSM; Power amplifiers; Power generation; Power harmonic filters; Switches; Switching circuits; Telephone sets

A Classification and Comparative Overview of State-of-the-Art Analog Linearization Techniques for Integrated CMOS Power Amplifiers - Zohny, Amr; Rascher, Jochen; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (IEEE International Conference on Wireless Information Technology and Systems - ICWITS 2012, 2012)
In order to conform to the latest mobile communication standards, highly-linear power amplifiers (PA) are required. This is a challenge since high power added efficiency (PAE) is also needed for long battery life which dictates operating close to saturation where amplitude and phase nonlinearities are dominant. Thus linearization is necessary to simultaneously improve average efficiency and linearity [1]. Traditional linearization techniques such as feedback and feedforward suffer from bandwidth limitations and efficiency degradation respectively. Furthermore, digital predistortion (DPD) techniques are integrable albeit suffering from high system complexity [2]. State-of-the-art analog linearization techniques however solve many of these problems. The aim of this paper is to propose a classification of these techniques as shown in section II. In addition, section III shows a comparative overview of these techniques. Utilizing that classification and comparative study, the proper deep submicron (DSM) CMOS on-chip linearization techniques for handsets are then identified for modern communication standards.
elib2cris::1512001600,zohny2012a
Keywords: Power Amplifier; Linearity; PAE; CMOS; Predistortion

A Class of Jointly Power and Bandwidth Efficient Digital Modulation Schemes for Single Carrier Transmisson with Frequency Domain Equalization - Buzid, Tufik; Reindl, Leonhard; Huemer, Mario (International Symposium on Signals, Systems and Electronics, 2004)
elib2cris::1512001600,buzid2004

A Clinically Evaluated Interferometric Continuous-Wave Radar System for the Contactless Measurement of Human Vital Parameters - Michler, Fabian; Shi, Kilin; Schellenberger, Sven; Steigleder, Tobias; Malessa, Anke; Hameyer, Laura; Neumann, Nina; Lurz, Fabian; Ostgathe, Christoph; Weigel, Robert; Kölpin, Alexander (Sensors, 2019)
Vital parameters are key indicators for the assessment of health. Conventional methods rely on direct contact with the patients’ skin and can hence cause discomfort and reduce autonomy. This article presents a bistatic 24 GHz radar system based on an interferometric six-port architecture and features a precision of 1 µm in distance measurements. Placed at a distance of 40 cm in front of the human chest, it detects vibrations containing respiratory movements, pulse waves and heart sounds. For the extraction of the respiration rate, time-domain approaches like autocorrelation, peaksearch and zero crossing rate are compared to the Fourier transform, while template matching and a hidden semi-Markov model are utilized for the detection of the heart rate from sphygmograms and heart sounds. A medical study with 30 healthy volunteers was conducted to collect 5.5 h of data, where impedance cardiogram and electrocardiogram were used as gold standard for synchronously recording respiration and heart rate, respectively. A low root mean square error for the breathing rate (0.828 BrPM) and a high overall F1 score for heartbeat detection (93.14%) could be achieved using the proposed radar system and signal processing.

A clock synchronization for M-sequence-based ultra-wideband systems - Hamouda, Mohammed; Guarin Aristizabal, Gustavo Adolfo; Gardill, Markus; Lämmle, Benjamin; Weigel, Robert; Kissinger, Dietmar; Ußmüller, Thomas (IEEE Transactions on Microwave Theory and Techniques, 2014)
elib2cris::1512001600,hamouda2014c

A CMOS divider family for high frequency wireless localization systems - Jung, Melanie; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (International Semiconductor Conference Dresden - Grenoble (ISCDG), 2012)
elib2cris::1512001600,jung2012

A CMOS Image Sensor with Analog Pre-Processing Capability Suitable for Smart Camera Applications - Söll, Christopher; Shi, Lan; Bänisch, Andreas; Ußmüller, Thomas; Weigel, Robert (IEEE International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS), 2015)
This work presents a novel CMOS sensor which is suitable for analog image processing operations and describes the benefits of analog pre-processing over digital algorithms. All needed modifications to read out a spatial NxN pixel matrix simultaneously are presented regarding pixel wiring, row decoder and column multiplexer as well as descrambling the order of the outputs. The outputs are connected via a buffer stage to the analog pre-processing circuits. As an example for such an analog computation, an averaging filter is described from design constraints to the actual implementation. Simulation results show a very low current consumption of just 55.3 μA under worst-case conditions and a computation time below 200 ns. This corresponds to a power-time product ratio of 1:18.75 compared to a digital state-of-the-art implementation.
elib2cris::1512001600,soell2015b
Keywords: Smart Cameras; CMOS Image Sensors; Analog Processing Circuits; Filtering Algorithms; GRK-1773

A CMOS quad-band-sigma-delta-transceiver for GSM-EDGE with dual mode transmitter architecture for low noise and high linearity - Simon, Martin; Weigel, Robert; Neurauter, Burkhard; Märzinger, Günther (Radio Frequency Integrated Circuits (RFIC) Symposium, 2004)
A 120 nm CMOS quad-band transceiver for GSM EDGE with a dual mode transmitter architecture and a constant gain direct conversion receiver has been developed. In GMSK mode, a direct conversion transmitter with third order ΣΔ-modulation loop modulates the phase of the VCO. The output signal is amplified by a low noise power efficient limiting output buffer with 6 dBm output power. A high linearity vector modulator is switched on to process the 8-PSK modulated EDGE signal with additional amplitude modulation. Neither TX-SAW nor third harmonic filter are needed for system integration into a handset to fulfil the GSM-EDGE specification.
elib2cris::1512001600,simon2004

A CMOS RF Front-End IC for Multi Antenna Diversity Applications in the S-Band - Hartmann, Christian; Rascher, Jochen; Weigel, Robert; Fischer, Georg; Ußmüller, Thomas (19th International Conference on Microwaves, Radar and Wireless Communications (MIKON), 2012)
In recent years the reception of audio broadcast signals via satellite has become popular, especially in the United States with the SDARS-system, supplying high quality broadcast services in particular to customers with mobile usage scenarios like in cars. There, the problem of reception impairments due to multipath wave propagation in urban areas or influences from dense foliage of the surrounding vegetation affects the broadcast quality. A possibility to minimize signal interruptions and to enhance the reception quality is the application of fast switchable multi antenna diversity receivers. In this paper we present the concept of an integrated RF front-end IC for such a system and describe the design of several important building blocks. The circuits are implemented in a 150nm CMOS technology from LFoundry in Landshut, Germany.
elib2cris::1512001600,hartmann2012a

A cognitive system for future‐proof wireless microphones: Concept, Implementation and Results - Brendel, Johannes; Rieß, Steffen; Weigel, Robert; Fischer, Georg (11th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services (TELSIKS), 2013)
Since several years, 'cognitive radio' is given much attention in research and is seen as a future technology in communications. In this paper a cognitive radio system for Program Making and Special Event (PMSE) devices (e.g. wireless microphones) is presented and the results of a field test are discussed. First, we outline the challenges which the PMSE industry has to cope with and how changes in regulatory and the digital dividend in the TV UHF band has impact on the operation reliability of PMSE devices. Afterwards, a system using cognitive radio techniques to ensure the high audio quality requirements and interference free operation of PMSE devices under the previously mentioned circumstances is presented. Beside a general overview over the developed system we focus on a distributed spectrum sensing network as part of the cognitive information acquisition to monitor the current spectrum situation. The data is used by the cognitive engine to detect potential interferers and to trigger operation parameter changes (e.g. frequency or transmit power) of the PMSE devices to avoid link quality degradation. We present the built up sensor nodes for the spectrum measurement and the developed software to control the sensor nodes and to preprocess the measured data. Finally, the results, collected with the field test platform in the fairgrounds of Berlin, show convincingly how the developed cognitive system makes PMSE devices future‐proof.
elib2cris::1512001600,brendel2013a

A Combination of a Digital Foreground and Background Calibration for a 16Bit and 200MS/s Pipeline Analog-to-Digital Converter - Löhr, Robert; Stadelmayer, Markus; Röber, Jürgen; Ohnhäuser, Frank; Weigel, Robert (ECCTD, 2017)
High-Performance Analog-to-Digital Converter (ADC) have high requirements concerning sampling rate and linearity. Therefore a new formula is derived to determine, which pipeline stage dependent on the used capacitor sizes needs to be calibrated for the targeted linearity. Furthermore, a model of a 16 bit and 200MS/s pipeline ADC is described. A combination of a digital foreground and a digital background calibration is presented, which can compensate linear errors and achieves a DNL smaller than ±1 and a THD of -88 dB.
Keywords: Pipeline ADC; modeling; common mode jump; capacitor-flip-over architecture; digital calibration; foreground; background; high resolution.

A Combined Galileo/GPS Receiver Architecture for Consumer Market Applications - Schmid, Andreas; Neubauer, André; Ehm, Henning; Weigel, Robert; Heinrichs, Günther; Lemke, Norbert; Avila-Rodriguez, Jose-Angel; Pany, Thomas; Rohmer, Günther; Nagel, Peter (2nd ESA Workshop on Satellite Navigation User Equipment Technologies (NAVITEC 2004), 2004)
elib2cris::1512001600,schmid2004a

A Compact Analog Active Time delay Line using SiGe BiCMOS Technology - Hamouda, Mohammed; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (IEEE International Symposium on Circuits and Systems, 2013)
This work discusses the design of a 60ps delay element for UWB analog signals ranging from 0.05 up to 7.5GHz. The design is implemented using BJT transistors which have the advantage of being very compact in area compared to the passive architectures. The proposed architecture is flexible and can be cascaded to have delay upto 210ps with 3dB insertion loss. The circuit is designed using low cost 0.25μm 95GHz fmax SiGe-HBTBiCMOS process technology consuming a power of 121mW. The estimated consumed area of the circuit is 560μm x 870μm.
elib2cris::1512001600,hamouda2013a
Keywords: ultra wide band; delay; m-sequence

A Compact Back-Plaster Sensor Node for Dementia and Alzheimer Patient Care - Schwarzmeier, Andre; Besser, J.; Weigel, Robert; Fischer, Georg; Kissinger, Dietmar (2014 IEEE Sensors Applications Symposium (SAS 2014), 2014)
Abstract— This paper presents a compact and highly integrated back-plaster sensor node equipped with seamless localization (in-door and out-door) using assisted GPS and bluetooth localization, activity classification and fall detection as well an GSM module providing a GPRS connection to a server infrastructure for supporting dementia and Alzheimer patients within their daily life. The innovative and durable design as a hermetic rubber-sealed, waterproof and sanitizable back-plaster ensures optimum wearing comfort for the patient as well as reliable fall-detection. In addition with an internet server infrastructure the described plaster sensor node allows to inform relatives or professional care staff in case of an emergency and help to enhance the quality of life by increasing the sense of feeling secure.
elib2cris::1512001600,schwarzmeier2014
Keywords: Index Terms— remote health monitoring; medical information system; fall-detection; localization; sensor processing; data fusion

A Compact Energy-Saving D-Band Frequency Quadrupler with -1 dB Conversion Gain in 22 nm FDSOI - Engelmann, Andre; Probst, Florian; Hetterle, Philip; Weigel, Robert (Asia-Pacific Microwave Conference, 2024)
This work presents a compact and energy-saving D-band frequency multiplier by 4 (quadrupler) integrated into an advanced 22nm fully-depleted silicon-on-insulator (FDSOI) technology. The circuit consists of a multi-phase driven two-stage push-push doubler architecture achieving a conversion gain of -1 dB and covers a bandwidth of 23 GHz centered at 133 GHz. At 0.8V supply voltage, the quadrupler attains a maximum output power of -3.4dBm and an efficiency of 1.71% while consuming only 27mW of DC power. A harmonic rejection greater than 26 dBc is reached over the entire bandwidth. The core cell of the circuit occupies a compact chip area of 325x250 μm2.<br
https://cris.fau.de/converis/publicweb/Publication/311361348
Keywords: CMOS; D-band; FDSOI; frequency multiplier; MMIC; quadrupler; signal generation

A compact medical platform for mobile sensor fusion and data communication - Agethen, Roman; Reuter, Lukas Michael; Lurz, Fabian; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE International Workshop on Medical Measurements and Applications (MeMeA), 2011)
elib2cris::1512001600,agethen2011

A Compact Multi-Layer Analog Front-End of a Six-Port Receiver - Kölpin, Alexander; Winter, Sebastian; Weigel, Robert (23rd Annual Review of Progress in Applied Computational Electromagnetics, 2007)
The focus of this work lies on a new compact layout of the analog front-end of a six-port receiver. One drawback of this receiver architecture is its large physical dimension, which makes it hard to fabricate it as a monolithic microwave circuit (MMIC). In this paper the theoretical aspects of the system concept will be shown and a new folded multi-layer layout of the passive analog structure will be presented. The new design is compared to the classic planar layout.
elib2cris::1512001600,koelpin2007
Keywords: six-port; multi-layer

A Compact, Versatile Six-Port Radar Module for Industrial and Medical Applications - Linz, Sarah; Vinci, Gabor; Mann, Sebastian; Lindner, Stefan; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (Journal of Electrical and Computer Engineering, 2013)
The Six-port receiver has been intensively investigated in the last decade to be implemented as an alternative radar architecture. Plenty of current scientific publications demonstrate the effectiveness and versatility of the Six-port radar for special industrial, automotive and medical applications, ranging from accurate contactless vibration analysis, through automotive radar calibration to remote breath and heartbeat monitoring. Its highlights, such as excellent phase discrimination, trivial signal processing, low circuit complexity and cost have lately drawn the attention of companies working with radar technology. A joint project involving the University of Erlangen-Nuremberg and InnoSenT GmbH (Innovative Sensor Technology), led to the development of a highly accurate, compact and versatile Six-port radar module aiming at a reliable high-integration of all subcomponents such as antenna, Six-port front-end, baseband circuitry and digital signal processing in one single package. Innovative aspects in the RF front-end design as well as in the integration strategy are hereby presented, together with a system overview and measurement results.
elib2cris::1512001600,linz2013b

A Compact, Versatile Six-Port Radar Sensor for Industrial and Medical Applications - Linz, Sarah; Vinci, Gabor; Lindner, Stefan; Mann, Sebastian; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (IEEE Sensors, 2013)
The Six-Port receiver can be implemented as an alternative radar architecture. Plenty of current scientific publications demonstrate the effectiveness and versatility of the Six-Port radar for industrial, automotive and medical applications: accurate contactless vibration analysis, distance measurements as well as remote breath and heartbeat monitoring. Its highlights are excellent phase discrimination, trivial signal processing, low circuit complexity and cost. A joint project involving the University of Erlangen-Nuremberg and InnoSenT GmbH led to the development of iSYS-5001, a compact, versatile Six-Port radar module aiming at a reliable high-integration of all subcomponents in one single sensor unit.
elib2cris::1512001600,linz2013a

A Comparative Overview of High Power Handling CMOS Switches and their Recent Applications in RF Front-Ends - Rascher, Jochen; Zohny, Amr; Glock, Stefan; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (14th Annual Wireless and Microwave Technology Conference (WAMICON), 2013)
In this publication techniques for high power handling capability (PHC) of RF switches in bulk CMOS are investigated and compared. Together with high isolation approaches these allow reconfigurable power amplifiers (PAs) or radio front-ends for Watt level communication standards. Special care is taken to assess the applicability of the solutions for monolithic integration in scaled CMOS processes. Results are shown with PHC as high as 34dBm in a 32nm CMOS process. Recent applications for the switches in front-ends or reconfigurable PAs are analyzed. They show large DC current reduction in back-off with stage bypassing and load adaptation concepts. Up to 50% DC current reduction for low output power is reported. This greatly improves the average PA efficiency for varying envelope signals without the efforts of more advanced solutions like envelope tracking.
elib2cris::1512001600,rascher2013

A Comparative Study of Different Types of Piezoelectric Interface Circuits to Perform Simultaneous Sensing and Energy Harvesting - Gogoi, Niharika; Zhu, Yuanjia; Zhang, Gufei; Fischer, Georg (2023)
This article presents a comparison of 4 different types of rectifier circuits for piezoelectric energy harvesting. Energy is harvested from multiple piezoelectric elements embedded in an in?sole while simultaneously collecting gait information of the subject wearing it. The study is based on an asymmetric signal generated while walking and the harvested energy is utilized to operate a system under a fixed electrical load. The influence of back-up battery and insole design optimization on the accuracy of collected information is taken into consideration. A comprehensive approach for shoe insole application based on simultaneous piezoelectric sensing and energy harvesting is presented in this work.<br

A Comparison of an OFDM System and a Single Carrier System Using Frequency Domain Equalization. - Witschnig, Harald; Huemer, Mario; Koppler, Alois; Springer, Andreas; Weigel, Robert (European Transactions on Telecommunications, 2002)
In this work we compare an OFDM (Orthogonal Frequency Division Multiplexing) system and a SC/FDE (Single Carrier System with Frequency Domain Equalization) system in terms of their BER performance, channel estimation techniques, bandwidth- fficiency and other design parameters. In both systems an estimation of the channel transfer function is needed for equalization purposes. Different frequency domain based channel estimation techniques for both systems are presented and compared. BER- simulations have been performed for channel-coded data in typicd indoor multipath environments. The parameters of both systems are adapted to the Hiperlad and IEEE 802.1 la standards. It will be pointed out that OFDM shows slight advantages when taking the BER performance into account, while the SC/FDE system exhibits advantages in terms of signal processing complexity. Finally a combination of OFDM and SC/FDE is described that exhibits significant advantages.
elib2cris::1512001600,witschnig2002a
Keywords: OFDM; Equalization

A Comparison of Channel Access Concepts for High-Precision Local Positioning - Mosshammer, Ralf; Waldmann, Benjamin; Eickhoff, Ralf; Huemer, Mario; Weigel, Robert (6th Workshop on Positioning Navigation and Communication, 2009)
elib2cris::1512001600,mosshammer2009b

A Comparison of Complex Curve Fitting and Subspace Identification Algorithm for Circuit Modeling Using Frequency Domain Data - Neumayer, Roland; Stelzer, Andreas; Weigel, Robert (33rd European Microwave Conference, 2003, 2003)
Efficient transient simulation of complex structures or components characterized by frequency-domain network parameters is of great interest in microwave theory. In this paper, two different model extraction techniques for broadband linear network characterization are discussed. A parametric complex curve fitting technique and a frequency-domain subspace identification algorithm are applied to generate passive circuit models for microwave devices characterized by measured frequency-domain port response data. By means of practical examples both methods are evaluated regarding usability, accuracy and CPU time.
elib2cris::1512001600,neumayer2003g
Keywords: Character generation; Frequency domain analysis; Data mining; Curve fitting; Circuit simulation; Microwave devices; Microwave theory and techniques; Passive circuits; Microwave measurements; Microwave generation

A Comparison of CPW-to-CPS Fed Ultra Wideband Antennas - Oßberger, Gerald; Buchegger, Thomas; Stelzer, Andreas; Diskus, Christian; Weigel, Robert (International Workshop on Ultra Wideband Systems (IWUWBS 2003), 2003)
elib2cris::1512001600,ossberger2003
Keywords: antenna; CPW; CPS; ultra wideband

A comparison of OFDM and non-linear SC/FDE signals: Non-linear amplification - Buzid, Tufik; Reinhardt, Steffen; Huemer, Mario (11th European Wireless Conference, 2005)
One of the most influential parameters in today's wireless communications market is the battery lifetime, especially for mobile devices. In contrast to OFDM (Orthogonal Frequency Division Multiplexing), Sc/FDE ( single carrier transmission with frequency domain equalization) allows to apply signal formats with constant envelope, such as CPM (C ontinuous Phase Modulations) or at least significantly lower Peak to Average Power Ratios (PAPRs) such as Offset-QPSK. This allows the signal to drive the power amplifier into its maximum power efficient region. As a consequence the batteries lifetime is extended and its size is reduced. In this work, we compare non-linear modulated, block-oriented SC/FDE signals with OFDM signals in terms of bit error rate and spectrum disturbances at the non-linear region of the power amplifier.
elib2cris::1512001600,buzid2005
Keywords: OFDM; SC/FDE

A Comparison of State-of-the-Art Efficiency Enhancement Techniques of Fully Integrated CMOS Power Amplifiers for Handset LTE Applications - Zohny, Amr; Rascher, Jochen; Weigel, Robert; Ußmüller, Thomas (International Conference on Wireless Information Technology and Systems, 2013)
Among the significant remaining challenges of complete transceiver integration for handset applications is the implementation of high-efficiency power amplifiers (PA) in CMOS. This challenge is exacerbated by the high crest factors of the signals utilized in WCDMA and LTE standards. The first aim of this paper is to identify the shortcomings of the traditional efficiency enhancement techniques in dealing with LTE in CMOS. In addition, an investigation of state-ofthe- art implemented efficiency enhancement methods is performed. Moreover, a comparative overview of the aforementioned techniques is presented to provide guidelines for high-efficiency CMOS LTE PA. This is accomplished while identifying the bottlenecks for the future LTE upgrades. Finally, the performances of the investigated techniques for CMOS are compared with other technologies to assay the commercial suitability of CMOS PA for LTE.
elib2cris::1512001600,zohny2013
Keywords: Power amplifier; Power-added efficiency; linearity; CMOS; long-term evolution; peak-to-average power ration

A comparison of tunable ferroelectric Π- and T-matching networks - Schmidt, Matthias; Lourandakis, Errikos; Leidl, Anton; Seitz, Stefan; Weigel, Robert (European Microwave Conference, 2007)
A comparison of tunable pi - and T-matching networks based on ferroelectric capacitors is presented. Both topologies are promising candidates for automated antenna tuners in mobile communication systems. Assets and drawbacks of both circuits are discussed comparing linear and nonlinear simulations and measurements of two exemplary circuits at 850 MHz. The requirements to achieve sufficient linearity are determined by means of simulations. Both matching networks cover an impedance range of approximately |Gammain| les 0.6 with a maximum transducer power loss of 4 dB and 6 dB, respectively.
elib2cris::1512001600,schmidt2007

A Compensation Method for Relative Movement Between A Sensor Array and the Abdomen for Magnetic Localization of Capsule Endoscopes - Zeising, Samuel; Schneider, Alexander; Thalmayer, Angelika; Fischer, Georg; Kirchner, Jens (IEEE Transactions on Instrumentation and Measurement, 2022)

A Computationally Optimized Method for Joint DC Offset and Channel Estimation - Deutsch, Gerhard; Krüger, Martin; Springer, Andreas; Weigel, Robert (Austrochip 2003, 2003)
This paper presents a fast version of the in [1] introduced algorithm for simultaneous channel tap and DC offset estimation. To start, we breifly review the basic approach from [1]. By decomposing its structure we obtain a mathematically equivalent fast method, which requires only roughly 50% memory usage and computational power compared to the original work. We conclude, focusing complexity comparisons of the two methods, promoting the novel approach.
elib2cris::1512001600,deutsch2003a
Keywords: Optimized; DC Offset; Channel Estimation; memory usage; computational power; complexity comparison; GSM; EDGE

A Contactless System for Continuous Vital Sign Monitoring in Palliative and Intensive Care - Shi, Kilin; Will, Christoph; Steigleder, Tobias; Michler, Fabian; Weigel, Robert; Ostgathe, Christoph; Kölpin, Alexander (2018 Annual IEEE International Systems Conference (SysCon), 2018)
Vital sign monitoring systems play a crucial role in the medical environment. Patients in palliative and intensive care can especially benefit from continuous observation by detecting sudden changes in health status allowing the medical staff to promptly provide intensified symptom amelioration at the end-of-life. However, machine based monitoring like electrocardiography requires the patient being permanently wired to the device. This circumstance severely restricts the independence and mobility of the patient, leading to a decrease in the quality of life. For this reason, palliative care stations currently usually avoid continuous monitoring. After a comprehensive literature survey and background research, this paper presents a novel approach by using a single radar system to perform continuous and above all contactless monitoring of respiration and heartbeat. A continuous wave radar using the Six-Port technology is introduced and its feasibility, performance and real-time capability are validated in long-term measurements on different test persons. In comparison to gold standard reference devices a correlation of 97.6% was achieve

A Continuously Adjustable True Time Delay for D-Band Timed Antenna Arrays - Koch, Manuel; Probst, Florian; Breun, Sascha; Weigel, Robert (2023 18th European Microwave Integrated Circuits Conference, EuMIC 2023, 2023)
This paper presents a fully integrated true time delay (TTD) circuit for beamforming applications based on the delay sum principle operating at a center frequency of 144 GHz with a 3 dB bandwidth of 26 GHz. It features a measured delay range of 1.75 ps whose resolution is only limited by the integrated digital-to-analog converter (DAC). A demonstrator has been manufactured in a 130 nm bipolar complementary metal-oxide-semiconductor (BiCMOS) technology, occupying 0.53 × 0.3mm 2 of chip area including serial peripheral interface (SPI), bandgap reference and four DAC
CRIS-Team Scopus Importer:2023-12-01
Keywords: BiCMOS integrated circuits; delay lines; phase shifters

A Coplanar Transmission Line High-T/sub c/ Superconductive Oscillator at 6.5 GHz on a Single Substrate - Klieber, Ralf; Ramisch, Roland; Valenzuela, Alejandro; Weigel, Robert; Russer, Peter (IEEE Microwave and Guided Wave Letters, 1992)
The design and construction of a planar, low-noise cryogenic oscillator operating at 6.5 GHz are presented. The oscillator has been built as a hybrid superconductive microwave integrated circuit (SMIC) on a single 10*10 mm LaAlO/sub 3/ substrate. Single-sided, coplanar line structures are used throughout the circuit with YBa/sub 2/Cu/sub 3/O/sub 7- delta / as conductor material. The oscillator was constructed around a GaAs MESFET as the active device. The complete oscillator is cooled by immersion in liquid nitrogen. An output power of 4.9 dBm was obtained. Single-sided noise power at 10 kHz offset from carrier was -90 dBc/Hz.<>
elib2cris::1512001600,klieber1992
Keywords: barium compounds; Conducting materials; Coplanar transmission lines; Microwave oscillators; single substrate; SHF; MESFET; GaAs

A Coplanar Waveguide Resonator Based In-Line Material Characterization Sensor for Bulk and Metallized Dielectrics - Talai, Armin; Gold, Gerald; Frank, Martin; Mann, Sebastian; Weigel, Robert; Kölpin, Alexander (Frequenz, 2016)
Microwave Materials such as Rogers RO3003 are subject to process-related fluctuations in terms of the relative permittivity and dielectric loss. The behavior of high frequency circuits like patch-antenna arrays and their distribution networks is dependent on the effective wavelength. Therefore, fluctuations of the complex permittivity will influence the resonance frequency and beam direction of the antennas. This paper presents a grounded coplanar waveguide based sensor, which can measure the complex permittivity at 77 GHz, as well as at other resonance frequencies, by applying it on top of the manufactured depaneling. The relative permittivity of the material under test (MUT) is a function of the resonance frequency shift and the dielectric loss of the MUT can be determined by transmission amplitude variations at the resonances. In addition, the sensor is robust against floating ground metallizations on inner printed circuit board layers, which are typically distributed over the entire surface below antennas. Furthermore, the impact from conductor surface roughness on the measured permittivity values is determined using the Gradient Mode
lhft_intern.bib::talai2016a

A cost-efficient 61 GHz high-resolution radar sensor for industrial positioning and distance measurement - Wibbing, Sascha; Mann, Sebastian; Lurz, Fabian; Erhardt, Stefan; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (21st International Conference on Microwave, Radar and Wireless Communications (MIKON), 2016)
In this paper a novel 61GHz radar sensor node for industrial positioning and distance measurement is presented. The sensor provides numerous functions enabling a broad range of signal processing technologies and is designed with regard to cost-efficient implementation only using commercial available components without limiting the area of possible applications. Beside the requirement analysis and system design, several measurements of antenna isolation and distance resolution are depicted and discussed.
elib2cris::1512001600,wibbing2016a

A Cross Correlation Based Clock Synchronization up to 10GHz for Ultra-Wideband Sensing Systems - Hamouda, Mohammed; Lämmle, Benjamin; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (IEEE International Microwave Symposium, 2014)
This paper presents a cross correlation based synchronization architecture between the clock of the receiver and the transmitter for ultra-wideband radio systems. The designed architecture is based on M-sequence signals instead of the conventional impulse signals. The M-sequence generator and the analog correlation circuit are fabricated on chip using a low cost 0.25μm 95GHz fmax SiGe-HBT-BiCMOS process technology. The chip is mounted on a printed circuit board (PCB) with a commercial voltage controlled oscillator. The measurement results show a low phase noise of the VCO of -66dBc/Hz at 1KHz offset and an rms jitter of 1.6ps for a 10GHz frequency and a bit rate of 20Gb/s.
elib2cris::1512001600,hamouda2014b
Keywords: UWB

A cross polarized antenna with reflector based on electromagnetic bandgap (EBG) material - Dehm-Andone, Gunther; Wansch, Rainer; Gerhäuser, Heinz; Weigel, Robert; Kölpin, Alexander (IEEE Metamaterials 2011: The Fifth International Congress on Advanced Elec-tromagnetic Materials in Microwaves and Optics, 2011)
In this paper a gain improved cross polarized dipole antenna based on a Mushroom-Jerusalem-Cross hybrid electromagnetic bandgap (MJCH-EBG) structure is presented. For low frequencies these structures behave like metal surfaces. For a specific bandwidth at higher frequencies, that has to be dimensioned, they are highly resistive and represent a perfect magnetic conductor. This effect can be used to realize reflectors and to suppress surface waves at antennas. This helps to miniaturize these kind of antennas. Design, simulation, measurement and analysis is performed for this antenna at 10.7GHz
elib2cris::1512001600,dehm-andone2011
Keywords: electromagnetic bandgap; cross polarization; surface wave suppression; reflector

Activity Based High Level Modeling of Dynamic Switching Currents in Digital IC Modules - Gstöttner, Andreas; Steinecke, Thomas; Huemer, Mario (International Zurich Symposium on Electromagnetic Compatibility, 2006)
Electromagnetic compatibility (EMC) becomes an increasingly important subject within the IC design process, because more and more market segments demand for low electromagnetic emission (EME) of integrated circuits. Therefore automatic emission model generation tools need to become part of the design flow. In this paper we present an automatic generation procedure of equivalent current sources (ECS) from chip netlists, based on an analytic approach. The ECSs describe the dynamic switching currents of digital function blocks of complex ICs. Worst case or typical current profiles are not generated by pattern simulation, but by pre-characterized logic cells and a set of configuration parameters like switching activity
elib2cris::1512001600,gstoettner2006

A customizable UHF RFID-Reader for RFID-S Testing Applications - Hofmann, Andreas; Brenk, Daniel; Boehme, Andreas; Cilek, Fatih; Ferizi, Alban; Weigel, Robert (IEEE Topical Conference on Wireless Sensors and Sensor Networks, 2011)
This paper describes a custom-built UHF RFID-Reader-Device with functionality to send and receive EPCglobal custom commands. It can be used to access enhanced capabilities in transponders, for example readout of integrated sensors. The device was implemented using a Xilinx FPGA and is fully controllable from a PC through a customizable MATLAB-Interface. This enables a step by step test of newly developed tags. All mandatory EPCglobal commands are implemented as well as EPC custom command capability.
elib2cris::1512001600,hofmann2011
Keywords: Graphical user interfaces; Protocols; Radiation detectors; Radiofrequency identification; Software; Transceivers

A custom lightweight UAV for radar remote sensing: Concept design, properties and possible applications - Schütz, Martin; Oesterlein, Martin; Birkenhauer, Christoph; Vossiek, Martin (2017 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM 2017), 2017)
In this paper, we introduce a novel, tailor-made UAV-based sensor platform for radar remote sensing. It is controlled by a redundantly implemented, customized flight control and equipped with a comprehensive embedded system for radar baseband processing. Both systems are synchronized with a common, low-phase noise and temperature-stable reference clock, which allows coherent acquisition and continuous recording of sensor data. A commercial differential GPS system is used for positioning. The platform potentially allows interferometric remote sensing with synthetic apertures. In a first case study, it is equipped with a bistatic 24GHz MIMO radar system to create a side-looking-airborne-radar, allowing full interferometric SAR processing. As a proof-of-concept, a radar altimeter measurement is presented, which replaces and outperforms common altitude estimators, such as barometric or ultra sonic sensor

Adapting HMMS of distant-talking asr systems using feature-domain reverberation models - Sehr, Armin; Gardill, Markus; Kellermann, Walter (17th European Signal Processing Conference, EUSIPCO 2009, 2009)
To capture the dispersive effect of reverberation by Hidden Markov Model (HMM)-based distant-talking speech recognition systems, adapting the means of the current HMM state based on the means of the preceding states has been suggested in [1]. In this contribution, we propose to incorporate the reverberation models of [2] into the adaptation approach to describe the effect of reverberation with higher accuracy. Connected-digit recognition experiments in three different rooms confirm that the suggested more accurate reverberation representation leads to a significant performance increase in all investigated environments. © EURASIP, 200

Adaptive Automobilfunksysteme - Franchi, Norman; Fischer, Georg; Weigel, Robert (Embedded Software Engineering Kongress, 2013)
Traditionell werden in der Automobilbranche bis dato Systeme mit ausschließlich dedizierten, integrierten Chiplösungen, die jeweils nur auf einen Kommunikationsstandard spezialisiert sind, entwickelt. Im Gegensatz dazu wird in diesem Beitrag ein wegweisendes Integrations- und Prototypingkonzept, aufbauend auf dem Software-Defined-Radio-Prinzip, vorgestellt bei dem eine frei programmierbare Kommunikationsplattform eine Vielzahl unterschiedlicher Funkstandards auf ein und derselben Hardware abbilden kann. Ob diese Funkplattform nun verkehrstelematische Dienste (z.B. eCall-Notruffunktion, Car-2-X-Kommunikation) oder bspw. eine Mobilfunkanbindung (UMTS, LTE) ermöglicht, wird allein durch die Konfiguration der eingebetteten Software und digitalen Schaltkreise festgelegt. Am Beispiel der WLAN-Funkstandards IEEE 802.11b/p sollen anhand eines Demonstrators sowohl die Stärken des Prototypingkonzepts als auch des universellen Funkplattformansatzes für Funksysteme im Fahrzeug verdeutlicht werden.
elib2cris::1512001600,franchi2013c
Keywords: Software Defined Radio; Wireless Vehicular Communication Systems; Car-to-X; IEEE 802.11p

Adaptive Echtzeit-Drahtloskommunikation für den Test von Automobilsystemen - Kloc, Matej (Verlag Dr. Hut, 2018)
Die Komplexität von automobilen Steuergeräten und Systemen nimmt stetig zu. Um den immer größer werdenden Funktionsumfang abzusichern und die steigenden Anforderungen an Sicherheit, Zuverlässigkeit, Komfort und Umweltverträglichkeit zu erfüllen, werden leistungsfähige und zuverlässige Testlösungen, z.B. auf Basis von Hardware-in-the-Loop (HIL), benötigt. Aufgrund dessen wird in dieser Arbeit ein innovatives, leistungsfähiges Punkt-zu-Punkt-Kommunikationssystem vorgestellt, das eine drahtlose, bidirektionale Echtzeitübertragung von zeitkritischen Kontroll-, Diagnose- und Kalibrierdaten (KoDiKa) zwischen einem HIL-Testsystem und einem Steuergerät oder Bussystem (z.B. FlexRay) mit niedrigen Zykluszeiten von bis zu 1 ms ermöglicht. Dieser Ansatz eröﬀnet neuartige, mobile Testmöglichkeiten z.B. auf Teststrecken. Zunächst wird hierzu ein Konzept des drahtlosen Echtzeit-Gateways (DEGs) präsentiert, welches auf dem ﬂexiblen Software Deﬁned Radio-Ansatz (SDR) und der Bitübertragungsschicht nach WLAN-Standard IEEE 802.11p basiert. Dieser einzigartige DEG-Transceiver ermöglicht einen gleichzeitigen Betrieb auf mehreren Übertragungskanälen. Die daraus resultierende spektrale Agilität des DEGs verbessert den für die zyklische KoDiKa-Nutzdatenübertragung erforderlichen deterministischen Spektrumzugriﬀ in unlizenzierten Frequenzbändern trotz des verpflichtenden Listen-before-Talk-Verfahrens. Die Leistungs- und Echtzeitfähigkeit dieses Konzepts wird anschließend mit Hilfe von MATLAB-Simulationen evaluiert und charakterisiert. Dabei wird speziell anhand einer einzigartigen Koexistenzuntersuchung auf Grundlage von gemessenen Interferenzsignalen im unlizenzierten 2,4 GHz-Frequenzband gezeigt, dass die geforderte KoDiKa-Paketübertragungszuverlässigkeit sowie die Nutzdatenrate von 99% und 2 Mbit/s in einem mehrkanaligen DEG-Betrieb trotz durch koexistent operierende Drahtlosgeräte verursachten Interferenzen sichergestellt werden können. Weiterhin wird im Rahmen dieser Arbeit ein SDR-Prototyp des konzipierten DEGs unter Verwendung der agilen SDR-Plattform Nutaq ZeptoSDR, bei dem die gesamte digitale Basisbandsignalverarbeitung des DEGs ressourceneffizient in einem FPGA implementiert ist, gezeigt. Auf Grundlage dieses SDR-Prototypen wird zum einen die Realisierbarkeit des DEG-Transceivers demonstriert. Zum anderen wird ergänzend zu den MATLAB-Simulationen die Verbesserung der KoDiKa-Paketübertragungszuverlässigkeit in einem zweikanaligen DEG-Betrieb nachgewiesen.

Adaptive Ground Clutter Removal lgorithm for Ground Penetrating Radar Applications in Harsh Environments - Oßberger, Gerald; Buchegger, Thomas; Schimbäck, Erwin; Pfeil, R.; Stelzer, Andreas; Weigel, Robert (Sensing and Imaging, 2006)
elib2cris::1512001600,ossberger2006
Keywords: Ground Penetrating Radar

Adaptive IP2 calibration scheme for direct conversion receivers - Dufrene, Krzysztof; Weigel, Robert (Radio and Wireless Symposium, 2006)
This paper presents a novel even order intermodulation distortion cancellation scheme based on adaptive digital calibration of the RF downconversion mixer. The system, designed for an on-chip implementation, utilizes a low-complexity LMS-based equalizer. Behavioral and circuit level simulations indicate the feasibility of the approach.
elib2cris::1512001600,dufrene2006c
Keywords: Analog integrated circuits; DC offset; IP2; Mismatch; radio receivers; second-order distorsion

Adaptive phased array with full Polarisation agility for TV satellite reception - Fischer, Georg (COST-245, 1995)

Adaptive Signal- und Kanalemulation mit softwaredefinierter Funktechnik für IEEE-802.11p-basierte Car-2Car-Kommunikation - Franchi, Norman (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)

Adaptive Strategies for Enhancing the Efficiency of Radio Frequency Power Amplifiers in Back-Of Operation - Pinarello, Sandro (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2017)

A dataset of clinically recorded radar vital signs with synchronised reference sensor signals - Schellenberger, Sven; Shi, Kilin; Steigleder, Tobias; Malessa, Anke; Michler, Fabian; Hameyer, Laura; Neumann, Nina; Lurz, Fabian; Weigel, Robert; Ostgathe, Christoph; Kölpin, Alexander (Scientific Data, 2020)
Using Radar it is possible to measure vital signs through clothing or a mattress from the distance. This allows for a very comfortable way of continuous monitoring in hospitals or home environments. The dataset presented in this article consists of 24 h of synchronised data from a radar and a reference device. The implemented continuous wave radar system is based on the Six-Port technology and operates at 24 GHz in the ISM band. The reference device simultaneously measures electrocardiogram, impedance cardiogram and non-invasive continuous blood pressure. 30 healthy subjects were measured by physicians according to a predefined protocol. The radar was focused on the chest while the subjects were lying on a tilt table wired to the reference monitoring device. In this manner five scenarios were conducted, the majority of them aimed to trigger hemodynamics and the autonomic nervous system of the subjects. Using the database, algorithms for respiratory or cardiovascular analysis can be developed and a better understanding of the characteristics of the radar-recorded vital signs can be gaine
Keywords: Vital signs; Radar; Database; Reference signals

A dataset of radar-recorded heart sounds and vital signs including synchronised reference sensor signals. - Shi, Kilin; Schellenberger, Sven; Will, Christoph; Steigleder, Tobias; Michler, Fabian; Fuchs, Jonas; Weigel, Robert; Ostgathe, Christoph; Koelpin, Alexander (Scientific Data, 2020)
Radar systems allow for contactless measurements of vital signs such as heart sounds, the pulse signal, and respiration. This approach is able to tackle crucial disadvantages of state-of-the-art monitoring devices such as the need for permanent wiring and skin contact. Potential applications include the employment in a hospital environment but also in home care or passenger vehicles. This dataset consists of synchronised data which are acquired using a Six-Port-based radar system operating at 24 GHz, a digital stethoscope, an ECG, and a respiration sensor. 11 test subjects were measured in different defined scenarios and at several measurement positions such as at the carotid, the back, and several frontal positions on the thorax. Overall, around 223 minutes of data were acquired at scenarios such as breath-holding, post-exercise measurements, and while speaking. The presented dataset contains reference-labeled ECG signals and can therefore easily be used to either test algorithms for monitoring the heart rate, but also to gain insights about characteristic effects of radar-based vital sign monitoring.
EVALuna2:415941

A D-band transceiver front-end for broadband applications in a 0.35μm SiGe bipolar technology - Chakraborty, Abhiram; Trotta, Saverio; Wuertele, Johann; Weigel, Robert (Radio Frequency Integrated Circuits Symposium, 2014 IEEE, 2014)

A DC Adjustment Technique for High Offset Origin Suppression and Low Phase Error in GSM EDGE Transmitter. - Simon, Martin; Weigel, Robert (6th European Conference on Wireless Technology, 2003)
The system test of the Origin Offset Suppression in GSM EDGE systems requires high carrier suppression in a RF-transmitter with vectormodulation. This is difficult to achieve in integrated circuit design because of component mismatch and RF coupling inside the chip. The carrier feedthrough can be increased by adjusting the offset voltages in the mixer cells by the digital signal processor. A new mixer topology has been developed where the low frequency baseband signals can be measured with an analogue to digital converter directly before entering the RF circuits. The carrier suppression has been increased by more than 20 dBc after carrying out the adjustment algorithm due to the high accuracy of the circuit.
elib2cris::1512001600,simon2003a
Keywords: GSM; EDGE; Offset Origin Suppression; Transmitter; DC Adjustment; Phase Error

ADC Depending Limitations for Six-Port Based Distance Measurement Systems - Lindner, Stefan; Barbon, Francesco; Linz, Sarah; Lurz, Fabian; Mann, Sebastian; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2015)
This publication will show some considerations for selecting an appropriate analog-digital-converter (ADC) in Six-Port based radar systems for distance measurements. It will be discussed how the ADC resolution is limiting the overall system range resolution. Furthermore, configurations with non-synchronous sampling of the four baseband signals and their influences on the system performance will be investigated.
elib2cris::1512001600,lindner2015
Keywords: distance measurement; low-cost; radar; six-port; synchronous sampling; adc

A Deep Reinforcement Learning: Location-based Resource Allocation for Congested C-V2X Scenario - Bhadauria, Shubhangi; Vasan, Sneha; Roshdi, Moustafa; Roth-Mandutz, Elke; Fischer, Georg (2021 IEEE 12th Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON) (IEEE IEMCON 2021), 2021)
Cellular-Vehicle-to-Everything (C-V2X) communication as standardized in the 3rd generation partnership project (3GPP) plays an essential role in enabling fully autonomous driving. C-V2X envisions supporting various use-cases, e.g., platooning and remote driving, with varying quality of service (QoS) requirements regarding latency, reliability, data rate, and positioning. In order to ensure meeting these stringent QoS requirements in realistic mobility scenarios, an intelligent and efficient resource allocation scheme is required. This paper addresses channel congestion in location-based resource allocation based on Deep Reinforcement Learning (DRL) for vehicle user equipment (V-UE) in dynamic groupcast communication, i.e., without a V-UE acting as a group head. Using DRL base station acts as a centralized agent. It adapts the channel congestion due to vehicle density in resource pools segregated based on location in a TAPASCologne scenario in the Simulation of Urban Mobility (SUMO) platform. A system-level simulation shows that a DRL-based congestion approach can achieve a better packet reception ratio (PRR) than a legacy congestion control scheme when resource pools are segregated based on location.
Keywords: C-V2X communication; location based; resource allocation; congestion control; DRL

A Design-for-Sensitivity Strategy for Charge-Pump-Based Receivers - Schumacher, Tim; Fath, Patrick; Schmickl, Stefan; Faseth, Thomas; Hetterle, Philip; Weigel, Robert; Pretl, Harald (Proceedings - 2020 Austrochip Workshop on Microelectronics, Austrochip 2020, 2020)
This work presents the theoretical fundamentals of designing charge-pump-based receivers for maximum open-circuit voltage sensitivity (OCVS). From a classical Dickson charge pump with sub-zero-V_th transistors, various models are derived to extract correlation between specific parameters (e.g. number of stages, transistor widths and capacitor sizes) and the output voltage, maximum data rate and input impedance. This approach enabled us to develop an easily applied design strategy for this type of low-power receivers, which we demonstrate here for the 868MHz and 915MHz short-range-devices bands. It also considers an external matching network, our design strategy provides flexibility in layout generation and allows fast designing of receivers. Our strategy focuses on a rapid design flow rather than accurate representation, and is demonstrated using the example of a receiver design. In addition, the limitations of the derivations are discussed, and further optimizations are suggested.
CRIS-Team Scopus Importer:2020-12-04
Keywords: Charge-pump; design-Automation; matching; passive; receiver; SRD; wake-up

A dielectric lens antenna for digital beamforming and superresolution DOA estimation in 77 GHz automotive radar - Wenig, Peter; Weigel, Robert; Schneider, Martin (International ITG Workshop on Smart Antennas, 2008, 2008)
This paper introduces a novel dielectric lens antenna configuration for automotive radar applications. A cylindric lens fed by a uniform linear array (ULA) accomplishes elevation beam shaping and simultaneously allows for the application of digital beamforming (DBF) and superresolution DOA estimation methods in azimuth. Pattern perturbations due to lens edge effects are systematically analyzed. Finally guidelines for an optimum antenna setup with minimum sensor size are derived. The results show excellent elevation beam shaping performance. High resolution direction of arrival (DOA) estimation is important for future automotive safety systems. The concept has the potential for the application in a low cost automotive radar sensor that is expected to fulfill high DOA estimation requirements.
elib2cris::1512001600,wenig2008

A Differential 77-GHz Receiver with Current Re-Use Low-Noise Amplifier in SiGe Technology - Kissinger, Dietmar; Forstner, Hans-Peter; Jäger, Herbert; Maurer, Linus; Weigel, Robert (In: IEEE Topical Meeting on Silicon Monolithic Intergated Circuits in RF Systems (SiRF), 2010)
elib2cris::1512001600,kissinger2010
Keywords: Automotive engineering; Circuits; Gain; Germanium silicon alloys; Heterojunction bipolar transistors; Low-noise amplifiers; Manufacturing; Noise figure; radar; Silicon germanium

A Differential Pair based Direct Digital Synthesizer MMIC with 16.8 GHz Clock and 488 mW Power Consumption - Lämmle, Benjamin; Wagner, Christoph; Knapp, Herbert; Jäger, Herbert; Maurer, Linus; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2010)
This paper presents a low-power, high-speed direct digital synthesizer monolithic microwave integrated circuit in a SiGe bipolar technology with 8-bit phase and 6-bit amplitude resolution. The phase-to-amplitude mapping circuit is implemented as a differential pair in saturation. The use of a modern SiGe bipolar technology enables both a low power consumption of 488 mW at a 3.3-V supply and a high clock frequency of 16.8 GHz; here, the maximum output frequency is 8.3344 GHz and the frequency resolution is 65.625 MHz. A spurious-free dynamic range (SFDR) between 47-20 dBc is achieved. First Nyquist zone SFDR, narrowband SFDR, and frequency-modulation measurements of the signal are shown and discussed. The chip is fabricated in a 0.35-??m 200-GHz fT SiGe bipolar technology and occupies only 1128 ?? 1028 ??m2. The chip is mounted on a printed circuit board for measurement.
elib2cris::1512001600,laemmle2010a
Keywords: Ge-Si alloys; bipolar MMIC; clocks; direct digital synthesis; power consumption; Direct digital synthesizer (DDS)