An Approach to Over-the-air Synchronization of Commercial Chirp-Sequence Automotive Radar Sensors - Gardill, Markus; Schwendner, Johannes; Fuchs, Jonas (2020 IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNeT), 2020)
An approach to wireless synchronization between two commercial 77GHz automotive FMCW radar sensors is shown. Our focus is the alignment of a passive listening sensor to a second active transmitting sensor in frequency, time, and waveform modulation parameters, just by observing the signals transmitted from the active sensor. We show that using a combination of inter- and intra-chirpsequence synchronization, the active sensor’s signal can be successfully de-ramped for fast-chirp-sequence waveforms with 275MHz of bandwidth. In addition, we discuss timing requirements and challenges, and characterize the remaining synchronization errors by an analysis of the IF signal data matrix of the de-ramped wavefor

An area-efficient 130 nm CMOS baseband processing unit for 24 GHz FMCW radar positioning - Ferizi, Alban; Baust, Philipp; Jung, Melanie; Fischer, Georg; Weigel, Robert; Kölpin, Alexander (International Symposium on Signals, Systems, and Electronics (ISSSE), 2012)
This paper presents an area-efficient digital implementation of a baseband processing unit (BPU) for autonomous wireless sensor nodes with localization functionality. The presented wireless nodes should achieve a high miniaturization degree and use an onboard FMCW secondary radar for distance measurements. The challenge for designing the digital system was to reduce memory requirements towards a low cost hardware design in general, and for an ASIC design in particular. Reducing chip area implies lower energy consumption and helps saving implementation and production costs. At the same time a qualitative performance of the digital signal processing tasks while keeping the system constraints has to be assured. The introduced novel hardware implementation concept fulfill these criteria, and has been implemented and verified on a FPGA before starting the chip design. For the use case of a two-sweep-measurement-system the design has been realized as an ASIC using IBM 130nm CMOS technology.
elib2cris::1512001600,ferizi2012b
Keywords: Application specific integrated circuits; Baseband; Hardware; Radar; Random access memory; Wireless communication; Wireless sensor networks

An Area Efficient Low-Power mmWave PRBS Generator in FDSOI - Probst, Florian; Engelmann, Andre; Dietz, Marco; Issakov, Vadim; Weigel, Robert (IEEE MTT-S International Microwave Symposium 2022, 2022)
This paper presents an area efficient, low-power pseudo-random binary sequence (PRBS) generator which is built of true single-phase-clock (TSPC) flip-flops that form a linear-feedback shift register (LFSR). Operating at a supply voltage of 0.88 V it can generate a 2¹¹-1 m-sequence with a maximum data rate of 33 Gb/s. The circuit is fabricated in a 22-nm fully depleted silicon on insulator (FDSOI) CMOS technology and occupies a core area of only 42 μm2. With a core power consumption of only 1.3 mW at the maximum data rate, it is well suited for its application as a baseband signal generator in a phase-modulated continuous-wave (PMCW) radar transmitter. The PRBS generator exhibits a figure of merit (FoM) of only 8 fJ/bit which represents an improvement by the factor of five compared to the current state of the art to the best of authors’ knowledge.<br

An Automatic Detection and Data Downlink System for Miniature Bat Loggers - Erhardt, Stefan; Koller, Josef; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (IEEE Radio and Wireless Symposium (RWS) 2020, 2020)

An Automatic Gain and Offset Control Circuit for DC-Coupled Continuous-Wave Radar Systems - Michler, Fabian; Schönhärl, Stefan; Schellenberger, Sven; Shi, Kilin; Scheiner, Benedict; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (2020 IEEE/MTT-S International Microwave Symposium (IMS), 2020)

An automatic multi-level solver switching strategy for PEEC-based EMC simulation - Clees, Tanja; Samrowski, T.; Zitzmann, Martin-Ludwig; Weigel, Robert (18th International Zurich Symposium on Electromagnetic Compatibilit, 2007)
In this paper, we propose a new, efficient and robust automatic solver switching strategy, called α-SAMG, tailored to linear systems of equations arising in PEEC-based EMC simulation. The PEEC method (partial element equivalent circuit) is an approach for transforming conducting objects into linear networks with basic electrical elements. Such equivalent circuit models can be simulated by conventional circuit solvers such as SPICE (simulation program for integrated circuit emphasis) based on the MNA (modified nodal analysis) approach. By applying appropriate sparsification techniques, sparse PEEC matrices can be obtained, adequate for iterative solvers. By using multi-level approaches, linear complexity w.r.t. time and memory consumptions can be achieved in the best case. Due to the fact that properties of PEEC matrices can differ drastically, we developed the automatic solver switching strategy α-SAMG. Its efficiency for PEEC matrices is demonstrated for seven practically relevant benchmark cases by comparison against standard solvers. In particular, it is shown that α-SAMG provides a robust and fast solution strategy.
elib2cris::1512001600,clees2007

An Efficient and Cost Effective SAW Device Measurement Method Based on an S-Parameter Estimation Technique - Johnson, John; Weigel, Robert (International Microwave Symposium Digest, 1995)
Efficient and cost effective testing is an important part of the production process of SAW components. One aspect of testing is the measurement of the device transfer characteristic. In many cases expensive test fixtures containing matching networks are required. In order to reduce production costs and facilitate the measurement of transfer functions without matching networks, a different approach has been taken. Through use of estimation methods one can reduce the amount of information required to calculate a matched transfer function. Therefore, we developed a method by which a simulated match could be performed, but required only knowledge of the unmatched and uncalibrated S21-parameter. The feasibility of our technique is demonstrated with a low loss IF SPUDT filter for mobile telephone applications
elib2cris::1512001600,johnson1995

An Efficient Neural Network Based Modeling Method for Automotive EMC Simulation - Frank, Florian; Weigel, Robert (Frequenz, 2011)
This paper presents a newly developed methodology for VHDL-AMS model integration into SPICE-based EMC simulations. To this end the VHDL-AMS model, which is available in a compiled version only, is characterized under typical loading conditions, and afterwards a neural network based technique is applied to convert characteristic voltage and current data into an equivalent circuit in SPICE syntax. After the explanation of the whole method and the presentation of a newly developed switched state space dynamic neural network model, the entire analysis process is demonstrated using a typical application from automotive industry.
elib2cris::1512001600,frank2011

An Efficient Two-Fold Marginalized Bayesian Filter for Multipath Estimation in Satellite Navigation Receivers - Krach, Bernhard; Robertson, Patrick; Weigel, Robert (EURASIP Journal on Advances in Signal Processing, 2010)
Multipath is today still one of the most critical problems in satellite navigation, in particular in urban environments, where the received navigation signals can be affected by blockage, shadowing, and multipath reception. Latest multipath mitigation algorithms are based on the concept of sequential Bayesian estimation and improve the receiver performance by exploiting the temporal constraints of the channel dynamics. In this paper, we specifically address the problem of estimating and adjusting the number of multipath replicas that is considered by the receiver algorithm. An efficient implementation via a two-fold marginalized Bayesian filter is presented, in which a particle filter, grid-based filters, and Kalman filters are suitably combined in order to mitigate the multipath channel by efficiently estimating its time-variant parameters in a track-before-detect fashion. Results based on an experimentally derived set of channel data corresponding to a typical urban propagation environment are used to confirm the benefit of our novel approach.
elib2cris::1512001600,krach2010

An Embedded System Architecture for UPnP Compatible Wireless Control Networks - Bichler, Daniel; Borbely, S.; Fachberger, M.; Gsottberger, Y.; Huemer, Mario; Knauseder, Roman; Linde, Holger; Naroska, Edwin; Pfaff, Markus; Schramm, Peter; Shi, Xiaoyao; Stromberg, Guido; et al. (International Symposium on Signals, Systems, and Electronics, 2004)
elib2cris::1512001600,bichler2004

An Ensemble LSTM Architecture for Clinical Sepsis Detection - Schellenberger, Sven; Shi, Kilin; Wiedemann, Jan Philipp; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (International Conference in Computing in Cardiology 2019, 2019)

An Error Compensation Algorithm for Indirect Resonant Planar Relative Permittivity Sensor Principles up to 100 GHz - Lau, Isabella; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes, 2019)
This paper presents an error compensation algorithm for indirect resonant planar relative permittivity sensor principles up to 100 GHz. Besides the measurement of the material under test (MUT), the algorithm requires additional measurements of at least two reference materials. The proposed algorithm is tested for the three most relevant modeling errors occurring while measuring with an indirect planar measurement principle. These include erroneous assumptions regarding the geometrical dimensions, the effective roughness and the air gap between the sensor and the MUT. The proposed algorithm results in an average improvement of the error of the extracted relativen permittivity values of 90.46 %.<br
Keywords: error compensation; materials nondestructive testing; microwave measurements; permittivity

A New Addressing Method for LUT Based Digital Predistortion Linearizers - Ceylan, Nazim; Müller, Jan-Erik; Weigel, Robert (International Symposium on Signals, Systems, and Electronics (ISSSE), 2004)
elib2cris::1512001600,ceylan2004

A New Approach For A Dual-Polarized Low Cost Patch Antenna With Low Cross- Polarization, High Bandwidth And High Isolation - Stöckle, Andreas; Lutz, Steffen; Talai, Armin; Fischer, Georg (IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, 2014)
In this paper a new approach for a dual- polarized broadband patch antenna is presented. A novel feeding approach enables a high -10dB band- width up to 21 % as well as an isolation more than -29 dB. The realized antenna gain is > 6 dBi in the frequency range of 1320 MHz to 1680 MHz. Addi- tional, due to the re ector shaping, a low back ra- diation is achieved. Since standard components and FR4 material are used, the antenna concept enables an e ective low cost antenna production.
elib2cris::1512001600,stoeckle2014

A New Approach for Analog Filter Design with Mask Constraints Utilizing Linear Programming - Koca, Özhan; Hubert, K.; Weigel, Robert (International Symposium on Signals, Systems and Electronics, 2007)
This paper presents a new and efficient method to approximate all-pole analog filters by considering magnitude constraints in the frequency domain. A specified tolerance scheme is transformed into a linear programming problem, which can be efficiently solved by available optimization software. Thereby, the use of linear programming enables the designer to compute filter coefficients by optimizing design variables as e.g. the gain ripple in pass band. Furthermore, this approach makes possible to easily find alternative low order filters in a larger solution space, which will lead to a cost reduction in the design flow. Additionally, a modified form of the proposed method can be employed to consider coefficient uncertainties caused by component variations. Examples are provided to validate the benefits of the resulting design method.
elib2cris::1512001600,koca2007

A New Approach on MEMS Sensor Batch Testing Using an Analogue Parallel Test Methodology for Massive Reduction of Test Time - Oesterle, Florian; Weigel, Robert; Kölpin, Alexander (IEEE Sensors, 2013)
With a tremendous shipment increase of MEMS microphones during the last few years, enhanced testing methods have become a key issue for industrial batch manufacturing, focusing on the mechanical sensitivity of the sound transducing diaphragm. Instead of semi-parallel techniques, in which test channels and measurement equipment are duplicated (with a multiplication of invest) for the purpose of further reduction of test time, this paper shows a novel approach for a massive parallel test of MEMS sensors. With several DUTs connected in parallel, the resulting measurements hence reveal several overlain device characteristics, each accounting for the sensitivity of one single DUT. For the specific correlation of those characteristics to each DUT, a reconstruction method known from tomography imaging techniques is adapted. The measurement results on wafer level shown in this paper exhibit the basic suitability of a single test of several DUTs in parallel and prove the concept of this novel method
elib2cris::1512001600,oesterle2013b
Keywords: MEMS; Parallel Testing; Mechanical Sensitivity; Pull-In; Microphone; Tomographic Reconstruction

A new Approach on Mobile Phone Localization for Search and Rescue Applications - Zorn, Stefan; Rose, Richard; Götz, Alexander; Weigel, Robert (International conference on indoor positioning and indoor navigation (IPIN), 2010)
Recent statistics show an increase in environmental disasters, a fact which is also perceivable to the public as reports of avalanches, earthquakes and landslides mount in media coverage. Search and Rescue with modern localization techniques consequently attracts attention from scientific and industrial sides. This paper introduces one part of the I-LOV project, endorsed by the Federal Ministry of Education and Research Germany. Here partners from relief organizations, universities and industry investigate enhancements to disaster handling and victim rescue. One possible option is to take advantage of the fact, that a lot of people own a mobile phone today. Future developments in the area of mobile phone detection by field intensity measurements will be addressed in this paper.
elib2cris::1512001600,zorn2010
Keywords: Clocks; GSM; Phase locked loops; Protocols; Radio frequency; Universal Serial Bus

A new BIST scheme for low-power and high-resolution DAC testing - Li, Hongzhi; Eckmüller, Josef; Sattler, Sebastian; Eichfeld, Herbert; Weigel, Robert (Advances in Radio Science : Kleinheubacher Berichte, 2003)
A BIST scheme for testing on chip DAC is presented in this paper. We discuss the generation of on chip testing stimuli and the measurement of digital signals with a narrow-band digital filter. We validate the scheme with software simulation and point out the possibility of ADC BIST with verified DACicus-journals.
elib2cris::1512001600,li2003

A New BIST Scheme for the DAC SNDR Testing of an Audio Chip. - Li, Hongzhi; Eckmüller, Josef; Russo, Michaela; Sattler, Sebastian; Eichfeld, Herbert; Weigel, Robert (9th International Mixed-Signal Testing Workshop, 2003)
elib2cris::1512001600,li2003b
Keywords: BIST; DAC; SNDR; audio

A New Compact Model for the Avalanche Effect in InAlAs/InGaAs HBTs - Weiß, Oliver; Baureis, Paul; Kellmann, Nikolai; Weber, Norbert; Weigel, Robert (IEEE Electron Device Letters, 2006)
This letter presents a new compact model for the avalanche effect in InAlAs/InGaAs heterojunction bipolar transistors. Unlike previous models, it is based on the formulation of the avalanche multiplication by Lee (Phys. Rev., vol. 134, p. A761, 1964), which allows the model to be valid for even larger current densities than before. The description of the ionization coefficient takes into account the anomaly of the ionization coefficient of InGaAs at low electric fields. The new model is successfully verified by measurements in a conventional common-base setup.
elib2cris::1512001600,weiss2006
Keywords: III-V semiconductors; aluminium compounds; current density; gallium arsenide; heterojunction bipolar transistors; indium compounds; semiconductor device models; InAlAs-InGaAs; avalanche effect; avalanche multiplication; current density; electric fields; heterojunction bipolar transistor; impact ionization; ionization coefficient; Bipolar transistors; Current density; Electrons; Heterojunction bipolar transistors; Impact ionization; Indium compounds; Indium gallium arsenide; Indium phosphide; Optical fiber communication; Wireless communication; Avalanche effect; InGaAs; avalanche multiplication; heterojunction bipolar transistor (HBT); impact ionization; indium phosphide

A New Concept for Aligning Automotive Long-Range Radar Modules Based on Wireless Microwave Sensing - Weigel, Robert; Vinci, Gabor; Lämmle, Benjamin; Kölpin, Alexander (Sensor & Test, 2011)
elib2cris::1512001600,weigel2011d

A New Heat-Warning-System Based on a Wireless Body Area Network for Protecting Firefighters in Indoor Operations - Dietz, Marco; Striegel, Martin; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE Topical Conference on Wireless Sensors and Sensor Networks, 2018)
A new Heat-Warning-System is presented to protect firefighters in indoor operations. With the proposed Heat-Warning-System, a permanent monitoring of the body core temperature can be done, in order to protect the firefighter from a collapse. Furthermore, by placing several temperature sensors around the thorax on particular positions, the relative location of dangerous heat sources can be estimated. For the placement of the sensor nodes, an empirical channel model in combination with a cuboid body model was used, to estimate the individual transmission path losses by taking into account the influence of the human body. Finally, the Heat-Warning-System is tested and moreover the locating functionality of dangerous heat sources is shown.

A new high-temperature superconducting double-hybrid coupler with wide bandwidth - Bechteler, Thomas; Mayer, Bernd; Weigel, Robert (Microwave Symposium Digest, IEEE MTT-S International, 1997)
We report on the design and performance of new high-temperature superconducting couplers fabricated in microstrip technology. We present experimental results for a 3 dB- and a 0 dB-coupler (i.e. a crossover device) at 10 GHz. The planar coupler structures were patterned into YBaCuO thin films deposited on MgO substrates on both sides. As a design tool, we employed a commercial microwave simulation program. Verification was done using special test chips. We attained extremely low insertion loss values over bandwidths of 45 per cent (3 dB-coupler) and 30 per cent (0 dB-coupler), respectively.
elib2cris::1512001600,bechteler1997a
Keywords: Bandwith; Circuit simulation; circuit testing; couplings; Couplings; High temperature superconductors; microstrip; Superconducting microwave devices; Superconducting transmission lines; Transmission line theory; Yttrium barium copper oxide

A new IP core integration concept for signal manipulation and timing adjustment using a configurable I/O architecture - Franchi, Norman; Weigel, Robert; Cai, Z.; Schmid, J.; Rauch, Hans (23. GI/GMM/ITG Workshop Testmethoden und Zuverlässigkeit von Schaltungen und Systemen, 2011)
Obsolescence of electronic components is a serious problem and challenge for electronics industry affecting nearly every electronic system. The problem of ensuring backward compatibility caused by replacing obsolete system parts must be solved by reproducing the specific functionality and system behaviour of the replaced component. This paper addresses an online configurable I/O architecture that allows user-defined I/O signal manipulations via JTAG interface for FPGA logic designs with integrated IP soft core as replacement for an obsolete chip. In addition to this the flexible configuration affords the opportunity to realize an automated test strategy. Thus embedded-core based system chips can be analyzed, tested and re-/configured automatically.
elib2cris::1512001600,franchi2011a
Keywords: Obsolescence; IP soft core; FPGA; VHDL; JTAG; DFT; pipelining; delay test; signal manipulation; online configuration

A New Nonlinear Multi-Filter Detection Concept for the High Density Magnetic Recording Channel - Obernosterer, Frank; Kratzert, Andreas; Oehme, Friedrich (IEEE Transactions on Magnetics, 1998)
In this work, a new approach to detection in high density magnetic recording is presented. The basic detector structure is a bank of parallel sub-detectors which are specialized in different channel states. The individual adaptation of the sub-detectors to the channel properties is done by a learning algorithm so that no explicit channel model is required. On both simulated and experimental data it is shown that the proposed detection scheme has excellent performance in the presence of strong nonlinear distortion and signal dependent noise. At user densities of 3.5 and 4.0 using RLL(1,7) encoding the new scheme outperforms multi-level decision feedback equalization (MDFE) detection by a factor of up to 500 in error rate. The structure is well suited for hardware implementation. © 1998 IEEE.
UnivIS-Import:2015-03-05:Pub.1998.tech.IE.LETE.anewno
Keywords: Detection; Magnetic recording; Neural network; Nonlinear filtering

A new synthesis method for broadband dispersive 180° reflecting arrays in SAW devices - Müller, Günter; Sindic, G.; Seifert, Franz; Weigel, Robert (IEEE Ultrasonics Symposium, 1993)
An increasing number of SAW filter configurations contains 180° reflecting arrays. For broadband applications chirped reflectors are needed. The design of unweighted dispersive arrays yields unbearable deviations from a flat stopband. To tackle this problem we have worked out a sophisticated synthesis method using finger width- and phase-weighting which are the best suitable techniques for broadband reflectors. Using the stationary phase principle and the infinite array approximation we can compute the reflection factor of each finger in a dispersive array with slowly varying pitch. We present an iterative design procedure based on the relation between the frequency response of a dispersive array and the local reflectivity. The feasibility of our synthesis procedure is confirmed by experimental results
elib2cris::1512001600,mueller1993

A new System for Mobile Phone Localization for Search and Rescue Applications - Weigel, Robert; Kölpin, Alexander; Rose, Richard; Zorn, Stefan; Götz, Alexander (Future Security, 2011)
elib2cris::1512001600,weigel2011g

A new technique to improve AoA using dual polarization - Rose, Richard; Zorn, Stefan; Götz, Alexander; Fischer, Georg; Weigel, Robert (European Microwave Conference, 2011)
This paper presents a technique for reducing the AoA measurement error caused by the influence of multipath propagation. This technique can be implemented using two approaches, where either the amplitude or the power of the received signals in the polarization domain can be implicated. After the polarization angle of the LOS signal is derived, the dual polarized antenna configuration has to be computationally rotated by this angle to reduce the influence of multipath components. The simulation results show, that the proposed technique leads to a significant reduction of AoA estimation error originated from a multipath component.
elib2cris::1512001600,rose2011a

An Exploration of Hierarchical Design Implementation Flows - Fasthuber, R.; Papanikolaou, M.; Huemer, Mario (Austrochip 2007, 2007)
elib2cris::1512001600,fasthuber2007

An Extension of Power Amplifier Behavioral Models for Optimizing Battery Current at System Level - Glock, Stefan; Sogl, Bernhard; Vizaretta, P.; Ußmüller, Thomas; Müller, Jan-Erik; Fischer, Georg; Weigel, Robert (IEEE Radio and Wireless Week, 2013)
One of the most significant figures of merit concerning a power amplifier is its effficiency. However, behavioral models of power amplifiers are mainly focused on functional aspects but not on current consumption. Therefore, simulations with respect to the efficiency of a power amplifier cannot be accomplished at system level. To close the gap of simulation capabilities, this article proposes a time efficient and accurate extension of behavioral models to predict current consumption. The current consumption model accounts for different bias conditions. For a commercial handset power amplifier, an average error of 1.9% between the fast highlevel model and measurement results is obtained.
elib2cris::1512001600,glock2013

An FPGA-Based Fully Synchronized Design of a Bilateral Filter for Real-Time Image Denoising - Gabiger-Rose, Anna; Kube, Matthias; Weigel, Robert; Rose, Richard (IEEE Transactions on Industrial Electronics, 2014)
In this paper, a detailed description of a synchronous field-programmable gate array implementation of a bilateral filter for image processing is given. The bilateral filter is chosen for one unique reason: It reduces noise while preserving details. The design is described on register-transfer level. The distinctive feature of our design concept consists of changing the clock domain in a manner that kernel-based processing is possible, which means the processing of the entire filter window at one pixel clock cycle. This feature of the kernel-based design is supported by the arrangement of the input data into groups so that the internal clock of the design is a multiple of the pixel clock given by a targeted system. Additionally, by the exploitation of the separability and the symmetry of one filter component, the complexity of the design is widely reduced. Combining these features, the bilateral filter is implemented as a highly parallelized pipeline structure with very economical and effective utilization of dedicated resources. Due to the modularity of the filter design, kernels of different sizes can be implemented with low effort using our design and given instructions for scaling. As the original form of the bilateral filter with no approximations or modifications is implemented, the resulting image quality depends on the chosen filter parameters only. Due to the quantization of the filter coefficients, only negligible quality loss is introduced.
elib2cris::1512001600,gabiger-rose2014
Keywords: Bilateral filter; field-programmable gate array (FPGA)

An Improved Path Profiling Algorithm for Mobile Positioning in UMTS - Mosshammer, Ralf; Drewes, Christian; Huemer, Mario (11th European Wireless Conference (EW), 2005, 2005)
Location Based Services (LBS) and the FCC (Federal Communications Commission) mandate for mobile 911 calls are driving forces in the development of positioning algorithms in third generation mobile handsets. In this work, we present an improvement upon the common path profiling method. The proposed algorithm averages multiple slots and subjects the distinct delay profiles to a number of exclusion criteria which sort out highly noise-corrupted measurements. Simulations prove that the method obtains high accuracy gains at very low implementational and computational complexity.
elib2cris::1512001600,mosshammer2005
Keywords: Aging; Complexity theory; Equations

An Improved Switched Injection-Locked Oscillator for Ranging and Communication Systems - Eßwein, Alexander; Carlowitz, Christian; Vossiek, Martin; Weigel, Robert; Ußmüller, Thomas (43rd European Microwave Conference, 2013)
This paper describes an improved integrated switched injection-locked oscillator (SILO) circuit for use in pulsed angular modulated ultra wideband communication and radar systems, implemented in a 0.25 μm SiGe:C BiCMOS technology. The circuit consists of two active baluns for single-ended to differential and differential to single-ended conversion, a Schmitt-trigger with two pulse generators based on current-starved voltage controlled delay lines and inverter chains and a simple Q-degenerated cross-coupled oscillator for signal generation. It has an externally controllable pulse repetition rate and duration. The previous works of the authors [1] was severely improved in the area of required locking power and pulse duration control. Required injection power has been reduced to -65 dBm. During operation it consumes combined 40mA from 3.3V analog and 2.5V digital supply voltage, while generating a 370mV pp signal. The generated signal has a 10 dB-bandwidth ofs over 2.3 GHz at 6.8 GHz center frequency. Measurement results are shown. © 2013 European Microwave Association.
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.animpr
Keywords: Injection-Locking; Integrated Circuit; Pulse Generation; Pulsed Frequency Modulated Radar; Radar; VCO

An inductor-less LTE receiver using an 8-path filter for TX leakage suppression - Elmaghraby, Ahmed; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (IEEE Silicon Monolithic Integrated Circuits in RF Systems, 2014)
elib2cris::1512001600,elmaghraby2014

An input amplitude modulated harmonic outphasing PA - Abou-Chahine, Zeid; Felgentreff, Tilman; Fischer, Georg; Weigel, Robert (13th Mediterranean Microwave Symposium (MMS), 2013)
elib2cris::1512001600,abou-chahine2013

An integrated 125 GHz sensor with read-out circuit for permittivity measurement of liquids - Lämmle, Benjamin; Schmalz, Klaus; Scheytt, Christoph; Weigel, Robert; Kissinger, Dietmar (IEEE MTT-S International Microwave Symposium, 2012)
elib2cris::1512001600,laemmle2012a

An Integrated 132–147GHz Power Source with +27dBm EIRP - Visweswaran, Akshay; Haag, Alexander; de Martino, Carmine; Schneider, Karina; Maiwald, Tim; Vignon, Bastien; Aufinger, Klaus; Spirito, Marco; Zwick, Thomas; Wambacq, Piet (Radio Frequency Integrated Circuits (RFIC), IEEE Symposium, 2020)

An Integrated 28 GHz Front-End Module for 5G Applications in 45 nm PD-SOI - Ciocoveanu, Radu; Lammert, Vincent; Weigel, Robert; Issakov, Vadim (2019 IEEE MTT-S International Microwave Conference on Hardware and Systems for 5G and Beyond, IMC-5G 2019, 2019)
This paper presents an integrated 28 GHz front-end module (FEM) for 5th Generation (5G) applications and fabricated in a 45 nm partially depleted silicon on insulator (PD-SOI) technology. In transmit (Tx) mode at 28 GHz, the measured saturated output power (Psat), maximum power-added efficiency (PAEmax), output-referred 1-dB compression point (OP1dB) are 17.2 dBm, 26 % and 16.7 dBm, respectively, with 86.4 mW dc power consumption from a 1.8 V supply. In receive (Rx) mode at 28 GHz, the measured gain, noise figure (NF), input-referred 1-dB compression point (IP1dB) are 9dB, 3.6dB and -10dBm, respectively, with 14.8mW dc power consumption from a 1 V supply. The chip core size is 0.62mm x 0.75mm.
CRIS-Team Scopus Importer:2021-04-20

An Integrated 77-GHz Six-Port Receiver Frontend for Angle-of-Arrival Detection - Lämmle, Benjamin; Vinci, Gabor; Maurer, Linus; Kölpin, Alexander; Weigel, Robert (Bipolar/BiCMOS Circuits and Technology Meeting (BCTM) 2011, 2011)
In this publication 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, auto-motive radar calibration, or high precision industrial radar. The measurement principle is based on superposition of two incident signals and power detection. The circuit has two input amplifiers, a broadband passive six-port network, and four power detectors. The integrated circuit has a power consumption of 95mW with 5V supply voltage. It is fabricated in a 200-GHz fT SiGe bipolar technology and occupies only 1028 × 1128 μm2. Functionality is demonstrated by applying two different frequencies at the input ports. A simple calibration method is proposed and all calibration parameters are calculated.
elib2cris::1512001600,laemmle2011b
Keywords: Antenna measurements; Calibration; Detectors; Frequency measurement; Phase measurement; Radar; Six-Port

An Integrated Bistatic 4TX/4RX Six-Port MIMO-Transceiver at 60GHz in a 130-nm SiGe BiCMOS Technology for Radar Applications - Völkel, Matthias; Pechmann, Stefan; Ng, Herman Jalli; Kissinger, Dietmar; Weigel, Robert; Hagelauer, Amelie (PROCEEDINGS OF THE 2020 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS), 2020)
CRIS-Team WoS Importer:2021-04-30

An Integrated Circuit for Decoupling and Tuning of Inverted-F Antennas in Cellular User Equipment - Özdamar, Oguzhan; Weigel, Robert; Solomko, Valentyn; Hagelauer, Amelie (2021 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS), 2021)
CRIS-Team WoS Importer:2021-11-12

An Integrated Periodic Structure in Silicon Technology to Improve Power Amplifier Parameters - Kitlinski, Krzysztof; Kitlinski, Marek; Weigel, Robert (16th International Conference on Microwaves, Radar and Wireless Communications, 2006)
A new integrated periodic structure in silicon technology has been introduced to a power amplifier (PA) interstage matching network. Through the broadband matching characteristics and filtering abilities the PA's parameters have been significantly improved.
elib2cris::1512001600,kitlinski2006

An Integrated SiGe Bipolar VCO with Linearized Tuning Behavior and Ultra-Wide Tuning Range for UWB FMCW Local Positioning Systems - Maser, Matthias; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (2012 International Semiconductor Conference Dresden - Grenoble, 2012)
This paper describes an integrated voltage controlled oscillator (VCO) with linearized tuning behavior for ultra-wideband local positioning radar applications. The VCO is LC-resonator based and uses a tunable negative inductance cell (NI-cell) in conjunction with a differential junction varactor to achieve an ultra-wide, continuous frequency tuning range (FTR). A tuning linearization circuit is used to couple both tuning mechanisms to attain a more constant tuning sensitivity (K_VCO). The presented VCO offers a measured FTR from f_min = 3.365 GHz to f_max = 7.677 GHz. The tuning curve is linearized in a frequency range of 2.1 GHz with a measured K_VCO-deviation of only +/-10% around K_VCO = 775 MHz/V, which corresponds to a relative FTR of 34%.
elib2cris::1512001600,maser2012
Keywords: FMCW-radar; negative inductance; SiGe Bipolar; tuning linearization; ultra-wide continuous tuning range; voltage controlled oscillator

An Integrated Switched Injection-Locked Oscillator for Pulsed Angle Modulated Ultra Wideband Communication and Radar Systems - Eßwein, Alexander; Carlowitz, Christian; Fischer, Georg; Vossiek, Martin; Weigel, Robert; Ußmüller, Thomas (IEEE International Conference on Ultra-Wideband, ICUWB 2012, 2012)
This paper describes an integrated switched injection-locked oscillator (SILO) circuit for use in pulsed angular modulated ultra wideband communication and radar systems. The circuit consists of two active baluns for single-ended to differential and differential to single-ended conversion, a Schmitt-trigger with modified current mirror load for current peak generation and a simple cross-coupled oscillator for signal generation. It has an externally controllable pulse repetition rate and a pulse duration of approx. 1ns. During operation it consumes 33mA at 3.3V supply voltage, while generating a 370 mVpp signal. The generated signal has a 10dB-bandwidth of over 2GHz at 7.5 GHz center frequency. Measurement results with an external baseband generator are shown. © 2012 IEEE.
UnivIS-Import:2015-04-16:Pub.2012.tech.IE.LEH.aninte
Keywords: Injection-Locking; Integrated Circuit; Pulse Generation; Pulsed Frequency Modulated Radar; Radar; VCO

An Interference Cancellation Technique for the Use in Multiband Software Radio Frontend Design - Schacherbauer, Werner; Ostertag, Thomas; Ruppel, Clemens; Springer, Andreas; Weigel, Robert (European Microwave Conference, 2000)
elib2cris::1512001600,schacherbauer2000

An Interstage Filter-Free Mobile Radio Receiver with Integrated TX Leakage Filtering - Vazny, Rastislav; Schelmbauer, Werner; Pretl, Harald; Herzinger, Stefan; Weigel, Robert (Radio Frequency Integrated Circuits (RFIC) Symposium, 2010, 2010)
A multi-standard, multi-band fully-integrated interstage filter-free receiver with integrated auto-centered TX leakage filtering is fabricated in a 65 nm CMOS technology. The measured TX selectivity in UMTS band II is 9.1 dB, the receiver gain at 1.96 GHz is 54.1 dB, and NF is 3.68 dB. The 0.5 dB reference sensitivity degradation caused by TX leakage is reached at a TX power level of -20 dBm/3.84MHz.
elib2cris::1512001600,vazny2010
Keywords: 3G mobile communication; CMOS technology; Integrated circuit noise; Filtering; Filters; Integrated circuit noise; Linearity; Noise figure; Noise level; Receivers

An Investigation of the Proximity Effect of Millimeter-Wave MMICs in Flip-Chip Configuration - Nagy, Oliver; Heide, Patric; Springer, Andreas; Weigel, Robert (IEEE : European Microwave Conference, 2001)
A comparison between flip-chip mounting of monolithic microwave integrated circuits (MMICs) in microstrip transmission line technology and coplanar transmission line technology is presented. The influence of substrate proximity effects on the electrical behavior of the MMICs is examined and illustrated in normalized frequency independent graphs. Based on the results of this work, the performance of microstrip-MMICs used in flip-chip configuration can be estimated as a function of the chosen assembly geometry.
elib2cris::1512001600,nagy2001b
Keywords: Proximity Effect; MMIC; Flip-Chip

An ISO 26262 compliant built-in self-test for 77 GHz automotive radar sensors - Schnabel, Raik; Steinbuch, Dirk; Weigel, Robert (European Radar Conference, 2013)
elib2cris::1512001600,schnabel2013a

An OFDM MIMO Transmitter for Wireless Gigabit with Advanced Multimedia (WIGWAM) - Simon, Martin; Winter, Sebastian; Klepser, Bernd-Ulrich; Weigel, Robert (European Conference on Wireless Technologies, 2007, 2007)
A fully integrated high linearity low power and low cost transmitter in 120 nm CMOS technology with 2 RF-paths and integrated balun for broadband OFDM MIMO application is presented. The transmitter is used for the Wireless Gigabit with Advanced Multimedia (WIGWAM) research project. A maximum datarate of 970 Mbit/s can be achieved by transmitting a 256QAM OFDM MIMO signal with 80 MHz bandwidth and 7/8 code rate. The Error Vector Magnitude is only -28 dB due to low phase noise and high linearity. The RF coupling between the 2 MIMO TX paths is 32 dB. The carrier and sideband of the vector modulator are calibrated with an integrated down-conversion mixer.
elib2cris::1512001600,simon2007a

A nonlinear FEM model to calculate third harmonics and intermodulation in TC-SAW devices - Chauhan, Vikrant; Mayer, Markus; Ruile, Werner; Wagner, Karl; Mayer, Andreas; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE International Ultrasonics Symposium, 2018)

An online telemetering system for mobile health parameter monitoring and medical assistance - Agethen, Roman; Lurz, Fabian; Schwarzmeier, Andre; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (Internation Conference on Sensing Technology, 2011)
elib2cris::1512001600,agethen2011b

An Open-Source Speech Codec at 450 bit/s with Pseudo-Wideband Mode - Erhardt, Stefan; Kurin, Thomas; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (European Microwave Conference 2019, 2019)

An OTA-based 18-Bit SAR ADC Driver with Slew Rate Boost and Chopper Stabilization - Mai, Timo; Weigel, Robert (Workshop Analogschaltungen, 2020)

An Outphasing MIMO Architecture Prototype - Gäde, Bernhard; Erhardt, Stefan; Fischer, Georg; Müller, Ralf (European Microwave Week 2020, 2021)
In this manuscript we present the first prototype of an Outphasing MIMO Architecture (OMA). The concept of this architecture is to replace many linear power amplifiers by a single and simple power oscillator and phase modulate the carrier directly in the analogue domain. The prototype is designed to support Phase-Shift Keying on the Hypersphere (PSKH) modulation, which is a recent modulation scheme optimised for load-modulated Multiple Input Multiple Output (MIMO) transmitters. It is shown by analysis of the steady state and dynamic behaviour of the prototype that OMA is suitable to implement direct carrier modulated PSKH at rates up to 50 MSym/s using stock components only.<br
Keywords: direct carrier modulation; OMA; MIMO; PSKH

A novel 2-12GHz 14dBm High Efficiency Power Distributed Amplifier for Ultra-Wideband- Applications Using a Low-Cost SiGe BiCMOS Technology - Sewiolo, Benjamin; Weigel, Robert (IEEE MTT-S International Microwave Symposium Digest, 2008, 2008)
In this paper the analysis, design and measurement results of a novel 2-12 GHz power distributed amplifier for ultra-wideband radar and sensing applications is presented. The amplifier is fabricated in a low-cost 0.25 μm SiGe BiCMOS technology with a transit frequency of 25GHz. 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 ±0.5 dB with total power consumption of 250mW. 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 1.16mm2. Good agreement between simulation and measurement were achieved.
elib2cris::1512001600,sewiolo2008a

A Novel Approach for Reliable Communications within Inductive Power Transfer Systems - Sanftl, Benedikt; Pflaum, Felix; Trautmann, Martin; Weigel, Robert; Kölpin, Alexander (Wireless Power Transfer Conference (WPTC), 2016)
This paper presents a novel approach for simultaneous inductive power transfer (IPT) and communication in one system. The communication part is using the coupled pair of coils of the IPT system as transmitting medium. The proposed architecture is usable in new and existing IPT systems with operating frequencies above 100 kHz. The challenge is to enable robust and reliable communication in the noisy environment of the power transfer. High reliability is necessary as it shall transmit sensor data error free. For example, this data link can be used for closed-loop operation of the IPT system. Through its fully digital implementation it can be quickly adapted for various other applications. It will be shown that a reliable communication system with joint power transfer and continuous data transmission over the same pair of coupling coils can be realised. Even during high power transfers it features a robust communication channel with outstanding signal to noise ratio and advantageous error vector magnitude. For proof of concept the key performance values of the proposed communication architecture are measured in a 20 W IPT system.
elib2cris::1512001600,sanftl2016a

A novel approach to non-invasive blood glucose measurement based on RF transmission - Hofmann, Maximilian; Fersch, Thomas; Weigel, Robert; Fischer, Georg; Kissinger, Dietmar (IEEE International Workshop on Medical Measurements and Applications, 2011)
A new approach to non-invasive blood parameter measuring is presented, which consists of two matched antennas for transmission based two port measurements. The current situation of patients suffering from diabetes mellitus and their need for novel blood sugar level measuring techniques is presented. Dielectric properties of body tissues are reviewed and their influence on transmission properties are estimated for plane wave propagation. A covered patch antenna and substrate integrated waveguide slot antenna has been designed, measured and compromised for glucose-concentration measurements. Further, several test locations are discussed with respect to an accurate measurement. The introduced antennas were optimized and fabricated with respect to the dielectric and mounting properties of human tissues.
elib2cris::1512001600,hofmann2011b

A Novel BIST Technique for SNR DAC Testing. - Li, Hongzhi; Eckmüller, Josef; Sattler, Sebastian; Eichfeld, Herbert; Weigel, Robert (Workshop Entwurf Integrierter Schaltungen und Systeme, 2003)
elib2cris::1512001600,li2003a
Keywords: BIST; SNR; DAC; Testing

A Novel Cascode Power Matching Approach for High Efficiency Tapered Traveling Wave Power Amplifiers in SiGe MiCMOS - Sewiolo, Benjamin; Waldmann, Benjamin; Fischer, Georg; Weigel, Robert (International Conference on Ultra-Wideband, 2009)
elib2cris::1512001600,sewiolo2009g

A Novel Closed Loop Current Sensor Based on a Circular Array of Magnetic Field Sensors - Weiss, Roland; Itzke, Alexander; Reitenspiess, Julian; Hoffmann, Ingolf; Weigel, Robert (IEEE Sensors Journal, 2019)
During the last years, coreless current sensors based on circular arrays of magnetic field sensors have been investigated. These sensors were limited in bandwidth and accuracy by the magnetic field sensors used to realize the circular arrays. Thus, this paper applied the well-known "closed loop" principle to circular array-based current sensors to overcome these limitations. This paper gives a comparison between circular arrays built from Hall and Fluxgate magnetic field sensors in both the closed loop and open loop operation. If closed loop configuration Fluxgate sensors are used, instead of Hall sensors, the measurement error can be reduced by a factor of two due to their intrinsic characteristics. Moreover, it is shown that the closed loop operation of the circular arrays results in a significant reduction of the temperature drift of the sensitivity for Fluxgate and Hall sensor-based circular arrays. If Hall sensors are used for the circular array, the reduction of the temperature drift of the sensitivity achieved by closed loop operation is about a factor of 10. If Fluxgate sensors are used, a significant reduction of the nonlinearities like hysteresis and a substantial reduction of the temperature drift of the sensitivity was observed.
CRIS-Team WoS Importer:2019-03-20
Keywords: Sensor arrays; core less current sensor; Hall-effect sensors; Fluxgate sensors; current sensing; contactless current measurement; closed loop; open loop; Amperes law

A Novel Crest Factor Reduction Technique using Memoryless Polynomials - Farabegoli, Alessio; Sogl, Bernhard; Müller, Jan-Erik; Weigel, Robert (44th European Microwave Conference (EuMC), 2014)
elib2cris::1512001600,farabegoli2014

A Novel DC Offset Compensation Approach for TDMA Systems Using a Direct Conversion Receiver Architecture - Deutsch, Gerhard; Krüger, Martin; Springer, Andreas; Weigel, Robert (Informationstagung Mikroelektronik, 2003)
elib2cris::1512001600,deutsch2003

A novel, fast, and precise Method to perform Time Alignment Estimation and Compensation - Farabegoli, Alessio; Sogl, Bernhard; Müller, Jan-Erik; Weigel, Robert (IEEE Topical Conference on Power Amplifiers for Wireless and Radio Applications (PAWR), 2013)
In this paper, a novel procedure to estimate and compensate the delay between power amplifier's input and output waveforms is described. The proposed method has been developed in order to achieve fast computation and simple implementation that are required in state of the art mobile applications. In addition, the modular approach adopted offers high flexibility and enables further future improvements. Comparison with a traditional method like cross-correlation shows up to four times faster estimation time with the same precision. Resolution is furthermore improved estimating the fractional delay mismatch to increase the precision of the results with reduced sampling rate of the signals.
elib2cris::1512001600,farabegoli2013
Keywords: power amplifiers; cross-correlation; fractional delay mismatch estimation; mobile application; modular approach; power amplifier; reduced sampling rate; time alignment compensation

A Novel High Efficiency Power Amplifier Concept for GSM Handsets - Koller, Rainer; Stelzer, Andreas; Abt, Karl-Heinz; Weigel, Robert (International Workshop on Commercial Radio Sensing and Communication Techniques, 2001)
The demand for ever increasing talking times and reduced weight of modern GSM handsets can only be achieved by a significant reduction of the power consumption of the cellular handset, mostly the power the power amplifier (PA). The constant evelope modulation scheme of the GSM system allows the desing of high efficiency power amplifier, such as switching amplifiers. Among them. them, the Class-E amplifier concept is best suited, because it allows about 80% efficiency, while maintaining an excellent output spectrum and reasonable gain. Another advantage is the possibility to an a-priori design an characterization of the amplifier stage by simulation this fact is demonstrated in this paper, by comparing simulation and measurement results of a 45-MHz Class-E amplifier as a 1:20 frequency scaled model of a 900-MHz GSM power amplifier. The excellent match between theory and measurement allows a good prediction of the final Class-E amplifier characteristics by simulation.
elib2cris::1512001600,koller2001

A Novel High Efficiency Power Amplifier Concept for GSM Handsets - Koller, Rainer; Stelzer, Andreas; Abt, Karl-Heinz; Weigel, Robert (IEEE European Microwave Conference, 2001)
The demand for ever increasing talking times and reduced weight of modern GSM handsets can only be achieved by a significant reduction of the power consumption of the cellular handset, mostly the power the power amplifier (PA). The constant evelope modulation scheme of the GSM system allows the desing of high efficiency power amplifier, such as switching amplifiers. Among them. them, the Class-E amplifier concept is best suited, because it allows about 80% efficiency, while maintaining an excellent output spectrum and reasonable gain. Another advantage is the possibility to an a-priori design an characterization of the amplifier stage by simulation this fact is demonstrated in this paper, by comparing simulation and measurement results of a 45-MHz Class-E amplifier as a 1:20 frequency scaled model of a 900-MHz GSM power amplifier. The excellent match between theory and measurement allows a good prediction of the final Class-E amplifier characteristics by simulation.
elib2cris::1512001600,koller2001a
Keywords: GSM Handsets; Power Amplifier; High Efficiency

A Novel Hybrid Analog-Digital Transmitter for Multi-antenna Base Stations - Sedaghat, Mohammad Ali; Gäde, Bernhard; Müller, Ralf; Fischer, Georg (2017)
A new hybrid Analog-Digital (hybrid A-D) precoder is proposed for multi-antenna base stations in massive Multiple-Input Multiple-Output (MIMO) which allows a trade-off between the number of required RF-chains and the update rate of the analog part. It is shown that the number of RF-chains can be reduced even below the number of eigenmodes of the channel, thereby closing the gap between the standard hybrid A-D and the single-RF MIMO. This is achieved by dividing the input data streams into blocks and jointly optimizing the digital and the analog precoder parts for each block. The analog part of the precoder needs to be updated once per block and remains static over each block interval. Out of band radiation due to switching is resolved by inserting a short guard interval between blocks. It is shown the number of RF-chains can be any arbitrary positive integer to obtain zero distortion at the user terminals if the update rate is high enough. The proposed precoder offers a significant performance gain at the expenses of data dependent precoding and higher update rates of the analog part.

A Novel Hybrid Polar-I/Q Modulation Method relaxing RF Phase Modulator Design Requirements - Buckel, T.; Preyler, P.; Hager, E.; Mayer, T.; Tertinek, S.; Springer, Andreas; Weigel, Robert (2018 14TH CONFERENCE ON PHD RESEARCH IN MICROELECTRONICS AND ELECTRONICS (PRIME 2018), 2018)
CRIS-Team WoS Importer:2019-11-26

A novel IP2 calibration method for low-voltage downconversion mixers - Dufrene, Krzysztof; Weigel, Robert (IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, 2006, 2006)
This paper describes a novel IP2 calibration method for double balanced current-commutating downconversion mixers. The proposed technique reduces difference between duty cycle mismatches of two switching pairs in the mixer core, being suitable especially for low-voltage monolithic downconversion mixers employing common mode feedback block in the output stage. A tunable IQ mixer prototype, fabricated in a 0.13mum RF CMOS technology and operating under low voltage supply of 1.5 V, is presented. Experimental results confirm the feasibility of the IP2 tuning technique
elib2cris::1512001600,dufrene2006e
Keywords: 0.13 micron; 1.5 V; IP2 calibration; RF CMOS technology; common mode feedback block; duty cycle mismatches; low voltage downconversion mixers; tunable IQ mixer prototype; CMOS analogue integrated circuits; low-power electronics; mixers (circuits); radiofrequency integrated circuits

A Novel Method Based Upon Nonlinear Optimization for Analog Filter Design with Mask Constraints - Koca, Özhan; Karl, H.; Weigel, Robert (International Symposium on Signals, Systems, and Electronics (ISSSE2007), 2007)
This paper considers the optimization of analog filters which are not covered by classical approaches like Butterworth, Chebyshev, or Cauer approximations. Therefore, a novel and highly efficient method for analog filter design using nonlinear optimization is presented. This approach enables high flexibility and easy handling as compared to existing approximation techniques. By describing particular design specifications as constraints, a solution can be obtained by using suitable optimization software. Apart from the straightforward approximation of filter transfer functions, this approach is extensible to consider coefficient uncertainties of component variations. Furthermore, it can be used to synthesize filters comprised of only real poles. Examples are also provided to validate the benefits of the resulting design method.
elib2cris::1512001600,koca2007a

A Novel Power Amplifier Behavioral Model for Improving the Linearity-Efficiency Tradeoff - Glock, Stefan; Rascher, Jochen; Sogl, Bernhard; Ußmüller, Thomas; Müller, Jan-Erik; Fischer, Georg; Weigel, Robert (International Microwave and RF Conference (IMaRC), 2013)
This paper focuses on a novel power amplifier (PA) semi-physical behavioral model (BM) to study the linearityefficiency trade-off in modern wireless transmitter systems. While the behavioral models known in the literature mainly focus on the precise description of the PA nonlinearity in terms of amplitudemodulation- to-amplitude-modulation (AM-AM) and amplitudemodulation- to-phase-modulation (AM-PM) distortions, the model introduced here, also predicts the DC current flowing from the power supply to the PA. This allows to optimize the battery current while keeping the out-of-channel interference within specification limits. In a case study, the DC current and the amplitude distortions of a PA, designed for IEEE 802.11b/g/n applications are predicted with a normalized mean square error (NMSE) of -39.92 dB and -47.07 dB, respectively.
elib2cris::1512001600,glock2013c

A Novel Single-RF Outphasing MIMO Architecture - Gäde, Bernhard; Sedaghat, Mohammad Ali; Rachinger, Christoph; Fischer, Georg; Müller, Ralf (WSA 2017; 21th International ITG Workshop on Smart Antennas; Proceedings of, 2017)

A novel single RF-transmitter for massive MIMO - Sedaghat, Mohammad Ali; Müller, Ralf; Fischer, Georg (18th Int’l ITG Workshop on Smart Antennas, 2014)

A novel subgridding scheme for the distributed TLM modeling of thin layers - Isele, Bertram; Mangold, Tobias; Weigel, Robert; Russer, Peter (Progress in Electromagnetics Research Symposium, 1997)
The present work arose from a requirement of accurate time domain modeling of inter- connections in multichip modules (MCM's). As is the case with similar methods, the Transmission-Line-Matrix (TLM) method provides the feasibility to handle nearly any geometry and is not restricted to planar geometries. However, the modeling of circuits consisting of elements with strongly varying geometrical dimensions such as thin layers is not suitable for a conventional discretization due to limited computational resources. Also the use of graded meshes is very limited since the dispersion characteristic of these meshes becomes worse. For metalic layers surface-impedance models may be used which yield accurate broadband frequency characteristics [3]. In general, a local mesh refinement is required to increase the spatial resolution. Such subgridding techniques enable the mesh to carry for details, which could not be resolved by a coarse mesh. The combining of fine and coarse meshes requires for a careful investigation at the interface. In [1] the following conditions are postulated for the coarse mesh/fine mesh interface: energy conservation (i), charge conservation (ii), zero reflection (iii) and zero delay (iv). In the subgridding model, proposed by [1] the wave amplitudes incident from the coarse mesh to the fine mesh are kept constant during the time step within the coarse mesh. This introduces some lag in the interfering of the sub meshes. In contrary, we use a recursive description, in which also the incident pulses from the coarse mesh are adjusted to the updated field situation on the fine mesh. In this improved subgridding model additional transforma- tions between the wave amplitudes and the field quantities are necessary, which can be done exactly only at the cell boundaries of the TLM nodes. Our algorithm is completely embedded in a TLM simulation package utilizing distributed computing making best use of the available resources [2]. We use the Parallel Virtual Ma- chine (PVM) as an environment for the distributed computing. The simulations are done within clusters of interconnected workstations and parallel computers. The subgridding model was tested for several scenarios and has been approved to satisfy the previously mentioned conditions. The method was applied to the simulation of interconnections in multichip modules, where the thickness of some intermediate layers was more than one order of magnitude smaller than the transversal dimensions of the remaining elements. The improved subgridding approach opens a wide range of applications for the TLM method and benefits inherently from the flexibility of distributed computing.
elib2cris::1512001600,isele1997

A Novel Technique for Determining Kernels of Volterra Based Behavioral Models for RF Amplifiers - Zorn, Stefan; Ehm, Henning; Weigel, Robert (38th European Microwave Week, 2008)
elib2cris::1512001600,zorn2008

A novel test device to characterize SAW acoustomigration - Ruile, Werner; Raml, Gerhard; Springer, Andreas; Weigel, Robert (IEEE Ultrasonics Symposium 2000, 2000)
Acoustomigration is a well-known problem for SAW-filters used for front-end applications in modern mobile communications systems. Many different metallizations have been investigated so far to overcome this problem. Because of different test devices, testing conditions, and failure criteria it is difficult to compare and discuss the experimental results obtained by different research groups. Moreover, the electrical performance is changing during testing and thus the stress level in the metallization changes, too. In the present work, we propose a method to test metallizations independently of the influence of the SAW test device with defined and constant stressing of the metallization during the measurement campaigns. The device is a two-port resonator with a metallized area in the cavity. Migration patterns occur only in this fully metallized area whereas all electrodes remain unaffected. The irreversible shift of the resonance frequency due to acoustomigration can be evaluated as a function of temperature and input power during testing. Thus, the acoustomigration-related quality of different metallizations can be characterized in a well-defined manner
elib2cris::1512001600,ruile2000
Keywords: Characterization; SAW

A Novel Uniplanar Transition Coplanar Waveguide to Rectangular Waveguide - Nagy, Oliver; Heide, Patric; Kerssenbrock, Thomas; Springer, Andreas; Weigel, Robert (IEEE European Microwave Conference, 2001)
For communication modules a rectangular waveguide interface is often required. A novel transition between a rectangular waveguide and a coplanar waveguide is presented in this paper. The transition is fully uniplanar, making it very interesting for module applications. The benefits are the fairly simple manufacturing process and the reduced effort on the substrate side since no vias are needed. An insertion loss of 1.2 dB is obtained with broadband behavior over the waveguide frequency range.
elib2cris::1512001600,nagy2001a
Keywords: Coplanar waveguide; transition; rectangular waveguide; uniplanar

A Novel, W-Band Microwave Based Contactless Test Method for Mechanical Sensitivity Analysis of MEMS - Oesterle, Florian; Vinci, Gabor; Weigel, Robert; Kölpin, Alexander (IEEE International Microwave Symposium, 2013)
The desired functionality of Micro Electro Mechanical Systems (MEMS) suffers from the influence on the nominal stress level of the mechanical components, e.g. by deviating manufacturing process parameters. Therefore, appropriate methods for testing mechanical parameters of MEMS is a key issue. The focus is on contactless techniques, short measurement time, accurate repeatability, and inline integration in manufacturing environments for mass production. Depending on the configuration of the device components, a couple of methods, such as optical interferometry, electrical impedance measurements and system level sensitivity tests are nowadays in use. This article presents a novel method for contactless testing of mechanical sensitivity of MEMS devices based on W-band microwave interferometry. Results of measurements at 90GHz are shown. The excellent detection of the test parameter verifies the feasibility and enormous potential of this proposed method.
elib2cris::1512001600,oesterle2013
Keywords: Microelectromechanical Systems; Contactless Testing; Microphones; Mechanical Sensitivity; Microwave Interferometry; W-band

A Novel, Wide Angle, High Resolution Direction-Of-Arrival Detector - Vinci, Gabor; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (European Microwave Week (EuMW) 2011, 2011)
Direction-Of-Arrival (DOA) detection is a demanding task for a wide range of applications where high accuracy, robustness, small size, and low cost are important requirements. An innovative Six-Port based DOA detector is hereby presented. Several applications benefit from the advantages of this new interferometric detection principle. A new high resolution dual Six-Port based detector is presented featuring among the advantages provided by the interferometric principle also a wide angle of detection as well as an increased dynamic range and new digital signal processing strategies.
elib2cris::1512001600,vinci2011b
Keywords: Accuracy; Calibration; Detectors; Polynomials; Radio frequency; Receiving antennas

An Overview of Wireless Internet Access Technologies - Huemer, Mario; Gugler, Wolfgang; Springer, Andreas (An Overview of Wireless Internet Access Technologies, 2003)
elib2cris::1512001600,huemer2003

Anregungen fuer symmetrisch kondensierte TLM-Knoten zur Vermeidung stoerender Gittermoden - Lindenmeier, Stefan; Isele, Bertram; Weigel, Robert; Russer, Peter (Kleinheubacher Tagung, 1995)
elib2cris::1512001600,lindenmeier1995

An RF Voltage Detector with Low Harmonic Feedback for Antenna Tuning Switches - Özdamar, Oguzhan; Hagelauer, Amelie Marietta; Weigel, Robert; Solomko, Valentyn (2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems, COMCAS 2019, 2019)
A voltage detector with reduced harmonic feedback into the sensed RF path for the use in highly-linear, high-voltage antenna tuning switches is demonstrated. The reduction of harmonic content is achieved by adding linearization elements to the charge-pump-based rectifier, which are activated at large input RF voltage amplitudes. The detector has been implemented and tested in hardware with two high-voltage switches. The ICs were manufactured in Infineon 130nm RF switch process. The measured voltage detector exhibits a linear transfer characteristic and generates feedback harmonics level, which is below the nonlinearities of the intrinsic RF switch. The proposed detector targets voltage monitoring function, particularly in the RF switches for antenna tuning applications.
CRIS-Team Scopus Importer:2020-02-21
Keywords: Antenna tuning; charge pump; harmonics; high-voltage switch; linearity; RF switch; voltage detector

Antenna and Package Design for 61 GHz and 122 GHz Radar Sensors in Embedded Wafer-Level Ball Grid Array Technology - Frank, Martin; Reißland, Torsten; Lurz, Fabian; Völkel, Matthias; Lambrecht, Franziska; Kiefl, Stefan; Ghesquiere, Pol; Ng, Herman; Kissinger, Dietmar; Weigel, Robert; Kölpin, Alexander (IEEE Transactions on Microwave Theory and Techniques, 2018)

Antenna Aperture Tuning with High-Voltage Bulk-CMOS Switch-Based RF Capacitor - Solomko, Valentyn; Özdamar, Oguzhan; Wang, Kun; Pfuhl, Nadine; Thomas, Anthony; Weigel, Robert; Hagelauer, Amelie Marietta (PROCEEDINGS OF THE 2019 IEEE ASIA-PACIFIC MICROWAVE CONFERENCE (APMC), 2019)
CRIS-Team WoS Importer:2020-09-25

Antenna Array in eWLB for 61 GHz FMCW Radar - Pour Mousavi, Seyed Mehran; Wojnowski, Maciej; Agethen, Roman; Weigel, Robert; Hagelauer, Amelie Marietta (Asia-Pacific Microwave Conference Proceedings (APMC), 2013)
elib2cris::1512001600,pourmousavi2013c

Antenna Design and Characterization for a 61 GHz Transceiver in eWLB Package - Pour Mousavi, Seyed Mehran; Wojnowski, Maciej; Agethen, Roman; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE European Microwave Integrated Circuit Conference, 2013)
elib2cris::1512001600,pourmousavi2013b

Antenna Diversity Techniques for a Single Carrier System with Frequency Domain Equalization – An Overall System Analysis - Witschnig, Harald; Strasser, Gernot; Weigel, Robert; Springer, Andreas (International Workshop on Multi-Carrier Spread Spectrum and Related Topics, 2003)
In this work we investigate the possibilities of combining diversity techniques with a Single Carrier System with Frequency Domain Equalization (SC/FDE), as future transmission concepts will also be judged by their possibilities to be combined with multiple antennas. Concepts of multiple antennas allow either a significant performance gain through diversity or significant higher capacity based on spacial multiplexing. In this contribution we will point out the excellent possibilities of SC/FDE to be combined with diversity techniques, as the process of the equalization itself can be combined with receive diversity as well as with space time block (STBC) decoding. This combination gives a reduced signal processing complexity as well as the expected enormous performance gain. Especially the concept of STBC allows an advantageous combination with SC/FDE as both are based on a blockwise processing that can be formulated advantageously in the frequency domain. Our simulation results are based on the parameters of the IEEE 802.11a standard.
elib2cris::1512001600,witschnig2003b

Antenna Setup for Future Joint Radar-Communications – Characteristics and Mounting Positions - Lübke, Maximilian; Fuchs, Jonas; Dubey, Anand; Frank, Martin; Franchi, Norman; Lurz, Fabian (Advances in Radio Science : Kleinheubacher Berichte, 2023)

An Ultra Broadband Multi-Tone Six-Port Radar for Distance Measurements in K-Band Waveguides - Heining, Simon; Michler, Fabian; Scheiner, Benedict; Hassan, Emadeldeen; Kölpin, Alexander; Weigel, Robert; Lurz, Fabian (IEEE Radio and Wireless Symposium, 2020)
Continuous wave (CW) radars show an excellent performance in high precision distance measurements. However, when it comes to absolute distances, the ambiguity of these systems is a notable issue. To extend the unambigous range beyond λ/2, dual tone systems have been presented using two spaced CW measurements. In this paper, a broadband multi-tone radar operating in the K-band using six-port technology is presented. By using more than two frequencies, the unambigous range can be further enlarged. The radar system presented in this paper is able to perform 5-FSK measurements within a bandwidth of 5.5GHz delivering an update rate of 25Hz and a precision of 37.96µ

An Ultra-Versatile Massive MIMO Transceiver Testbed for Multi-Gb/s Communication - Gröschel, Patrick; Hehn, Markus; Sippel, Erik; Schober, Robert; Weigel, Robert; Vossiek, Martin; Carlowitz, Christian (2019 IEEE 2nd 5G World Forum (5GWF), 2019)
Massive multiple-input multiple-output (MIMO) communication has gained huge attention throughout the last years as a key technology for fifth generation mobile communication systems, because they enable wide area coverage along with ultra-high data rates and low bit energy. Furthermore, for a high number of antennas, communication theory predicts nearly optimal performance using basic linear detection and precoding schemes. However, realizing such large-scale arrays (say 100 elements or more) is non-trivial and costly and hence, only few of them are available for public research. Most often, existing solutions are limited to the current mobile communication standards. We therefore propose the design and implementation of a low-cost ultra-versatile 120-antenna massive MIMO testbed applicable both in communication and localization research. An instantaneous bandwidth of 150 MHz at a center frequency of 5.8 GHz is covered. An indoor verification measurement with 24 parallel transmissions and a bandwidth of 125 MHz achieved a sum-rate of 22.8 Gb/s with only 1.02 % bit error rate resulting in an outstanding equivalent error-free spectral efficiency of 167.2 bit/s/Hz.<br
Keywords: Radio frequency; Antenna arrays; Antenna measurements; OFDM; Transceivers

An ultrawideband antenna for FMCW-radar positioning systems - Vinci, Gabor; Waldmann, Benjamin; Weigel, Robert; Kölpin, Alexander (5th European Conference on Antennas and Propagation, 2011)
The imminent widespread commercial deployment of ultra-wideband (UWB) systems has sparked renewed interest in the subject of ultra-wideband antennas. A field where UWB systems are required is local positioning. These solutions, based on Frequency Modulated Continuous Wave (FMCW) radar principle require a broadband RF system to allow the radar to sweep the entire frequency ramp. For these purposes, low-cost, compact and robust UWB antennas are needed. This document describes a novel planar UWB antenna of the type “Monopole-Over-Ground”, that delivers good performance in the large frequency range of interest, low cost, small dimensions and robustness
elib2cris::1512001600,vinci2011a

An Ultra-Wideband Coupled-Line Balun Using Patterned Ground Shielding Structures - Sewiolo, Benjamin; Hartmann, Marcus; Waldmann, Benjamin; Weigel, Robert (IEEE Radio and Wireless Symposium (RWS), 2008)
elib2cris::1512001600,sewiolo2008

An Ultra-Wideband Local Positioning System for Highly Complex Indoor Environments - Waldmann, Benjamin; Ebelt, Randolf; Vossiek, Martin; Weigel, Robert (International Conference on Localization and GNSS (ICL-GNSS) 2012, 2012)
In this paper a novel approach for a high precision local positioning radar using an ultra-wideband (UWB) technique is presented. The concept is based on the standard frequency modulated continuous wave (FMCW) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. Besides the well known advantages of a FMCW radar, the proposed system implies a wide frequency bandwidth. With this concept, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for 1D, 2D, and 3D localization applications for complex industrial environments. Investigations on the achievable performance of such an UWB system show very promising results and are presented within this paper. A prototype system was fabricated which operates at the center frequency of 7.5 GHz utilizing a bandwidth of 1 GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a standard deviation and absolute accuracy in the low centimeter range, even in challenging multipath environments. © 2012 IEEE.
UnivIS-Import:2015-04-16:Pub.2012.tech.IE.LEH.anultr

An ultra wideband positioning system enhanced by a short multipath mitigation technique - Waldmann, Benjamin; Götz, Alexander; Weigel, Robert (Wireless Sensing, Local Positioning, and RFID, 2009. IMWS 2009. IEEE MTT-S International Microwave Workshop on, 2009)
In this paper an approach for high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. In this way, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for 1D, 2D and 3D localization. A prototype was built which operates at a center frequency of 7.5 GHz utilizing a bandwidth of 1 GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a standard deviation down to 6 mm. Additionally, we studied the effects of short multipath propagation and present simulation results for an applicable mitigation technique.
elib2cris::1512001600,waldmann2009
Keywords: Ultra Wideband; FMCW; Indoor Positioning; Radar Navigation; Neural Networks; Multipath Channels

An unconventional VNA-based time-domain waveform load-pull test bench - Teppati, Valeria; Pinarello, Sandro; Ferrero, Andrea; Müller, Jan-Erik (Microwave Conference Proceedings (APMC), 2010 Asia-Pacific, 2010)

A particle swarm optimizer for tuning a software-defined, highly configurable wireless power transfer platform - Schütz, Martin; Georgiadis, Apostolos; Collado, Ana; Fischer, Georg (Wireless Power Transfer Conference (WPTC), 2015 IEEE, 2015)

A Permittivity Characterization Method by Detuned Ring-Resonators for Bulk Materials up to 110 GHz - Talai, Armin; Steinhäußer, Frank; Bittner, Achim; Schmid, Ulrich; Weigel, Robert; Kölpin, Alexander (44th European Microwave Conference (EuMC), 2014)
An accurate characterization of microwave materials is essential for reliable high frequency circuit design. This paper presents a measurement setup, which enables a quick and accurate determination of the relative permittivity of dielectric bulk materials up to 110 GHz. A ring-resonator is manufactured on a well characterized substrate dealing as reference resonator. The Material Under Test (MUT) is placed on top of the ring, which increases the effective permittivity and therefore introduces a shift of the resonance frequency of the resonator. Electromagnetic field simulations with different heights and relative permittivities of the MUT provide a lookup table for the measured resonance frequencies. The functionality of the proposed measurement setup is validated by measurement results of different MUTs.
elib2cris::1512001600,talai2014f
Keywords: Bulk material; detuned resonator; frequency shift; material characterization; permittivity; ring resonator

A Permittivity Sensitive Phase-Locked Loop Based on a Silicon-Integrated Capacitive Sensor for Microwave Biosensing Applications - Nehring, Johannes; Bartels, Melanie; Weigel, Robert; Kissinger, Dietmar (IEEE Topical Conference on Biomedical Wireless Technologies, Networks & Sensing Systems, 2015)
elib2cris::1512001600,nehring2015

A phase II, randomized, study of weekly APG101+reirradiation versus reirradiation in progressive glioblastoma - Wick, Wolfgang; Fricke, Harald; Junge, Klaus; Kobyakov, Grigory; Martens, Tobias; Heese, Oliver; Wiestler, Benedikt; Schliesser, Maximilian G.; Von Deimling, Andreas; Pichler, Josef; Vetlova, Elena; Harting, Inga; et al. (Clinical Cancer Research, 2014)
Purpose: Preclinical data indicate anti-invasive activity of APG101, a CD95 ligand (CD95L)-binding fusion protein, in glioblastoma.
CRIS-Team Scopus Importer:2023-03-08

A Physically Based Reliability Modelling Framework for nm-CMOS RF Devices and Circuits undergoing RF Stress - Cattaneo, Andrea (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

A Planar 24 GHz Switched-Beam Antenna Based on PIN Diodes for Remote Sensing Applications - Michler, Fabian; Scheiner, Benedict; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (2018 Asia-Pacific Microwave Conference, 2018)
This paper presents a planar switched-beam antenna for remote sensing applications at 24 GHz. The antenna consists of 9x8 radiating patches, arranged as nine linear arrays that are connected by phase shifters based on PIN diodes, which allow to quickly switch the main lobe between two symmetric states by using a small control current. The single array elements were designed and simulated in CST Microwave Studio and the array feed network including the phase shifters was analyzed using Keysight ADS. Measurements of all individual components and the final array antenna were taken to confirm the simulations and to prove the concept.<br

A Planar Reconfigurable Focal Plane Array Antenna for 24 GHz - Sporer, Michael; Weigel, Robert; Kölpin, Alexander (IEEE International Microwave Symposium, 2016)
This paper presents a reconfigurable focal plane array (FPA) for lens or reflector based antenna systems in the 24 GHz ISM band. The FPA consists of five equal uniformlyspaced antenna elements with switchable polarization, fabricated on a four layer substrate using conventional low-cost PCB technology. For compactness and increased bandwidth, the design is based on aperture-coupled patch radiators on top of the substrate, each embedded in a cavity in order to reduce mutual coupling. Feeding is done by means of two orthogonal H-shaped slots which are excited by microstrip transmission lines etched on the bottom layer. A discrete pin-diode single pole, double throw (SPDT) switch directly below the patch allows for polarization control and facilitates a compact element size of 10mm x 10 mm including the cavity walls. Another discrete pin-diode SP5T switch allows the selection of one of the five FPA elements at a time.
elib2cris::1512001600,sporer2016
Keywords: focal plane array; polarization control; pin-diode switches; aperture coupling

A Planar V-Band Antenna for Wideband Radar and Communication on Low-Cost PCB Substrate - Peters, Sebastian; Faghih-Naini, Samira; Erhardt, Stefan; Reißland, Torsten; Weigel, Robert (IEEE Radio and Wireless Symposium (RWS), 2023)
A rectangular microstrip antenna with a resonant frequency of 60.5 GHz and a bandwidth of 4 GHz is proposed and evaluated. The antenna is based on the low-cost substrate RO4350B and is designed to reduce costs for prototypes and small batch series by complying with design restrictions for inexpensive pooling offers by many manufacturers. The influence of manufacturing tolerances on the performance of the antenna is also investigated and minimized. Finally, an antenna is fabricated and measurements are compared with simulation

A Power-Aware Behavioral Model of a Five-State Phase-Frequency Detector - Glock, Stefan; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (A Power-Aware Behavioral Model of a Five-State Phase-Frequency Detector, 2011)
This paper introduces a power-aware behavioral modeling approach for analog components. A Verilog-A behavioral model, which considers the component’s current consumption, is created using circuit information obtained from transistorlevel simulation. Therefore, the model features high accuracy with the benefit of low computational effort. The concept can be applied to any analog component and enables the simulation of complex analog systems. The approach is practically applied to the design of a phase-frequency detector, which determines important characteristics of a PLL.
elib2cris::1512001600,glock2011a

A power saving jamming system for E-GSM900 and DCS1800 cellular phone networks for search and rescue applications - Zorn, Stefan; Maser, Matthias; Götz, Alexander; Rose, Richard; Weigel, Robert (IEEE Topical Conference on Wireless Sensors and Sensor Networks, 2011)
Recent statistics show an increase in environmental disasters, a fact which is also perceivable to the public as reports of avalanches, earthquakes and landslides mount in media coverage. Search and Rescue with modern localization techniques consequently attracts attention from scientific and industrial sides. This paper introduces one part of the I-LOV project, endorsed by the German Federal Ministry of Education and Research. In this project partners from relief organizations, universities and industry investigate enhancements to disaster handling and victim rescue. One possible option is to take advantage of the fact, that a lot of people own a mobile phone today. To locate a person by his or her mobile phone requires to take over the phone by an own Base Transceiver Station (BTS). Jamming all other networks is one option to achieve that. This paper will introduce a new Field Programmable Gate Array (FPGA) based jamming system which consumes little power and disturbs only small parts of the GSM spectrum but reliably cuts all connections between mobile stations (MS) and existing BTS.
elib2cris::1512001600,zorn2011

A power sensor unit for the localization of GSM mobile phones for search and rescue applications - Zorn, Stefan; Bozsik, Gabor Josef; Rose, Richard; Götz, Alexander; Kölpin, Alexander; Weigel, Robert (IEEE Sensors, 2011)
Recent statistics show an increase in environmental disasters, a fact which is also perceivable to the public as reports of avalanches, earthquakes and landslides mount in media coverage. Recent examples are Haiti 2010 and Fukushima 2011. Search and Rescue with modern localization techniques consequently attracts attention from scientific and industrial sides. This paper introduces a field strength measurement unit, which is part of the I-LOV project1. In this project partners from relief organizations, universities, and industry investigate enhancements in disaster handling and victim rescue. One possible option is to take advantage of the fact that most people own a mobile phone today and take it with them the whole day. To locate a person by his or her mobile phone requires to find the maximum of its radiated field strength. This paper will show a new power sensor unit for GSM signals. The complete design flow from requirements considerations to measurement results will be demonstrated. A dynamic range of 107 dB is only one of the remarkable outcomes.
elib2cris::1512001600,zorn2011a
Keywords: cellular radio; disasters; earthquakes; geomorphology; mobile handsets; sensor placement; statistical analysis; GSM

Application of Model Order Reduction to Investigation of Power Distribution on PCB Level - Steinmair, Gernot; Unger, Bernd; Weigel, Robert (Progress in Electromagnetic Research Symposium, 2003)
elib2cris::1512001600,steinmeir2003

Application of SAW matched filters for time code division multiple access (TCDMA) systems - Zenzinger, Alesander; Zhang, Zhongping; Seifert, Franz; Weigel, Robert (IEEE 4th International Symposium on Spread Spectrum Techniques and Applications (ISSSTA), 1996)
elib2cris::1512001600,zenzinger1996

Application of X-parameters in studying nonlinearities in BAW and SAW Filters - Chauhan, Vikrant; Liang, Yunshi; Liao, Yucheng; Silva, Victor; Weigel, Robert; Hagelauer, Amelie Marietta (German Microwave Conference, 2018)

Appropriate Methods to Suppress Spurious FBAR Modes in Volume Production - Link, Andreas; Schmidhammer, Edgar; Heinze, Habbo; Mayer, Markus; Bader, Bernhard; Weigel, Robert (International Microwave Symposium, 2006)
Standards like CDMA in combination with the US PCS band impose challenging demands on the duplexer unit in the RF circuit of mobile phones. FBAR filters are candidates to fulfil the latest cutting-edge requirements for temperature stability, insertion loss, power durability, bandwidth, and filter skirts. Unfortunately, these filters suffer from spurious resonator modes. In this work we have investigated several suppression methods, which are capable of being applied to volume production
elib2cris::1512001600,link2006
Keywords: Acoustic resonator filters; Acoustic resonators; BAW; FBAR; spurious modes; apodization; lateral edge design

A practical beamsteering algorithm with low phase fluctuation for WCDMA/HSUPA uplink using transmit power control bits as feedback - Schröter, Simon; Weigel, Robert; Fischer, Georg; Kölpin, Alexander (19th International Conference on Microwave Radar and Wireless Communications (MIKON), 2012, 2012)
So called open loop transmit diversity algorithms for the uplink of HSPA are a topic of recent studies within the 3rd Generation Partnership Project (3GPP). These algorithms use the power control commands of the fast power control mechanism as a feedback information to iteratively determine the antenna weights, thus making them compatible with existing networks and procedures. In this paper, a novel practical beamsteering algorithm is presented. Simulations show, that the transmit power at the UE terminal can be reduced by 3.28 dB compared to the reference case of only one transmit antenna, thus improving the UE's battery life. Moreover, the novel algorithm exhibits a significantly lower rate of change of the transmitted signal's absolute phase than the algorithms presented within the 3GPP studies, which means less irritation to the receiver at the Node B.
elib2cris::1512001600,schroeter2012

A Pulsed Frequency Modulated Ultra Wideband Technique for Indoor Positioning Systems - Waldmann, Benjamin; Gulden, Peter; Vossiek, Martin; Weigel, Robert (Frequenz, 2008)
In this paper a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. Besides the well knowen advantages ifa FMCW radar the proposed system implies a wide frequency bandwidth. With this concept, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for 1D, 2D, and 3D localization. A prototype was fabricated which operates at the center frequency of 7.5 GHz utilizing a bandwidth of 1 GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a low standard deviation.
elib2cris::1512001600,waldmann2008
Keywords: FMCW; Indoor navigation; Radar position measurement; Ultra wideband

A Quad-Core 60 GHz Push-Push 45 nm SOI CMOS VCO with -101.7 dBc/Hz Phase Noise at 1 MHz offset, 19 % Continuous FTR and -187 dBc/Hz FoMT - Rimmelspacher, Johannes; Weigel, Robert; Hagelauer, Amelie Marietta; Issakov, Vadim (European Solid-State Circuits Conference (ESSCIRC), 2018)
This paper presents a 60 GHz Quad-Core push-push VCO in 45 nm partially depleted Silicon-on-Insulator (SOI) CMOS. The measured phase noise (PN) at 60.5 GHz is −101.7 dB/Hz at 1 MHz offset from carrier. The continuous frequency-tuning range (FTR) is 19 %. The Quad-Core VCO consumes only 40 mW DC power. The complete circuit including fundamental and second harmonic (H2) output buffers draws 110 mA from a single 1 V supply. The VCO cores are coupled via resonant-tank transformers. A similar transformer-coupled Dual-Core VCO is fabricated and measured to prove the relative PN improvement between Dual-Core and Quad-Core topology. The total area of the Quad-Core VCO excluding pads is 0.1 mm
Keywords: millimeter-wave; wideband; silicon-on-insulator; CMOS technology; System-on-Chip

A Radar-Based Vital Sign Sensing System for In-Bed Monitoring in Clinical Applications - Michler, Fabian; Shi, Kilin; Schellenberger, Sven; Lenhard, Thilo; Dassel, Florian; Scheiner, Benedict; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (German Microwave Conference 2020, 2020)

Architectural benefits of wide bandgap RF power transistos for frequency agile basestation systems - Fischer, Georg (Annual Wireless and Microwave Technology Conference, 2004)
The variety of standard - frequency band combinations with mobile communication systems is increasing. This has led to the request for software radio basestations that offer Multiband and Multistandard capability. Multiband capability is offered through frequency agile basestation systems that can be reconfigured to operate at different frequency bands and different standards, thus providing a flexible air interface. This paper focuses on how specific characteristics of wide band gap RF power transistors at device level map to benefits at architectural level with those frequency agile systems.
elib2cris::1512001600,fischer2004

Architecture Optimization and Implementation of a Radio Receiver wiht a Multistage Spectrum Sensing Techniques as Part of a Low-Cost Spectrum Sensing Grid - Rieß, Steffen (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)

Area-Efficient Fully Integrated Dual-Band Class-E/F Power Amplifier with Switchable Output Power for a BPSK/OOK Transmitter - Söll, Christopher; Röber, Jürgen; Milosiu, Heinrich; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE International Symposium on Circuits and Systems, 2017)
This paper presents a novel area-efficient dual-band class-E/F power amplifier (PA) with switchable output power. It is targeted to work in a BPSK/OOK transmitter in smart facility applications like an autarkic asset-tracking system based on small sensor nodes. The amplifier is able to operate at both 434MHz and 868MHz without the need for additional inductors. The output power settings at 868MHz are controllable between -1.79dBm and -24.61dBm at 4.96mA and 1.43mA current consumption, respectively. The whole circuit including all inductors and the matching network in front of the antenna consumes only 0.9mm2 chip area and is fully integrated in a 180nm CMOS process together with a VCO and a PLL.
elib2cris::1512001600,soell2017a
Keywords: Class-E/F Power Amplifier; Dual-Band; Switchable Output Power; Asset-Tracking System

A Reconfigurable MIMO System for High-Precision FMCW Local Positioning - Gierlich, Roland; Hüttner, Jörg; Ziroff, Andreas; Weigel, Robert; Huemer, Mario (IEEE Transactions on Microwave Theory and Techniques, 2011)
In this paper, a highly accurate local positioning system is presented that is based on linear frequency-modulated continuous-wave signals in the 5.8-GHz industrial-scientific-medical band. The developed system allows for much higher operating distances than leading ultra-wideband local positioning systems, while it provides the same or even better accuracy. This is achieved by a novel multiple-input multiple-output (MIMO) measurement concept that enables the receiving unit to control the beam patterns of the receiving and the transmitting antenna arrays by a coherent combination of the received signals. In this way, interfering multipath components are suppressed, leading to a significantly reduced ranging error. Furthermore, the angle of arrival and the angle of departure are determined from the MIMO datasets using super-resolution direction-finding techniques. For position determination, both range and angle information are exploited. Extensive measurements with the MIMO system in different indoor environments show that the position error can be reduced by up to 80% compared to an equivalent single-antenna setup.
elib2cris::1512001600,gierlich2011
Keywords: MIMO communication; antenna arrays; direction-of-arrival estimation; receiving antennas; transmitting antennas; ultra wideband communication; MIMO datasets; angle of arrival; angle of departure; frequency 5.8 GHz; high-precision FMCW local positioning system; indoor environments; industrial-scientific-medical band; interfering way; multipath components; linear frequency-modulated continuous-wave signals; multiple-input multiple-output measurement concept; received signals; receiving antenna arrays; reconfigurable MIMO system; single-antenna setup; super-resolution direction-finding techniques; transmitting antenna arrays; ultrawideband local positioning systems; Beam steering; Chirp modulation; Distance measurement; MIMO radar; Multipath channels; Beam steering; chirp modulation; distance measurement; multipath channels; multiple-input multiple-output (MIMO) radar

A Reconfigurable MIMO System for High Precision FMCW Radiolocation - Gierlich, Roland (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)

A Reconfigurable Vector Signal Generator with Two Phase Controlled SigmaDelta-Synthesizers - Ibrahim, Muhammad Irfan (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2011)

A Resonant Substrate Integrated Waveguide Measurement System for True Relative Permittivity Extraction of PCB Materials up to 90 GHz - Lau, Isabella; Michler, Fabian; Talai, Armin; Weigel, Robert; Kölpin, Alexander (IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes (IMWS-AMP), 2018)
This paper presents a resonant measurement method based on substrate integrated waveguide cavities for determination of the true relative permittivity of a PCB material. The sensor is manufactured on the unknown PCB material and in contrast to existing, comparable methods, the extraction process takes into account the metal roughness. The proposed method does not require any reference materials or sensors on different PCB thicknesses. This paper contains considerations regarding the design and simulation as well as measurement results of the sensor system. To validate the measurement system, the extracted relative permittivity values of the RO4350B substrate over the frequency range of 10 GHz to 90GHz are presented.<br

A Review and Comparative Study of On- and Off-Body Performance of Platform-Tolerant UHF RFID Tag Antennas - Gardill, Markus; Finkenzeller, Klaus; Hinz, Walter; Fischer, Georg; Weigel, Robert; Kölpin, Alexander (8th International Conference on Body Area Networks, 2013)
This paper addresses the remote identifying of human subjects by means of UHF RFID tags. In particular, we provide a comprehensive review of recent approaches in the design of compact, platform-tolerant UHF RFID antennas for on- as well as off-body applications. We first categorize previously published antenna designs and interrelate the various approaches. We then provide detailed simulation results for several selected design approaches, and compare the performance of the proposed antenna structures when used in free-space, placed in proximity to a homogenous phantom half-space model, and when used on or in proximity to a layered elliptical body model. We provide a comparative study by evaluating all approaches using the same figure of merits, which are the power transfer and the estimated read range, evaluated in exactly the same simualtion environment for all approaches.
elib2cris::1512001600,gardill2013f

A review of cyclically extended single carrier transmission with frequency domain equalization for broadband wireless transmission - Huemer, Mario; Koppler, Alois; Weigel, Robert; Reindl, Leonhard (European Transactions on Telecommunications, 2003)
In this paper we investigate the concept of cyclically extended single carrier transmission with frequency domain equalization (SC/FDE). We present a detailed mathematical derivation of fast Fourier transform (FFT) based optimum linear receivers, and we describe the signal processing steps of an efficient FDE implementation structure. With a specific system design, where the parameters have been adapted to the IEEE 802.11a and Hiperlan/2 orthogonal frequency division multiplexing (OFDM) based wireless local area network (WLAN) standards in the 5 GHz band, we demonstrate that SC/FDE is a powerful candidate for high speed wireless future applications.
elib2cris::1512001600,huemer2003b

A Review of Integrated Systems and Components for 6G Wireless Communication in the D-Band - Maiwald, Tim; Li, Teng; Hotopan, George Roberto; Kolb, Katharina; Disch, Karina; Potschka, Julian; Haag, Alexander; Dietz, Marco; Debaillie, Bjorn; Zwick, Thomas; Aufinger, Klaus; Ferling, Dieter; et al. (Proceedings of the IEEE, 2023)
The evolution of wireless communication points to increasing demands on throughput for data-intensive applications in modern society. Integrated millimeter-wave systems with electrical beam-steering capabilities are promising candidates for wireless technologies of the future and are currently the subject of widespread academic and commercial research. The D -band, ranging from 110–170 GHz, offers high aggregate bandwidths (BWs), low atmospheric absorption, and multi-GHz operation at amenable fractional BWs. It, therefore, has the potential to foster efficient, highly integrated wireless-communication systems with data rates approaching 100 Gb/s. This article reviews all aspects of hardware integration against the backdrop of an extensive literature review and outlines the challenges and possible solutions for practical 6G wireless systems in the D -band. To this end, this article covers a number of related topics in depth, which includes system definition, possible radio architectures and array configurations, the scope and potential of integrated circuit (IC) technologies, the design and characterization of key circuit blocks, advances in antenna and packaging technologies for high-frequency systems, and an overview of measurement techniques currently employed at D -band frequencies. A system-level study based on radio-link simulations of different single-carrier quadrature amplitude modulation (QAM) schemes is presented, which quantifies that the impact physical nonidealities, such as signal-to-noise ratio, phase noise, intermodulation distortion, and amplitude and phase imbalances in quadrature signal paths, have on bit-error rates in broadband D -band communication systems. This is followed by a comparative assessment of different arrayed-system configurations that include traditional phased arrays, the use of polarization diversity for the transmission of different or identical data streams, and multiple input multiple output (MIMO) operation. The article also presents an overview of possible transceiver architectures for implementing beam-steering arrays and an outline of the associated tradeoffs. The beam-squinting effect seen in large arrays is also investigated in detail. On the implementation front, we present a comparison between different integrated-circuit technologies for high-frequency applications. These include CMOS and SiGe bipolar complementary metal oxide semiconductor (BiCMOS) heterojunction bipolar transistors (HBTs) in silicon technologies, and MOSFETs, HBTs, and HEMTs in III–V technologies, such as InP and GaAs. Implementation challenges are then addressed, and these include the design of high-frequency circuits in the latest IC technologies, current advances in antenna and packaging technologies, and emerging solutions for hybrid integration. The article also details the design and characterization of critical D -band transceiver circuit blocks, namely, power and low-noise amplifiers, mixers, phase shifters, passive components for quadrature-phase generation, and radiators exploring hybrid antennas, which we have developed over the course of the past five years. These results compliment the literature survey with comparisons with state-of-the-art designs and are applied to radio-link simulations to predict the performance of practicable wireless links.
CRIS-Team Scopus Importer:2023-03-17
Keywords: 6G; 6G mobile communication; D -band; beyond 5G; Broadband antennas; characterization; circuit design; communication; high-speed; Integrated circuits; packaging; prototyping; semiconductor technologies; Throughput; transceiver architectures; Transceivers; Wireless communication; Wireless sensor networks

A Review on Six-Port Radar and Its Calibration Techniques - Linz, Sarah; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (22nd International Microwave and Radar Conference (MIKON), 2018)

Arithmetical elimination of superimposed interference modulation in laser spectroscopic gas concentration measurements - Weigel, Robert; Hartmann, Alexander; Strzoda, Rainer; Schrobenhauser, Robert (European Conference on Solid-State Transducers, EUROSENSOR 2012, 2012)
A method for an arithmetical elimination of superimposed interference fringe modulations in laser spectroscopic sensor signals has been developed. It is based on analyzing the harmonic components of the Fourier spectrum calculated from the measured signal. The technique is especially suited for remote measurements including fringes with unknown modulation frequency. The effectiveness of the method is demonstrated by comparison of the results with classic least-square calculations of the gas concentration signal.
elib2cris::1512001600,weigel2012
Keywords: Gas concentration; interference; fringe; rejection; elimination

A Robust and Real-Time Capable Envelope-Based Algorithm for Heart Sound Classification: Validation under Different Physiological Conditions - Thalmayer, Angelika; Zeising, Samuel; Fischer, Georg; Kirchner, Jens (Sensors, 2020)
This paper proposes a robust and real-time capable algorithm for classification of the first and second heart sounds. The classification algorithm is based on the evaluation of the envelope curve of the phonocardiogram. For the evaluation, in contrast to other studies, measurements on twelve probands were conducted in different physiological conditions. Moreover, for each measurement the auscultation point, posture and physical stress were varied. The proposed envelope-based algorithm is tested with two different methods for envelope curve extraction: the Hilbert transform and the short-time Fourier transform. The performance of the classification of the first heart sounds is evaluated by using a reference electrocardiogram. Overall, by using the Hilbert transform, the algorithm has a better performance regarding the F1-score and computational effort. The proposed algorithm achieves for the S1 classification an F1-score up to 95.7% and in average 90.5 %. The algorithm is robust against the age, BMI, posture, heart rate and auscultation point (except measurements on the back) of the subjects. The ECG and PCG records are available from the authors.<br

A Robust Digital Predistortion Algorithm for 5G MIMO: Modeling a MIMO Scenario With Two Nonlinear MIMO Transmitters Including a Cross-Coupling Effect - Ackermann, Thomas; Potschka, Julian; Maiwald, Tim; Hagelauer, Amelie; Fischer, Georg; Weigel, Robert (IEEE Microwave Magazine, 2020)
Linearity, efficiency, and power consumption are the key figures of merit for modern communication system design as data rates increase toward millimeter-wave communication systems like 5G. A common problem is that both high linearity and efficiency are not simultaneously feasible in power amplifier (PA) design. Hence, when a PA is operated near saturation for highest efficiency, undesired harmonic and intermodulation distortions have to be taken into account. A transceiver comprises several circuit elements, such as a low-noise amplifier, mixer, and PA. In this transceiver chain, the PA usually exhibits the highest power consumption (i.e., it is worthwhile to maximize the efficiency of this circuit component to increase overall system performance).<br
Keywords: digtal-predistortion; power amplifier; DPD; MIMO; Cross-Talk; Linear

A Robust Light-Weight Protocol Stack for Data Transmission within Inductive Power Transfer Systems - Sanftl, Benedikt; Magel, Thomas; Trautmann, Martin; Weigel, Robert; Kölpin, Alexander (ApMediaCast2016 Asia Pacific Conference on Multimedia and Broadcasting, 2016)
elib2cris::1512001600,sanftl2016c
Keywords: IPT; Inductive Data Communication; protocol design; wireless communication; signal processing

A Robust SAW-Based Chirp pi/4 DQPSK System for Indoor Applications - Gugler, Wolfgang; Springer, Andreas; Weigel, Robert (International Conference on Communications, 2000)
elib2cris::1512001600,gugler2000

A robust ultra-broad-band wireless communication system using SAW chirped delay lines - Springer, Andreas; Weigel, Robert; Pohl, Alfred; Gugler, Wolfgang; Huemer, Mario; Reindl, Leonhard; Ruppel, Clemens; Seifert, Franz (IEEE Transactions on Microwave Theory and Techniques, 1998)
Design and performance of a low-cost wireless communication system for indoor and industrial environments are presented. The system is based on chirp-signal transmission to achieve a robust communication link. For the chirp expansion and compression, surface acoustic wave chirped delay lines fabricated from LiTaO3-X112rotY are used. Center frequency, bandwidth, and chirp rate are 348.8 MHz, 80 MHz, and ±40 MHz/μs, respectively. An optimized square-root weighting was chosen to reduce the sidelobes of the compressed pulse to -42 dB compared to the correlation peak. The chirp filters have been deployed in a hardware demonstrator for data rates of up to 5 Mb/s. Limiting factors for the data rate according to simulations and measurements are mainly intersymbol interferences due to the time overlapping of consecutive symbols and, to a lower extent, the multipath propagation
elib2cris::1512001600,springer1998d

A robust ultra broadband wireless communication system using SAW chirped delay lines - Weigel, Robert; Springer, Andreas; Huemer, Mario; Reindl, Leonhard; Ruppel, Clemens; Pohl, Alfred; Seifert, Franz; Gugler, Wolfgang (IEEE MTT-S International Microwave Symposium Digest, 1998)
Design and performance of SAW chirped delay lines on LiTaO3 -X112rotY for a wireless communication system are presented. Center frequency, bandwidth and chirp rate are 350 MHz, 80 MHz, and ±20 MHz/s, respectively. An optimized square-root weighting was chosen to reduce the sidelobes of the compressed pulse to -42 dB compared to the correlation peak. The chirp filters have been deployed in a hardware demonstrator for a wireless indoor communication system for data rates of a few Mbit/s. Limiting factors for the data rate according to simulations and measurements are mainly the intersymbol interference due to the time-overlapping of consecutive symbols and to a lesser extent the multipath propagation
elib2cris::1512001600,weigel1998a

Artificial Intelligence for Molecular Communication - Bartunik, Max; Kirchner, Jens; Keszöcze, Oliver (it - Information Technology, 2023)
Keywords: Molecular Communication; Demodulation; Convolutional Neural Network

A SAW-Based High-Speed Spread-Spectrum WLAN Using Chirp-pi/4 DQPSK Modulation - Koller, Rainer; Gugler, Wolfgang; Springer, Andreas; Weigel, Robert (IEEE International Ultrasonics Symposium, 2000)
elib2cris::1512001600,koller2000

A SAW Matched Filter Based Spread Spectrum Technique Based for Indoor Multiple Access Systems - Zhang, Zhongping; Seifert, Franz; Weigel, Robert (International Microwave Symposium Digest, 1995)
Surface Acoustic Wave (SAW) tapped delay lines and convolvers functioning as Matched Filters (MFs) are of superior advantages in broadband spread spectrum communication systems in comparison to digital signal processors. SAW MFs allow indoor systems to have a bandwidth larger than the coherence bandwidth of the indoor radio channel. A multiple access technique called Time Code Division Multiple Access (TCDMA) based on SAW MFs is proposed. Using Gold codes of length 128 as spreading codes, our uplink performance simulation results reveal the capacity of TCDMA in a typical indoor cell
elib2cris::1512001600,zhang1995c

A SAW shaping filter for high data rate MSK-encoding in a broadband DS-CDMA system - Zenzinger, Alesander; Morhart, Franz; Reindl, Leonhard; Weigel, Robert (IEEE MTT-S Symposium on Technologies for Wireless Applications Digest, 1997)
We report on two surface acoustic wave (SAW) shaping filters which generate a minimum shift keying (MSK) modulated signal by converting a BPSK modulated signal. The filters are intended to be used for modulators with high data rates, as it is necessary in broadband direct sequence code division multiple access (DS-CDMA) systems. One filter has been fabricated from a lithium tantalate (LiTaO3) substrate, and one from a quartz substrate. The filter on LiTaO3 fulfills all requirements dealing with spectrum shaping. However, the temperature range is not as wide as with quartz substrates due to the higher temperature coefficient of LiTaO3. The filter on quartz is very stable from the temperature coefficient point of view, but the insertion attenuation and spurious electromagnetic feedthrough are relatively high.
elib2cris::1512001600,zenzinger1997a
Keywords: Acoustic waves; Binary phase shift keying; Direct-sequence code-division multiple access; Filters; Lithium compounds; Modulation coding; Multiaccess communication; Signal generators; Surface acoustic waves; Temperature distribution

A Scalable 77 GHz Massive MIMO FMCW Radar by Cascading Fully-Integrated Transceivers - Och, Andreas; Pfeffer, Clemens; Schrattenecker, Jochen; Schuster, Stefan; Weigel, Robert (Proceedings of 2018 Asia-Pacific Microwave Conference, 2018)
Advanced Driver Assistance Systems (ADAS) as well as multiple industrial imaging applications highly benefit from increased angular resolution in millimeter-wave (mmW) phased-array radar systems. To achieve this, future radar systems will need a high amount of transmitter (TX) and receiver (RX) channels while at the same time being suitable for mass-production. Therefore we propose a concept to realize a scalable massive multiple-input-multiple-output (MIMO) radar system by cascading fully-integrated frequency-modulated continuous-wave (FMCW) transceivers, thus reducing system cost and complexity. Prototype hardware with 5 transceivers (TRXs) is built and tested under laboratory and application-near conditions. First results show an angular resolution of 2.4° in azimuth in good accordance to the simulations. Parked cars and their surrounding scenery in front of the radar module can be clearly distinguished.<br
Keywords: chirp radar; massive MIMO; millimeter wave radar; phased array radar; road vehicle radar

A Semi Double-Ridged quasi TE-Waveguide based Microwave Bulk Material Characterization System - Talai, Armin; Mann, Sebastian; Steinhäußer, Frank; Bittner, Achim; Schmid, Ulrich; Weigel, Robert; Kölpin, Alexander (IEEE MTT-S International Microwave Symposium (IMS), 2015)
Accurate microwave material characterization is essential for reliable high frequency circuit design. Therefore, various characterization techniques have been developed, comprising advantages and drawbacks for the respective conditions. In this paper, a material characterization system is presented, which enables a broadband measurement for both dielectric loss and relative permittivity of bulk substrates with variant geometrical dimensions. A semi double-ridged waveguide is used to measure the introduced phase shift and dampening due to a strip of material, allowing a combined evaluation of the complex permittivity by measurement and simulation.
elib2cris::1512001600,talai2015a
Keywords: Material Characterization; Phase Measurement; Ridged Waveguide; Relative Permittivity

A Semi-Physical Power Amplifier Behavioral Model Capable of Predicting Gain Expansion Effects - Glock, Stefan; Rascher, Jochen; Sogl, Bernhard; Ußmüller, Thomas; Müller, Jan-Erik; Fischer, Georg; Weigel, Robert (IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications, 2014)
A novel semi-physical power amplifier (PA) behavioral model (BM) that describes the input-output characteristic of PAs exhibiting gain expansion (GE) is introduced. The accurate prediction of GE is of particular importance because GE typically improves the power added efficiency (PAE) at high input powers. Though, GE impacts the spectral regrowth. Therefore, BMs that are capable of predicting GE, like the one introduced in this work, are highly desirable. In a case study, the proposed model is employed to predict the AM-AM distortions of a GaAs PA designed for LTE applications. Excellent agreement between measurement and simulation results is obtained. The computational efficient model allows system-level simulations of advanced transmitter systems in order to optimize their modes of operation.
elib2cris::1512001600,glock2014

A SiGe-Bipolar Down-Conversion Mixer for a UMTS Zero-IF Receiver - Pretl, Harald; Schelmbauer, Werner; Adler, Bernd; Maurer, Linus; Fenk, Josef; Weigel, Robert (Proceedings of the Bipolar/BiCMOS Circuits and Technology Meeting 2000, 2000)
A down-conversion I/Q-mixer for a W-CDMA zero-IF receiver implemented in a 75 GHz ft bipolar SiGe technology is reported. Including I/Q-generation and biasing, it consumes a supply current of 18 mA from a 2.7 V supply. A voltage gain of 10.2 dB and an IIP3 of 8 dBm have been achieved. Using frequency division to derive the I- and Q-phases for the local oscillator signals results in LO-RF leakage lower than -68 dBm and an IIP2 better than 56 dBm. DC offsets at the I and Q mixer baseband outputs are typically below 5 mV
elib2cris::1512001600,pretl2000a
Keywords: Mixer; UMTS

A SiGe Bipolar WCDMA Power Amplifier with 52% PAE at 3.3 V - Kitlinski, Krzysztof; Donig, Günther; Bakalski, Winfried; Kapfelsperger, Boris; Weigel, Robert (International Journal of Electronics and Telecommunications, 2004)
elib2cris::1512001600,kitlinski2004

A Signal Source Chip at 140 GHz and 160 GHz for Radar Applications in a SiGe Bipolar Technology - Völkel, Matthias; Thouabtia, Mohamed; Breun, Sascha; Aufinger, Klaus; Weigel, Robert; Hagelauer, Amelie Marietta (MWSCAS, 2019)
In this paper, a monolithic signal source chip at 140 GHz and 160 GHz including two VCOs, a dynamic divider and a static divider chain is presented. Two signal sources with these high fundamental frequencies are realized. All components have been designed using a 0.13μm 250 GHz fT SiGe BiCMOS technology. The whole integrated circuit has a size of 930μm x 600μm including bondpads and consumes 210mA from a 3.3V and 130mA from a 1.8V supply. The oscillators cover a frequency range from 119.3–147.7 GHz and 154.2–164 GHz, which results in a tuning range of 28.4 GHz and 9.8 GHz. A output power of -0.9/3.6dBm with a best case phase noise of -111.2/-108 dBc/Hz at 1MHz offset, measured at the divider output for PLL stabilization is achieved.<br
Keywords: FMCW; industrial radar; millimeter-wave; oscillator; signal source; VCO.

A Silicon Integrated Microwave Vector Network Analyzer for Biomedical Sensor Read-Out Applications - Nehring, Johannes; Nasr, Ismail; Borutta, Karl; Weigel, Robert; Kissinger, Dietmar (IEEE MTT-S International Microwave Symposium (IMS), 2014)
This paper proposes an integrated reflectometer for biomedical sensor read-out applications using a low-cost silicon- germanium technology. The heterodyne reflectometer consists of two integrated cross-coupled oscillators, a set of two directional couplers as well as Gilbert-Cell downconversion mixers. A dual phase-locked-loop architecture guarantees the phase lock of both on-chip signal sources to an external reference oscillator. An OSM-calibration was applied to the reflectometer and measure- ments of the complex reflection coefficient of an arbitrary device under test (DUT) showed excellent agreement with the results of a commercial vector network analyzer. As a proof of concept for sensor read-out, five solutions with different mixture ratios were characterized with a dielectric probe connected to the reflectometer.
elib2cris::1512001600,nehring2014

A Simple and Low-Cost Technique to Measure the Magnetic Susceptibility of Ferrofluids - Thalmayer, Angelika; Xiao, Keyu; Lübke, Maximilian; Borin, Dmitry; Odenbach, Stefan; Unterweger, Harald; Helmreich, Klaus; Fischer, Georg (IEEE Sensors, 2023)

A Simple Low Jitter Wireless Triggering and Unidirectional Communication System - Depold, Andreas; Dorn, Christian; Weigel, Robert; Lurz, Fabian (2023 IEEE Topical Conference on Wireless Sensors and Sensor Networks, WiSNeT 2023, 2023)
This paper presents a simple, low-cost synchronization system based on a Sub-GHz of-the-shelf transceiver. It is intended for synchronization between a base station and mobile measurement system for search and rescue applications. Time critical scheduling information can be transmitted together with triggering pulses. Additionally, during off time bulk data can be transmitted. The system allows for triggering with a known latency and with a standard deviation below 200 ns.
Created from Fastlane, Scopus look-up
Keywords: triggering; wireless sensors; wireless synchronization

A simplified equivalent model for microwave characteristics of porosified LTCC - Talai, Armin; Steinhäußer, Frank; Bittner, Achim; Schmid, Ulrich; Weigel, Robert; Kölpin, Alexander (XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014)
High frequency materials show a manifold variety of complex permittivities for different applications. Recent research results demonstrated that porosification of Low Temperature Cofired Ceramics (LTCC) represents a new manufacturing technology, which enables local selective reduction of the relative permittivity. The permittivity gradients were measured and subsequently modeled to perform electromagnetic field simulations. The results of the complex CAD model are used, to create a simplified equivalent model, which is suitable for rapid RF circuit design on porosified LTCC. Since substrate properties vary between circuit components, the substrate-dependency on the lumped elements of the transmission line model is considered. It is shown that the introduced porosification gradient can be considered for network-based SPICE simulations on porous LTCC.
elib2cris::1512001600,talai2014b

A Simulation Model for Galileo/GPS Receivers including the RF Front-End - Ehm, Henning; Schmid, Andreas; Neubauer, André; Günther, Christoph; Weigel, Robert (European Navigation Conference, 2005)
elib2cris::1512001600,ehm2005b
Keywords: Galileo; System Simulation

A Single Carrier Frequency Domain Equalization Prototype System - Huemer, Mario; Reinhardt, Steffen (Proceedings of the European Microwave Association, 2007)
In this paper we describe an SC/FDE (Single Carrier transmission with Frequency Domain Equalization) prototype system operating in the 2.4 GHz band. The system is based on an off-the-shelf 802.11b WLAN (Wireless Local Area Network) front-end module, on specially designed mixed signal boards for analog-to-digital (AD) and digital-to-analog (DA) conversion, and on a flexible DSP/FPGA solution for synchronization and baseband algorithm implementation. The prototype setup allows to transmit data over real RF (Radio Frequency) channels and to test the synchronization concepts as well as the equalizer algorithms under real conditions. We give a brief introduction to the SC/FDE theory, describe our prototype setup in detail, and finally present measurement results for different test scenarios.
elib2cris::1512001600,huemer2007

A Single-Chip 15-32 GHz Signal Source in SiGe Bipolar Technology - Nehring, Johannes; Nasr, Ismail; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (European Microwave Integrated Circuits Conference (EuMIC), 2013)
This paper presents a single-chip octave-bandwidth signal source covering a frequency band from 15GHz to 32GHz. The circuit was fabricated in a 0.35 μm SiGe bipolar technology with an ft/fmax = 170/250GHz. An array of four crosscoupled voltage controlled oscillators with subsequent frequency ranges is implemented. The oscillator cores only draw 13mA from a 3.3V supply. Another 13mA is drawn by following buffer stages. A 4-to-1 multiplexing amplifier acts as a combiner providing the octave-wide bandwidth at a single differential output. The output power was measured to be between -2.5 dBm and 0.7 dBm. The signal source provides a good phase noise performance of -105 dBc/Hz at 15GHz and -96.8 dBc/Hz at 30GHz at an offset of 100MHz from the carrier frequencies. The overall circuit consumes a total power of 205mW and occupies a chip area of 1128 μm x 1028 μm.
elib2cris::1512001600,nehring2013
Keywords: VCO; signal source; wideband; microwave; octave-wide bandwidth

A single-chip 75 GHz/0.35 μm SiGe BiCMOS W-CDMA homodyne transceiver for UMTS mobiles - Thomann, Wolfgang; Thomas, Volker; Hagelauer, Richard; Weigel, Robert (Radio Frequency Integrated Circuits (RFIC) Symposium, 2004)
A single-chip, fully-integrated 3G UMTS/W-CDMA transceiver has been implemented in a standard 75-GHz/0.35 μm SiGe BiCMOS process for use in FDD mobile terminals. The design comprises two integer-N/fractional-N synthesizers with fully integrated CMOS VCOs, on-chip tuning and PLL, a zero-IF receiver and a direct-conversion transmitter. The zero-IF receiver includes a differential-input, bipolar, low-noise amplifier (2nd LNA), a down-converter with CMOS Gilbert type mixers followed by a low-noise buffer amplifier, an analog active baseband filter of 5th-order with automatic on-chip filter calibration and interleaved with a programmable gain amplifier, and a programmable baseband output buffer. The direct-conversion transmitter includes a 4th-order analog active baseband filter, a bipolar direct modulation up-converter, and a variable gain RF amplifier with >80 dB gain control range, and a 3 dBm power amplifier driver. The transceiver is fully-programmable via two serial 3-wire-bus interfaces.. The device operates at 2.7-3.0 V supply and consumes 35 mA and 53-78 mA, in the receive mode and in the transmit mode, respectively. The transceiver is mounted in a small outline, 40-pin, leadless, 5.5×6.5 mm2 surface mount package and fully complies with ARIB W-CDMA and UMTS standards.
elib2cris::1512001600,thomann2004

A single-chip Si-bipolar 1.6 GHz VCO with integrated bias network - Zannoth, Markus; Fenk, Josef; Springer, Andreas; Weigel, Robert (IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, 1999)
A single-chip 2.7 V voltage-controlled oscillator (VCO) with integrated bias network has been implemented in a Si-bipolar process with a fT of 25 GHz. With an on-chip resonator consisting of vertically coupled inductors and varactor diodes an oscillation frequency of 1.56 GHz was measured. A careful design of the oscillator and the bias network was necessary to achieve a phase noise performance of -139 dBc/Hz at 4.7 MHz off carrier. The tuning sensitivity was 100 MHz/V, which is sufficient to compensate for production tolerances. The VCO can be used as a building block for single-chip transceivers in DECT- or GSM-systems
elib2cris::1512001600,zannoth1999

A Single-Chip Si-Bipolar 1.6-GHz VCO with Integrated-Bias Network - Zannoth, Markus; Fenk, Josef; Springer, Andreas; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2000)
A single-chip 2.7-V voltage-controlled oscillator (VCO) with an integrated-bias network has been implemented in an Si-bipolar process with an fT of 25 GHz. With an on-chip resonator consisting of vertically coupled inductors and varactor diodes, an oscillation frequency of 1.56 GHz was measured. A careful design of the oscillator and bias network was necessary to achieve a phase noise performance of -139 dBc/Hz at 4.7 h MHz off carrier. The tuning sensitivity was 100 MHz/V, which is sufficient to compensate for production tolerances. The VCO can be used as a building block for single-chip transceivers in digital European cordless telephone or global system for mobile communication systems.
elib2cris::1512001600,zennoth2000
Keywords: VCO; Si-Bipolar

A single chip SiGe receiver front-end at 77 GHz - Hartmann, Marcus; Wagner, Christoph; Seemann, Kay; Platz, Johannes; Jäger, Herbert; Weigel, Robert (Proceedings of the European Microwave Association, 2007)
elib2cris::1512001600,hartmann2007b

A Single-RF Architecture for Multiuser Massive MIMO Via Reflecting Surfaces - Bereyhi, Ali; Jamali, Vahid; Müller, Ralf; Tulino, Antonia M.; Fischer, Georg; Schober, Robert (ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, 2020)
In this work, we propose a new single-RF MIMO architecture which enjoys high scalability and energy-efficiency. The transmitter in this proposal consists of a single RF illuminator radiating towards a reflecting surface. Each element on the reflecting surface re-transmits its received signal after applying a phase-shift, such that a desired beamforming pattern is obtained. For this architecture, the problem of beamforming is interpreted as linear regression and a solution is derived via the method of least-squares. Using this formulation, a fast iterative algorithm for tuning of the reflecting surface is developed. Numerical results demonstrate that the proposed architecture is fully compatible with current designs of reflecting surfaces.
CRIS-Team Scopus Importer:2020-09-18
Keywords: least-squares; massive MIMO; reflecting surfaces; Single-RF transmitter

A Six-Port Interferometer Based Micrometer-Accuracy Displacement and Vibration Measurement Radar - Barbon, Francesco; Vinci, Gabor; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (International Microwave Symposium, 2012)
Displacement detection and vibration measure- ments are important requirements for automation and me- chanical stress diagnosis in diverse industrial environments. Laser interferometry is a widely used technique for these kinds of measurements since it features high-resolution, wide dynamic range and wide frequency response. Another advantage of the laser interferometry technique is contactless diagnosis/sensing which allows remote operations. However this technique is not suitable in harsh environments for instance with the presence of dust or fog which occur in several industrial production sites. In this paper a new contactless radar based vibration measurement technique is presented. It features an RF frontend based on a passive six- port interferometer working at 24 GHz. A dedicated signal processing unit is also presented. The proposed hardware allows to measure with a position accuracy of 0.5 µm.
elib2cris::1512001600,barbon2012a
Keywords: six-port; vibrometer; positioning; calibration; phase measurement; interferometer; radar

A Six-Port Radar System for Precise Distance Measurements and Vibration Monitoring in Industrial Environments - Vinci, Gabor; Linz, Sarah; Mann, Sebastian; Lindner, Stefan; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (Sensors and Measuring Systems; 17. ITG/GMA Symposium, 2014)
The Six-Port receiver has been subject of several investigations in the last years especially for radar applications in different areas, from accurate contactless vibration analysis, through automotive radar calibration to remote breath and heartbeat monitoring. The advantages of the Six-Port receiver such as excellent phase discrimination, trivial signal processing and low circuit complexity as well as cost, are the features that lead the radar industry to further development of this 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.
elib2cris::1512001600,vinci2014
Keywords: Six-Port; Radar; Vibration Monitoring; Industrial Environments; compact sensor

A Six-port Receiver Analog Front-End for Direct Conversion Reception in the K-Band - Kölpin, Alexander; Winter, Sebastian; Weigel, Robert (Proceedings of the European Microwave Association, 2005)
In modern radio communication systems high data rates are of great interest for home and business applications. Beside the use of novel techniques like MIMO the demand for bandwidth increases in order to deal with these requirements. Frequency allocation issues and technical aspects shift the carrier frequencies more and more toward microwave frequencies. With shrinking wavelengths and the high performance of today’s digital signal processing devices an alternative receiver architecture starts to compete with heterodyne and homodyne receiver concepts. In this paper the analog front-end of a so-called six-port receiver for the K-band is introduced. In difference to the heterodyne and homodyne concepts the conversion of the RF signal to baseband is done by additive superpositions of the local oscillator’s (LO) signal and the RF with different phase relations. The results are four output signals with different amplitudes generated by constructive and destructive superposition of the two input signals. By evaluating their powers the complex valued information of the sent RF signal can be recovered. The receiver’s hardware complexity is drastically reduced compared to other direct conversion concepts. Theoretical background, design process, practical tips for assembling and measurement results of the passive analog structure of a six-port receiver operating at 24GHz will be presented in this paper.
elib2cris::1512001600,koelpin2005a
Keywords: six port; direct conversion

A Sixport Receiver Architecture for 60-GHz OFDM Communication Systems - Winter, Sebastian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2008)

A Sixport Receiver's Analog Front-End for the K-Band Based on a Rapid-Prototyped PCB - Kölpin, Alexander; Winter, Sebastian; Eireiner, Thomas; Weigel, Robert (IEEE Mediterranean Electrotechnical Conference, 2006)
Within the scope of the research project presented in this paper an alternative architecture to mixing based receivers like hetero- or homodyne receivers is investigated: the sixport receiver. The theoretical aspects of the system concept are shown and the structure of the analog front-end is presented supported by measurement results. The analog front-end is based on a microwave circuit with a carrier frequency of 24 GHz and constructed as a PCB milled by a circuit board plotter.
elib2cris::1512001600,koelpin2006
Keywords: Six-Port; Frontend

A Six-Port Receiver's Analog Front-End of Reduced Size Based on a Multi-Layer Layout - Kölpin, Alexander; Winter, Sebastian; Weigel, Robert (IEEE/MTT-S International Microwave Symposium, 2007, 2007)
In this paper a compact front-end of a six-port receiver is presented based on a multi-layer circuit topology. For higher frequencies the six-port receiver architecture offers a good alternative to common receiver concepts. One drawback is the occupied size of the microwave couplers used in the analog front-end depending normally directly on the wave length and is opposed to an implementation of the passive six-port structure on a MMIC. With the results of the investigations presented in this paper a reduction in size of the six-port's transmission line structure of about 79% is achievable. The performance of the proposed multi-layer structure is compared to the common planar topology and shows only slight degradation.
elib2cris::1512001600,koelpin2007a

A Small and Lightweight Ultra-Low Power GSM Cell Tracker - Erhardt, Stefan; Weigel, Robert; Kölpin, Alexander (2019 IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2019)
In this publication a logger is introduced that is small and lightweight enough to be carried by bats. It tracks the GSM downlink spectrum, enabling coarse localization. The logger contains a Sub-GHz transceiver, a microcontroller and a DC/DC converter assembled on a flexible printed circuit board (PCB) that is directly mounted on a lithium coin cell battery. The total weight is approximately 2.1 g and the size is comparable to two stacked 1 Euro Cent coins after coating the logger with epoxy resin. A flexible nickel titanium wire antenna is used for receiving GSM signals and for transmitting in the European 868 MHz short-range devices (SRD) band. In a short-term field test the functionality was proven.

A Smart Jamming System for UMTS/WCDMA Cellular Phone Networks for Search and Rescue Applications - Zorn, Stefan; Gardill, Markus; Rose, Richard; Götz, Alexander; Weigel, Robert; Kölpin, Alexander (IEEE MTT-S International Microwave Symposium Digest (MTT), 2012, 2012)
Recent statistics show an increase in environmental disasters, a fact which is also perceivable to the public as reports of avalanches, earthquakes and landslides mount in media coverage. This paper introduces one part of the I-LOV project, endorsed by the German Federal Ministry of Education and Research. In this project partners from relief organizations, universities and industry investigate enhancements to disaster handling and victim rescue. One possible option is to take advantage of the fact, that a lot of people own a mobile phone today. To locate a person by his or her mobile phone requires to take over the phone by an own Base Transceiver Station (BTS). Jamming all other networks is one option to achieve that. This paper will introduce a new Field Programmable Gate Array (FPGA) based jamming system which disturbs only the absolute necessary parts of the WCDMA spectrum but reliably cuts all connections between mobile stations (MS) and existing BTS. The whole system including the signal generator and the front end will be discussed. Also measurement results will be shown.
elib2cris::1512001600,zorn2012
Keywords: GSM; Jamming; Mobile communication; Mobile handsets; Multiaccess communication; Radio frequency; Spread spectrum communication; FPGA

A Snap-Shot Positioning Approach for a High Integrated GPS/Galileo chipset - Kaniuth, Roland; Eissfeller, Bernd; Lemke, Norbert; Heinrichs, Günther; Winkel, Jón; Ehm, Henning; Weigel, Robert; Schmid, Andreas; Neubauer, André; Nagel, Peter (Proc. ION-GNSS, 2005)
elib2cris::1512001600,kaniuth2005c

ASPEC: Adaptive Spectral Perceptual Entropy Coding of High Quality Music Signals - Brandenburg, Karlheinz; Herre, Jürgen; Johnston, J D; Mahieux, Y; Schroeder, E F (90th AES Convention, 1991)
ASPEC is the joint proposal of AT&T Bell Laboratories, Thomson Consumer Electronics, Fraunhofer Society and CNET for the audio coding standard which is drafted by the ISO/IEC JTC1/SC2/WG11 audio experts group (MPEG-Audio). It combines high coding efficiency with the flexibility needed to work in different applications, from 64 kbps per channel with FM quality to 128 kbps for CD quality. The algorithm is suitable for uses such as ISDN audio transmission, fixed and writable storage applications, and Digital Audio Broadcasting.
Vorträge und Veröffentlichungen auf Konferenzen_Gehörangepasste Datenreduktion

A Spectrum Sensing Network for Cognitive PMSE Systems - Brendel, Johannes; Rieß, Steffen; Stöckle, Andreas; Rummel, Rafael; Rose, Richard; Fischer, Georg (7th Workshop on Software Radios (WSR), 2012)
This paper is about a Spectrum Sensing Network (SSN) which generates an accurate radio environment map (e.g. power over frequency, time, and location) from a given application area. It is intended to be used in combination with cognitive Program Making and Special Events (PMSE) devices (e.g. wireless microphones). It consists of a distributed network of multiple scanning radio receivers and a central data management and storage unit. The parts of the SSN are presented in detail and the advantages and the use cases of such a sensing network structure are outlined.
elib2cris::1512001600,brendel2012

A Spectrum Sensing Network for Cognitive PMSE Systems - Brendel, Johannes; Rieß, Steffen; Stöckle, Andreas; Rummel, Rafael; Fischer, Georg (Frequenz, 2012)
This article is about a Spectrum Sensing Network (SSN) which generates an accurate radio environment map (e.g. power over frequency, time, and location) from a given application area. It is intended to be used in combination with cognitive Program Making and Special Events (PMSE) devices (e.g. wireless microphones) to improve their operation reliability. The SSN consists of a distributed network of multiple scanning radio receivers and a central data management and storage unit. The parts of the SSN are presented in detail and the advantages and use cases of such a sensing network structure will be outlined.
elib2cris::1512001600,brendel2012b
Keywords: PMSE; cognitive radio; spectrum sensing network; scanning receiver

Assessing the Severity of Congestive Heart Failure by New Parameters of Circadian variation - Rockstroh, Christian; Kirchner, Jens; Krämer, Thomas; Hensel, Bernhard (Biomedizinische Technik. Biomedical engineering, vol. 56, iss. s1, 2011)
Introduction Circadian variation reflects the overall activity of a patient and thus promises to particularly indicate changes in cardiac function in patients with congestive heart failure (CHF). A model that allows reconstructing parameters of the day-night rhythm with a minimal set of presuppositions is provided by the non-stationary Langevin equation. The clinical applicability of these parameters was evaluated. Methods We analyzed 24-h RR-interval time series, which are publicly available at PhysioNet.org. The study populations included patients with normal sinus rhythm as well as with mild to medium CHF. From the Langevin model, parameters were derived that correspond to heart rates typical for day and night phases, respectively, to the difference between these values and to sleeping duration. Additionally, standard parameters of heart rate variability in time domain were computed, which serve as gold standard for cardiologic time series analysis. In order to estimate the impact of measurement artifacts on the method, analysis was performed both on raw and filtered signals. Results The Langevin parameters discriminate between patients with normal sinus rhythm and those suffering from mild CHF as well as the standard HRV parameters. When applied to patient groups with mild and medium CHF, respectively, the new approach performs even better than the gold standard. Hence, both the onset and worsening of heart failure are indicated by the new parameters. In contrast to the standard HRV parameters, these results remain unaltered if the raw instead of the filtered signal is used. These results indicate that the parameters from circadian variation are robust against measurement artifacts. Sensitivity to clinical cofounders is unlikely, due to tests with medium CHF patients from different databases showing no significant differences. Conclusion The Langevin approach to circadian variation provides robust markers for changes in cardiac condition, which are hence suitable for clinical use.

Assessment of the effects of scanning and reconstruction parameters on bone densitometry results for single energy quantitative CT (qCT) scans in a phantom study - Hofmann, Philipp; Lenhart, Björn; Sedlmair, Martin; Schmidt, Bernhardt; Flohr, Thomas; Mahnken, Andreas (European Congress of Radiology, 2016)
Keywords: Musculoskeletal spine; Bones; Computer applications; CT-Quantitative; CT; Absorptiometry / Bone densitometry; Computer Applications-Detection; diagnosis; Physics; Osteoporosis; Demineralisation-Bone

Assessment of Transmitter Initiated Wake-Up Radio Versus Pure Wake-Up Receiver Decoding - Hierold, Martin; Weigel, Robert; Kölpin, Alexander (IEEE Microwave and Wireless Components Letters, 2017)
Energy efficient data transmission is a crucial task in wireless sensor networks. Wake-up radio (WuR) communication offers big potential here, rendering pure asynchronous communication possible. Two different approaches of WuR communication are presented here and a dedicated hardware implementation is proposed. By assessing the performance concerning energy efficiency for both approaches, their impact on the number of payload data bits and the number of nodes in communication range is revealed. A decision guidance is provided based on the parameters of a specific application scenario.

A state-based power estimation methodology at system level for integrated RF front-ends - Glock, Stefan; Fischer, Georg; Weigel, Robert; Hasholzner, Ralf; Ußmüller, Thomas (Semiconductor Conference Dresden 2011, 2011)
This paper introduces an approach to model the power consumption of analog and mixed-signal systems at system level. The method is based on power state machines and is practically applied to a zero-IF receiver. The power state machines model the static power consumption of components with respect to their current state or state transition. The power consumption per state and state transition, respectively, is obtained from a low-level circuit simulation or from measurement. The concept of power state machines can be used for any analog component and enables the simulation of heterogeneous systems with the benefit of a fast simulation time.
elib2cris::1512001600,glock2011

A study on machine learning methods for accuracy improvement of in-body device localization - Dmitrieva, Daria; Anzai, Daisuke; Kirchner, Jens; Fischer, Georg; Wang, Jianqing (BIOEM The Joint Annual Meeting of the Bioelectromagnetics Society and the European Bioelectromagnetics Association, 2022)
Wireless devices for medical purposes play a promising role in implant body area networks. This study presented an artificial intelligence-based method to improve the localization of the wireless capsule endoscope during the liquid phantom experiment. The channel characteristics of signal at 400 MHz medical implant communication service (MICS) band were calculated based on the experimental data and used for conventional maximum likelihood estimation as well as to simulate the synthetic training data to introduce a possible solution for training data harvesting. The proposed method showed the root mean square localization error of 1.74 cm compared with 6.66 cm of the conventional method <
Keywords: Body Area networks; BAN; implant communication; MICS

A Study on Neural Network Method for In-body Implantable Device Localization - Dmitrieva, Daria; Anzai, Daisuke; Kirchner, Jens; Fischer, Georg; Wang, Jianqing (IEICE Society conference, 2022)
Keywords: WCE; localization; RSSI; implant; ML; phantom

A Study on Nonlinear Effect of Low-Frequency Modulated Radio Signals on Stimulus Response - Shinoda, Hiroki; Anzai, Daisuke; Kirchner, Jens; Fischer, Georg; Wang, Jianqing (IEICE Transactions on Communications, 2019)
Stimulus response caused by low-frequency electromagnetic exposure can be used to realize effective medical treatments. However, it is well known that the membrane potential of nerve cells exhibits nonlinearity, particularly in the case of modulated signals, it is important to analyze the nonlinear stimulation effect based on a nerve cell model. This paper adopts the Frankenhaeuser–Huxley (FH) model as the nerve cell model, and evaluates the stimulus response based on the FH model when nerve cells are exposed to low-frequency modulated radio signals such as On-Off Keying (OOK) modulation. This paper investigated the nonlinear effect of the stimulus intensity from the viewpoint of the spike frequency with different modulation parameter values including the induced amplitude and duty cycle. It was confirmed that action potential (AP) rate was higher with OOK-type radio signals than with unmodulated signals. <br
Keywords: Low-frequency stimulation; Frankenhaeuser-Huxley model; Nonlinear Response; On-Off keying modulation

A summary of the Stratix Report “Digitisation of Wireless Microphones” - Fischer, Georg (International Broadcast Convention (IBC) Conference, 2019)
Keywords: PMSE; Digitisation; spectrum; compression; source coding

A Supercapacitor Powered Radar Sensor Node for Lamination into Wind Energy Rotor Blades - Kurin, Thomas; Erhardt, Stefan; Weigel, Robert; Lurz, Fabian (2021 IEEE Radio & Wireless Week, 2021)
This paper presents a low power sensor node that is embedded into glass fiber composite material of rotor blades during production. The structural condition of the rotor blade is monitored by an integrated FMCW radar. The sensor can achieve a lifetime of 20+ years due to the longevity of a supercapacitor based energy supply. As the available power is low, special consideration must be given to energy saving and system up-time optimization. The concept was proven by embedding the sensor in epoxy resin and consecutively in test sheets produced like rotor blade materia
Keywords: Electronic circuits; Low-power electronics; Sensor node; Supercapacitors; Radar

A Survey on Analog-to-Digital Converter Performance with Respect to Ionizing Radiation - Müller, Steffen; Weigel, Robert; Kölpin, Alexander (European Conference on Radiation and Its Effects on Components and Systems (RADECS), 2017)

A Switchable, Passively Tuneable 28 GHz to 39 GHz Upconversion Link for a 5G Repeater using a Broadside Coupler and Analog Predistortion in a 130 nm BiCMOS Technology - Potschka, Julian; Zuber, Julian; Kolb, Katharina; Maiwald, Tim; Dietz, Marco; Aufinger, Klaus; Weigel, Robert; Hagelauer, Amelie (IEEE NEWCAS, 2020)

A Synchronized 35 GHz Divide-by-5 TSPC Flip-Flop Clock Divider in 22 nm FDSOI - Probst, Florian; Engelmann, Andre; Weigel, Robert (2023 Asia-Pacific Microwave Conference (APMC), 2023)

A Synchronous FPGA Design of a Bilateral Filter for Image Processing - Gabiger-Rose, Anna; Kube, Matthias; Weigel, Robert (35th Annual Conference of the IEEE Industrial Electronics Society, 2009)
elib2cris::1512001600,gabiger2009

Asynchronous Subthreshold CMOS Event Detector for Wireless BAN Sensor Nodes - Grimminger, Florian; Kowalczyk, G.; Unterassinger, H.; Schwarzmeier, Andre; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE BioWireleSS, 2013)
This work presents the implementation of an asynchronous event detector circuit by applying subthreshold standard cells. The presented circuit operates in an on-chip power management unit (PMU) of a wireless sensor node. Such an application demands an ultra-low power architecture for an increased overall lifetime of the sensor node. The asynchronous circuit architecture and its subthreshold logic implementation both significantly reduce the leakage power dissipation by factor three. The presented event detector is realized in a 130 nm CMOS process with regular transistors operating from a 200 mV supply voltage.
elib2cris::1512001600,grimminger2013
Keywords: Subthreshold; Asynchronouse; Event detector; Wireless sensor node

A System Architecture Case Study for Accurate Calibration of Memory Organizations under Process Variability - Papanikolaou, Antonis; Miranda, Miguel; Catthoor, Francky; Starzer, Florian; Lobmaier, F.; Huemer, Mario (Workshop on Application Specific Processors, 2005)
elib2cris::1512001600,papanikolaou2005
Keywords: Calibration; Memory

A Systematic Approach for Designing Beamsteering Algorithms for the Uplink of UMTS by Evolutionary Optimization Techniques - Schröter, Simon (IEEE Forum on Signal Processing for Radio Frequency Systems, 2013)
elib2cris::1512001600,schroeter2013

A System Concept for Online Calibration of Massive MIMO Transceiver Arrays for Communication and Localization - Gröschel, Patrick; Zarei, Shahram; Carlowitz, Christian; Lipka, Melanie; Sippel, Erik; Ali, Arslan; Weigel, Robert; Schober, Robert; Vossiek, Martin (IEEE Transactions on Microwave Theory and Techniques, 2017)
Massive multiple-input multiple-output (MIMO) techniques are being considered for the fifth generation (5G) mobile communication systems in order to deliver high multiplexing gain. However, hardware impairments like quadrature imbalance in mixers violate the requirement for channel reciprocity and may change, e.g., with temperature or while aging. In addition, advanced wireless localization techniques and the generation of predefined beam patterns require knowledge about all antenna phase center positions and the time and phase delay of all transmit and receive channels. Thus, an efficient online compensation method is needed that scales well for very large numbers of transceiver modules. We propose to extend the transmitter with a small measurement feature at the transmitter output based on one uncalibrated power detector per module as well as a single, external four-element backscatter array for the entire matrix. These enhancements facilitate a fast and efficient iterative calibration, which recognizes and mitigates all major error sources. Beside optimal communication throughput and energy efficiency, it thereby brings localization capabilities to mobile networks as an additional major benefit. For verification, a system of multiple cost-efficient 5.8-GHz massive MIMO transceivers with 150-MHz bandwidth and a backscatter array has been implemented. Measurement results demonstrate the capability of the proposed concept to efficiently compensate major error sources as well as its robustness.
elib2cris::1512001600,groeschel2017
Keywords: Backscatter transponder (BT); calibration; fifth generation (5G) mobile communication; massive multiple-input multiple-output (MIMO); wireless localization

A Tank Level Sensor Based on Six-Port Technique Comprising a quasi-TEM Waveguide - Mann, Sebastian; Lindner, Stefan; Linz, Sarah; Barbon, Francesco; Talai, Armin; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2014)
Robust tank level monitoring is an important issue in chemical and process industry and a challenging task if high accuracy has to be reached. The proposed sensor structure consists of a quasi-TEM mode waveguide on the one hand and an interferometric Six-Port receiver structure on the other hand. The waveguide structure itself in combination with the liquid to be monitored acts as a reflection phase shifter. By superposing the reflected and the transmitted electromagnetic wave within a passive structure, the relative phase between both signals can be accurately obtained by means of the Six-Port principle. Thus, a change of the liquid level is directly related to the relative phase shift monitored by the Six-Port interferometer. In contrast to antenna based tank level sensors, the hereby presented system concept makes use of a novel waveguide structure. therefore, it is not sensitive to multi-target scenarios and multipath propagation.
elib2cris::1512001600,mann2014
Keywords: Six-Port; Interferometer; tank; level monitoring; parallel plate waveguide; RADAR; microwave measurement

A Technology Independent Synthesis Approach for Integrated mmWave Coupled Line Circuits - Maiwald, Tim; Schrotz, Albert-Marcel; Kolb, Katharina; Potschka, Julian; Dietz, Marco; Hagelauer, Amelie Marietta; Weigel, Robert (IEEE Radio and Wireless Symposium, 2020)

A Thin-Film BST Varactor Model for Linear and Nonlinear Circuit Simulations for Mobile Communication Systems - Schmidt, Matthias; Lourandakis, Errikos; Weigel, Robert; Leidl, Anton; Seitz, Stefan (IEEE International Symposium on the Applications of Ferroelectrics, 2006)
A simple model of thin film BST varactors for the use in commercial circuit simulators is presented. The model implies the varactor's nonlinear capacitance as well as the frequency and voltage dependency of the losses. For the use of BST based components in mobile communication systems low tuning voltages are required. This leads unfortunately to high nonlinear distortion which is not acceptable. Another severe problem are the moderate to low quality factors and therefore high losses of the ferroelectric capacitors. The presented model allows estimating the losses and the distortion over a wide frequency range at every bias state with harmonic balance and envelope simulations. Further more it is now possible to predict the behavior of a designed circuit but also to deduce the requirements for BST varactors in order to achieve the demanded design goals. The model consists of a parallel circuit of equation based elements which represents the nonlinear capacitance and conductance. A constant series inductance and a constant resistance model the contacts. The required parameters can easily be extracted through measurements. To demonstrate the validity of the presented model a BST based SP2T switch at 1800 MHz was designed. An insertion loss of 1.4 dB at an isolation of 21 dB and a TOI of 35 dBm were achieved. The simulation and measurement results agree very good over a wide frequency range.
elib2cris::1512001600,schmidt2006
Keywords: BST; varactors; model; nonlinear; electrostriction

A time code division multiple access (TCDMA) system proposal for indoor wireless communications - Zhang, Zhongping; Seifert, Franz; Weigel, Robert (International Conference on Communication Technology, 1996)
Indoor environments for mobile radio communications provide special challenges due to the physical characteristics of the radio wave propagation. A hybrid access scheme (combining the advantages of both TDMA and wideband CDMA) called time code division multiple access (TCDMA) is proposed and investigated for indoor wireless communications. The indoor radio channel is modeled in terms of channel impulse responses by taking into account various indoor measurement results. Various simulation methods are used to reduce the computational complexity and to ensure the result accuracy. The simulation results of the system performance reveal the capability and the capacity of TCDMA in a typical indoor cell modeled as a multipath fading radio channel
elib2cris::1512001600,zhang1996
Keywords: hybrid; TCDMA; fading; channel; radio; multipath

A Time Difference of Arrival System Architecture for GSM Mobile Phone Localization in Search and Rescue Scenarios - Götz, Alexander; Zorn, Stefan; Rose, Richard; Fischer, Georg; Weigel, Robert (Workshop on Positioning, Navigation and Communication (WPNC), 2011)
In this work, a novel architecture of a time difference of arrival based localization system for GSM mobile phones is proposed. The system is well-suited for search and rescue scenarios and comprises receiving stations for GSM signals, a dedicated GSM base station and a radio frequency jamming system for GSM and UMTS signals. The system may be operated in the E-GSM 900 band providing high penetration of the covering debris material and a sufficient overall bandwidth for the time difference of arrival measurements. In this case, the best attainable accuracy of localization is shown to be in the scale of 5 m. The components of the system are described in more detail and possible implementations are proposed. The system may also be applied for the localization of UMTS mobile phones making use of the integrated GSM functionality. The proposed system represents a novel approach for time difference of arrival based localization of mobile phones in search and rescue scenarios.
elib2cris::1512001600,goetz2011
Keywords: GSM; Localization; TDOA

A Tone Mapping Algorithm Suited for Analog-Signal Real-Time Image Processing - Shi, Lan; Hadlich, David; Söll, Christopher; Ußmüller, Thomas; Weigel, Robert (12th International Conference on PhD Research in Microelectronics and Electronics (PRIME), 2016)
This work presents a Tone Mapping Operator (TMO) which adjusts the High Dynamic Range (HDR) of image sensor data to the limited dynamic range of conventional displays with analog signal processing. It is based on Photographic Tone Reproduction (PTR) and suitable for analog circuit design in a CMOS image sensor in order to reduce the hardware cost and operation time for real-time image processing. For this reason, the characteristic advantage and calculation limitation of analog technology are considered in the TMO algorithm proposal. Furthermore, the appropriate modelling is built and simulated in Verilog-A. The function of the algorithm is feasible for analog processing. The frequency of the analog TMO is upper 52MHz while it consumes 55mW. The simulation results of test images are compared with the digital global TMO and the proposed analog TMO provides a reasonable similar dynamic range compression.
elib2cris::1512001600,shi2016
Keywords: Image Processing; Tone Mapping; CMOS Image Sensor; Analog Circuit; GRK 1773

A Tunable and Reduced Size Power Divider Using Ferroelectric Thin-Film Varactors - Lourandakis, Errikos; Schmidt, Matthias; Leidl, Anton; Seitz, Stefan; Weigel, Robert (International Microwave Symposium (IMS), 2008)
elib2cris::1512001600,lourandakis2008a

A Tuneable Fully Single-Ended 39GHz to 28GHz Gilbert Micromixer for 5G Using Analog Predistortion in a 130nm BiCMOS Technology - Potschka, Julian; Dietz, Marco; Kolb, Katharina; Maiwald, Tim; Ferling, Dieter; Hagelauer, Amelie Marietta; Weigel, Robert (IEEE Radio and Wireless Symposium, RWS, 2020)
In this paper an adjustable-resonance down-conversion Gilbert Micromixer is proposed and investigated. For the circuit realization a 130nm BiCMOS process technology is used. The Micromixer is designed for single-ended to single-ended operation. A differential to single-ended conversion at the output of the mixer is realized by using a tuneable reactive current mirror. The output power can be adjusted by adjusting the center-frequency of the reactive tunable load. In this way, the Micromixer features an almost linear tuning range for output power adjustment. Analog predistortion is used for linearity enhancement. The Micromixer is simulated, designed and measured. A S-parameter and an output power measurement shows the effect of resonance-tuning and output power adjustment. The mixer yields a broadband low-Q matching network and a simulated power conversion gain of -1dB for maximum power adjustment at 28GHz as well as a measured power consumption of 69.3mW.
CRIS-Team Scopus Importer:2020-04-24
Keywords: 5G; Gilbert-Micromixer; Mixer; Reactive-Current-Combining; Tuneable-Mixer

Aufbau eines Sechtor-Empfängers als innovative Alternative zu mischerbasierten Konzepten für das K-Band - Kölpin, Alexander; Winter, Sebastian; Eireiner, Thomas (2005)
elib2cris::1512001600,koelpin2005c

Aufbau und Analyse eines verteilten Sensornetzes zur Erhebung einer Spektrumsauslastungskarte für kognitive Funksysteme“ - Brendel, Johannes (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2016)

Auf dem Weg zum intelligenten Kabel - Ehlenz, Tobias; Lenz, Philipp; Fischer, Georg; Wittmann, Armin (ETZ, Elektrotechnik und Automation, 2019)
Gegenstände unserer Umwelt werden zunehmend „intelligent“ und koordinieren sich untereinander. Fabrikationsanlagen sagen vorher, wann sie ausfallen. Autos optimieren gemeinsam den Verkehrsfluss. Smartphones überwachen die Gesundheit ihrer Besitzer. Für die teilweise kritischen Verbindungen, die durch Strom- oder Datenleitungen realisiert werden, gilt dies bis dato noch nicht. Die forensischen Betrachtungen von Kabeln und Leitungen im Kabellabor der Hochschule Trier ermöglichen es, dass dies nun auch für Leitungen in greifbare Nähe rückt. <br

A UHF RFID-Reader with Custom-Command Functionality for RFID-S Applications - Hofmann, Andreas; Brenk, Daniel; Boehme, Andreas; Cilek, Fatih; Weigel, Robert (IEEE RFID, 2010)
elib2cris::1512001600,hofmann2010

A Universal Method for the Design and Synthesis of Wideband Directional Couplers using Non-Uniform Coupled Transmission Lines - Nehring, Johannes; Hofmann, Maximilian; Münker, Christian; Weigel, Robert; Fischer, Georg; Kissinger, Dietmar (IEEE European Microwave Conference, 2012)
In this paper a complete procedure for the design, synthesis and construction of wideband directional couplers is presented. Cascading multiple quarter-wavelength line segments leads to an increase of coupling bandwidth up to 180% but also results in discontinuities of geometry and thus in strong reflec- tions. Furthermore, the isolation is diminished. To avoid these effects a design technique for the generation of continous, non-uniform geometries is analyzed and implemented. Two methods for the coupler synthesis are proposed and compared. One is an approximational approach and uses two sets of equations. The other uses accurate 2D field simulation of the propagating modes and is universally applicable to any kind of coupled transmission lines. The completely synthesized couplers are simulated in CST Microwave Studio and achieve very good results for coupling, isolation and return loss. A nominal -10dB wideband coupler at a center frequency of 15GHz and a nominal bandwidth of 164% is built in a multilayer stackup. Good agreement between measurement and simulation results is observed.
elib2cris::1512001600,nehring2012
Keywords: wideband directional coupler; wideband; coupler; non-uniform

Ausarbeitung eines Praktikums zur Vorlesung Architekturen der Digitalen Signalverarbeitung, VHDL Programmierung, Simulation und Inbetriebnahme - Glaser, Daniel; Kölpin, Alexander; Weigel, Robert (2006)
elib2cris::1512001600,glaser2006

Automated extraction of conducted emission relevant parameters in the case of a DC motor - Weigel, Robert; Leibinger, Árpád; Giese, M. (International Conference on Electromagnetics in Advanced Applications, 2011)
The analysis of the EMC (electromagnetic compatibility) behavior of products is needed nowadays in early project stages. Automation of EMC analysis in the case of systems with high complexity is crucial, because of the high number of parameters and extensive mechanisms of interaction. Systematic methods, however, can find the system parameters which dominate the behavior. Such procedures can be automated, thereby simultaneously speeding up the process and reducing the risk of errors. This paper gives a solution for the automated EMC analysis and optimization of devices using the simulator SABER. The emission was simulated according to the measurement standard CISPR 25. The parameters with the greatest influence on emission characteristics can be extracted from the parameters of system elements in a circuit simulation model by this proposed method based on global sensitivity analysis.
elib2cris::1512001600,weigel2011f
Keywords: DC motors; electromagnetic compatibility; CISPR 25; SABER; automated EMC analysis; circuit simulation model; device optimization; electromagnetic compatibility

Automated proximity sensing in small vertebrates: design of miniaturized sensor nodes and first field tests in bats - Ripperger, Simon; Josic, Darija; Hierold, Martin; Kölpin, Alexander; Weigel, Robert; Hartmann, Markus; Page, Rachel; Mayer, Frieder (Ecology and Evolution, 2016)
elib2cris::1512001600,ripperger2016

Automated Radar Data Labeling through Computer Vision - Gabsteiger, Jasmin; Maiwald, Timo; Wünsche, Simon; Weigel, Robert; Lurz, Fabian (Wamicon, 2023)
This paper presents the combination of an existing computer vision model with a highly integrated mmwave radar system for automated radar data labeling. A pre trained model for person presence detection is used in combination with a camera sensor to determine, whether a person is present or not. The binary prediction is used to label simultaneously measured radar data of the same scenery. The paper addresses the challenges of varying illumination conditions, camera and radar sensor aperture angles and data quality which are dominant influences at the labeling process. The system significantly decreases human effort by automating the labeling process. It is used to generate 10,000 data points, label them and train a neural network with 95.7% accuracy. Finally, a proof-of-concept, training, and evaluation of radarbased activity detection with automatically labeled data is presented. The proposed method can contribute in person presence detection under challenging light condition
Keywords: radar data labeling; computer vision

Automated Radar Data Labeling using MoveNet for Human Gesture Recognition - Maiwald, Timo; Gabsteiger, Jasmin; Weigel, Robert; Lurz, Fabian (2023 Asia-Pacific Microwave Conference (APMC), 2024)
Integrated radar sensors constitute an emerging technology used from smart home to autonomous driving applications. In combination with machine learning for radar data signal processing, they experience increasing popularity and are heavily investigated. These methods however need huge amounts of labeled training data to perform well in realistic scenarios, which is time consuming and cost intensive. To increase data acquisition speed, this paper presents a system using a fast computer vision model for automated radar data labeling. It is capable of generating 10 labeled radar data frames per second. To demonstrate the abilities it is used for human gesture recognition.<br
Keywords: gesture recognition; fmcw radar; computer vision; machine learning