SC/FDE combined with MIMO: An improved out of band power and performance via tamed frequency modulation - Buzid, Tufik; Huemer, Mario; Reinhardt, Steffen (Sarnoff Symposium, 2007)
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a power and bandwidth efficient broadband technique for the SISO and MIMO multipath channels. Finally we present simulation results.
elib2cris::1512001600,buzid2007

SC/FDE, OFDM and CDMA: A Simplified Approach - Buzid, Tufik; Reinhardt, Steffen; Huemer, Mario (European Conference on Wireless Technology, 2006)
We apply code division multiple access CDMA to single carrier transmission with frequency domain equalization SCFDE. We use the Fourier spreading codes at the transmitter with length equal the number of users and across the active users. It leads to the cancellation of the despreading process together with the inverse fast Fourier transformation (IFFT) at the receiver, and hence, we get the performance of SCFDE-CDMA with less complexity. Nevertheless, the system is transformed to OFDM. We obtain multicarrier OFDM, by applying IFFT across an arbitrary parallel SCFDE CDMA signals. The behaviour of the peak to average power ratio PAPR of the output signal reveals gaussian distribution, and thus, the PAPR is improved. It is therefore adequate to and effective in the nonlinear region of the power amplifier.
elib2cris::1512001600,buzid2006c

SC/FDE with Constant Phase Modulation combined with CDMA and MIMO - Buzid, Tufik; Reinhardt, Steffen; Huemer, Mario; Martoyo, I. (Advanced Communication Technology, 2006)
Single carrier transmission with a frequency domain equalization (SCFDE) is combined to MIMO system and extended to multiuser techniques CDMA. We also compare the overall system in terms of modulation format, such as constant phase modulations. The overall system features constant envelope transmit signals, which are immune to the non-linearity of the power amplifiers, a high spectral efficiency and a low complex equalization process at the receiver for multiuser enviroments. After a description of the concepts we show simulation results for SCFDE adapted to the MIMO-extended UMTS-TDD down link.
elib2cris::1512001600,buzid2006b

Schlussbericht Verbundprojekt: Lichtkonzept Historischer Stadtkern Rietberg‘ (KomLICHT) - Teilvorhaben: Erforschung der Akzeptanz, Effizienz, und Monitoring der Demonstrationsbeleuchtung, FKZ: 13N11335 - Gabel, Kristin; Werner, Daniel; Schwenzfeier-Hellkamp, Eva (2014)

SDR Implementation of an Adaptive Low-Latency IEEE 802.11p Transmitter System for Real-Time Wireless Applications - Kloc, Matej; Weigel, Robert; Kölpin, Alexander (IEEE Radio and Wireless Symposium (RWS), 2017)
elib2cris::1512001600,kloc2017

SDR OFDM Waveform Design for a UGV/UAV Communication Scenario - Blümm, Christian; Heller, Christoph; Weigel, Robert (SDR-WinnComm Europe Conference, 2011)
In the course of a national research project, EADS Innovation Works has developed a waveform on a self-designed hybrid Software Defined Radio (SDR) platform, consisting of an FPGA (Xilinx Virtex 5) and a GPP (Intel Atom). The waveform realizes a video link between an Unmanned Ground Vehicle (UGV) and its Ground Control Station (GCS). This link is established indirectly with an Unmanned Aerial Vehicle (UAV) acting as a relay, in order to enable non-line-of-sight (NLOS) communication and to increase the communication range. Additionally, a direct video link from the UAV to the GCS is set up simultaneously as well as multiple low data rate control channels between the individual link partners. To cope with diverse operation areas, accompanied by a heterogeneous set of requirements, the waveform must offer outstanding adaptability and flexibility to maximize data rates in each scenario, while maintaining link robustness. The developed waveform is based on OFDM with freely customizable modulation parameters. Time Division Multiple Access (TDMA) is implemented on medium access layer to switch between the different users in the scenario (UGV, UAV, GCS). In this article, we give an overview of the waveform, its implementation on a hybrid platform and its validation for the intended field of application.
elib2cris::1512001600,bluemm2011a

SDR-Proved Adaptive OFDM Guard Interval Scheme for Rapidly Varying Time-Dispersive Vehicular Broadcast Channels - Franchi, Norman; Kloc, Matej; Weigel, Robert (6th IEEE International Symposium on Wireless Vehicular Communications (WiVeC), 2014)
Driven by the results of existing field measurements for the characterization of vehicular radio channels, particularly vehicle-to-vehicle (V2V) channels, which showed that the effective range of possible maximum delay spreads is extremely wide (ranging from a few ns up to several μs), the strategic choice of Orthogonal Frequency Division Multiplexing (OFDM) with fixed guard interval (GI) duration shall be reconsidered at that point. Here, the major claims, both to optimize the data throughput at good channel conditions and to enable a reliable transmission of safety critical information at harsh environmental conditions, must be taken into account. Thus, in this paper, an adaptive guard interval (AGI) length scheme in context of vehicular ad hoc broadcast communication networks with rapidly time-varying channel conditions is proposed. The approach enables an OFDM symbol-based GI estimation without the prior knowledge of the GI length used in the transmitted symbol. By this means different GI lengths can be detected even within a frame. The suggested approach could be used to improve actual and upcoming physical layer (PHY) specifications, e.g. of Std. IEEE 802.11p. For a physically realistic evaluation of the proposed scheme, a fully IEEE 802.11p standard-compliant and reconfigurable softwaredefined radio (SDR) transmitter with symbol-based adaptable GI processing but fixed symbol duration is presented.
elib2cris::1512001600,franchi2014

Second Generation ISO/MPEG-Audio Layer III Coding - Herre, Jürgen; Brandenburg, Karlheinz; Grill, Bernhard; Eberlein, Ernst (98th AES Convention, 1995)
Vorträge und Veröffentlichungen auf Konferenzen_Gehörangepasste Datenreduktion

Second order intermodulation in direct conversion receivers - problems and solutions - Dufrene, Krzysztof (2012)
elib2cris::1512001600,krzysztof2012

Second order intermodulation in direct coversion receivers - problems and solutions - Dufrene, Krzysztof (EEEfCOM Workshop, 2005)
elib2cris::1512001600,dufrene2005

Sectoral Horn and Patch Array Antenna Design for a 76-81 GHz High-Resolution Tomographic Radar - Rahamtulla, Wafa Pathan; Och, Andreas; Hoelzl, Patrick; Schuster, Stefan; Pathuri-Bhuvana, Venkata; Weigel, Robert (2020 IEEE RADAR CONFERENCE (RADARCONF20), 2020)
CRIS-Team WoS Importer:2021-02-26

Securing Massive MIMO Systems: Secrecy for Free with Low-Complexity Architectures - Bereyhi, Ali; Asaad, Saba; Müller, Ralf; Schaefer, Rafael F.; Fischer, Georg; Vincent Poor, H. (IEEE Transactions on Wireless Communications, 2021)
Passively overheard massive multiple-input multiple-output (MIMO) settings are capable of suppressing eavesdroppers via narrow beamforming towards legitimate receivers. This implies that secrecy is obtained almost for free in these settings. This study shows that this is a valid property for a large class of low-complexity massive MIMO transmitters. The investigations consider two dominant approaches for complexity reduction, namely antenna selection and hybrid analog-digital precoding. It is shown that using either approach, the information leakage per achievable sum-rate vanishes as the number of transmit antennas grows large. The results demonstrate that, as the transmit array size grows large, the normalized information leakage obtained by antenna selection and hybrid analog-digital precoding converges to zero double-logarithmically and logarithmically, respectively. The analytical results are confirmed for various benchmark architectures via numerical simulations.
CRIS-Team Scopus Importer:2021-04-23
Keywords: antenna selection; hybrid analog-digital precoding; massive MIMO systems; Physical layer security

Segmental Polynomial Approximation based Phase Error Correction for Precise Near Field Displacement Measurements using Six-Port Microwave Interferometers - Will, Christoph; Linz, Sarah; Mann, Sebastian; Lurz, Fabian; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2017)
Six-Port microwave interferometers are a lowcost as well as low-power type of radar sensor with a high phase accuracy, which can be used for precise displacement measurements. Near field effects strongly influence the signal characteristics of a reflection of the electromagnetic wave near the antenna, especially if the target is low reflective. In this paper a calibration procedure based on phase error correction by segmental polynomial approximation is proposed that utilizes these effects. After validating the functionality of the calibration algorithm and its improvement by comparison to a comparable state-of-the-art procedure, two further near field measurements are presented. A cardboard as well as a plastic plate are used as low reflecting targets to show the applicability of the proposed calibration procedure for diverse measurement scenario
elib2cris::1512001600,will2017

Segmentation of Radar-Recorded Heart Sound Signals Using Bidirectional LSTM Networks - Shi, Kilin; Schellenberger, Sven; Weber, Leon; Wiedemann, Philipp; Michler, Fabian; Steigleder, Tobias; Malessa, Anke; Lurz, Fabian; Ostgathe, Christoph; Weigel, Robert; Kölpin, Alexander (41st IEEE International Engineering in Medicine and Biology Conference, 2019)
Sounds caused by the action of the heart reflect both its health as well as deficiencies and are examined by physicians since antiquity. Pathologies of the valves, e.g. insufficiencies and stenosis, cardiac effusion, arrhythmia, inflammation of the surrounding tissue and other diagnosis can be reached by experienced physicians. However, practice is needed to assess the findings correctly. Furthermore, stethoscopes do not allow for long-term monitoring of a patient. Recently, radar technology has shown the ability to perform continuous touchless and thereby burden-free heart sound measurements. In order to perform automated classification of the signals, the first and most important step is to segment the heart sounds into their physiological phases. This paper examines the use of different Long Short-Term Memory (LSTM) architectures for this purpose based on a large dataset of radar-recorded heart sounds gathered from 30 different test persons in a clinical study. The best-performing network, a bidirectional LSTM, achieves a sample-wise accuracy of 93.4% and a F1 score for the first heart sound of 95.8%.<br
Keywords: Heart; Electrocardiography; Radar; Logic gates; Medical services; Radar antennas; Pathology

S-EHRFEM - Substrate Extraction using Highly Reduced FEM-meshes for Transient SPICE-simulation with Iterative Linear Solvers - Schade, Alexander; Klotz, Frank; Jahn, Stefan; Weigel, Robert (EMC Europe 2019 - 2019 International Symposium on Electromagnetic Compatibility, 2019)
The nouveau S-EHRFEM approach to substrate extraction is based on a mathematical technique which strongly reduces the FEM-discretized Laplace equation in three dimensions. It reduces the nets by almost two orders of magnitude and the resistors by roughly one order of magnitude at an error bound < 10%. This translates into over an order of magnitude speedup of a transient circuit simulation using GMRES. The resulting model is reciprocal, reference-independent, charge-conserving and, under some weak assumptions, passive. This guarantees simulation stability and accuracy.
CRIS-Team Scopus Importer:2019-11-12
Keywords: fast-multipole BEM co-simulation; FEM co-simulation; GMRES; iterative linear solver; parasitic extraction; substrate extraction

Selbstteststrategien für Mikrowellen-Interferometrie zur hoch-genauen industriellen Abstandsmessung - Kölpin, Alexander; Mann, Sebastian; Lindner, Stefan; Linz, Sarah; Barbon, Francesco; Weigel, Robert (Testmethoden und Zuverlässigkeit von Schaltungen und Systemen (TuZ), 2014)
elib2cris::1512001600,koelpin2014

Selfadjusting SAW IF Channel Filtering For Mobile Communication Systems - Rheinfelder, Clemens; Scholl, Gerd; Weigel, Robert; Russer, Peter (8th European Frequency and Time Forum, 1994)
elib2cris::1512001600,rheinfelder1994

Self-powered Multiparameter Health Sensor - Tobola, Andreas; Leutheuser, Heike; Pollak, M; Spies, Peter; Hofmann, Christian; Weigand, Christian; Eskofier, Björn; Fischer, Georg (IEEE Journal of Biomedical and Health Informatics, 2018)

Selftest by μC to detect faulty capacitors - Can, Yavuz; Rantisi, Mohammed; Sattler, Sebastian (Scientific Cooperations Publications, 2013)
The presented work concerns the concept of validating measurements of simple analog filter  wirings in automotive electronic control units (ECU). Therefore, open or faulty capacitors should be detected. An input signal is fed to the filter circuit by means of the microcontroller TC1797, and the filter output signal for determining the functionality of the filter is received by the same microcontroller.
Keywords: Verification; µC 1797; ECU; signal theory; filter analysis

Selftest Strategies for Microwave Interferometry for High-Precision Industrial Distance Measurements - Kölpin, Alexander; Linz, Sarah; Barbon, Francesco; Lindner, Stefan; Mann, Sebastian; Lurz, Fabian; Weigel, Robert (20th International Conference on Microwaves, Radar, and Wireless Communications (MIKON), 2014)
Microwave interferometry is a tool for precisely measuring distances or vibrations of a target in industrial applications. Distance resolutions in the range of few micrometers and measurement value update rates of several tens of kilohertz are feasible. These parameters can only be achieved, if careful compensation of non-ideal effects is conducted. In this paper the basics of Six-Port based microwave interferometry as well as selftest techniques will be presented. Exemplarily, linearization of the operating point of the diode detectors and frequency estimation of the radar signal will be shown.
elib2cris::1512001600,koelpin2014a
Keywords: Six-Port; Selftest

Semi-deterministische und strahlenoptische Modellierung von Funkkanälen für zeitvariante Radar- und Kommunikationsanwendungen - Wahl, Rene (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2011)

Semi-Physical Behavioral Modeling of Radio Frequency Power Amplifiers for the Optimization of the Linearity-Efficiency Tradeoff - Glock, Stefan (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2014)

Sensitivity Analysis of Outphasing Elements for Hybrid Analogue Digital Beamforming and Single-RF MIMO - Gäde, Bernhard; Amon, Michael; Fischer, Georg; Müller, Ralf (KleinheubacherTagung 2018, 2018)

Sensor Data Acquisition with a 79-fJ/conversion-step 7.2-ENOB Successive Approximation ADC for Low-Power Wireless Applications - Brenk, Daniel; Essel, Jochen; Heidrich, Jürgen; Hofer, Günter; Holweg, Gerald; Weigel, Robert (IEEE Sensors, 2010)
A successive approximation (SAR) ADC is presented, whose components make use of effective ultra low-power techniques to enable wireless sensing with passive and semi-passive sensor nodes. Compared to prior publications new layout enhancements were applied to the integrated capacitive DAC array to gain less distortion caused by mismatch. In addition it is shown, that the digital circuit parts consume most of the available energy. Therefore digital near-threshold operation is proposed to minimize their consumption. The applicability of the ADC is demonstrated in an UHF RFID System. Within this system it is applied as core of a sensor interface integrated into a passive multi-standard RFID tag. The EPC protocol used for communication ensures the compatibility with standard UHF RFID readers while the sensor data is acquired using custom commands. The ADC consumes only 525 nA at 40kSps and 0.9 V supply voltage. Under these conditions an ENOB of 7.23 is reached and thus a FOM of 79 fJ/conversion-step.
elib2cris::1512001600,brenk2010

Sensor Enhanced Dual Frequency RSSI Distance Estimation for Low Weight Wireless Sensor Nodes - Duda, Niklas; Weigel, Robert; Kölpin, Alexander (2019 IEEE Asia-Pacific Microwave Conference (APMC) (APMC 2019), 2019)

Sensor Fusion by Bayesian Filtering for Seamless Pedestrian Navigation - Krach, Bernhard (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2009)

Sensor node design for animal tracking in resources limited wireless sensor networks - Duda, Niklas; Kölpin, Alexander (Workshop on Resource-efficient Localization in Wireless Sensor Networks, 2017)

Sensor Resistance Based Sensitivity Temperature Drift Tracking of Integrated 3D Hall Sensors - Krause, Dennis; Stahl-Offergeld, Markus; Sand, Markus; Kohlbrenner, Christian; Weigel, Robert (Proceedings of IEEE Sensors, 2023)
The magnetic sensitivity of voltage controlled Hall sensors changes up to ± 40% in the temperature range from -40°C to 125°C, resulting in large measurement errors. To track the temperature induced sensitivity variation, state of the art systems use additional temperature sensors and/or on-chip calibration coils. This paper presents a method to track the magnetic sensitivity temperature drift of a Hall sensor based on its own resistance. The proposed method results in a tracking accuracy of ± 6% for Bx, By and ± 3% for Bz in the temperature range from -40°C to 125°C. Providing a magnetic sensitivity to bias current transfer function further enhances the tracking accuracy to ≤ 1%. It requires no additional integrated coils or temperature sensors.
CRIS-Team Scopus Importer:2023-12-22
Keywords: Hall sensor; sensitivity tracking; temperature drift

Sensors and Wireless Data Distribution in Agriculture - Zimmermann, Lars (TGGS Multidisciplinary Seminar, 2012)
elib2cris::1512001600,zimmermann2012b

Sensor Selection for Classification of Physical Activity in Long-Term Wearable Devices - Kirchner, Jens; Faghih-Naini, Samira; Bisgin, Pinar; Fischer, Georg (2018 IEEE SENSORS, 2018)
Classification of physical activity based on the kNN algorithm is assessed with different combinations of sensors (from accelerometer, gyroscope, barometer) with respect to classification accuracy, power consumption and computation time. For that purpose, a wearable sensor platform is proposed and a study with 20 subjects is conducted. The combination of accelerometer and barometer is found to provide the best trade-off for the three criteria: It provides an F1 score of 94.96 ± 1.73 %, while computation time and power consumption are reduced by 45 % and 88 %, respectively, compared to the full sensor set. <br
CRIS-Team WoS Importer:2019-06-18
Keywords: Activity classification; wearable devices; sensors; accelerometer; gyroscope; barometer; knn; machine learning; power consumption; computation time; F1 score; sensitivity; precision

Short Course "MPEG-4 Audio" - Brandenburg, Karlheinz; Grill, Bernhard; Herre, Jürgen; Väänänen, R (IEEE International Symposium on Circuits and Systems, 2000)
Eingeladene Vorträge auf Konferenzen etc.

Short Course on Introduction to Third Generation Wideband CDMA and Their Impact on SAW Technology - Weigel, Robert; Ruppel, Clemens; Eichinger, Ludwig (IEEE International Ultrasonics Symposium, 2000)
elib2cris::1512001600,weigel2000c

Short Course on introduction to Third Generation Wideband CDMA Systems Like UMTS - Weigel, Robert; Springer, Andreas; Pimingsdorfer, Dieter (IEEE International Zurich Seminar on Broadband Communications, 2000)
elib2cris::1512001600,weigel2000a

Short Multipath Mitigation Technique Using Feedforward Neural Networks - Götz, Alexander; Waldmann, Benjamin; Weigel, Robert (German Microwave Conference (Gemic), 2009)
In this paper a novel approach for mitigation of short multipath distortions is presented. The technique is applicable to FMCW-based distance measurement systems assuming distinctly separated targets. The effects of spectral distortion caused by short multipath propagation in conjunction with Fourier-based frequency analysis methods are mitigated. For this purpose the distorted spectrum is first analyzed and specific characteristics are calculated. A Feedforward Neural Network processes these characteristics and provides a correction frequency relative to the erroneously shifted maximum in order to estimate the true line-of-sight frequency. A comprehensive analysis was performed by means of a two tone test. Applicability to real world environments was investigated by means of a multi tone test using an IEEE 802.15.4a channel model.
elib2cris::1512001600,goetz2009a
Keywords: Cause effect analysis; Distance measurement; Feedforward neural networks; Frequency estimation; Neural networks

Shunt MEMS switch requirements for Tunable Matching Network at 1.9 GHz in composite substrates - Silva Cortes, Victor Arturo; Fischer, Georg (German Microwave Conference (GeMiC), 2015)
A theoretical approach for the specification of shunt MEMS switches suitable for Tunable Matching Networks (TMN) at 1.9GHz is presented. DC-contact fixed-fixed beam MEMS switches designed with series metal-insulator-metal (MIM) capacitors at the grounding plane of a CPW transmission line provide the basic design block for the TMN. In the down-state, the MEMS switch makes an ohmic contact with the transmission line, as consequence, the down-state capacitance of the switch is dominated by the MIM capacitors. The proper dimensioning of the MIM capacitors enables to directly increase the capacitance ratio of the switch in order to operate at frequencies below 10 GHz. Based on predefined CPW transmission line configurations on composite substrates, the optimization of the capacitance ratio of the MEMS switch can be directly related to the geometry of the CPW transmission line.
elib2cris::1512001600,silva2015
Keywords: RF MEMS

SiCer: Meeting the Challenges of Tomorrow's Complex Electronic Systems [From the Guest Editors' Desk] - Stehr, Uwe; Hagelauer, Amelie Marietta; Hein, Matthias A. (IEEE Microwave Magazine, 2019)
CRIS-Team Scopus Importer:2019-09-24

Sichere und interaktive Steuerung von Produktionsanlagen durch vernetzte Umfeldsensoren - Lenhard, Thilo; Kölpin, Alexander (MikroSystemTechnik Kongress (MST), 2015)
Im Rahmen der Initiative Industrie 4.0 ist eines der Hauptthemen das dynamische Reagieren von bislang unflexiblen Produktionseinrichtungen auf wechselnde Anforderungen und Umgebungseinflüsse. In Zusammenarbeit mit der Universität Erlangen-Nürnberg und den Industriepartnern Siemens CT und Schnaithmann GmbH entwickelt die InnoSenT GmbH ein cyber-physisches Sensorsystem, das alle Distanzinformationen liefert, um in Echtzeit eine Interaktion zwischen Mensch und Maschine oder zwischen mehreren Maschinen zu ermöglichen [1]. Basis des Sensorkonzeptes ist ein universeller interferometrischer Radarsensor mit konfigurierbarer Antenne und einer Messgenauigkeit im Sub-mm-Bereich. Die Arbeiten beinhalten die Entwicklung einer speziellen integrierten Schaltung (MMIC) und neuartiger Packaging-Konzepte.
elib2cris::1512001600,lenhard2015
Keywords: Radar; SAR

SiGe-based 77GHz Automotive Radar Systems - Kissinger, Dietmar (Workshop Radar, Communication and Measurement, 2009)
elib2cris::1512001600,kissinger2009b

SiGe Integrated Broadband Wireless Sensors for Biomedical Applications - Kirchner, Jens; Nehring, Johannes; Guarin Aristizabal, Gustavo Adolfo; Nasr, Ismail; Lämmle, Benjamin; Dietz, Marco; Weigel, Robert; Kissinger, Dietmar; Hagelauer, Amelie Marietta (9th Sin-German Joint Symposium on Opto- and Microelectronic Devices and Circuits (SODC2016), 2016)
elib2cris::1512001600,kirchner2016a

Si-Ge Power Amplifier for WCDMA Handheld Applications - Kitlinski, Krzysztof; Donig, Günther; Kapfelsperger, Boris; Weigel, Robert (15th International Conference on Microwaves, Radar and Wireless Communications (MIKON), 2004, 2004)
A monolithic radiofrequency power amplifier for WCDMA handheld applications has been fabricated in a 0.35 μm, 40 GHz fT, volume production Si-Ge bipolar technology. The process technology features a doped ground connection for on-chip devices to improve the overall performance. At 3.3 V supply voltage saturated output power of 29 dBm with a PAE of 50 % has been achieved; simultaneously P-1dB is 28 dBm at 1.95 GHz and the small signal gain is 32 dB.
elib2cris::1512001600,kitlinski2004a
Keywords: Ge-Si alloys; millimetre wave power amplifiers; mobile handsets; 0.35 micron; 1.95 GHz; handheld applications; Equivalent circuits; Frequency

Signal-aware direction-of-arrival estimation using attention mechanisms - Mack, Wolfgang; Wechsler, Julian; Habets, Emanuël (Computer Speech and Language, 2022)
The direction-of-arrival (DOA) of sound sources is an essential acoustic parameter used, e.g., for multi-channel speech enhancement or source tracking. Complex acoustic scenarios consisting of sources-of-interest, interfering sources, reverberation, and noise make the estimation of the DOAs corresponding to the sources-of-interest a challenging task. Recently proposed attention mechanisms allow DOA estimators to focus on the sources-of-interest and disregard interference and noise, i.e., they are signal-aware. The attention is typically obtained by a deep neural network (DNN) from a short-time Fourier transform (STFT) based representation of a single microphone signal. Subsequently, attention has been applied as binary or ratio weighting to STFT-based microphone signal representations to reduce the impact of frequency bins dominated by noise, interference, or reverberation. The impact of attention on DOA estimators and different training strategies for attention and DOA DNNs are not yet studied in depth. In this paper, we evaluate systems consisting of different DNNs and signal processing-based methods for DOA estimation when attention is applied. Additionally, we propose training strategies for attention-based DOA estimation optimized via a DOA objective, i.e., end-to-end. The evaluation of the proposed and the baseline systems is performed using data generated with simulated and measured room impulse responses of a uniform-linear microphone array under various acoustic conditions, like reverberation times, noise, and source array distances. The data contains a single source-of-interest, noise, and directional interference. The best-performing systems are also evaluated using measured data. Our experiments show that DNNs used for DOA estimation are biased to the spectral source characteristics and the spectral attention distribution used during training (e.g., spectrally flat/sparse). We also show that this bias in the DOA estimator can be avoided if signal-processing methods are used in combination with attention. Overall, DOA estimation using attention in combination with signal-processing methods exhibits a far lower computational complexity than a fully DNN-based system; however, it yields comparable results.
CRIS-Team Scopus Importer:2022-03-11
Keywords: Attention; Deep learning; Direction-of-arrival; Signal-dependent

Signal detection and cooperative sensing with sensor nodes with limited dynamic - Brendel, Johannes; Rieß, Steffen; Schröter, Simon; Weigel, Robert; Fischer, Georg (IEEE International Workshop on Cognitive Cellular Systems (CCS), 2014)
The paper investigates the performance of the energy detector in fading environments under the constraint, that each sensor has only a limited dynamic range. First, the effects which limit the dynamic of a sensor node are discussed before the influence on the energy detector is analyzed. Simulations are presented how cooperative spectrum sensing affects the detection probability and it is shown that a sensing network with limited dynamic can gain much more from cooperation compared to a sensor network with ideal sensor nodes.
elib2cris::1512001600,brendel2014a

Signal Processing for Low-Power and Low-Cost Radar Systems in Bicycle Safety Applications - Dorn, Christian; Kurin, Thomas; Erhardt, Stefan; Lurz, Fabian; Hagelauer, Amelie (2022 IEEE Topical Conference on Wireless Sensors and Sensor Networks, WiSNeT 2022, 2022)
In this publication a miniaturized low-power radar system is introduced that allows detection, tracking and measurement of motorized vehicles passing a bicycle rider. The main focus of this paper is to show a system that is responding with a situation adapted modulation to different measurement requirements while keeping power consumption and BOM cost to a minimum. This is achieved with using an integrated 60 GHz radar and a STM32 ultra-low-power microcontroller for the required signal processing.
CRIS-Team Scopus Importer:2022-04-15
Keywords: dsp; edge computing; FMCW; radar

Signal Processing Strategies for Six-Port Based Direction of Arrival Detector Systems - Barbon, Francesco; Vinci, Gabor; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (9th International Multi-Conference on Systems, Signals and Devices (SSD), 2012)
Direction of Arrival (DOA) detection for industrial positioning is a relevant topic. Several applications make use of the six-port technology to perform phase difference based DOA measurements. The six-port receiver offers high accuracy, robustness and a low cost solution. The ability of this device to precisely measure a phase difference (hence a DOA angle) implies a correct acquisition of the signals delivered from the six-port detector as well as a correct digital signal processing. In this paper a dedicated acquisition platform for the six- port DOA detector is presented. Moreover, different software strategies to compute the DOA angle have been evaluated for an FPGA. Different types of algorithms have been implemented and compared using accuracy and throughput as references.
elib2cris::1512001600,barbon2012
Keywords: Direction-of-Arrival; Six-Port; Angle Measurement

Signal Transmission with Intra-Body and Inter-Body Communications - Ahmed, Doaa; Kirchner, Jens; Fischer, Georg (13th EAI International Conference on Body Area Networks, 2020)
Keywords: BAC; Body Area Communications; HBC; Human Body Communications; BAN; Body Area Network

Signal Transmission with Intra-body and Inter-body Communications (Simulation-based Models) - Ahmed, Doaa; Kirchner, Jens; Fischer, Georg (13th EAI International Conference on Body Area Networks (BODYNETS 2018), 2019)
In this paper, we investigate two types of data transmission in human body communication (HBC) with galvanic coupling: Intra-body communication along a human arm and inter-body communication between two arms in touch. For the former, the effect of bending the arm is investigated, too. The arms were modeled as five-layers concentric cylinders of different types of tissue. For simulation, the finite element method (FEM) COMSOL Multiphysics5.3a software was used. The influence of different HBC key parameters including applied frequency, distance between transmitter (TX) and receiver (RX), bending, contact area between the contiguous models, and induced current were investigated. The results show that the transmission loss increases with the increase of the transmission length and operating frequency. The electrical potential is directly proportional to the induced current. Bending helps to improve the detected signal in the cases of short distance between TX and RX around the curvature. For distant transceivers, both straight and bended models tend to behave in a close manner. However, no joints are added to the model. The signal degradation in inter-body communication is considerably higher compared to intra-body communication at the same horizontal distance between TX and RX. At frequencies above 200 kHz, both inter-body and intra-body communication give close values when the contact area between the arms covers the distance between TX and RX electrodes. In addition, by increasing the contact area and avoiding gaps between the models, the detected signal is improved. The results illustrate the main determinants of information transmission between both sensors within a body-sensors-network and between different person. <br
Keywords: Cole-Cole expressions; dielectric properties; human tissue; finite element model; galvanic coupling; human body communication; inter-body communication; intra-body communication

Silicon-Based RF System and Circuit Design for 3G W-CDMA Mobiles - Weigel, Robert; Maurer, Linus; Springer, Andreas (International Symposium on Signals, Systems, and Electronics, 2001)
elib2cris::1512001600,weigel2001e

Simple Mathematical Operation-Based Calibration Method for Giant Magnetoresistive Current Sensor Applying B-Spline Modeling - Xie, Fei; Weiß, Roland; Weigel, Robert (IEEE Sensors Journal, 2016)
Nowadays, giant magnetoresistance (GMR)-based sensor technology is widely used in numerous industrial applications. However, an inexpensive and efficient method for compensating the nonlinear output of GMR spin valve sensors is still under the industrial prospect, which limits the application of the GMR sensors. By applying the B-Spline modeling, excellent results can be achieved; nevertheless, the sensor has to be calibrated in the whole temperature range. In this paper, a simple mathematical operation-based calibration method for GMR spin valve-type current sensors applying B-Spline modeling is introduced. Instead to measure dozens of temperatures and per temperature several hundreds of points, this method allows a calibration for each further sensor applying B-Spline modeling with only two temperatures and per temperature only 15 points. In comparison with the original calibration measurement over temperature for B-Spline modeling, the new calibration with minimized efforts shows outstanding measurement accuracy of ±0.6% at a nominal current of 50 A in a temperature range from -20 °C to 80 °C.

Simulating large neural networks embedding MLC RRAM as weight storage considering device variations - Fritscher, Markus; Knödtel, Johannes; Reiser, Daniel; Mallah, Maen; Pechmann, Stefan; Fey, Dietmar; Reichenbach, Marc (Proc. of 12th IEEE Latin America Symposium on Circuits and System, 2021)

Simulating the Phase Noise Performance of a 4 GHz Voltage-Controlled Oscillator - Pichler, Markus; Weigel, Robert (Proc IEEE International Workshop on Commerical Radio Sensing and Communication Techniques, 2001)
elib2cris::1512001600,pichler2001

Simulation and Design of RF Oscillators - Eichinger, Ludwig; Sischka, F.; Olbrich, Gerhard; Weigel, Robert (International Workshop on Sip/soC Integration of MEMS and Passive Components with RF-ICs, 2004)
elib2cris::1512001600,eichinger2004

Simulation and Implementation Demands for State-of-the-Art Integrated Linear Power Amplifiers - Zohny, Amr; Rascher, Jochen; Weigel, Robert (Electrical and Electronic Engineering for Communication EEEfCOM 2012, 2012)
elib2cris::1512001600,zohny2012
Keywords: Linearity; Power Amplifier; CMOS; ACPR; Intermodulation

Simulation and Manufacturing of Low Loss PCB Structures with Additional Electromagnetic Field in Air - Sepaintner, Felix; Scharl, Andreas; Röhrl, Franz Xaver; Bogner, Werner; Zorn, Stefan (IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP), 2019)
This paper presents a new method to produce different kinds of RF waveguides with reduced attenuation on low cost PCB substrates. First, microstrip (MS) and grounded coplanar waveguides (GCPW) are characterized by considering rough conductors in CST Microwave Studio. Next, laminate is partially removed, to increase the electromagnetic field ratio in air. Accordingly, the dielectric losses are reduced and the electrical length is decreased. These conductors are produced by using a CO 2 laserdrilling machine to remove the undesired substrate. The RF performance (DC to 100 GHz) of these waveguides is compared to transmission lines manufactured in conventional PCB technology. Finally, different kinds of simulated and produced microstrip filters are shown and fabrication tolerances are compared to those produced in standard technology.<br
Keywords: low loss transmission lines; reduced tolerances; microstrip filters; sequential pre etching (SPE); wet-chemical etching; low cost PCB substrate

Simulation and Measurement of PCB Crossover Structures from DC up to 70 GHz - Scharl, Andreas; Sepaintner, Felix; Röhrl, Franz Xaver; Bogner, Werner; Zorn, Stefan (German Microwave Conference (GeMiC), 2020)
In this paper, 4 different crossover structures in a 6- layered printed circuit board (PCB) for high operation frequencies are presented. The design for all structures is based on grounded coplanar waveguide (GCPW). Two fully planar structures, a quasi-coaxial transition and coaxial transition are realized and have a measured bandwidth from DC to 50 GHz and DC to 60 GHz, respectively. Moreover, two structures are designed in submount technology. Especially the connection between baseboard and package (solder junction) plays an important role to guarantee best signal integrity. Therefore, the quality of the solder junction is analysed in detail with TDR (time domain reflectometry) measurement as well as with X-ray images. The submount transitions show good radio frequency (RF) characteristics from DC to 70 GHz.<br
Keywords: crossover; single ended transition; quasi-coaxial transition; coaxial transition; millimeter wave; RF package; DC to 70 GHz; wideband; land grid array; submount technology

Simulation and verification of a spread spectrum wireless LAN using SAW chirped delay lines - Gugler, Wolfgang; Huemer, Mario; Springer, Andreas; Pohl, Alfred; Reindl, Leonhard; Weigel, Robert; Seifert, Franz (IEEE Fifth International Symposium on Spread Spectrum Techniques and Applications, 1998)
We present a wireless spread spectrum system based on SAW chirped delay lines on LiTaO3-X112rotY operating in the ISM band at 2.45 GHz. The center frequency, transmission bandwidth, chirp rate, and data rate are 348.8 MHz, 80 MHz, ±40 MHz/μs, and 2 Mbits/s, respectively. Due to the reduction of the sidelobes of the compressed pulse to -42 dB, a high processing gain of 22 dB, and the large transmission bandwidth our system is robust against narrowband fading and noise. This paper describes the design, technology and measurement results of the used SAW chirped delay lines. The proposed communication system and simulation results are presented, measurements obtained with a hardware demonstrator are given, and the limiting factors of the data rate of our system are shown.
elib2cris::1512001600,gugler1998

Simulation-based Models of the Galvanic Coupling Intra-body Communication - Ahmed, Doaa; Fischer, Georg; Kirchner, Jens (2019 IEEE Sensors Applications Symposium, 2019)
Human body communication (HBC) uses the human body as a transmission medium for electrical signal at very low power consumption. In this paper, we provided two simulationbased arm models. In the first model, we studied the effect of introducing different types and thicknesses of tissues in the path of signal transmission on the detected signal. In the second model, we introduced different bending angles to the model and examined its effect on the detected signal. The results showed that the signal attenuates very rapidly in the skin tissue, although it has the lowest conductivity. On the other hand, no signal decay is noticed in the fat tissue. Despite the highest attenuation constant of the muscle tissue, adding it the model improves the detected signal at receiver. Increasing the thickness of the muscle layer reduces the electric potential difference at transmitter, while improves the detected signal at receiver. For the bended model, we found that the bending helps to improve the received signal at small angles because the signal takes the shortest path from transmitter to receiver. For larger angles, the discrepancy between this short path and main transmission length will be reduced until they are equal at angle 180°.<br
Keywords: human body communication; intra-body communication; galvanic coupling; simulation

Simulation Based Optimization of Phase Tracking Algorithms for IEEE 802.11a and Hiperlan/2 like OFDM Systems - Hausner, Josef; Witschnig, Harald; Huemer, Mario (Proc. 6th World Multiconference on Systemics, Cybernetics and Informatics, 2002)
elib2cris::1512001600,hausner2002

Simulation Environment of a Communication System Using CDMA at 77 GHz - Lübke, Maximilian; Fuchs, Jonas; Shatov, Victor; Dubey, Anand; Weigel, Robert; Lurz, Fabian (2020 International Wireless Communications and Mobile Computing, IWCMC 2020, 2020)
In this paper, an overall concept for a joint communication-sensing system at 77 GHz is presented with special focus on the communication part. To take advantage of the reduced interference between vehicles, code division multiplexing using direct sequence spread spectrum signals is applied. The system, which covers the whole signal processing chain, is introduced, explained and simulated using Simulink/Matlab software. A design, capable of spreading, modulating, including non-idealities of radio frequency-blocks and synchronization, is built up and evaluated. Additionally, a channel model is simulated in the software WinProp and integrated in the Simulink simulation. In consequence, a more realistic model compared to an estimation-based Rician-or Rayleigh channel model is realized. Furthermore, different modulation schemes, binary phase shift keying, 4- and 16-quadrature amplitude modulation, are investigated. The system is rated with respect to the bit-error-rate by applying additive white Gaussian noise. The functionality is verified as the the results match with the theoretical assumptions The system is further improved by building up a Rake-Receiver structure.
CRIS-Team Scopus Importer:2020-08-28
Keywords: 77 GHz; direct spread spectrum communication; joint sensing-communications; rake demodulator

Simulation Model for Performance Analysis of UMTS-Networks with Variable Data Rate - Ferizi, Alban (2006)

Simulation of a SAW-based spread spectrum wireless LAN - Gugler, Wolfgang; Huemer, Mario; Springer, Andreas; Weigel, Robert (IASTED International Conference on Signal Processing and Communications, 1997)
elib2cris::1512001600,gugler1997

Simulation of a SAW-based WLAN using chirp-pi/4 DQPSK modulation - Gugler, Wolfgang; Springer, Andreas; Kuepfer, H.P.; Weigel, Robert (1998 IEEE Ultrasonics Symposium, 1998)
We report on the simulation of a wideband (>50 MHz) spread spectrum system with a spreading bandwidth greater than the coherence bandwidth of the radio channel. SAW filters are used to produce the desired spread spectrum signals (chirp signals) and for matched filtering. Center frequency, transmission bandwidth, and chirp rate of the system are 348.8 MHz, 80 MHz, and ±160 MHz/μs, respectively. By using weighted chirps to reduce the sidelobes of the compressed pulse to -22 dB, π/4 DQPSK modulation as well as overlapping chirp signals, we get a data rate of more than 70 Mb/s. Considering a channel as suggested in the IEEE 802.11 standard for the indoor environment we achieve an improvement of the bit-error-rate (BER) over traditional π/4 DQPSK modulation because of the processing gain due to the pulse compression. The limiting factors of the data rate were found to be intersymbol interference and multipath fading.
elib2cris::1512001600,gugler1998a

Simulation of a UHF-Band Indoor Wireless TCDMA System Based on Multipath Fading Radio Channel Modeling - Zhang, Zhongping; Seifert, Franz; Weigel, Robert (Proc. IEEE Microwave Systems Conference, 1995)
A hybrid access scheme called time code division multiple access (TCDMA) is proposed for indoor wireless communications. The indoor radio channel is modeled in terms of channel impulse response 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 system performance reveal the capability and the capacity of TCDMA in a typical indoor cell such as in an office building of medium size
elib2cris::1512001600,zhang1995b
Keywords: TCDMA; communication; radio; channel; wireless

Simulation of Automotive EMC Emission Test Procedures Based on Cable Bundle Measurements - Gonser, Markus; Keller, Christian; Hansen, Jan; Khilkevich, Victor; Radachenko, Andriy; Weigel, Robert; Pommerenke, David (IEEE MTT-S International Symposium Digest (IMS), 2012, 2012)
Two time efficient simulation methods for the prediction of the conducted and radiated automotive EMC emission tests, respectively, are presented. To verify the correct prediction of the cable bundle model, a novel cable bundle test bench has been developed. It allows a fully automated network analysis with up to 32 ports. Several types of cable bundles are experimentally characterized under stochastic considerations. The system simulation for the conducted emission setup is partitioned into four parts connected on circuit level. The statistically analyzed voltage at the output of the line impedance stabilization network is in very good agreement to respective measurements. To simulate the radiated emission a novel method is presented, where the setup is partitioned by the use of Huygens principle. The simulated prediction of the antenna voltage is in good agreement with respective measurements. The presented approaches are very time efficient and therefore can be used effectively during product development.
elib2cris::1512001600,gonser2012
Keywords: Antenna measurements; Electromagnetic compatibility; Integrated circuit modeling; Numerical models; Power cables; Stochastic processes

Simulation of SAW Filters as Planar Waveguides with N Segments - Jungwirth, Mario; Pöcksteiner, Norbert; Weigel, Robert (Austrian Acoustics Association Fachtagung, 2000)
For the simulation of SAW-filters it can be useful to model the filters as planar waveguides, consisting of several segments with assigned material parameters (phase velocities, stiffness constants). In the case of complex structures (such as transversely coupled resonator filters) a transverse velocity profile consisting of more (N) segments can be determined. For such structures the present work provides the complete analysis based on a scalar potential as the wave-describing quantity. We obtain a complete set of orthonormal modes into which a transverse excitation can be expanded in order to study its propagation. The general mode spectrum consists of a discrete spectrum of bound modes, a continuous spectrum of semi-bound modes and finally a continuous spectrum of radiation modes. As to radiation modes, two solutions per eigenvalue exist, therefore they must be orthogonalized to enable expansion with a scalar product. Furthermore, anisotropy is dealt with by a parabolic approximation of the phase velocities. In general, a very good agreement between theoretical and experimental results has been achieved
elib2cris::1512001600,jungwirth2000
Keywords: SAW Filter; Waveguides

Simulations of a New Design Concept for Hybrid Ladder Filters - Wagner, Michael; Gossmann, Timo; Tomasik, Jakob; Weigel, Robert; Hagelauer, Amelie Marietta (2019 IEEE 20th Wireless and Microwave Technology Conference, WAMICON 2019, 2019)
In this paper, a new concept from circuit design perspective is presented and evaluated based on simulations. The concept allows for manipulation of the fixed behavior and limited effective electromechanical coupling factor (k-eff^2) of acoustic-wave resonators by additional lumped-element resonators. This hybrid approach enables resonance spreading of single acoustic-wave resonators and can be used for wide-band filter designs. A theoretical description of the concept is given and its benefits and application to filter design are outlined. Important characteristics are illustrated by a design example.
CRIS-Team Scopus Importer:2019-08-06

Simulation Test System for Development and Testing of Electrical Drive Systems - Franchi, Norman; Wellmann, Sebastian (Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH, 2011)
The proposed approach focuses on the realization of a modular test stand concept for electrical drives that combines automated, high-quality and precise Hardware-in-the-Loop simulation testing with the development of the corresponding embedded control software. The real system under test consists of an electronic control unit, the corresponding electrical engine and a controllable dynamometer for dynamic load emulation.
elib2cris::1512001600,franchi2011
Keywords: Electrical Drives; Engine Test Stand; Hardware-in-the-Loop; Control Prototyping; Dynamic Load Emulation; Modular Design; Combined Development and Test Environment

Simulation und Analyse von Substratkopplungen in Triple-Well BiCMOS-Technologien - Brandtner, Thomas; Weigel, Robert (Analog, 2002)
elib2cris::1512001600,brandtner2002a

Simulation von FMCW-Synthesizern mittels optimierter Verhaltensmodelle - Ußmüller, Thomas; Fischer, Georg; Weigel, Robert (Radcom - Radar, Communication and Measurement, 2011)
elib2cris::1512001600,ussmueller2011a

Simultaneous Inductive Power and Data Transmission System for Smart Applications - Trautmann, Martin; Sanftl, Benedikt; Weigel, Robert; Kölpin, Alexander (Ieee Circuits and Systems Magazine, 2019)
Inductive power transfer (IPT) development is a big issue amongst the scientific community but there are only few solutions for communication between the primary and secondary side. This article presents a completely contactless near field system, which can provide power and data simultaneously using one common inductive power link. In this novel approach both transmission channels are designed collaboratively to maximise their performance. Based on these joint system specifications, the requirements for each system are derived, analysed, simulated and measured. From this measurement the performance of the system is classified. To verify the joint specifications, the mutual interferences are evaluated and the system is compared to the state of the art. As a result, a prototype, which can provide 20W of power with a simultaneous data transfer of 461 kbit/s, is presented. With tested bit error rates smaller than 10-6, this communication link is a fully classified robust and reliable data link for IPT application

Simultaneous Step Counting and Energy Harvesting from Piezoelectric Discs Embedded in a Shoe - Gogoi, Niharika; Kirchner, Jens; Fischer, Georg; Zhu, Yuanjia (IEEE Sensors, 2022)
The main goal of this paper is to demonstrate that simultaneous sensing and energy harvesting from a piezoelectric element is feasible, instead of two separate systems, which ensures savings on cost and complexity. In our work, two types of interface circuitry to harvest energy from multiple piezoelectric elements embedded in a shoe are analysed. The harvested output is utilized to perform step counting of the subject wearing it.
Keywords: piezoelectric; sensing; wearable; energy harvesting; shoe; circuit

Simultane Übertragung von Leistung und Daten über induktiv gekoppelte Spulen mittels OFDM - Sanftl, Benedikt; Trautmann, Martin; Weigel, Robert; Kölpin, Alexander (Kleinheubacher Tagung 2017, 2017)

Single- and Dual-Port 50-100-GHz Integrated Vector Network Analyzers With On-Chip Dielectric Sensors - Nasr, Ismail; Nehring, Johannes; Aufinger, Klaus; Fischer, Georg; Weigel, Robert; Kissinger, Dietmar (IEEE Transactions on Microwave Theory and Techniques, 2014)
This work presents a single- and dual-port fully integrated millimeter-wave ultra-broadband vector network analyzer. Both circuits, realized in a commercial hbox0.35-muhbox m SiGe:C technology with an f_t/f_max of hbox170/250 GHz, cover an octave frequency bandwidth between 50–100 GHz. The presented chips can be configured to measure complex scattering parameters of external devices or determine the permittivity of different materials using an integrated millimeter-wave dielectric sensor. Both devices are based on a heterodyne architecture that achieves a receiver dynamic range of 57–72.5 dB over the complete design frequency range. Two integrated frequency synthesizer modules are included in each chip that enable the generation of the required test and local-oscillator millimeter-wave signals. A measurement 3sigma statistical phase error lower than 0.3^circ is achieved. Automated measurement of changes in the dielectric properties of different materials is demonstrated using the proposed systems. The single- and dual-port network analyzer chips have a current consumption of 600 and 700 mA, respectively, drawn from a single 3.3-V supply.
elib2cris::1512001600,nasr2014a

Single Carrier Transmission with Frequence Domain Equalization: An Overview - Koppler, Alois; Witschnig, Harald; Weigel, Robert; Huemer, Mario (Proc. IEEE Internation Symposium on Theoretical Electrical Engineering, 2001)
elib2cris::1512001600,koppler2001a

Single Carrier Transmission with Frequency Domain Equalization: A Comparison with Hiperlan/2-like OFDM Systems - Koppler, Alois; Huemer, Mario; Reindl, Leonhard; Springer, Andreas; Weigel, Robert (Proc. 4th European Personal Mobile Communications Conference, 2001)
elib2cris::1512001600,koppler2001

Single Carrier Transmission with Frequency Domain Equalization for Ultrabroadband Communication System - Huemer, Mario; Ruppel, Clemens; Reindl, Leonhard; Springer, Andreas; Weigel, Robert (The Book of Visions 2001, 2001)
elib2cris::1512001600,huemer2000c
Keywords: Ultrabroadband; Single Carrier

Single-Chip 19 and 24 GHz VCO and Frequency Divider Fabricated in a Commercial SiGe Bipolar Technology - Ettinger, Klaus; Stelzer, Andreas; Höftberger, Josef; Diskus, Christian; Fenk, Josef; Weigel, Robert (Microwave Conference, 2002. 32nd European, 2002)
This paper presents the design, implementation and testing of fully integrated 19 and 24 GHz voltage controlled oscillator chips for RADAR distance sensor applications. The oscillators are integrated on one chip together with a frequency divider with a divide ratio of 16 and 32, as well as an output driver. The chips are fabricated in a production SiGe bipolar technology and have an area of 960 Ã Â 960 Ã Â¿m2 each. Both VCOs are varactor-tuned LC-type oscillators with a tuning range of about 1 GHz featurng different inductors and transistors. Both chips work from a single 3.6 V supply, the 24 GHz VCO draws 6 mA and the 19 GHz VCO draws 9 mA of supply current, respectively. Divider and output driver consume 23 mA and 51 mA, respectively. The measured phase-noise of the 19 GHz VCO is about Ã Â¿100 dBc/Hz at 1 MHz offset frequency, whereas the 24 GHz VCO features a phase-noise of about Ã Â¿89 dBc/Hz.
elib2cris::1512001600,ettinger2002a
Keywords: Driver Circuits; Frequency Conversion

Single-Chip 20 GHz VCO and Frequency Divider in SiGe Technology - Ettinger, Klaus; Stelzer, Andreas; Diskus, Christian; Thomann, Wolfgang; Fenk, Josef; Weigel, Robert (IEEE MTT-S International Microwave Symposium Digest, 2002)
This paper presents the design, implementation and testing of a fully integrated 20 GHz voltage controlled oscillator, a frequency divider with a divide ratio of 16, as well as an output driver. All blocks are integrated on one IC with an area of 890 × 890 μm 2 and are fabricated in a production SiGe bipolar technology. The VCO is a varactor-tuned LC-type oscillator with a tuning range of 600 MHz. The differential signal of the output driver is converted to a single-ended signal by an external microstrip balun and delivers a maximum of 2 dBm of output power into a 50 Ω load. The chip works with a single supply voltage of 3.6 V, the VCO draws 12 mA of supply current, divider and output driver consume 17 mA and 51 mA, respectively. The measured phase-noise of the VCO is -85 dBc/Hz at 1 MHz offset frequency
elib2cris::1512001600,ettinger2002
Keywords: Bipolar integrated circuits; Frequency conversion

Single-Element Based Ultra-Wideband Antenna Array Concepts for Wireless High-Precision 2D Local Positioning - Gardill, Markus; Fischer, Georg; Weigel, Robert; Kölpin, Alexander (Advances in Radio Science : Kleinheubacher Berichte, 2013)
We generally categorize the approaches for ultrawideband antenna array design, and consequently propose simplified concepts for antenna arrays for a high-precision, ultra-wideband FMCW radar 2D local positioning system to obtain robustness against multi path interference, perform angle of arrival analysis, as well as instantaneous heading estimation. We focus on low-cost and mechanical robust, industrial-application ready antennas. The antenna arrays are optimized for operation in the 5 GHz to 8 GHz frequency range and are designed towards supporting full omnidirectional 360 as well as partial half-plane direction of arrival estimation. Two different concepts for vehicle- as well as wall-mounted antenna array systems are proposed and discussed. We propose a wideband unidirectional bow-tie antenna array element having 97% impedance and 37% pattern bandwidth and a robust vehicle mounted omnidirectional antenna element having more than 85% impedance and pattern bandwidth.
elib2cris::1512001600,gardill2013

Single-Ended Ultra-Low-Power Multistage Rectifiers for Passive RFID Tags at UHF and Microwave Frequencies - Seemann, Kay; Hofer, Günter; Cilek, Fatih; Weigel, Robert (IEEE Radio and Wireless Symposium, 2006, 2006)
The commercial significance of ubiquitous chips, especially of radio frequency identification devices (RFID), and the advantages compared to other identification technologies, for e.g. the barcode, has been discussed in several papers. In order to achieve higher operational distances and to improve the operational reliability of passive RFID tags, the design of integrated circuits with ultra-low power consumption and novel concepts for high-efficiency energy scavenging are an emerging task. This article deals with general limitations and novel systematically design approaches concerning rectification circuits for ultra-low power levels at UHF (ultra high frequencies) and microwave frequencies. By using the presented characteristic parameters it is possible to optimize multi-stage rectifiers at the ultra-low power domain and to verify the applicability of a given solid-state and assembly technology.
elib2cris::1512001600,seemann2006
Keywords: UHF circuits; microwave circuits; passive networks; radiofrequency identification; rectifying circuits; assembly technology; integrated circuits; Microwave circuits

Single Shot Positioning with the HIGAPS Receiver - Kaniuth, Roland; Eissfeller, Bernd; Lemke, Norbert; Heinrichs, Günther; Ehm, Henning; Weigel, Robert; Schmid, Andreas; Neubauer, André; Nagel, Peter (European Navigation Conference (ENC-GNSS), 2005)
In this paper an overview of the HIGAPS project is given and the different development and test platforms a briefly introduced. A description on the proposed single-shot positioning algorithm for location based services is given and finally, test and performance results are shown.
elib2cris::1512001600,kaniuth2005a

Single-Snapshot Direction-of-Arrival Estimation of Multiple Targets using a Multi-Layer Perceptron - Fuchs, Jonas; Weigel, Robert; Gardill, Markus (2019 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), 2019)
An alternative approach to high-resolution direction-of-arrival estimation in the context of automotive FMCW signal processing is shown by training a neural network with simulation as well as experimental data to estimate the mean and distance of the azimuth angles from two targets. Testing results are post-processed to obtain the estimated azimuth angles which can be validated afterwards. The performance of the proposed neural network is then compared with a reference implementation of a maximum likelihood estimator. Final evaluations show super-resolution like performance with significantly reduced computation time, which is expected to have an impact on future multi-dimensional high-resolution DoA estimatio
Keywords: Direction-of-arrival estimation; Training; Neural networks; Radar; Maximum likelihood estimation; Signal to noise ratio; Automotive Radar; Direction-of-Arrival Estimation; Neural Network; Multi-Layer Perceptron

Single-Substrate High-T/sub c/ Superconducting Coplanar Oscillator at 6.5 GHz - Klieber, Ralf; Ramisch, Roland; Weigel, Robert; Schwab, Martin; Valenzuela, Alejandro; Dill, Roland; Russer, Peter (Asia-Pacific Microwave Conference (APMC), 1992, 1992)
The design and performance of a planar, low-noise cryogenic oscillator operating at 6.5 GHz and 77 K are presented. The device is entirely fabricated on a 10x10 mm² LaAlO₃ substrate with a superconducting YBa₂Cu₃O₇₋x thin-film as the conductor material. At a power output of 4.9 dBm, we attain a single-sideband phase noise to carrier ratio of -90 dBc/Hs at 10KHz offset. The attenuation of harmonics was better that 10 dBc.
elib2cris::1512001600,klieber1992a
Keywords: Coplanar waveguides; Cryogenics; Frequency; High temperature superconductors; Oscillators; Substrates; Superconducting materials; Superconducting microwave devices; Superconducting thin films; Thin film circuits

Six-Port Based Direction Finding and Micrometer-Accuracy Displacement Detection - Vinci, Gabor; Barbon, Francesco; Lämmle, Benjamin; Weigel, Robert; Kölpin, Alexander (CST European User Group Meeting (CST EUGM) 2012, 2012)
elib2cris::1512001600,vinci2012c
Keywords: Six-Port

Six-Port Based Direction Finding and Ranging - Kölpin, Alexander; Weigel, Robert (20th International Conference on Microwaves, Radar, and Wireless Communications, 2014)
The Six-Port concept is known since decades as a precise device for complex valued signal handling. It has shown its functionality for metrology applications as well as for broadband I/Q data reception. Due to its extraordinary phase resolution and low cost implementation two specific industrial applications get more and more into focus: Six-Port based distance measurements and direction finding. In this paper a review on this promising concept will be given for both, ranging and angle of incident detection featuring sub-millimeter range resolution and measurement value update rates in the two digit kilohertz range. Furthermore, similarities and differences of Six-Port technology with common radar concepts will be discussed.
elib2cris::1512001600,koelpin2014b
Keywords: Six-Port; Direction Finding; AoA; Ranging; Radar

Six-Port Based Direction Finding and Ranging - Vinci, Gabor (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2014)

Six-Port-Based Direction-Of-Arrival Detection System - Vinci, Gabor; Kölpin, Alexander; Barbon, Francesco; Weigel, Robert (Asia-Pacific Microwave Conference, 2010)
Direction-Of-Arrival (DOA) detection is a fundamental procedure required by several monitoring and tracking systems for defense purposes and other security applications as well as industrial monitoring and measurement. The ability of a system to accurately determine the incident angle of an arbitrary electromagnetic wave incoming toward the observer device is an important as well as challenging task especially when low-cost and robustness are also key points for the overall tracking and detection or surveillance solution. Phase-measurement based DOA detection is commonly used in nowadays systems, but existing methods are based on traditional mixer architectures or expensive direct conversion devices increasing complexity and cost while compromising robustness. In this paper an innovative, robust and accurate technique is proposed to perform the DOA detection by means of Six-Port based Phase Measurement Detection.
elib2cris::1512001600,vinci2010a

Six-Port Based High-Resolution Smart Antenna Alignment Sensor - Vinci, Gabor; Barbon, Francesco; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, 2012)
For several wireless data transmission systems the relevance of the information is dependent on the position of the information source. Therefore, Direction Of Arrival (DOA) detection of an incoming radio frequency signal is for several applications an important task. Typical applications for which DOA detection is relevant are for instance high-accuracy indoor navigation systems and dedicated high-speed wireless data links. For accurate DOA analysis a six-port receiver front-end is proposed. Benefits of the six-port architecture are high bandwidth and low circuit complexity. A solution for simultaneous data reception and DOA detection with the enhanced six-port receiver concept is also presented.
elib2cris::1512001600,vinci2012e
Keywords: Antenna measurements; Microwave communication; Receiving antennas; Wireless sensor networks; Six-Port; Enhanced Six-Port; Smart Antenna

Six-Port Based Interferometry for Precise Radar and Sensing Applications - Kölpin, Alexander; Lurz, Fabian; Linz, Sarah; Mann, Sebastian; Will, Christoph; Lindner, Stefan (Sensors, 2016)
elib2cris::1512001600,koelpin2016

Six-Port-Based Microwave Spectroscopy of Dielectric Materials for Non-Invasive ISM Applications - Hofmann, Maximilian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

Six-Port Based Multitone and Low-Power Radar System for Waveguides in Smart Factories - Scheiner, Benedict; Lurz, Fabian; Michler, Fabian; Linz, Sarah; Weigel, Robert; Kölpin, Alexander (Proceedings of the 48th European Microwave Conference, 2018)

Six-Port Microwave Interferometer Radar for Mechanical Vibration Analysis - Vinci, Gabor; Lindner, Stefan; Mann, Sebastian; Barbon, Francesco; Linz, Sarah; Weigel, Robert; Kölpin, Alexander (European Radar Conference (EuRAD), 2013)
elib2cris::1512001600,vinci2013a

Six-Port Radar Sensor for Remote Respiration Rate and Heartbeat Vital-Sign Monitoring - Vinci, Gabor; Lindner, Stefan; Barbon, Francesco; Mann, Sebastian; Hofmann, Maximilian; Duda, Alexander; Weigel, Robert; Kölpin, Alexander (IEEE Transactions on Microwave Theory and Techniques, 2013)
A novel remote respiration and heartbeat monitoring sensor is presented. The device is a monostatic radar based on a six-port interferometer operating a continuous-wave signal at 24 GHz and a radiated power of less than 3 μW . Minor mechanical movements of the patient's body caused by the respiration as well as heartbeat can be tracked by analyzing the phase modulation of the backscattered signal by means of microwave interferometry with the six-port network. High-distance measurement accuracy in the micrometer scale as well as low system complexity are the benefits of the six-port receiver. To verify the performance of the system, different body areas have been observed by the six-port radar. The proposed system has been tested and validated by measurement results.
elib2cris::1512001600,vinci2013
Keywords: radars; radar systems; bio effects and med. appl. of RF/Microwave; biomedical applications; biomedical sensors

Six-Port Receiver Analog Front-End for Direct Conversion - Kölpin, Alexander (Proceedings of the 1st Chinese-German Summer School (Embedded Systems and Materials - Research for Advanced Applications), 2006)
elib2cris::1512001600,koelpin2006a

Six-Port Receiver Analog Front-End: Multilayer Design and System Simulation - Winter, Sebastian; Kölpin, Alexander; Weigel, Robert (IEEE Transactions on Circuits and Systems II: Express Briefs, 2008)
In this paper, a six-port receiver analog front-end structure based on a Wilkinson power divider and three hybrid couplers is presented, which has been implemented in a multilayered, meandered manner, yielding a size reduction of about 78% compared to a planar design. The measured S-parameters of the new design are in good accordance with simulated S-parameters of the planar structure. System simulations with an orthogonal frequency division multiplexing signal show the suitability of the design for six-port communications receivers.
elib2cris::1512001600,winter2008a
Keywords: OFDM modulation; S-parameters; power dividers; radio receivers; S-parameters; Wilkinson power divider; hybrid couplers; planar structure

Six-Port Receiver Local Oscillator Power Selection for Maximum Output SNR - Winter, Sebastian; Ehm, Henning; Kölpin, Alexander; Weigel, Robert (IEEE Radio Wireless Symposium, 2008)
elib2cris::1512001600,winter2008

Six-Port Technology for Precise Geometrical Measurement Applications - an Overview - Kölpin, Alexander; Vinci, Gabor; Lindner, Stefan; Mann, Sebastian; Barbon, Francesco; Linz, Sarah; Oesterle, Florian; Weigel, Robert (European Microwave Conference (EuMC), 2013)
Instrumentation for precise geometrical measurements based on radar technology get more and more important for industrial applications. Besides distance, determining an angle or modal analysis of vibrations are key issues for automation in modern fabrication. Industrial applications put high demands on the measurement systems, not only regarding precision but also concerning operation in harsh environments and low cost implementations. In the last years Six-Port technology got more and more important for these applications. This paper will give an overview of Six-Port technique for geometrical distance measurements.
elib2cris::1512001600,koelpin2013b

Six-Port Technology for Traffic Safety - Kölpin, Alexander; Vinci, Gabor; Lämmle, Benjamin; Lindner, Stefan; Barbon, Francesco; Weigel, Robert (IEEE Microwave Magazine, 2012)
The market for driver-assistance systems for modern automobiles is rapidly growing. Formerly only provided for the luxury automotive market, these systems are nowadays more and more available for mid- and compact-class vehicles as well. This development is not only limited to the passenger car segment but is also more and more important for commercial vehicles and trucks. Some driving assistance systems have already become mandatory, e.g., the antilock breaking system (ABS). Some governments are currently thinking about requiring automatic distance control by law for heavy trucks. Automatic distance control in combination with an automatic emergency breaking system is one of the rising stars for enhancing traffic safety. Radar- based distance control mostly interacts with cruise control systems and it adapts the speed of the driver's car to the distance to the car or obstacle in front of the vehicle. Furthermore, unavoidable accidents are detected and actions for reducing the effects of the crash are automatically initiated for some systems.
elib2cris::1512001600,koelpin2012b
Keywords: six-port; AoA

Smart Communication and Relative Localization System for Firefighters and Rescuers - Lurz, Fabian; Müller, Simon; Lindner, Stefan; Linz, Sarah; Gardill, Markus; Weigel, Robert; Kölpin, Alexander (IEEE International Microwave Symposium, 2017)

Smart Home low power wireless sensor network with localization functionality - Pflaum, Felix; Kölpin, Alexander (Workshop on Localization in Wireless Sensor Networks, 2017)

SmartHome Low Power Wireless Sensor Network with Localization Functionality - Pflaum, Felix; Kölpin, Alexander (Workshop on Resource-efficient Localization in Wireless Sensor Networks, 2017)

Smart Sensor Framework: A Pressure Sensor for Smart Home Applications - Lieske, Tobias; Schuklin, Dennis; Hohnloser, Daniel; Reichenbach, Marc; Pfundt, Benjamin; Fey, Dietmar; Weigel, Robert (1. E|HOME-CENTER SYMPOSIUM, 2016)

Software Defined Radio - A Technology Whose Time Has Come - Weigel, Robert; Maurer, Linus; Huemer, Mario; Burnic, A.; Scholand, Tobias; Viessmann, A.; Jung, P. (VDE-Kongress 2006, 2006)
elib2cris::1512001600,weigel2006

Spannungsgesteuerter Colpitts-Oszillator mit weitem Abstimmbereich in Silizium-Germanium-Technologie und Ausgangsschalter zur Generierung gepulster frequenzmodulierter Ultrabreitband-Signale - Eßwein, Alexander; Dehm-Andone, Gunther; Aleksieieva, Anna; Carlowitz, Christian; Fischer, Georg; Vossiek, Martin; Weigel, Robert; Ussmueller, Thomas (12. GMM/ITG-Fachtagung Analog 2011, 2011)
lhft_intern.bib::Esswein2011

SPARS — Simultaneous Phase and Amplitude Regenerative Sampling - Carlowitz, Christian; Vossiek, Martin; Girg, Thomas; Dietz, Marco; Schrotz, Albert-Marcel; Maiwald, Tim; Hagelauer, Amelie Marietta; Weigel, Robert; Ghaleb, Hatem; Carta, Corrado; Ellinger, Frank; Du, Xuan-Quang; et al. (Wireless 100 Gbps And Beyond. Architectures, Approaches and Findings of German Research Foundation (DFG) Priority Programme SPP1655, 2020)

Spatially resolved measurements and analysis of SAW propagation in piezoelectric crystals - Holm, Andreas; Weigel, Robert; Russer, Peter (Proc. URSI 25th General Assembly, 1996)
elib2cris::1512001600,holm1996

Spectral PLL built-in self-test for integrated cellular transceivers - Münker, Christian; Weigel, Robert (33rd European Solid State Circuits Conference ESSCIRC, 2007)
A built-in self test (BIST) solution for the on-chip spectral verification of a 4 GHz phase-locked loop (PLL) is presented. The PLL is embedded in an integrated cellular RF transceiver in a 130 nm CMOS technology. The BIST blocks enable the detection of catastrophic and many parametric faults by measuring the PLL frequency response and checking for spurious sidebands and excessive in-band phase noise without external test equipment. Multi-tone stimuli with a spurious-free dynamic range (SFDR) of 60 dB are generated on-chip, the PLL RF response is demodulated and digitized in an on-chip digital FM discriminator. Spectral analysis is performed using digital narrowband filtering, achieving an SFDR of 45 dB. The fully digital BIST blocks require a chip area of only 0.06 mm2 and do not compromise the performance of the PLL itself.
elib2cris::1512001600,muenker2007a

Spectral PLL Built-In Self-Test for Integrated Cellular Transmitters - Münker, Christian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)

Spectrum-based Single-Snapshot Super-Resolution Direction-of-Arrival Estimation using Deep Learning - Gall, Maximilian; Gardill, Markus; Horn, Thomas; Fuchs, Jonas (2020 German Microwave Conference, GeMIC 2020, 2020)

Spectrum demand of professional wireless production tools (PMSE) : Study report - Fischer, Georg; Ackermann, Thomas (FAU University Press, 2022)
his study analyses trends in UHF spectrum use and demands by users of UHF spectrum. Thanks to availability of a large database that contains spectrum scans of a multitude of events over a large timespan, trends in availability of PMSE spectrum and PMSE use can be derived. Thereby conclusions are based on real world data from the field. A statistical modelling of available and used spectrum with PMSE is conducted. This allows for probabilistic conclusions when in future it will no longer be possible to use PMSE to an extend as initially planned. A shortage of PMSE frequencies at UHF is up on the horizon. When this scarcity becomes immanent is scientifically derived on the basis of stochastic considerations. As with earlier studies the role of technological advancements with PMSE, cellular and broadcast are discussed with respect to efficiency of spectrum use. Aside of technological trends there are also trends in society, like an increased awareness about inclusion, barrier-free access to events and remote participation, which are further drivers to larger PMSE use. Finally, this study will derive conclusions and derive recommendation towards Politicians, Regulation, Standardization, Mobile Network Operators and lastly PMSE and cellular equipment supplier
Keywords: PMSE; SDR; spectrum demand

Spectrum Sensing for Cognitive Wireless Applications Inside Aircraft Cabins - Heller, Christoph; Blümm, Christian; Bouckaert, Stefan; Wei, Liu; Moerman, Ingrid; van Wesemael, Peter; Pollin, Sofie; Solc, Tomaz; Padrah, Zoltan (IEEE Digital Avionics Systems Conference, 2012)
Wireless intra-aircraft communication is expected to be the enabler for more flexible avionic systems and the reduction of weight and cost in system installations. An alternative to the usage of a dedicated frequency band for wireless intra-aircraft avionics could be the usage of a virtually unregulated ISM band. Cognitive radio techniques could be used to increase system robustness in the likely case of interferences in this kind of frequency bands. A cognitive wireless cabin management system is discussed as a use-case for the validation of this approach. Using the mobile cognitive radio testbed of the FP7 project CREW, spectrum sensing experiments are carried out in a realistic aircraft cabin environment as a baseline for the development of suitable cognitive protocols and to record interference scenarios for the further system design.
elib2cris::1512001600,heller2012
Keywords: avionics; cognitive radio; protocols; radiofrequency interference; FP7 project CREW; aircraft cabin environment; cognitive protocols; cognitive radio techniques

Spektraler Selbsttest für HF PLLs in hochintegrierten Mobilfunktransceivern - Münker, Christian; Weigel, Robert (URSI Kleinheubacher Tagung 2008, 2008)
elib2cris::1512001600,muenker2008a

Spiking Neural Networks Design-Space Exploration Platform Supporting Online and Offline Learning - El-Masry, Moamen; Anees, Sohaib; Weigel, Robert (International System on Chip Conference, 2023)
As Spiking Neural Networks (SNNs) gain popularity, more SNN components are developed. SNN development requires a dedicated platform for testing and evaluating the various network components. This paper presents a novel system-on-module (SoM) for exploring spiking neural network hardware components based on a fully integrated platform. The platform is highly reconfigurable, allowing different modes of operation for SNN on/offline learning. The proposed fully integrated SoM platform was tested for its ability to perform learning recognition of random input patterns using the STDP learning algorithm. The results obtained using 28 nm CMOS technology demonstrate the feasibility of this approach.
CRIS-Team Scopus Importer:2023-11-03
Keywords: neuromorphic; non-volatile memory; offline learning; online learning; resistive-RAM; Spiking neural networks; STDP; system-on-module

Spiking Neural Networks for Gesture Recognition Using Time Domain Radar Data - Shaaban, Ahmed; Furtner, Wolfgang; Weigel, Robert; Lurz, Fabian (2022 19th European Radar Conference, EuRAD 2022, 2022)
Gesture recognition using luminance invariant radar sensors is vital due to its extensive use in human-machine interfaces. However, the necessity for computationally expensive radar data pre-processing steps represented by fast Fourier transforms to get range and Doppler features are regarded as a contemporary concern. In this work, we present a solution for gesture recognition that relies on time-domain radar data applied to an event-driven, sparse, and end-to-end trained spiking neural network architecture. Using the proposed solution, it is possible to discriminate between 10 different gestures in a gesture dataset recorded using a 60 GHz frequency-modulated continuous-wave radar sensor, with a mean test accuracy of 93.1%.
CRIS-Team Scopus Importer:2022-11-25
Keywords: Convolutional Neural Networks; FMCW Radar; Radar Gesture Recognition; Raw Radar Data; Spiking Neural Networks; Time Domain Radar Data

Spread spectrum communications using chirp signals - Springer, Andreas; Gugler, Wolfgang; Huemer, Mario; Reindl, Leonhard; Ruppel, Clemens; Weigel, Robert (IEEE/AFCEA EUROCOMM 2000. Information Systems for Enhanced Public Safety and Security, 2000)
We report on the use of broadband chirp signals for spread spectrum systems in indoor applications. The presented system concepts make use of chirp transmission and pulse compression. Different modulation schemes for the chirp signals resulting in different system performance and complexity are compared in terms of bit error rate for the AWGN channel and for frequency selective indoor radio channels. We present simulations and measurement results from demonstrator systems which use surface acoustic wave (SAW) devices for the generation and matched altering of the chirp signals. The RF and IF frequency and transmission bandwidth of the presented systems are 2.4 GHz, 348.8 MHz, and 80 MHz, respectively. Due to the processing gain of 16 dB-made possible by the use of SAW devices-and the large transmission bandwidth the system is insensitive against frequency selective fading, CW interference and noise
elib2cris::1512001600,springer2000
Keywords: System performance; Surface acoustic waves; Spread spectrum communication; RF signals; Chirp modulation; Pulse compression methods; Bit error rate; Bandwidth; AWGN channels

Squircle-Based Calibration Algorithm for Six-Port Radar - Linz, Sarah; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (IEEE Transactions on Microwave Theory and Techniques, 2019)

Stability of the Frequency Spectrum of the Heart Sounds S1 and S2 under Different Physiological Conditions - Zeising, Samuel; Thalmayer, Angelika; Fischer, Georg; Kirchner, Jens (The 20th IEEE International Conference on Bioinformatics and Bioengineering, 2020)

Stand der LED-Technik und Entwicklungsperspektiven - Werner, Daniel; Schwenzfeier-Hellkamp, Eva (LED-Beleuchtungssysteme: Technik, Kriterien und Umsetzung, 2013)

Static Magnetic Localization of Capsule Endoscopes: A Differential Method - Zeising, Samuel; Ararat, Kivanc; Thalmayer, Angelika; Fischer, Georg; Kirchner, Jens (COMSOL Conference 2020, 2020)

Status of Six-Port Technology for Wireless Sensing Applications - Haddadi, Kamel; Loyez, Christophe; Lallemand, Simon; Kölpin, Alexander (International Conference on Electromagnetics in Advanced Applications, 2018)
The status of the six-port technology for wireless sensing applications in the microwave and millimeter-wave regimes is discussed. The six-port technique has been introduced in the 1960’s for power measurement and vector network analysis. Thanks to reduced hardware resource in contrast with conventional and well-established down-mixing heterodyne technique, new opportunities can be foreseen to address future sensing applications in a broad range of topics.<br
Keywords: Six-port; microwave sensing; millimeter-wave; sensing; IQ demodulation

Steering Magnetic Nanoparticles by Utilizing an Adjustable Linear Halbach Array - Thalmayer, Angelika (FAU-Networking Night Medizintechnik (Poster Presentation), 2021)

Steering Magnetic Nanoparticles by Utilizing an Adjustable Linear Halbach Array - Thalmayer, Angelika; Zeising, Samuel; Fischer, Georg; Kirchner, Jens (Kleinheubacher Tagung 2021, 2021)

Stochastisches Kabelbaummodell und dessen messtechnische Validierung für Kabelbäume in EMV-Komponentenmessverfahren der Automobilindustrie - Gonser, Markus; Keller, Christian; Hansen, Jan; Weigel, Robert (EMV Düsseldorf, 2010)
Verschiedene Exemplare desselben Kabelbaums führen in EMV-Komponentenmessverfahren zu erheblichen Unterschieden in der Messgröße. Zur aussagekräftigen Simulation dieser Messverfahren früh im Entwicklungszyklus einer Komponente müssen alle geometrischen Variationsmöglichkeiten der Adern im Kabelbaum berücksichtigt werden. Wegen der Variationsvielfalt ist eine stochastische Betrachtung des Kabelbaums unumgänglich. Erst dann sind sichere Aussagen hinsichtlich der Grenzwerte der Normen möglich. Es wird ein stochastisches Kabelbaummodell entworfen, das durch zwei Kategorien von Parametern beschrieben wird, nämlich Ordnungs- und Geometrieparametern. Die mit diesem Modell erzeugten Realisierungen des Kabelbaums werden mittels der Leitungstheorie für Mehraderleitungen in einer Monte-Carlo-Simulation berechnet und anschließend statistisch ausgewertet. Für die richtige Wahl der Parameter des Modells und für den Nachweis der Fähigkeit des Modells, reale Kabelbäume abbilden zu können, werden für einige Kabelbäume je hunderte verschiedene Exemplare vermessen und statistisch ausgewertet. Für die vorgestellten Kabelbäume können Parameterkombinationen des Modells gefunden werden, die zu einer sehr guten Übereinstimmung zwischen Simulation und Messung führen. Es ergeben sich unabhängig von den Geometrieparametern immer die gleichen Werte für die Ordnungsparameter. Somit müssen für die Modellierung dieser Kabelbäume lediglich die leicht zu bestimmenden Geometrieparameter angepasst werden, während die Werte der Ordnungsparameter konstant bleiben.
elib2cris::1512001600,gonser2010

SubCalm: A Program for Hierarchical Substrate Coupling Simulation on Floorplan Level - Brandtner, Thomas; Weigel, Robert (Proceedings Design, Automation and Test in Europe Conference and Exhibition, 2004, 2004)
The hierarchical substrate coupling simulation tool Sub-CALM offers the opportunity to estimate substrate coupling on floorplan level. A novel approach for modeling well and SOI structures in a boundary element description is introduced. Several acceleration techniques like precalculated macromodels and sophisticated preconditioning algorithms are presented which are applied to an O(n)-conjugate-gradient Poisson solver in order to be able to process large full-chip layouts during floorplanning.
elib2cris::1512001600,brandtner2004
Keywords: circuit complexity; circuit layout CAD; circuit simulation; electromagnetic coupling; integrated circuit modelling; semiconductor quantum wells; Acceleration; CMOS technology

SubCALM: Ein simulationstool zur Abschaetzung von Substratkopplungen mit Hilfe von vorberechneten Makromodellen - Weigel, Robert; Brandtner, Thomas (Proc. Austrochip, 2002)
elib2cris::1512001600,weigel2002d

Subspace Based Identification of Broadband Electrical Models from Frequency Response Data - Stelzer, Andreas; Neumayer, Roland; Weigel, Robert (AEÜ - International Journal of Electronics and Communications, 2003)
The generation of broadband equivalent circuit models for time-domain analysis of complex structures or components characterized by frequency-dependent network parameters is of great interest in microwave theory. In this paper, a recently developed frequency-domain subspace identification algorithm is applied to generate multi-port circuit models for passive microwave devices characterized by admittance, impedance, or scattering parameter data. The proposed method combines non-parametric minimal order realization and efficient passivity check. It is suitable for simulating linear sub-networks characterized by frequency response data in a general circuit environment consisting of lumped/distributed elements and nonlinear devices. The synthesized networks are compatible with SPICE-based circuit simulators, as is demonstrated by numerical examples.
elib2cris::1512001600,stelzer2003

Substrate Integrated Waveguide Fed Antenna for 61 GHz Ultra-Short-Range Interferometric Radar Systems - Mann, Sebastian; Lurz, Fabian; Linz, Sarah; Lindner, Stefan; Will, Christoph; Wibbing, Sascha; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2016)
Radar sensors play a key role in today’s indus- trial automation. Being an alternative to frequency modulated continuous wave radar, Six-Port based radar sensors recently attracted the interest of the community as well as of the industry. This paper presents a 61 GHz Six-Port radar sensor for ultra-short range applications and a dedicated substrate integrate waveguide fed tapered slot antenna design. Due to an optimized design, the antenna allows for measurements in the direct near-zone of 0 mm to 10 mm without ambiguity effects. Making use of a spiral fitting operation, the presented measurement results show an absolute distance error of less than 100 μ
elib2cris::1512001600,mann2016
Keywords: Interferometer; Six-Port; RADAR; phase measurement; nearfield sensor; millimeter-wave

Substrate Integrated Waveguide Technology for mm-Wave Interferometric Radar Applications - Lurz, Fabian; Mann, Sebastian; Weigel, Robert; Kölpin, Alexander (European Microwave Week (EuMW), Worshop on Substrate Integrated Technologies and Applications, 2018)
SIW technology shows promising approaches for mm-Wave applications, especially for radar sensors. In this workshop, a complete 61 GHz six-port radar system will be presented, and the underlying system and circuit concepts are discussed. The radio frequency frontend is realized as system on substrate in a mixed SIW-micro-strip-technology to make the systems insensitive to external interference. The individual building blocks, such as the SIW fed Vivaldi antenna design, SIW coupler and power dividers, as well as the necessary transitions to the power detectors, attenuators and the MMICs are presented. Furthermore, measurements of the individual components and the complete system are shown.

Subthreshold-Standardzellen für Ultra Low Power-Wakeup-Schaltungen in drahtlosen Sensorknoten - Grimminger, Florian (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

Successive Interference Cancellation for SC/FDE-MIMO Systems - Reinhardt, Steffen; Buzid, Tufik; Huemer, Mario (International Symposium on Personal, Indoor and Mobile Radio Communication, 2006)
Several efforts are currently underway in investigating multiple-input multiple-output (MIMO) communication systems. MIMO technology promises high data rate wireless communications and/or the potentiality of exploiting transmit and receive diversity schemes. For WLAN (wireless local area networks) scenarios most investigations focus on OFDM (orthogonal frequency division multiplexing) transmission. In this paper we discuss spatial multiplexing in conjunction with optimal matched filtering and MMSE-equalization for SC/FDE (single carrier transmission with frequency domain equalization), a single carrier technology closely related to OFDM due to its frequency domain signal processing characteristics. We show that our MMSE equalizer derived in S. Reinhardt et al. (2006) can be further optimized by combining it with successive interference cancellation known from multiuser detection, which yields a novel structure for MIMO-SC/FDE systems similar to VBLAST (G.D. Golden et al., 1999), but adapted to SC/FDE and suited for transmission over frequency selective fading channels.
elib2cris::1512001600,reinhardt2006b

Support Vector Machine-Based Instantaneous Presence Detection for Continuous Wave Radar Systems - Schellenberger, Sven; Shi, Kilin; Steigleder, Tobias; Michler, Fabian; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (2018 Asia-Pacific Microwave Conference, 2018)
Instantaneous detection of missing vital signs at inpatient beds enables fast intervention for cardiac arrests. Using a 24 GHz bistatic radar, a fast presence detection based on a support vector machine (SVM) classifer is realized. Large body motions or even small distance deviations, such as movement of the chest induced by heartbeat or breathing, are distinguishable from the measured noise of an unoccupied bed. For classifcation two features are calculated based on windowed I and Q data. Performance is evaluated by varying window sizes from 0.2 ... 1.5 s for feature calculation and training of the SVM classifer. In the resting scenario an accuracy of 99.2% and F1-score of 99.1% with windows of 0.2 s is achieved. <br

Suppress Hysteresis by Means of Signal Conditioning - Jedlicska, Istvan; Weiß, Roland; Rieger, G.; Weigel, Robert (Sensor Conference, 2007)
elib2cris::1512001600,jedlicska2007

Suppression of spurious modes in mirror-type thin film BAW resonators using an appropriate shape of the active area - Link, Andreas; Schmidhammer, Edgar; Heinze, Habbo; Mayer, Markus; Schmiedgen, Monika; Bader, Bernhard; Wagner, Karl Christian; Weigel, Robert (IEEE Ultrasonics Symposium, 2005)
elib2cris::1512001600,link2005

Surface roughness and its structural orientation caused by internal microstructural changes in mechanically stressed copper conductors - Baron, Philipp; Lenz, Philipp; Schomer, Maria; Koch, Klaus Peter; Wittmann, Armin; Fischer, Georg (Journal of Materials Science, 2022)
In this paper, the mechanical damage behavior is investigated based on the characteristic roughness on the surface and the orientation of superficial structures. The main goal is to explore the surface roughness on mechanically loaded copper conductors as a lifetime indicator. For this purpose, copper conductors are mechanically stressed in accordance with EN 50,396 and then examined metallographically and microscopically. The microstructure examination shows that the roughness is caused by material extrusion and cracks due to work hardening in the surface area. Using confocal microscopy, it is shown for the first time that significant formation of surface roughness takes place over the service life of copper conductors. The roughness increases monotonically, but not linearly with number of cycles, due to internal microstructural processes and can be divided into three sections. First inspections of the conductor surface over lifetime show a correlation between the intensity of structures orientated 45° to the loading direction and the roughness. This phenomenon, already known from microscopic slip lines, is thus also evident in macroscopic roughness formation and is well founded by the research theory on material extrusion along dislocation lines. In summary, a lifetime determination is possible based on its developing roughness which enables the utilization as a sensor element.<br
Keywords: Copper; Conductors; Structural Analysis; Flow Figures; Slip Lines; Bending Stress

Surface velocity estimation of uids using millimetre-wave radar - Erhart, Christian; Lutz, Steffen; Köhler, Johannes; Mantz, Hubert; Walter, Thomas; Weigel, Robert (European Microwave Conference (EuMC), 2015)
This paper presents a microwave sensor which allows to measure the surface velocity of uids via determining the Doppler shift of the scattered signal. The design of the sensor follows a modular system. Thus the antenna as well as the ampli er can be exchanged easily. Measurements in industrial as well as in natural environments with di erent antennas will be shown. An extended focus will be on the development of a dielectrical waveguide antenna for near distance measurements in industrial environments. Dependency of the signal strength on the angle of polarisation will be investigated and an approach to estimate the velocity from the measured data will be introduced.
elib2cris::1512001600,erhart2015a

Surfing Virtual Waves to Thermal Tomography: From model- to deep learning-based reconstructions - Kovacs, Peter; Lehner, Bernhard; Thummerer, Gregor; Mayr, Guenther; Burgholzer, Peter; Huemer, Mario (IEEE Signal Processing Magazine, 2022)
Thermographic imaging is a fast and contactless way of inspecting material parts. Usually, with model-driven evaluation procedures, lateral heat flow is ignored, and, thus, 1D reconstruction is applied to detect defects. However, to correctly size defects, the lateral heat flow must be considered, which requires a full 3D reconstruction. The 3D thermal defect imaging is a major challenge because heat propagation is an irreversible process. The virtual wave concept (VWC) is a recently developed method that considers both lateral and axial heat flows and, therefore, allows multidimensional reconstruction at improved spatial resolution. This approach decomposes the problem into two steps; can be used for 1D, 2D, and 3D heat conduction problems; and provides new alternatives to using physical priors (e.g., nonnegativity and/or sparsity), all of which improve reconstruction accuracy at a relatively low computational cost.
CRIS-Team WoS Importer:2022-01-07

Switch Bootstrapping in a 1.5 Bit Pipeline Stage - Löhr, Robert; Ohnhäuser, Frank; Röber, Jürgen; Weigel, Robert (Analog2016, 2016)
The targeted 16 bit pipeline converter has an adjustable sampling frequency from 100MHz to 200MHz. In this paper the switches for the input and the reference voltage sampling are analyzed. Therefore, a novel switch bootstrapping technique is presented, which guarantees a worst case input voltage settling accuracy of LSB 2 at settling times between 2 ns to 5 ns. The non-linearity caused by the input switches is simulated and typically amounts to -115 dB. In addition a possible solution for external reference voltage settling is introduced.
elib2cris::1512001600,loehr2016
Keywords: 1.5 bit; switch bootstrapping; MDAC; charge injection; external reference; non-linearity

Switched-Mode Tuned Class E Power Amplifiers with Parallel Circuit - Grebennikov, Andrej; Jäger, Herbert; Weigel, Robert (Proc. Asia-Pacific Microwave Conference, 2002)
elib2cris::1512001600,grebennikov2002

Switching noise simulation on packages and on PCBs using PEEC and model order reduction techniques - Steinmair, Gernot; Katzier, H.; Weigel, Robert; Troescher, Matthias (15th International Zurich Sympoium & Technical Exhibition on Electromagnetic Compatibility (EMC 2003), 2003)
elib2cris::1512001600,steinmair2003

Switching Time Acceleration for High-Voltage CMOS RF Switch - Syroiezhin, Semen; Oezdamar, Oguzhan; Weigel, Robert; Solomko, Valentyn (ESSCIRC 2022 - IEEE 48th European Solid State Circuits Conference, Proceedings, 2022)
A high-voltage MOSFET-based RF switch with improved switching time is presented in this paper. The improvement is achieved by adding an auxiliary circuitry distributed along the stack which substantially speeds up the charging and discharging of gate oxide of the transistors. The auxiliary network is enabled by a delay-based control circuit defining acceleration time-window for switching transient. An RF switch comprising the proposed solution has been implemented in a dedicated 65 nm CMOS switch technology. The measured hardware demonstrates the improvement in switching time from 19.2 μ s to 1.6 μ s in OFF-to-ON direction and from 0.6 μ s to 0.2 μ s; in ON-to-OFF direction compared to the state-of-art implementation. The improvement is achieved at no penalty in key RF characteristics of the device. Particularly, both conventional and proposed switches are able to withstand up to 48 dBm RF power in OFF-state and demonstrate identical small- and large-signal response.
CRIS-Team Scopus Importer:2022-11-25
Keywords: Antenna tuning; cellular user equipment; fast switching; harmonics; high-voltage switch; switching speed; switching time acceleration

Symbol based statistical RF fingerprinting for fake base station identification - Ali, Arslan; Fischer, Georg (2019 29th International Conference Radioelektronika, RADIOELEKTRONIKA 2019 - Microwave and Radio Electronics Week, MAREW 2019, 2019)
The identification of fake base station (FBS) in a cellular network has become challenging with the development of various software defined radio platforms and mobile standards. This paper, therefore, presents robust statistical approach to detect unique non-linearities based hardware impairments of the transmitter. Employing the fact that power amplifier (PA) of a regular base station (RBS) is a costly and high precision device with a provision of sophisticated digital predistortion (DPD) hardware implementation and in contrary, this DPD based linearization effort is not spent in existing SDR platforms so PA of an SDR based FBS tends to violate the spectral mask and introduces large amplitude and phase errors in the transmitted signal compared to the RBS. At first, a second order symbol-based error vector magnitude (EVM) approach is triggered at the user equipment (UE) to measure the non-linearity induced by the PA of various SDR based FBS. Afterward, a higher fourth order moment i.e. kurtosis approach has been proposed along with the actual measurement results to determine the noise structuredness of the received signal at UE. The kurtosis on magnitude of extracted complex noise cloud is found to be a strong indicator to identify the FBS.
CRIS-Team Scopus Importer:2019-07-16
Keywords: Error vector statistics; Fake base station; Hardware impairments; Higher order moments; Kurtosis; Physical layer security; RF fingerprinting; Software defined radio

Symbol Based Statistical RF Fingerprinting for Fake Base Station Identification - Ali, Arslan; Fischer, Georg (29th International Conference Radioelektronika 2019, Microwave and Radio Electronics Week (MAREW), 2019)
The identification of fake base station (FBS) in a cellular network has become challenging with the development of various software defined radio platforms and mobile standards. This paper, therefore, presents robust statistical approach to detect unique non-linearities based hardware impairments of the transmitter. Employing the fact that power amplifier (PA) of a regular base station (RBS) is a costly and high precision device with a provision of sophisticated digital predistortion (DPD) hardware implementation and in contrary, this DPD based linearization effort is not spent in existing SDR platforms so PA of an SDR based FBS tends to violate the spectral mask and introduces large amplitude and phase errors in the transmitted signal compared to the RBS. At first, a second order symbol-based error vector magnitude (EVM) approach is triggered at the user equipment (UE) to measure the non-linearity induced by the PA of various SDR based FBS. Afterward, a higher fourth order moment i.e. kurtosis approach has been proposed along with the actual measurement results to determine the noise structuredness of the received signal at UE. The kurtosis on magnitude of extracted complex noise cloud is found to be a strong indicator to identify the FB
Keywords: higher order moments; error vector statistics; kurtosis; RF fingerprinting; fake base station; software defined radio; hardware impairments; physical layer security; Radio frequency; Fingerprint recognition; Base stations; Hardware; Signal to noise Ratio; Transmitters; Pluto

Symbol-by-Symbol and Trellis-Based Equalization with Widely Linear Processing for Space-Time Block-Coded Transmission over Frequency-Selective Fading Channels - Gerstacker, Wolfgang; Obernosterer, Frank; Schober, Robert; Lehmann, Alexander; Lampe, Alexander; Gunreben, Peter (Conference Proceedings, 2002)
In this paper, we develop receiver concepts for transmission with space-time block codes (STBC's) over frequency-selective fading channels. The focus lies on Alamouti's STBC, but the results may be generalized to related STBC's. We show that a straightforward combination of conventional equalizers and a space-time block decoder is only possible if at least as many receive antennas as transmit antennas are employed, but not for the practically interesting case of pure transmit diversity. This restriction is circumvented by our approach. Equalizers with widely linear (WL) processing are designed, utilizing the structural properties of the transmit signal of space-time block coding, which is shown to be improper (rotationally variant). These schemes are especially suited for equalization of high-level modulated signals, which are used in third-generation time-division multiple access mobile communications standards such as EDGE (Enhanced Data Rates for GSM Evolution).
UnivIS-Import:2015-04-16:Pub.2002.tech.IE.mobilk.symbol
Keywords: Frequency-selective fading channels; Block codes; Equalizers; Receiving antennas; Decoding; Transmitting antennas; Process design; Signal design; Signal processing; Mobile communication

Symbol Data Organization in a WB-CDMA Modem - Hein, Werner; Berkmann, Jens; Zimmermann, Markus; Huemer, Mario (European Conference on Wireless Technologies, 2007)
For a System-on-Chip (SoC) implementation of mass market devices like a wireless modem user equipment it is crucial -in addition to fulfilling the standardized functional requirements -to optimize both silicon die size and power dissipation. In current VLSI technologies at 65 nm and beneath, beside an optimized logic implementation, a careful dimensioning of all memories is a must. This applies especially to those synchronous random access memories (SRAM) which have to be built on-die because the data throughput is inevitable high like in the signal processing part of a modem's physical layer. This paper presents as an example for the receive path of a WB-CDMA modem a solution for a low power data organization of the frame-wise buffered symbol-streams in between demodulators and channel decoder. This solution is self-adapting in real time to the permanent changing data rates and volume respectively.
elib2cris::1512001600,hein2007
Keywords: VLSI technology; WB-CDMA modem; channel decoder; power dissipation; random access memory; symbol data organization; system-on-chip implementation; VLSI; broadband networks; code division multiple access; modems; system-on-chip

Synchronization approaches and improvements for a low-complexity power line communication system - Reißland, Torsten; Kuba, Matthias; Robert, Jörg; Koelpin, Alexander; Weigel, Robert; Lurz, Fabian (2019 IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids, SmartGridComm 2019, 2019)
This paper presents several improvements of the energy-pattern based sequence detection (EPSD) algorithm for FSK-based single-phase power line communication (PLC) systems, in terms of complexity, reliability and synchronization. A time synchronization is presented which fulfills the well known task of synchronizing transmitter and receiver, but also helps to avoid transmissions in periods of rough noise conditions. The synchronization method is based on a maximum-likelihood approach that makes use of the phase of the mains voltage. Further improvements concern the codes used for the trans-mitted sequences as well as the combination of the information within both FSK carrier-frequencies in terms of equal gain and maximum ratio combining. Additionally an approach for a low-complexity frame synchronization is presented.
CRIS-Team Scopus Importer:2019-12-24
Keywords: Fsk; Low-power; Plc; Wakeup receiver

Synthesis of Pulsed Frequency Modulated Ultra Wideband Radar Signals Based on Stepped Phase Shifting - Carlowitz, Christian; Eßwein, Alexander; Weigel, Robert; Vossiek, Martin (IEEE International Conference on Ultra-Wideband, ICUWB 2012, 2012)
The current paper introduces a novel concept for low complexity and low power synthesis of pulsed frequency modulated ultra wideband (PFM UWB) signals. Instead of using a VCO-based synthesizer, we employ a simple digitally tuned phase modulator that varies the phase of a high order harmonic of a fixed frequency LO signal. The phase modulated harmonic is then injected into a switched injection locked pulse oscillator. Based on this concept, an arbitrary sequence of phase samples i.e. UWB pulses where each pulse has a predefined carrier phase can be generated. This sampled pulse sequence can be used for the generation of angle modulation schemes for communication signals and also for the generation of pulsed linear frequency modulated radar signals. The capability of the proposed concept is experimentally demonstrated for the synthesis of 6 to 8 GHz UWB pulsed frequency sweeps. Measurement results verify that this novel approach delivers a performance comparable to much more complex pulsed frequency modulation implementations. © 2012 IEEE.
UnivIS-Import:2015-04-16:Pub.2012.tech.IE.LEH.synthe
Keywords: Injection locked oscillators; radar; signal sampling; transponders; ultra wideband technology

Synthesizer concepts for FMCW based locatable wireless sensor nodes - Ußmüller, Thomas; Jung, Melanie; Weigel, Robert (Wireless Sensing, Local Positioning, and RFID, 2009. IMWS 2009. IEEE MTT-S International Microwave Workshop, 2009)
Local positioning systems significantly enhance the value of wireless sensor networks (WSN). This paper first motivates the use of WSN with exemplary application scenarios. Afterwards it shortly addresses the basics of frequency modulated continuous wave (FMCW) systems. Several common synthesizer concepts for FMCW radars are shown. The paper focuses on a novel integrated synthesizer for localization using frequency modulated continuous wave (FMCW) radar. The synthesizer is based on a fractional-n phase-locked loop (PLL) architecture. All components of the PLL are carefully designed with respect to their performance and power consumption. The complete synthesizer was manufactured in a 0.18 mum SiGe BiCMOS process from IBM, and it draws only 39 mA from the supply. It achieves a phase noise better than -113 dBc/Hz and has a silicon area of 1.15 mm2. Due to its high integration level and its optimized design, the synthesizer achieves low power consumption and low phase noise that makes it suitable for precise localization in mobile sensor nodes. Localization measurements in indoor environments with multipath propagation showed mean distance errors about 13 cm.
elib2cris::1512001600,ussmueller2009d
Keywords: BiCMOS integrated circuits; CW radar; FW radar; frequency synthesizers; phase locked loops; radio direction-finding

Synthesizer for FMCW based Localization inWireless Sensor Networks - Ußmüller, Thomas; Jung, Melanie; Weigel, Robert (IEEE International Conference on Wireless Information Technology and Systems, Workshop on Innovative Circuits, Systems and Applications for Local Position Estimation, 2010)
elib2cris::1512001600,ussmueller2010a

System Analyses of Class-S Power Amplifier - Samulak, Andrzej (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)

System Analysis of a Phased-Array Radar Applying Adaptive Beam-Control for Future Automotive Safety Applications - Dudek, Manuel; Nasr, Ismail; Bozsik, Gabor Josef; Hamouda, Mohammed; Kissinger, Dietmar; Fischer, Georg (IEEE Transactions on Vehicular Technology, 2015)
elib2cris::1512001600,dudek2015

System and Circuit Integration Techniques for GSM and UMTS Mobiles - Weigel, Robert (Asia-Pacific Microwave Conference Workshop on RF Technologies for Wireless Terminals, 2002)
elib2cris::1512001600,weigel2002e

System and Signal Design for an Energy-efficient Multi-frequency Localization System - Nowak, Thorsten; Hierold, Martin; Kölpin, Alexander; Hartmann, Markus; Tröger, Hans-Martin; Thielecke, Jörn (IEEE Topical Conference on Wireless Sensors and Sensor Networks, 2014)
In this paper a concept for an energy-efficient multi-frequency localization system is proposed. The system design aims at extremely light-weight, and thus energy-efficient tags. The localization system is realized by a Wireless Sensor Network comprising signal strength and phase measurements. The concept is based on signals for phase-based ranging. The proposed signals have to meet several constraints: low-power signal generation, efficient signal pro-cessing, and, most important, precise range estimation. The performance of the range estimation is assessed utilizing the Cramér-Rao Lower Bound. © 2014 IEEE.
UnivIS-Import:2015-04-16:Pub.2014.tech.IE.komele.system
Keywords: localization; multi-frequency; phase-based ranging; Wireless sensor network

System Approaches and QoS Aspects for FMCW Radar Localisation - Mosshammer, Ralf (EEEfCOM, 2008)
elib2cris::1512001600,mosshammer2008a

System Archictecture for Hybrid Communication and Localization in Downlink LTE - El Assaad, Ahmad; Fischer, Georg (Hybride Kommunikations- und Ortungstechnologien für das vernetzte Fahren – Technologiestand und Ausbaupotenzial, DGON-Konvent 2017, 2017)

System architectures and circuit techniques for integrated RF transceivers for UWB localization and sensing - Dufrene, Krzysztof; Hartmann, Marcus; Weigel, Robert (Unspecified, 2006)
elib2cris::1512001600,dufrene2006a

Systemaspekte im Umfeld der Analog-Digital Balance von Transceivern - Fischer, Georg (Electrical and Electronic Engineering for Communication Workshop - Entwicklerforum - Fachmesse, 2012)
elib2cris::1512001600,fischer2012a

Systematic Experimental fT and fmax Comparison of 40-nm Bulk CMOS versus 45-nm SOI Technology - Rimmelspacher, Johannes; Werthof, A.; Weigel, Robert; Issakov, V. (EuMIC 2019 - 2019 14th European Microwave Integrated Circuits Conference, 2019)
The unity current gain frequency (fT) and the maximum oscillation frequency (fmax) are key parameters used to characterize the highest achievable speed of a semiconductor technology. However, there is typically a high uncertainty level concerning evaluation of these values, related to several factors. First, these metrics are obtained from small-signal transistor measurements at low gigahertz frequencies and extrapolated far to a range of several hundreds of gigahertz. Hence, a large deviation of obtained values is possible, depending on the point at which the extrapolation is taken. Second, depending on metallization layer down to which the transistor interconnect parasitics are de-embedded, the value of fmax may vary significantly. Therefore, it is a challenge to compare technologies in a fair and consistent way by means of reported fT and fmaxvalues, since these values could have been obtained for strongly differencing conditions. This paper presents a systematic comparison of fT and fmax values for two technologies: 40 nm bulk CMOS and 45 nm RF silicon-on-insulator (RF-SOI) CMOS. The values are obtained experimentally from S-parameter measurements under rigorously similar conditions for both technologies. We use the same extrapolation frequencies and de-embed the results down to the same metal level using the same de-embedding technique and similar structures. Finally, we discuss the results and provide additional insights.
CRIS-Team Scopus Importer:2019-12-24
Keywords: CMOS; de-embedding; millimeter-wave

Systematic Performance Evaluation of a Novel Optimized Differential Localization Method for Capsule Endoscopes - Zeising, Samuel; Ararat, Kivanc; Thalmayer, Angelika; Anzai, Daisuke; Fischer, Georg; Kirchner, Jens (Sensors, 2021)

System Capacity Analysis for High-Precision Radiolocation in the 5.8 GHz ISM Band - Mosshammer, Ralf; Huemer, Mario; Weigel, Robert (IEEE 69th Vehicular Technology Conference 2009 (VTC Spring 2009, 2009)
Quality of Service (QoS) is a prevalent issue in communication systems, but an often neglected aspect of local positioning. In this paper, we present a QoS architecture for the high-accuracy local positioning system RESOLUTION. Different backend configurations of this system are compared in terms of impact on accuracy and latency of the system. Quality metrics relevant to local positioning requirements are defined and tested with several protocol and algorithmic options by means of simulations. Results indicate parameter tradeoffs which call for optimization of the backend architecture for specific deployment scenarios. These insights are easy to transfer to any positioning system which has to deal with channel contention situations.
elib2cris::1512001600,mosshammer2009c
Keywords: Bandwidth; indoor communication; CW radar; FM radar

SystemC Modeling of GSM/UMTS Baseband Architectures for Rapid Simulation of Multimedia Applications - Huemer, Mario; Fuerreder, A.; Troebinger, C.; Eidenberger, E.; Eibensteiner, F.; Dietl, H.; Heigl, H.; Margiol, H.; Lüftner, Thomas (International Symposium on Signals, Systems and Electronics, 2004)
elib2cris::1512001600,huemer2004a

SystemC Modelling and Simulation of Highly Integrated Baseband ICs for 2.5th Generation Mobile Phones - Huemer, Mario; Bichler, Daniel; Dorfmair, Wolfgang; Knauseder, Roman; Osterkorn, Christian; Lüftner, Thomas (Austrochip 2003, 2003)
The dramatical increase of chipinternal data traffic in baseband processors for multimediaoriented mobile phones or PDAs requires highly sophisticated tools and simulation platforms, which allow to model and optimize the overall chip architecture in a convenient way. In this contribution we present a SystemC based simulation platform, which represents a basic and easy extensible model for simulation and optimization of FIFO buffer sizes, clock, bus and DMAconcepts. We briefly present the basic system model, the implementation with SystemC, and we also present simulation results of a simple test scenario.
elib2cris::1512001600,huemer2003a
Keywords: SystemC; 2.5G

System Considerations and RF Front-End Design for Integration of Satellite Navigation and Mobile Standards - Miskiewicz, Anna; Weigel, Robert; Holm, Andreas (Kleinheubacher Tagung, 2008)
elib2cris::1512001600,miskiewicz2008a

System-Defined Design and Performance of RFICs for W-CDMA Mobile Radio Terminals - Maurer, Linus; Lanschützer, Christian; Springer, Andreas; Weigel, Robert (Elektrotechnik und Informationstechnik, 2001)
Third generation wideband CDMA (W-CDMA) systems like UMTS will add broadband data to support video, Intemet access, and other high speed services for untethered devices. They are currently deployed in Japan and will be introduced in Europe in 2002. Despite sufficient RF performance has been assumed in the standardization bodies, especially in mobile devices the RF part is still a limiting factor for the overall system characteristics. Only an integral design approach including both RF and baseband functionalities makes it possible to achieve analog front-ends with sufficient performance. This paper reviews transceiver architectures with respect to W-CDMA and presents some of the recent silicon-based radio frequency integrated circuits for mobile terminals.
elib2cris::1512001600,maurer2001
Keywords: RFIC; transceivers; radio communication; CDMA; UMTS

Systemdesign eines Dualband-Multimode Wireless LAN-HF-Transceivers - Pimingsdorfer, Dieter (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2007)

System Design for Encounter Detection of Distributed Wireless Sensors - Hierold, Martin; Ripperger, Simon; Mayer, Frieder; Weigel, Robert; Kölpin, Alexander (German Microwave Conference 2015 (Gemic), 2015)
In this paper a system for proximity detection of small sized animals like bats is presented. The system is based on a time slotted communication between compact low weight mobile nodes. For precise time synchronization of the nodes a scalable grid of base stations is proposed that distributes a time reference signal using a time division multiple access (TDMA) scheme. The system parameters are chosen considering the timing constraints caused by the severe requirements to the mobile nodes. In a power consumption analysis the system operation time limited by the 1.8 g nodes is calculated to be 8.3 days. First field test results are shown which proof the functional capability of the system's principle.
elib2cris::1512001600,hierold2015a
Keywords: wireless sensor network; low power

System Design Impacts on Battery Runtime of Wearable Medical Sensors - Tobola, Andreas; Korpok, Oliver; Leutheuser, Heike; Schmitz, Björn; Hofmann, Christian; Struck, Matthias; Weigand, Christian; Eskofier, Björn; Heuberger, Albert; Fischer, Georg (Mobile and Information Technologies in Medicine and Health, Proceedings (MobileMed), 2014, 2014)
UnivIS-Import:2015-04-16:Pub.2014.tech.IMMD.IMMD5.system

System Design of a 77 GHz Automotive Radar Sensor with Superresolution DOA Estimation - Wenig, Peter; Schoor, Michael; Günther, Oliver; Yang, Bin; Weigel, Robert (International Symposium on Signals, Systems and Electronics, 2007. ISSSE '07, 2007)
This paper introduces a novel 77 GHz FMCW automotive long range radar (LRR) system concept. High resolution direction of arrival (DOA) estimation is an important requirement for the application in automotive safety systems. The challenges in system design regarding low cost and superresolution signal processing are discussed. Dominant interferences to the MUSIC DOA estimator are amplitude and phase mismatches due to inhomogeneous antenna patterns. System simulation results deliver design guidelines for the required signal-to-noise ratio (SNR) and the antenna design. Road traffic measurements with a demonstrator system show superior DOA resolution and demonstrate the feasibility of the design goals.
elib2cris::1512001600,wenig2007a

Systemgrenzen und Fehlerkompensationsstrategien der Sechstormesstechnik im industriellen Kontext - Lindner, Stefan (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2017)
Die sechstorbasierte Empfängerarchitektur ist bereits seit den siebziger Jahren bekannt und erlangte in den vergangenen Jahren weltweit wieder vermehrt die Aufmerksamkeit verschiedener Forschungsgruppen. Dies liegt zum einen darin begründet, dass die Implementierung der Technologie in dem für neue Anwendungen oft verwendeten Frequenzbereich oberhalb von 10 GHz einfach möglich ist, und zum anderen daran, dass das hohe Phasenauflösungsvermögen dieser Architektur bereits vielfach gezeigt werden konnte. Durch diese Eigenschaften eignet sich die Sechstortechnik besonders für das sich in Entwicklung befindliche Feld der mikrowellenbasierten industriellen Sensorik, für das günstige Sensoren mit kleinen Bauformen benötigt werden, an die hohe Anforderungen bezüglich Genauigkeit und Latenz gestellt werden. Inwieweit das Sechstor dazu geeignet ist, soll der Untersuchungsgegenstand dieser Abhandlung sein. Nach einer Einführung in die Funktionsweise der Architektur folgt zu diesem Zweck ein Vergleich, um die Vorteile des additiven Mischansatzes der Sechstortechnologie gegenüber einem ebenfalls passiven, jedoch multiplikativen Mischer zu zeigen. Anschließend werden für die industrielle Sensorik wichtige Messaufgaben, wie die Frequenzmessung, die hochgenaue Abstandsmessung sowie die Vibrationsanalyse und deren jeweilige Implementierungen mit der Sechstorarchitektur, eingeführt. Basierend auf diesen Anwendungen folgt im Anschluss ein umfangreiches Kapitel, in dem die Systemauslegung sowie die Systemgrenzen auf theoretischer Basis und anhand von Simulationen analysiert werden. Es wird gezeigt, dass viele der Störeinflüsse durch entsprechende Kompensationsstrategien unterdrückt werden können, um die Messunsicherheit zu verringern. Außerdem werden für die Abstands- und Frequenzmessung dedizierte Linearisierungsverfahren, die im Rahmen dieser Arbeit entwickelt wurden, dargestellt. Besonders für das ebenfalls vorgestellte Mehrtonverfahren, das die Erweiterung des eindeutigen Messbereichs ermöglicht, ist eine effektive Unterdrückung von Nichtidealitäten durch diese Linearisierungsverfahren nötig. Um die Realisierbarkeit der dargestellten Anwendungen zu zeigen, werden ausgewählte Demonstratoren und deren Ergebnisse vorgestellt. Diese zeigen für die Abstandsmessung Genauigkeiten von wenigen Mikrometern und für die Frequenzmessung einen relativen Fehler weniger Millionstel (parts per million, ppm). Darüber hinaus wird auch ein erster Prototyp und dessen optimierter Entwicklungsprozess für einen industriellen Abstandssensor gezeigt, der auf der Sechstortechnik beruht und eine erste kommerzielle Realisierung dieser Technik für die Abstandsmessung darstellt.
Keywords: Six-port; Sechstor; Radar; Nahbereich; Short-range-radar; FSK; ISM; Frequenzmessung

Systemkonzept eines autarken und intelligenten Miniatur-Sensors für Smart Home - Schuklin, Dennis; Hohnloser, Daniel; Lieske, Tobias; Reichenbach, Marc; Bänisch, Andreas; Pfundt, Benjamin; Röber, Jürgen; Weigel, Robert; Fey, Dietmar (VDE Kongress 2016: Internet der Dinge, 2016)
Trotz der erheblichen Fortschritte im Bereich Smart Home, stellt die Installation von Hunderten von Sensoren eine der größten Herausforderungen dar. Eine mögliche Lösung für dieses Problem ist die Integration aller Komponenten innerhalb einer integrierten Schaltung. Dieser Beitrag stellt ein Konzept für ein intelligentes Sensorsystem dar, welches die wichtigsten Sensoren für das intelligente Zuhause (wie z.B. Drucksensor, Gassensor, Temperatur-, oder Lichtsensor) auf einem Chip vereint. Dadurch wird das Messen von lokalen Temperaturen, Lichtverhältnissen, Drucks und sogar Luftqualität ermöglicht. Mit diesen umfassenden Informationen können lebensunterstützende Systeme, Einbruchsdetektion, automatisierte Klimaregelung und Beleuchtungssteuerung in Räumen und vieles mehr realisiert werden. Langfristiges Ziel dieser Arbeit ist die Entwicklung eines selbst organisierenden und autonomen Netzwerks von intelligenten Sensoren im Bereich Smart Home. Mit Abmessungen von wenigen Zentimetern, kann jeder Sensor nahezu überall angebracht werden, wie zum Beispiel an einem Fenster.
elib2cris::1512001600,shuklin2016
Keywords: Smart Home; Intelligent Sensor System; MEMS Sensor; Analog to Digital Converter; Digital Processing Unit

Systemkonzept für Front-End und Frequenzsynthese im Kontext von breitbandiger Funküberwachung - Mzyk, Raphael (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2013)

Systemsimulation des analogen und digitalen Frontends für rekonfiguierbare Multistandard-Mobilfunkempfänger - Chabrak, Karim (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2006)

System Simulation of a 79 GHz UWB-Pulse Radar Transceiver Front-End for Automotive Applications - Sewiolo, Benjamin; Hartmann, Marcus; Günther, Oliver; Weigel, Robert (Institut für Mobil- und Satellitenfunktechnik - UWB2006, 2006)
An UWB-Pulse radar transceiver front-end at 79 GHz with 4 GHz bandwidth was simulated, both to see the differences between existing 24 GHz systems and to configure the transceiver performance for the hardware development at 79 GHz in SiGe bipolar technology. Initial values were taken from former 24 GHz publications like [1] and were adjusted to the requirements at the higher frequency range. The simulation includes the validation of the basic system parameters of the radar system, the ability to get the distance and velocity information of detected objects in a specified range and the implementation of the hf-parameters like noise, linearity and isolation. This will make it possible to get an overview of the circuit non-idealities of the specific
elib2cris::1512001600,sewiolo2006

System topologies and performance evaluation of the RESOLUTION embedded local positioning system - Mosshammer, Ralf; Eickhoff, Ralf; Huemer, Mario; Weigel, Robert (Elektrotechnik und Informationstechnik, 2008)
This article introduces a hybrid communications and positioning system, developed in the course of the EU-endorsed RESOLUTION project. The system provides a reconfigurable, embedded hardware platform fit to support a variety of deployment scenarios. The flexibility of our solution is assessed by means of a comprehensive system simulation.
elib2cris::1512001600,mosshammer2008

System- und Schaltungskonzepte für Low-Power-Radarsensorik zur Anwesenheitsdetektion - Lurz, Fabian; Mann, Sebastian; Linz, Sarah; Lindner, Stefan; Weigel, Robert; Kölpin, Alexander (Mikrosystemtechnik-Kongress (MST), 2015)
elib2cris::1512001600,lurz2015b

Tag, you're it - Costanzo, A.; Masotti, D.; Ußmüller, Thomas; Weigel, Robert (IEEE Microwave Magazine, 2013)
elib2cris::1512001600,costanzo2013

Target Recovery from Randomly Distributed Radars using Compressed Sensing Techniques - Reißland, Torsten; Kölpin, Alexander; Weigel, Robert (Kleinheubacher Tagung, 2017)
In highly automated industrial applications radar sensor systems already play an important role. For future applications, good knowledge about the three-dimensional environment of physically acting industrial systems will be beneficial, if not necessary. For this reason, the use of distributed radar systems to gain precise knowledge of the systems environment and its work pieces is proposed. In the literature only few approaches for three-dimensional radar target recovery in the short range can be found. Furthermore, these approaches presume different kinds of regular patterns in which the radar sensors must be placed. This is obviously contrary to the requirements of e.g. industrial robots which can be moved on arbitrary trajectories. The most challenging problem when it comes to target recovery from randomly distributed radar sensors is the high computational effort which has to be spent. In this work an algorithm is presented which aims at recovering several point targets from as few as possible radar measurements. The whole work is based on simulations and analytical considerations. Each radar uses well-known frequency modulated continuous waveform signals to gain information in range direction. As stated in the title the recovering is carried out by a compressed sensing algorithm. To use this algorithm the whole problem has to be transformed into a linear system of equations, small enough to be solved by commercially available computers in an amount of time which is suited for the application. This linear equation eventually consists of the received radar signals, a measurement matrix and the reflectivity of assumed targets located in a-priori defined voxels. As the number of voxels which have to be taken into account increases drastically with the desired resolution, an iterative approach had to be developed to limit the algorithms requirements in terms of computational effort. Finally, different suited recovery algorithms were compared in terms of robustness.
Keywords: Radar; Compressed Sensing; Imaging

Target Simulator concept for Chirp Modulated 77 GHz Automotive Radar Sensors - Lutz, Steffen; Walter, Thomas; Weigel, Robert (European Radar Conference, 2014)
elib2cris::1512001600,lutz2014a

TCDMA: A New Multiple Access Technology for Indoor Wireless Communications - Zhang, Zhongping; Seifert, Franz; Weigel, Robert (Proc. European Symposium on Advanced Networks and Services. Broadband networks: Strategies and Technologies, 1995)
elib2cris::1512001600,zhang1995a

TCDMA: Systemmodellierung, -simulation und -implementation - Zenzinger, Alesander; Zhang, Zhongping; Seifert, Franz; Weigel, Robert (Proc Kleinheubacher URSI/ITG-Tagung, 1996)
elib2cris::1512001600,zenzinger1996a

Techniques for Reconfigurable Integrated Power Amplifiers with RF Switches - Rascher, Jochen; Zohny, Amr; Weigel, Robert (Electric and Electronic Engineering for Communication Workshop (EEEfCOM), 2012)
elib2cris::1512001600,rascher2012a

Technologien integrierter Leistungsmosfets - Dornberger, Barbara (RADCOM 2013, 2013)
elib2cris::1512001600,dornberger2013

Technologies for RFID sensors and sensor tags - Ußmüller, Thomas; Hagelauer, Amelie Marietta; Weigel, Robert (Cambridge University Press, 2014)
elib2cris::1512001600,ussmueller2014

Technologies for the Evolution of the RF System with a Base Station - Fischer, Georg (Bell Labs Mini Summit, 2006)
elib2cris::1512001600,fischer2006

Telemedicine at the example of sensor implants - Walk, Jasmin; Ußmüller, Thomas; Weigel, Robert; Fischer, Georg (IEEE Radio and Wireless Symposium (RWS), 2012)
In recent years, much research has been devoted to the improvement of telemedicine. As an introduction of the workshop the first talk will review the basics of telemedicine and medical sensor applications. Central challenges and several system concepts will be introduced and their pros and cons will be discussed. Favorable health care needs completely imperceptible and maintenance free sensor devices. Especially long term monitoring sensors have to meet this requirement. A promising solution is an implantable sensor system. The permittivity of body tissue and the desired distance to a remote station confronts the technology with several challenges. In addition a local data platform will be presented, which has to realize the interaction between sensors and a cellular network.
elib2cris::1512001600,walk2012

Temperature Calibration of a Differential Pair based Direct Digital Synthesizer through Subsampling Spectral Analysis - Lämmle, Benjamin; Wagner, Christoph; Jäger, Herbert; Weigel, Robert (Topical Meeting on Silicon Monolithic Integrated Systems in RF Systems, 2010)
The temperature behavior of a high speed direct digital synthesizer with a maximum clock frequency of 16.8 GHz and a power consumption of 488 mW at room temperature is investigated. The DDS has been manufactured in a 200-GHz ft SiGe bipolar technology and occupies a chip area of 1.15 mm2. A subsampling approach is introduced to analyze the output spectrum of the DDS. A calibration is performed over temperature to improve the spectral performance of the DDS. The calibration is based on a two point measurement and the use of a look-up table. After calibration, the third harmonic is below 53 dBc and a narrow band SFDR is nearly constant at 38 dBc.
elib2cris::1512001600,laemmle2010

Test Method for Contactless On-wafer MEMS Characterization and Production Monitoring - Linz, Sarah; Oesterle, Florian; Lindner, Stefan; Mann, Sebastian; Weigel, Robert; Kölpin, Alexander (IEEE Transactions on Microwave Theory and Techniques, 2016)
elib2cris::1512001600,linz2016

Test of alternative LTCC manufacturing processes for HF applications with realistic modeling of thick film technologies - Talai, Armin; Donati, Giovanni; Weigel, Robert; Kölpin, Alexander (TuZ 2014 Testmethoden und Zuverlässigkeit von Schaltungen und Systemen, 2014)
elib2cris::1512001600,talai2014c

The advantages of a known sequence versus cyclic prefix in a SC/FDE system - Witschnig, Harald; Mayer, Thomas; Springer, Andreas; Koppler, Alois; Maurer, Linus; Huemer, Mario; Weigel, Robert (International Symposium on Wireless Personal Multimedia Communications, 2002)
In this work we investigate the advantages of a known symbol sequence - a so-called unique word (UW) - instead of the well-known cyclic prefix (as is used in OFDM systems) for a single carrier system with frequency domain equalization (SC/FDE). The concept of UW fulfills the theorem of cyclic convolution - required to implement an efficient equalization for the SC/FDE structure. We elaborate on the advantages that result for decision feedback equalization (DFE) in detail. It is shown that a DFE based on the concept of UW shows significant advantages in comparison to a traditional time domain DFE or a DFE based on cyclic prefix. Simulation results confirm the theoretical advantages.
elib2cris::1512001600,witschnig2002c
Keywords: WLAN; OFDM; UW; DFE; SC/FDE

The Advantages of a Unique Word for Synchronisation and Channel Estimation in a SC/FDE System - Witschnig, Harald; Mayer, Thomas; Petit, M.; Hutzelmann, Holger; Springer, Andreas; Weigel, Robert (5th European Personal Mobile Communications Conference, 2003)
elib2cris::1512001600,witschnig2003

The Boolean Determinant Calculus - Can, Yavuz (DYNAMIC CONTROL AND OPTIMIZATION, DCO 2021, 2022)
CRIS-Team WoS Importer:2023-05-26

The Development of a Biocompatible Testbed for Molecular Communication with Magnetic Nanoparticles - Bartunik, Max; Fischer, Georg; Kirchner, Jens (IEEE Transactions on Molecular, Biological and Multi-Scale Communications, 2023)
Although the concept of engineered molecular communication has been around for quite some time, practical approaches with truly biocompatible setups are still scarce. However, molecular communication has a large potential in future medical applications and may be a solution to size constraints of antenna-based transmission systems. In this work, we therefore present a testbed using biocompatible magnetic nanoparticles. Based on previous work, all testbed components have been improved regarding performance and size, making a large step forward regarding miniaturisation and a data transmission approach. In addition, a setup for localised two-dimensional sensing of magnetic nanoparticles is presented. All improvements are evaluated individually and combined to achieve a net data rate of more than 6, significantly higher than any other comparable biocompatible setu
Keywords: molecular communication; biocompatible; magnetic nanoparticles; testbed

The effect of blockwise transmission on higher-order modulation schemes for SC/FDE - Witschnig, Harald; Oßberger, Gerald; Springer, Andreas; Koppler, Alois; Maurer, Linus; Huemer, Mario; Weigel, Robert (International Symposium on Wireless Personal Multimedia Communications, 2002)
Witschnig, H. ; Ossberger, G. ; Springer, A. ; Koppler, A. ; Maurer, L. ; Huemer, M. ; Weigel, R. ;
elib2cris::1512001600,witschnig2002b
Keywords: WLAN; UW; OFDM; DFE; SC/FDE

The Enhanced Six-Port Architecture: A Measurement Based Proof of Concept - Kölpin, Alexander; Lindner, Stefan; Vinci, Gabor; Lämmle, Benjamin; Weigel, Robert (IEEE Topical Meeting on Wireless Sensors and Sensor Networks, 2012)
In this publication the concept of the enhanced six-port receiver is proven by measurements of a hardware demonstrator. The enhanced six-port architecture has been proposed for simultaneous data reception and angle of arrival estimation with only one receiver front-end. It offers high positioning accuracy and high bandwidth combined with low circuit complexity. Up to now the concept has only been introduced and validated by system simulations. In this publication measurements of a hardware setup will be presented for the first time proving the functionality and performance of this new and promising architecture.
elib2cris::1512001600,koelpin2012
Keywords: enhanced six-port; microwave circuit

The enhanced six-port receiver: A new concept for simultaneous data reception and direction of arrival detection - Kölpin, Alexander; Vinci, Gabor; Lämmle, Benjamin; Weigel, Robert (International Microwave Symposium 2011, 2011)
The key benefits of the six-port receiver architecture, being a special type of direct conversion receivers, are its high bandwidth and low circuit complexity. This concept has been known on the one hand for precise phase measurement applications and on the other hand for complex valued data reception in the millimeter wave region. The work presented here shows a new approach for combining both principles in one six-port receiver. For the first time a method for simultaneous data reception and direction of arrival (DOA) detection will be presented requiring only one enhanced six-port front-end.
elib2cris::1512001600,koelpin2011
Keywords: Ad hoc networks; Antennas; Equations; Microwave Circuits; Microwave Communication; Receivers; Direction of arrival; Six-Port

The First Cell Phone in Molecular Communications: A Pilot Model of a Biological Transmitter - Grebenstein, Laura; Kirchner, Jens; Stavracakis Peixoto, Renata; Fischer, Georg; Weigel, Robert; Schober, Robert; Burkovski, Andreas (3rd Workshop on Molecular Comunications, 2018)
In the past years, Molecular Communications were studied mainly from a communication engineering and theoretical point of view. To design nano- to micro-sized signaling networks, reliable communication-theoretical models and experimental testbeds are still missing. Inspired by microbial cells we established an organic, molecular signal converter as a modulator for MC signals. The transmitter is a bacterial cell expressing the light-driven proton pump gloeorhodopsin. In recent test runs, we were able to send short messages encoded in a light signal and converted to pH variation with a rate of 2 bits/min with the help of living bacteria.<br

The Impact of Antenna Characteristics on Target Signal Detection in FMCW-Radar System Simulations for Automotive Applications - Dudek, Manuel; Nasr, Ismail; Kissinger, Dietmar; Weigel, Robert; Fischer, Georg (IEEE Radio Wireless Symposium (RWS), 2012)
In this scientific paper a versatile system simulation environment is introduced that enables investigations on millimeter-wave FMCW-radar sensors. With respect to the latest developments in automotive radar the simulator combines an RF-frontend simulation engine and a 3D ray-tracing tool to take the effects of the radar channel into account. Furthermore different antenna characteristics can be generated by the phased-array radar topology implemented to examine not only the behavior of the RF-frontend but the impact of the concrete traffic situation on the whole sensor system. Therefore development engineers are actively assisted with their task to design new accurate and reliable systems, thus enabling the transition from current pure comfort systems to future systems including an increased number of safety functions. To demon-strate the usability of this advanced simulation approach for the development of future radar sensors a typical traffic scenario is calculated showing not only the impact of the antennas’ beamwidth and side-lobes on target signal detection, but also the performance of the simulation environment built-up.
elib2cris::1512001600,dudek2012

The impact of embedded wafer level BGA package on the antenna hemispherical lens characterization for wireless applications at 61 GHz - Pour Mousavi, Seyed Mehran; Wojnowski, Maciej; Roehr, S.; Sommer, Grit; Weigel, Robert (European Conference of Antennas and Propagation (EuCAP), 2013)
elib2cris::1512001600,pourmousavi2013

The Impact of embedded wafer level BGA Package on the Antenna Performance - Pour Mousavi, Seyed Mehran; Wojnowski, Maciej; Agethen, Roman; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2013)
elib2cris::1512001600,pourmousavi2013a

The Impact of Phase Noise Parameters on Target Signal Detection in FMCW-Radar System Simulations for Automotive Applications - Dudek, Manuel; Nasr, Ismail; Kissinger, Dietmar; Weigel, Robert; Fischer, Georg (CIE International Conference on Radar, 2011)
Accurate system simulations have proven to be a valuable aid during the development process and help to decrease the time-to-market and the amount of design iterations, thus keeping development costs at a moderate level. Therefore a frequency-modulated continuous-wave (FMCW) radar system simulation environment has been built up, enabling for performance analysis of millimeter-wave radar frontends for automotive applications. A key parameter especially for radar systems applying the FMCW principle thereby is the linearity of the frequency ramp as it directly affects the quality of the target signal and thus the performance of the entire radar sensor. Hence in this scientific paper we investigate the influence of a phase noise afflicted VCO on the target signal detection, and the range resolution respectively. Leeson’s equation is applied to model oscillator phase noise and the results show which parameters are crucial for the radar system. Eventually a two-target scenario is calculated to substantiate the statements taken.
elib2cris::1512001600,dudek2011b

The impact of the material distribution of porousified LTCC on the effective permittivity investigated by finite 3D field simulation - Steinhäußer, Frank; Talai, Armin; Kölpin, Alexander; Weigel, Robert; Bittner, Achim; Schmid, Ulrich (Mikrosystemtechnik-Kongress (MST), 2013)
Apart from other advantages, such as its robustness, the high permittivity of LTCC (Low Temperature Cofired Ceramics) multi layer technology is one of the most important reasons why it is nowadays well established in high frequency devices and systems. However, reduced emission is not desired in every application. Antennas require a substrate with a low permittivity in order to achieve maximum emitter efficiencies. The chemical composition of LTCC allows the local introduction of air by means of a selective etch process. Due to this selective and diffusion controlled process the generated porousification is not homogeneous depending on the penetration depth. On the basis of measured lateral material distributions, the effect on the effective permittivity can be shown by performing 3D field simulations. The distributions are graphically derived from material cuts, which were realized by focused ion beam technology. From the complex trends, conclusion regarding the alteration of the inner chemical phase distribution as well as the quality and the bearing capability of the surface can be obtained.
elib2cris::1512001600,steinhaeusser2013

The Influence by Trapezoidal Conductor Shapes on Ring-Resonator based Material Characterization up to 110 GHz - Talai, Armin; Steinhäußer, Frank; Bittner, Achim; Schmid, Ulrich; Weigel, Robert; Kölpin, Alexander (International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications, 2014)
Material characterization by ring-resonator based measurements is well established since the early 20th century. Since then, the demand on spectral complex permittivity characterizations of RF materials and dielectric covers at higher microwave frequencies rises. Nowadays, both free space applications, e.g. 77 GHz automotive radar systems, and dielectrics for microchip packages require accurate knowledge of the relative permittivity in order to optimize RF circuit designs. With increasing frequencies, the conductor shape of photochemically etched ring-resonators gets more influence on the effective ring radius, and therefore the measured resonance frequencies, which results in an error for the relative permittivity determination. This paper provides correction factors for the ring radii up to 110GHz, compensating the altered field distribution due to trapezoidal edges.
elib2cris::1512001600,talai2014a
Keywords: CAD Modeling; Effective Permittivity; Field Simulation; material characterization; Microstrip Structure; Ring-Resonator; Trapezoidal Conductor