Passive RFID Transponders at UHF Frequencies: A Technical Overview - Heidrich, Jürgen; Weigel, Robert (EEEfCOM, 2008)
elib2cris::1512001600,heidrich2008

Penta-Band Inverted-F Antenna Tuned by High-Voltage Switchable RF Capacitors - Solomko, Valentyn; Özdamar, Oguzhan; Weigel, Robert; Hagelauer, Amelie (IEEE Open Journal of Antennas and Propagation, 2021)
A penta-band inverted-F antenna (IFA) tuned by two high-voltage aperture tuning networks is presented in the paper. The design is based on a singe, non-bended radiating arm IFA. Each of the two aperture tuners comprises a high-voltage switchable RF capacitor IC in parallel with an off-chip inductor. The antenna can be tuned to any of the 5 bands of sub-4 GHz cellular spectrum between 690 MHz and 3800 MHz with return loss exceeding 6 dB at the feed over more that 95% of the total frequency range. A systematic design and analysis of the penta-band IFA based on transmission line model is provided, tuning approach for carrier aggregation enablement over two bands at a time is discussed. A nonlinear performance of the designed antenna with RF capacitors fabricated in bulk-CMOS RF-switch technology is demonstrated.
CRIS-Team Scopus Importer:2021-10-08
Keywords: Antenna tuning; aperture tuning; C-tuner; carrier aggregation; cellular user equipment; harmonics; high-voltage RF switch; inverted-F antenna; mobile handset; RF switch; switchable capacitor; user terminal

People Counting Solution Using an FMCW Radar with Knowledge Distillation From Camera Data - Stephan, Michael; Hazra, Souvik; Santra, Avik; Weigel, Robert; Fischer, Georg (2021 IEEE SENSORS, 2021)
Radar systems enable remote sensing of multiple persons within their field of view. In this paper, we propose a novel architecture to perform people counting using a 60 GHz Frequency Modulated Continuous Wave radar trained on supervised radar data and knowledge distillation performed using synchronized camera data. In the evaluation phase, only the radar encoder with Range - Doppler Images (RDI) as input is used and tested on a dataset consisting of scenarios recorded in a different setup than the training recordings with up to 6 persons present. In this paper we focus on showing the benefit of using the cross-modal camera information compared to the same unimodal model. In spite of the low-cost radar sensor, the proposed architecture achieves an accuracy of 71% compared to 58% for the test data from a different sensor with a different orientation and aspect angle, and an accuracy of 89% compared to 74% for test data from the same radar sensor when training without knowledge distillation.<br
CRIS-Team WoS Importer:2022-02-25

Perceptual Audio Coding - von mp3 bis zum heutigen Tage - Brandenburg, Karlheinz; Herre, Jürgen; Grill, Bernhard (Festkolloquium anläßlich der Verleihung des Eduard-Rhein-Preises, 2015)
Eingeladene Vorträge auf Konferenzen etc.

Performance Analysis of a Cylindric Dielectric Lens Antenna for 77 GHz Automotive Radar - Wenig, Peter; Schneider, Martin; Weigel, Robert (International Radar Symposium, 2008)
elib2cris::1512001600,wenig2008a

Performance Analysis of an Ultra Wideband Transceiver for Real-Time Localization - Michler, Fabian; Deniz, Harun; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (2018 48th European Microwave Conference (EuMC), 2018)
In this paper, an ultra wideband localization system based on the DecaWave DW1000 chipset is investigated in detail regarding the achievable precision and accuracy in different measurement scenarios. System parameters, such as channel selection, bandwidth, preamble length and measurement method will be explained in detail and their influence on the localization performance is estimated. Statistically evaluated measurements in different environments with a prototype system consisting of a single anchor and a tag are then used to confirm the theory.<br

Performance Analysis of FMCW Synchronization Techniques for Indoor Radiolocation - Gierlich, Roland; Hüttner, Jörg; Dabek, Alexander; Huemer, Mario (Wireless Sensors & RF-Tcchnology (CT PS 7), 2007)
A high precision localization system (HPLS) operating in the 5.8 GHz ISM band is presented. The system principle is based on the sequential exchange of frequency modulated continuous wave (FMCW) signals between identical radar stations. The round-trip time-of-flight (RToF) localization method requires exact synchronization of all involved stations. Consequently, accurate compensation of clock frequency drift is indispensible. We analyze the impact of clock deviation on synchronization accuracy and present a precise compensation method. The synchronization technique has been tested on a prototype system. Measurements showed a 3D-position accuracy of 2.8 cm under laboratory conditions.
elib2cris::1512001600,gierlich2007

Performance Analysis of Time Difference of Arrival and Angle of Arrival Estimation Methods for GSM Mobile Phone Localization - Zimmermann, Lars; Götz, Alexander; Fischer, Georg; Weigel, Robert (Communication, Signal Processing & Information Technology, 2017)
The localization methods time difference of arrival (TDOA) and angle of arrival (AOA) are investigated in their capability of high-resolution detection of GSM signals. Because GSM is of narrowband nature, a bandwidth expansion technique that significantly increases the resolution of TDOA is introduced. The algorithms maximum likelihood estimator (for TDOA), root multiple signal classification and estimation of signal parameters via rotational invariance techniques (for AOA) are proposed as a reference for each method. Simulations conducted with noisy signals and multipath propagation demonstrate the potential of TDOA for GSM localization, especially for search and rescue applications. AOA on the other hand is very sensitive to multipath, and is therefore only recommended for open space scenario
Keywords: Time difference of arrival estimation; Direction of arrival estimation; GSM; Maximum likelihood estimation; Multiple signal classification; Estimation of signal parameters via rotational invariance techniques

Performance Improvement of UMTS Uplink Beamsteering with Limited Feedback at Higher Terminal Velocity by Designing Adapted Algorithms - Schröter, Simon; Brendel, Johannes; Weigel, Robert; Fischer, Georg (International Conference on Communications(ICC), 2014)

Performance of Coherent Time Delay Estimation Techniques for Frequency Hopping GSM Signals - Götz, Alexander; Rose, Richard; Zorn, Stefan; Fischer, Georg; Weigel, Robert (Topical Conference on Wireless Sensors and Sensor Networks (RWW / WiSNet), 2012)
In this paper, the performance of coherent time delay estimation techniques for frequency hopping GSM signals is investigated. It is demonstrated that the techniques enable the usage of a substantially higher bandwidth for time delay estimation and localization purposes compared to state-of-the-art techniques. Since resolution and noise performance directly depend on the applied bandwidth of the signals, major improvements can be realized. For E-GSM 900 systems, an overall bandwidth of up to 35 MHz may be used which enables time delay estimation and localization in the scale of a few meters. The coherent time delay estimation techniques are therefore ideally suited for search and rescue applications.
elib2cris::1512001600,goetz2012
Keywords: GSM; TDOA; Localization; Frequency Hopping

Performance Optimization of a Differential Method for Localization of Capsule Endoscopes - Zeising, Samuel; Ararat, Kivanc; Thalmayer, Angelika; Anzai, Daisuke; Fischer, Georg; Kirchner, Jens (7th International Electronic Conference on Sensors and Applications, 2020)

Permittivity Reduction and Surface Modification by Porosification of LTCC - Steinhäußer, Frank; Talai, Armin; Kölpin, Alexander; Weigel, Robert; Bittner, Achim; Schmid, Ulrich (Ceramics International, 2016)
The wet-chemical porosification of low temperature co-fired ceramics is investigated with respect to the resulting permittivity reduction and surface modification. Therefore, four commercially available tapes were treated and characterized by measuring the detuning of a resonator as well as by chromatic white light and scanning electron microscopy analyses. The results show a technically relevant permittivity reduction of about 15 to 18% measured at a frequency of 44 GHz. Thereby, the vertical distribution of the air, embedded by the porosification is of high influence. The achievable reduction in permittivity strongly counteracts the surface quality, which is necessary for applying high quality metallization lines.
elib2cris::1512001600,steinhaeusser2016a
Keywords: LTCC; porosification

Phased Array Antenna Model Applied to Acoustic Surface-to-Bulk Wave Conversion in Arbitrary Metalic Gratings on Piezoelectric Substrates - Weigel, Robert; Herzinger, Stefan; Müller, Günter (Proc. URSI International Symposium on Electromagnetic Theory, 1995)
elib2cris::1512001600,weigel1995

Phased Array Approach for Vehicle-to-Infrastructure Communication in Train Stations - Lichtblau, Johann; Michler, Fabian; Scheiner, Benedict; Lurz, Fabian; Gräbner, Martin; Hundhausen, Mira; Weigel, Robert; Kölpin, Alexander (2019 IEEE Radio and Wireless Symposium (RWS), 2019)

Phase-Locked Loop Based Frequency Synthesizer with Chirp Generation for FMCW Secondary Radar Systems - Ußmüller, Thomas; Weigel, Robert (IEEE International Conference on Wireless Information Technology and Systems, 2010)
elib2cris::1512001600,ussmueller2010

Phasenrauscharmer Frequenzssynthesizer mit sehr feiner Frequenzauflösung für GSM900/DCS1800 - Märzinger, Günther; Neurauter, Burkhard; Lüftner, Thomas; Weigel, Robert; Scholz, Markus; Mutlu, Varol; Fenk, Josef (Austrochip, 2000)
elib2cris::1512001600,maerzinger2000
Keywords: Synthesizer; GSM; Low phase noise

Phasenschieber für satellitenfunkempfänger-frontends / A phase shifter for satellite radio receiver frontends - Rascher, Jochen; Ußmüller, Thomas (GMM Fachbericht 70: ANALOG 2011, 2011)
In this publication the advantages of passive phase shifters are shown which can be used in integrated satellite radio receiver frontends at 2.3GHz center frequency. High large signal robustness, low temperature dependency, and low inser- tion loss <1dB per phase bit can be achieved. The 3 bit phase shifter design uses FET switches in resistive body floating technique for that.
elib2cris::1512001600,rascher2011

Physically inspired digital predistortion for doherty power ampliers and automatic in-situ identication - Donati, Giovanni; Musolff, Christian; Gottardo, Giuseppe; Popp, Daniel; Fischer, Georg (Fifth International Conference on Telecommunications and Remote Sensing, 2016)

Pilot Aided Timing synchronization for SC-FDE and OFDM: A Comparison - Reinhardt, Steffen; Weigel, Robert (IEEE International Symposium on Communications and Information Technology (ISCIT), 2004, 2004)
This paper deals with the pilot aided synchronization techniques for single carrier systems with frequency domain equalization (SC/FDE). This techniques are also useable for OFDM. Normally the following parameters have to be synchronized for a mobile communication system: carrier frequency and phase, clock frequency and phase and the position within a transmitted frame. In mobile communication systems, where multipath propagation occurs, a channel estimation and equalization is additionally necessary. In SC/FDE systems a very efficient, low complexity equalizer is implemented, that furthermore synchronizes the clock and carrier phase automatically. That is an important advantage of SC/FDE versus OFDM. The most critical point in burst communication systems is the frame detection and timing synchronization. This paper compares different techniques for timing synchronization and carrier frequency offset estimation.
elib2cris::1512001600,reinhardt2004
Keywords: OFDM modulation; channel estimation; equalisers; clocks; frequency-domain analysis; mobile radio; frame detection; clock phase

Planar Acoustooptic Interactions in Lithium Niobate - Weigel, Robert (Proc. International Conference on Nonlinear Optics, 1988)
null::1512001600,weigel1988b

Planar Coils for Detection of Magnetic Nanoparticles in a Testbed for Molecular Communication - Bartunik, Max; Faghih-Naini, Samira; Maiwald, Timo; Kirchner, Jens (Proceedings of the 9th ACM International Conference on Nanoscale Computing and Communication, NANOCOM 2022, 2022)
Testbeds enable experimental investigation of molecular communication concepts and transmission schemes. One approach to biocompatible molecular communication, implemented in a testbed, is the use of magnetic nanoparticles as information carriers. These nanoparticles can be detected based on their high susceptibility using an inductive sensor. So far, a wire-wound sensing coil, that requires manual manufacturing and is difficult to install for a real-life transmission channel, was used. Here, we propose the use of planar coils. To this end, a selection of commercially available coils are evaluated in comparison to a conventional wire-wound coil as reference. A planar coil is then successfully used to detect magnetic nanoparticles in the context of the molecular communication testbed. The contribution is concluded with an outlook on future improvements made possible through the application of planar sensing coils.
CRIS-Team Scopus Importer:2022-11-11
Keywords: Magnetic nanoparticles; Molecular communication; Testbed

Planar cross-polarized transition to a circular waveguide feed for a 61 GHz dielectric antenna - Stein, Wadim; Deckelmann, Maximilian; Oborovski, Andreas; Vossiek, Martin (9th German Microwave Conference, GeMiC 2015, 2015)
This paper presents a novel concept for a planar cross-polarized transition to a 61 GHz dielectric lens antenna. The transition to the circular waveguide antenna feed consists of a combination of a microstrip line and a slot line. Each of these planar waveguides excites the H11 mode in the circular waveguide with a 90± polarization angle to one another. The developed double layer transition topology was realized on a Rogers 5880 substrate employing the microstrip line on the top and the slot line on the bottom layer. The concept was implemented and tested on a circular waveguide-fed dielectric lens antenna for a 61 GHz radar system. Experimental results show a transition loss of around -2 dB for the microstrip and -3 dB for the slot line feed with excellent crosstalk suppression greater than 40 dB for the two polarization channels. The bandwidth of the built crosspolarized transition is greater than 10 GHz. The results prove that the novel transition concept is very well suited for compact, broadband and low cost polarimetric millimeter-wave radar systems.
Keywords: millimeter-waves; planar to waveguide transitions; polarization; slotlines

Planare akustooptische Lichtablenker in Lithiumniobat - Weigel, Robert (Proc. Kolloquium Integrierte Optik der Deutschen Forschungegemeinschaft, 1989)
–empty–::1512001600,weigel1989a

Planar phased array for the purpose of reception of vertical and horizontal polarized signals from different satellite systems when mounted perpendicularly - Fischer, Georg (COST-245 Workshop, 1995)

P-matrix model for third order electric and acoustic nonlinearities in TC-SAW devices - Chauhan, Vikrant; Mayer, Markus; Ruile, Werner; Wagner, Karl; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE International Ultrasonics Symposium, 2018)

PMSE-xG – 5G for Programme Making and Special Events - Bühlmeyer, Jonas; Hertlein, Markus; Fischer, Georg (2nd International Conference on Signals and Systems 2018 (ICSigSys 2018), 2018)
This paper provides a short overview over the prerequisites for the use of 5G for Programme Making and Special Event (PMSE). These will be shortly discussed in the context of the current development of 5G and the German research and development (R&D) project PSMExG. In the project PMSE-xG different use cases of PMSE were examined and demonstration models will be created. This paper focuses on the use of 5G for broadband, low latency and ultra-reliable video streaming in production scenarios like motion picture or television studios. For a first attempt 4G+ software defined radio (SDR) solutions are used to measure the critical parameters and to emphasize the important aspects. After the abstract some general information about the project will be given and the project is further introduced. Subsequently the project partners shall be introduced. Then the different use cases will be presented in short. Afterwards the high data rate streaming will be discussed in focus. Some measurements with two different Software Defined Radio (SDR) platforms are presented then. These results will be discussed before the result will be summariz
Keywords: PMSE-xG; PMSE; 5G; LTE; 4G; SDR; USRP; MIMO; Networking; Communications

PMSE-xG –Wireless Communication in Mobile Networks for Programme Making and Special Events - Hertlein, Markus; Bühlmeyer, Jonas; Elhaddad, Ahmed; Fischer, Georg (2nd International Conference on Signals and Systems 2018 (ICSigSys 2018), 2018)
This paper provides a short overview of the German research and development (R&D) project PMSE-xG, which aims to create the prerequisites for using the next mobile standard for broad-band low-latency ultra-reliable connections (5G) especially for Programme Making and Special Events (PMSE). The PMSE manufacturers have so far focused on highly specialized, link-based solutions. This strategy was undermined by the fact that more and more spectrum is assigned to mobile communication systems like Long Term Evolution (LTE). Therefore, both technologies are competing for the rare spectrum. Working with the current standard for wireless communication Long Term Evolution (LTE), the PMSE-xG project is a first feasibility study to integrate PMSE applications into a mobile communication standard and aims to integrate these different use cases of PMSE through future projects into 5G. Through the interaction and cooperation with different stakeholders from industry, research, standardization, regulation and users, PMSE-xG tries to achieve this. Furthermore, it will lay the foundations for other vertical industries in 5G and for further cooperation with them. Furthermore, the video demonstrator is introduced in this paper. Still some work has to be done but the goals of the project are reachabl
Keywords: PMSE; SDR; LTE; 5G; low-latency; broad-band; ultra-reliable wireless communication

Polarization Coupling Effects in a Dual-Polarized Aperture Antenna for Multiband Base Stations - Fischer, Georg; Wiesbeck, Werner; Waldschmidt, Christian; Pivit, Florian (IEEE Antennas and Propagation Society International Symposium, 2005)
The paper shows that the proposed antenna covers multiple mobile communication frequency bands, it shows the stable performance of the antenna within these frequency bands and states the capability of its polarization diversity feature.
elib2cris::1512001600,fischer2005

Polar Transmitter Linearization with Digital Predistortion - Weigel, Robert; Ceylan, Nazim; Müller, Jan-Erik (Proc. European Microwave Conference, 2004)
elib2cris::1512001600,weigel2004a

Polyharmonic Distortion Modeling of RF BAW Components - Tag, Andreas; Akstaller, Wolfgang; Musolff, Christian; Bader, Bernhard; Pitschi, Maximilian; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE International Microwave Symposium, 2015)
elib2cris::1512001600,tag2015a

Poröses LTCC als Substratmaterial für Höchstfrequenzradarsensoren - Bittner, Achim; Steinhäußer, Frank; Talai, Armin; Kölpin, Alexander; Weigel, Robert; Rittweg, Thomas; Schwanke, Dieter; Sandulache, Gabriela; Hansal, Wolfgang; Schmid, Ulrich (International Conference on Electromagnetics in Advanced Applications (ICEAA), 2015)
elib2cris::1512001600,bittner2015

Porösizierte Glaskeramik-Substrate für die Radarsensorik - Talai, Armin; Kölpin, Alexander; Bittner, Achim; Steinhäußer, Frank; Schmid, Ulrich; Kölpin, Alexander (Automobil-Sensorik 2, 2018)
Für Komfortfunktionen und aktive Sicherheitsfunktionen werden in modernen Fahrzeugen Radarsensoren im freigegebenen Frequenzband zwischen 77 GHz und 79 GHz benötigt. Um einen langzeitstabilen Betrieb bei gleichzeitig geringer Baugröße der Radarsensoren zu gewährleisten, müssen robuste Materialsysteme mit geeigneten dielektrischen Eigenschaften im Bereich der Aufbau- und Verbindungstechnik verwendet werden. Kommerzielle LTCC (engl.: low temperature cofired ceramics) Glaskeramiksubstrate ermöglichen einen dreidimensionalen Aufbau bei hervorragenden Hochfrequenzeigenschaften. Um die Antennencharakteristik zu optimieren, wird ein Porösizier-Verfahren vorgestellt, um eine lokal reduzierte Permittivität zu erreichen. Dabei wird nasschemisch das Glaskeramikmaterial porösiziert, um oberflächennah eine Schicht mit reduzierter dielektrischer Konstante zu erzielen. Diese wird durch den Vergleich von Hochfrequenzmessungen mit numerischen Simulationsergebnissen bestimmt.<br
Keywords: Radar; Automotive; LTCC

Portable and Scalable High Voltage Circuits for Automotive Applications in BiCMOS Processes - Easwaran, Sri Navaneeth; Camdzic, Samir; Weigel, Robert (Proceedings of the Custom Integrated Circuits Conference, 2019)
CRIS-Team Scopus Importer:2019-08-20

Positioning with a Software Receiver under weak tracking conditions with software simulated - Kaniuth, Roland; Eissfeller, Bernd; Lemke, Norbert; Heinrichs, Günther; Winkel, Jón; Ehm, Henning; Weigel, Robert; Schmid, Andreas; Neubauer, André; Nagel, Peter (Institute of Nagigation Conference, 2005)
An important step into the market for Galileo is the intime availability of large-scale integrated combined Galileo/GPS receiver chipsets for consumer applications. This is the main idea behind the HIGAPS project – the development of the concept for an integrated combined Galileo/GPS receiver that is specially tailored for location based services and consumer market applications - preferably for pedestrian and vehicular users. The HIGAPS project is a national project, commonly funded by the Bavarian Ministry of Economic Affairs, Infrastructure, Transport, and Technology and the German Aerospace Center DLR. The consortium consists of Ifen GmbH, Infineon Technologies AG, the Fraunhofer Institute of Integrated Circuits in Erlangen, the Institute of Geodesy and Navigation of the University FAF Munich and the Chair of Electronics of the University Erlangen- Nuremberg. The first part of the paper focuses on the main concept and the initial architecture of the future integrated combined Galileo/GPS receiver for location based services and consumer applications. Particularly the integration into a mobile phone platform introduces challenges e.g. due to cost constraints and power consumption. The actual status of the project will be presented. This includes an analysis of the reception and boundary conditions that lead to the development of the presented receiver architecture. The development platforms are presented and an outlook on the future work in this project is given. In the second part of the paper a static and kinematic experiment are shown to demonstrate the performance of the proposed snap-shot approach for the HIGAPS receiver.
elib2cris::1512001600,kaniuth2005b
Keywords: Galileo; receiver

Positions- und Geschwindigkeitsmessung mit Mikrowellen am Beispiel Kfz-Radar - Kissinger, Dietmar; Weigel, Robert (Workshop Mikrowellenmesstechnik, 2008)
elib2cris::1512001600,kissinger2008

Post-Processing and Evaluation for a Radar Based True-Speed-Over-Ground Estimation System - Reißland, Torsten; Michler, Fabian; Scheiner, Benedict; Kölpin, Alexander; Weigel, Robert (IEEE Microwave and Wireless Components Letters, 2021)
This work presents a cross-correlation based true-speed-over-ground estimation approach based on experiences from an earlier system. The radar system parameters as well as the antenna configuration were adapted to fit the requirements of the presented application. Also, challenges regarding the previously limited velocity range are addressed and an appropriate solution is proposed. The entire system was thoroughly tested in a train scenario over a wide range of velocities. Very promising measurement results are presented and compared to related approaches.
Keywords: Estimation; Receiving antennas; Antenna measurements; Velocity measurement; Wireless communication; Radar; Radar tracking; fmcw; cross-correlation; velocity; train

Power Control of a Switching Amplifier for GSM Handsets - Koller, Rainer; Stelzer, Andreas; Freudenthaler, Klaus; Abt, Karl-Heinz; Maurer, Linus; Weigel, Robert (Asia-Pacific Microwave Conference (APMC), 2002)
Maximizing the effciency of GSM handset power amplifers (PA) for a signifcant increase of talktime is the main aim in new design approaches. One of them is the utilization of switching amplifers, since they offer extremely high effciency and their disadvantages are not applicable to constantenvelope modulation schemes like GMSK used in the GSM system. Among them, the Class-E amplifer concept is best suited, because it allows about 80% effciency, while maintaining an excellent output spectrum and reasonable gain. Since the power transistor operates as a switch, the input signal envelope is not reproduced accordingly at the output. In this paper, three ways of output power control are presented and compared: Variable supply voltage by utilizing a DC/DC converter, a serial transistor and PA mixed mode operation by reducing the gate voltage swing.
elib2cris::1512001600,koller2002

Praktikumsversuch CW/FMCW-Radar auf Basis von myRIO - Gardill, Markus; Linz, Sarah; Fischer, Georg; Weigel, Robert (Virtuelle Instrumente in der Praxis 2015, 2015)
Im Rahmen der Akademischen Bildungsinitiative zur Elektromobilität Bayern – Sachsen, gefördert durch die Initiative Schaufenster Elektromobilität der Bundesregierung, ist an der FAU Erlangen-Nürnberg ein neuer Praktikumsversuch zum Thema drahtlose Automobilelektronik entstanden. Im Rahmen dieses Praktikumsversuchs entwicklen und evaluieren die Studierenden ein CW/FMCW Radarsystem bei 24GHz. Das Radarsystem besteht dabei lediglich aus zwei Hardwarekomponenten: einem industriellen low-cost Radar Frontend sowie der National Instruments myRIO Plattform, es sind keine weiteren Hardwarekomponen-ten notwendig. In diesem Beitrag wird gezeigt, wie die myRIO Plattform in diesem Praktikumsversuch eingesetzt wird und wie mit myRIO somit kostengünstig ein technisch anspruchsvoller Versuch im Bereich der Mikrowellentechnik realisiert wird.
elib2cris::1512001600,gardill2015

Präsenzdetektion von Personen in Innenräumen mittels CO2-Gassensorik - Zimmermann, Lars (RADCOM, 2013)
elib2cris::1512001600,zimmermann2013a

Precise and Fast Frequency Determination of Resonant SAW Sensors by a Low-Cost Six-Port Interferometer - Lurz, Fabian; Lindner, Stefan; Mann, Sebastian; Linz, Sarah; Weigel, Robert; Kölpin, Alexander (IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2016)
Surface acoustic wave (SAW) resonators are used for a broad range of wireless sensing applications, some of them having high demands on the resolution as well as the measurement update rate. This paper presents a new interrogation method for precise and fast frequency determination of passive SAW resonators based on instantaneous frequency measurement (IFM) by a low-cost Six-Port interferometer. By using a delay line the frequency measurement is reduced to a phase measurement that can be instantaneously evaluated by the Six-Port structure. No complex signal processing is necessary providing high update rates and low hardware costs. A demonstrator in the 2.4 GHz frequency band shows the feasibility and the precision of the concept with measurement times of only a few microseconds.
elib2cris::1512001600,lurz2016a

Predicting Request Success with Objective Features in German Multimodal Speech Assistants - Weber, Mareike; Halimeh, Mhd Modar; Kellermann, Walter; Popp, Birgit (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2022)
We investigate whether objective features, like occurrence of an error and number of turns, can automatically predict success in interactions with multimodal speech assistants. We used interactions from the SmartKom corpus, a data set on multimodal interactions with virtual assistants in German. In a first step, we segmented the interactions into requests and labeled them as successful or unsuccessful. Afterwards, we defined task success as the average of request success rate. Next, we investigated whether subjective features such as emotions expressed by users show a relation to task success. We find no significant correlation. Finally, we exploited objective features, e.g., number of turns to predict request success. We find that objective features suffice to reach F1 scores over 0.9 (prediction of successful requests) and F0 scores above 0.83 (prediction of unsuccessful requests). Finally, we discuss implications of our findings for automatic evaluation of pragmatic aspects of user experience.
CRIS-Team Scopus Importer:2022-06-10
Keywords: German; Logistic regression; Multimodal; Random forest; Request success; Speech assistant; Task success

Prediction of Time Variant Spatial Channel Impulse Responses for Wireless Ad-hoc Networks - Wahl, René; Wölfle, Gerd; Weigel, Robert (16th IST Mobile and Wireless Communications Summit, 2007)
With the growing demand for wireless communication systems, wireless concepts for the data exchange in time variant ad-hoc networks become more and more interesting. In order to describe and thus assess the mobile radio channels in such networks, simulations are required. The main aspect is the time-variance of the channel impulse response and the modeling of large scenarios. This paper discusses the demands for a model to describe the radio channel in time variant environments and presents an appropriate ray tracing approach. A new concept is introduced to substitute complex polygonal objects by several radar cross sections. The performance of the Ray Tracing algorithm is demonstrated by a comparison from predictions to measured channel characteristics.
elib2cris::1512001600,wahl2007a
Keywords: ad hoc networks; ray tracing; transient response; wireless channels; appropriate ray tracing approach; mobile radio channel; time variant spatial channel impulse response; wireless ad-hoc network; wireless communication system; Ad hoc networks; Airports; Land mobile radio; Mobile communication; Optical propagation; Optical transmitters; Radar cross section; Ray tracing; Vehicle dynamics; Wireless communication; Ad-hoc Networks; Car-to-Car Communication; Cars; Radar Cross Section; Ray Optical; Ray Tracing; Time Variant; Vehicles

Proceedings of the FH Science Day - Gierlich, Roland; Hüttner, Jörg; Mosshammer, Ralf; Huemer, Mario (FH Science Day: Proceedings (Berichte Aus Der Medizinischen Informatik Und Bioinformatik), 2007)
elib2cris::1512001600,gierlich2007a

Processor Error Detection Capabilities of Random Programs - Kohl, Johannes; Bauer, Wolfgang; Bäsig, Jürgen; Rübesam, Stefan; Fey, Dietmar (Tagungsband TuZ 2017, 2017)
UnivIS-Import:2017-12-18:Pub.2017.tech.IMMD.IMMD3.proces

Program FFlexCom - High frequency flexible bendable electronics for wireless communication systems - Meister, Tilo; Ellinger, Frank; Bartha, Johann W.; Berroth, Manfred; Burghartz, Joachim; Claus, Martin; Frey, Lothar; Gagliardi, Alessio; Grundmann, Marius; Hesselbarth, Jan; Klauk, Hagen; Leo, Karl; et al. (2017 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS), 2017)
Keywords: flexible electronics; radiocommunication; DFG Priority Program FFlexCom; flexible bendable electronics; wireless communication systems; Integrated circuit modeling; Metals; Microwave antennas; Substrates; Thin film transistors; Wireless communication

Programmable Systems for Intelligence in Automobiles (PRYSTINE): Final results after Year 3 - Druml, Norbert; Ryabokon, Anna; Schorn, Rupert; Koszescha, Jochen; Ozols, Kaspars; Levinskis, Aleksandrs; Novickis, Rihards; Nigussie, Ethiopia; Isoaho, Jouni; Solmaz, Selim; Stettinger, Georg; Diaz, Sergio; et al. (2021 24TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN (DSD 2021), 2021)
Created from Fastlane, WoS look-up

Programmable Systems for Intelligence in Automobiles (PRYSTINE): Technical Progress after Year 2 - Druml, Norbert; Debaillie, Bjom; Anghel, Andrei; Ristea, Nicolae-Catalin; Fuchs, Jonas; Dubey, Anand; Reißland, Torsten; Hartstem, Maike; Rack, Viktor; Ryabokon, Anna; Ozols, Kaspars; Novickis, Rihards; et al. (2020 23rd Euromicro Conference on Digital System Design (DSD), 2020)
Autonomous driving has the potential to disruptively change the automotive industry as we know it today. For this, fail-operational behavior is essential in the sense, plan, and act stages of the automation chain in order to handle safety-critical situations by its own, which currently is not reached with state-of-the-art approaches.The European ECSEL research project PRYSTINE realizes Fail-operational Urban Surround perceptION (FUSION) based on robust Radar and LiDAR sensor fusion and control functions in order to enable safe automated driving in urban and rural environments. This paper showcases some of the key results (e.g., novel Radar sensors, innovative embedded control and E/E architectures, pioneering sensor fusion approaches, AI controlled vehicle demonstrators) achieved until year 2.<br
Keywords: Digital systems; FUSION; fail-operational; perception

Progress of Six-Port technology for industrial radar applications - Vinci, Gabor; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2016)
Six-Port receivers are well-known in the microwave test and measurement community since decades. The basic network topology has been implemented for simple reflectometer applications as well as complex network analysis. In the last decade however, a new application area for this receiver technology has been explored: Radar. Year after year new applications have been covered by radar systems taking benefit of the complex additive mixing technique of Six-Port receivers. Especially, innovative radar measurement solutions for industrial applications have been addressed by developing new hardware based on this receiver topology. In this paper, an overview of Six-Port technology will be given focusing on industrial applications that benefit from this receiver technique, the advantages as well as the drawbacks of this technology.
elib2cris::1512001600,vinci2016
Keywords: Six-Port; Radar

Promise of a Better Position - Vinci, Gabor; Lindner, Stefan; Barbon, Francesco; Weigel, Robert; Kölpin, Alexander (IEEE Microwave Magazine, 2012)
Industrial automation today is an essential technology underlying our modern society. Advanced positioning and sensor feedback tasks in automation processes often require distance displacement detection, e.g., to measure and track the movement of robots. Furthermore, the detection of mechanical stress in complex industrial machinery through an accurate vibration analysis is often a task of major interest. Therefore, high-resolution distance measurements with short- and long-range positioning are important for a large number of sensing applications and can also be used as a precondition for vibrometer applications. Several automation technologies rely on high precision positioning sensors to track linear as well as rotational movements of various machiner
elib2cris::1512001600,vinci2012g
Keywords: Automation; Displacement measurement; Feedback; Industrial plants; Machinery; Position measurement; Robot sensing systems; Sensors; Tracking; Six-Port

Proposed Mobile Controlled Handoff (MCHO) in 3GPP Long Term Evolution (LTE) system - Chauhan, Vikrant; Gupta, Juhi; Singla, Chhavi (Springer's 5th International Conference on Contemporary Computing, 2012)
elib2cris::1512001600,chauhan2012

Protocol Design for Ultra-Low Power Wake-Up Systems for Tracking Bats in the Wild - Dressler, Falko; Blössl, Bastian; Hierold, Martin; Hsieh, Chia-Yu; Nowak, Thorsten; Weigel, Robert; Kölpin, Alexander (EEE International Conference on Communications (ICC 2015), 2015)

Protocol Stack Optimization With Cellular IoT Applications - Irnstorfer, Florian; Elhaddad, Ahmed; Dümler, Burkhard; Fischer, Georg (embedded world Conference 2022, 2022)

Prototyping Memristors in Digital Systems with an FPGA-Based Testing Environment - Wust, Daniel; Biglari, Mehrdad; Knödtel, Johannes; Reichenbach, Marc; Söll, Christopher; Fey, Dietmar (Power and Timing Modeling, Optimization and Simulation (PATMOS), 2017 27th International Symposium on, 2017)
Toward integrating memristors in CMOS-based designs flexible prototyping environments are necessary. However, research in digital memristive systems so far lacks an adequate testing platform for real world devices. To achieve better handson experience, we developed a flexible FPGA-based solution which allows to link memristors with arbitrary compute units such as MIPS, ARM processor cores or own custom designs. The testing environment is comprised of two main components: a dedicated hardware interface circuit for steering discrete memristor devices and a memory controller as IP core establishing the communication with the hardware interface utilizing an easy-to-use AXI interface. Furthermore, in order to integrate the prototyping platform in processing systems a C API is supplied. This testing environment lays the foundation for integrating memristors in future hybrid CMOS-based SoCs. The platform is put into practice for evaluating a ternary processor on physical hardware using memristors as multi-level storage cells.
Keywords: memristor test platform; memristive computing; FPGA; off-the-shelf devices

Proximity sensors on common noctule bats reveal evidence that mothers guide juveniles to roosts but not food - Ripperger, Simon; Günther, Linus; Wieser, Hanna; Duda, Niklas; Hierold, Martin; Cassens, Björn; Kapitza, Rüdiger; Kölpin, Alexander; Mayer, Frieder (Biology Letters, 2019)

Prüfmaschine schärft multiphysikalisches Modell - Ehlenz, Tobias; Fischer, Georg; Wittmann, Armin (Draht, 2018)

Pulsation and Interference in Narrowband Systems - Buzid, Tufik; Huemer, Mario; Weigel, Robert; Jondral, Friedrich (Globecom 2006, 2006)
elib2cris::1512001600,buzid2006

Pulse-Based Ultra-Wideband Ground Penetrating Radar for Anti-Personnel Landmine Detection - Oßberger, Gerald; Buchegger, Thomas; Schimbäck, Erwin; Stelzer, Andreas; Weigel, Robert (Proceedings of the European Microwave Association, 2006)
elib2cris::1512001600,ossberger2006a

Pulsed Frequency Modulation Techniques for High-Precision Ultra Wideband Ranging and Positioning - Waldmann, Benjamin; Gulden, Peter; Vossiek, Martin; Weigel, Robert (IEEE International Conference on Ultra-Wideband, ICUWB 2008, 2008)
In this paper a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. The system combines the advantages of FMCW radar systems and the advantages of the use of a wide bandwidth. With this concept, a high accuracy in dense multipath indoor environments can be achieved, ideally suited for ID, 2D, and 3D localization. A prototype was fabricated which operates around the center frequency of 7.5 GHz utilizing a bandwidth of 1 GHz. With the setup presented in this paper the distance between two wireless units can be measured achieving a low standard deviation.
UnivIS-Import:2015-04-16:Pub.2008.tech.IE.LEH.pulsed

Pulse noise in thin film disk recording systems - Obernosterer, Frank; Oehme, Friedrich (Journal of Magnetism and Magnetic Materials, 1996)
The effect of media noise on pulse amplitude and pulse shape variation has been investigated at a thin film disk drive. In a new approach total amplitude noise is divided into a reproducible (deterministic) part and a random part. At higher pulse interference position jitter is identified as source of additional random amplitude noise. From pulse shape analysis it is concluded that flying height and transition length are the reasons for the observed amplitude variations.
UnivIS-Import:2015-03-05:Pub.1996.tech.IE.LETE.pulsen

Pulse Plated Silver Metallization on Porosified Low Temperature Co-fired Ceramics for High Frequency Applications - Steinhäußer, Frank; Talai, Armin; Sandulache, Gabriela; Weigel, Robert; Kölpin, Alexander; Hansal, Wolfgang; Bittner, Achim; Schmid, Ulrich (Microelectronics Reliability, 2016)
Advanced high frequency systems such as needed in modern radar applications, require high conductive metallizations as well as substrates with areas of variable permittivity. This paper presents the combination of the selective porosification technology of low temperature co-fired ceramics and electro pulse plated silver microstrip lines. By means of selective plating methods, line widths of 20 μm can be manufactured featuring low resistivity values down to 2.33 μΩ·cm, without detectable pore penetration. The substrate permittivity is measured facilitating a combined method of ring resonator detuning and 3D field simulations resulting in a reduction of 6.5% with a shift from approx. 7.52 to 7.03 at 66 GHz due to the porosification. As often outlined in literature the major challenge in using silver as a conductor lies in its high tendency of agglomeration and microstructural transformation especially in oxygen containing atmosphere even at low temperatures. Therefore, the effect of different temperature loads up to 500°C on the dc film resistivity are measured using the VAN DER PAUW technique and compared to scanning electron microscope analyses.
elib2cris::1512001600,steinhaeusser2016
Keywords: LTCC; porosification

Pulse Wave Velocity Detection Using a 24 GHz Six-Port Based Doppler Radar - Michler, Fabian; Shi, Kilin; Schellenberger, Sven; Scheiner, Benedict; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (IEEE Radio and Wireless Symposium (RWS), 2019)

QoS based Deep Reinforcement Learning for V2X Resource Allocation - Bhadauria, Shubhangi; Shabbir, Zohaib; Roth-Mandutz, Elke; Fischer, Georg (2020 IEEE International Black Sea Conference on Communications and Networking, BlackSeaCom 2020, 2020)
The 3rd generation partnership project (3GPP) standard has introduced vehicle to everything (V2X) communi-cation in Long Term Evolution (LTE) to pave the way for future intelligent transport solutions. V2X communication envisions to support a diverse range of use cases for e.g. cooperative collision avoidance, infotainment with stringent quality of service (QoS) requirements. The QoS requirements range from ultra-reliable low latency to high data rates depending on the supported application. This paper presents a QoS aware decentralized resource allocation for V2X communication based on a deep reinforcement learning (DRL) framework. The proposed scheme incorporates the independent QoS parameter, i.e. priority associated to each V2X message, that reflects the latency required in both user equipment (UE) and the base station. The goal of the approach is to maximize the throughput of all vehicle to infrastructure (V2I) links while meeting the latency constraints of vehicle to vehicle (V2V) links associated to the respective priority. A performance evaluation of the algorithm is conducted based on system level simulations for both urban and highway scenarios. The results show that incorporating the QoS parameter (i.e. priority) pertaining to the type of service supported is crucial in order to meet the latency requirements of the mission critical V2X applications.
CRIS-Team Scopus Importer:2020-12-04
Keywords: DRL; QoS; resource allocation; V2X communication

QoS Based Multi-Agent vs. Single-Agent Deep Reinforcement Learning for V2X Resource Allocation - Bhadauria, Shubhangi; Ravichandran, Lavanya; Roth-Mandutz, Elke; Fischer, Georg (2021 IEEE Symposium On Future Telecommunication Technologies (SOFTT) - Artificial Intelligence, 2021)
Autonomous driving requires Vehicle-to- Everything (V2X) communication as standardized in the 3rd generation partnership project (3GPP). Diverse use cases and service types are foreseen to be supported, including safety-critical use cases, e.g., lane merging and cooperative collision avoidance. Each service type's quality of service (QoS) requirements vary enormously regarding latency, reliability, data rates, and positioning accuracy. In this paper, we analyze and evaluate the performance of a QoS-aware decentralized resource allocation scheme using first, a single-agent reinforcement learning (SARL) and second, a multi-agent reinforcement learning (MARL) approach. In addition, the impact of multiple vehicular user equipments (V-UEs) supporting one and multiple services are considered. The QoS parameter considered here is the latency and the relative distance between the communicating V-UEs, which is mapped on the Priority to reflect the required packet delay budget (PDB). The goal is to maximize the throughput of all V2N links while meeting the V2V link's latency constraint of the supported service. The results based on a system-level simulation for an urban scenario show that MARL improves the throughput for V-UEs set up for single and multiple services compared to SARL. However, for latency SARL indicates advantages at least when multiple services per V-UE apply.<br
Keywords: V2X; QoS; Deep Reinforcement Learning; SARL; MARL

Quad-Band Inverted-F Antenna System Tuned by Hybrid C-Tuner - Özdamar, Oguzhan; Solomko, Valentyn; Weigel, Robert; Hagelauer, Amelie (2021 IEEE ASIA-PACIFIC MICROWAVE CONFERENCE (APMC), 2021)
CRIS-Team WoS Importer:2022-05-20

Quality of service aspects of a 5.8 GHz radiolocation system - Mosshammer, Ralf; Huemer, Mario; Weigel, Robert (IEEE Radio and Wireless Symposium (RWS), 2009)
elib2cris::1512001600,mosshammer2009

Quality Testing for AR and VR in MPEG-I Immersive Audio - Sporer, Thomas; Jelfs, Sam; Herre, Jürgen (Proceedings of DAGA 2023, 2023)
Vorträge und Veröffentlichungen auf Konferenzen_Virtual and Augmented Reality
Keywords: Augmented Reality; Virtual Reality

Quantenphysikalische Bauelemente - Weigel, Robert; Russer, Peter (Springer-Verlag, 1992)
elib2cris::1512001600,weigel1992a

Quartz pressure sensor based on SAW reflective delay line - Scherr, Holger; Scholl, Gerd; Seifert, Franz; Weigel, Robert (IEEE International Ultrasonics Symposium (IUS), 1996)
elib2cris::1512001600,scherr1996

Quasi-Differential Operation of Capacitive Tuners for Aperture Tuning Applications - Solomko, Valentyn; Özdamar, Oguzhan; Thomas, Anthony; Weigel, Robert; Hagelauer, Amelie Marietta (2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems, COMCAS 2019, 2019)
A method of operating a switch-based series capacitive tuner in quasi-differential mode is proposed. The method suggests to split the applied RF voltage between the terminals of the tuner such that the terminals see the out-of-phase voltage waveforms with reduced amplitudes. The proposed approach allows minimizing power losses in the parasitic shunt resistive elements of the capacitive tuner. The same approach may be applied to antenna tuning switches as well.The method is evaluated on a capacitive tuner integrated circuit fabricated in bulk-CMOS RF-switch technology. The network based on the prototype operating in quasi-differential mode demonstrated a potential to reduce power losses by up to 15% when operating at high-ohmic aperture tuning plane.
CRIS-Team Scopus Importer:2020-02-21
Keywords: antenna tuning; aperture tuning; c-tuner; high-voltage RF switch; IFA

Quasi-Static Magnetic Localization of Capsule Endoscopes with an Active Integrated Coil - Zeising, Samuel; Seidl, Rebecca; Thalmayer, Angelika; Fischer, Georg; Kirchner, Jens (2021 IEEE Sensor Application Symposium, 2021)

Quaternary-Vector-List for totally computational treating of switching algebraic tasks - Can, Yavuz (ICAT 2017, 2017)
In this paper an advanced form of vector-list called quaternary-vector-list QVL is introduced. QVL is the computational representation of Boolean function or switching function respectively and enables the total computational treatment of switching algebraic tasks. It has advantages in terms of memory usage, simplicity, clarity and also in computation time. Furthermore, important operations as complement, intersection and union are demonstrated for the advanced QVL-arithmetic. By the use of QVL the computational utilization of the extended Basis function forms of switching function will be granted. By QVL the already available ternary-vector-list TVL is supplemented and substitute
Keywords: Quaternary-Vector-List; Switching Function; Normal Form; Algorithms; Combinational Circuit; Operation Rule

Quick Macroscopic Diffusion-Based Molecular Communication with Wavelike Propagation by Use of a Suspension of Relay Cells - Kirchner, Jens (IEEE Communications Letters, 2023)
In order to enable molecular communication on macroscopic distances without a moving medium, the model of diffusion-based information transmission with a large number of relays suspended in the medium, hence at random positions, is proposed. With an increasing number of relays, the stochastic variations approach zero and the system exhibits a quasi-deterministic behavior. Furthermore, the transmission time becomes inversely proportional to the number of relays and the impulse response independent of the channel length. Thus, the model describes a wave-like propagation, which is fundamentally different from the established flow- and diffusion-based approaches in molecular communication.<br
Keywords: Molecular communication; diffusion; relays; propagation; multi-hop network; transmission time; impulse response

Radar-Based Efficient Gait Classification using Gaussian Prototypical Networks - Niazi, Usman; Hazra, Souvik; Santra, Avik; Weigel, Robert (2021 IEEE RADAR CONFERENCE (RADARCONF21): RADAR ON THE MOVE, 2021)
CRIS-Team WoS Importer:2021-09-10

Radar-Based Gesture Recognition Using a Variational Autoencoder With Deep Statistical Metric Learning - Stadelmayer, Thomas; Santra, Avik; Weigel, Robert; Lurz, Fabian (IEEE Transactions on Microwave Theory and Techniques, 2022)
Radar-based gesture recognition systems are a promising concept for new human-machine interfaces. However, the systems are sensitive to user-dependent gesture patterns, sensor noise characteristics, background environments, and unknown gestures or background motions. To overcome such challenges, we propose a variational autoencoder architecture-based deep metric learning, which is optimized using a novel loss function combining a statistical distance triplet loss and the center loss. By learning the statistical distance between distributions, the proposed solution, compared with triplet loss, is able to better learn the nonlinear characteristics in the data, is less sensitivity to training strategy, and is capable of creating close knit embedding clusters. Moreover, it is experimentally demonstrated that the proposed gesture recognition system using radar spectrograms has improved classification accuracy and random gesture rejection accuracy compared with the state-of-the-art deep metric learning approaches. Furthermore, we proof the real-world capability of the system by implementing a real-time demonstrator, which allows playing "Tetris" with hand gestures.
CRIS-Team WoS Importer:2022-09-23

Radar-Based Heart Sound Detection - Will, Christoph; Shi, Kilin; Schellenberger, Sven; Steigleder, Tobias; Michler, Fabian; Fuchs, Jonas; Weigel, Robert; Ostgathe, Christoph; Kölpin, Alexander (Scientific Reports, 2018)
This paper introduces heart sound detection by radar systems, which enables touch-free and continuous monitoring of heart sounds. The proposed measurement principle entails two enhancements in modern vital sign monitoring. First, common touch-based auscultation with a phonocardiograph can be simplified by using biomedical radar systems. Second, detecting heart sounds offers a further feasibility in radar-based heartbeat monitoring. To analyse the performance of the proposed measurement principle, 9930 seconds of eleven persons-under-tests' vital signs were acquired and stored in a database using multiple, synchronised sensors: a continuous wave radar system, a phonocardiograph (PCG), an electrocardiograph (ECG), and a temperature-based respiration sensor. A hidden semi-Markov model is utilised to detect the heart sounds in the phonocardiograph and radar data and additionally, an advanced template matching (ATM) algorithm is used for state-of-the-art radar-based heartbeat detection. The feasibility of the proposed measurement principle is shown by a morphology analysis between the data acquired by radar and PCG for the dominant heart sounds S1 and S2: The correlation is 82.97 ± 11.15% for 5274 used occurrences of S1 and 80.72 ± 12.16% for 5277 used occurrences of S2. The performance of the proposed detection method is evaluated by comparing the F-scores for radar and PCG-based heart sound detection with ECG as reference: Achieving an F1 value of 92.22 ± 2.07%, the radar system approximates the score of 94.15 ± 1.61% for the PCG. The accuracy regarding the detection timing of heartbeat occurrences is analysed by means of the root-mean-square error: In comparison to the ATM algorithm (144.9 ms) and the PCG-based variant (59.4 ms), the proposed method has the lowest error value (44.2 ms). Based on these results, utilising the detected heart sounds considerably improves radar-based heartbeat monitoring, while the achieved performance is also competitive to phonocardiography.

Radar-based monitoring of glass fiber reinforced composites during fatigue testing - Moll, Jochen; Maetz, Thomas; Maelzer, Moritz; Krozer, Viktor; Mischke, Kevin; Krause, Stefan; Bagemiel, Oliver; Nuber, Andreas; Kremling, Stefan; Kurin, Thomas; Lurz, Fabian; Weigel, Robert; et al. (Structural Control & Health Monitoring, 2021)
This work aims at radar sensors in the frequency band from 57 to 64 GHz that can be embedded in wind turbine blades during manufacturing, enabling non-destructive quality inspection directly after production and structural health monitoring (SHM) during the complete service life of the blade. In this paper, we show the fundamental damage detection capability of this sensor technology during fatigue testing of typical rotor blade materials. Therefore, a frequency modulated continuous wave (FMCW) radar sensor is used for damage diagnostics, and the results are validated by simultaneous camera recordings. Here, we focus on the failure modes delamination, fiber waviness (ondulation), and inter-fiber failure. For each failure mode, three samples have been designed and experimentally investigated during fatigue testing. A damage index has been proposed based on residual, that is, differential, signals exploiting measurements from pristine structural conditions. This study shows that the proposed innovative radar approach is able to detect continuous structural degradation for all failure modes by means of gradual signal changes.
CRIS-Team Scopus Importer:2021-07-02
Keywords: damage detection; fatigue testing; glass fiber reinforced materials; radar-based structural health monitoring; wind turbine blades

Radar-Based Vital Sign Monitoring - Michler, Fabian; Weigel, Robert; Kölpin, Alexander (International Microwave Symposium (IMS), 2019)
The continuous measurement of human vital parameters is an important diagnostic tool in human medicine. Conventional measurement devices, such as the electrocardiograph (ECG) or the photoplethysmograph (PPG), require a direct contact to the patients, limiting their independence and mobility. These drawbacks can be overcome by using high-precision radar systems for a contactless monitoring of the patients. In this talk, the physiological parameters of interest, respiration and heartbeat and related diagnostic parameters, such as heartsounds and pulse wave propagation will be introduced. In the next step, their impact on the movement of the body surface will be derived. A suitable concept for a highly precise radar system combined with state-of-the-art algorithms will be presented, which is able to measure the required relative displacements of the patient’s skin. As proof of concept, the measurement results of a medical proband study will be shown and discussed in detail. This also includes a possible medical evaluation of the sensed parameters and an outlook on potential areas of application for the proposed systems.<br

Radarbasiertes Structural Health Monitoring der Rotorblätter von Windkaftanlagen - Will, Christoph; Sporer, Michael; Sebald, Nina; Weigel, Robert; Kölpin, Alexander; Fuchs, Jonas (Kleinheubacher Tagung, 2017)

Radarbasierte und vernetzte Umfeldsensorik zur autonomen Steuerung von Industrierobotern - Wibbing, Sascha; Mann, Sebastian; Lurz, Fabian; Frank, Martin; Weigel, Robert; Kölpin, Alexander (VDE Kongress 2016: Internet der Dinge, 2016)
Im Zuge der so genannten vierten industriellen Revolution, kurz Industrie 4.0 genannten Initiative der Bundesregierung ist ein Hauptmerkmal die dynamische Anpassung von bislang unflexiblen Produktionseinrichtungen auf sich wechselnde Anforderungen und Umgebungsfaktoren. Besonders in Bezug auf autonom agierende Systeme wie beispielsweise Industrieroboter werden zur Realisierung solcher Anforderungen vor allem leistungsfähige Sensoren und Steuerungen benötigt. In diesem Artikel wird ein vernetztes Sensorsystem bestehend aus mehreren RADAR-Sensoren beschrieben, welche durch mehrdimensionale Sensordatenfusion ein 3D-Bild der Umgebung erstellen. Zur Vernetzung werden dabei vor allem bestehende und etablierte Netzwerktechniken zur Datenübertragung verwendet. Die Systemarchitektur und die Komponenten eines einzelnen Sensorknotens sowie der zentralen Steuereinheit werden im Detail erörtert. Im Anschluss daran werden verschiedene Messungen hinsichtlich Performanz und Auflösung präsentiert und erläutert.
elib2cris::1512001600,wibbing2016b

Radar Image Reconstruction from Raw ADC Data using Parametric Variational Autoencoder with Domain Adaptation - Stephan, Michael; Stadelmayer, Thomas; Santra, Avik; Fischer, Georg; Weigel, Robert; Lurz, Fabian (25th International Conference on Pattern Recognition, 2021)

Radarsystemtechnik und Radarsignalverarbeitung für Automobilanwendungen - Yang, Bin; Schoor, Michael; Weigel, Robert; Wenig, Peter; Schoeberl, T.; Hilsebecher, J.; Binzer, Thomas; Brüggemann, Oliver (VDE-Kongress 2006 - Innovations for Europe - Fachtagungsberichte der ITG/BMBF - GMM - ETG - GMA - DGBMT, 2006)
Dieser Artikel gibt eine kurze Beschreibung der Radarsystemtechnik und Radarsignalverarbeitung fuer Automobilanwendungen im Rahmen des BMBF-Projekts KRAFAS. Das Ziel des Projekts ist die Untersuchung kostenguenstiger Realisierungskonzepte für zukuenftige 77 GHz-Weitbereich-Radarsensoren mit einer verbesserten Umfeldsensierung. Neben Systemueberlegungen werden in diesem Artikel besondere Aspekte im HF-Frontend und in Basisband-Signalverarbeitung diskutiert
elib2cris::1512001600,yang2006

Radio Frequency Integrated Circuits for Cellular Communication Terminals: Current Developments and Future Trends - Weigel, Robert; Hagelauer, Richard (Informationstagung Mikroelektronik 2003, 2003)
This paper will report on the RF-related system and radio frequency integrated circuit (RFIC) issues of mobile radio terminals in general. In particular, we consider RFICs for third-generation wideband code division multiple access (3G W-CDMA) systems like UMTS, and we present the worldwide first single-chip, intermediate frequency (IF) transceiver for W-CDMA applications.
elib2cris::1512001600,weigel2003a

Radio Frequency Integrated Circuit System Design for UMTS Terminal Receivers - Weigel, Robert; Springer, Andreas; Maurer, Linus (International Series of Numerical Mathematics, 2003)
elib2cris::1512001600,weigel2003

Radio Hardware In-the-Loop Emulation for Testing Vehicular Communication Systems - Franchi, Norman; Fischer, Georg; Weigel, Robert (5th IEEE International Symposium on Wireless Vehicular Communications - VTC Spring 2013, 2013)
In this work, a novel test concept Radio Hardware In-the-Loop (RadioHIL) for next generation automotive electronic control units (ECUs) with wireless interfaces is proposed. The resulting test environment is well suited for ECUs networking with wireless sensors, actuators, mobile terminals or even with other vehicles and infrastructure elements. The presented RadioHIL approach is based on Software Defined Radio (SDR) architecture. The first step for executing the RadioHIL concept is the implementation of a multi-standard waveform design for automotive relevant purposes. Therefore the model-based implementations of two compliant IEEE 802.11b and 802.11p SDR transmitters are outlined, which are of interest for vehicular wireless communication. The emulation concept is demonstrated on the Universal Software Radio Peripheral (USRP) SDR platform.
elib2cris::1512001600,franchi2013b
Keywords: Software Defined Radio; Vehicular Wireless Communication; Wireless Automotive Sensor Networks; Hardware In-the-Loop; IEEE 802.11p; IEEE 802.11b; USRP; RadioHIL

Range-Doppler-Analyse von FMCW-Sekundärradar-basierten Lokalisierungssystemen - Kaiser, Markus (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

Rauscharme SAW-Oszillatoren im GHz-Bereich - Weigel, Robert; Russer, Peter (Proc. Kleinheubacher Tagung, 1992)
elib2cris::1512001600,weigel1992

Reader Architectures for Wireless Surface Acoustic Wave Sensors - Lurz, Fabian; Ostertag, Thomas; Scheiner, Benedict; Weigel, Robert; Kölpin, Alexander (Sensors, 2018)

Reader Concept for Wireless Resonant Surface Acoustic Wave Instrumentation based on Instantaneous Frequency Measurement - Lurz, Fabian; Halder, Ernst; Dingler, Peter; Sept-Enzel, Gerold; Scheiner, Benedict; Weigel, Robert; Kölpin, Alexander (SAW Sensor & Actuator Symposium, 2018)

Read Range and Power Efficiency of the UHF RFID Systems - Iliev, Stoyan; Luy, Johann-Friedrich; Weigel, Robert (German Microwave Conference, 2009)
This paper presents a new analytical model for analysis and determination of the read range and the power efficiency of the UHF RFID systems, that takes into account the effects of the nonlinear transponder front end.
elib2cris::1512001600,iliev2009
Keywords: UHF RFID systems; nonlinear transponder front end; radiofrequency identification; read range

Realization of the Scanning Subsystem - Brendel, Johannes; Rieß, Steffen (Öffentlicher Workshop des C-PMSE Projekts, 2012)
elib2cris::1512001600,brendel2012c

Real-Time GSM Broadcast Receiver on a Cortex-M4 Microcontroller - Erhardt, Stefan; Pflaum, Felix; Weigel, Robert; Kölpin, Alexander (Radio & Wireless Week, 2018)
Recent microcontrollers provide enough computing power to perform signal processing while still being energy efficient and enable more flexibility than FPGAs. A fully functional GSM broadcast receiver was implemented on a Cortex-M4 microcontroller that is able to decode broadcast control channel (BCCH) messages. With several algorithmic optimizations it is able to operate in real-time in combination with a Sub-GHz transceiver as RF front-end. The timing was proven by measurements with an logic analyzer.

Receiver structures for MIMO-SC/FDE Systems - Reinhardt, Steffen; Buzid, Tufik; Huemer, Mario (IEEE 63rd Vehicular Technology Conference, 2006. VTC 2006-Spring, 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 the conventional MMSE-equalizer equation is not suited in conjunction with optimal matched filtering and we derive a novel MMSE structure
elib2cris::1512001600,reinhardt2006a
Keywords: equalisers; filtering theory; least mean squares methods; matched filters; multiplexing; radio receivers; signal processing

Receiving GSM Broadcast Channels with an Ultra-Low Power Sub-GHz Transceiver - Erhardt, Stefan; Weigel, Robert; Kölpin, Alexander (European Microwave Conference, 2017)
Mobile phone front-end and baseband modules are hard to obtain on the market for end customers. Thus, software defined radios are widely used in research and development, enabling many opportunities for digital signal processing. In this publication a novel option to receive GSM signals is suggested by using an ultra-low power Sub-GHz transceiver in a legacy mode. The device outputs raw demodulated bits while the signal processing is realized in software. The functionality is proven and quantified by measurements.

Receiving Mode CST MWS – Matlab Co-Simulations for Time and Frequency Domain UWB Small Antenna Array Characterization - Gardill, Markus; Fischer, Georg; Weigel, Robert; Kölpin, Alexander (CST European User Group Meeting 2013, 2013)
Using current simulation technology the simulation setup for a small antenna array (no Unit-Cell approach) generally is as follows: the complete antenna array structure is modeled in CST MWS and a port is assigned to each antenna element. The simulation can then be performed by either exciting a single element only while all others are terminated with their port reference impedance, which would e.g. yield the active element pattern, the embedded element impedance, and the TX mode element coupling S-Parameters. Alternatively the simulation can be performed using a simultaneous excitation of all ports, with a predefined phase and amplitude distribution. This yields the pattern of the complete array for the defined excitations as well as the scan impedance for every element. However, both approaches lead to a description of the antenna array in transmit mode only, but it is a well-known fact that the TX mode characteristics differ from the RX mode characteristics significantly. In our contribution we propose a Matlab – CST Co simulation framework for simulating antenna arrays in receive mode. Therefore, we developed a Matlab function which excites the complete structure using plane waves impinging on the array from various directions of interest, records the output signals of all ports as well as the Plane wave signal (using ResultReaderDLL) and finally postprocesses the outputs to get state-of-the-art frequency and time-domain characteristics for UWB antennas and antenna arrays. In the presentation we give an introduction to the problem of UWB receiving antenna array characterization, we introduce the state-of-the-art frequency and time-domain figures of merit for UWB antennas and antenna arrays, we introduce our simulation framework, and we discuss simulation results. The simulation framework Matlab code will be available to interested users for fre
elib2cris::1512001600,gardill2013d

Receiving Mode Simulations for Ultra-Wideband Characterization of Small Antenna Arrays and a Novel Look on Mutual Coupling - Gardill, Markus; Fischer, Georg; Weigel, Robert; Kölpin, Alexander (Applied Computational Electromagnetics Society Conference, 2013)
Using conventional commercially available computational electromagnetics (CEM) simulation packages the simulation setup for a small antenna array generally is as follows: the complete antenna array structure is modeled in the simulation tool and the simulation is sequentially performed by exciting each single antenna element while all others are terminated with their port reference impedance. This yields a complete characterization of the array in transmit (TX) mode. However, it is a well-known fact that the TX mode characteristics differ from the receive (RX) mode characteristics significantly and the results obtained from a TX mode simulation do not necessarily capture the RX case. In this contribution we first propose an extended model for characterizing RX mode ultra-wideband (UWB) antenna-arrays, with a novel look on the RX mode coupling phenomena. Based on the theory, we propose our computational framework for accurate simulations of small receiving UWB antenna arrays. We further present simulation results for some exemplary UWB antenna arrays and discuss our novel viewpoint on RX mode array coupling.
elib2cris::1512001600,gardill2013b

Recent Trends in Wafer-Level Package Technology - Schmidbauer, Philipp; Wojnowski, Maciej; Pressel, Klaus; Weigel, Robert; Hagelauer, Amelie Marietta (International Wireless Symposium, 2020)

Rechnergestuezter Entwurf von gekoppelten Oberflaechenwellenresonatorfilern - Christ, Andreas; Ruile, Werner; Russer, Peter; Scholl, Gerd; Weigel, Robert (Proc. Kleinheubacher Tagung, 1990)
93781a41-0f22-4bbe-83c8-b30fb0ad65d3::1512001600,christ1990

Rechnergestuezter Entwurf von GUDT-Filtern fuer Funkkommunikationsanwendungen - Weigel, Robert; Russer, Peter; Bauregger, Josef; Anemogiannis, Kimon (Proc. MIOP'93, 1993)
elib2cris::1512001600,weigel1993h

Reconfigurable and efficient GaN based power amplifiers for frequency agile RF Systems in mobile communication basestations - Fischer, Georg (IWPC workshop on reconfigurable radios for versatile basestations, 2006)
elib2cris::1512001600,fischer2006j

Reconfigurable FMCW-based high-precision real-time positioning system. - Ußmüller, Thomas; Mosshammer, Ralf; Weigel, Robert; Carls, Jörg; Eickhoff, Ralf; Ellinger, Frank; Hüttner, Jörg; Gierlich, Roland; Ziroff, Andreas; Huemer, Mario; Wehrli, Silvan; Jäckel, Heinz; et al. (Radio and Wireless Symposium, 2009)
elib2cris::1512001600,ussmueller2009

Reconfigurable Inverted-F Antenna for MIMO Cellular User Equipment - Özdamar, Oguzhan; Weigel, Robert; Wang, Kun; Solomko, Valentyn; Hagelauer, Amelie (2021 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, APWC 2021, 2021)
MIMO (multiple input multiple output) systems are utilized more and more in modern handheld cellular devices. Because of the limited space, the mutual coupling effect between the antennas increases significantly. In order to reduce the coupling between antennas various decoupling and matching networks are implemented. In this work, a concept for reconfigurable inverted-F antenna for MIMO RF frontends in cellular user terminals is proposed. The main component of the system is the RF switch-based IC (integrated circuit), which was manufactured in Infineon 130 nm RF switch technology. The chip reconfigures the physical length of the inverted-F antenna (IFA), making the antenna longer for low-band operation and splitting the antenna in two IFAs for middle/high band MIMO operation. The proposed concept implements MIMO approach with 19 dB isolation between the antennas at 1.8 GHz while sustaining good efficiency at 900 MHz.
CRIS-Team Scopus Importer:2021-10-15
Keywords: antenna tuning; aperture tuning; C-Tuner; decoupling; IFA; matching; MIMO; PIFA; RF capacitor; RF high-voltage switch

Reconfigurable RF and Baseband Architectures for Mobile Transceivers - Maurer, Linus; Weigel, Robert (Wireless World Research Forum, 2001)
With the rapid advancement of wireless personal communication services, a new challenge to this industry is the integration of multiple systems and applications on a single device. Although a fourthgeneration wireless communication standard will address the goal of a global standardization once again, it is more realistic to anticipate a core standard plus several extensions, which might cover the integration of already deployed systems like GSM, the IMT-2000 standards, Hyper LAN, Blue Tooth, WLAN and the like. These systems differ in many respects. To begin with, they normally have incompatible air interface access techniques (TDD, CDMA, FDMA, TDD/CDMA, TDD/FDMA, OFDM), use different frequency bands and channel bandwidths, vary in their baseband receiver implementations (e.g. RAKE receiver for CDMA technology) and coding schemes. A transceiver, which can be totally redefined in software, is commonly known as software defined radio (SDR) [1]. However, an SDR approach which is based only on software reconfiguration seems too extreme to the author taking into consideration the estimated power consumption, which is still an essential problem in mobile transceiver design, of such an SDR based transceiver. Instead, we propose an approach which is based on reconfigurable hardware in the RF and in the baseband section combined with the exploitation of already possible readjustments of the transceiver software part. This approach is known as “flexible radio architecture” (FAR).
elib2cris::1512001600,maurer2001b

Reconfigurable Systems for Mobile Local Communication and Positioning - Ußmüller, Thomas; Mosshammer, Ralf; Weigel, Robert; Eickhoff, Ralf; Ellinger, Frank; Ziroff, Andreas (IEEE MTT-S International Microwave Symposium, 2008)
elib2cris::1512001600,ussmueller2008b

Reconstruction of 3D-Movement of ICD Leads from Clinical-Routine X-Ray Movies - Kirchner, Jens; Fischer, Georg; Arnold, Martin (2017 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT), 2017)
A technique is proposed to reconstruct the threedimensional movement of leads of implantable cardioverter defibrillators from X-ray movies obtained as part of clinical routine during implantation. The technique is applied to data from 16 patients. 12 of them provide results with a sufficient accuracy of less than 2.5 mm in terms of half of the minimum distance of the projection lines and when compared to the length of the shock coil as reference. From the reconstructed 3D data, the movement along and perpendicular to the lead axes as well as tilt are obtained. Such data will prove useful in research on material fatigue and cardiac sensors integrated into the lead
Keywords: cardiology; defibrillators; diagnostic radiography; image reconstruction; medical image processing; prosthetics; reconstructed 3D data; lead axes; implantable cardioverter defibrillators; three-dimensional movement; clinical-routine X-ray movies; ICD leads; 3D-movement; shock coil; projection lines; minimum distance; motion pictures; electric shock lead; heart; X-ray imaging; image reconstruction; signal processing; ICD; lead; cardiac movement; X-ray movie; 3D reconstruction; implantation

Reduced Size and Tunable Microwave Circuits Using BST Thin-Film Varactors - Lourandakis, Errikos; Schmidt, Matthias; Leidl, Anton; Seitz, Stefan; Weigel, Robert (German Microwave Conference, 2008)
elib2cris::1512001600,lourandakis2008

Reduced Size Frequency Agile Microwave Circuits Using Ferroelectric Thin-Film Varactors - Lourandakis, Errikos; Schmidt, Matthias; Seitz, Stefan; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2008)
A new concept for tunable and reduced size microwave circuits is presented based on barium-strontium-titanate (BST) varactors. The proposed design methodology relies on substitution of quarter-wavelength transmission line segments with their equivalent low-pass structures. The ferroelectric BST-varactors are used as tuning elements and allow for a frequency agile behavior and size reduction of the circuit. Candidates for this methodology are quarter-wavelength based circuits such as Wilkinson power dividers and branch-line couplers. Prototype boards for both topologies were implemented and characterized through scattering parameter measurements. For the implemented Wilkinson divider a tuning range from 1.7 to 2.1 GHz is achieved. The insertion loss in both output paths varies from 0.6 to 1.2 dB while maintaining a worst case amplitude- and phase difference of 0.5 dB and 9deg, respectively, for all operating cases. The isolation between the two output ports exceeded 25 dB over the whole tuning range. The implemented branch-line coupler exhibits a tuning range from 1.8 to 2.3 GHz with a maximum insertion loss of 2.7 dB while maintaining worst case amplitude- and phase difference of 0.4 dB and 90deg plusmn 5deg, respectively. Port matching and isolation levels of more than 15 dB are exhibited at all bias conditions.
elib2cris::1512001600,lourandakis2008d

Reduced Steering Performance in Magnetic Drug Targeting Induced by Shielding Arising from Accumulation of Particles - Thalmayer, Angelika; Zeising, Samuel; Fischer, Georg (Current Directions in Biomedical Engineering, 2022)

Reducing Dispersion in Molecular Communication by Placing Decelerators in the Propagation Channel - Thalmayer, Angelika; Ladebeck, Alisa; Zeising, Samuel; Fischer, Georg (7th Workshop on Molecular Communications, 2023)

Reducing Dispersion in Molecular Communications by Placing Decelerators in the Propagation Channel - Thalmayer, Angelika; Ladebeck, Alisa; Zeising, Samuel; Fischer, Georg (IEEE Transactions on Molecular, Biological and Multi-Scale Communications, 2023)

Reducing RF front-end requirements for CDMA receiver - Chabrak, Karim; Hueber, Gernot; Maurer, Linus; Weigel, Robert (IEEE Radio and Wireless Symposium 2006, RWS 2006, 2006)
This paper gives an introduction to receiver requirements for CDMA systems like IS-95 and cdma2000 1xRTT. From the specification in term of frame error ratio, the requirements on Eb/N0 are first derived. This papers explains how in the RAKE receiver the noise from the RF part and the orthogonal channels can effect the signal to noise ratio after despreading and demodulation and proposes how to reduce this effect which relaxes the requirements on phase noise and linearity in the receiver Front-end.
elib2cris::1512001600,chabrak2006

Reduction in human interaction with magnetic resonant coupling wpt systems with grounded loop - Duan, Xianyi; Lan, Junqing; Diao, Yinliang; Gomez-Tames, Jose; Hirayama, Hiroshi; Hotta, Masashi; Fischer, Georg; Hirata, Akimasa (Energies, 2021)
Wireless power transfer (WPT) systems have attracted considerable attention in relation to providing a reliable and convenient power supply. Among the challenges in this area are maintaining the performance of the WPT system with the presence of a human body and minimizing the induced physical quantities in the human body. This study proposes a magnetic resonant coupling WPT (MRC-WPT) system that utilizes a resonator with a grounded loop to mitigate its interaction with a human body and achieve a high-efficiency power transfer at a short range. Our proposed system is based on a grounded loop to reduce the leakage of the electric field, resulting in less interaction with the human body. As a result, a transmission efficiency higher than 70% is achieved at a transmission distance of approximately 25 cm. Under the maximum-efficiency conditions of the WPT system, the use of a resonator with a grounded loop reduces the induced electric field, the peak spatial-average specific absorption rate (psSAR), and the whole-body averaged SAR by 43.6%, 69.7%, and 65.6%, respectively. The maximum permissible input power values for the proposed WPT systems are 40 and 33.5 kW, as prescribed in the International Commission of Non-Ionizing Radiation Protection (ICNIRP) guidelines to comply with the limits for local and whole-body average SAR.
CRIS-Team Scopus Importer:2021-11-19
Keywords: Computational dosimetry; Grounded loop; Human safety; Specific absorption rate (SAR); Spiral coil; Wireless power transfer

Reduction of PLL Loop Gain Variations by Digital Calibration - Münker, Christian; Weigel, Robert (ITG/GMM Workshop - Testmethoden und Zuverlaessigkeit, 2006)
elib2cris::1512001600,muenker2006a

Redundant and Non-Redundant Parts of a Switching Function by Bi-Decomposition. - Can, Yavuz (30th International Workshop on Post-Binary ULSI Systems (ULSIWS2021), 2021)

Reference Generation for A/D Converters - Ohnhäuser, Frank; Huemer, Mario (International Symposium on Signals, Systems and Electronics, 2007)
An analog-to-digital converter (ADC) compares the input voltage Vin with a reference voltage REF to convert it into a digital word. The reference source must be able to drive the ADCs reference input; it needs to provide low noise, should be adjustable, stable over temperature and supply voltage and should not require external components. A novel scheme was developed and implemented in a 12bit 2MSPS SAR converter.
elib2cris::1512001600,ohnhaeuser2007

Reflection, Refraction, and Self-Jamming - Schnabel, Raik; Mittelstraß, Delf; Binzer, Thomas; Waldschmidt, Christian; Weigel, Robert (IEEE Microwave Magazine, 2012)
elib2cris::1512001600,schnabel2012

Reflector-based Broadband Antennas offering low profile - Malhotra, Sambhav; Irnstorfer, Florian; Fischer, Georg (Swedish Microwave Days 2023, 2023)
Broadband antennas offering low profile are becoming increasingly important as they provide devices with improved support for multiple frequency bands. A broadband antenna has a large bandwidth (one octave or higher), making them ideal for various technologies such as cellular, Wi-Fi, Bluetooth and navigation. Broadband antennas also reduce the number of antennas required in a single housing, ,by replacing multiple narrowband antennas with a single broadband antenna. Our work focuses on a subset of FR-1 frequency range [1] which goes from 600 MHz to 5 GHz, which covers cellular bands as well as Wi-Fi, Bluetooth and GPS.<br
Keywords: Broadband Antennas; spiral antenna; self complementary antennas; low profile

Regenerative Sampling Self-Mixing Receiver: A Novel Concept for Low Complexity Phase Demodulation - Carlowitz, Christian; Eßwein, Alexander; Weigel, Robert; Vossiek, Martin (IEEE International Microwave Symposium 2013, 2013)
In this paper, a novel low complexity receiver concept for high-order differential phase demodulation is introduced for the first time. With a first hardware demonstrator, a high data rate of 300 Mbit/s is achieved without requiring a synthesizer for downconversion. A phase sensitive regenerative sampling approach is employed that integrates both low noise amplifier and automatic gain control using a free running switched injection-locked oscillator with no need for stabilization by a phase locked loop. Differential phase detection is achieved by quadrature self-mixing the regenerated signal with one path delayed by the symbol period. This approach is particularly attractive in combination with the switched injection-locked oscillator due to its constant high output power that allows for matching the mixer's best operating point. The proposed concept is demonstrated at 5.5 GHz with 8th order differential phase shift keying and a symbol rate of 100 MBaud/s. A short range data rate of 300 Mbit/s is achieved at a bit error rate below 1e-3. © 2013 IEEE.
UnivIS-Import:2015-04-16:Pub.2013.tech.IE.LEH.regene
Keywords: Injection-locked oscillators; Receiver architectures; Signal sampling; Wideband communication

Region based Single-Stage Interference Mitigation and Target Detection - Dubey, Anand; Fuchs, Jonas; Madhavan, Venkat; Lübke, Maximilian; Weigel, Robert; Lurz, Fabian (IEEE Radar Conference, 2020)
The inherent smaller radar cross sections of vulnerable road users resulting in smaller signal-to-noise-ratios make an accurate detection of them somewhat challenging. Mutual radar interference in typical automotive scenarios further imposes the difficulty of a target detection by additionally raising the noise floor. The traditional signal processing pipeline consists of multiple but separate stages for interference detection, mitigation and target detection. In this paper, a convolutional neural network based autoencoder architecture is used to perform a combined single-stage target detection while generalizing over different interference noise. The proposed approach achieves significant improvement over state-of-the-art methods while preserving the instance of each target and is able to identify them uniquely in case of a partial occlusion or overlapping of multiple target
Keywords: automotive radar; convolutional autoencoder; interference mitigation; VRU detection

Reifendruck- und Reifentemperaturkontrollsystem basierend auf OFW-Transpondertechnik - Schimetta, Gernot; Weigel, Robert (ITG-Tagung Sensoren und Mess-Systeme, 2002)
elib2cris::1512001600,schimetta2002

Reifenzustandsüberwachung - OFW-Funksensorik für den Intelligenten Reifen - Schimetta, Gernot; Dollinger, Franz; Scholl, Gerd; Weigel, Robert (Elektrotechnik und Informationstechnik, 2001)
With the realization of a “smart tire”, capable of continuously transmitting information about its actual state, increased safety for passengers is achieved. The presented tire pressure and temperature measuring system is based on the application of surface acoustic wave (SAW) sensors. Since SAW sensors are powered by the energy of the RF field no battery is required inside the tire. The prototype of a tire pressure and temperature sensor featuring a typical pressure accuracy of ± 15 kPa and a heat stability up to 130° C is presented.
elib2cris::1512001600,schimetta2001
Keywords: Oberflächenwellenfilter; OFW-Messwertwandler; reflektive Verzögerungsleitung; Drucksensor; Reifendruck

Rekonfigurierbarer fraktionaler Frequenzsynthesegenerator zur hochpräzisen Positionsbestimmung mit FMCW-Sekundärradarsystemen - Ußmüller, Thomas (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2011)
elib2cris::1512001600,ussmueller2011

Reliabe Data Link for Power Transfer Control in an Inductive Charging System for Electric Vehicles - Sanftl, Benedikt; Joffe, Christopher; Trautmann, Martin; Weigel, Robert; Kölpin, Alexander (IEEE MTT-S International Conference on Microwaves for Intelligent Mobility, 2016)
This paper presents a novel data link for electric vehicles charged through inductive power transfer (IPT) systems. The data link uses the magnetically coupled coils as transmission medium. The data link is intended to transfer the instantaneous current and voltage values in the power receiving circuitry on the EV platform. One key goal is to enable robust and reliable communication for closed-loop operation of the IPT system. By careful system design the data link can be used in the noisy environment of the power transfer. For the communication architecture a fully digital approach is considered. The digital signal processing is done in an industrial controller thus, the data link can be implemented into existing systems with minimum changes. For proof of concept the communication system is connected to a 3 kW IPT system and evaluated. These key performance values for simultaneous power transfer and communication will be presented. The data link stands out with its high signal to noise ratio and error vector magnitude, consequently high reliability can be guaranteed.
elib2cris::1512001600,sanftl2016

Reliability-Based Improvement Strategies for LDPC Decoders - Lunglmayr, Michael (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2010)

Reliability of Edge Position Modulation for Wireless Infrared Communications - Lüftner, Thomas; Huemer, Mario; Hagelauer, Richard; Weigel, Robert; Hausner, Josef (World Multi-conference on Systemics, Cybernetics and Informatics (WMSCI), 2005)
elib2cris::1512001600,lueftner2005

Reliable and high-speed implant ultra-wideband communications with transmit–receive diversity - Anzai, Daisuke; Balasingham, Ilangko; Fischer, Georg; Wang, Jainqing (EAI/Springer Innovations in Communication and Computing, 2020)
CRIS-Team Scopus Importer:2020-12-04

Reliable and High-Speed Implant Ultra Wideband Communications with Transmit-Receive Diversity - Anzai, Daisuke; Balasingham, Ilangko; Fischer, Georg; Wang, Jianqing (EAI/Springer Innovations in Communication and Computing(15427), 2018)
Keywords: BAN; BAC

Reliable and High-Speed Implant Ultra-Wideband Communications with Transmit-Receive Diversity - Anzai, Daisuke; Balasingham, Ilangko; Fischer, Georg; Wang, Jianqing (13th EAI International Conference on Body Area Networks, 2020)
Keywords: BAC; Body Area Communication; Implant Communication; UWB; Loop Antenna

Remote Powered Medical Implants - Ußmüller, Thomas; Brenk, Daniel; Eßel, Jochen; Heidrich, Jürgen; Fischer, Georg; Weigel, Robert (MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO), 2013)
elib2cris::1512001600,ussmueller2013b

Remote powered medical implants for Telemonitoring (Invited Paper) - Walk, Jasmin; Kolpak, Jasmin; Söll, Christopher; Weigel, Robert; Fischer, Georg; Ußmüller, Thomas (Proceedings of the IEEE, 2014)
Chronicle diseases like diabetes mellitus often need a permanent monitoring of vital signs. Especially the use of telemedicine might increase the quality of life for concerned patients. New systems are required which permanently detect and provide health status information. But, these systems must not control patient’s life and shall work autonomous. For this purpose, intelligent medical implants are well qualiﬁed. The present work describes a system for wireless power supply and communication with medical implant applications. Monitoring vital signs might lead to a big amount of data. Therefore, high data rates are necessary provided by high operating frequencies. High frequencies in turn lead to high attenuation losses because of the frequency dependent relative permittivity ε_r of the human body. Hence, high frequencies are not suitable for energy transfer through the human body. The presented concept is based on two different frequencies for power supply and data transmission. An independent devel- opment of both blocks is possible. The power supply operates on 13.56 MHz using inductive coupling. Thereby, the human body doesn’t affect the energy transfer. In contrast, the data transmission is operated by a frequency of the Medical Implant Communication Service band. The elaborated system consists of an power supply unit, a data transmission unit and a control unit. The implementation of the power supply and data transmission as well as associated theoretical basics are presented. Performed measurements demonstrate that the realized system is qualiﬁed for the use on human beings.
elib2cris::1512001600,walk2014
Keywords: biological tissues; biomedical communication; biomedical power supplies; energy storage; frequency domain analysis; implantable biomedical devices; permittivity

Remote Powering Systems for Implantable Sensor Platforms - Walk, Jasmin; Ußmüller, Thomas; Weigel, Robert; Fischer, Georg (Radar, Communication & Measurement, RADCOM, 2011)
elib2cris::1512001600,walk2011a

Remote Powering Systems of Medical Implants for Maintenance Free Healthcare Applications - Walk, Jasmin; Ußmüller, Thomas; Weigel, Robert; Fischer, Georg (European Microwave Conference (EuMC), 2011)
For favorable health care sensor devices especially long term monitoring sensors have to be completely imperceptible and maintenance free. A solution on these requirements is an implantable sensor system. The permittivity of body tissue and the desired distance to a remote station confronts the technology with several challenges. To avoid compromises and to be able to optimize both, communication and remote energy supply, we defined a novel concept and split frequency ranges. With the provided system energy can be rectified at 13.56 MHz from a remote station. Its powering level is 10mW. To store the energy a buffering concept is calculated based on a capacitor of about 4μF. To harvest energy for 0.2 s is enough to supply low power sensor devices and a MICS-Band transmitter for communication at 402 MHz-405 MHz. The active time of the implanted transmitter is in the range of 5ms with a transmission power of approximately 25μW.
elib2cris::1512001600,walk2011c

RESOLUTION An Integrated Communications and Local Positioning Solution - Mosshammer, Ralf; Ußmüller, Thomas; Weigel, Robert (RadioTecC - Radio Techniques and Technologies for Commercial Communication and Sensing Applications, 2007)
elib2cris::1512001600,mosshammer2007a

RESOLUTION: Reconfigurable Systems for Mobile Local Communication and Positioning - Tragas, Philippos; Kalis, Antonis; Papadias, Constantinos; Ellinger, Frank; Eickhoff, Ralf; Ußmüller, Thomas; Mosshammer, Ralf; Huemer, Mario; Dabek, Alexander; Doumenis, Dimosthenes; Kounoudes, Anastassios (Mobile and Wireless Communications Summit, 2007)
RESOLUTION aims at developing a wireless three-dimensional (3-D) local positioning system with measurement accuracy in the centimetre regime and real-time ability. A novel frequency modulated continuous wave (FMCW) radar principle with pulsed active reflector is employed. This High-Precision-Localisation-System (HPLS) will be implemented together with common WLAN systems that are used for data communication purposes. Due to its high data rate capabilities and large potential bandwidth, the 802.11a/n standard allocated bandwidth around 5.5 GHz is applied. Special emphasis is given to the system's reconfigurability by efficiently using inherent synergies between the WLAN system and the HPLS approach. To allow multifunctional tasks, highly integrated system on chip (SoC) frontends will be designed on advanced CMOS or BiCMOS technology. Smart power and adaptive performance control will be applied to minimise the power consumption according to application needs. In order to enhance performance and coverage range, the transceiver features adaptive antenna combining (AAC) in the radio frequency (RF) receiver. AAC significantly decreases the power consumption, size and costs, since the number of multiple components is reduced to a minimum. Because of the high 3-D resolution and real-time ability, which can be achieved in indoor environments with strong multipath effects and fading, novel local positioning applications, e.g. for smart factories, robotics, interactive guiding, object tracking and augmented reality are presumably leading to a large economic potential.
elib2cris::1512001600,tragas2007a
Keywords: Adaptive Antenna Combining; High-Precision Localisation-System; voltage controlled oscillator

RESOLUTION: Reconfigurable Systems for Mobile Local Communication and Positioning - Tragas, Philippos; Kalis, Antonis; Papadias, Constantinos; Ellinger, Frank; Ußmüller, Thomas; Mosshammer, Ralf; Huemer, Mario; Dabek, Alexander; Doumenis, Dimosthenes; Kounoudes, Anastassios (16th IST Mobile and Wireless Communications Summit, 2007)
RESOLUTION aims at developing a wireless three-dimensional (3-D) local positioning system with measurement accuracy in the centimetre regime and real-time ability. A novel frequency modulated continuous wave (FMCW) radar principle with pulsed active reflector is employed. This High-Precision-Localisation-System (HPLS) will be implemented together with common WLAN systems that are used for data communication purposes. Due to its high data rate capabilities and large potential bandwidth, the 802.11a/n standard allocated bandwidth around 5.5 GHz is applied. Special emphasis is given to the system's reconfigurability by efficiently using inherent synergies between the WLAN system and the HPLS approach. To allow multifunctional tasks, highly integrated system on chip (SoC) frontends will be designed on advanced CMOS or BiCMOS technology. Smart power and adaptive performance control will be applied to minimise the power consumption according to application needs. In order to enhance performance and coverage range, the transceiver features adaptive antenna combining (AAC) in the radio frequency (RF) receiver. AAC significantly decreases the power consumption, size and costs, since the number of multiple components is reduced to a minimum. Because of the high 3-D resolution and real-time ability, which can be achieved in indoor environments with strong multipath effects and fading, novel local positioning applications, e.g. for smart factories, robotics, interactive guiding, object tracking and augmented reality are presumably leading to a large economic potential.
elib2cris::1512001600,tragas2007

Resource Efficient Gesture Sensing Based on FMCW Radar using Spiking Neural Networks - Arsalan, Muhammad; Chmurski, Mateusz; Santra, Avik; El-Masry, Moamen; Weigel, Robert; Issakov, Vadim (IEEE MTT-S International Microwave Symposium Digest, 2021)
Gesture recognition is a natural and intuitive human computer-interface compared to traditional interfaces such as mouse and keyboards. Radar forms a promising modality for portable gesture recognition systems, where minute finger motions can be easily sensed and processed to extract meaningful information presenting the user's intention. Compared to several conventional deep learning approaches that have been proposed in the literature, in this paper we present a novel spiking neural network (SNNs) for gesture recognition using a 60-GHz frequency modulated continuous wave radar (FMCW) chipset. SNNs are more hardware friendly and energy-efficient than their deep learning counterparts making them attractive for portable devices. We have demonstrated in measurement the application of SNN for the processing of radar data.
CRIS-Team Scopus Importer:2021-11-19
Keywords: Gesture Recognition; Spiking Neural Network

Respiration Extraction from Radar Heart Sound Measurements - Schellenberger, Sven; Shi, Kilin; Michler, Fabian; Lurz, Fabian; Weigel, Robert; Kölpin, Alexander (International Engineering in Medicine and Biology Conference, 2019)
Radar-based respiration measurement is susceptible to upper body movement in addition to the respiratory motion of the chest. This parasitic movement can only be canceled using a dual radar system from the front and back. However, the larger hardware effort could be avoided if a physiological parameter is measured that is influenced by respiration only but not by the movement. This could then be used to indirectly derive breathing. In this paper a method is presented, how the respiration can be deduced despite of upper body movements. To achieve this, a Six-Port interferometer is used to measure the heart sound envelogram of a test person from which subsequently the respiration can be reconstructe

RF Built-In Self-Test for Integrated Cellular Transmitters - Münker, Christian; Weigel, Robert (ANALOG 2006 - 9. ITG/GMM-Fachtagung, 2006)
A spectral built-in self test (BIST) solution for integrated cellular RF transmitters is presented that enables on-chip verification of PLL spectral performance. Multi-tone FM test signals with a spurious-free dynamic range (SFDR) of 60 dB are generated without compromising the performance of the RF transmitter itself. The RF signal is demodulated and digitized in an on-chip digital FM discriminator, spectral analysis is performed using digital narrowband filtering. The additional BIST blocks are fully digital and have been implemented on a chip area of only 0.05 mm2 in a 130 nm CMOS technology. The test blocks allow fast measurement of PLL frequency response, level of spurious sidebands and in-band phase noise down to -80 dBc without external test equipment. Catastrophic faults and most parametric faults can be detected as long as they influence the loop bandwidth or deteriorate spectral performance.
elib2cris::1512001600,muenker2006d

RF built-in self-test for integrated cellular transmitters - Münker, Christian; Weigel, Robert (Conference for Design, Automation and Test in Europe, 2007)
elib2cris::1512001600,muenker2007

RF Built-In Self-Test for Integrated Transmitters Using Sigma-Delta Techniques - Münker, Christian; Weigel, Robert (ITG/GMM Workshop "Testmethoden und Zuverlässigkeit 2006" Titisee, Germany, 2006)
A new approach to adding built-in self test (BIST) capabilities to integrated sigma-delta modulation RF transmitters is presented. An area efficient, all-digital building block generates multitone FM stimulus signals without compromising the performance of the RF transmitter itself. The RF signal is demodulated and digitized in a on-chip digital FM discriminator. Both blocks are fully testable using standard scan chain methods and consume a chip area of only 0.03 mm2 in a 130 nm CMOS technology. The spectral quality and reproducibility of the test signals are suitable for intermodulation distortion tests or PLL frequency response measurements.
elib2cris::1512001600,muenker2006b

RF Design of Systems For and Beyond Third-Generation Mobile Radio Communications - Springer, Andreas; Weigel, Robert (Proc. International Workshop on Emerging Personal Communications, 2002)
elib2cris::1512001600,springer2002c

RF Front-End Design for Software Defined Radio - Maurer, Linus; Weigel, Robert (Wireless World Research Forum, Helsinki, Finland, 2001)
Multimode, multiband transceivers were once seen as desirable but unachievable goal, particularly when considering small, battery-powered terminals. There are, however, significant market-pulls requiring just such a device and dual-mode systems (albeit with largely separate hardware) are now a reality. The next revolution will be the production of so-called flexible architecture terminals, in which the same hardware is used for all modulation formats and bands, with internal software determining the mode to be utilized [1]. The specifications required for each block and the upcoming technological advancements should be examined. Based on this approach, a realistic evaluation of architectures, that can handle the task, should be possible.
elib2cris::1512001600,maurer2001a

RF Frontends for Mobile Radio Terminal Applications - Tag, Andreas; Hagelauer, Amelie Marietta (IEEE Transactions on Microwave Theory and Techniques, 2016)
CRIS-Team Scopus Importer:2023-03-08

RF Front-End System Design for Location Based Services Applications - Miskiewicz, Anna; Holm, Andreas; Weigel, Robert (IEEE Radio and Wireless Symposium (RWS), 2006)
This paper presents feasibility studies for the implementation of a multi-standard, multimode RF frontend enabling utilization of Location Based Services (LBS) in a mobile handset using A-GPS system with GSM and UMTS support. A short description of the proposed system architecture is presented. The setup is proven based on the system simulations using Matlab. The influence of gain compression, wideband noise and reciprocal mixing on the system performance due to a full-duplex interferer is described. The analysis is extended for intermodulation test cases in a mobile environment. Feasibility analysis is confirmed with measurements of a GPS/Galileo/UMTS/CDMA2000/GSM reconfigurable front-end implemented in 130nm CMOS technology.
elib2cris::1512001600,miskiewicz2006
Keywords: 3G mobile communication; cellular radio

RFIC's for the Japanese UMTS Market - Thomann, Wolfgang; Fenk, Josef; Pretl, Harald; Hagelauer, Richard; Weigel, Robert (International Symposium on Acoustic Wave Devices, 2001)
elib2cris::1512001600,thomann2001

RFIC's for W-CDMA Mobile Terminal Applications: Current Status and Future Trends - Thomann, Wolfgang; Fenk, Josef; Pretl, Harald; Hagelauer, Richard; Weigel, Robert (Proc. IEEE International Workshop on Commercial Radio Sensing and Communication Techniques, 2001)
elib2cris::1512001600,thomann2001b

RFID and Wireless Sensing - Essel, Jochen; Brenk, Daniel; Weigel, Robert (SENSOR+TEST 2009, 2009)
The efforts in realizing ubiquitous integrated circuits for ambient intelligence networks increased over the past few years. In particular, the passive radio frequency identiﬁcation (RFID) presents a key technology for unattended wireless networks. A typical state of the art passive RFID system consists of an interrogator/reader and several passive Transponders. The interrogator communicates with the transponders by a wireless peer-to-peer connection and is responsible for the power supply of the passive transponders. To achieve a higher reading range and to improve the operational reliability of passive RFID sensor tags, the design of integrated circuits with an ultra low-power consumption and novel concepts for high-efﬁciency energy scavenging are required.
elib2cris::1512001600,essel2009b
Keywords: RFID; radio frequency identiﬁcation; sensor networks; wireless sensing; ubiquitous networks; ADC

RFID at UHF Frequencies: The Passive Transponder Frontend Approach - Seemann, Kay; Cilek, Fatih; Schmidt, Matthias; Weigel, Robert (International Conference on Microwaves, Radar & Wireless Communications, 2006)
In order to improve the operational reliability of passive backscattering RFID (radio frequency identification) transponders, the design of low-loss integrated circuits and the implementation of novel concepts for efficient energy scavenging are an emerging task. This article deals with general considerations regarding self-sustaining transponder devices using the RF power rectification approach and the backscatter modulation technique. We present important fundamentals and limitations of the passive integrated RF frontend architecture.
elib2cris::1512001600,seemann2006a

RFIDs – Anwendungen und Technologien - Seemann, Kay; Weigel, Robert (EEEfCOM, 2004)
UnivIS-Import:2015-04-16:Pub.2004.tech.IE.LETE.rfidsa

RFID System Read Range in Automotive Assembly Lines - Iliev, Stoyan; Vinci, Gabor; Luy, Johann-Friedrich (EEEfCOM 2007, 2007)
elib2cris::1512001600,iliev2007a

RF MEMS and NEMS technology, devices, and applications - Fischer, Georg; Gammel, P.; Bouchaud, J. (Bell Labs Technical Journal, 2005)
Will RF MEMS deliver on its promise to be one of the major MEMS businesses in the future? RF MEMS has now entered its second generation; high-volume production of both contacting and non-contacting switches and filters (based on bulk acoustic waves) was ramped up worldwide starting in 2003. In first-generation RF MEMS, discrete components were developed to demonstrate RF performance and reliability, and low-cost, high-volume chipand wafer-scale packaging eliminated the final barriers to high-volume production of discrete replacement components with MEMS. In this paper, we review the RF MEMS industry and the commercialization status of RF MEMS components. We also provide a detailed case study of mobile telephone basestations, demonstrating how RF MEMS can impact telecommunications. Finally, we look at research into third-generation RF MEMS and NEMS, in which integration, active devices, and new functionality will create opportunities for disruptive changes in RF subsystems, enabling such things as software-defined radio. © 2005 Lucent Technologies Inc.
elib2cris::1512001600,fischer2005c

RF MEMS Applications for Wireless Communication Systems - Fischer, Georg (MEMS-Seminar im DFG-Graduiertenkolleg "Mischfelder und nichtlineare Wechselwirkungen", 2003)
As with communication systems spectrum is the most scare resource, there is great demand for flexible radios that can adapt to different frequency bands of operation to accommodate regulatory changes or facilitate new methods for spectrum pooling. The classical answer to this demand has been the software radio approach based on wideband sampling techniques. In the talk an alternative solution to provide flexibility with respect to frequency band of operation and channel bandwidth is given that is based on RF-MEMS. For this approach a new terminology is settling in literature which is the "frequency agile radio" or more precisely the "frequency agile frontend". It shows up that RF-MEMS is a very attractive technology to provide the requested flexibility through reconfiguring the properties of the RF chain. A comparison between the classical approach of providing flexibility solely through alterations in the digital domain after wideband sampling versus the new approach of altering the characteristics of the RF chain prior to narrowband sampling is provided. The pros and cons will be listed and weighted. Some examples for the use of RF-MEMS for flexibility in the analog RF domain will be given: - Reconfigurable basestations - Wireless microphone systems - Terminals (mobile phones/data cards), interfacing between power amplifier and integrated antenna - Adaptive matching with reconfigurable Multiband Power amplifiers The talk will highlight that tuning elements offered through RF-MEMS devices like Switches, Varactors (variable C) and Variometers (variable L) will allow for new radio architectures that allow for great flexibility at low cost. Packaging and integration issues will also be addressed from the system perspective.
elib2cris::1512001600,fischer2003

RF-MEMS as the bridge between digital control and high performance analog RF - Fischer, Georg (German Microwave Conference (GeMiC 2006) , Karlsruhe, Germany, 2006)
elib2cris::1512001600,fischer2006c

RF-MEMS benefits for the RF system of wireless basestations - Fischer, Georg (Advanced MEMS for RF and Millimeter Wave Communications - European Networks, 2006)
elib2cris::1512001600,fischer2006g

RF-MEMS for basestations, talk and panel discussion "Will RF MEMS hold its promises?" - Fischer, Georg (Electronica Trade Fair, 2006)
elib2cris::1512001600,fischer2006h

RF MEMS for ubiquitous wireless connectivity. Part I. Fabrication - Fischer, Georg; De Los Santos, Hector; Tilmans, Harrie; van Beek, Joost (IEEE Microwave Magazine, 2004)
The aim of this article to expose the impact and status of the application of RF-MEMS switchable capacitors, varactors and switches in the three elements of this paradigm, namely, handsets, base stations, and satellites. In particular, issues such as system-level motivation/justification for RF MEMS, device requirements, high-volume manufacturing, packaging, and state-of-the-art performance and reliability, are presented.
elib2cris::1512001600,fischer2004b

RF MEMS for ubiquitous wireless connectivity. Part II. Application - Fischer, Georg; De Los Santos, Hector; Tilmans, Harrie; van Beek, Joost (IEEE Microwave Magazine, 2004)
This paper reports on RF-MEMS switchable capacitors, varactors, and ohmic switch technology attribute for both base stations and handsets in realizing frequency-agile RF/wireless systems capable of serving multiple frequency bands. For the handset, this leads to a smaller footprint combined with low power consumption of the RF radio. For the base station the benefit lies in ability for reconfiguration of the air interface, which leads to high logistical savings for infrastructure vendors through a reduction in the number of product variants. Reconfigurable frequency-agile radios are a perfect addition to reconfigurable baseband processing. Both together form the basis of a realistic and reasonable approach to realize software radio
elib2cris::1512001600,fischer2004c

RF MEMS Modules: A Multiphysical Design Methodology Based on System Performance Requirements - Silva Cortes, Victor Arturo; Nowak, Jacek; Chauhan, Vikrant; Stehr, Uwe; Hein, Matthias A.; Fischer, Georg; Hagelauer, Amelie Marietta (IEEE Microwave Magazine, 2019)
CRIS-Team Scopus Importer:2019-09-24

RF Microelectronics for W-CDMA Mobile Communication Systems - Springer, Andreas; Weigel, Robert (Electronic Communications Engineering, 2002)
Third generation (3G) mobile communication systems are now just starting to be introduced. With a maximum data rate of 2 Mbit/s they will make wireless access to broadband data services like the Internet or video applications feasible. Most of the different physical layer technologies summarised under the acronym 3G are based on wideband-CDMA (W-CDMA), in contrast to existing second generation systems, which mostly use TDMA and FDMA. This has severe consequences for the design of the transceiver front-ends. During standardisation these were assumed to have an adequate RF performance yet they still present a performance bottleneck for the system. Starting with a short introduction to UMTS (Universal Mobile Telecommunications System)-the 3G standard to be deployed in Europe and already operating in Japan-this paper describes by way of example some of the test cases specified for UMTS and their impact on the analogue front-end. It is shown that accurate simulation of all the analogue and digital signal processing is necessary in order to predict the RF performance needed of today's commercial RFICs. The paper then presents and reviews some actual design examples. Finally, possible technologies and techniques for application in future mobile terminals are discussed.
elib2cris::1512001600,springer2002d
Keywords: 3G; W-CDMA

RF Switch Design for Reconfigurable Power Amplifiers with High Back-off Efficiency in nm-CMOS Technologies - Rascher, Jochen (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2015)

RF System Concepts for Highly Integrated RFICs for W-CDMA Mobile Radio Terminals - Springer, Andreas; Maurer, Linus; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2002)
The standardization phase for third-generation wide-band CDMA systems like the universal mobile telecommunication system, which will add broad-band data to support video, Internet access, and other high-speed services for untethered devices is running toward its finalization. As is typical for mobile communication systems standardization, sufficient RF performance has been assumed and most efforts have been put to digital baseband issues. This is especially true for the mobile phone transceivers, the RF part of which is (although its baseband part is much more complex in terms of number of devices) still the bottleneck of the entire system. Meanwhile, in the RF concept engineering of today’s commercial products, an accurate prediction of the needed RF performance by using RF system simulation is indispensable. This is, in particular, the case with third-generation wireless systems, which, from the RF design point-of-view, are quite different from second-generation time-division multiple access/frequency- ivision multiple-access systems due to the fact that the user signals are now separated in the code domain rather than in the time and/or frequency domain. The paper gives an insight of how to derive receiver requirements for third-generation mobiles in terms recognizable by microwave designers, reports on the system simulation-based design, and performance of silicon-based RF integrated circuits for mobile terminal use, and discusses some future technologies and techniques and their possible impact on portable wireless Devices.
elib2cris::1512001600,springer2002b
Keywords: CDMA; RFIC

RF Systems for SDR Basestations with Wide Frequency Agility and Highly Energy Efficient - Fischer, Georg (Bell Labs Colloquium, 2008)
elib2cris::1512001600,fischer2008

RF transceiver architectures for W-CDMA systems like UMTS: State of the art and future trends - Weigel, Robert; Maurer, Linus; Pimingsdorfer, Dieter; Springer, Andreas (International Symposium on Acoustic Wave Devices, 2001)
elib2cris::1512001600,weigel2001a

Rigorous Modeling of Parasitic Effects in Complex SAW RF-Filters - Fischerauer, Gerhard; Gogl, Dietmar; Weigel, Robert; Russer, Peter (Microwave Symposium Digest, 1994)
This work presents an easy-to-implement and fast lumped-element circuit model for the parasitics of complex low-loss surface acoustic wave (SAW) devices such as interdigitated interdigital transducer (IIDT) and image impedance connected (IIC) filters. The model parameters can be derived from knowledge of the device geometry without recourse to optimization methods. We investigated the influence of the measurement setup, the package and the layout itself. It is shown how the model parameters are determined by either experiment or analysis. The greatly enhanced predictive power of the extended simulation model is demonstrated by applying it to a 15-transducer IIDT filter and a 22-transducer IIC filter at 900 MHz. It was found, for instance, that parasitic capacitances strongly influence the input impedance in the passband while the stopband level is easily explained by the inductive coupling between bond wires
elib2cris::1512001600,fischerauer1994

Risikominimierung im Wertschöpfungs- und Innovationsprozess von hochkonfigurierbaren elektronischen Systemenmittels modifizierter FMEA und Ableitung relevanter Entwicklungsparameter - Wittmann, Armin (Friedrich-Alexander-Universität Erlangen-Nürnberg, 2009)

Robust and Efficient W-LAN Systems for Very High Data Rates Employing Single Carrier Transmission with Frequency Domain Equalization - Witschnig, Harald; Koppler, Alois; Springer, Andreas; Weigel, Robert (Proc. Wireless World Research Forum, 2002)
elib2cris::1512001600,witschnig2002

Robust Beamforming for SWIPT Systems with Non-linear Energy Harvesting Model - Boshkovska, Elena; Kölpin, Alexander; Kwan Ng, Derrick Wing; Zlatanov, Nikola; Schober, Robert (IEEE 17th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2016)
This paper investigates resource allocation for simultaneous wireless information and power transfer (SWIPT) downlink systems based on a non-linear energy harvesting model. The resource allocation algorithm design is formulated as a non-convex optimization problem for the maximization of the total harvested power. The proposed problem formulation not only takes into account imperfect channel state information (CSI) but also guarantees the quality-of-service (QoS) of information transfer. A novel iterative algorithm is proposed to obtain the globally optimal solution of the considered non-convex optimization problem. In each iteration, a rank-constrained semidefinite program (SDP) is solved optimally by SDP relaxation. Simulation results demonstrate the significant gains in harvested power and the robustness against CSI imperfection for the proposed optimal resource allocation, compared to a baseline scheme designed for perfect CSI and the conventional linear energy harvesting model.
elib2cris::1512001600,boshkovska2016
Keywords: Energy Harvesting; Diode Detector

Robust Correlation based True-Speed-over-Ground Measurement System employing a FMCW Radar - Reißland, Torsten; Lenhart, Björn; Lichtblau, Johann; Sporer, Michael; Weigel, Robert; Kölpin, Alexander (2018 15th European Radar Conference (EuRAD), 2018)
This paper presents a novel approach for the determination of True-Speed-Over-Ground for trains. Speed determination is accomplished by correlating the received signals of two side-looking radar sensors. The theoretically achievable precision is derived. Test measurements are done to give a prove of concept. The measurements are done in two different scenarios. The test measurements are carried out using a bi-static 24 GHz frequency modulated continuous wave (FMCW) rada
Keywords: radar; fmcw; correlation; sar; velocity; train

Robust MSE-Balancing Hierarchical Linear/Tomlinson-Harashima Precoding for Downlink Massive MU-MIMO Systems - Zarei, Shahram; Gerstacker, Wolfgang; Weigel, Robert; Vossiek, Martin; Schober, Robert (IEEE Transactions on Wireless Communications, 2018)
In this paper, we propose a robust minimum maximum mean square error Tomlinson-Harashima precoding (Min-Max-MSE THP) scheme and a low-complexity robust Min-Max-MSE hierarchical linear/THP (HL-THP) scheme for downlink massive multiuser multiple-input-multiple-output (MU-MIMO) systems with imperfect channel state information (CSI) at the transmitter. The proposed robust Min-Max-MSE HL-THP scheme comprises an inner linear beamformer (BF), which is designed based on second-order CSI statistics, and outer THP modules, which exploit the instantaneous overall CSI of the cascade of the actual channel and the inner BF. Thereby, the user terminals are divided into groups, where for each group a THP module successively mitigates the intra-group interference, whereas the inter-group interference is canceled by the inner BF. To ensure fairness, we adopt the maximization of the asymptotic signal-to-leakage-plus-noise ratio in the large system limit and the Min-Max-MSE as an optimization criterion for designing the inner BF and the per-group THP modules, respectively. Our analytical and simulation results show that the proposed robust Min-Max-MSE HL-THP scheme achieves a substantially improved performance in terms of the Max-MSE, maximum bit error rate, and minimum rate compared to linear regularized zero-forcing precoding. Moreover, the performance loss of the proposed robust Min-Max-MSE HL-THP scheme compared to the robust Min-Max-MSE THP scheme is small. In addition, our complexity analysis reveals that the proposed robust Min-Max-MSE HL-THP scheme has a much lower computational complexity than the Min-Max-MSE THP scheme. Hence, the robust Min-Max-MSE HL-THP scheme provides a favorable tradeoff between complexity and performanc
lhft_intern.bib::Zarei2018a
Keywords: Precoding; Robustness; Interference; Computational complexity; Optimization; Wireless communication

Robust Permittivity Reconstruction With the Transmission and Reflection Method at mm-Wave Frequencies - Kornprobst, Simon; Engelsberger, Franz Xaver; Wojnowski, MacIej; Weigel, Robert (IEEE Transactions on Microwave Theory and Techniques, 2023)
The permittivity reconstruction with the transmission and reflection method usually requires time-gating to mitigate distorted measurement data. State-of-the-art approaches reduce the available bandwidth as they introduce ringing. Available frequency extension approaches to avoid a bandwidth reduction are not based on a physically meaningful estimate. In this work, we propose a method that takes advantage of the information already given by the measurement to calculate a reasonable frequency extension. The inverse problem of the actual permittivity reconstruction is most commonly approached by the Baker-Jarvis algorithm from the National Institute of Standards and Technology (NIST) which considers the magnitude of one single complex number. It is calculated from the difference between measurement and model of the scattering matrix. In this article, we demonstrate the superiority of matching all four scattering parameters individually instead. This results in particular in a wider range of initial start parameters with proper convergence to the desired solution and more reliable reconstruction results for optimizations with unknown sample thickness. The benefits of the novel reconstruction techniques are demonstrated and evaluated in detail on simulation and measurement data in the V band.
CRIS-Team Scopus Importer:2023-12-22
Keywords: Generalized Baker-Jarvis; scattering parameters; time-gating; waveguide measurement

Robust Radar-Based Vital Sensing With Adaptive Sinc Filtering and Random Body Motion Rejections - Hazra, Souvik; Fusco, Alessandra; Kiprit, Gamze Naz; Stadelmayer, Thomas; Habib, Sarfaraz; Servadei, Lorenzo; Wille, Robert; Weigel, Robert; Santra, Avik (IEEE Sensors Letters, 2023)
In this letter, we propose a noncontact vital sign monitoring algorithm based on 60-GHz frequency modulated continuous wave (FMCW) radar. At the heart of the algorithm is a bank of sinc filters covering the heart and respiratory frequencies of an healthy adult. The filter bank is adapted, in successive iterations, to the specific cardiorespiratory frequencies of the monitored subject. The adaptability of the algorithm ensures an accurate estimate of heart rate (HR) and respiratory rate (RR) for a subject sitting in front of the radar at a distance between 0.3 to 1.1 m while being robust to minor body movements and harmonics. The efficiency of the solution is demonstrated on an experimental dataset including recordings of ten subjects, where we obtain an root mean square error (RMSE) of 6.16 bpm for HR and 2.09 rpm for RR.
CRIS-Team Scopus Importer:2023-05-19
Keywords: frequency modulated continuous wave (FMCW radar); heart rate (HR); remote monitoring; respiratory rate (RR); sensor applications; Sensor signal processing; vital signs

Robust Resource Allocation for MIMO Wireless Powered Communication Networks Based on a Non-Linear EH Model - Boshkovska, Elena; Wing Kwan Ng, Derrick; Zlatanov, Nikola; Kölpin, Alexander; Schober, Robert (IEEE Transactions on Communications, 2017)
In this paper, we consider a multiple-input multiple-output wireless powered communication network, where multiple users harvest energy from a dedicated power station in order to be able to transmit their information signals to an information receiving station. Employing a practical non-linear energy harvesting (EH) model, we propose a joint time allocation and power control scheme, which takes into account the uncertainty regarding the channel state information (CSI) and provides robustness against imperfect CSI knowledge. In particular, we formulate two non-convex optimization problems for different objectives, namely system sum throughput maximization and the maximization of the minimum individual throughput across all wireless powered users. To overcome the non-convexity, we apply several transformations along with a one-dimensional search to obtain an efficient resource allocation algorithm. Numerical results reveal that a significant performance gain can be achieved when the resource allocation is designed based on the adopted non-linear EH model instead of the conventional linear EH model. Besides, unlike a non-robust baseline scheme designed for perfect CSI, the proposed resource allocation schemes are shown to be robust against imperfect CSI knowledge.<br
Keywords: Resource management; Wireless communication; Algorithm design and analysis; Robustness; Power generation; Throughput; Radio frequency

Robust Time and Frequency Synchronization for OFDM Systems with Maximum Spectrum Flexibility - Blümm, Christian; Heller, Christoph; Weigel, Robert (IEEE Topical Conference of Antennas and Propagation in Wireless Communications, 2012)
elib2cris::1512001600,bluemm2012a

Role of metal electrodes in the generation of third order non-linearities in Surface Acoustic Wave Components - Chauhan, Vikrant; Mayer, Markus; Ruile, Werner; Wagner, Karl; Weigel, Robert; Mayer, Andreas; Hagelauer, Amelie Marietta (IEEE International Ultrasonics Symposium 2017, 2017)
The growing complexity in RF front-ends, which support carrier aggregation and a growing number of frequency bands, leads to tightened nonlinearity requirements in all sub-components. The generation of third order intermodulation products (IMD3) are typical problems caused by the non-linearity of SAW devices. In the present work, we investigate temperature compensating (TC) SAW devices on Lithium Niobate-rot128YX. An accurate FEM simulation model [1] is employed, which allows to better understand the origin of nonlinearities in such acoustic devices.
Keywords: SAW; Intermodulation products; Nonlinear

Role of metal electrodes in the generation of third-order nonlinearities in TC-SAW devices - Chauhan, Vikrant; Mayer, Markus; Mayer, Elena; Ruile, Werner; Ebner, Thomas; Bleyl, Ingo; Mayer, Andreas; Wagner, Karl; Weigel, Robert; Hagelauer, Amelie Marietta (IEEE International Ultrasonics Symposium, IUS, 2017)
The growing complexity in RF front-ends, which support carrier aggregation and a growing number of frequency bands, leads to tightened nonlinearity requirements in all sub-components. The generation of third order intermodulation products (IMD3) are typical problems caused by the non-linearity of SAW devices. In the present work, we investigate temperature compensating (TC) SAW devices on Lithium Niobate-rot128YX. An accurate FEM simulation model [1] is employed, which allows to better understand the origin of nonlinearities in such acoustic devices.
CRIS-Team Scopus Importer:2023-03-08

Rotary Coupler in Microstrip Line Design for Data Transmission in the 2.45 GHz ISM Band - Scheiner, Benedict; Beck, Christopher; Lurz, Fabian; Frank, Martin; Michler, Fabian; Weigel, Robert; Kölpin, Alexander (International Microwave and Radar Conference (MIKON), 2020)

Roundtrip-Time-of-Flight Based Localization of Passive Multi-Standard RFID-Tags - Ußmüller, Thomas; Brenk, Daniel; Essel, Jochen; Heidrich, Jürgen; Fischer, Georg; Weigel, Robert (IEEE International Conference on Wireless Information Technologies and Systems, 2012)
elib2cris::1512001600,ussmueller2012a

RSSI-based Localization With Minimal Infrastructure Using Multivariate Statistic Techniques - Pflaum, Felix; Erhardt, Stefan; Weigel, Robert; Kölpin, Alexander (IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), 2017)
In this paper a new approach to localization of mobile nodes in wireless sensor networks is presented which utilizes the measurement of the received signal strength indicator by multiple receivers concentrated in a small area and applies the technique of linear discriminant analysis to the received data. The concept of gathering all receivers at a single spot provides great flexibility, while good spatial resolution is still achieved. This is demonstrated by a test network operating in the sub-GHz-range around 868 MHz.
elib2cris::1512001600,pflaum2017
Keywords: wireless; wsn; lda; statistics; localization

Salinity-Based Molecular Communication in Microfluidic Channels - Angerbauer, Stefan; Hamidović, Medina; Enzenhofer, Franz; Bartunik, Max; Kirchner, Jens; Springer, Andreas; Haselmayr, Werner (IEEE Transactions on Molecular, Biological and Multi-Scale Communications, 2023)
In this work, we present a novel portable, flexible and easy-to-use experimental setup for investigating salinity-based information transmission in microfluidic channels. At the receiver, the different salinity-levels are detected by a customized electronic circuit, which measures electrical conductivity via electrodes in the microfluidic channel. We provide a detailed description of the setup, including the microfluidic chip fabrication. Moreover, we develop a rigorous mathematical model of each testbed component and an end-to-end model of the system, which we have verified through experiments. Finally, we analyzed the error performance of the setup using optimum and sub-optimum detection algorithms, such as the Viterbi algorithm and threshold detecti
Keywords: molecular communication; testbed; microfluidics

Sampling rate impact on energy consumption of biomedical signal processing systems - Tobola, Andreas; Streit, Franz-Josef; Espig, Chris; Korpok, Oliver; Leutheuser, Heike; Sauter, Christian; Lang, Nadine; Schmitz, Björn; Hofmann, Christian; Struck, Matthias; Weigand, Christian; Eskofier, Björn; et al. (12th International Conference on Wearable and Implantable Body Sensor Networks (BSN), 2015)
UnivIS-Import:2016-06-01:Pub.2015.tech.IMMD.IMMD5.sampli

SAW and CMOS RFID Transponder-based Wireless Systems and their Applications - Hagelauer, Amelie Marietta; Ußmüller, Thomas; Weigel, Robert (IEEE International Frequency Control Symposium, 2012)
elib2cris::1512001600,hagelauer2012

Saw-Based Radio Sensor and Communication Techniques - Seifert, Franz; Weigel, Robert (27th European Microwave Conference, 1997)
Surface acoustic waves can be generated at the free surface of an elastic solid. This phenomenon has been exploited for electronic analog signal processing over the past 30 years, with the development of a host of devices and systems for consumer, commercial and military applications running at a some hundred million dollar annual rate. The objective of this paper is to provide an overview of the latest developments in the surface acoustic wave (SAW) field and to identify upcoming applications in remote sensing and communications. It. is intended to address some of the key issues in the successful design and manufacture of SAW devices and to discuss the operating principles from a microwave design viewpoint.
elib2cris::1512001600,seifert1997

SAW-Based Radio Sensor Systems - Reindl, Leonhard; Pohl, Alfred; Scholl, Gerd; Weigel, Robert (IEEE Sensors Journal, 2001)
Surface acoustic wave (SAW) devices can be used as identification and sensor elements (SAW transponders) for measuring physical quantities such as temperature, pressure, torque, acceleration, humidity, etc., that do not need any power supply and may be accessed wirelessly. The complete wireless sensor system consists of such a SAW transponder and a local radar transceiver. An RF burst transmitted by the radar ransceiver is received by the antenna of the SAW transponder. The passive transponder responds with an RF signal—like a radar echo—which can be received by the front-end of the local transceiver. Amplitude, frequency, phase and time of arrival of this RF response signal carry information about the SAW reflection and propagation mechanisms which in many cases can be irectly attributed to the sensor effect for a certain measurand. Usually no intersymbol interference (ISI) due to environmental choes occur, due to the high delay time of the SAW transponder in the order of some s. The present work reviews the operating rinciples of such sensor systems and their state-of-the-art performance by way of some examples which include the wireless easurement of temperature, pressure, torque, acceleration, tire-road friction, magnetic field, and water content of soil.
elib2cris::1512001600,reindl2001
Keywords: Acceleration; local radar transceiver; magnetic field; passive SAW transponder for sensing; pressure; temperature

SAW-based radio sensor systems for short-range applications - Scholl, Gerd; Korden, Christian; Riha, Evelyn; Ruppel, Clemens; Wolff, Ulrich; Riha, Gerd; Reindl, Leonhard; Weigel, Robert (IEEE Microwave Magazine, 2003)
Wireless autonomous surface acoustic wave (SAW) sensors offer high flexibility for modern sensor systems. Because no battery or wiring is required for power-supply and communication tasks, they can be advantageously employed for nearly all kinds of short-range identification and measurement applications, where the use of conventional sensors, e.g., on moving or rotating parts or in industrial process chambers. Here, the basics of SAW-based radio sensor systems are reviewed and different examples out of a manifold of possible applications are given. Wireless SAW identification and sensor systems operate stable and maintenance free over many years even in harsh industrial environments. With a fast readout of only a few microseconds, a readout-distance of up to several meters, and a high sensor stability, even at temperatures above 200 deg;C, these highly flexible SAW-based radio systems are ideally suited for a multitude of measurement tasks in industrial, automotive, transportation, and domestic applications.
elib2cris::1512001600,scholl2003a
Keywords: 200 C; IDT; SAW identification; SAW-based radio sensor systems; industrial process chambers; interdigital transducer; power supply; short-range applications; short-range identification; short-range measurement; surface acoustic wave; wireless autonomous SAW sensors; interdigital transducers; remote sensing; surface acoustic wave sensors

SAW-based radio sensor systems for short-range applications - Scholl, Gerd; Reindl, Leonhard; Ruppel, Clemens; Weigel, Robert (Radio and Wireless Conference, 2003. RAWCON '03. Proceedings, 2003)
Wireless autonomous surface acoustic wave (SAW) sensors offer highest flexibility for modern sensor systems. Because no battery or wiring is required for power-supply and communication tasks they can advantageously be employed for nearly all kinds of short-range identification and measurement applications, where the use of conventional sensors is comfortable, impossible or dangerous, e.g. on moving or rotating parts or in industrial process chambers. In the present work the basics of SAW-based radio sensor systems are reviewed and different examples out of a manifold of possible applications will be given.
elib2cris::1512001600,scholl2003
Keywords: measurement application; radio sensor system; short-range identification; surface acoustic wave sensors; wireless autonomous SAW sensors; surface acoustic wave sensors; wireless sensor networks

SAW-basierte Signalanalyse zur Online-Fehlererkennung - Jungwirth, Mario; Novak, Dieter; Pimingsdorfer, Dieter; Weigel, Robert (Proc. Projektentwicklung und Durchfuehrung eines Referenzprojektes fuer das geplante Kompetenzzentrum fuer Mechatronik und Automation, 1999)
elib2cris::1512001600,jungwirth1999

SAW Chirp Filter und ihre Anwendung in der Funkkommunikation - Huemer, Mario; Pohl, Alfred; Gugler, Wolfgang; Springer, Andreas; Weigel, Robert; Seifert, Franz (48. Jahrestagung der Oesterreichischen Physikalischen Gesellschaft (OePG) - Fachtagung Akustik, 1998)
elib2cris::1512001600,huemer1998a

SAW Devices and Their Microwave Applications - Weigel, Robert; Morgan, David; Owens, John; Ballato, Art; Lakin, Kenneth; Hashimoto, Ken-ya; Ruppel, Clemens (IEEE Microwave Magazine, 2002)
Due to the superior performance of SAW filters, combined with additional features, e.g., impedance transformation, balun functionality, and integration of two or even three filter functions into one package, SAW filters have become the key components in mobile communication and multimedia applications. More cost-effective and miniaturized designs are effectively supported by reducing overall component count and PCB space used.
elib2cris::1512001600,weigel2002c
Keywords: SAW; Communication

SAW devices and their wireless communications applications - Ruppel, Clemens; Reindl, Leonhard; Weigel, Robert (IEEE Microwave Magazine, 2002)

SAW device testing based on estimation methods - Johnson, John; Weigel, Robert (Kleinheubacher Tagung, 1996)
elib2cris::1512001600,johnson1996

SAW-Filter, Hochfrequenz- und Zwischenfrequenzteil eines TCDMA-Breitbandsystems (Downlink) - Zenzinger, Alesander; Seifert, Franz; Weigel, Robert (DFG-Kolloquium Mobilkommunikation, 1997)
elib2cris::1512001600,zenzinger1997

SAW fixed-code matched filters for wireless spread spectrum consumer communications - Weigel, Robert; Knorr, C.; Kalabic, Faris; Seifert, Franz; Wagner, Karl Christian; Reindl, Leonhard (European Microwave Conference, 1996)
elib2cris::1512001600,weigel1996e

SAW Microstrip Antenna-Duplexer for Radio Communication Transceivers in the GHz Range - Meier, Hans; Weigel, Robert; Anemogiannis, Kimon; Russer, Peter (21st European Microwave Conference, 1991, 1991)
Design, fabrication and performance of a SAW microstrip front-end circuit at 1.7 GHz for applications in time division multiple access (TDMA) systems are reported. The front-end consists of a transmitter part (containing a SAW filter for noise suppression and amplifiers), a receiver part (containing a stripline filter for preselection, a SAW filter, and a low noise amplifier), and a duplexing circuit. Both the transmitter SAW filter and the receiver SAW filter are low-loss filters with a center frequency of 1.684 GHz. The substrate material used for the SAW filters is 36rot YX-LiTaO3 and the acoustic wave type is a leaky surface acoustic wave (LSAW). The front-end operates at 1.684 GHz and has a 1 dB-bandwidth of 30 MHz with a pin-diode switch used in the duplexer. The output power at the antenna port is 23 dBm and the transmitter-receiver isolation is better than 50 dB. The present work arose from a requirement of a miniature low-cost front-end for digital cordless telephone systems. The paper also presents some new design and fabrication techniques for low-loss SAW filters in the upper UHF band.
elib2cris::1512001600,meier1991
Keywords: Circuit noise; Fabrication; Low-noise amplifiers; Transceivers; Time division multiple access; Microstrip antennas; Radio transmitters; SAW filters

SAW Microstrip Front-End for Mobile Communication Systems in the GHz Range - Anemogiannis, Kimon; Russer, Peter; Weigel, Robert; Zimmermann, C. (IEEE MTT-S International Microwave Symposium Digest, 1991, 1991)
The design, fabrication, and performance of a SAW (surface acoustic wave) microstrip front-end circuit in the low GHz range for applications in time division multiple access systems are reported. The front-end consists of a transmitter part (containing a SAW filter for noise suppression, and amplifiers), a receiver part (containing a stripline filter for preselection, a SAW filter, and a low-noise amplifier), and a duplexing circuit. Both the transmitter SAW filter and the receiver SAW filter are low-loss filters with a center frequency of 1.684 GHz, a fractional 3 dB-bandwidth of 3.5% and an insertion loss of 6 dB. The front-end operates at 1.684 and has 1 dB-bandwidth of 30 MHz. The output power at the antenna port is 23 dBm.<>
elib2cris::1512001600,anemogiannis1991
Keywords: mobile communication systems; strip line components; surface acoustic wave filters; time division multiple access; 1.684 GHz; mobile communication systems; low-noise amplifier; low-loss filters

SAW programmable and fixed-code matched filters for CDMA mobile radio applications - Weigel, Robert; Reindl, Leonhard; Seifert, Franz (Progress in Electromagnetics Research Symposium (PIERS), 1997)
elib2cris::1512001600,weigel1997

SAW propagation in periodic arrays including temperature effects - Wallner, Paul; Ruile, Werner; Weigel, Robert (IEEE Ultrasonics Symposium 1999, 1999)
In order to calculate the temperature behavior of SAW propagation in infinite periodic arrays a numerical procedure was established improving the theory of previous studies. This theory is based upon the orthogonal integration method. Improvements include a consideration of the mass loading effect due to the metal grating, a better numerical performance of the software and full access for calculations in the frequency range of both, stopband and conversion. Including the temperature dependence calculations were performed for quartz and LiTaO 3 leaky-SAW crystal cuts. The temperature behavior of stopband center frequency and width, attenuation, and onset-frequency was investigated and compared to results obtained for homogenous structures
elib2cris::1512001600,wallner1999b
Keywords: SAW

Scalable and Energy-Efficient Millimeter Massive MIMO Architectures: Reflect-Array and Transmit-Array Antennas - Jamali, Vahid; Tulino, Antonia M.; Fischer, Georg; Muller, Ralf; Schober, Robert (ICC 2019 - 2019 IEEE International Conference on Communications (ICC), 2019)
Hybrid analog-digital architectures are considered as promising candidates for implementing millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems since they enable a considerable reduction of the required number of costly radio frequency (RF) chains by moving some of the signal processing operations into the analog domain. However, the analog feed network, comprising RF dividers, combiners, phase shifters, and line connections, of hybrid MIMO architectures is not scalable due to its prohibitively high power consumption for large numbers of transmit antennas. Motivated by this limitation, in this paper, we study novel massive MIMO architectures, namely reflect-array (RA) and transmit-array (TA) antennas. We show that the precoders for RA and TA antennas have to meet different constraints compared to those for conventional MIMO architectures. Taking these constraints into account and exploiting the sparsity of mmWave channels, we design an efficient precoder for RA and TA antennas based on the orthogonal matching pursuit algorithm. Furthermore, in order to fairly compare the performance of RA and TA antennas with conventional fully-digital and hybrid MIMO architectures, we develop a unified power consumption model. Our simulation results show that unlike conventional MIMO architectures, RA and TA antennas are highly energy efficient and fully scalable in terms of the number of transmit antennas.<br
Keywords: Vehicular ad hoc networks; Taxonomy; Vehicle-to-infrastructure; Databases; Real-time systems

Scalable ECG Hardware and Algorithms for Extended Runtime of Wearable Sensors - Tobola, Andreas; Espig, Chris; Streit, Franz-Josef; Korpok, Oliver; Leutheuser, Heike; Schmitz, Björn; Hofmann, Christian; Struck, Matthias; Weigand, Christian; Eskofier, Björn; Fischer, Georg (2015 IEEE International Symposium on Medical Measurements and Applications, 2015)
Everything in nature tries to reach the lowest possible energy level. Therefore any natural or artificial system must have the ability to adjust itself to the changing requirements of its surrounding environment. In this paper we address this issue by an ECG sensor designed to be adjustable during runtime, having the ability to reduce the power consumption at cost of the informational content. Accessible for everyone, standard ECG hardware and open source software has been used to realize an ECG processing system for wearable applications. The average power consumption has been measured for each mode of operation. Finally we take conclusion to conciser context-aware scaling as key feature to address the energy issue of wearable sensor system
UnivIS-Import:2015-07-08:Pub.2015.tech.IMMD.IMMD5.scalab

Scalable Perceptual and Lossless Audio Compression Based on MPEG-4 AAC - Geiger, Ralf; Schuller, Gerald; Herre, Jürgen; Sporer, Thomas; et al. (115th AES Convention, 2003)
This paper presents a scalable lossless enhancement of MPEG-4 Advanced Audio Coding (AAC). Scalability is achieved in the frequency domain using the Integer Modified Discrete Cosine Transform (IntMDCT), which is an integer approximation of the MDCT providing perfect reconstruction. With this transform, and only minor extension of the bitstream syntax, the MPEG-4 AAC Scalable codec can be extended to a lossless operation. The system provides bit-exact reconstruction of the input signal independent of the implementation accuracy of the AAC core coder. Furthermore, scalability in sampling rate and reconstruction word length is supported.<br
Vorträge und Veröffentlichungen auf Konferenzen_Gehörangepasste Datenreduktion

Scenario-Based Energy Estimation of Heterogeneous Integrated Systems at System Level - Glock, Stefan; Rosales, Rafael; Reutelhuber, Franz; Glaß, Michael; Teich, Jürgen; Fischer, Georg; Weigel, Robert; Ußmüller, Thomas (Proc. 43rd European Microwave Conference, 2013)
One of the most important figures of merit concerning mobile devices is their energy efficiency. However, the modeling of such systems is mainly focused on the functional aspects, but not on the power consumption. Therefore, power estimations can only be accomplished late in the design process, after all architectural decisions have been taken. This might lead to designs that are not optimal with respect to power consumption. To overcome these limitations, this article proposes an efficient and flexible power modeling methodology at system level for heterogeneous integrated systems, allowing to combine state-dependent and environmental dependent power models. In a case study, the energy consumption of an RF transceiver of a mobile phone is estimated in a real-life scenario, including the baseband module, the radio channel, and the base transceiver station in a simulative way. © 2013 European Microwave Association.
elib2cris::1512001600,glock2013b

Scene-adaptive radar tracking with deep reinforcement learning - Stephan, Michael; Servadei, Lorenzo; Arjona-Medina, José; Santra, Avik; Wille, Robert; Fischer, Georg (Machine Learning with Applications, 2022)
Multi-target tracking with radars is a highly challenging problem due to detection artifacts, sensor noise, and interference sources. The traditional signal processing chain is, therefore, a complex combination of various algorithms with several tunable tracking-parameters. Usually, these are initially set by engineers and are independent of the scene tracked. For this reason, they are often non-optimal and generate poorly performing tracking. In this context, scene-adaptive radar processing refers to algorithms that can sense, understand and learn information related to detected targets as well as the environment and adapt its tracking-parameters to optimize the desired goal. In this paper, we propose a Deep Reinforcement Learning framework that guides the scene-adaptive choice of radar tracking-parameters towards an improved performance on multi-target tracking.<br