R. Weigel

Universitätsklinikum Erlangen, Erlangen, Bavaria, Germany

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Publications (760)207.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A new semi-physical memoryless computationally effective behavioral model (BM) capable of predicting amplitude-modulation-to-amplitude-modulation (AM–AM) and amplitude-modulation-to-phase-modulation (AM–PM) distortions is proposed. In recent years, AM–AM and AM–PM distortions have been separately studied in literature. Here, we investigate the correlation between AM–AM and AM–PM distortions first. Based on the observed correlation, a novel AM–PM model is derived from the well-known Rapp AM–AM model. On the basis of the close relationship between the AM–AM and AM–PM model, a highly accurate and computationally effective large-signal BM is obtained. The newly developed model addresses the current needs of the mobile industry that requires BMs of the power amplifier (PA), which can be interpreted by the designers. In addition, the models must be computationally effective due to the limited computation power in mobile handset. Therefore, only memoryless BMs can be taken into account and larger errors are accepted for the sake of computational effectiveness. In this paper, it is shown that the newly introduced model achieves excellent results, when it is applied to actual industrial applications of two GaAs-based class-AB PAs in 65-nm technology and one CMOS-based class AB PA in 28-nm technology, which are designed for mobile communications.
    IEEE Transactions on Microwave Theory and Techniques 06/2015; 63(6):1-10. DOI:10.1109/TMTT.2015.2418751 · 2.94 Impact Factor
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    ABSTRACT: Demographic shifts are part of the process of social and economic change that has been taking place worldwide over the last century. Europe is the first large subcontinent to encounter the effects of an aging society [1]. The same pattern is repeating in Latin America and Japan but with a quicker pace of transition compared with that which took place in the countries that are now industrialized [2]. This situation impacts the productivity and economic growth of the countries due to the reduction of the working age population [3]. Additionally, the increase in the number of elderly people who make use of service in the social security systems has a tremendous fiscal impact, which is represented in the expenses for pensions, health care, and longterm care. In addition, the increase of chronic diseases correlated with the lifestyle and the behavior in industrial countries (e.g., tobacco consumption, obesity, and the fact that the need for the primary care increases while the number of primary care providers diminishes) represent the challenges to be solved for the health systems of modern society [4].
    IEEE Microwave Magazine 05/2015; 16(4):71-86. DOI:10.1109/MMM.2015.2394024 · 1.67 Impact Factor
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    ABSTRACT: In this article, a lightweight, low-power radar system for vibration monitoring has been presented. Based on a theoretical analysis of the competition scenario, an optimized system concept has been developed. The radar front end is able to sequentially evaluate the in-phase and quadrature component of the received signal with only a single hybrid coupler and power detector, reducing the overall weight to 5 g including the power-supply cable. A low duty cycle of 1% allowed the power to average 1.5 mW. As the minimum required sensitivity was limited to 0.5-mm oscillation amplitude, the most challenging parts in this student competition were, in our opinion, the tight power and weight optimizations. As the competition required only vibration detection butno ranging, a minimalistic system concept optimized for this application was proposed. The system features a free-running VCO sourced directly from the power supply without any further stabilization. For ranging applications, temperature changes as well as supply and tuning voltage variations at the VCO could have a severe impact on the system's accuracy. However, for pure vibration detection of a well-defined target, this is not a problem. Further improvements could be achieved when designing a customized 24-GHz oscillator, optimized for high efficiency [9] and fast turn-on time. In addition, the necessary number of measurements per second could be further investigated. Currently, with ten measurements per second, there is a convenient safety margin against false detections; however, fewer measurements would directly reduce the duty cycle and thus the average power consumption of the system.
    IEEE Microwave Magazine 03/2015; 16(2):99-105. DOI:10.1109/MMM.2014.2367860 · 1.67 Impact Factor
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    ABSTRACT: In the following, a continuous wave radar system based on the Six-port principle will be shown for measurement tasks at enclosed systems needing micrometer accuracy as well as high update rates like tank level monitoring or hydraulic cylinder piston control. To exceed the ambiguity limit of such an interferometric system, a dual tone approach is used. The system will be presented with measurement results at 24 GHz within a WR42 waveguide to prove the feasibility of the proposed concept. Furthermore, considerations on timing will show the potential as a low-latency system, capable of high measurement data update rates, and different influences on the system performance and limitations of such a system will be discussed in comparison to alternative setups.
    International Journal of Microwave and Wireless Technologies 03/2015; DOI:10.1017/S1759078715000239 · 0.46 Impact Factor
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    ABSTRACT: A concept for a novel CMOS image sensor suited for analog image pre-processing is presented in this paper. As an example, an image restoration algorithm for reducing image noise is applied as image pre-processing in the analog domain. To supply low-latency data input for analog image preprocessing, the proposed concept for a CMOS image sensor offers a new sensor signal acquisition method in 2D. In comparison to image pre-processing in the digital domain, the proposed analog image pre-processing promises an improved image quality. Furthermore, the image noise at the stage of analog sensor signal acquisition can be used to select the most effective restoration algorithm applied to the analog circuit due to image processing prior to the A/D converter.
  • IEEE Topical Conference on Wireless Sensors and Sensor Networks, USA; 01/2015
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    ABSTRACT: An accurate characterization of microwave materials is essential for reliable high-frequency circuit design. This paper presents a measurement setup, which enables a quick and accurate determination of the relative permittivity of dielectric bulk materials up to 110 GHz. A ring-resonator is manufactured on a well-characterized substrate, serving as reference resonator. The material under test (MUT) is placed on top of the ring, which increases the effective permittivity and therefore introduces a shift of the resonance frequency of the resonator. In case of moderate to large dielectric losses of the MUTs, the quality factor of the resonator decreases perceptibly, which provides conclusions about the dielectric losses. Electromagnetic field simulations with different heights and relative permittivities of the MUTs provide a look-up table for the measured resonance frequencies. The functionality of the proposed measurement setup is validated by measurement results of different MUTs.
    International Journal of Microwave and Wireless Technologies 01/2015; DOI:10.1017/S1759078715000483 · 0.46 Impact Factor
  • IEEE Topical Conference on Wireless Sensors and Sensor Networks, USA; 01/2015
  • Source
    European Microwave Integrated Circuits (EuMIC), Rome, Italy; 10/2014
  • Proceedings of the 44th European Microwave Conference,, Rome, Italy; 10/2014
  • IEEE/MTT-S, Proceedings of the European Microwave Conference, Rome, Italy; 10/2014
  • European Microwave Conference; 10/2014
  • IEEE/MTT-S, Proceedings of the European Microwave Conference, Rome, Italy; 10/2014
  • European Microwave Conference; 10/2014
  • European Microwave Conference, Italy; 10/2014
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    ABSTRACT: This work presents a single- and dual-port fully integrated millimeter-wave ultra-broadband vector network analyzer. Both circuits, realized in a commercial ${hbox{0.35-}}mu{hbox {m}}$ SiGe:C technology with an $f_{t}/f_{max}$ of ${hbox{170/250 GHz}}$, cover an octave frequency bandwidth between 50–100 GHz. The presented chips can be configured to measure complex scattering parameters of external devices or determine the permittivity of different materials using an integrated millimeter-wave dielectric sensor. Both devices are based on a heterodyne architecture that achieves a receiver dynamic range of 57–72.5 dB over the complete design frequency range. Two integrated frequency synthesizer modules are included in each chip that enable the generation of the required test and local-oscillator millimeter-wave signals. A measurement $3sigma $ statistical phase error lower than 0.3$^{circ}$ is achieved. Automated measurement of changes in the dielectric properties of different materials is demonstrated using the proposed systems. The single- and dual-port network analyzer chips have a current consumption of 600 and 700 mA, respectively, drawn from a single 3.3-V supply.
    IEEE Transactions on Microwave Theory and Techniques 09/2014; 62(9):2168-2179. DOI:10.1109/TMTT.2014.2337264 · 2.94 Impact Factor
  • Robert Weigel
    IEEE Microwave Magazine 09/2014; 15(6):18-22. DOI:10.1109/MMM.2014.2333411 · 1.67 Impact Factor
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    ABSTRACT: This work presents a highly integrated transmitter (TX) and receiver (RX) chipset operating from 50 to 100 GHz. The local oscillator (LO) is realized using a high output power millimeter-wave integrated frequency synthesizer with an octave output frequency range. The proposed low-complexity discrete tuned synthesizer architecture employs a single wide-tuning range voltage-controlled oscillator core and a single-sideband mixer, which can be switched to operate as a LO amplifier. An ultra broadband variable gain amplifier, with a gain control range $>{hbox {25 dB}}$, is used at the output of the synthesizer to provide a tunable output power. A maximum output power from $+{hbox{7}}$ to $+{hbox{12 dBm}}$ and an output phase noise from $-{hbox{83}}$ to $-{hbox{96 dBc/Hz}}$ at 1-MHz offset are measured over the complete output frequency range. Moreover, a spurious suppression $>{hbox {22 dB}}$ is achieved over the entire synthesizer's tuning range. The RX shows a conversion gain $>{hbox {19 dB}}$ and a noise figure $< {hbox {9.5 dB}}$ from 50 to 100 GHz. The TX's measured saturated output power is from $ +{hbox{6}}$ to $-{hbox{1 dBm}}$ over the entire frequency range. The complete chipset is realized in a commercial low-cost SiGe:C technology with an $f- {t}/f_{max}$ of ${hbox{170/250 GHz}}$. Each of the TX and RX chips including the frequency synthesizers draw a current of 370 mA from a 3.3-V supply.
    IEEE Transactions on Microwave Theory and Techniques 09/2014; 62(9):2118-2131. DOI:10.1109/TMTT.2014.2337289 · 2.94 Impact Factor
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    ABSTRACT: In this paper, a detailed description of a synchronous field-programmable gate array implementation of a bilateral filter for image processing is given. The bilateral filter is chosen for one unique reason: It reduces noise while preserving details. The design is described on register-transfer level. The distinctive feature of our design concept consists of changing the clock domain in a manner that kernel-based processing is possible, which means the processing of the entire filter window at one pixel clock cycle. This feature of the kernel-based design is supported by the arrangement of the input data into groups so that the internal clock of the design is a multiple of the pixel clock given by a targeted system. Additionally, by the exploitation of the separability and the symmetry of one filter component, the complexity of the design is widely reduced. Combining these features, the bilateral filter is implemented as a highly parallelized pipeline structure with very economical and effective utilization of dedicated resources. Due to the modularity of the filter design, kernels of different sizes can be implemented with low effort using our design and given instructions for scaling. As the original form of the bilateral filter with no approximations or modifications is implemented, the resulting image quality depends on the chosen filter parameters only. Due to the quantization of the filter coefficients, only negligible quality loss is introduced.
    IEEE Transactions on Industrial Electronics 08/2014; 61(8):4093-4104. DOI:10.1109/TIE.2013.2284133 · 6.50 Impact Factor
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    ABSTRACT: The Six-port concept has been investigated in the last decades for numerous applications. Besides the use in network analyzers, communication transceivers and direction-of-arrival detectors the Six-port has also been applied in radar systems. Due to its excellent phase discrimination capability, Six-port radar features high range resolution and is therefore predestined for precise displacement and vibration measurements. In this paper, the influence of the antenna on both, accuracy and precision, of monostatic as well as bistatic Six-port radar systems will be studied.
    Proc. IEEE APS Topical Conf. Antennas Propag. Wireless Commun., Aruba; 08/2014

Publication Stats

3k Citations
207.57 Total Impact Points


  • 2004–2015
    • Universitätsklinikum Erlangen
      Erlangen, Bavaria, Germany
  • 2003–2014
    • Friedrich-Alexander Universität Erlangen-Nürnberg
      • Lehrstuhl für Technische Elektronik
      Erlangen, Bavaria, Germany
  • 2006–2011
    • Nuremberg University of Music
      Nuremberg, Bavaria, Germany
    • IST Austria
      Klosterneuberg, Lower Austria, Austria
  • 2010
    • Universität Bremen
      Bremen, Bremen, Germany
    • Universität Stuttgart
      Stuttgart, Baden-Württemberg, Germany
  • 2009
    • Technische Universität Dresden
      Dresden, Saxony, Germany
  • 2000–2008
    • Infineon Technologies
      München, Bavaria, Germany
  • 2003–2007
    • Linz Center of Mechatronics GmbH
      Linz, Upper Austria, Austria
  • 1997–2005
    • Johannes Kepler University Linz
      • Institut für Nachrichtentechnik und Hochfrequenzsysteme
      Linz, Upper Austria, Austria
  • 2002
    • Electronic Components, Modules and Systems (EPCOS)
      München, Bavaria, Germany
  • 2000–2001
    • Technische Universität Clausthal
      • Department of Electrical Information Technology
      Bergstadt-Clausthal-Zellerfeld, Lower Saxony, Germany
    • Chiba University
      • • Faculty of Engineering
      • • Department of Electrical and Electronic Engineering
      Chiba-shi, Chiba-ken, Japan
  • 1997–1998
    • Vienna University of Technology
      • Institute of Sensor and Actuator Systems
      Wien, Vienna, Austria
  • 1988–1998
    • Siemens
      München, Bavaria, Germany
  • 1989–1996
    • Technische Universität München
      • Lehrstuhl für Hochfrequenztechnik HFT
      München, Bavaria, Germany