TY - CHAP A1 - Rudolph, Matthias A1 - Andrei, Cristina A1 - Liero, Armin A1 - Lossy, Richard A1 - Heinrich, Wolfgang T1 - Highly Linear Broadband GaN-based Low-noise Amplifier Y1 - 2010 ER - TY - CHAP A1 - Andrei, Cristina A1 - Dörner, Ralf A1 - Bengtsson, Olof A1 - Chevtchenko, Serguei A. A1 - Heinrich, Wolfgang A1 - Rudolph, Matthias T1 - Highly Linear X-Band GaN-Based Low-Noise Amplifier T2 - Signals, Systems, and Electronics (ISSSE), 2012 International Symposium on , Potsdam Y1 - 2012 UR - http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6362332 SN - 978-1-4673-4454-8 SN - 978-1-4673-4453-1 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Andrei, Cristina A1 - Bengtsson, Olof A1 - Dörner, Ralf A1 - Chevtchenko, Serguei A. A1 - Heinrich, Wolfgang A1 - Rudolph, Matthias T1 - Dynamic behaviour of a Low-Noise Amplifier GaN MMIC under input power overdrive T2 - Proceedings of 45th European Microwave Conference, Paris 2015 Y1 - 2015 U6 - https://doi.org/10.1109/EuMC.2015.7345742 SP - 231 EP - 234 PB - IEEE ER - TY - CHAP A1 - Andrei, Cristina A1 - Bengtsson, Olof A1 - Dörner, Ralf A1 - Chevtchenko, Serguei A. A1 - Rudolph, Matthias T1 - Robust Stacked GaN-Based Low-Noise Amplifier MMIC for Receiver Applications T2 - IEEE MTT-S International Microwave Symposium (IMS), 17-22 May 2015 Y1 - 2015 U6 - https://doi.org/10.1109/MWSYM.2015.7166766 PB - IEEE ER - TY - CHAP A1 - Rudolph, Matthias A1 - Andrei, Cristina A1 - Dörner, Ralf A1 - Chevtchenko, Serguei A. A1 - Heinrich, Wolfgang T1 - Noise in GaN HEMTs and Circuits T2 - 24th International Conference on Noise and Fluctuations (ICNF), Vilnius, Lithuania, June 20-23, 2017 Y1 - 2017 SN - 978-1-5090-2760-6 U6 - https://doi.org/10.1109/ICNF.2017.7985978 SP - 1 EP - 4 PB - IEEE CY - Piscataway, NJ ER - TY - CHAP A1 - Andrei, Cristina A1 - Dörner, Ralf A1 - Chevtchenko, Serguei A. A1 - Heinrich, Wolfgang A1 - Rudolph, Matthias T1 - On the Optimization of GaN HEMT Layout for Highly Rugged Low-Noise Amplifier Design T2 - 12th European Microwave Integrated Circuits Conference (EuMIC), 8-10 Oct. 2017, Nuremberg, Germany Y1 - 2017 SN - 978-2-87487-048-4 U6 - https://doi.org/10.23919/EuMIC.2017.8230705 SP - 244 EP - 247 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Kaule, Evelyne A1 - Andrei, Cristina A1 - Gerlich, Stefan A1 - Dörner, Ralf A1 - Rudolph, Matthias T1 - Limiting the Output Power of Rugged GaN LNAs T2 - 14th European Microwave Integrated Circuits Conference (EuMIC) N2 - Rugged GaN HEMT low-noise amplifiers are well established, but the common concept of achieving ruggedness by applying the gate supply voltage through a high ohmic resistance might not be sufficient in addition to control the maximum output power. This paper shifts the focus to the protection of subsequent stages and proposes a circuit concept based on an output attenuator and an adaptive drain supply. It is shown that the concept implementation provides an attenuation of up to 28dB under input overdrive condition while leaving small-signal noise Figure unaffected. KW - Power generation; Logic Gates; Gallium nitride; Attenuators; HEMTs; Printed circuits; Power measurement; Limit; GaN; HEMT; ruggedness; low noise amplifier (LNA); receiver Y1 - 2019 SN - 978-2-87487-056-9 SN - 978-1-7281-0768-4 U6 - https://doi.org/10.23919/EuMIC.2019.8909653 SP - 240 EP - 242 CY - Paris, France ER - TY - GEN A1 - Kaule, Evelyne A1 - Andrei, Cristina A1 - Gerlich, Stefan A1 - Dörner, Ralf A1 - Rudolph, Matthias T1 - Limiting the Output Power of Rugged GaN LNAs T2 - Proceedings of 49th European Microwave Conference (EuMC) N2 - Rugged GaN HEMT low-noise amplifiers are well established, but the common concept of achieving ruggedness by applying the gate supply voltage through a high ohmic resistance might not be sufficient in addition to control the maximum output power. This paper shifts the focus to the protection of subsequent stages and proposes a circuit concept based on an output attenuator and an adaptive drain supply. It is shown that the concept implementation provides an attenuation of up to 28 dB under input overdrive condition while leaving small-signal noise figure unaffected. KW - Power generation; Logic Gates; Gallium nitride; Attenuators; HEMTs; Printed circuits; Power measurement; Limit; GaN; HEMT; ruggedness; low noise amplifier (LNA); receiver Y1 - 2019 SN - 978-2-87487-055-2 SN - 978-1-7281-1798-0 U6 - https://doi.org/10.23919/EuMC.2019.8910675 SP - 794 EP - 796 CY - Paris, France ER - TY - GEN A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - Properties of GaN LNAs for Front-End Applications T2 - WFC Towards A One-Chip Solution for GaN Front-Ends, Microwave Symposiums, Boston, 2019 Y1 - 2019 UR - https://www.b-tu.de/en/endowed-chair-rf-and-microwave-techniques/publications/publications#c208430 ER - TY - GEN A1 - Kaule, Evelyne A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - Output Power Limited Rugged GaN LNA MMIC T2 - 16th European Microwave Integrated Circuits Conference (EuMIC), 03-04 April 2022, London, United Kingdom Y1 - 2022 SN - 978-2-87487-064-4 SN - 978-1-6654-4722-5 U6 - https://doi.org/10.23919/EUMIC50153.2022.9784020 SP - 133 EP - 135 ER - TY - GEN A1 - Manchanda, Prabhav A1 - Andrei, Cristina A1 - Tost, Frank A1 - Rudolph, Matthias T1 - A pHEMT based power detector for radar applications T2 - 2024 54th European Microwave Conference (EuMC) Y1 - 2024 U6 - https://doi.org/10.23919/EuMC61614.2024.10732043 SP - 992 EP - 995 PB - IEEE ER - TY - GEN A1 - Haque, Sanaul A1 - Andrei, Cristina A1 - Wolf, Mihaela A1 - Hilt, Oliver A1 - Rudolph, Matthias T1 - Switch integrated Ka-Band low noise amplifier in GaN/AlN HEMT technology T2 - 2024 19th European Microwave Integrated Circuits Conference (EuMIC) Y1 - 2024 U6 - https://doi.org/10.23919/EuMIC61603.2024.10732731 SP - 351 EP - 354 PB - IEEE ER - TY - GEN A1 - Rudolph, Matthias A1 - Beleniotis, Petros A1 - Zervos, Christos A1 - Rohde, Ulrich L. A1 - Andrei, Cristina T1 - Determining GaN HEMT trap models from MHz load-line measurement : a case study T2 - 2024 15th German Microwave Conference (GeMiC) Y1 - 2024 U6 - https://doi.org/10.23919/GeMiC59120.2024.10485297 SP - 29 EP - 32 PB - IEEE ER - TY - GEN A1 - Kaule, Evelyne A1 - Luo, Peng A1 - Chevtchenko, Serguei A. A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - Analysis for the optimization of a rugged GaN low-noise amplifier MMIC with a compact stacked first amplifier stage T2 - 2024 IEEE International Conference on Microwaves, Communications, Antennas, Biomedical Engineering and Electronic Systems (COMCAS) Y1 - 2024 U6 - https://doi.org/10.1109/COMCAS58210.2024.10666226 SP - 1 EP - 4 PB - IEEE ER - TY - GEN A1 - Haque, Sanaul A1 - Andrei, Cristina A1 - Yazdani, Hossein A1 - Rudolph, Matthias T1 - On the Survivability of a 28 - 32 GHz GaN Low Noise Amplifier T2 - 18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin Y1 - 2023 SN - 978-2-87487-073-6 SN - 979-8-3503-4833-0 U6 - https://doi.org/10.23919/EuMIC58042.2023.10288728 ER - TY - GEN A1 - Kaule, Evelyne A1 - Luo, Peng A1 - Chevtchenko, Serguei A. A1 - Rudolph, Matthias A1 - Andrei, Cristina T1 - Compact Stacked Rugged GaN Low-Noise Amplifier MMIC under Input Power Overdrive Condition T2 - 18th European Microwave Integrated Circuits Conference (EuMIC),18-19 September 2023, Berlin Y1 - 2023 SN - 978-2-87487-073-6 SN - 979-8-3503-4833-0 U6 - https://doi.org/10.23919/EuMIC58042.2023.10288650 SP - 9 EP - 12 ER - TY - GEN A1 - Beleniotis, Petros A1 - Andrei, Cristina A1 - Zervos, Christos A1 - Rohde, Ulrich L. A1 - Rudolph, Matthias T1 - GaN trap model extraction based on MHz load-line measurements T2 - 2025 IEEE/MTT-S International Microwave Symposium - IMS 2025 N2 - The extraction of model parameters for GaN HEMTs is a challenging task that typically requires a comprehensive series of pulsed measurements to ensure that the resulting model is both accurate and convergence-stable. This study introduces, for the first time, an extraction procedure that utilizes I-V curves generated by MHz load-line measurements, effectively replacing the complex and time-intensive pulsed measurements. A drain-lag model extraction was based on load-line I-V curves and validated along with a pulsed-IV-based model through RF large-signal simulations, demonstrating excellent performance. KW - GaN KW - Compact model KW - Load-line KW - Model parameter extraction Y1 - 2025 SN - 979-8-3315-1409-9 U6 - https://doi.org/10.1109/IMS40360.2025.11104000 SP - 1059 EP - 1062 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Beleniotis, Petros A1 - Andrei, Cristina A1 - Rohde, Ulrich L. A1 - Rudolph, Matthias T1 - Determining GaN HEMT trap models from MHz load-line measurement — synthesis and evaluation T2 - 2025 16th German Microwave Conference (GeMiC) N2 - The modeling of GaN HEMTs is closely associated with pulsed measurements, which are essential for extracting model parameters related to trapping and thermal effects. However, these characterizations are often hindered by high costs and the time-intensive nature of the measurement process. In this paper, we present and evaluate a novel approach for trap model extraction that utilizes MHz load-line measurements. Our analysis includes a comparative study of the measurements and a demonstration of modeling based on the proposed methodology. KW - Compact modeling KW - Load-line KW - Model parameter extraction KW - GaN HEMT KW - ASM-HEMT Y1 - 2025 SN - 978-3-9820397-4-9 U6 - https://doi.org/10.23919/GeMiC64734.2025.10978988 SP - 451 EP - 454 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Manchanda, Prabhav A1 - Knaack, Marcus A1 - Tost, Frank A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - Digitally reconfigurable power detector T2 - 2025 16th German Microwave Conference (GeMiC) N2 - This paper presents a reconfigurable diode detector operating at 24 GHz, capable of dynamically adjusting its output voltage and linear range through digital control of the load impedance. The variation in load impedance is initially achieved by employing a variable resistor within the baseband amplifier. Subsequently, the same effect is accomplished using a fully digital solution by configuring the internal programmable gain amplifier (PGA) of an analog-to-digital converter (ADC). The detector, the baseband amplifier, and the ADC are fabricated using commercially available components. Experimental results demonstrate that the linear range can be extended significantly by reducing the input impedance of the baseband amplifier, whereas an increase in impedance results in an elevated output voltage. Similar trends are observed when utilizing the PGA within the ADC. The results demonstrate a reconfigurable diode detector that employs digital control to dynamically optimize performance metrics, including output voltage and linear range. This adaptability renders it highly versatile and well-suited for a broad spectrum of modern RF system applications. KW - Diode detector KW - Radar KW - Reconfigurable power detector KW - Square-law detector Y1 - 2025 SN - 978-3-9820397-4-9 U6 - https://doi.org/10.23919/GeMiC64734.2025.10979055 SP - 439 EP - 442 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Manchanda, Prabhav A1 - Knaack, Marcus A1 - Liao, Juhua A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - Detection of vital signs using noncoherent receivers T2 - 2025 22nd European Radar Conference (EuRAD) N2 - This work introduces a novel concept for detecting displacements, specifically vital signs resulting from physiological activity, using noncoherent receivers. A theoretical analysis of phase noise propagation in the receiver architecture reveals that individual uncorrelated phase noise contributions add at the intermediate frequency, thereby defining the detection sensitivity. System validation using a reflector mounted on a modulator producing controlled oscillations demonstrates the ability to detect sub-millimeter displacements, provided the residual phase noise from the uncorrelated oscillators remains low. Extending this concept, the system accurately detects respiration and cardiac activity, with results is comparable to those of a reference ECG sensor. These findings open new possibilities for multistatic vital sign detection systems, offering reliable, non-contact sensing for healthcare and remote monitoring applications. KW - Uncorrelated phase noise KW - Noncoherent radar KW - Vital signs KW - Multistatic radar Y1 - 2025 SN - 978-2-87487-083-5 U6 - https://doi.org/10.23919/EuRAD65285.2025.11233845 SP - 363 EP - 366 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Okocha, Jonathan A1 - Andrei, Cristina A1 - Rudolph, Matthias T1 - On the repeatability of low cost varactor—based RF impedance tuners T2 - 2025 55th European Microwave Conference (EuMC) N2 - This paper introduces a concise methodology for assessing the repeatability of low-cost, varactor-based RF impedance tuners by employing a dB-based metric that quantifies how accurately each tuner reproduces a target impedance over repeated cycles. Both blocked and cyclical measurement strategies are used to highlight large impedance transitions near high-reflection states that exacerbate non-idealities. In addition, the method rigorously characterizes issues such as systematic offsets, drift, and hysteresis, common challenges that can impair tuner performance, allowing targeted improvements. Demonstrations with a BST varactor prototype underscore the importance of identifying and quantifying these effects to ensure consistent tuner performance in real-world RF testing environments. KW - RF impedance tuning KW - Tuner repeatability KW - Mechanical tuner KW - Electronic tuners KW - Load-pull KW - Measurement methodology KW - Smith chart tuners KW - dB-based metric KW - Tuner accuracy Y1 - 2025 SN - 978-2-87487-081-1 U6 - https://doi.org/10.23919/EuMC65286.2025.11234977 SP - 683 EP - 686 PB - IEEE CY - Piscataway, NJ ER -