@misc{KauleLuoChevtchenkoetal., author = {Kaule, Evelyne and Luo, Peng and Chevtchenko, Serguei A. and Andrei, Cristina and Rudolph, Matthias}, title = {Analysis for the optimization of a rugged GaN low-noise amplifier MMIC with a compact stacked first amplifier stage}, series = {2024 IEEE International Conference on Microwaves, Communications, Antennas, Biomedical Engineering and Electronic Systems (COMCAS)}, journal = {2024 IEEE International Conference on Microwaves, Communications, Antennas, Biomedical Engineering and Electronic Systems (COMCAS)}, publisher = {IEEE}, doi = {10.1109/COMCAS58210.2024.10666226}, pages = {1 -- 4}, language = {en} } @misc{HaqueBeleniotisYazdanietal., author = {Haque, Sanaul and Beleniotis, Petros and Yazdani, Hossein and Rudolph, Matthias}, title = {Ka-Band GaN power amplifier with integrated DC supply switch and RF switch}, series = {2024 25th International Microwave and Radar Conference (MIKON)}, journal = {2024 25th International Microwave and Radar Conference (MIKON)}, publisher = {IEEE}, doi = {10.23919/MIKON60251.2024.10633971}, pages = {1 -- 5}, language = {en} } @incollection{NaumannRudolph, author = {Naumann, Matthias and Rudolph, David}, title = {L{\"a}ndliche Utopien als infrastrukturelle Utopien : Progressive Alternativen zu infrastruktureller Peripherisierung und infrastrukturellem Populismus.}, series = {L{\"a}ndliche Utopien : Herausforderungen und Alternativen regionaler Entwicklungen.}, booktitle = {L{\"a}ndliche Utopien : Herausforderungen und Alternativen regionaler Entwicklungen.}, publisher = {Transcript Verlag}, address = {Bielefeld}, isbn = {978-3-8394-7233-0}, doi = {10.1515/9783839472330}, pages = {115 -- 126}, language = {de} } @misc{KauleYazdaniRudolph, author = {Kaule, Evelyne and Yazdani, Hossein and Rudolph, Matthias}, title = {Highly Linear Concurrent Tri-Band GaN LNA MMIC for 0.8/1.8/3.6 GHz Applications}, series = {24th International Microwave and Radar Conference (MIKON)}, journal = {24th International Microwave and Radar Conference (MIKON)}, isbn = {978-83-956020-3-0}, doi = {10.23919/Mikon54314.2022.9924770}, pages = {3}, language = {en} } @misc{ManchandaOkochaRudolph, author = {Manchanda, Prabhav and Okocha, Jonathan and Rudolph, Matthias}, title = {Improved Sensitivity of Zero Bias Diode Power Detectors using Impedance Tuners}, series = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON)}, journal = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON)}, isbn = {978-1-6654-5203-8}, doi = {10.1109/MAPCON56011.2022.10047233}, pages = {1261 -- 1266}, language = {en} } @misc{RaoDoernerYazdanietal., author = {Rao, Megha Krishnaji and D{\"o}rner, Ralf and Yazdani, Hossein and Rudolph, Matthias}, title = {GaN-HEMT Based Common-Gate LNA MMIC with Integrated Switch for Compact 5G Transceivers}, series = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON)}, journal = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON)}, isbn = {978-1-6654-5203-8}, doi = {10.1109/MAPCON56011.2022.10047410}, pages = {1104 -- 1107}, language = {en} } @misc{SriperumbuduriWenzelRudolph, author = {Sriperumbuduri, Venkata Pawan and Wenzel, Andreas and Rudolph, Matthias}, title = {Mathematical Analysis of Switching HBT Devices}, series = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON), 12-16 December 2022, Bangalore, India}, journal = {IEEE Microwaves, Antennas, and Propagation Conference (MAPCON), 12-16 December 2022, Bangalore, India}, isbn = {978-1-6654-5203-8}, doi = {10.1109/MAPCON56011.2022.10047449}, pages = {827 -- 831}, language = {en} } @misc{BeleniotisSchniederChevtchenkoetal., author = {Beleniotis, Petros and Schnieder, Frank and Chevtchenko, Serguei A. and Rudolph, Matthias}, title = {Localization of Trapping Effects in GaN HEMTs with Pulsed S-parameters and Compact Models}, series = {17th European Microwave Integrated Circuits Conference (EuMIC)}, journal = {17th European Microwave Integrated Circuits Conference (EuMIC)}, isbn = {978-2-87487-070-5}, doi = {10.23919/EuMIC54520.2022.9923511}, pages = {149 -- 152}, language = {de} } @misc{HuynhLeLehmannetal., author = {Huynh, Dang Khoa and Le, Quang Huy and Lehmann, Steffen and Zhao, Zhixing and Bossu, Germain and Arfaoui, Wafa and K{\"a}mpfe, Thomas and Rudolph, Matthias}, title = {Impact of Off-State Stress on SiGe-channel p-FETs in 22nm FDSOI under Large-Signal Operation}, series = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, isbn = {978-2-87487-073-6}, doi = {10.23919/EuMIC58042.2023.10288886}, pages = {173 -- 176}, language = {en} } @misc{ZervosBeleniotisKrauseetal., author = {Zervos, Christos and Beleniotis, Petros and Krause, Sascha and Ritter, Dan and Rudolph, Matthias}, title = {The role of gate leakage on surface-related current collapse in AlGaN/GaN HEMTs}, series = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, volume = {2023}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, isbn = {978-2-87487-073-6}, doi = {10.23919/EuMIC58042.2023.10289036}, pages = {297 -- 300}, language = {en} } @misc{SriperumbuduriYacoubWentzeletal., author = {Sriperumbuduri, Venkata Pawan and Yacoub, Hady and Wentzel, Andreas and Johansen, Tom K. and Rudolph, Matthias}, title = {Design and Analysis of a 50GHz InP DHBT Class-E Power Amplifer Providing 2.3}, series = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, doi = {10.23919/EuMIC58042.2023.10288688}, pages = {4}, language = {en} } @misc{HaqueAndreiYazdanietal., author = {Haque, Sanaul and Andrei, Cristina and Yazdani, Hossein and Rudolph, Matthias}, title = {On the Survivability of a 28 - 32 GHz GaN Low Noise Amplifier}, series = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC), 18-19 September 2023, Berlin}, isbn = {978-2-87487-073-6}, doi = {10.23919/EuMIC58042.2023.10288728}, pages = {4}, language = {de} } @misc{KauleLuoChevtchenkoetal., author = {Kaule, Evelyne and Luo, Peng and Chevtchenko, Serguei A. and Rudolph, Matthias and Andrei, Cristina}, title = {Compact Stacked Rugged GaN Low-Noise Amplifier MMIC under Input Power Overdrive Condition}, series = {18th European Microwave Integrated Circuits Conference (EuMIC),18-19 September 2023, Berlin}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC),18-19 September 2023, Berlin}, isbn = {978-2-87487-073-6}, doi = {10.23919/EuMIC58042.2023.10288650}, pages = {9 -- 12}, language = {en} } @misc{BeleniotisZervosSchniederetal., author = {Beleniotis, Petros and Zervos, Christos and Schnieder, Frank and Rudolph, Matthias}, title = {Dynamic RD Modeling by Exploiting Gate Current Dependency of Virtual Gate Effect}, series = {18th European Microwave Integrated Circuits Conference (EuMIC),18-19 September 2023, Berlin}, journal = {18th European Microwave Integrated Circuits Conference (EuMIC),18-19 September 2023, Berlin}, isbn = {978-2-87487-073-6}, doi = {10.23919/EuMIC58042.2023.10288955}, pages = {1 -- 4}, language = {en} } @misc{RaoDoernerChevtchenkoetal., author = {Rao, Megha Krishnaji and D{\"o}rner, Ralf and Chevtchenko, Serguei A. and Haque, Sanaul and Rudolph, Matthias}, title = {Common-Gate LNA MMIC With Switching Feature Using GaN-HEMT for 5G RF Front-Ende}, series = {IEEE Microwave and Wireless Technology Letters}, volume = {33}, journal = {IEEE Microwave and Wireless Technology Letters}, number = {10}, issn = {2771-9588}, doi = {10.1109/LMWT.2023.3306177}, pages = {1446 -- 1449}, language = {en} } @misc{LeHuynhLehmannetal., author = {Le, Quang Huy and Huynh, Dang Khoa and Lehmann, Steffen and Zhao, Zhixing and Schwan, Christoph T. and K{\"a}mpfe, Thomas and Rudolph, Matthias}, title = {22-nm FDSOI CMOS Noise Modeling and Anlaysis in mm-Wave Frequency Range}, series = {23rd Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 22 February 2023, Las Vegas, NV, USA}, journal = {23rd Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, 22 February 2023, Las Vegas, NV, USA}, isbn = {978-1-6654-9319-2}, issn = {2474-9761}, doi = {10.1109/SiRF56960.2023.10046210}, pages = {31 -- 33}, language = {en} } @incollection{Rudolph, author = {Rudolph, Matthias}, title = {Wave Propagation on Transmission Lines and Cables}, series = {Fundamentals of RF and Microwave Techniques and Technologies}, booktitle = {Fundamentals of RF and Microwave Techniques and Technologies}, editor = {Hartnagel, Hans L. and Quay, R{\"u}diger and Rohde, Ulrich L. and Rudolph, Matthias}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-94098-0}, doi = {10.1007/978-3-030-94100-0_2}, pages = {55 -- 142}, language = {en} } @incollection{Rudolph, author = {Rudolph, Matthias}, title = {Properties of Coaxial Cables and Transmission Lines, Directional Couplers and RF Filters}, series = {Fundamentals of RF and Microwave Techniques and Technologies}, booktitle = {Fundamentals of RF and Microwave Techniques and Technologies}, editor = {Hartnagel, Hans L. and Quay, R{\"u}diger and Rohde, Ulrich L. and Rudolph, Matthias}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-94098-0}, doi = {10.1007/978-3-030-94100-0_4}, pages = {197 -- 333}, language = {en} } @incollection{Rudolph, author = {Rudolph, Matthias}, title = {Interference and Noise}, series = {Fundamentals of RF and Microwave Techniques and Technologies}, booktitle = {Fundamentals of RF and Microwave Techniques and Technologies}, editor = {Hartnagel, Hans L. and Quay, R{\"u}diger and Rohde, Ulrich L. and Rudolph, Matthias}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-94098-0}, doi = {10.1007/978-3-030-94100-0_8}, pages = {747 -- 791}, language = {en} } @misc{YazdaniBeleniotisBrunneretal., author = {Yazdani, Hossein and Beleniotis, Petros and Brunner, Frank and Ostermay, Ina and W{\"u}rfl, Joachim and Rudolph, Matthias and Heinrich, Wolfgang and Hilt, Oliver}, title = {K/Ka-Band-GaN-High-Electron-Mobility Transistors Technology with 700 mS mm-1 Extrinsic Transconductance}, series = {Physica Status Solidi}, journal = {Physica Status Solidi}, doi = {10.1002/pssa.202400592}, pages = {8}, language = {en} } @misc{KaredSilaghiRudolphetal., author = {Kared, Trusha and Silaghi, Helga and Rudolph, Matthias and Silaghi, Andrei and Rohde, Ulrich L.}, title = {Design of a fixed IF down-conversion double-balanced mixer for UHF band applications}, series = {Sensors}, volume = {25}, journal = {Sensors}, number = {3}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s25030608}, pages = {1 -- 29}, abstract = {This paper presents a new SiGe HBT-based high dynamic range double-balanced down-conversion differential mixer. Operating within the 0.5 GHz to 1.8 GHz range, the suggested mixer is appropriate for a variety of applications, such as cellular base stations, satellite communication (SATCOM), and military radar. The down-conversion mixer is made up of a single-ended to a differential-balanced radiofrequency (RF) stage, a dual feedback linearization for the RF stage, a local oscillator (LO) balun, LO mixing cores, and a fixed intermediate frequency (IF)-tuned circuit connected between two outputs to serve as a load at 145 MHz. Compared to earlier research in the literature, the measured SSB noise figure is approximately 7 dB ± 0.4 dB, and the measured conversion gain is approximately 12 dB ± 1 dB for a full band of operation. The mixer achieves a good return loss of over 8 dB for an RF and LO port in the desired band and a measured return loss of over 18 dB at 145 MHz and IF frequency. Furthermore, the design achieved an RF-to-IF isolation of greater than 35 dB, LO feedthrough, and an LO leakage isolation of better than 50 dB. Lastly, the measured third-order intercept point was found to be +4.7 dBm, and the 1 dB compression point was approximately -8 dBm. These results demonstrate good linearity performance.}, language = {en} } @misc{HaqueDoernerChevtchenkoetal., author = {Haque, Sanaul and Doerner, Ralf and Chevtchenko, Serguei and Rudolph, Matthias}, title = {Linearity enhancement of GaN LNA MMIC using RF-based approach of derivative superposition}, series = {2025 20th European Microwave Integrated Circuits Conference (EuMIC)}, journal = {2025 20th European Microwave Integrated Circuits Conference (EuMIC)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-2-87487-082-8}, doi = {10.23919/EuMIC65284.2025.11234643}, pages = {25 -- 28}, abstract = {This work presents a new methodology of implementing the derivative superposition (DS) technique based on third-order intermodulation current cancellation using harmonic-balance simulation. This approach is especially suitable for high-frequency applications due to the loading effect in transistors connected in parallel. To the best of the authors' knowledge, this work demonstrates for the first time the implementation of the DS technique in GaN-based LNA MMIC. As a proof of concept, two single-stage 4.5-5.5 GHz LNA MMICs, with and without DS technique, are designed using FBH 250 nm GaN on SiC process, with a focus on improving linearity without additional power consumption. A two-tone measurement around 5 GHz shows a 6 dB output third-order intercept point (OIP3) improvement, from 38.7 dBm for a conventional LNA to 44.9 dBm for an LNA with DS. This leads to an improvement in the linearity figure of merit (LFOM = OIP3/Pdc) from 6.6 to 28.}, language = {en} } @misc{BeleniotisAndreiZervosetal., author = {Beleniotis, Petros and Andrei, Cristina and Zervos, Christos and Rohde, Ulrich L. and Rudolph, Matthias}, title = {GaN trap model extraction based on MHz load-line measurements}, series = {2025 IEEE/MTT-S International Microwave Symposium - IMS 2025}, journal = {2025 IEEE/MTT-S International Microwave Symposium - IMS 2025}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3315-1409-9}, doi = {10.1109/IMS40360.2025.11104000}, pages = {1059 -- 1062}, abstract = {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.}, language = {en} } @misc{BeleniotisAndreiRohdeetal., author = {Beleniotis, Petros and Andrei, Cristina and Rohde, Ulrich L. and Rudolph, Matthias}, title = {Determining GaN HEMT trap models from MHz load-line measurement — synthesis and evaluation}, series = {2025 16th German Microwave Conference (GeMiC)}, journal = {2025 16th German Microwave Conference (GeMiC)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-3-9820397-4-9}, doi = {10.23919/GeMiC64734.2025.10978988}, pages = {451 -- 454}, abstract = {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.}, language = {en} } @misc{ManchandaKnaackTostetal., author = {Manchanda, Prabhav and Knaack, Marcus and Tost, Frank and Andrei, Cristina and Rudolph, Matthias}, title = {Digitally reconfigurable power detector}, series = {2025 16th German Microwave Conference (GeMiC)}, journal = {2025 16th German Microwave Conference (GeMiC)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-3-9820397-4-9}, doi = {10.23919/GeMiC64734.2025.10979055}, pages = {439 -- 442}, abstract = {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.}, language = {en} } @misc{ManchandaKnaackLiaoetal., author = {Manchanda, Prabhav and Knaack, Marcus and Liao, Juhua and Andrei, Cristina and Rudolph, Matthias}, title = {Detection of vital signs using noncoherent receivers}, series = {2025 22nd European Radar Conference (EuRAD)}, journal = {2025 22nd European Radar Conference (EuRAD)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-2-87487-083-5}, doi = {10.23919/EuRAD65285.2025.11233845}, pages = {363 -- 366}, abstract = {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.}, language = {en} } @misc{KrishnajiRaoWentzelHoffmannetal., author = {Krishnaji Rao, Megha and Wentzel, Andreas and Hoffmann, Thomas and Schellhase, Lars and A. Chevtchenko, Serguei and Yazdani, Hossein and Rudolph, Matthias}, title = {Digital GaN-based transceiver architectures for sustainable 5G networks}, series = {International journal of microwave and wireless technologies}, journal = {International journal of microwave and wireless technologies}, publisher = {Cambridge University Press (CUP)}, address = {Cambridge}, issn = {1759-0787}, doi = {10.1017/S1759078725102262}, pages = {1 -- 9}, abstract = {This paper presents two distinct configurations of a GaN-based digital transceiver (TRx) to evaluate their performance and integration efficiency. The first configuration, features a novel low-noise amplifier with integrated switching capability (LNAiS) and a digital class-E power amplifier (PA) on a single compact chip. The LNAiS eliminates the need for an external antenna switch, reducing module complexity and chip size while maintaining high performance. It achieves a gain of 12.7 dB and a noise figure of 3 dB at 4.7 GHz in Rx mode and provides over 20 dB isolation in Tx mode across 4.7-7.4 GHz. The digital PA demonstrates flexibility and efficiency, achieving 46\% and 23\% efficiencies for 20 MHz LTE and OFDM signals, respectively, and 22\% for a 240 MHz OFDM signal with 10 dB PAPR. The second configuration integrates the same concept of digital PA with a standard LNA and an SPDT switch (LNAsS), achieving a gain of 24.8 dB and a noise figure of 2.65 dB at 4.2 GHz. This work highlights the trade-offs between these two architectures and demonstrates that the LNAiS-based approach drives the development of greener, more flexible, compact,lower-complexity, and cost-effective transceivers for 5G networks.}, language = {en} } @misc{BeleniotisZervosKrauseetal., author = {Beleniotis, Petros and Zervos, Christos and Krause, Sascha and Yazdani, Hossein and Rudolph, Matthias}, title = {Traps in GaN HEMTs : from characterization to model development and device optimization}, series = {2025 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS)}, journal = {2025 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {979-8-3315-9172-4}, doi = {10.1109/BCICTS63111.2025.11211504}, pages = {1 -- 8}, abstract = {This paper reviews a comprehensive strategy designed to address the impact of traps across the entire field of GaN HEMT operation. It begins with the characterization of trap levels and the measurement of trap time constants. The study then progresses to TCAD simulations to examine the location of the observed trap levels and their effect on device performance. Finally, it introduces the development of a compact trap model grounded in Shockley-Read-Hall statistics. The proposed model is capable of accurately predicting trapping effects across all combinations of voltage, temperature, and time. The paper concludes by highlighting the synergy TCAD-compact-model, underscoring its utility in device optimization schemes.}, language = {en} } @misc{RaoBeleniotisHoffmannetal., author = {Rao, Megha Krishnaji and Beleniotis, Petros and Hoffmann, Thomas and Yazdani, Hossein and Wentzel, Andreas and Rudolph, Matthias}, title = {Switch-integrated GaN LNAs : a technology-focused analysis}, series = {2025 20th European Microwave Integrated Circuits Conference (EuMIC)}, journal = {2025 20th European Microwave Integrated Circuits Conference (EuMIC)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-2-87487-082-8}, doi = {10.23919/EuMIC65284.2025.11234676}, pages = {29 -- 32}, abstract = {This paper presents the first circuit-level analysis of a two-stage GaN-HEMT LNA with an integrated switch, comparing two distinct technologies: one with a standard passivation layer (Type A) and another featuring an advanced passivation layer (Type B). Through a detailed evaluation of their performance in both amplification and isolation modes, the study highlights Type B as a significant advancement over Type A. Leveraging technological enhancements, including an improved passivation layer and slightly optimized component matching, Type B demonstrates superior performance. The results are compelling, with Type B achieving a gain of 19 dB, a low noise figure of 1.17dB, and small-signal isolation exceeding 30 dBm at 5.2 GHz. These achievements establish Type B as a formidable option for future 5G telecommunication systems, offering a performance that challenges traditional designs that use separate switches.}, language = {en} } @misc{OkochaAndreiRudolph, author = {Okocha, Jonathan and Andrei, Cristina and Rudolph, Matthias}, title = {On the repeatability of low cost varactor—based RF impedance tuners}, series = {2025 55th European Microwave Conference (EuMC)}, journal = {2025 55th European Microwave Conference (EuMC)}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-2-87487-081-1}, doi = {10.23919/EuMC65286.2025.11234977}, pages = {683 -- 686}, abstract = {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.}, language = {en} } @incollection{GailingNaumannRudolph, author = {Gailing, Ludger and Naumann, Matthias and Rudolph, David}, title = {Local and regional conflicts in the energy transition}, series = {Reference module in materials science and materials engineering}, booktitle = {Reference module in materials science and materials engineering}, publisher = {Elsevier BV}, address = {Amsterdam}, isbn = {978-0-12-803581-8}, doi = {10.1016/B978-0-443-29210-1.00073-X}, pages = {1 -- 9}, abstract = {Energy transitions are accompanied by a range of conflicts, which mostly occur at local and regional scales. To help understand these, this chapter provides a typology of energy conflicts, of which the most common are distribution and procedural conflicts. Energy conflicts entail material, spatial, temporal and actor dimensions. For both major types of energy conflict and their different dimensions, the chapter provides empirical examples from Denmark and the United Kingdom. Energy conflicts are a challenge for energy transitions, but they are also drivers of social change, which are inherent in the pluralistic structure of modern societies.}, language = {en} }