Antenna-VSWR-Resilient Load-Modulation Power Amplifiers for 5G-and-Beyond Communications

Dr. Kenle Chen
Assistant Professor
University of Central Florida

Abstract: Load modulation has been a compelling technology for high-efficiency power amplification of spectrally efficient modulated signals. However, conventional Doherty power amplifiers (PAs) face limitations including restricted bandwidth, a limited dynamic range, and high sensitivity to load impedance mismatch. In emerging 5G systems, fluctuation of the antenna impedance is inevitable due to beamforming and steering using large antenna arrays. In this presentation, I will introduce a series of load-insensitive load-modulation PAs based on quadrature-balanced topology, including quasi-balanced Doherty PA (QB-DPA) and load-modulated balanced amplifier (LMBA). By leveraging quadrature balance and intrinsic varactor-less reconfigurability, the QB-DPA and LMBA can both maintain the wideband efficiency and linearity performance against arbitrary antenna impedance variations up to 3:1 VSWR. Moreover, a novel load-modulated double-balanced amplifier (LMDBA) will be presented, which is endowed with an inherent isolation from the antenna. This innovation holds promise for eliminating the need for magnetic circulators that are widely deployed in current 5G massive MIMO systems.

Speaker’s Bio: Dr. Kenle Chen received the Ph.D. degree in Electrical Engineering from Purdue University, West Lafayette, Indiana, USA, in 2013. He is currently an Assistant Professor with the Department of Electrical and Computer Engineering at the University of Central Florida, Orlando, FL. His research interests include ultra-efficient and wideband power amplifiers, AI-assisted RF circuits and systems, and heterogeneous integration of radio system in package. Prior to his career in academia, he worked as Principle/Lead RFIC engineer with several industry-leading companies, such as Skyworks Solutions Inc., where he focused on the development of advanced RF front-ends for various emerging wireless platforms.

Dr. Chen received the NSF CAREER Award in 2023, and his group has won multiple prestigious research-based awards, including First Place Best Paper Award of IEEE MTT-S International Microwave Symposium (IMS) 2020, three Best Paper Awards in IEEE Wireless and Microwave Conference (WAMICON), and four times of First Place Awards in IEEE MTT-S Student Design Competitions from 2018-2021. He has also been serving as Associate Editor of IEEE Transactions on Microwave Theory and Techniques, IEEE MTT-S Adcom Regional Coordinator, TPC Chair, and Steering Committee Member of multiple IEEE conferences.