The seminar is held by Dr. Olof Bengtsson, Head of RF Power Lab at the Ferdinand-Braun Institut (Berlin).
Date: 29 SEPTEMBER 2022 from 14:00 to 15:00
Event location: Room 3.4 - Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi" DEI - Viale Risorgimento, 2 - Bologna
Type: Seminar
ABSTRACT
The introduction of GaN technology has triggered the development of various types of supply modulated systems based on switch-mode modulators. Discrete level supply modulation (class-G) where the supply voltage is switched at certain discrete envelope levels of the modulated signal reach state-of-the-art performance in terms of efficiency and instantaneous modulation bandwidth (IBW) for 4G wideband signals. Compared to continuously supplymodulated systems, a significantly lower switching frequency in the same range as the IBW, is required for the supply modulator. Integrated MMIC solutions with PA and switching stage on the same chip together with fast GaN diodes show promising performance to meet the future need of IBW. Work is now pursued to bring the class-G efficiency-enhancement topology into the 20 to 30 GHz range, in integrated solutions targeting space- and 5G-MIMO-applications. Another switch-based supply modulated system with promising performance is the reverse buck topology. Switching towards ground eliminates the need for an isolated gate driver which makes the switch faster with less delay. However, the RF PA is floating which requires special caution in the design. Here, the recently developed floating ground transistor makes floating ground PA development easier and improves the IFBW performance considerably.
BIO
Olof Bengtsson received the Ph. D. degree in 2008 from the Department of Solid-State Electronics (SSE), Ångström Laboratory, Uppsala University, Sweden, in 2008. Since April 2009 he is with the Ferdinand-Braun-Institut (FBH), Berlin, Germany where he currently holds the positions Head of the RF Power Lab and Group Leader for Microwave Measurements. His main interests are largesignal device characterization and high efficiency RF-power amplifier designs based on load and supply modulation.