This is an IEEE Central Iowa SP/COMM/C&S Joint Chapter Event.
Speaker: Frederick H. Raab, Chief Engineering and Owner of Green Mountain Radio Research
Title: High-efficiency RF-power amplifiers and transmitters
Abstract: This talk is an overview of techniques for high-efficiency RF-power amplification. First, some basic concepts about transistors and the concept of average efficiency are introduced. The characteristics of conventional amplifiers (classes A, B, and C) are then reviewed. The principles, demonstrated achievements, and practical limitations of RF-power amplifiers operating in classes D, E, and F are then discussed, followed by an explanation of continuous-mode operation. Techniques for high-efficiency linear amplification are then discussed. These include the Kahn EER technique, envelope tracking, Doherty, and Chireix outphasing, as well as high-level amplitude modulators. Finally some notes on emerging techniques are offered.
Bio: Frederick H. Raab is Chief Engineer and Owner of Green Mountain Radio Research, a consulting/R&D firm which he founded in 1980. He received B.S., M.S., and Ph.D. degrees in electrical engineering from Iowa State University in 1968, 1970, and 1972. He received the I.S.U. Professional Achievement Citation in Engineering in 1995, was named an IEEE fellow in 2006, and received the IEEE MTT Pioneer award in 2019. The classic textbook Solid State Radio Engineering, coauthored by Dr. Raab was widely used and helped to educate a generation of RF engineers. Other professional achievements include publication of over 100 technical papers and award of twelve patents. He has served as technical program chairman for RF Expo East ’90 and founded technical committee MTT-17 that brought HF/VHF/UHF engineers into the expanded the IEEE MTT Society. He is a member of IEEE, HKN, Sigma Xi, AOC, RCA, and ARRL. “Fritz” is extra-class amateur-radio operator W1FR, licensed since 1961, and was coordinator of the ARRL 500-kHz experiment which was instrumental in securing the new 630-meter band. This is also an IEEE Central Iowa SP/COMM/C&S Joint Chapter Event.