Department Seminar and IEEE Central Iowa SP/COMM/C&S Joint Chapter Event


Title: "High-efficiency RF-power amplifiers and transmitters"

Speaker: Dr. Frederick H. Raab

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.

  Date and Time




  • 2520 Osborn Dr
  • Ames, Iowa
  • United States 50011
  • Building: Coover Hall
  • Room Number: 3043
  • Click here for Map

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  • Co-sponsored by


Frederick Raab of Green Mountain Radio Research


High-efficiency RF-power amplifiers and transmitters


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 textbook Solid State Radio Engineering, coauthored by Dr. Raab, is widely used by both academics and practicing 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 foundedg technical committee MTT-17 that expanded the IEEE MTT Society to include HF/VHF/UHF engineers.  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.