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Resumen

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 discussed, followed by an explanation of continuous-mode operation.  Techniques for high-efficiency linear amplification are also described.  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.

Frederick H. “Fritz” Raab is Chief Engineer and Owner of Green Mountain Radio Research, an 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 MTT-S Pioneer Award in 2019.  He is coauthor of the classic textbook Solid State Radio Engineering and over 100 technical papers.  He was program chairman for RF Expo East ’90 and founded technical committee MTT-20 that expanded the MTT-S to include HF/VHF/UHF engineers.  He is a member of IEEE, Eta Kappa Nu, Sigma Xi, AOC, RCA (fellow), and ARRL.  “Fritz” is an extra-class amateur-radio operator W1FR (licensed since 1961) and was coordinator of the ARRL 500-kHz experiment which was instrumental in gaining the new 630-meter amateur band.