High-Efficiency Power Amplifiers

Chireix. Doherty. Kahn. These names are widely heard throughout the power amplifier (PA) industry today when the discussion turns to high-power, high-efficiency amplifiers. When one hears “the Doherty PA is operating at 6 dB output power backoff (OBO) with a 6.5 dB peak to average power ratio,” most PA design engineers are interested in these and other important performance specifications, but what about the names behind the amplifiers themselves. Who were these engineers who have widely used communications amplifiers named after them? This article will attempt to shed a little light on the history behind these engineers and to provide an historical context behind their discoveries.