Self-outphasing Chireix power amplifier using device input impedance variation

Abstract

A new outphasing signal splitter for a radio frequency (RF) single input Chireix power amplifier without using digital signal processing is introduced. Input signal phase control versus power for outphasing operation is obtained by using only a linear circuit, exploiting the input impedance variation of non-ideal devices. A 52.6 dBm peak output power, 6 dB back-off Chireix power amplifier is built operating at 2.17 GHz. More than 50% drain efficiency is maintained over 5.7 dB output power back-off range.