Multi-Level Chireix Outphasing GaN MMIC PA

This paper presents the design and performance of a 9.7 GHz GaN MMIC Chireix outphasing PA with discrete supply modulation. This architecture is referred to as Multi-Level Chireix Outphasing (ML-CO). The internal PAs include class-F harmonic terminations, while the Chireix combiner provides the fundamental frequency load modulation. A peak output power of 37 dBm (5W) is achieved, while a peak η_tot of 60.2 % is reached at 35.7 dBm. The average total efficiency calculated for a 6 dB PAR QPSK signal is 48.1 %, a 15.5 point improvement over the constant supply case.