A Fully Integrated Reconfigurable Multi-Mode Class-F2,3 GaN Power Amplifier

In this paper, we propose a reconfigurable multi-mode fully integrated power amplifier (PA) in GaN technology. The PA is composed of one main transistor, biased in class-AB, and three auxiliary transistors which can be switched between class-AB and deep class-C, to improve efficiency and linearity of the PA. Furthermore, a harmonic termination network is proposed to enable operation of the PA in class-F2,3. A proof-of-concept PA, fabricated using a 250-nm GaN-on-SiC process, provides 33.8 dBm output power and 42% peak drain efficiency (DE) at 4.8 GHz. Modulated-signal measurements using a 200-MHz 256-QAM 7.2-dB peak-to-average power ratio (PAPR) signal indicate that rms error vector magnitude (EVMrms) < 5% (–26 dB) can be achieved with 27.7–28.5 dBm average output power, 26–30% average DE, and –38.1 to –33.5 dBc adjacent channel leakage ratio (ACLR), in the four operation modes. It is shown that ACLR can be improved by 6 dB at lower output power levels through reconfiguring the mode of PA operation.