An efficient, linear, broadband class-J-mode PA realised using RF waveform engineering

Results from a fully implemented class-J RFPA (RF power amplifier) are presented for the first time, which demonstrate this mode's high efficiency potential across a substantial bandwidth. Using a commercially available 10W GaN (gallium nitride) HEMT device, and the high power waveform measurement and active load-pull capability at Cardiff University, class-J operation has demonstrated drain efficiencies between 60-70% across a 1.35-2.25 GHz (50%) bandwidth whilst delivering 10 Watts of power at the 2dB compression point. Realisation of the design has confirmed that the optimum harmonic load impedances of the class-J amplifier are more practically realisable than conventional class-AB modes, with better compromise between power and efficiency tradeoffs over a substantial RF bandwidth.