Analysis and implementation of inverse class-F power amplifier for 3.5GHz transmitters

In this paper, a theoretical analysis of inverse class-F power amplifier is carried out based on maximally flat drain current and voltage waveforms with the third-harmonic current and second-harmonic voltage peaking. The transistor is modeled as a switch in analysis, in which including non-zero switch-on resistance in parallel with an output capacitance. Therefore, the equations of drain efficiency and output power are derived. An inverse class-F power amplifier for 3.5GHz transmitter application based on CGH40010 GaN HEMT is designed and measured in this paper. Experimental results show that over 70% maximum drain efficiency and around 40dBm output power can be achieved. And a good broadband performance of the fabricated amplifier is also presented.