Input harmonics control using non-linear capacitor in GaAs FET power amplifier

We address the effect of gate signal distortion arising from capacitance non-linearity on the power added efficiencies of power amplifiers based on FETs. A novel method which can compensate the non-linearity of gate capacitance is proposed. The key idea is that a reversed diode is connected to the gate, where the gate and source part of a FET is simply modeled as a diode. We demonstrated this scheme with the load-pull and source-pull measurement of the circuit. A 7% increase in power added efficiency is achieved.