Distortion contribution analysis of an LDMOS Doherty power amplifier

This paper presents a distortion contribution analysis of a 100 watt LDMOS RF Doherty power amplifier. The analysis is performed using recently developed distortion contribution analysis technique called as Volterra-on-top-of-harmonic-balance that is able to show the originating cause of nonlinearity and mixing mechanisms between harmonic bands. The analysis shows that the nonlinear output capacitance of the carrier amplifier is the main cause of distortion at peak power levels.