Inverse Class-F AlGaN/GaN HEMT Microwave Amplifier Based on Lumped Element Circuit Synthesis Method

A lumped element design method considering more than third-order higher harmonic frequencies for a microwave AlGaN/GaN HEMT inverse class-F amplifier has been developed. The load circuit consists of a series reactance network having zero impedance at the odd order harmonic frequencies and poles at the even order higher harmonic frequencies as well as a shunt reactance network having zero impedance at the odd order harmonic frequencies. A fabricated AlGaN/GaN HEMT inverse class-F amplifier delivered a power-added efficiency of 76.3% and a drain efficiency of 78.3% at 879 MHz.