Investigation of Input-Output Waveform Engineered Continuous Inverse Class F Power Amplifiers

An in-depth analysis of the continuous inverse Class F power amplifier (PA) accounting for nonlinear input and output active device properties is presented. The analyses show possible ways of exploiting input nonlinearity to improve and maintain PA performance in a broadband operation and propose a flexible source second-harmonic design space which reduces the input matching network (MN) design complexities. Such exploitation of input nonlinearity can also alleviate performance degradation due to dynamic knee behavior of a practical field-effect transistor (FET) in continuous inverse Class F PA operation. The analyses are validated with vector load-pull (VLP) measurements and utilized to implement a broadband PA design. High-drain efficiency (DE) over 75% and output power more than 38 dBm are achieved over 0.8-1.4 GHz at constant 3-dB gain compression.