C-band and X-band class F, F-1 GaN MMIC PA design for envelope tracking systems

A 4.5GHz Class F GaN MMIC power amplifier design is presented in this paper. The MMIC is designed to be used with an envelope tracking amplifier for efficiency enhancement. The characterization and modeling of a 6×100 um die for the power amplifier design to be used in an envelope tracking system is described and discussed. The design was fabricated in a 0.14 um GaN HEMT process. The results of an inverse Class F design at 10GHz fabricated in the same process are presented as well. The 32W inverse Class F design achieved 54.4% system drain efficiency at 6.6dB back-off, with a 20MHz 16 QAM LTE signal, the highest reported efficiency at 10GHz in signal back-off. The design, characterization and modeling provide new insight into the strategy necessary for the successful realization of envelope tracking power amplifiers.