A 7.4 to 8.4 GHz high efficiency PHEMT three-stage power amplifier

This paper describes the design, fabrication, and performance of a 7.4 GHz to 8.4 GHz 3-stage PHEMT power amplifies. To the best of our knowledge, this amplifier has achieved the highest efficiency, power, and gain ever for a three-stage power amplifier at X-band. At a drain voltage of 6 volts, measured power added efficiency was between 50% to 60% with a CW power output of 35 dBm and an associated gain of 24 dB. The amplifier was stable over all measured biases and all drive levels.