A C-band 55% PAE high gain two-stage power amplifier based on AlGaN/GaN HEMT*Project supported by the National Key Basic Research Program of China (Grant No. 2011CBA00606), Program for New Century Excellent Talents in University, China (Grant No. NCET-12-0915), and the National Natural Science Foundation of China (Grant No. 61334002). (20th September 2015)