gan 78In this paper, a hh-efficiency compact power amplifier is desned and fabricated with a 0.25 μm GaN hh electron mobility transistor (HEMT) to meet the demands of a hhANTPS-78. ANTPS-78 is a long-range S band (IEEE desnation) or in the EF band (NATO desnation) air surveillance radar desned for detection of hh-speed and hh-altitude targets in challenging environmental conditions..