Abstract:  In response to the demands for microwave high power amplifier in satellite systems，an L-band 200W high-efficiency solid-state amplifier（SSPA）was developed and its design methods and key technologies were discussed.a highly integrated and miniaturized radio frequency unit（RFU）was realized with SSPA by using LTCC（low temperature co-fired ceramic）substrate.Based on the third-generation semiconductor devices，the power and efficiency of the RFU were improved by applying waveform shaping and linear compensation techniques.A high efficiency and high power secondary power supply was developed by using phase-shift-full-bridge（PSFB）topology.From 1.45GHz to 1.55GHz，the SSPA delivers more than 200W of output power with an associated 3rd order intermodulation product（IM3）and power added efficiency（PAE）better than 18dBc and 60% respectively.The gain can be adjusted within 30dB，whereas the phase can be adjusted within 360° range with a minimal step of 5.6°.The experimental results show that the SSPA is the most advanced with the highest power and efficiency in China.

Key words: L band, solid-state power amplifier, gallium nitride, high power, high efficiency, waveform shaping, phase-shift-full bridge