A Comparison of SSPA and TWTA for Beidou Navigation Satellite System

This paper describes an L-band Solid State Power Amplifier (SSPA) and a Traveling Wave Tube Amplifier (TWTA), used in the Beidou Navigation Satellite System (BDS). The electrical performance of the SSPA and the TWTA is compared in the whole B2-band of BDS (i.e., f=1191±40 MHz). Under continuous-wave operations, both the SSPA and the TWTA can deliver an output power in excess of 150 W with overall efficiency, including the power consumption of the electronic power conditioner unit (EPC), higher than 50%. However, in terms of the nonlinear distortion, gain, mass, and volume, the SSPA has apparent advantages. In the test of B2-band modulated signal adopted in BDS, the results have shown that the SSPA has the less out-band parasitic power, less power loss and less efficiency degradation.