L‐band high power solid‐state power amplifier for aerospace usage

Abstract This work presents the design, implementation, and experimental results of an L‐band solid‐state power amplifier (SSPA) developed for the next generation high‐power transmitter for the space usage. The microwave frequency nircuit (MFC) is realized by cascading a channel amplifier, a drive power amplifier (PA) and a high PA section. By utilizing the gallium nitride (GaN) HEMTs, the efficiency of the drive PA and high PA are improved to more than 70% over the frequency range from 1.45 to 1.55 GHz, which ensures an overall efficiency of the MFC higher than 66%. Then a high efficiency power‐supply based on the phase‐array bridge topology is proposed for voltage conversion and output sequence control, which delivers a high efficiency of about 94% at the rated power range. In the 100‐MHz operating bandwidth, the SSPA delivers more than 200 W of output power with an associated 3rd order intermodulation product (IM3) and power added efficiency (PAE) better than −18 dBc and 60%, respectively. The gain can be varied from 25 to 56 dB with a minimal step of 0.5 dB through telecommand, whereas the phase can be adjusted within 360° range with a minimal step of 5.6°.