Annual Deep-Space Flight Operation Verification of X-Band GaN SSPA

An X-band, Gallium nitride (GaN)-based solid-state power amplifier (SSPA) was demonstrated for more than one year in deep space for the first time. The SSPA consisted of three-stage amplifiers and commercial off-the-shelf (COTS) GaN high-electron-mobility transistors (HEMTs) were used in both the second- and the final-stage amplifiers. During its one year of continuous operation, the GaN SSPA improved equivalent isotopically radiated power with low power consumption such as an average output power of 41.7 dBm (14.8 W), average power consumption of 43.5 W, and average efficiency of 33.7%. In addition, the deterioration rate of output power calculated from the inclination of the linear approximation line was no more than -0.08 dB per year. These results stand comparison with the results of high-temperature, long-term continuous operation test or a total ionizing dose test conducted on the ground. This paper illustrates the space applicability and reliability of the SSPA using a COTS GaN HEMT.