Development of a 10-W-Class Microwave Power Source Based on a Dielectric Resonator Oscillator and Class-F Power Amplifier for a Microwave-Discharge Ion Thruster on LEO-Satellites

Recently satellites in low earth orbit (LEO) used for satellite communications (satcom) are entering a period of growth.LEO satellites are capable of operating their thruster systems to adjust their attitude and altitude in orbit. A recent development for thruster system uses compact microwave-discharge ion or Hall thruster technology with main advantage being the utilization of noble gas or water-vapor over traditional combustible fuels. Hence, the thruster system can operate with greater safety, cost-effectiveness, and a size reduction compared to other type of thrusters. Massive satellite constellation employing water vapor systems based on LEO satcoms could benefit during deployment and normal operations. The thruster system consists of an oscillator-stage, amplifier-stage, and a microwave-discharge ion thruster. To realize the advantages of a water-vapor based system, it is necessary to develop a high efficiency microwave power source (MPS). We developed a MPS with a dielectric resonator oscillator (DRO) and single class-F power amplifier with 10-W-class GaN power transistors. The oscillator can generate 1 W output during the amplifier-stage requires $1 \mathrm{~W}(30 \mathrm{dBm})$ input to operate and outputs 10 W microwave power at the most optimal power efficiency. In this report, we explain the development of 10-W-class MPS which is a 41.76 dBm maximum output at 4.2074 GHz with a system efficiency of $46.65 \%$. We also detail the environmental evaluations complied with space standard from the SMC-S-016.