30/20 GHz band transponder performance for Japanese Communications Satellite CS-3

This paper describes the configuration, electrical performance, and environmental compatibility of the newly developed 30/20 GHz band transponder. A single-conversion transponder is introduced instead of the double-conversion transponder employed in the CS-2 to reduce size and weight. A 30 GHz band low noise amplifier, a 30/20 GHz band down-converter, and a 20 GHz band amplifier were developed using GaAs FETs and GaAs diodes to realize a 30/20 GHz band lightweight MIC receiver. The K-band TWTA provides 10 W output power and utilizes an impregnated cathode to insure long cathode life. Dual-collector and velocity tapering techniques are introduced to improve DC-to-RF power efficiency.