Satellite Communications in Japan

This paper describes recent research and development of satellite communication technology in Japan together with the future prospects. Newly developed earth station facilities for both commercial and experimental purposes are described first. New satellite communication systems, such as STAR, SMAX, TTT, SSB-PM, and SSRA, which originated and/or have been studied extensively in Japan, are described briefly. Recent developments of microwave and millimeter-wave antennas, parametric amplifiers, high-power tubes, etc., are surveyed. Brief descriptions are also given of radio-wave propagation studies and development plans for Japanese communication satellites.