DEVELOPMENT OF MULTIBEAM PHASED-ARRAY ANTENNA ON ETS-VI FOR S-BAND INTERSATELLITE COMMUNICATIONS

This paper describes the S-band intersatellite communication (SIG) ant enna to be carried on the Engineering Test Satellite VI scheduled for launch in 1994, to undertake the first intersatellite data relay exper iments in Japan. The SIC antenna is an on-board formed multibeam phase d array antenna, the first of this kind in the world to be carried on a satellite. The SIC antenna is capable of simultaneous data relays to several orbiting satellites (user satellites) by means of an electric ally scanned beam. With an on-board microprocessor, the location of a user satellite can be computed, and the beam is pointed toward that di rection automatically. In comparison with the system used in the data relay satellite of the United States, the oil-board beam-forming syste m has several advantages, such as the effective use of power and frequ ency in the case in which the number of user satellites is small, as i n Japan. In this paper, the function and the configuration of an SIC a ntenna are described first. Next, analysis of the antenna is presented , including the effect of the phase and amplitude errors caused by tem perature fluctuations. Further, as the main components, the newly deve loped broadband microstrip antenna, a small beam-forming network with small phase errors, and the phase shifter controller making the comput ation of the orbit of the user satellite are presented. Finally. the t otal test results of the on-board model of the SIC antenna are describ ed.