Electrical design of BS-3 communication antenna

Abstract

This paper describes the electrical design of the shaped beam antenna for the next-phase Japanese broadcasting satellites (BS-3a, BS-3b) with some typical test results of an engineering model (EM). The BS-3a and BS-3b will be launched as successors to the BS-2 in 1990 and 1991, respectively, by an H-I launch vehicle. This antenna employs an elliptical offset parabolic reflector fed with a new-type elliptical corrugated horn and a rectangular horn with corrugation in the shorter sides. The major and minor axis lengths of the aperture are 1700 mm and 800 mm, which are somewhat smaller than that of the BS-2 antenna. The EM antenna has attained a gain of more than 39 db for the major parts of the Japan Islands, more than 36 db for Okinawa, and more than 28 db for the remote islands. The sidelobe and cross-polar components are verified to satisfy the WARC-BS requirements.