抄録
The digital satellite broadcasting in JAPAN was started by JCSAT-3 (128 degree of east longitude) in October, 1996. Another digital satellite broadcasting will be started in April, 1998 by JCSAT-4 (124 degree of east longitude). The angle of orbital separation between JCSAT-3 and JCSAT-4 is 4 degrees. We've developed the essential technologies of "Overlap-Dual-Feed" and "Feed-Cap with Protrusion" for Dual Beam Antenna. We've completed design of a small size (Diameter=40cm) Dual Beam Antenna to receive services by both JCSAT-3 and JCSAT-4 ("JCSAT-3/JCSAT-4-DBA").
