Satellite communication systems are essential to realize highspeed and global services by virtue of their broadband performance and wide area coverage. However, current and planned Global Mobile Satellite Communication systems are aimed mainly at serving low-bit-rate voice, facsimile and data services with rates of up to about 4.8kbit/s. This channel rate, despite the use GEO, ME0 or LEO satellites, is too low to realize comfortablemobile computing such as Internet access, e-mail, remote LAN access, image transmission, and video-phone. However, phased array multibeam antennas with about 15m aperture deployable reflectors of S-band have been developed [ 11-[5]. Satellites with these antennas will be able to realize a small user terminal and higher speed data services with rates of up to 144kbit/s.