Phased array antenna systems for commercial applications in Japan

This paper will review research-level phased array activities and developed phased array systems in Japan. Two basic technologies for the beamforming networks are discussed, one is microwave processing technology using MMICs and the other is optical processing. Optically controlled phased array antennas utilizing optical components are described. As the commercial available systems, the airborne phased array antenna for INMARSAT-M, and the beam-switching train antenna on the Shinkansen are described. Several systems which have been investigated and not used for the commercial systems are also discussed. These are the S-band beamforming network for inter-satellite links (ISL), the secondary surveillance radar antenna, the multibeam forming network for future mobile satellite systems, and the mechanically steered planar antenna installed on the Shinkasen for DBS.