Recent phased array work in Japan

Phased array antennas for satellite communication, air navigation systems, radio astronomy, and remote sensing are discussed. The state of the art of phased array devices, such as phase shifters and active modules is reviewed. For satellite communication, an S band scanning single beam/fixed multibeam array, 30/20 GHz reflector-type multibeam antenna with array feed, and various array antennas for ground mobile terminals are described. For air navigation systems a design concept of cosecant beam with high aperture efficiency is introduced. A mm-wave five-element synthesis telescope, including technologies to maintain phase stability of the interferometer at 22/115 GHz, and middle and upper atmosphere radar are introduced.