Japan’s project for the research and development of active phased array antennas for practical applications

Recently, microwave frequencies have been forecasted to become tighter due to the rapid growth of communication systems in the world. In order to solve this situation, the frequency band from 6 GHz to 30 GHz which is called high microwave band is promoted for positive utilization by the Ministry of Internal Affairs and Communications (MIC) in Japan. Main applications are assumed to be mobile applications, satellite communications and wireless LAN. One of the promising key technologies for those systems is active phased array antennas (APAA) which have the agility of advanced beam control. Phased array antennas (PAA) have been vigorously utilized in radars. On the other hand, there were many attempts to use phased array antennas in communications due to the agility in radiation beam control, but most of them were not put into practical uses.