Development of high efficient phased array for microwave power transmission of Space Solar Power Satellite/Station

The SPS (Space Solar Power Satellite/Station) is most huge and important application of the wireless power transmission via microwaves. In 1960´s, the microwave power transmission (MPT) experiments were carried out by Dr. W. C. Brown[l], for example, MPT fro a helicopter, MPT in 1.6km distance with 450 kW Klystron, and Highest efficient MPT experiment in laboratory with magnetron of 54% DC-microwave-DC conversion efficiency. Based on the Brown´s experiments, the SPS was proposed in 1968 by P. E. Glaser[2]. In Japan, Prof. Hiroshi Matsumoto conducted many field and space MPT experiments from 80´s[3]. However, there is no commercial MPT application in 21st century because of the antenna size and cost. The most important benefit of the MPT is ´wireless´. Therefore we need a high efficient and low cost phased array as a power transmitter to control the beam direction for the effective commercial MPT system and the SPS. Especially for the SPS, we need ´higher efficient´ ´higher accurate´ ´lighter weight´ ´lower cost´ phased array with ´huge number of antenna elements´. However, there was no suitable phased array and no project of developing the phased array for the MPT. Recently in Japan, there are some trials of development of the special phased array for the SPS and MPT.