Outline and progress of the Japanese microwave energy transmission program for SSPS

Institute for Unmanned Space Experiment Free Flyer, USEF, has been studying Space Solar Power System, SSPS, as future electricity alternative energy source since 1990s. From 2009, USEF started research and development project of Microwave Ground Wireless Power Transmission under a support of Ministry of Economy, Trade and Industry, METI. This project plans to test ground wireless power transmission as a previous stage to the next space proof of SSPS. Also this project includes the study for high efficient and thin structured phased array antenna, and the study for high efficient rectenna element. In this paper, outline and progress of this project are introduced.