Beam Control Technologies With a High-Efficiency Phased Array for Microwave Power Transmission in Japan

Beam control and/or beamforming technologies involving phased arrays can be used to enable highly efficient microwave power transmission (MPT) systems. In Japan, several field MPT experiments using a phased array have been conducted over the years. In 1992, a joint collaborative group successfully conducted a fuel-free flight experiment using phased-array technology, which was referred to as the MIcrowave Lifted Airplane eXperiment. In 2008, Kobe University (Kyoto, Japan) and a U.S. research group successfully conducted an MPT experiment using a phased array that resulted in power transmission over a distance of 150 km. Furthermore, Kyoto University proposed and demonstrated a magnetron-based phased array and conducted MPT from an airship to the ground in spring 2009. In FY2010, Kyoto University developed new highly efficient phased arrays for MPT and solar power satellites. This study provides an overview of past and present Japanese MPT experiments using phased-array technologies.