Progress in the Efficiency of Free-Space Microwave Power Transmission*

ABSTRACTRecent developments in rectenna design and microwave beam launching have increased the ratio of the dc power output from the rectifier at the receiving point to the rf power input to the transmitting antenna from 0.41 to 0.60. The efficiency of microwave beam launching has been improved through the use of the dual-mode horn which has exceptionally low power loss in its side lobes. Improvement in the efficiency at the receiving point has resulted from increased capture efficiency of the rectenna.