Novel Beam-Forming Technology for WPT System to Flying Drone

We are developing the microwave power transfer (MPT) system for the flying drone and designing an optimum beam form to maximize the MPT efficiency, consisting of a beam efficiency from a transmitting antenna to a receiving antenna and an RF-DC conversion efficiency at a rectenna, rectifying antenna. Some beam-forming technologies exist to increase the beam efficiency but we do not mind the beam pattern at the receiving antenna surface. The RF-DC conversion efficiency of the rectenna has an input microwave power dependence and has an optimum microwave input power for maximum efficiency. If there is an amplitude taper at the receiving antenna surface in the maximum beam efficiency case, it is suitable for a signal transfer but not for the MPT because the RF-DC conversion efficiency of the rectenna is not maximum. We, therefore, propose a flat-top beam pattern to increase efficiency, which is beam efficiency × RF-DC conversion efficiency. We apply the Woodward Lawson method to make the flat-top beam.