Simple Dedicated Energy Beamforming in Random-Beamforming Distributed Microwave Power Transfer

A simple dedicated energy beamforming (DEB)scheme is described for random-beamforming (RB) distributed microwave power transfer. A suboptimum transmit phase set for an antenna subset is searched for based on time slot index feedback during operation of RB for a large number of implicit target devices distributed in wide areas. The DEB using the suboptimum transmit phase set and its randomly rotated versions maximize the received power in explicit target devices while randomizing interference in surrounding areas. Our simulation results demonstrate that our proposed DEB scheme achieved higher power transfer efficiency for explicit target devices during RB power transfer.