Rectification Improvement With Flat-Topped Beams on 2.45-GHz Rectenna Arrays

This article proposes the application of microwave power transfer (MPT) with the drone. As a feasibility study, MPT experiments were conducted to a receiver 1.2 away from a transmitter at 2.45 GHz. We aimed to enhance the rectification efficiency of the MPT by array antenna beamformings, named flat-topped beams. We conducted power transfer experiments between the transmitting antenna and the receiving antenna, where a port-to-port efficiency of 31.4% was confirmed on the flat-topped beams. Using the measured illuminance distributions of flat-topped beams on a rectenna plane, we provided a detailed comparison of the rectification efficiencies between conventional uniform beams and the designed flat-topped beams. The obtained rectification efficiency of the series/parallel rectenna array was 68.5%/65.4% in the flat-topped beams and 60.8%/61.1% in the uniform beams. The results of the experiments revealed that the flat-topped beams almost exhibited no connection loss of the rectenna array. Based on the above results, there is a possibility to achieve a high overall efficiency of approximately 60% with the flat-topped beam MPT.