Study of flat beam in near-field for beam-type wireless power transfer via microwaves

This study proposes a simple method for creating flat beam patterns in a near-field. In radio-wave transmission, the near-field beam efficiency of the beam-type wireless power transfer (WPT) system theoretically reaches 100%, but the beam pattern is not flat in the near field. In real beam-type WPT systems, the total beam efficiency (DC-RF-transmission, beam efficiency, and RF-DC conversion) can be improved by increasing the RF-DC efficiency of the rectenna. However, the rectenna requires a flat beam pattern in the near-field. In the present study, we create a flat beam pattern in the near field of a multicopter assisted wireless batteryless sensing system.