Rectifier Circuit using High-Impedance Feedback Line for Microwave Wireless Power Transfer Systems

Tomohiro SEKI
Yasunori SUZUKI

IEICE TRANSACTIONS on Electronics   Vol.E104-C    No.10    pp.552-558
Publication Date: 2021/10/01
Publicized: 2021/03/30
Online ISSN: 1745-1353
DOI: 10.1587/transele.2021MMP0009
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technologies)
wireless power transfer,  rectifier circuit,  feedback line,  microwave frequency,  quasi-millimeter and millimeter-wave frequency,  

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Research on wireless power transmission technology is being actively conducted, and studies on spatial transmission methods such as SSPS are currently underway for applications such as power transfer to the upper part of steel towers and power transfer to flying objects such as drones. To enable such applications, it is necessary to examine the configuration of the power-transfer and power-receiving antennas and to improve the RF-DC conversion efficiency (hereinafter referred to as conversion efficiency) of the rectifier circuit on the power-receiving antenna. To improve the conversion efficiency, various methods that utilize full-wave rectification rather than half-wave rectification have been proposed. However, these come with problems such as a complicated circuit structure, the need for additional capacitors, the selection of components at high frequencies, and a reduction in mounting yield. In this paper, we propose a method to improve the conversion efficiency by loading a high-impedance microstrip line as a feedback line in part of the rectifier circuit. We analyzed a class-F rectifier circuit using circuit analysis software and found that the conversion efficiency of the conventional configuration was 54.2%, but the proposed configuration was 69.3%. We also analyzed a measuring circuit made with a discrete configuration in the 5.8-GHz band and found that the conversion efficiency was 74.7% at 24dBm input.