High-Efficiency Single- and Dual-Band Rectifiers Using a Complex Impedance Compression Network for Wireless Power Transfer

Abstract

In this paper, novel single- and dual-band complex impedance compression networks (ICNs) are proposed and applied to the design of rectifying circuits for efficiency improvement. The proposed ICNs are connected to the microwave input of two parallel subrectifiers. They reduce the variation ranges of the rectifier input impedance, which change with input power. Thus, the loss due to impedance mismatch is reduced, and high conversion efficiency can be obtained over wider input power ranges. Compared with the resistance compression networks (RCNs), the proposed ICNs are able to compress the variation range of the complex impedance, rather than that of the resistance, featuring design flexibility. A detailed analysis is carried out. For demonstration, a 2.45-GHz rectifier and a dual-band rectifier working at 2.45 and 5.8 GHz for the industrial, scientific, and medical band are implemented based on the ICN. The experimental results show that, in comparison to the counterparts without the ICN, the proposed rectifiers with the ICN can improve the efficiency at low input power levels without degrading the maximum conversion efficiency. Besides, the ICN-based rectifiers have a much simpler circuit structure than the RCN-based rectifiers.