Dual-Band Multi-Receiver Wireless Power Transfer with Reactance Steering Network

Wireless power transfer (WPT) via near-field magnetic coupling is an enabling technology for many applications including consumer electronics and electric vehicles. A few WPT standards have been established with frequencies ranging from kHz to MHz. MHz operation offers smaller size and higher tolerance to coil misalignment, and kHz operation offers higher efficiency and higher power rating. This paper presents a dual-band multi-receiver (DBMR) WPT architecture targeting applications with very wide load impedance variation. The key innovation is a novel reactance steering network (RSN) that can seamlessly compensate an arbitrary load impedance for radio-frequency (RF) power amplifiers. The proposed approach is generally applicable to a variety of high-frequency power conversion applications. A dual-band reconfiguable WPT system that can efficiently power multiple 100 kHz and 13.56 MHz receivers across a very wide misalignment range is built and tested to validate the proposed RSN technique.