Relay Effect of Wireless Power Transfer Using Strongly Coupled Magnetic Resonances

TLDR

Wireless power transfer via strongly coupled electromagnetic resonators is a recent technology that, while extending transmission distance beyond traditional near‑field methods, still falls short in some applications. The study investigates a relay effect to extend the energy transfer distance of strongly coupled resonator wireless power transfer. The authors analyze the relay effect using coupled‑mode equations and validate the theory with experiments that confirm its effectiveness. The relay approach significantly boosts power‑transfer efficiency, enhances the two‑resonator system’s performance, and enables curved‑path transfer with smaller resonators.

Abstract

Wireless power transfer using strongly coupled electromagnetic resonators is a recently explored technology. Although this technology is able to transmit electrical energy over a much longer distance than traditional near field methods, in some applications, its effective distance is still insufficient. In this paper, we investigate a relay effect to extend the energy transfer distance. Theoretical analysis is performed based on a set of coupled-mode equations. Experiments are conducted to confirm the theoretical results and demonstrate the effectiveness of the relay approach. Our results show that the efficiency of power transfer can be improved significantly using one or more relay resonators. This approach significantly improves the performance of the present two-resonator system and allows a curved path in space to be defined for wireless power transfer using smaller resonators.