A Comparative Study Between Novel Witricity and Traditional Inductive Magnetic Coupling in Wireless Charging

TLDR

The study proposes Witricity, a non‑radiative energy transformer that uses strong coupling between two medium‑range coils to achieve efficient wireless energy transfer. Witricity transfers energy by coupling the resonant‑field evanescent tails of two resonators at medium distances, behaves like conventional inductive coupling when off‑resonance, and its performance was evaluated through finite‑element analysis and experiments. Compared with typical magnetic inductive coupling devices, Witricity’s efficiency is much higher, demonstrating its feasibility for recharging batteries, especially in implant devices.

Abstract

A non-radiative energy transformer, commonly referred as Witricity and based on `strong coupling' between two coils which are separated physically by medium-range distances, is proposed to realize efficient wireless energy transfer. The distance between the resonators can be larger than the characteristic sizes of each resonator. Non-radiative energy transfer between the first resonator and the second resonator is facilitated through the coupling of their resonant-field evanescent tails. The proposed system operates as traditional inductive magnetic coupling devices when the operating frequencies are not the resonant frequency. Corresponding finite element analysis (FEA) and experiments have been carried out to facilitate quantitative comparison. Compared with typical magnetic inductive coupling energy transmission devices, the efficiency of the proposed system is much higher. This investigation indicates that it is feasible to use wireless energy transfer technology to recharge batteries, particularly in implant devices.