Metamaterial-Enhanced Coupling between Magnetic Dipoles for Efficient Wireless Power Transfer

TL;DR

This paper introduces a metamaterial-based system that significantly enhances wireless power transfer efficiency between magnetic dipoles by using a superlens, with theoretical analysis showing potential for practical improvements.

Contribution

It presents a novel near-field metamaterial superlens system for wireless energy transfer, including detailed theoretical modeling and efficiency analysis.

Findings

Power transfer efficiency can be increased by an order of magnitude with the metamaterial slab.

Efficiency remains high even with realistic magnetic losses.

Metamaterial volume can be greatly reduced using high anisotropy permeability.

Abstract

Non-radiative coupling between conductive coils is a candidate mechanism for wireless energy transfer applications. In this paper, we propose a power relay system based on a near-field metamaterial superlens, and present a thorough theoretical analysis of this system. We use time-harmonic circuit formalism to describe all interactions between two coils attached to external circuits and a slab of anisotropic medium with homogeneous permittivity and permeability. The fields of the coils are found in the point-dipole approximation using Sommerfeld integrals, which are reduced to standard special functions in the long-wavelength limit. We show that, even with a realistic magnetic loss tangent of order 0.1, the power transfer efficiency with the slab can be an order of magnitude greater than free-space efficiency when the load resistance exceeds a certain threshold value. We also find that the volume occupied by the metamaterial between the coils can be greatly compressed by employing magnetic permeability with a large anisotropy ratio.