Improved wireless power transfer efficiency with non-perfect lenses

Negative refractive index metamaterials (MMs) have found widespread interest in shaping electromagnetic waves. One attractive area is energy transfer using low frequency magnetic waves or wireless power transfer (WPT). Previous reports have presented an isotropic metamaterial with mu(r) = -1 as a perfect lens to focus energy and enhance WPT efficiency. In this work, we show that, while the perfect lens condition does enhance efficiency, anisotropic MMs with mu(r )not equal -1 can provide a larger enhancement in efficiency. These non-perfect lenses offer higher efficiency by enhancing the coupled field while incurring lower losses in the magnetostatic waves excited in or on the materials. Published under license by AIP Publishing.