Indefinite-permeability metamaterial lens with finite size for miniaturized wireless power transfer system

A miniaturized wireless power transfer (WPT) system using indefinite-permeability metamaterial (IPMM) lens with finite size is proposed and investigated theoretically and experimentally. Theoretical simulations show that the IPMM lens outperforms isotropic negative metamaterial (NMM) lens in terms of coupling efficiency and lens size. A highly sub-wavelength IPMM operation at high frequency was designed, fabricated, and measured. The WPT experiments show that the efficiency can be enhanced significantly from 0.7% to 22.0% when the system is loaded with IPMM lens around 4 MHz. The further study shows that the IPMM lens can extend the operating distance of WPT by using an optimization approach.