Wireless power transfer for mobile devices with consideration of ground effect

Abstract

In this study, a wireless power transfer (WPT) system including three coils and working at 6.78 MHz is investigated. By employing a 2 × 3 metamaterial (MTM) array, the efficiency of the proposed WPT system is significantly enhanced. Experiments show that with the MTM array, a maximum efficiency improvement of 27 % is achieved at transfer distance of 35 cm. The impact of ground plane on the transfer efficiency is also studied. Several methods to reduce this impact are discussed and measured.