A Dual-Band Negative Permeability and Near-Zero Permeability Metamaterials for Wireless Power Transfer System

A contactless energy charging platform is an emerging technology that can improve the conveniences of electronic charging devices. This article presents a novel asymmetric wireless power transfer (WPT) system by integrating with two kinds of dual-band metamaterials, which is suitable for recharging the portable electronic devices. The design key of the metamaterial is to achieve the dual-band negative permeability (DB-MNG) and near-zero permeability (DB-MNZ) for enhancing efficiency and reducing leakage magnetic field of the WPT system, simultaneously. Especially, the corresponding simulation and experimentation are carried out to verify the validity of the DB-MNG metamaterial for increasing the efficiency at 13.56 and 27.12 MHz. Moreover, considering the charging environment of portable devices, various misalignments between the device and DB-MNG metamaterial are discussed to maintain continuous power availability. Meanwhile, the dual-band shielding performance of DB-MNZ metamaterial is proved at 13.56 and 27.12 MHz. As a result, the DB-MNZ metamaterial shield performs better than ferrite sheet and its performance is similar to that of aluminum sheet.