Optimal Metamaterial Configuration for Magnetic Field Shielding in Wireless Power Transfer Systems

This paper investigates the use of a metamaterial slab for magnetic field shielding in a low-frequency inductive power transfer (IPT) system. In particular, three different configurations of metamaterial slabs are considered, which are defined assuming the same slab area, total copper wire length and weight. A 3x3, 5x5 and 7x7 array made of wound spiral coils with series-connected capacitors have been developed. They are compared based on the average shielding efficiency (SE) evaluated for a field-point grid at a certain distance from the metamaterial. Since the magnetic field close to the slab is in general non-uniform, the standard deviation of the grid-point SE has been introduced. Finally, the impact of the three different metamaterial slabs on the IPT system performance has been discussed considering the overall power transfer efficiency.