Compact Hybrid Metasurface-Inspired Resonator With Uniform Magnetic Field Distribution for Wireless Power Transfer

Compact and safe charging platforms have been one of the main goals in wireless power transfer (WPT) research and development. Here, we propose a compact hybrid metasurface-inspired resonator with a uniform magnetic field distribution for WPT. It consists of two orthogonally oriented layers of parallel printed wires with high-permittivity dielectric pads between them. This design allows us to spatially separate electric and magnetic fields, which provide high WPT efficiency and electromagnetic safety simultaneously. The prototype with 28 cm x 28 cm working area with uniform magnetic field was fabricated and experimentally studied. The measured coefficient of variation of the magnetic field in the working area of the resonator is 6.8%. The maximum achievable WPT efficiency reaches 70% over the working area. The numerically assessed specific absorption rate in human tissues placed on the proposed structure is 11 mW/kg, which is 30 times lower than on a conventional planar spiral coil. Our results pave the way to compact and safe WPT platforms for one-to-many charging.