Spiral Resonator Arrays for Misalignment Compensation in Wireless Power Transfer Systems

In this contribution, the authors focus on the use of a metasurface (physically implemented as a 2D array of spiral resonators) as an additional component of a two-coil Wireless Power Transfer (WPT) system, with the aim of increasing the robustness to misalignment between the transmitter and the receiver coils. Resonator arrays have been proven to have a positive effect on WPT systems' performance since they produce a focus-ing effect on the magnetic field; at the same time, they contribute to the reduction of the electric near field. In addition, we herein demonstrate how proper control over the metasurface's unit cells can contribute to making a WPT system more tolerant to misalignment. In partic-ular, the comparison between metasurfaces of different sizes (keeping the same transmitting and receiving coils) and their optimization performed to improve misalign-ment robustness is proved by numerical simulations.