Free-Positioning Multi-Receiver Wireless Power Transfer System Based on Metasurface

Free-positioning and multi-user supportive wireless power transfer systems represent the next-generation technology for wireless charging of compact electronic devices. Here a metasurface for a free-positioning multi-receiver wireless power transfer system operating at the frequency of 6.78 MHz is proposed and numerically studied. Power transfer efficiency to a single receiver located in the center of the metasurface reaches 90%. We numerically demonstrate a high robustness of the proposed WPT system to the displacement of the receiver over the transmitter. At any free position of the receiver, the simulated power transfer efficiency is higher than 77%. We also numerically confirm the ability of simultaneous charging of two receivers on the metasurface. In this case, the overall efficiency remains high and reaches 91 % However, we note that the distribution of transferred power between the receivers is uneven and depends on their specific location and the coupling coefficient with the metasurface.