The Efficiency Improvement of Multiple Receivers in Wireless Power Transmission by Integrating Metasurfaces.

In this paper, we propose the use of metasurfaces to enhance evanescent wave coupling to improve the wireless power transfer (WPT) efficiency of multiple receivers. A 4 × 4 negative permeability metasurface is designed and placed between the transmitter (Tx) and receiver (Rx) coils for the greatest improvement in transfer efficiency. Through the analysis of the number and position topologies of Rx coils, the efficiency can be greatly improved; the maximum efficiency at longer transmission distances is achieved through the 4 × 4 negative permeability metasurface in the multiple-receiver system. We show with simulation and measurement results that the power transfer efficiency of the system can be improved significantly by integrating metasurfaces. The maximum transfer efficiency is achieved in a multiple-receiver WPT system when the number and topology of Rx coils is case 0 of single transmitter-three receivers (STTR). The results show that the total efficiency of the multiple receivers WPT system can be as high as 97%.