Qi Standard Compatible Metasurface for Multi-Device Wireless Power Transfer with Tunable Power Division

Multi-user wireless power transfer (WPT) systems represent the next-generation technology for mobile device charging under the Qi standard. To achieve this goal, conventional techniques typically employ a complex system with multiple transmitting coils and power electronic circuits with independent feeding channels. In this paper, we demonstrate a metasurface-enhanced WPT system capable of achieving this goal with a single transmitting coil. The metasurface passively reshapes the magnetic field into multiple beams at the receivers’ locations. We demonstrate to improve the dual-receiver efficiency from 55.9% to 71.9%. We also demonstrate tuning the power division between the receivers and compensating power differences to receivers of different sizes. The power ratio between a larger and smaller receiver is adjusted from 1:0.12 to 1:1.20 with the metasurface.