Stacked Metasurfaces for Misalignment Improvement of WPT System Using Spiral Resonators

The conventional inductive wireless power transfer (WPT) systems have a trade-off between transmission distance and size. Furthermore, when the transmitter and receiver go away from the line of sight, the performance due to this so-called misalignment will sharply drop. In this work, a new type of metasurfaces called stacked metasurface is proposed, and its effectiveness to mitigate above problems are studied experimentally. As a result, by using the proposed metasurface, we succeeded in achieving a transmission distance between the transmitter and the receiver of 70 mm, which is more than double than its original transmission distance without the metasurface when the maximum efficiency occurs. At this enhanced transmission distance, the efficiency of the WPT system has improved from 2% to 60%.