Enhanced efficiency of magnetic resonant wireless power transfer system using rollable and foldable metasurface based on polyimide substrate

This paper proposes a rollable and foldable metamaterial structure that can improve the efficiency of a magnetic resonant wireless power transfer (MR-WPT) system operating at 13.56 MHz. The metasurface is fabricated on a thin polyimide substrate with a thickness of 0.1 mm and positioned between the transmitter and receiver coils of the MR-WPT system. This allows the metasurface to be fully flexible, making it possible to roll it around a cylindrical bar or fold it to follow the misalignment angle of the receiver. The rollable and foldable metasurface makes the configuration of the MR-WPT system more flexible and compact, thereby increasing its applicability. Detailed investigations of the proposed MR-WPT system were conducted through simulation and experiment. The efficiency of the MR-WPT system can be significantly improved from 30 to 50.5% when the full metasurface is used. The proposed metasurface can be rolled and disappear, making it useful in situations where the MR-WPT system configuration requires high flexibility. Additionally, a foldable metasurface can improve the transfer efficiency of misalignment MR-WPT systems from 8.8 to 28.1% in the case of a misalignment angle of 30^o. Overall, this work presents a promising solution for enhancing the efficiency of MR-WPT systems and increasing their flexibility.