Reconfigurable Metasurface for Near-field Efficient Wireless Power Transfer System

Abstract: Wireless power transfer (WPT) offers a promising solution for powering distributed devices in smart cities, significantly simplifying system complexity and accelerating urban automation. In traditional WPT systems, far-field schemes are costly, energy-intensive, and ineffi⁃ cient, while near-field transmission offers higher efficiency but suffers from limited distance. To address the limited transmission distance of near-field WPT, this paper derives an electromagnetic model for WPT using reflective metasurfaces and presents the design of a high- performance 3-bit reconfigurable intelligent surface (RIS). Based on theoretical models, we investigate the effects of phase quantization and array size on focusing efficiency. Simulation results guide the subsequent fabrication of the RIS prototype. Experimental measurements on the fabricated prototype validate the beam-focusing effect and evaluate the overall WPT efficiency.

Keywords: reconfigurable intelligent surface; near-field beam focusing; wireless power transfer