Accurate and Efficient Method for Analyzing the Transfer Efficiency of Metasurface-Based Wireless Power Transfer System

An accurate and efficient calculation method for analyzing the transfer efficiency of a metasurface-based wireless power transfer system (ATEMWS-method) is proposed in this article. According to the amplitude and phase compensation information of the metasurface units (MUs) and using the superposition of the radiated electric field of each MU, the ATEMWS-method can calculate the wireless power transfer (WPT) efficiency from the metasurface to the energy harvester in any case. WPT systems based on a transmissive metasurface with a focused beam and a reflective metasurface with a high-gain directional beam are simulated to verify the method's effectiveness and correction. The results show that the proposed method has high accuracy in evaluating the WPT efficiency and dramatically improves the near-field accuracy by more than 70% compared with traditional methods. To further verify the accuracy of the ATEMWS-method in the near-field region, WPT systems based on transmissive and reflective metasurfaces with focused beams are fabricated to compare the experimental measurement and calculation results. The calculated results of the proposed method are particularly close to both simulated and measured values with a relative error of less than 0.5%, while it takes only one-thousandth of the simulation time by the commercial software. Due to its accuracy and convenience, the proposed method provides guidance and simplifies the design difficulty for the metasurface-based WPT system.