Efficiency Improvement by Electromagnetic Metasurface in Wireless Power Transfer System

The electromagnetic parameters of the electromagnetic metasurface (EMMS) can affect the performance of the wireless power transfer system. However, the method of the effective medium theory can not reveal the intrinsic physical properties of the system. The theory of EMMS with dual-frequency has not been investigated. And the EMMS apply to the wireless power transfer is hard to analyze and optimize. Therefore, this article proposed the circuit method to optimize the structure of EMMS. The mutual inductance between the unit cells in the arbitrary position is calculated. Additionally, the effective permeability of the EMMS with dual-frequency is deduced by the numerical calculation. The calculation results are consistent with the simulation results. And the magnetic field of the wireless power transfer system with EMMS can be enhanced. The experimental results show that the designed EMMS can improve the efficiency at two frequencies. Additionally, the design structure can adjust the electromagnetic field to achieve different performance. It is important to understand the working mechanism of the EMMS with dual-frequency.