Optimization of double spiral metamaterial for wireless power transfer

Metamaterials (MMs) have been proposed to improve the performance of wireless power transfer (WPT) systems. However, optimization of WPT systems with MM using complex electromagnetic analytical methods and slow finite element simulation methods have become increasingly tedious. A simple analytical approach using equivalent circuit method to optimize WPT systems with MMs is proposed in this paper. A Double spiral metamaterial (DSM) is introduced and analyzed using the proposed approach. Furthermore, a detailed optimization process is presented considering system level performance indices (efficiency and transferred power) and application level requirements (transfer distance, maximum misalignment and probability of alignment). A novel figure-of-merit is introduced to achieve better compromise between system level performance indices and application level requirements. The proposed optimization strategy is validated with the experimental results.