Multiple resonators architecture is widely applied in wireless power transfer (WPT) systems, such as relay coils and metamaterials to increase the coupling coefficient, transmission efficiency and distance. However, the addition of extra LC resonators undoubtedly influences the overall performance of the whole system. In this paper, an analysis methodology is proposed to investigate the resonant frequencies and the response to external excitations of the WPT system, which is equipped with multiple resonators based on the similarity of multi-degree-freedom vibration equation and multi-resonators' circuit equation. In addition, some case studies applying the proposed method and the corresponding analysis results are presented. Similarities and differences between relay coils and metamaterials are discussed.

metamaterials;multiple resonators;relay coils;resonance analysis;wireless power transfer system