Frequency effects of coil locations on wireless power transfer via magnetic resonance coupling

The wireless system with four coil resonators is a popular configuration for mid-range wireless power transfer via magnetic resonance coupling. The locations of four coils have strong impact on efficiency, resonant frequency and bandwidth of the wireless power transfer system. In this work, a comprehensive study on frequency effects of coil location parameters, such as the distances between neighboring coils, is conducted by virtue of full-wave electromagnetic solution. It is shown that the distance between the driving and transmitting coils may merely affect the bandwidth and the resonant frequency in the strong coupling regime. The distance between the transmitting and receiving coils can have strong impact on both the bandwidth and the resonant frequency. The research will provide design guidelines for optimal coil locations of the wireless power transfer system.