The Impact of Self-resonance on Self-inductance and Mutual Inductance of Two Coils used for Wireless Power Transfer

Due to distributed capacitance, a planar printed coil has self-resonance, which will significantly affect self-inductance and mutual inductance. In this paper, the impact of self-resonance on self-inductance and mutual inductance of two coils is analyzed by the equivalent circuit, and the calculations of apparent self-inductance and apparent mutual inductance are derived. The analysis results can well explain the frequency characteristics of the planar printed coils' self-inductance and mutual inductance obtained by full-wave simulation. Finally, the correctness of the analysis results derived from the equivalent circuit has been verified by the numerical example.