Mutual Inductance Calculation of Two Coaxial Solenoid Coils with Iron Core

Abstract

This paper studies the mutual inductance between a pair of coaxial solenoid coils for wireless power transfer applied in implantable devices. This inductively coupled solenoid coil system, compared with the traditional antenna system, has an iron core introduced in the receiving coil for enhancing the inductive magnetic flux linking the coil. It allows transferring the power in the kHz range rather than the MHz range which normally requires a pure air core receiving coil, and hence it is a safer solution to human body. A simple analytical method for calculation of the mutual inductance as the key parameter in the wireless power transfer system is presented in this paper. The results are validated by Finite Element Method as well as experimental results.