Circuit Modeling of a Wireless Power Transfer System by Eigenmode Analysis Based on the Impedance Expansion Method

The impedance expansion method (IEM), which has been previously proposed by the authors of this paper, is a circuit modeling technique for electrically very small devices. This paper describes a circuit modeling procedure that utilizes the IEM and eigenmode analysis for a wireless power transfer system. First, a multimode circuit model that can represent the higher order resonances in a broadband frequency range is presented. Subsequently, a single-mode circuit model-consisting only of passive elements-that can represent both the radiated and conduction loss powers at approximately its operating frequency band is presented.