Analysis of electric and magnetic coupling components for spiral resonators used in wireless power transfer

Wireless power transfer (WPT) is required to be immune to the dielectric materials in its many potential applications. This paper evaluates the immunity of 3 kinds of spiral resonators by studying their electric and magnetic fields. The analysis of electric and magnetic fields is first carried on the single spiral resonator, and then on the coupled spiral resonators. It is shown that a lumped capacitor-connected and a double-spiral structure can effectively enclose the electric fields within them compared with a simple open spiral resonator. They have little electric field out of the resonator, and thus, they are immune to the dielectric materials.