Characteristic Analysis on Double Side Spiral Resonator ’ s Thickness E ff ect on Transmission E ffi ciency for Wireless Power Transmission

Wireless power transmission using magnetic resonant coupling through the utilization of helical and spiral inductors offers the capability to potentially eliminate the “last wire” in power supply applications. In this paper, we will focus on double-side spiral resonators and especially on how their spacing affects the transfer efficiency between the two resonators. We fabricated double-side spiral resonators with different thicknesses and conducted measurement of the transmission efficiency-distance feature with two resonators connected to different ports of vector network analyzer, located in coaxial positions. We observed the measurement results that the thickness of double side spiral resonators affects the over coupled peak transmission efficiency, critical coupled transmission efficiency as well as the critical coupled distance between two resonators. We also conducted equivalent circuit analysis on the explanation of the thickness effect of double side resonator’s transmission efficiency at different distance ranges.