Analysis of $S$-Parameters in Magnetic Resonance WPT Using Superconducting Coils

After Prof. Marin Soljacic of Massachusetts Institute of Technology proposed the magnetic resonance wireless power transfer (WPT) in 2007, magnetic-resonance-type WPT has been tried to be applied to various charging equipment. The need for research of magnetic resonance WPT technology is increasing owing to the expectation on its application to electric vehicle and electric railway. In this paper, we used the superconducting coil in order to improve the transmission efficiency of the magnetic resonance WPT system. We found that the superconducting coil indicated higher transmission efficiency and Q-factor bigger than that of the normal conductor coil through the analysis of the S-parameters between the superconductor and normal conductor coils. If this research will be continued, it is expected to be applicable to high-power transmission systems.