[IEEE 2012 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications (IMWS 2012) - Kyoto, Japan (2012.05.10-2012.05.11)] 2012 IEEE MTT-S International Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications - Shielded coil structure suppressing leakage magnetic field from 100W-class wireless power transfer system with higher efficiency