1. Department of Electrical and Electronic Engineering, Xi’an Jiaotong-Liverpool University, Suzhou, China
2. State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, China
3. Department of Electronics Engineering, University of York, York, U.K.
4. School of Rail Transportation, Soochow University, Suzhou, China