School of Electrical Engineering and Automation Tianjin Polytechnic University Tianjin 300387 China;
School of Electrical Engineering and Automation Tianjin Polytechnic University Tianjin 300387 China;
College of Electrical Engineering and New Energy China Three Gorges University Yichang 443002 China;
School of Electrical Engineering and Automation Tianjin Polytechnic University Tianjin 300387 China;
Wireless power transfer; frequency splitting; weak-coupling region; coil design;