Efficiency-Enhanced Wireless Power Transfer Based on Multiple Coupling Paths

This letter presents a novel efficiency-enhanced wireless power transfer (WPT) system operating at 13.56-MHz ISM band. Dual sub-resonators at both transmitting and receiving ends are employed to introduce multiple coupling paths and boost system efficiency. The closed-form equations are derived to verify the advantages of the proposed scheme. A prototype of the WPT system is implemented using the printed circuit board (PCB) technique, which features easy fabrication and small volume. The dual sub-resonators are fabricated on both sides of the PCB with a total dimension of 15 ×15 cm2. Experimental and simulated results which exhibit a good agreement are presented and discussed. An efficiency of 90% is achieved at 15 cm, implying an enhancement of approximately 7% as compared with the conventional WPT schemes.