The use of multi-resonators for medium-range wireless power transfer (WPT) systems is an important concern; the cross-couplings between non-adjacent coils have an adversely impact on the transmission distance and efficiency of the system. This paper proposes a dumbbell-shaped (DS) coil in a WPT system. The DS coil structure was analyzed theoretically and verified experimentally. The proposed scheme eliminates cross-couplings between non-adjacent coils in the multiple resonator system to resolve frequency drift, and improve the transmission distance and efficiency in the multiple resonator system. The scheme features a coplanar structure which can secure direct-coupling and save space when applied in the home, office, and public areas.
2017 by The Institute of Electronics, Information and Communication Engineers