Reduction of phase shifting for range expansion in magnetic resonance coupling-based distance sensor with adjustable sensing range

The realization of wireless charging and self-localization as an integrated compact system using magnetic resonance coupling is useful as an application for mobile robots. However, the narrow sensing range, due to the fact that the sensing method is categorized as passive sensing, was a problem in the practical use. Thus, the method which enables control of the sensing range by virtually adjusting the quality factor of the antenna is proposed as a solution. However, the phase shifting error made it difficult to maintain the resonance status in case of high-Q. Thus, this paper introduced the redesigned configuration of the quality factor control circuit. The configuration enabled the dramatical increase of Q up to 30 times the original value, which is expected to extend the sensing range to two times and reduce the number of arrayed transmitter antenna to one fourth.