Q Controllable Antenna as a Potential Means for Wide-Area Sensing and Communication in Wireless Charging via Coupled Magnetic Resonances

Recently, wireless charging via coupled magnetic resonances gains attention because it has a potential of efficient mid-range wireless charging. Here, functions such as sensing at the transmitter and wireless communication from the target are the essential elements to realize the standard wireless charging system. Currently, the sensing and communication protocol of hardware (i.e., high-frequency power source and antenna configuration) compatible with wireless charging is gaining attention in terms of cost and space reduction due to the use of common components in multiple functions. However, these protocols have the problem of narrow effective areas. Therefore, this paper presents a method for wide-area sensing and communication with slight modification of the configuration. The basic concept is to expand the effective area related to antenna Q factor by using the Q controllable antenna acting as though the Q factor increased. The underlying theory was described with electric circuit theory. The experimental results showed that the Q factor can be increased until the resonance collapses, and the increase of Q factor has the potential to widen the effective area of sensing and communication.