3-D free-access WPT system for charging movable terminals

There are strong demands for providing small power to movable handy terminals by a resonance-type wireless power transfer system. Continuous charging for cellular phones in a room is the best example. Conventional WPT system has a limited capability to transfer power for the movable terminals with arbitrary positions and angles. We do not enjoy the merits of the wireless system. In this paper, a novel WPT system, which uses larger transmitting resonators embedded in a floor and in walls and a smaller receiving resonator installed in a handy terminal, is proposed. The larger transmitting resonator can transfer power for full space in the room, and the smaller receiving resonator is suitable for compact terminals. We evaluate the transmission efficiency in terms of coupling coefficient for any positions and any angles of the movable terminal in a room. To realize 3-D free-access, multiple transmission resonators are employed. The coupling coefficients are measured experimentally. Then, the possibility is confirmed.