Equivalent circuits of repeater antennas for wireless power transfer via magnetic resonant coupling

Recently, expectations from the technology of wireless power transfer via magnetic resonant coupling have increased. Magnetic resonant coupling is a new technology that achieves power transfers across a large air gap by using transmitting and receiving antennas. However, repeater antennas enable power transmission across even larger distance. These repeater antennas without cross coupling can be expressed as a T-type equivalent circuit. The equivalent circuit including cross coupling and mutual inductance, which is related to the antenna position, has not been studied. This paper proposes a novel way to represent the repeater antenna by equivalent circuit and a way to determine the mutual inductance and verified by performing electromagnetic field analysis and an experiment.