Wireless power transmission system for transmitting alternating-current power wirelessly

A wireless power transmission system transmitting alternating-current power from a power transmission device to a power reception device, wherein

• the power transmission device comprises:
• a first and a second electrode which are disposed across a predetermined distance, in which a total width including the predetermined distance is λ/2π or less as a near field, the first and the second electrode each having a rotationally symmetrical shape with respect to a common center axis;
• a first and a second connection line electrically connecting the first and the second electrode and two output terminals of an alternating-current power generating unit, respectively;
• and
• a first inductor residing between the first and the second electrode and at least one of the two output terminals of the alternating current power generating unit, and
• the power reception device comprises:
• a third and a fourth electrode which are disposed across a predetermined distance, in which a total width including the predetermined distance is λ/2π or less as a near field, the third and the fourth electrode each having a rotationally symmetrical shape with respect to a common center axis;
• a third and a fourth connection line electrically connecting the third and the fourth electrode and two input terminals of a load, respectively;
• and
• a second inductor residing between the third and the fourth electrode and at least one of the two input terminals of the load, wherein:
• the electrodes of the power transmission device and the power reception device are disposed to oppose each other across a distance of λ/2π or less as a near field,
• a resonance frequency of a coupler constituted of the first and the second electrode and the first inductor and a resonance frequency of a coupler constituted of the third and the fourth electrode and the second inductor are set to be substantially equal,
• the first electrode has a first platy polygonal or circular shape, and the second electrode has a second platy polygonal or circular annular shape disposed to surround the first electrode and is disposed on a same plane to have a first center axis corresponding to that of the first electrode,
• the third electrode has a third platy polygonal or circular shape, and the fourth electrode has a fourth platy polygonal or circular annular shape disposed to surround the third electrode and is disposed on a same plane to have a second center axis corresponding to that of the third electrode, and
• the first and the second electrode and the third and the fourth electrode are disposed to oppose each other across a distance of λ/2π or less as a near field.