Electric power transmission device and electric power transmission method

An electric power transmission device which wirelessly transmits an electric power in a conducting medium characterized in that

• the electric power transmission device includes a power transmitting unit which wirelessly transmits an electric power and a power receiving unit which receives the electric power transmitted from the power transmitting unit,
• the power transmitting unit and the power receiving unit include an inclusion unit which includes a coil for electric power transmission and a dielectric material covering the coil for electric power transmission,
• at least one of the power transmitting unit and the power receiving unit includes an impedance adjustment unit which varies the impedance thereof, and
• the electric power is transmitted at a resonance frequency determined by an impedance of the power transmitting unit, an impedance of the power receiving unit, and an impedance of the conducting medium,
• wherein a relation of 30>C3*d/(C1+C2)>0.5 is satisfied wherein C1 is a capacitive component (C1 [pF]) of which the impedance of the power transmitting unit is composed, C2 is a capacitive component (C2 [pF]) of which the impedance of the power receiving unit is composed, C3 is a capacitive component (C3 [pF]) formed by the power transmitting unit, the power receiving unit, and the conducting medium, and d is a distance (d [cm]) between the power transmitting unit and the power receiving unit.