Mid-range Wireless Power Transmission in Space

Wireless power transmission using magnetic resonance is discussed. Theoretical transmission efficiency was derived as a function of impedance ratio r and RF frequency ω. Impedance matching is possible to attain maximum transmission efficiency for various coupling coefficient cases. Power feeding demonstration to an electric powered helicopter was conducted to develop an efficient, compact, and light-weight resonator as a receiver and to show the validity of the theoretical prediction. In this system, dielectric loss of the capacitor was found predominant and is liming the quality factor Q of the resonator.