Patent ID: 8508076

Claim:
A wireless power transmission unit comprising: an oscillator for converting DC energy into RF energy having a frequency f 0 ; a first antenna for transmitting the RF energy, the first antenna including a first inductor and a first capacitor that are connected together in series to form a series resonant circuit with a resonant frequency fT; and a second antenna for receiving, by resonant magnetic coupling, at least a part of the RF energy that has been transmitted by the first antenna, the second antenna including a second inductor and a second capacitor that are connected in parallel with each other to form a parallel resonant circuit with a resonant frequency fR, wherein the resonant frequencies fT and fR are set to be substantially equal to the frequency f 0 of the RF energy, the oscillator has a voltage step-up ratio Voc, the first inductor has an inductance L 1 , the second inductor has an inductance L 2 , the second inductor is coupled with the first inductor by a resonant magnetic field at a coupling coefficient k which is set to be less than 0.5, and the power transmission unit satisfies (L 2 /L 1 )≧4(k/Voc) 2 .