Patent ID: 8045947

Claim:
A far-field power extraction circuit comprising: an antenna comprising: an inductive loop; two impedance inverters each coupled to the inductive loop; and two resonant loops each coupled to a respective one of the two impedance inverters, the antenna configured to receive an electromagnetic signal, said antenna having a resonant frequency and configured to subsequently match an antenna impedance with a remainder of the far-field power extraction circuit at the resonant frequency; and a multi-stage rectifier coupled to the antenna, the multi-stage rectifier adapted to receive an electromagnetic signal from the antenna and in response thereto, to produce a direct current (DC) voltage at a rectifier output, the multi-stage rectifier comprising N stages, where N >1, wherein the multi-stage rectifier comprises at least one circuit element having a nonlinear capacitance characteristic and at least one inductor between each of the rectifier stages.