US Patent 8045947 RF power extracting circuit and related techniques

In one aspect, the invention is a far-field power extraction circuit which includes an integrated antenna and impedance matching portion and a rectifier portion. The antenna and impedance matching portion includes an antenna configured to be responsive to a propagating electromagnetic signal and which provides a resonant response at a resonant frequency. In response to the electromagnetic signal, the antenna provides an electromagnetic output signal at an antenna port. The antenna and impedance matching portion is configured to match an antenna impedance with a remainder of the far-field power extraction circuit including the rectifier portion of the power extraction circuit coupled to the antenna and impedance matching portion. The rectifier is configured to rectify the electromagnetic output signal provided by the antenna to produce a direct current (DC) voltage at an output of the rectifier.