A Broadband High-Efficiency Rectifier for Mid-Field Wireless Power Transfer

In this letter, a compact broadband high-efficiency microwave rectifier is presented for powering implantable medical devices located deeply in the human body. By utilizing a modified real frequency technique and an RF step-up transformer at the input matching network, the proposed rectifier has a measured conversion efficiency ( η) exceeding 50% over a 62% fractional bandwidth from 900 to 1700 MHz at 0-dBm input power level. For measured η above 50%, the widest dynamic input power range achieved is from -7 to 14.2 dBm at 1.5 GHz, and the circuit sensitivity reaches up to -20 dBm with at least 8% conversion efficiency. The circuit has a compact size of 16×11 mm
²
, being suitable for biomedical implant applications.