Analysis and design of high efficiency inductive power-links using a novel matching strategy

One of the major factors that limit the powering distance in any RF energy scavenging sensor is the intrinsic threshold of the voltage-multiplier or voltage-boosting circuits. In this paper we present a passive matching network that overcomes the threshold-voltage limitation by enhancing the quality-factor of the voltage-multiplier front-end. We first derive the figures-of-merits comparing the theoretical improvements that can be achieved by the proposed matching network over a conventional parallel matching network. Using measured results from prototypes fabricated in a 0.5-μm CMOS process we show that for a fixed transmission power, the proposed approach significantly increases the powering distance of a 13.56MHz RF scavenging sensor.