Harvesting Ultra-Low Power Wireless Signals in the GHz Range

Abstract

We present methods for harvesting wireless energy as low as -30 dBm (1uW) from the 2.4 GHz frequency range (e.g. WiFi signals) with discrete components. We have constructed a proof-of-concept device which is capable of operating at -18.8 dBm (13.2 uW) with no onboard power sources, relying solely on the 2.4 GHz energy source. The device is constructed on a PCB and consists of an impedance matching network, a rectifier, and a DC-DC converter. The impedance matching network matches a 2.4 GHz 50 Ohm input source to the high impedance rectifier and provides a passive boost. The rectifier converts the AC signal from the impedance matching network to a DC signal. This DC signal feeds into the DC-DC converter subsystem which boosts the voltage from about 45 mV DC to a clean 95 mV DC output.