Efficient Dual Band RF Energy Harvesting Front End for Ultra Low Power Sensitive Passive Wearable Devices

This paper demonstrates a double-band RF energy harvesting system, to be used with a passive wearable device operating at a distance of 6-20 m from a wireless power source. The double-band RF energy harvesting circuit that is presented in this paper, can harvest an input power as low as -14 dBm from both 925 MHz and 2.4 GHz, ISM frequencies. The harvesting circuit is implemented in a standard 0.18 μm CMOS technology and gives a regulated output voltage of 1.1 V. Post-layout simulations show an overall system efficiency of 41.87% and 46.95% at 953 MHz and 2.4 GHz respectively, while driving a load resistance of 60 kΩ.