Passive 5.8GHz RF Energy Harvester in 65nm CMOS

This paper presents a passive 5.8GHz RF Energy Harvester (RFEH) implemented in 65nm CMOS technology that allows batteryless operation and reduction in overall size of WSN and IoT sensor nodes, which are limiting more widespread implementation. The RFEH consists of an on-chip matching network and optimized rectifier that are co-designed for maximum efficiency and sensitivity in the RFEH in gathering the required energy for the load circuit. The passive 5.8GHz RFEH prototype demonstrated a sensitivity of around -13dBm in gathering enough energy to produce 0.5V on a 10uF capacitive load, allowing the harvested energy to be reasonably combined with energy from other sources. When used as the only energy source, the ability to gather and provide a continuous supply of 8uW (10uA at 0.8V) is demonstrated, which is enough to power low-power RF circuits such as OOK and FSK receivers without the need of any battery, allowing batteryless operation.