High-efficiency triple-band ambient RF energy harvesting for wireless body sensor network

This paper proposes a triple-band rectifying circuit for ambient RF energy harvesting, which can be served as a power supply for the central unit in Wireless Body Sensor Networks (WBSN). It fully utilizes the RF energy in ambient and converts it into DC power with high efficiency. It covers the public telecommunication bands of GSM-900, GSM-1800 and UTMS-2100, which are measured to hold the major RF energy in ambient. Simultaneous multiband energy collection helps in achieving high conversion efficiency, which is around twice that of the conventional separate single-band inputs. Measurement results show that 31.2% RF-to-DC conversion efficiency and 159mV output DC voltage are gained over a resistive load of 3.3 KΩ with an input RF power of -20dBm.