Radio frequency energy harvesting from ambient FM signals for making battery-less sensor nodes for wireless sensor networks

This paper presents an efficient rectifier for Radio Frequency (RF) energy harvesting applications in FM band (88MHz to 108MHz). The proposed rectifier is based on Modified Greinacher Rectification topology. The circuit is designed on Keysight Advance Design System (ADS) and realized on a 1.6mm thick FR4 sheet with 35um of copper cladding. Schottky diode, HSMS2850 is used as rectification element and lumped components are used for impedance matching. Power levels of interest are from −30dBm to 0dBm. The rectifier operates optimally for a load range of 10kΩ to 75kΩ with maximum RF to DC conversion efficiency of 74.8% for 5dBm input power at 96 MHz. The conversion efficiency for entire FM band for −10 dBm input is around 50% which is the typical input power level of ambient wireless signals. Measurements show excellent agreement with the simulated results. The proposed rectifier has harvested 12.77 μW of DC power from an input of −14.2dBm channel power with an overall efficiency of 33.59% in FM band.