Efficient Far-Field Radio Frequency Energy Harvesting for Passively Powered Sensor Networks

TLDR

The study designs an RF‑DC power conversion system to efficiently harvest far‑field RF energy into DC voltages at very low received power and voltage levels. The system uses passive rectifier circuits fabricated in 0.25 µm CMOS with floating‑gate transistor diodes, optimized for far‑field operation and capable of functioning at 44 m from a 4 W EIRP source. The 36‑stage rectifier achieves a voltage gain of 6.4, rectifying 50 mV inputs with as little as 5.5 µW received power, and its high‑voltage output at low load current makes it suitable for passively powered sensor networks.

Abstract

An RF-DC power conversion system is designed to efficiently convert far-field RF energy to DC voltages at very low received power and voltages. Passive rectifier circuits are designed in a 0.25 mum CMOS technology using floating gate transistors as rectifying diodes. The 36-stage rectifier can rectify input voltages as low as 50 mV with a voltage gain of 6.4 and operates with received power as low as 5.5 muW(22.6 dBm). Optimized for far field, the circuit operates at a distance of 44 m from a 4 W EIRP source. The high voltage range achieved at low load current make it ideal for use in passively powered sensor networks.