Design and optimization of a radio frequency energy harvesting system for energizing low power devices

This paper proposes a radio frequency (RF) energy harvesting system which enables scavenging energy from an electromagnetic far field. The system consists of a quarter-wave monopole antenna, a matching circuit, an energy conversion module, an energy storage capacitor, a low-power comparator and a DC-to-DC converter. The RF energy harvester operates at a frequency band of 868 MHz and creates a pulsed output voltage of about 1.8 V at an input power of at least -6 dBm. The system can be used to power a wireless low-power sensor node. With this approach, a battery-less sensor network is made possible.