Integrated Dual-Mode Energy Harvesting for Self-Sustaining Sensor Nodes: Synergy of Solar and RF Energies

The proliferation of wireless sensor networks (WSNs) in the Internet of Things (IoT) applications has necessitated the development of sustainable energy solutions to ensure longevity and reduce maintenance costs. In this regard, this paper presents a novel battery-less sensor node, referred to as the Integrated Dual-Mode Backscattering Energy Harvester (IDM-BEH), that harnesses energy from both light and radio frequency (RF) sources, thereby enabling operation without the need for a battery. This node incorporates a synergistic antenna-solar array integration coupled with a dual-band (2.4-2.6 GHz and 3.45-3.55 GHz) rectifier and backscattering module for RF energy harvesting and uplink communication, respectively. The IDM-BEH achieved 25.76 % peak energy harvesting efficiency and 9.8 dB backscattering dynamic range in the measurements. The circuit was able to harvest 17.4 μW of power at a 1.2 m distance from the RF source and a light intensity of 186.6 lx.