A Dual-Band Dual-Polarized Rectenna for Efficient RF Energy Harvesting in Battery-Less IoT Devices With Broad Power Range

Abstract

The demand for maintenance-free, battery-less IoT devices, driven by sustainable Industry 4.0 practices, necessitates efficient RF energy harvesting solutions. Addressing the limitations of single-frequency harvesting, a novel dual-band, dual-polarized rectenna operating at 3.6 GHz and 5.8 GHz is proposed. The antenna resonates at 3.6 GHz with linearly polarized (LP) characteristics and 5.8 GHz with circularly polarized (CP) characteristics with impedance bandwidth (IBW) of 2.2% and 5.63%, respectively, achieving a gain of 4.85 dBi and 6.75 dBic, respectively. A rectenna consists of an antenna at the front end and an RF-DC rectifier at the backend. This approach maximizes power conversion efficiency by minimizing impedance mismatches and reflection losses and mitigates interference between the dual bands within the rectifier circuitry. The rectifier achieves peak efficiencies of 65.5% at 3.6 GHz with a 3 dBm input and 44% at 5.8 GHz with a −1 dBm input, both with 2KΩ load. Efficiency exceeds 30% at 3.6 GHz for an input range from −10 to 6.5 dBm and exceeds 20% at 5.8 GHz for an input range from −13 to 3 dBm. These design considerations enable reliable harvesting of ambient RF energy across a range of −20 to 20 dBm, enabling continuous IoT device operation. Our measurements confirm the design's effectiveness in converting low-power RF signals into usable energy, supporting sustainable and autonomous IoT deployments at 3.6 and 5.8 GHz.