Design and Implementation of a Wideband Rectenna for RF Energy Harvesting in Smart Agriculture

The increasing demand for autonomous agricultural monitoring systems necessitates reliable, maintenance-free power solutions for wireless sensor networks (WSNs) deployed in remote fields. Conventional energy sources, such as batteries and solar panels, are limited by replacement cycles, weather dependence, and maintenance costs. This paper presents the design, fabrication, and experimental validation of a wideband rectenna-based RF energy harvesting system operating from 1.5 GHz to 10 GHz, covering multiple communication bands including GSM, LTE, Wi-Fi, and 5G. The proposed spiral slot antenna, integrated with a ground reflector, achieves a measured directional gain of up to 9.39 dBi and maintains an S11 below 15 dB across the target frequency range. A fixed LC impedance matching network is employed to optimize power transfer to a Schottky-diode based rectifier, enabling efficient conversion of ambient RF energy into usable DC power. The fabricated system delivers a stable output voltage between 0.71 V and 1.21 V for input power levels ranging from 0 dBm to 5 dBm, which is subsequently boosted to standard sensor operating voltages using a DC–DC converter. Field measurements demonstrate successful powering of soil moisture sensors in rural agricultural environments, confirming the system’s cost-effectiveness, scalability, and suitability for precision farming applications.