Dual-Polarised Broadband Antenna for RF Energy Harvesting in 5G Applications

The rapid global deployment of 5G communication networks is driven by rising population density, the surge in IoT device adoption, and the bandwidth constraints of existing 4G infrastructure. As a result, the surrounding electromagnetic environment is becoming increasingly saturated with RF signals, particularly within the sub-6 GHz spectrum utilised by 5G systems. This creates an opportunity to harvest ambient RF energy to power low-power electronic devices. In this work, we propose a compact, broadband energy harvesting system consisting of a wideband antipodal slot antenna and a high-efficiency broadband rectifier. The proposed system is designed to operate across the 5G N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), & N79 (4.4-5.0 GHz) dual wideband frequencies. The rectifier, based on the HSMS-2860 Schottky diode, achieves conversion efficiencies of up to 68%, 62%, and 61% at 3.4 GHz, 4.1 GHz, and 4.8 GHz, respectively, under input power levels of 15 dBm, 11 dBm, and 10 dBm with a 900 Ωload. The antenna, designed on an FR4 substrate, exhibits a wide operating bandwidth of 2.8-5.8 GHz, effectively covering key 5G and WLAN bands. The primary contributions of this research to the state of the art in industrial sub-6 GHz RFEH systems are as follows: The proposed rectenna system demonstrates high performance and holds strong potential for powering IoT devices and wireless sensor nodes in 5G-enabled environments.