CPW-Fed Bow-Tie Antenna for Ambient RF Energy Harvesting Applications

This paper presents a high-efficiency bow-tie antenna for ambient RF energy harvesting at the 2.4 GHz band. Moreover, a rectifier circuit that converts the AC into DC is proposed. The antenna is fed via a CPW transmission line where a quarter wavelength transformer is inserted to match the slot bow-tie with the 50-ohm transmission line. The structure is simulated using CST software, and results are validated using HFSS. The antenna's directivity, efficiency, and bandwidth are 6.63 dBi, 89.9 %, and 0.946 GHz respectively, as simulated using CST. The antenna is fabricated on a single-layer printed circuit board, and the reflection coefficient of the antenna is measured, demonstrating excellent agreement with simulations. Through meticulous impedance matching with the rectifying circuit, the RF energy harvesting system does not require a matching impedance network.