A novel semi elliptical slotted dual port rectenna for RF energy harvesting

In this paper, a novel semi elliptical slotted dual-port microstrip rectenna for harvesting ambient radio frequency (RF) energy is presented. This green energy harvesting technique captures the RF radiation with the help of an antenna and converts it to direct current (DC) power with the help of a rectifier to activate electronic devices. The presented antenna in this paper is characterized by semi elliptical shaped slots and features two ports 1 and 2. In Port 1, the antenna is designed to harvest energy from 1.71 GHz, 2.33 GHz, 5 GHz, and 5.8 GHz, while in Port 2, it is designed to harvest energy from 2.31 GHz, 3.26 GHz, and 3.84 GHz. The antenna's dimensions are 44 × 44 (mm) which is designed and simulated in HFSS Software. Aside from the antenna, a non-uniform transmission line matching circuit and a voltage doubler rectifying circuit are developed in ADS software for converting the RF power acquired by the antenna into DC power. Furthermore, the proposed antenna is fabricated and measured with a Keysight Vector Network Analyzer. The rectifying circuit is also fabricated which measures 25 × 17 (mm). At both Port 1 and 2, antenna simulation results of return loss, current distribution, radiation pattern in E-plane and H-plane, and VSWR are obtained. The antenna's simulated and measured results are observed to agree with each other. Moreover, with an input power of 10 dBm, the maximum efficiency is found to be 52%, and the output voltage is 3.2 V. The novelty of this paper lies in the fact that inserting semi elliptical slots on the four sides of the antenna’s patch creates multiple resonance frequencies and also reduces the size. Ultimately, the proposed rectenna system is compact with good efficiency, output voltage and a potential alternative source for powering low-power devices.