Dual Band Circularly Polarized Proximity Coupled Stacked Patch Antenna for RF Energy Harvesting

Abstract

Antennas have a wide range of applications in different fields. Some of the antennas are designed for airborne communications while some antennas have vehicular, signal intelligence and ISR (intelligence, surveillance and reconnaissance) applications. Certain antennas are designed for specific applications, which are suitable for particular purpose, but a number of antennas are multi performing and are versatile. These antennas have a number of feeding techniques. For instance microstrip line feeding, microstrip inset line feeding, coaxial line feeding, aperture coupled feeding and proximity coupled feeding line. In this research project, proximity coupled feeding technique is applied. A circularly polarized stacked dual band microstrip patch antenna is designed with a cavity backed feeding substrate. In order to get the resonances, the width and length of upper and lower patch is varied. In addition, two stacked patches provide good impedance matching. The feeding line and cavity in the ground plays a pivotal role in getting the required resonances of interest at the desired bands of frequency. The measured results of the fabricated prototype comply with the simulated results. The dual band stacked patch antenna gives 5.19dBi and 5.59dBi gain at 1.75 GHz and 2.38 GHz respectively. The antenna efficiency is 90% and 75% at both these bands with stable radiation patterns.