Reducing the Divergence of Vortex Waves with a Lens Tailored to the Utilized Circular Antenna Array

Abstract

In this paper, we propose a tailored lens in order to overcome the obstacle of the large beam divergence inherent to vortex waves that are generated by a Uniform Circular Patch Antenna Array (UCA) at 10 GHz. We implemented two lenses. The first one is a combination of 8 identical lenses, and will be called sectorized lens, where each of the sectors conforms to an underlying patch antenna element. The second lens is a smoothed version of the former one, which will be called the rotationally symmetric lens. The simulation results of the two tailored lenses are in agreement with the design expectations and show a rotationally symmetry, which is essential for an unperturbed vortex beam emission. The performance of these two designs will be compared to the patch antenna array without lens and to an ordinary extended elliptical lens. Both designed lenses have a gain of about 15.3 dBi, which is about 5.5 dBi higher than the gain of the bare patch antenna array.