Single layer metasurface lens antenna

This paper shows how a set of metallic rings can be used as a planar lens to increase the directivity of a single open waveguide. The goal of this antenna is to obtain a high gain over a wide bandwidth, while maintaining a compact size. In order to obtain a physical insight of the radiating behavior, an analysis of the characteristic modes in the metallic ring of the elementary antenna is performed. An efficient optimization process has been carried out in order to find out the optimum dimensions of the antenna. This study is used to improve the return loss level of a single-layer lens, formed by a central metallic ring surrounded by eight small rings, over a resonant ground circular aperture antenna from 3 to 7 GHz and from 10 to 14 GHz.