Paper Title
A Novel Luneburg Lens Antenna Design based on Meta-Materials with Secondary Concentrating Lens

Abstract
Luneburg lens is a new generation of antennas that is developed in the last few years and inserts itself strongly in Microwaves, Communications and Telescopes area. The aim of this paper is to improve the radiation pattern by decreasing the side lobes and increasing the main lobe while realizing wide-angle beam scanning when the source moves along the circumferential direction inside the lens. The design and characterization of a modified two-dimensional Luneburg lens based on meta-materials along with the analysis and simulation results are presented. The lens is composed by a number of concentric layers. By varying the geometric dimensions of unit cells in each layer, the gradient refractive index profile required for the modified Luneburg lens can be achieved. The cylindrical waves generated from a point source at the focus point of the lens could be transformed into plane waves as desired in the microwave frequency. Keywords - Luneburg Lens Antenna, Met-materials, Beam Scanning, Gradient Refractive Index.