Focusing performance of Luneburg lenses based on a broadband artificial dielectric metamaterial

In this work we present the results of numerical investigation of the microwave Luneburg lenses based on a broadband metamaterial composed of radially diverging dielectric rods. The gradual Luneburg's permittivity profile is achieved in these lenses through arranging identical dielectrical thin rods with a spatially variable cross-section in various radial directions with a subwavelength separation. The influence of anisotropy effects on the lens's focussing performance is discussed. The results reveal that, although anisotropy of the structure of diverging rods causes aperture phase errors under certain feeding conditions it may operate as a Luneburg lens.