Reduction of the grating lobes in Luneburg lens arrays

The reduction of the grating lobe in threeand four-element Luneburg lens arrays was studied as a function of the element spacing. The arrays were designed to have the same aperture efficiency and their computed radiation patterns are presented. For both arrays, removing part of the outer shells reduces the array spacing and improves the first grating lobe level at the expense of a small reduction of the gain. Comparing the threeand four-element LLA, the fourelement array has lower profile, lower first side lobe and first grating lobe levels, while the width of the array is increased.