Reduction of near-field grating lobes in sparse linear phased arrays

We provide performance information on the reduction of sidelobe levels in sparse linear phased arrays operating in the near-field. Iterative optimization techniques are used to choose inter-element spacings which reduce grating lobe magnitudes at select distances, and array configurations are generated with constraints on the minimum spacing between elements. The performance of these array configurations is then analyzed over a scan angle of 180 degrees. We show that it is possible to generate arrays which outperform the side-lobe level of far-field-optimized array configurations in the near-field by as much as 3 dB.