Sidelobe reduction through subarray overlapping for wideband arrays

For wideband arrays, the contiguous subarray architecture using phase shifters at the element level and true time delays at the subarray level results in higher sidelobes due to subarray dispersion and grating-lobe generation. Sidelobe reduction using overlapping subarray architecture is discussed. The architecture is effectively applied to an experimental AMRF-C (Advanced Multifunction RF Concept program) receive system. It is shown that, in addition to aperture weight distribution at different stages, the overlap ratio between subarray aperture size and subarray step size primarily affects the array sidelobe performance. Excellent sidelobe performance is achieved over large bandwidth when the overlap ratio is close to 2 and typical Taylor weight distributions are used at both element and subarray levels.