Design of overlapped sub-arrays for planar sparse direct radiating arrays

In the current work we focus on sparse array design employing overlapping radiating elements. In this case, the underlying sparse grid shapes the broadside directivity far-field pattern while the overlapping flat-top producing sub-arrays eliminate the scanning loses. In detail, when overlapping arrays are involved the design process is as follows: Perform broadside design, (not scanning beam), using elements' size that keeps Grating Lobes just out of the Field of View (FoV). Since we use Flat-top elements their directivity is reduced and thus their number and/or their size should be increased to balance the two directivity trends. If the element number increase in the previous step is lower than the respective element number increase due to scanning losses when employing non-overlapping arrays, (and non-Flat-topped element), then we have an accepted solution; In most of the cases, this means that using overlapping we achieve a remarkable reduction in the number of control points.