Thinning planar array antennas with ring arrays

A study has been made of thinning planar arrays by removing a large fraction of the elements, but keeping the main lobe width relatively unchanged and maintaining reasonably good sidelobe levels. The amplitude of the signal at each element is assumed constant (no amplitude taper). Peak sidelobes of the order of -25 db are obtained with a 10,000 element array thinned 90 percent (1000 elements remaining). Several approaches have been taken in designing the element configuration to achieve these sidelobes, but all use concentric ring arrays where the elements are placed at the intersection of rings with radials. The behavior of the pattern when the beam is steered off broadside has also been investigated and a slight deterioration of peak sidelobes has been noted.