Synthesis of Thinned Planar Circular and Square Arrays Using Density Tapering

Two new hybrid density taper methods for designing thinned planar arrays are presented. Both methods make use of a model taper to allocate for a number of rings across the array aperture the amount of turned ON elements per ring. One method applies a modified version of the iterative Fourier transform (IFT) method to find the optimum turned ON element distribution for each ring to get a prescribed low sidelobe level. The second method gets suitable turned ON element locations by distributing these elements in a uniform random way over each ring. The purpose of the second method is to find the optimum model taper since it is computational faster than the first method. Using the model taper determined by the second method, the first method finds then the optimum locations of the turned ON element positions. Both new methods can deal with the synthesis of thinned planar arrays of any size, any aperture shape and any degree of thinning. A wide range of numerical examples covering very small up to extremely large arrays will demonstrate the effectiveness of the two proposed methods for both circular and square aperture shapes.