Employing the aperture orthogonal polynomials method in the design of sparse unequally spaced phased arrays

A new method is considered for designing the linear and planar unequally spaced phased arrays (USPAs) in which the number of elements may be practically unlimited. This method is based on aperture orthogonal polynomials and enables one to find the law by which elements are positioned in the array aperture so as to eliminate parasite sidelobes similar to diffraction lobes in the scanning sector or over a wide operating frequency band. A sparse USPA is shown to have an increase in the level of side lobe radiation and a decrease in the array gain, while the array resolution remains unaltered. The behavior of USPA directivity is numerically estimated and the dependence of the degree of USPA directivity reduction on the average distance between elements is presented.