Synthesis of Nonuniformly Spaced Antenna Arrays Yielding Approximately Equal Sidelobes

Abstract

Based on a method briefly discussed before for nonuniformly spaced symmetric antenna arrays new conclusions arising from numerical results are presented here. The results are obtained by applying Haar's theorem. where the "minimax" error criterion rather ihan the ordinary least‐mean‐square criterion 1s used. With respect to set of element spacings, the solution obtained has the following properties: (1) the maximum deviation between the synthesized and desired patterns is minimized (2) the sidelobes are approximately equal and their level can be made minimum for a specified beamwidth, (3) both the sidelobe level and the beamwidth can be improved simultaneously by adjusting each excitation and the positions of inner pairs of elements, and therefore a better performance than the Dolph‐Chebyshev array for the same number of elements and an equal overall array length is possible, (4) a minimum number of elements required to yield a pattern of approximately equal sidelobes can be determined, and (5) the solution can be unique. The method is valid for arrays consisting of either isotropic sources or directional elements.