Synthesis of sparse concentric ring arrays based on Bessel function

Abstract

In this study, a novel strategy is proposed for synthesis of sparse concentric ring arrays composed of uniformly excited elements. The synthesis problem herein is aimed at determining the sparse ring radii and the corresponding number of elements equally spaced on each ring simultaneously in order to produce circularly symmetric patterns. By using the proposed method, the above synthesis problem can be simply transformed to a single-type-variable optimisation problem since the relationship between the sparse ring radius and the element number is derived according to the properties of Bessel function. The proposed method is very efficient and flexible for synthesising direct radiating arrays and/or the scanned ones. Numerical experiments are conducted to validate the effectiveness of the proposed method. Compared with other methods, the proposed method can obtain circularly symmetric patterns using fewer elements. On this basis, the comparison of sparse array and thinning array is given through numerical experiment. Meanwhile, a scanned sparse array of 908 elements is synthesised in a circular aperture of 25λ diameter with invariant peak sidelobe level of −28.9 dB, which can steer the beam from 0° to 30° in elevation and from 0° to 360° in azimuth.