A Genetic Algorithm Optimization Procedure for the Design of Uniformly Excited and Nonuniformly Spaced Broadband Low Sidelobe Arrays

Abstract

This paper presents a systematic methodology for designing uniformly excited broadband low sidelobe linear and planar antenna arrays by varying interelement spacings. In the past, attempts to develop a robust array broadbanding design technique have been only marginally successful because of the large number of possible spacing combinations involved, coupled with the theoretical limitations surrounding the problem. The genetic algorithm (GA) has recently proven to be a very effective design tool for nonuniformly spaced low sidelobe antenna arrays with uniform excitation intended for operation at a single frequency. This paper introduces an approach for extending previous applications of GA to include the design of optimal low sidelobe arrays that operable over a band of frequencies. In addition, it will be demonstrated that designing for low sidelobe operation over a bandwidth adds significant array steerability that can be described as a simple mathematical relation. Finally, it will be shown that the GA objective function is no more complicated to evaluate for broadbanding purposes than it is in the single frequency case. Several examples of GA-designed broadband low sidelobe arrays will be presented and discussed.