The Study Of Pattern Synthesis Based On Genetic Algorithm And Nulls Steering For Antenna Array

The applications of antenna arrays can be found in many areas such as radar, sonar, wireless communications and electronic warfare. As the key technologies in antenna array, pattern synthesis has been widely used in interference suppression, probability of intercept and parameter estimation. The optimization of pattern function is non-linear problem. In resent years, as its global search performance and having no restraint of differentiable and continuities, genetic algorithm has been widely used in pattern synthesis of antenna array. However, premature convergences always exist in genetic algorithm for its oneness and exclusiveness. Niche genetic algorithm (NicheGA) hasn't the weaknesses of premature convergence and local searing which exist in the simple genetic algorithm (SGA), and it can keep the population diversity well.In this paper, some algorithms which are applied in linear antenna array pattern synthesis are considered. In addition, the paper takes mutual coupling between elements and its compensation into account.First of all, niche genetic algorithm is applied in linear antenna array pattern synthesis to receive low sidelobe level and nulls with given depth in some given directions. At the same time, the convergence of the algorithm is also observed. The results of emulation indicate that niche genetic algorithm is good for linear antenna array pattern synthesis and its convergence rate is better.Secondly, amplitude perturbations based on niche genetic algorithm is used to forming nulls. This method doesn't need formula derivation, and it has good convergence and stability. After the narrow nulls steering, two methods for broad nulls steering are considered, grounded on the theory of derivative constraints. The two methods can keep level of null center very deep.The last, the effect of mutual coupling on pattern synthesis has been analyzed by Method of Moment based on the above analyses. The results show that the effects of mutual coupling make sidelibe level higher, the nulls excursive or narrow. In addition, three methods for compensating of mutual coupling effects are introduced, and the results of emulation are compared, too.