Broadband Array Antenna Sidelobe Level Optimization Algorithm

In antenna synthesis, the patterns of elements in array are different from the isolated element because of mutual coupling. The traditional methods which suppose all elements patterns the same, can not satisfy the actual applications without considering the mutual coupling. So, a common method which can solve the mutual coupling of arrays is needed in application due to the uncertainty of mutual coupling.Aiming at the problems above, this paper works on the research of practical array-pattern synthesis making use of genetic algorithm(GA) and eigen-driven analysis method, because of the excellent characteristics of GA, such as solving multiple complex problems with large space, non-linear, whole optimization searching and so on which the traditional methods don not have.Firstly, the development of low Sidelobe Level(SLL) pattern synthesis and the application of GA in pattern synthesis are introduced. The disadvantages of traditional approaches for solving the mutual coupling in pattern synthesis are presented. Subsequently, the concepts and characteristics of GA are studied. And an eigen-driven analysis method uniting GA used in this paper for considering mutual coupling is proposed.Secondly, the improvement for traditional real coding GA is studied deeply. A disruption-based tournament selection, a multiple hybrid crossover operator and a self-supervised mutation process are developed to improve the convergence performance. The selection of simulated annealing is used to accelerate the convergence of GA. The results from simulation illustrate that with the improved algorithm, the SLL has been successfully lowered, comparing to Chebyshev theory array and the recently reported paper.At last, an 8-12GHz wideband Vivaldi taper slot antenna has been designed. The influences of mutual coupling to standing wave and unit pattern are discussed. And the proposed approach is used to optimize the SLL of Vivaldi linear and planar arrays. Compared with conventional methods, the approach proposed can get lower SLL with the same wide of main lobe, effectively solving the mutual coupling of arrays.