Pattern Synthesis Of Conformal Array Based On Improved Multi-Objective Intelligent Optimization Algorithm

Conformal array antenna is an antenna which is designed to conform some prescribed shape.The conformal array not only has good appearance,but also enhances the aerodynamic performance of the carrier,improves the antenna diameter,increases the scanning range of the antenna and so on.Therefore,the conformal array antenna has been widely applied in the fields of radar detection,satellite communications and so on.The pattern synthesis of conformal array is a typical optimization problem,which often contains multiple optimization objectives,such as the main lobe shape,side-lobe level,null steering,array efficiency and polarization direction.Because these optimization goals are often mutually exclusive,the coplanar pattern synthesis problem becomes a multi-objective optimization problem.In view of this,this thesis proposes multi-objective intelligent optimization algorithms to solve the problem of conformal pattern synthesis.The main contents of this thesis are as follows:Firstly,a basic signal model of the conformal array is established,and a far-field pattern function is given.Several common methods of the conformal pattern are introduced and simulated.Secondly,the basic idea and the steps of the multi-objective optimization algorithm are introduced.The multi-objective artificial bee colony algorithm(MOABC)based on Pareto Optimality is introduced.In this thesis,the neighborhood search strategy,the crowding distance,the selection algorithm and the search step are improved for the characteristics of the conformal array pattern synthesis problem.The improved algorithm is called improved multi-objective artificial bee colony algorithm(IMOABC).Finally,two typical multi-objective pattern synthesis problems are analyzed by using IMOABC algorithm.The first is to maximize the array efficiency of the conformal array pattern synthesis.The optimization objective are the pattern of waveform and the relatively array efficiency.As the array efficiency is affected by the shape of the conformal array,this thesis defines the relative array efficiency as the object of comparison.Then,the pattern of the conformal array of dual-polarized antenna is synthesized and the objectives are the two different polarization patterns.The difficulty is that the direction of each antenna element is different,so the corresponding polarization direction is also different.This problem is solved by the rotation of the coordinate axis.After that,the optimization of the co-polarization pattern and the suppression of the orthogonal polarization pattern are realized at the same time.