Research And Application Of Antenna Array Layout Optimization Algorithm

Modem electromagnetic theory depends on optimization techniques largely when it is applied to radiation and scattering problems.However,the objective functions of the optimization problems are mostly highly nonlinear,have many extreme values and are not guidable.Therefore,the need for intelligent,efficient optimization techniques becomes very urgent.This paper focuses on the array layout optimization in deep-space communications and electronic reconnaissance systems.In the field of deep-space communication,the demand for system receiving sensitivity has been continuously improved.Currently,large-scale small aperture(6-12m)antenna array technology is mainly adopted.By optimizing the geographical layout of array elements,the antenna array system generates low side-lobe and improves the receiving sensitivity.In the field of electronic reconnaissance,the antenna needs to have a wide frequency band,large angle scanning,high gain,and low sidelobe performance.In this way the antenna arrays with unequally spaced distributions are generally used.Therefore,how to determine the location of each unit,the amplitude and phase of the feed has a very important engineering application value.This thesis proposes a highly efficient improved genetic algorithm and an enhanced particle swarm algorithm for the above two areas.Optimized by the algorithm,the target radiation performance of the antenna array has greatly improved.The author's main work is summarized as follows.First of all,aiming at the inherent defects of the traditional genetic algorithm,this thesis proposes an improved genetic algorithm with better performance.The algorithm does not set a specific selection probability and a crossover probability.It improves the evolutionary efficiency by adding the elite retention strategy and the optimal individual reinforcement operator Secondly,an enhanced particle swarm optimization algorithm is proposed.The algorithm fully considers that the global sub-optimal particle's motion trajectory also has a great reference value.In the algorithm,a new velocity update method and a global optimal particle perturbation operator are introduced to improve the search rate of the new algorithm.Then,gradient algorithms,improved genetic algorithms and enhanced particle swarm optimization algorithms are used for the optimization of deep-space antenna array layout.The array operating in X-band and consists of different number of array elements.Through comparison,the improved genetic algorithm has better performance.For a fixed number of unit arrays,the improved genetic algorithm presented in this paper is used to divide the subarrays.And the optimal layout for engineering applications under different conditions is obtained.Finally,the improved genetic algorithm proposed in this paper is used to optimize the layout of an ultra-wideband antenna array.The array is used in the field of electronic reconnaissance.After optimization,low sidelobe and wide-angle scanning performance is achieved in the frequency range from 6GHz to 18GHz.What's more,an antenna array prototype was made according to the optimized spacing.The pattern of antenna elements in the array was tested and the array pattern was synthesized.The final algorithm optimization results,simulation results and test results are in good agreement,verifying the effectiveness of the algorithm and the correctness of the design.