Optimal Design Of 0.9-6GHz Multilayer Electromagnetic Radiation Suppression Composites

Microwave absorbing materials can effectively suppress electromagnetic radiation and are used in many scenes of military and daily life.However,with the development of electromagnetic wave application technology and the increase of microwave absorbing function requirements,the traditional single microwave absorbing material has been difficult to meet various complex application requirements.Multi-layer absorbing materials can adjust the overall performance of multi-layer materials to meet a variety of complex functional requirements by adjusting the type and thickness of each layer of materials.However,with the increase of the number,type and thickness of materials,the possible results of multi-layer combination are more and more,and it is more and more difficult to find the optimal solution to meet the demand.In order to solve the above problems,it has become a trend to use algorithms combined with multi-layer wave absorption theory and computer-aided optimization design.This master thesis studies the multi-layer wave absorption optimization design of genetic algorithm and its improved algorithm in 0.9-6GHz.Through the improvement of algorithm and optimization process,it well meets the needs of different optimization design,such as broadband,target segmentation,fixed intermediate layer,thinning thickness and so on.The analysis of algorithm optimization process and results shows that the algorithm optimization process design is reasonable.Finally,the corresponding relationship of material electromagnetic parameters is studied,which lays a foundation for the physical preparation of multi-layer optimization design results.The main contents and conclusions of the study are as follows:(1)The process of multi-layer wave absorption optimization design of genetic algorithm is given in detail,and the effects of filling definition fitness function and existing fitness function on the optimization results are compared and studied.it is found that the filling function defined by independent design is more accurate to express the optimization requirements and is more conducive to multi-layer optimization design.(2)According to the optimization requirements of broadband,target segmentation,fixed middle layer and thinning thickness,the optimization process of genetic algorithm is improved accordingly,and the expected optimization results are obtained.The analysis of each optimization process and results also confirms the rationality of the optimization process improvement.(3)In order to improve the optimization ability of genetic algorithm,the genetic algorithm is improved by adaptive and hybrid simulated annealing algorithm.By analyzing and comparing the optimization results,it is found that the results given by the two improved algorithms are better than the original genetic algorithm.Further comparative analysis of the optimization process of the algorithm shows that the improved algorithm mainly improves the evolutionary ability in the later stage of optimization,which is consistent with the initial theoretical assumption of algorithm improvement.(4)Based on the Maxwell Garnett mixing formula,the electromagnetic parameters of two kinds of absorbing materials with the same absorbent and different matrix materials are corresponding,and the corresponding processes and results are given.By analyzing the reflectivity error of the corresponding results of permeability and permittivity,it is found that this correspondence can be used in the case of low precision.