Study On Scattering Characteristics Of Stealth Targets Based On Absorbing Materials

The study of electromagnetic scattering characteristics of stealth targets has important significance and application prospects in radar target detection and recognition.Coating absorbing materials on the target surface or using structural absorbing materials instead of raw materials can effectively reduce the Radar Cross Section(RCS).Therefore,the preparation of absorbing materials and the study of stealth effects and the RCS calculation of the coated target become the target One of the important topics of stealth.In thesis,a systematic research work is carried out based on the electromagnetic scattering characteristics of stealth targets by absorbing materials.The main work and research results are as follows:1.Designed a multi-layer absorbing material with good performance,and optimized the material thickness and absorption frequency band.First,the latest research progress of coated and structured absorbing materials is analyzed,the characteristics of different absorbing materials are classified and discussed,and the influence of the thickness of the absorbing material and the change of incident wave frequency on the absorbing performance of the absorbing material is analyzed.Then use the material parameters in the existing literature to compose a database containing eight materials,design and optimize the multilayer absorbing material based on genetic algorithm,and give different optimization schemes according to different optimized frequency bands.2.Exploring the application of coated absorbing materials,researching and realizing the algorithm for calculating the radar cross section of the target coated with multilayer media.Compared with the traditional method based on physical optics,this method considers the contribution of the edge diffraction field and improves the accuracy of the algorithm.Based on the algorithm in thesis,all the radar cross sections of land targets and high-altitude targets are calculated,and a good radar cross section reduction is obtained.In addition,according to the one-dimensional range image of the target,the position of the strong scattering source of the target is judged,and local coating is performed to change the scattering characteristics of the target.3.Based on structural absorbing materials,the application of radome is studied,and the characteristics of radome materials for wave-collecting heat-resistant stealth at home and abroad are analyzed.According to the parameters in the literature,the transmittance and reflectivity of the quartz/cyanate ester flat radome are calculated,and the genetic algorithm is used to optimize the multilayer structure radome.Finally,the far-field radiation of the antenna system is calculated according to the physical optics method,and the performance of the radome is analyzed according to the influence of the radome on the far-field radiation of the antenna.In thesis,the coated absorbing material is combined with the electromagnetic algorithm.Based on the optimized multilayer composite absorbing material,the analysis and calculation of the coated target achieve the reduction of the target radar cross section,change the scattering characteristics of the complex target,and The structural material is applied to the tangential oval radome,combined with the far-field radiation pattern of the antenna system to obtain the appropriate material thickness and bottom radius,and the performance of the radome is reasonably analyzed.