Study On High Frequency Methods Ofelectromagnetic Scattering From Largesize Targets

With the rapid development of modern electromagnetic technology,the research on the direction of high frequency band of electromagnetic wave in the field of communication and radar is developing rapidly.Therefore,it is of great significance to study and analyze the electromagnetic characteristics of large size targets in high frequency band.Considering the principle of local field,the electromagnetic coupling between scatterers can be neglected.Therefore,the high frequency analysis method has the advantages of low memory consumption and fast computation speed.This article mainly embarks from the theory of the electromagnetic characteristics of complex target analysis,studies the basic principle of high frequency analysis method and numerical analysis method,and analyzes the advantages of high frequency method when dealing with complex target,emphasizing the application of high frequency analysis method of physical optics method to solve the problem of electromagnetic characteristics of complex model,further research on the method of complex model and select the modeling techniques used in this study route,high frequency analysis method of target radar scattering cross section,python programming method to calculate the physical optics method is used to realize the complex model of radar scattering cross section value calculation problems in practical application.In this thesis,the basic theories and solutions of GO,PO and moment are introduced.Then the definition and solution of radar cross section and the difference between single and double radar cross sections according to the conditions of transmitter and receiver are described.In order to study the electromagnetic characteristics of large-size targets,a theoretical reserve is made.Secondly,this thesis introduces and compares the technical route of establishing the model of the target with 3dsmax.The methods of software built-in model modeling,two-dimensional line modeling,surface modeling,NURBS modeling and polygon modeling are introduced respectively,and the advantages and disadvantages of different modeling techniques are compared according to different modeling methods,and the polygon modeling technology is selected to establish the complex electric large size model in the research.According to the two common export model formats when the model is imported into calculation-sat format and STL format of the export data form continue to study,combined with the export format of the data information problem polygon modelingtechnology to build the model into editable polygon and according to the specific operation to prevent errors in the model calculation optimization.In this thesis,the calculation method of physical optics is described in detail.In this thesis,two important ideas of the physical optics method(PO)to deal with the scattering of the target-occlusion judgment and approximate treatment are studied.The method of single weight occlusion is mainly studied to distinguish the bright area surface and dark area surface by the Angle between the normal vector and the unit vector of incident wave,and the contribution of the dark area surface is ignored in the calculation.Numerical examples of two simple models-sphere model and triangular pyramid model are given.Finally,this thesis expounds the technical route of using python programming method to calculate the electric large size by using the high-frequency analysis method.The numpy library and the matplotlib library are two important third-party libraries of python in implementing the high-frequency method.Three modules in programming are introduced for the electromagnetic parameter setting,data read and write,the model according to the opposite piece is contribution to rest the dark area of another judge,then rest for every light another radar scattering cross section value calculation,the final will be in the form of data according to the vector sum computation model in setting good incident wave frequency,incidence Angle,polarization Angle of radar scattering cross section of environment value,and the data visualization processing.The calculation results in python are analyzed and compared with the calculation results in the software.According to the calculation results and calculation time,the calculation efficiency and calculation accuracy of the python target program are analyzed.