Research And Application On Efficient Numerical Modeling Method For Complex Thin Dielectric And Metallic Composite Structure

Complex thin dielectric/PEC composite structures have very important applications in electromagnitic engineering,so the research on efficient numerical modeling techniques for such structures is of great significance.Such complex composite structures generally have the characteristics of electrically large in size,multi-scale and inhomogeneous material,which lead to a poor matrix state,large resource consumption,difficult geometric modeling and low efficiency in electromagnetic calculation.At present,great progress has been made in the study of efficient solution of complex PEC structures,but the research on efficient solution of complex PEC-dielectric composite structures still needs to be improved,especially the dielectric part also has the characteristics of electrically large in size,multi-scale and inhomogeneous material.The multi-scale of the dielectric part is that the electrical dimension in the thickness is much smaller than the working wavelength,and the other dimensions are much larger than the wavelength.Complex composite targets with the above characteristics are very challenging in efficient geometric modeling and electromagnetic modeling,and are also one of the hotspots in electromagnetic computing research today.In this dissertation,two simplified volume basis functions are proposed for complex composite structures with planar and curved thin dielectric,and a simplified strategy for high-order volume basis functions is proposed.The construction of these simplified basis functions is to improve computational efficiency and reduce computational resource consumption.Then,based on the above theory,two domain decomposition methods(DDM)and an acceleration method of matrix filling are developed for electrically large and multi-scale composite thin dielectric and PEC targets,which facilitate geometric processing,greatly improve convergence and improve the computational efficiency and capability of complex composite structures.Firstly,a simplified prism vector(SPV)basis function is proposed for thin dielectric structures.Compared with the commonly used SWG basis function,the discrete problem of target geometry is effectively alleviated,the number of unknowns is reduced,and the consumption of computing resources is decreased.Compared with the traditional triangular prism basis function,the proposed basis function has higher simulation efficiency because it avoids the calculation of the volume integrals.Then,this dissertation proposes a I-VSIE domain decomposition method(VSIEDDM)for the complex planar thin-layer composite structure.The proposed method accelerates the convergence.In addition,geometric modeling is more flexible and convenient.Besides,the equivalent dipole-moment method is used to speed up the matrix filling.In this method,an equivalent dipole model based on SPV basis function is proposed.Compared to the conventional equivalent dipole model,the proposed model only needs to calculate less nummerical integrations within the distance threshold.So it has a higher filling efficiency.Moreover,this dissertation proposes a II-VSIE-DDM for the complex electrically large curved thin-layer composite structures.It relieves the difficulty of mesh generation of the electrically large targets and improves the convergence and computing performance of VSIE.Under the framework of this method,the three partitioning strategies are proposed to improve the flexibility of geometric modeling.Finally,this dissertation applies the triangular prism high-order hierarchical vector basis function to the volume integral equation,and proposes two simplified strategies for the high-order basis function for thin dielectric structures.Compared with the traditional triangular prism high-order hierarchical vector basis function,the simplified basis function retains good accuracy while reducing the number of unknowns,memory usage,iteration number and time consumption.This dissertation systematically studies the high-efficiency numerical modeling method for complex thin-layer composite targets.The purpose is to provide an theory and technology for this problem and hotspot,and further lay a foundation for practical applications.