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Hybrid Methods Based on EB-FEM and Their Applications to the EM Problems of Electrically Large Complex Cavities

Author: HeXiaoXiang
Tutor: XuJinPing
School: Nanjing University of Aeronautics and Astronautics
Course: Communication and Information System
Keywords: Electromagnetic properties Electrically large complex cavities Vector finite element method Iterative Physical Optics Impedance boundary condition Domain Decomposition Method Perfectly matched layer Bi-conjugate gradient method Symmetric SOR
CLC: O441
Type: PhD thesis
Year: 2003
Downloads: 669
Quote: 9
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Abstract

Electrically large complex cavities electromagnetic properties analysis is an important computational electromagnetics research content, its stealth and anti-stealth technology, electronic equipment electromagnetic compatibility analysis and design of microwave devices related significance. Vector finite element method (EB-FEM) is an effective analysis of complex electromagnetic characteristics of the target numerical method. Whitney back in 1957 has described the vector finite element method based discrete element idea, but until the 1980s, EB-FEM in computational electromagnetics was only aware of the importance. Since then, EB-FEM study has been booming. Since the 1990s, J. M. Jin and J. L. Volakis other scholars EB-FEM combined with other methods successfully for many electromagnetic problems were analyzed. In this paper, EB-FEM-based, electrically large complex cavities for the analysis of the electromagnetic properties of an object, for EB-FEM and iterative physical optics (IPO), domain decomposition method (DDM), impedance boundary condition (IBC), an exact match layer (PML) and the Mur absorbing boundary conditions with the combination of algorithms and non-border IPO Perfect Conductor theoretical model were studied. The paper also discusses some of the memory compression technology and EB-FEM method for solving equations quickly. Paper include the following: the iterative physical optics (IPO) of sub-domain connection method combined with EB-FEM, we propose a new hybrid approach -IPO/FEM France. Established IPO / FEM hybrid method mathematical model, and applied to the analysis of electrically large complex structures cavity electromagnetic scattering. Discusses the finite element equations coefficient matrix compression and storage technologies and other memory tightening method saves a lot of memory consumption. Finite element equations using bi-conjugate gradient method for solving symmetric SOR right through equations coefficient matrix for improved behavior, improved bi-conjugate gradient method based on the finite element method in a complex mix of technology and its cavity TV Electromagnetic Analysis iterative algorithm for solving the speed and stability. The iterative Physical Optics (IPO) method is extended to non-Perfect Conductor borders the electromagnetic scattering analysis, built a theoretical model of impedance boundary of the IPO and IPO application of this method of analysis to promote the simple geometry of electrically large dielectric coating apply cavity electromagnetic scattering. On this basis, the improved IPO with FEM combines the engineering practice is common with complex geometries terminal electrically large dielectric coated cavity electromagnetic scattering analysis. As media IPO application region can be directly applied to process, avoiding the use of EB a FEM study, saving a lot of computing time and memory consumption. Discusses the medium coated surface Green's function solution method will be applied to the promotion of IPO method can further improve the accuracy of the method. Studied the domain decomposition method (DDM) and EB an FEM, boundary integral equation (BIE) Combination of hybrid algorithm a DDM / F EM a BIE method. Discussed the overlapping DDM, non-overlapping DDM DDM and over-relaxation iterative process and the EB a FEM application. This hybrid method using three-dimensional electrically large open cavity electromagnetic scattering characteristics were analyzed, so as to apply to analyze electrically large low frequency provides a new way. On this basis, the DDM and EB an FEM, physical optics, physical theory of diffraction combined with a deep analysis of the three-dimensional conductor electrically large cavity on the electromagnetic scattering characteristics. The perfectly matched layer (PML) is applied to the FEM EB a waveguide discontinuity problem handling the media. Discussed the waveguide and the dielectric constant of the dielectric block characteristics and how the relationship between S-parameters studied PML different structure on S-parameter solution accuracy, draw some reference value for the engineering design of the conclusions. The Leontovich IBC FEM combined with EB a multilayer dielectric coating on the inner wall of electrically small open cavity for electromagnetic scattering analysis included in the multiple reflection of electromagnetic waves inside the medium, Kwong EM method improves the accuracy of IBC.

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