General Media And Plasma Time-domain Electromagnetic Scattering Spectral Element Analysis

Since the British scientist J.C. Maxwell came up with the Maxwell equations with a large number of experiments and creative thinking in1873, development of electromagnetism has made considerable progress as well as the application in fields of the radar, microwave/millimeter wave remote sensing technology, target stealth and recognition. Computational electromagnetics, a new technology to solve practical engineering requirements, is based on the basic theory of electromagnetism, combined with computer technology and mathematics method, and can simulate electromagnetic problems accurately and efficiently for targets.TDSEM is a novel time-domain method, which combines the finite element method with time domain spectral method for numerical analysis. It has some features such as low sampling density, high precision and rapid calculation speed. The spectral element method discussed in this paper is based on the wave equation, discreting computational domain with curved hexahedron, and adopting orthogonal Gauss-Lobatto-Legendre polynomial as the basis functions. Compared with FDTD, the TDSEM modeling has high degree of fitting; also, it reduces the number of unknowns because the meshing size of the spectral element method can be large. Compared with FEM, the mass matrix can be inverted quickly since it is diagonal or block diagonal in TDSEM.We use TDSEM to analyze the electromagnetic scattering and the electromagnetic characteristics of plasma in this paper. In order to solve open domain problems, we use appropriate boundary conditions to truncate the calculation boundary such as the first order absorbing boundary condition (ABC) and perfectly matched layer (PML). In the derivation of the source selection, this paper uses volume-excitation method. This paper also demonstrates some specific scattering examples, including pure metal, pure medium and mixed metal and medium example. Because of the tensorial and dispersive dielectric coefficient of plasma, it can be brought into solving wave equation in the three-dimensional case. Also, programme is compiled and debugged based on the TDSEM, plasma filter and plasma electromagnetic scattering characteristics is analyzed to verify the validity of this method.