Dissertation > Mathematical sciences and chemical > Physics > Electromagnetics,electrodynamics > Electricity and Magnetism > Electromagnetic waves and electromagnetic fields

Parabolic equation in electromagnetic scattering analysis

Author HuangHanQing
Tutor FanZhenHong
School Nanjing University of Technology and Engineering
Course Communication and Information System
Keywords Parabolic equation method Electromagnetic Scattering Perfectly Matched Layer Crank-Nicolson padé-(1,0) The rotating parabolic equation method
CLC O441.4
Type Master's thesis
Year 2010
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Numerical methods such as electromagnetic calculations of moment method (MOM) and the finite element method (FEM), finite difference time domain (FDTD) to solve the scattering of electrically small objects, but in the calculation of the scattering of the large object, The computer's configuration requirements are too high. Ray tracing, physical optics, high-frequency approximation method can only solve a large object scattering, the objectives of the medium-size its calculation results error. Parabolic equation (PE: Parabolic Equation) method is to contact a bridge of these methods, it is an approximate wave equation form, assuming that the electromagnetic energy spread in the axial direction along the parabolic cone area. Preliminary research and computing applications, the parabolic equation method mainly includes the following aspects: First PE principle of the method, such as a two-dimensional forward parabolic equation, two-dimensional backward parabolic equation, cylindrical coordinate system parabolic equation, three-dimensional parabolic equations and vector parabolic equation. Then the numerical solution of the above equation is a differential form, so we use the differential method, free space Crank-Nicolson difference scheme and pade-(1,0) in the two-dimensional difference scheme. Then introduce the principle of perfectly matched layer (PML), and derive the difference scheme of Crank-Nicolson difference scheme and the PML pade-(1,0). Accurate only within a small angular range of near-axis direction for the parabolic equation, we introduce a rotating parabolic equation method, using a rotary parabolic axial and re-setting the incident direction and the object boundary conditions, can be calculated in each direction RCS. Scattering problem in three-dimensional objects, derived differential format formula pade-(1,0) differential format also gives the PML in the differential formula. The three-dimensional problem of a significant feature is the great unknown quantity have some difficulty in solving this, we introduce the solution of large sparse matrix. Finally, a Double Pass method. In the end of this article, we have given a description of the shape of the target surface triangles metadata conversion generation technology, the use of this technology for the parabolic equation cubic grid can be easily generated by the ANSYS triangles transformed into a cubic grid, do not go through the design drawings, manufacturing drawings manually or semi-manually constructed model, reducing the workload; modeling methods and procedures have versatility, can be programmed to complete the corresponding modeling. Parabolic equation method is an important theoretical basis of the the scattering target analysis and radar design has important significance for the target radar detection and target identification.

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