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 CrankNicolson padé(1,0) The rotating parabolic equation method 
CLC  O441.4 
Type  Master's thesis 
Year  2010 
Downloads  66 
Quotes  0 
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, highfrequency approximation method can only solve a large object scattering, the objectives of the mediumsize 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 twodimensional forward parabolic equation, twodimensional backward parabolic equation, cylindrical coordinate system parabolic equation, threedimensional 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 CrankNicolson difference scheme and pade(1,0) in the twodimensional difference scheme. Then introduce the principle of perfectly matched layer (PML), and derive the difference scheme of CrankNicolson difference scheme and the PML pade(1,0). Accurate only within a small angular range of nearaxis direction for the parabolic equation, we introduce a rotating parabolic equation method, using a rotary parabolic axial and resetting the incident direction and the object boundary conditions, can be calculated in each direction RCS. Scattering problem in threedimensional objects, derived differential format formula pade(1,0) differential format also gives the PML in the differential formula. The threedimensional 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 semimanually 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.