Analysis Of Broadband Electromagnetic Scattering Characteristics From Conducting Objects Based On Fast Dipole Method

The research of target wide-band electromagnetic scattering characteristics is the foundation of military and civilian technology development, and accelerating the analysis of wide-band electromagnetic scattering characteristics of target is the focus study for numerical calculation. Using the method of moments (MoM) to analyze broadband electromagnetic scattering characteristics of target can adopt frequency point calculation one by one, but the drawback lies in that the consumption of the memory is large and cost much more calculation time, especially the analysis of electrically large size targets are almost impossible to calculate. So the research of rapid algorithm owns important value.When the frequency band calculated is wide, we use limited frequency point information of frequency band to achieve the wide-band electromagnetic scattering characteristics as an important approach. This thesis is based on the idea and combines with rapid method to improve the efficiency of conductor target wide-band radar scattering cross section (RCS).Firstly, the thesis introduces the basic principle of MoM and the related basic concept of RCS.Then the concrete steps of electric field integral equation (EFIE) presented to solve the RCS of the three-dimensional conductor are given. At last, two calculation examples are shown to verify the effectiveness of the MoM.Secondly, a new fast algorithm-fast dipole method (FDM) applied to analyze electromagnetic scattering characteristics of electrically large size object is introduced. The method takes the equivalent dipole method (EDM) as the foundation and process the dipole interaction of far field approximately, which speeds up the solving process and has little impact on accuracy. This thesis is based on FDM to research conductor wide-band RCS. The calculation complexity and memory of FDM are analyzed in detail, and numerical examples show the accuracy and efficiency of the algorithm.Then, the thesis calculates conductor target wide-band RCS based on the impedance matrix rational interpolation method. Impedance matrix rational interpolation method is used to accelerate the filling of frequency band of non-interpolation point impedance matrix and has no effect on solving the matrix equation. In order to speed up the solution of the matrix equation, the rational interpolation impedance matrix is combined with the FDM and the preconditioned iteration technique to calculate near field preconditioned matrix and matrix interpolation, aims to save much time. Finally numerical examples show the good accuracy and high efficiency of the algorithm.Finally, the AWE technique is combined with FDM to solve wide-band RCS of conductor targets. Although the impedance matrices are need to store while the AWE technique is applied, just several frequency points are need to be analyzed based on the analysis of target wide-band RCS. Numerical example results show the hybrid method can reduce the calculation time effectively and own good accuracy.