Based On Scattering Of High-frequency Electromagnetic KD-Tree

The radar cross section (RCS) is an important parameter of the object feature, and how to predict it efficiently has been a hot topic in the computational electromagnetics society. The numerical methods in computational electromagnetics can be categorized into full-wave method, hybrid high-frequency/low-frequency method and high frequency method. Compared to the full-wave method and hybrid high-frequency/low-frequency method, the high frequency method is efficient for electrically large object.In this thesis, the RCSs of electrically large objects have been investigated with the shooting and bouncing ray (SBR) method. In this method, the rays representing the incident fields in a geometrical optical (GO) manner are used to determine the resulting equivalent surface currents, and finally the resulting field contributions at the given observation points are derived by the physical optical (PO) integration. Besides the first-order scattered fields, the SBR provides more accurate results by including the scattered fields arising from multiple bounces. The main contributions of this thesis are:Firstly, both the stack KD-Tree and rope KD-Tree are adopted to accelerate the ray tracing process in the SBR, and the efficiency of () has been investigated. Secondly, the second order Bezier surface modeling technique has been used to improve the accuracy of the results, in which the Newton’s iteration method is employed to find the intersection point. Thirdly, both the equivalent edge currents (EEC) and the truncated wedge incremental length diffraction coefficients (TW-ILDC) methods have been combined with the SBR to improve the accuracy of results. Fourthly, the program of SBR based on KD-Tree is parallelized with the OpenMP technique. Finally, the simulation software of SBR method has been developed based on Gmsh kernel to analyze electromagnetic scattering from electrically large objects.