Research On Complex Target FDTD Mesh Generation And Optimization

Finite-Difference Time-Domain(FDTD)method has great significance for the study of the scattering properties of the target.With the application of Finite-Difference Time-Domain is more and more extensive,the traditional analytical methods used for simple targets have great limitations,often there are problems with the discrete size of FDTD grids for complex targets and the computational efficiency of the overly large and complex target grids.The FDTD mesh generation technique is a key processing step of the FDTD algorithm,which is related to the accuracy and practicality of the FDTD calculation result.The dissertation develops a method for meshing complex targets based on Finite-Difference Time-Domain(FDTD)method,achieved a conventional FDTD mesh generation method for complex target models and an optimized FDTD mesh generation method with octree partitioning is implemented.Through the meshing of a typical three-dimensional space model,the advantages and disadvantages of the two meshing methods are compared and analyzed.,through the meshing of computer CPU consumption,memory space occupied,the same model grid using time and other performance data for comparative analysis.The results show that the computational efficiency of the optimized FDTD meshing method is much higher than that of the conventional FDTD meshing method.The paper by using numerical method of optimization of the three-dimensional mesh generation FDTD method,the main work: The dissertation focuses on the Finite-Difference Time-Domain method and briefly introduces the basic principles of the ‘Yee's cell grid structure and the FDTD method and the electromagnetic field iteration formula.Through AutoCAD software to achieve the establishment of a complex target model.Using AutoCAD and 3DMax to realize the mutual guidance of model files,the OBJ model file of triangle mesh model file based on triangle surface element was obtained.Using the method of intersection detection of a point in the range of the ray and the triangular facet element,the step of finding the intersecting ray and the plane of the triangular facet element is omitted,and the ray tracing algorithm is accelerated.A conventional FDTD meshing method is implemented.An octree partitioning method was introduced to optimize the FDTD meshing method.The bounding box theory and the separation axis theorem were used to realize the intersection detection of bounding boxes and triangular facets,the intersection detection algorithm of ray and bounding box is used to calculate the intersection of the ray and the triangle element in the bounding box to reduce the number of ray intersections and speed up the meshing efficiency.The ‘Yee's cell grid is generated by the intersection of the ray and the triangular surface element,and the mesh of the target area is filled with media,and the special grid is processed specifically to improve the accuracy of ‘Yee's cell grid model.The OpenGL graphics library is used to realize the visualization of ‘Yee's cell grid model,and the basic functions such as mouse operation,model zoom-in and zoom-out,and rotation are realized.The calculation of RCS of a typical three-dimensional target verifies the correctness and reliability of the program.By calculating and analyzing RCS of a complex target,it is proved that when the optimized FDTD meshing method is u sed to divide the complex target mesh,the splitting efficiency is improved and the computer resource is reduced.Improved grid accuracy improves technical support.