The Structure Scattering Analysis Of Small Scale Antenna Arrays

Total-and Scattered Field Decomposition technology (TSFD) is applied to Finite Element Method (FEM) for the structure scattering analysis of small scale antenna arrays in this paper. Compared to the traditional Huygens'surface approach which impresses the incident field on the connecting boundary lies between the total field region and the scattered field region, Volumetric Excitation (VE) method is applied to impress the incident field into the whole total-field region in this thesis, which results in the wave leakage reduced from -20dB to -120dB, and the precision of VETSFD-FEM has been greatly improved consequently. Equivalent functionals of total field and scattered field are obtained respectively, and first-order Mur absorbing boundary condition is used to truncate the computational area. Compared to Perfect Matched Layer (PML) application, the condition of resulting FEM matrix equation can be improved and the FEM analysis can be accelerated dramatically. And then, field distribution of the whole computational area is analyzed with conventional finite element method (FEM) scheme. For the sparse coefficient matrix of FEM equations, compressed storage technique and conjugate gradient method (CGM) is employed to reduce memory consumption and computational time. In the end, Radar Cross-Section (RCS) of target can be obtained by using the principle of equivalence and near-far-field extrapolation technique which is established by the electromagnetic distribution generated by presented VETSFD-FEM.Commercial software Patran is applied for geometry modeling and grid generation. Then RCS for metallic cube, dielectric slab, metallic cube of arrays, microstrip antenna and small scale antenna arrays has been calculated with VETSFD-FEM in this thesis and compared with the results simulated by commercial software. Good agreement validates the method and its implementation. The structure scattering for large scale periodic array is obtained by simply adding the far field of each sub-array. The associated calculation accuracy is not so satisfying for omitting the coupling between units and whole array boundary effects, but the computational efficiency is high. As a result, it can be used as an approximate estimation for electromagnetic scattering analysis of large-scale antenna arrays.