Improving the speed of the Method of Moments technique in large body scattering problems using the sparse matrix method

The Method of Moments (MoM) when applied for scattering analysis of a large body, generates a dense matrix. In this paper, a sparse matrix is generated from the dense matrix. The thresholding elemental method is applied to obtain a sparse matrix, by assuming that the electromagnetic interaction between sufficiently far away elements is zero. This technique is applied to compute the bistatic radar cross section (RCS) of canonical shapes and a complex shaped aircraft. It is found that for a maximum inaccuracy of 2 dBm² in RCS, the amount of sparsity generated can be in the range of 40 to 75%, and the corresponding CPU time saving will be of the order of 8 to 34% for objects of different size. It is also observed from the analysis, that with increasing electrical size of the scatterer, the sparsity and hence saving in CPU time increases.