The use of the FFT for the efficient solution of the problem of electromagnetic scattering by a body of revolution

The authors consider the further enhancement of the computational efficiency in the electromagnetic scattering of large bodies of revolution (BOR) with a view to making it practical to solve large-body problems. The problem of the electromagnetic scattering of a perfect electrical conducting (PEC) BOR is considered, although the methods provided can be applied to multilayered dielectric bodies. In most methods used, the generation of the elements for the method-of-moments matrix consumes a major portion of the computational time. It is shown how this time can be significantly reduced by manipulating the expression for the matrix elements using the fast Fourier transform (FFT). A technique is also presented for extracting the singularity of the Green´s function that appears within the integrands of the matrix diagonal. The extraction further enhances the use of the FFT and provides an exact analytic expression. Using this method, the computational time can be improved by at least an order of magnitude for large bodies, compared to existing algorithms.<>