ABSTRACT
This chapter is concerned with the Green’s function surface integral equation method (GFSIEM) for three-dimensional scattering problems. Compared with Chapter 8, retardation will now be taken fully into account. The same problems can in principle be considered as with the Green’s function volume integral equation method (GFVIEM) considered in Chapter 6. With the GFVIEM it was necessary for large problems to, for example, use cubic discretization elements placed on a cubic lattice in order to obtain a discretized integral equation in the form of a discrete convolution, since this allowed the use of memory-efficient iterative methods and fast calculation of matrix-vector products by using the FFT algorithm. However, cubic elements give a stair-cased representation of the surface of a scatterer, which may lead to calculated fields inside especially metallic scatterers with large deviations from the correct value. Such structures require a better representation of the scatterer surface, and this is achieved when using the GFSIEM. The discretization of a surface instead of a volume also means discretization in two dimensions rather than three dimensions, with a resulting dramatic decrease in the number of coefficients in the resulting matrix equation. For structures with cylindrical symmetry it was found in Chapter 7 that the GFVIEM could be reduced to a series of problems with discretization in two dimensions. Here, the GFSIEM further allows us to reduce such problems to a series of problems with discretization in only one dimension.
