A combination method for the spectral domain system matrix computation of larger microwave structures with thin layer environments

In the last years, the performance of integral equation solvers based on the Greenpsilas function of planar multilayered media could be further increased especially by reducing the numerical complexity of the standard method of moments (MoM) with the help of fast integral equation techniques employing an efficient matrix-vector product evaluation within the iterative solution process. These methods are based e.g. on conjugate gradient solvers attached to fast Fourier transformations (CG-FFT) combined with the complex image method or combinations of the latter method with the adaptive integral equation method (AIM) [Ling et al., 1996]. Other approaches make use of the fast multipole method (FMM) combined with the complex image method or a perfectly matched layer technique [Ginste et al., 2006]. In contrast to this, we have introduced in [Vaupel et al., 2006] a new kind of a fast integral equation solver directly based on the analytically available spectral domain Greenpsilas function of the multilayered environment. Using all these methods, only a small part of the fully populated system matrix must be computed explicitly whereas the remaining matrix related to far interactions is only implicitly involved in the matrix-vector product evaluation.