An S-Matrix Based Hybrid Method

Abstract

The use of S-Matrix theory by engineers and scientists to understand and design microwave systems has roots that are over sixty years old.  The basic idea behind the method is to decompose the scattering domain into sub-domains and to characterize the scattering physics in each by an S-Matrix.  These are then "connected" using simple matrix algebra to achieve an accurate approximation of the complete scattering problem. Of course the method is viable only if an accurate approximation can made to the S-Matrices in each sub-domain.  These approximations were computed analytically for simple structures and were obtained experimentally for more realistic and complicated scatterers.

This theory has more recently been used, in conjunction with numerical algorithms, to produce accurate and efficient hybrid schemes for several classes of scattering problems that are not amenable to either finite difference, finite element, or integral equation methods.  The novel feature here is to replace the experimental determination of the S-Matrix for a sub-domain by an accurate numerical approximation to it.