On the scattering matrix formalism for electromagnetic modelling

The use of a collection of scattering matrices coupled with addition theorems as a framework for general electromagnetic problems is discussed. The author presents the basic machinery, illustrates some assumptions necessary to make this approach viable, and presents some directions for further research. This work began as an investigation of the effect of mutual coupling and was motivated by the desire to have an analytic theory that was nearly as accurate as the moment methods. Scalar modes and a scattering matrix were used instead of the traditional vector modes. The vector problem was solved inside a closed surface (such as a sphere) and the scattering matrix acted as an accountant of the relative strengths of the modes. In addition, the method is very closely related to the generalized multipole techniques.<>