The equivalence of applying the Extended Boundary Condition and the continuity conditions for solving electromagnetic scattering problems

The equivalence of applying the Extended Boundary Condition and the continuity conditions of the tangential field components at sharp boundaries for deriving methods to solve electromagnetic scattering problems is demonstrated in spherical coordinates. We show that both conditions provide the same transition matrix to determine the unknown expansion coefficients of the scattered field in terms of vector spherical wave functions. In this way, a generalization of the Separation of Variables Method to non-spherical scattering problems is achieved which allows a unified mathematical description of different numerical techniques. (C) 1998 Elsevier Science B.V. All rights reserved.