Hybrid dyadic-mixed-potential and combined spectral-space domain integral-equation analysis of quasi-3-D structures in stratified media

Planar circuits and antennas in stratified media are efficiently analyzed using an integral-equation formulation with a spectral-domain approach to construct the required Green\´s functions. This efficiency is largely lost when arbitrary three-dimensional (3-D) structures have to be analyzed. We, therefore, focus attention on "quasi 3-D" structures, which, although not fully 3-D, are still seen to cover most practical problems. The formulation of the electric field is adapted to the geometry as a hybrid dyadic-mixed-potential form. Evaluation of all z, z^\´-dependent parts of the reaction integrals is done analytically in the spectral domain. The remaining evaluation is done in the space domain with a mixed-potential formalism. We obtain a combined spectral-space domain approach to solve the integral equation. Numerical results demonstrate the applicability of the method to (most) 3-D problems that occur in planar stratified media.