Recent COST284 developments in integral equation models with application to thick slots

In this paper, we combine a recently introduced approximate model for thick slots with an integral equation formulation to solve complex geometries. Although the discussed structures are essentially sections of waveguide filters including thick irises, the model is valid for open or hybrid problems like cavity-backed antennas. Other results will be presented at the conference. The key point of the approach is to include the thickness as an analytical correction in the Green´s function that must be used when solving slots with the equivalence principle. Two practical implementations of this correction factor have been discussed and implemented with excellent results for thicknesses up to one tenth of the wavelength