In this work, we propose a novel integral equation formulation that allows the efficient analysis of multiport H-plane microwave devices including arbitrarily shaped metallic and/or dielectric posts. The system of integral equation that models a given H-plane microwave device is written in terms of mixed-potentials, whose unknowns are equivalent electric (J) over right arrow or magnetic (M) over right arrow surface current densities. These unknown currents are defined, after the aplication of the Surface Equivalence Principle, on the discontinuities between the input and output waveguide ports and a rectangular cavity, as well as on the dielectric and/or metallic posts contour. The, so called, original problem is split into several equivalent problems, defined in different regions, that are coupled each other by the aforementioned unknown surface current densities. The kernel of the integral equation is expressed making used of Green's functions that takes into account the boundary conditions corresponding to the region where the considered equivalent problem is defined; namely, parallel plate Green's functions, 2D rectangular cavity Green's functions or unbounded medium Green's functions. Series acceleration techniques such as the Kummer's transformation and the Ewald method has been employed in order to improve the efficiency when computing the parallel plate and 2D rectangular cavity Green's functions. Two simulation examples are presented, comparing the results provided by the novel integral equation technique to those retrieved with a finite elements software tool (ANSYS HFSS). A very good agreement between both method has been obtained, showing the accuracy and efficiency of the technique proposed in this contribution.
