Direct computation of the admittance parameters of a cubic junction with arbitrarily shaped access ports using the BI-RME method

The admittance matrix representation of a six-port cubic junction with arbitrarily shaped access ports is investigated. An alternative technique, based on the theory of cavities and the boundary integral-resonant mode expansion (BI-RME) method, is proposed for the direct computation of the admittance parameters of this general waveguide multiport junction. The application of this procedure completely avoids the physical segmentation of the junction, thus always providing stable numerical results. Furthermore, the numerical efficiency of this direct technique has been increased by closing analytically some of the infinite series present in the formulation. To show the advantages of this analysis technique, first the efficient connection of an H- and an E-plane T-junction through a common side port with rounded corners has been considered. A magic-T junction with rounded corners in the two side arms has also been studied. Prototypes of these two novel devices have been manufactured and measured for verification purposes.