Efficient analysis of a cubic junction of rectangular waveguides using theadmittance-matrix representation

In the paper an efficient and accurate method, based on the multimode-admit tance-matrix representation and the theory of cavities, is proposed for the analysis of a six-port 'cubic' junction composed of the orthogonal interse ction of three rectangular waveguides. Very simple closed-form analytical e xpressions are explicitly detailed for all matrix elements of this basic ke y building block. More general waveguide multiport junctions, composed of a central cubic junction with arbitrarily shaped waveguide access ports, are also studied using a segmentation procedure. To validate the theory, numer ical results are first discussed for a standard rectangular waveguide six-p ort cross junction. Finally, the analysis method proposed is also successfu lly applied to H- and E-plane T-junctions whose side arms are waveguides wi th rounded corners.