S-matrix of a slot-coupled circular to rectangular waveguide T-junction

An analysis of a slot-coupled T-junction consisting of a circular to rectan gular waveguide is presented. The Galerkin method of moments with entire do main sinusoidal basis functions is used to solve the slot aperture electric field integral equations taking into account finite wall thickness. The sl ot coupler characteristics are deduced, including resonant length and domin ant mode scattering. The theoretical results on the magnitude of the s-para meters are compared with experimental results. The effect of the variation of diameter of the circular waveguide as well as the width of the slot on t he resonant length of the slot is also studied.