Mode-matching analysis of a waveguide junction formed by a circular and a larger elliptic waveguide

The paper presents the formulation of a waveguide junction formed by an elliptic and a circular waveguide using the mode-matching method. The junction studied is concentrically joined with the cross-section of the circular waveguide completely enclosed by the elliptic waveguide. By expressing the modal fields in both waveguides in terms of Bessel functions, exact closed-form expressions for evaluating the coupling integrals are obtained. Theoretical results compare well with measurements and published results