Even and odd mode cut-off parameters of pairs of ridges in rectangular waveguide using a mode matching solver

A waveguide geometry of some interest consists of a symmetrical pair of ridges in a rectangular waveguide. The paper gives the even and odd mode cut-off spaces of such a structure in addition to its corresponding standing wave patterns. The classic power-voltage, power-current and voltage-current definitions of impedance of the two solutions are also evaluated. The calculations are based on a mode matching procedure and are verified separately using a finite element solver. A knowledge of these parameters is sufficient for the design of a proximity, reverse, directional coupler.