S-parameters extraction for wide-band transition from coupled microstrip line to waveguide by the LRdR method

This paper presents a practical method for extracting the S-parameters of a transition from a coupled microstrip line to a rectangular waveguide. By utilizing three standards (load, reflect, delayed reflect) for the waveguide port, the S-parameters (in both differential and common modes) of the transition can be calculated. A wide-band transition was tested to validate the calculation, and the results were in good agreement with expectations. This method is generic in the sense that it is suitable for other kinds of transitions, for instance, coplanar waveguide to waveguide, or coaxial line to waveguide, etc.