Mixed-mode S-parameter extraction for differential microstrip to waveguide transitions

This paper presents a practical method to extract mixed-mode S-parameters of a micro-strip-to-waveguide transition that is fed by a differential micro-strip line. The measurements, however, can be carried out easily by utilizing a standard two-port vector network analyzer and using three different waveguide standards from a commercial waveguide calibration kit (short, offset short and termination). With this method a wide-band V-band transition from 50 GHz to 75 GHz was characterized.