A theoretical three-port coaxial-line rectangular-waveguide model and its application to millimeter-wave structures

A theoretical three-port model for a coaxial-line rectangular-waveguide junction is described and evaluated using several different realistic millimeter-wave mount structures. The model is found to be usable with good accuracy over a large variation in mount dimensions. The model is specifically applied in calculations of the embedding impedance seen by the diode in a millimeter-wave frequency multiplier. The three-port model is an improvement over simpler models hitherto used for devices such as millimeter-wave frequency multipliers because it takes into account all parameters in the mount.<>