Standing-wave solution of 3-port junction circulator with 1 port terminated in a variable short circuit

The insertion loss between ports 1 and 3 of a 3-port junction circulator terminated in a variable short circuit at port 2 varies between one and three times that between adjacent ports. Whereas a phcinenological explanation of this behaviour is not possible on the basis of a sequence of travelling waves, it may be understood by taking a linear combination of standing-wave patterns in an ideal circulator. The minimum attenuation condition is obtained by superimposing two such solutions in antiphase. This combination leads to a reversal in the direction of circulation in the junction, and in this case the insertion loss becomes the loss between adjacent ports. The maximum attenuation is obtained by adding the two standing-wave solutions in phase.