The Four-Port Single Junction Circulator in Strip Line

The four-port single junction circulator in strip line offers the possibility of a more compact and less expensive structure than the heretofore required dual three-port units in tandem. One such four-port circulator has been described previously, although very little material has appeared in the literature on the theory of the device. Auld points out that an additional parameter is required for the four-port circulator compared to the three-port. Davies and Cohen have extended Bosma´s circulation equations to the four-port case and have included the scattering matrix analysis. Fay and Comstock have indicated a possible combination of modes of a disc structure which could provide a four-port circulator.