A simplified theory of the three-port junction ferrite circulator

A simplified theory of the three-port junction circulator is given. This theory is applicable to all three-port junctions which rely on the splitting of a pair of degenerate modes and gives the two circulation conditions of the three-port junction circulator in terms of the elements of the equivalent shunt resonator. This is done by first developing the degenerate normal-mode description of the resonator and then modifying it to allow for the known splitting of the resonant frequencies. The loaded-Q of the junction is also given. All the results obtained are consistent with the classical junction behaviour.