Split frequencies and susceptances of the three-port junction circulator from an experimental determination of the complex gyrator circuit

The adjustment of the classic three-port circulator involves an in-phase eigen-network and a pair of split counter-rotating ones. The purpose of this paper is to use some recent relationships to experimentally extract the split susceptances of the counter-rotating immittances and the susceptance slope parameter of the junction by having recourse to a one-port measurement of its complex gyrator circuit. This is done under the assumption that the in-phase eigen-network of the junction may be idealized by an electric wall. The split frequencies of the counter-rotating eigen-networks of the circulator may also be deduced from this characterization and are in good agreement, under the same assumption, with those derived from one-port measurements on a terminated circulator. The latter arrangement does not, however, allow the split susceptances of the counter-rotating eigen-networks to be deduced. © 2008 IEEE.