Quality Factor of the Waveguide Re-Entrant Turnstile Junction Circulator

One of the two independent variables entering into the description of the one-port complex gyrator circuit of a junction circulator is its quality factor. The other is the susceptance slope parameter. It determines both its gain bandwidth product and the upper frequency bound of this type of junction. The purpose of this paper is to investigate that of the partially recessed waveguide turnstile circulator using a quarter-wave-long re-entrant gyromagnetic resonator. The quality factor of this class of junction is essentially determined by the gyrotropy of the magnetic insulator, except for the penetration of the resonator into the housing of the junction. The other physical parameter of the junction may therefore be utilized to adjust the susceptance slope parameter of the gyrator circuit. The work undertaken here is in WR75 waveguide at a frequency of 13.25 GHz.