The higher order mode stripline circulator using a gyromagnetic disk resonator

At millimetre wavelengths the construction of a stripline circulator using a gyromagnetic disk resonator becomes difficult because of its size, and the scaling of the material gyrotropy is no longer valid. This paper summarises some existing relationships of the first higher order mode, and places an upper bound on the gyrotropy of the weakly magnetised model. Provided the coupling angles are small and the radian ground place spacings are equal, the gyrotropy necessary to establish the gyrator conductance of the first order mode is half that of the dominant mode one, while its quality factor is twice that of the latter.