Spectral domain analysis of finlines with composite ferrite–dielectric substrate

An analysis of finlines with a composite substrate consisting of a dielectric layer and a ferrite layer magnetized with a DC external magnetic field is presented. The spectral domain technique is used to determine both propagation constant and characteristic impedance. A direct approach is used to arrive at the determinantal equation. Numerical results are presented as illustrations for various cases. The feasibility of such finlines for the realization of isolators, as has been suggested by other authors, is also confirmed.