Broad Banding of E-Plane Resonance Isolators by Dielectric Loading

Abstract

ABSTRACTConventional E-plane ferrite resonance isolators have narrow bandwidth because the location of the two planes, where the H-vector components are circularly polarized, is frequency dependent. Theoretical analysis shows that a broad band performance can be achieved by loading the isolator with a dielectric slab having low losses and high dielectric constant. Experimental resonance isolators using thin rectangular ferrite slab have been constructed for the X-band with and without the dielectric loading. The frequency band for isolation greater than 20 db. is about 800 Mc/s. for the conventional isolator and increases to 2000 Mc/s. (8·7–10·7 kMc.) by loading with a slab of dielectric constant 16. The dielectric loaded isolator does not cover the entire X-band because of the narrow linewidth of the ferrite. The resonance can be broadened by using inhomogeneous magnetic field. Typical performance data of the broad band isolator using dielectric loading as well as inhomogeneous magnetic field is given be...