Analysis of multilayer inset dielectric guides containing magnetised ferrites

The spectral domain approach is extended to analyse the nonreciprocal propagation characteristics of multilayer inset dielectric guide structures containing magnetised ferrites. Additional advantages offered by the extended approach are illustrated. Good convergence is obtained and the accuracy of the analysis is confirmed by comparison with available computed and measured data for a two-layer dielectric-filled inset dielectric guide (IDG) and a double-layer dielectric-ferrite finline. Numerical results for various multilayer IDG structures are presented with respect to nonreciprocity and bandwidth. Compared to a two-layer structure which does not exhibit adequate nonreciprocity, two three-layer structures offer much higher nonreciprocity, which is adequate for the development of efficient nonreciprocal phase shifters. Addition of a slotline at the air-groove interface is found to increase the useable bandwidth. These slotline loaded three-layer structures should find useful applications to nonreciprocal devices with high nonreciprocity and wide bandwidth