Enhancement of Phase-Shifting Nonreciprocity in Metamaterial Lines With Comb-Shaped Capacitive Stubs on the Normally Magnetized Ferrite Substrate

In this paper, enhancement of phase-shifting nonreciprocity is proposed by using metamaterial lines with comb-shaped capacitive stubs on the normally magnetized ferrite substrate. The insertion of capacitive stubs enhances the effective permittivity, i.e., effective propagation distance in one propagation direction due to edge-guided mode propagation along the comb-shaped stub edges. The nonreciprocity of the proposed structure was numerically compared with those of other types of metamaterial lines, and transmission characteristics of the prototype circuit were measured and reproduced by the numerical simulations, verifying the enhancement.