Effective index of refraction in guide wave mode for ferrite based layered composites under different boundary conditions

We have studied the effective index of refraction for guided wave mode in periodic ferrite-dielectric composite using the equivalent transmission line approach. For the different boundary conditions including PEC, PMC, impedance and periodic condition, we derive the dispersion equations and then calculate the effective index of refraction. We find that for the boundary conditions the negative index happens in certain frequencies in TEy mode, but never occur in TMy mode. The analysis shows the ferrite based layered composite is an only-mu-negative negative index material.