Dispersion surface of magnetostatic surface waves affected by perfect conductors

The dispersion relation of magnetostatic surface waves (MSSW) propagating in an arbitrary direction in a ferrite slab placed between two metal plates is derived and it is shown as a curved surface in Ω-ξ-ζ space, where Ω is the normalized angular frequency, ξ is the component of the normalized wave number in the direction of dc magnetic field and ζ is the component in the direction perpendicular to dc magnetic field and parallel to the slab surface. The dispersion surface is greatly deformed by changing the normalized spacings and between the slab and metal plates. The curve for (a dominant mode) of the Ω-ζ curves which constitute the dispersion surface is free of a cutoff wave number and intersects with Ω axis at specific frequency which is determined by the normalized magnetic field ΩHand , while the other curves for (higher order modes) have a cutoff wave number except in special cases. The cut-off wave number characteristics become curves. A detail discussion is given about asymptotic change of the dispersion surface in the neighborhood of Ω axis.