Magnetostatic-Wave Propagation in a Finite Yig-Loaded Rectangular Waveguide.

Abstract

The objective of this investigation is to study magnetostatic-wave propagation in a rectangular waveguide loaded with a finite YIG slab, to underst and the effect of physical parameters on the dispersion and group time-delay characteristics, and to obtain better design criteria for magnetostatic-wave devices. An analysis was carried out for two basic geometrical configurations: (1) a YIG slab of arbitrary thickness placed inside a waveguide in contact with each sidewall and (2) a thin YIG slab of finite width placed symmetrically inside a waveguide such that there is an equal air gap between the slab and each sidewall. For each of these basic geometries, the magnetic bias field was assumed to be either parallel or normal to the slab in the transverse plane of the waveguide. For Case 1, the mode analysis technique was used to obtain the dispersion relations while in Case 2 the integral equation method was used to derive the approximate dispersion relations. Numerical simulations were carried out for various geometrical configurations. Sample numerical calculations of the propagation constant and delay characteristics are presented in the frequency range of 4 to 10 GHz. These numerical results were obtained as a function of the geometry and magnetic field. The results obtained from the numerical simulation will be important in the design of magnetostatic-wave devices. The general formulation presented in this study contains all the information given by the degenerate cases previously published. The special cases of interest are obtained simply by permitting some of the dimensional parameters to take on their limiting values.