Passband Control of Surface Magnetostatic Waves by Spacing a Metal Plate Apart from the Ferrite Surface

The effect of a metal plate on the propagation characteristics of surface magnetostatic waves (SMW) propagating perpendicular to an external dc magnetic field was studied by varying the spacing of the metal plate from the ferrite surface. Continuous passband control is obtained by changing the spacing from zero to infinity and the existence of a partial stopband for the interchange of the input and output ports is also obtained in addition to the disappearance of nonreciprocal propagation for a finite spacing of the metal plate.