Induction probing of magnetostatic delay line fields

Recently, significant advances have been achieved in the development of tunable microwave (1-20GHz) signal processing elements utilizing magnetostatic waves (MSW) propagating in magnetically biased films of Yttrium Iron Garnet (YIG). The devices use transversal filtering techniques similar to those utilized in surface acoustic waves (SAW) technology. Essential to transversal filtering techniques is a detailed knowledge of the field distribution in the wave propagation media. This work reports initial experimental results of induction probing of the spatial distribution of the MSW field in both magnetostatic surface (MSSW) and forward volumn (MSFVW) wave delay lines. The experimental work of this paper indicates a number of conclusions which are of significance to MSW devices; 1. YIG film anisotropy strongly effects MSW propagation and the relative orientation of the bias field, crystal axes and propagation direction are critical to optimum delay line design. 2. Beam spreading and steering effects are significant and strongly dependent on the relative orientation of bias field, crystal axes, and propagation direction.