Theoretical predictions and experimental results for transverse modes in SAW cavities

This paper presents experimental and theoretical results for the lowest two mode separation in transversely coupled resonators. The theory is based on the stacked matrix approach which allows analysis of an arbitrary number of coupled waveguides. A family of curves of mode separation versus normalized aluminum film thickness is generated for various beam widths and waveguide coupling regions. Analysis includes the material velocity anisotropy and aluminum film layer velocity effects. The results of the theoretical analysis show the effects of the predicted mode separation when including the isotropic and anisotropic velocity effect on quartz for various device parameters. The mode separation family of curves are then compared versus measured transverse coupled resonator data for various device configurations. The experimental and theoretical predictions show good agreement. Results of these curves demonstrate that there are optimum values of aluminum film thickness for a given set of device parameters chosen and examples will be presented