MODE PROFILES IN WAVE-GUIDE-COUPLED RESONATORS

Surface acoustic wave (SAW) waveguide-coupled resonators are of consid erable interest for narrow-band filter applications, though to date th ere has been very little published on the acoustic details of their op eration. As in any resonator, one must fully understand its mode struc ture and herein we study the SAW mode profiles in these devices. Trans verse mode profiles in the resonant cavity of the device were measured at various frequencies of interest using a knife-edge laser probe. In addition we predict the mode profiles for the device structure by two independent methods. One is a stack-matrix approach adapted from inte grated optics and the other is a conventional analytical eigenmode ana lysis of the Helmholtz equation. Both modeling techniques are in good agreement with the measured results.