COM-Based Perturbation Analysis of Nonlinear Signal Generation in I.H.P. SAW Resonators

This paper describes the first-order perturbation analysis of nonlinear responses in surface acoustic wave (SAW) resonators on the LiTaO
3
/SiO
2
/Si structure, where bulk wave radiation is negligible near the main resonance while longitudinal resonances are not. The coupling-of-modes (COM) theory is employed as the platform for both the linear and nonlinear response analyses. Stress and dielectric flux are assumed to be generated by nonlinear mixture of linear strain and electric fields proportional to the SAW displacement and applied voltage, respectively, and are introduced in the COM equations as excitation sources. The simulated third harmonic responses agree well with the experimental ones including that caused by longitudinal resonances, and effectiveness of the present method is demonstrated.