Perturbation Analysis of Nonlinearity in Radio Frequency Bulk Acoustic Wave Resonators

This paper reviews perturbation analysis of nonlinear responses in radio frequency (RF) bulk acoustic wave (BAW) resonators. Two approaches are given. One is based on the 1D wave theory, and another is derivation of the equivalent circuit under a few simplifications. It is shown that second- and third-order harmonic responses in RF BAW devices can be simulated well. The circuit is extended to include multiple transverse mode resonances. The circuit also works well for this case, and it is explained why nonlinear responses by transverse resonances are more emphasized than those by the main resonance. Finally, the perturbation analysis is applied to the RF SAW devices on normal 42-LT, and its applicability is discussed.