Phenomenological Circuit Modeling of Ferroelectric-Driven Bulk Acoustic Wave Resonators

A nonlinear circuit model has been developed to model electrostriction in thin-film ferroelectric bulk acoustic wave (BAW) resonators. This new model is based on nonlinear coupling relations among strain, stress, electric field, and polarization, derived from the Landau–Devonshire theory. The coupling relations and the mechanical vibrations are then represented as lumped circuit elements using an improved approximation procedure along with an enhanced model for dielectric loss. The response from the simulation is compared with the measurement results obtained for a barium strontium titanate (BST) thin-film bulk acoustic resonator (FBAR) at different dc bias levels. The improved approximation procedure enables one to achieve accurate simulation results with reduced circuit model complexity.