PZT based bulk acoustic wave RF filters

Analytical solutions of the wave equation for the electrode-piezoelectric-electrode sandwich structure in film bulk acoustic resonators (FBARs) are presented. The impedance for PZT based FBAR is derived utilizing proper boundary conditions and their material parameters. A novel method to adjust the resonant frequency is proposed corresponding to the process feasibility and material properties. Ferroelectric-based RF filters composed of FBARs are designed.