Modified Mason model for bulk acoustic wave resonators

Accurate modeling of a bulk acoustic wave resonator frequency response is limited by the inability of the current 1-D models to simulate certain parasitic modes excited in realistic 3-D structures. A simple technique is proposed to simulate such parasitic modes by employing the 1-D Mason Model of a resonator and a coupling term between the fundamental mode and those parasitic modes. This Modified Mason Model allows accurate simulation of resonators with arbitrary impedance and arbitrary resonating frequency. Finally, the model's prediction is compared with the on-wafer measurement of a ladder-type filter composed of several resonators.