Devices having a tunable acoustic path length and methods for making same

摘要

A tunable acoustic resonator device has a piezoelectric medium as a first thin film layer and a tunable crystal medium as a second thin film layer. The tunable crystal medium has a first acoustic behavior over an operating temperature range under a condition of relatively low applied stress and a second acoustic behavior under a condition of relatively high applied stress. The acoustic behaviors are substantially different and, consequently, the different levels of applied stress are used to tune the acoustic resonator device. Compared with the tunable resonator device consisting of only tunable crystal medium, a device having both the piezoelectric and tunable crystal medium has advantages such as larger inherent bandwidth and less nonlinearity with AC signals. The device also requires a smaller applied stress (i.e. bias voltage) to achieve the required frequency tuning.

主权项

1. An acoustic resonator comprising:
a layer of piezoelectric material, a layer of paraelectric material, wherein the paraelectric material exhibits variable acoustic path length behavior over an operating temperature range under a condition of changing applied stress, wherein the applied stress is a bias applied thereto so as to induce a change in the acoustic path length thereof, and wherein the resonator has a characteristic center frequency which is tunable in response to variations in the bias.