Patent ID: 8587391
Filing Date: 2013-11-19
Classification: H03H

Abstract:
1. A bulk acoustic wave (BAW) resonator structure, comprising: a first BAW resonator comprising a first lower electrode, a first upper electrode and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode; a second BAW resonator comprising a second lower electrode, a second upper electrode and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode; and a single-material acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator, the single-material acoustic coupling layer comprising an inhomogeneous acoustic property across a thickness of the acoustic coupling layer, wherein the single-material acoustic coupling layer has an acoustic impedance less than approximately 6.0 MRayls and an acoustic attenuation less than approximately 1000 dB/cm.