Patent ID: 8390397

Claim:
A BAW resonator structure, comprising: a first BAW resonator comprising: a first lower electrode having a first electrical resistance; a first upper electrode having a second electrical resistance; and a first piezoelectric layer disposed between the first lower electrode and the first upper electrode, wherein the first electrical resistance is less than the second electrical resistance; a second BAW resonator comprising: a second lower electrode having the second electrical resistance; a second upper electrode having the first electrical resistance; and a second piezoelectric layer disposed between the second lower electrode and the second upper electrode wherein the first lower electrode and the second upper electrode each have a first acoustic impedance, the first upper electrode and the second lower electrode have a second acoustic impedance, and the first acoustic impedance is less than the second acoustic impedance; and an acoustic coupling layer disposed between the first BAW resonator and the second BAW resonator, wherein the acoustic coupling layer has a third acoustic impedance, which is less than the first acoustic impedance, and a ratio of the second impedance to the third impedance is approximately 4.0 to approximately 100.0.