Patent ID: 7855618

Claim:
An electrical impedance transformer, comprising: a first film bulk acoustic resonator (FBAR), having a first electrical impedance and a first resonance frequency comprising: a first set of electrodes, having a first acoustic impedance, the first set of electrodes comprising a first material; and a first piezoelectric layer having a first thickness, wherein the first piezoelectric layer is disposed between the first set of electrodes; a second FBAR, having a second electrical impedance and a second resonance frequency, and being disposed over the first FBAR, the second FBAR comprising: a second set of electrodes, having a second acoustic impedance, which differs from the first acoustic impedance, the second set of electrodes comprising a second material; and a second piezoelectric layer having a second thickness, wherein the second piezoelectric layer is disposed between the second set of electrodes, wherein the first thickness is less than the second thickness, and the first material is different than the second material; and a decoupling layer disposed between the first and the second FBARs, wherein the first electrical impedance differs from the second electrical impedance and the first and second resonance frequencies are substantially the same.