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US 7,057,476 B2Granted
Noise suppression method for wave filter
AssigneeIndustrial Technology Research Institute
InventorKeh-Long Hwu
Life of this patent
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AssigneeIndustrial Technology Research Institute
InventorKeh-Long Hwu
Estimating the term…
A noise suppression method of a wave filter used to eliminate standing wave signal interferences in the acoustic wave filter consisted by a plurality of film bulk acoustic resonators (FBARs). The method is to provide a plurality of scatterers in the structured consisted by the FBARs, thereby creating an band-gap structure due to the material characteristics difference, which consequently generates a destructive interfering effect to the transverse higher harmonics vibration within a specific operating frequency range, and ultimately decreases or even eliminates any parasitic effects. Therefore, within the operation frequency range of this band-gap structure, abnormal signals created by any transverse wave modes cannot exist. In addition, an acoustic shield can be provided by phononic crystal structures between different FBARs, thus acoustic shielding any mutual interference within the operation frequency range.
A noise suppression method for a wave filter, the wave filter being provided with at least one film bulk acoustic resonator (FBAR), a piezoelectric film being located at the center of the FBAR, the piezoelectric film having an upper surface and a lower surface, said upper and lower surfaces being plated with conductive material to be used as an upper working electrode and a lower working electrode, respectively, wherein a region overlapping the piezoelectric film and the upper and lower working electrodes forms an acoustic resonant cavity, the noise suppression method comprising at least the following steps of:
A noise suppression method for a wave filter, the wave filter being provided with at least one film bulk acoustic resonator (FBAR), a piezoelectric film being located at the center of the FBAR, the piezoelectric film having an upper surface and a lower surface, said upper and lower surfaces being plated with conductive material to be used as upper working electrode and a lower working electrode, respectively, wherein a region overlapping the piezoelectric film and the upper and lower working electrodes forms an acoustic resonant cavity, the noise suppression method comprising at least the following steps of:
A noise suppression method of for a wave filter, the wave filter being provided with at least one film bulk acoustic resonator (FBAR), a piezoelectric film being located at the center of the FBAR, the piezoelectric film having an upper surface and a lower surface, said upper and lower surfaces being plated with conductive material to be used as an upper working electrode and a lower working electrode, respectively, wherein a region overlapping the piezoelectric film and the upper and lower working electrodes forms an acoustic resonant cavity, the noise suppression method comprising at least the following step of:
Dependencies are inferred from the claim text.