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Title:
PIEZOELECTRIC FILTER, COMMUNICATION APPARATUS AND METHOD FOR MANUFACTURING THE PIEZOELECTRIC FILTER
Document Type and Number:
Japanese Patent JP2003229743
Kind Code:
A
Abstract:

To provide a piezoelectric filter wherein productivity is high, electrical characteristic is superior and filter characteristic to temperature change is stable, and to provide a communication apparatus and a method for manufacturing the piezoelectric filter.

A piezoelectric resonator part is constituted of an SiO2 thin film 2 on a substrate surface, a piezoelectric thin film 3, a lower electrode 4 and an upper electrode 5. From among a plurality of the piezoelectric resonator parts, the lower electrodes 4 in the piezoelectric resonator parts, where a resonance frequency is set to be comparatively low are made thick, as compared with the lower electrodes in the other piezoelectric resonator parts. For example, the piezoelectric resonators of low resonance frequency are made parallel resonators, and the piezoelectric resonators of high resonance frequency are made series resonators, thereby constituting a ladder-type filter.


Inventors:
TAKEUCHI MASAKI
KAWAMURA HIDEKI
Application Number:
JP2002154255A
Publication Date:
August 15, 2003
Filing Date:
May 28, 2002
Export Citation:
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Assignee:
MURATA MANUFACTURING CO
International Classes:
H01L41/09; H01L41/08; H01L41/18; H01L41/22; H01L41/29; H03H3/02; H03H3/04; H03H9/02; H03H9/17; H03H9/58; H03H9/60; (IPC1-7): H03H9/58; H01L41/08; H01L41/09; H01L41/18; H01L41/22; H03H3/02; H03H9/02; H03H9/17
Attorney, Agent or Firm:
Hisao Komori