Title:
端面反射型表面波フィルタ
Document Type and Number:
Japanese Patent JP4063000
Kind Code:
B2
Abstract:
An end-surface reflection type surface acoustic wave filter is capable of increasing an attenuation amount outside a pass band while insertion loss characteristics are not seriously deteriorated. The filter is a longitudinally coupled resonator type surface acoustic wave filter using an SH type surface acoustic wave, which has first and second grooves formed in a piezoelectric substrate at the top surface thereof so as to be substantially parallel to each other and spaced from each other by a predetermined distance. In addition, IDTs which are provided between the grooves for defining the longitudinally coupled resonator type surface acoustic wave filter, reflection end-surfaces disposed on side surfaces of the first and the second grooves at the IDT sides, and one of a resin-coating layer and a protective layer made of SiO2, are provided on the top surface of the piezoelectric substrate. The resin-coating layer is arranged to cover at least a region at which the IDTs are located and at least one of the first and the second grooves so as to intrude into one of them, and the protective layer is arranged so as to cover the IDTs.
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Inventors:
Michio Kadota
Hideya Horiuchi
Junya Ago
Takeshi Nakao
Yasuhiro Kuratani
Hideya Horiuchi
Junya Ago
Takeshi Nakao
Yasuhiro Kuratani
Application Number:
JP2002210355A
Publication Date:
March 19, 2008
Filing Date:
July 19, 2002
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
H03H9/145; H03H9/02; H03H9/25; H03H9/64
Domestic Patent References:
| JP4239210A | ||||
| JP2000278091A | ||||
| JP2000232333A | ||||
| JP4239213A |
Attorney, Agent or Firm:
Miyazaki saki main tax