发明名称 |
End-surface reflection type surface acoustic wave filter |
摘要 |
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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申请公布号 |
US6784764(B2) |
申请公布日期 |
2004.08.31 |
申请号 |
US20020218017 |
申请日期 |
2002.08.14 |
申请人 |
MURATA MANUFACTURING CO., LTD. |
发明人 |
KADOTA MICHIO;HORIUCHI HIDEYA;AGO JUNYA;NAKAO TAKESHI;KURATANI YASUHIRO |
分类号 |
H03H9/145;H03H9/02;H03H9/25;H03H9/64;(IPC1-7):H03H9/00 |
主分类号 |
H03H9/145 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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