| 摘要 |
PURPOSE: A surface acoustic wave filter is provided to be capable of improving an attenuation property of the filter by extending a ground region of the filter effectively so as to prevent a noise. CONSTITUTION: A piezoelectric substrate(20) is installed in a package(10) where a connection part to be connected with the outside is formed. The piezoelectric substrate(20) is vibrated when an electric energy is converted into a mechanical energy according to applying of an electric field. An input/output IDT(30) is formed at the substrate(20) in a pattern format and passes a signal of a desired frequency band when a signal is received from the exterior. A ground part(40) is formed around the input/output IDT(30) and performs a ground operation so that a noise is prevented. An extended ground part(60) is formed between the ground part(40) and the substrate(20) so that a region of the ground part(40) is extended. |
