| 摘要 |
PURPOSE: A package structure of a surface acoustic wave(SAW) filter improves SAW filter characteristic by reducing the influence of electromagnetic feed-through. CONSTITUTION: A package structure of a surface acoustic wave filter(10) includes a base section(30), a frame(31) whose surface is covered with a metal extended in the direction perpendicular to the base section along an edge of the base section. Many metal pads are formed to the outer part of the base section. A surface acoustic wave filter includes an input terminal IDT(12) and an output terminal IDT(13) which are respectively formed to the both sides of one side surface of piezoelectric substance. The surface acoustic wave filter is attached on a ground part(33) as of a metal plating layer. A cutoff rod is positioned to the input terminal IDT and the output terminal IDT. A cover seals the surface acoustic wave filter. A metal plating layer of the ground part corresponding to a bottom of the cutoff rod includes a cutting part(36) being cut by two stages, and a metal surface(37) which is formed by the cutting part and is electrically divided from the metal plating layer. Thereby, the package structure of a surface acoustic wave filter considerably reduces electromagnetic feed-through, enlarges attenuation in a stop band of the filter, reduces ripples generated in a pass band, and realizes a superior SAW filter.
|
