SURFACE ACOUSTIC WAVE FILTER DEVICE - MURATA MANUFACTURING CO

Title:

SURFACE ACOUSTIC WAVE FILTER DEVICE

Document Type and Number:

WIPO Patent Application WO/2008/068951

Kind Code:

A1

Abstract:

A cascade connection type of longitudinally coupled resonator type surface acoustic wave filter device having an interstage capacitor is reduced in size. The surface acoustic wave filter device (1) is configured as follows. First and second longitudinally coupled resonator type surface acoustic wave filters (3, 4) are formed on a piezoelectric substrate (2). One end of a first IDT (3a) at the center of the first longitudinally coupled resonator type surface acoustic wave filter is connected to a first unbalanced terminal (5), and one end of a first IDT (4a) at the center of the second longitudinally coupled resonator type surface acoustic wave filter is connected to a second unbalanced terminal (6). The signal terminals of second IDTs (3b, 4b) of the first and second longitudinally coupled resonator type surface acoustic wave filters (3, 4) are connected through a first signal line (9) to each other. The signal terminals of third IDTs (3c, 4c) are connected through a second signal line (10) to each other. A capacitor (11) is connected between the first and second signal lines (9, 10).

Inventors:

WATANABE NORIO (JP)

Application Number:

PCT/JP2007/069445

Publication Date:

June 12, 2008

Filing Date:

October 04, 2007

Export Citation:

Click for automatic bibliography generation Help

Assignee:

MURATA MANUFACTURING CO (JP)
WATANABE NORIO (JP)

International Classes:

H03H9/64; H03H9/145

Foreign References:

JP2003124776A	2003-04-25
JP2003338724A	2003-11-28
JP2000077967A	2000-03-14
JPH0774588A	1995-03-17