BALANCED TYPE SURFACE ACOUSTIC WAVE FILTER

Title:

BALANCED TYPE SURFACE ACOUSTIC WAVE FILTER

Document Type and Number:

WIPO Patent Application WO/2005/101657

Kind Code:

A1

Abstract:

A means of improving the guaranteed attenuation amount of a cascade-connected unbalanced-balanced double-mode SAW filter is obtained. Two cascade-connected primary-3 double-mode SAW filters are installed adjacently and cascade-connected on a piezoelectric substrate along the propagation direction of a surface wave, one electrode of an IDT disposed at the center of the first double-mode SAW filter is connected to a first port (Port 1), and one electrode of an IDT disposed at the center of the second double-mode SAW filter is connected to a second port (Port 2) and the other electrode to a third port (Port 3), thereby forming an unbalanced-balanced SAW filter; the SAW filter being formed by disposing electrodes in the vicinities of the surroundings of the first port (Port 1) and the third port (Port 3) and by connecting the electrodes to a lead electrode provided on the peripheral edges of the above piezoelectric substrate.

Inventors:

MATSUMOTO SHOZO (JP)

Application Number:

PCT/JP2005/007089

Publication Date:

October 27, 2005

Filing Date:

April 12, 2005

Export Citation:

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Assignee:

TOYO COMMUNICATION EQUIP (JP)
MATSUMOTO SHOZO (JP)

International Classes:

H01L41/09; H01L41/18; H03H9/00; H03H9/02; H03H9/145; H03H9/64; (IPC1-7): H03H9/64; H01L41/09; H01L41/18; H03H9/145

Foreign References:

JP2003060484A	2003-02-28
JP2000312125A	2000-11-07
JP2003218670A	2003-07-31
JP2003204243A	2003-07-18

Other References: