Patent EP0605884A1 successfully refreshed from Google Patents.
EP0605884A1
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EP
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IIDT type surface acoustic wave device
Assignee: Murata Manufacturing Co Ltd
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Filing: 1993-12-28
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Granted: —
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Expires: 2013-12-28
Abstract
Abstract An IIDT type surface acoustic wave filter (41) comprising a piezoelectric substrate and at least three IDTs (44 to 46) which are arranged on a surface of the piezoelectric substrate along the direction of surface wave propagation, the IDT (44) being inverted in phase with respect to the other IDT (46) while these IDTs (44) and (46) being connected in series to each other through the ground potential, thereby balancing inputs or outputs.
Inventors
- 👤 Takaharu Kawakatsu
- 👤 Yutaka Tada
- 👤 Hideharu Ieki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 01:40
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/64; H03H9/6423; H03H9/6433; H03H9/6436; H03H9/0023; H03H9/0028; H03H9/0033; H03H9/0038; H03H9/0042; H03H9/0047; H03H9/0052; H03H9/0057; H03H9/0061; H03H9/02; H03H9/125; H03H9/145; H03H9/14544; H03H9/1455
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
141 words
An IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers being formed on a surface of said piezoelectric substrate along the direction of surface wave propagation and each provided with a pair of comb electrodes having plural electrode fingers interdigitating with each other, said interdigital transducers alternately serving as an input (or output) or output (or input) interdigital transducer along the direction of surface wave propagation, each said interdigital transducer belonging to a first group being inverted in phase with respect to each said interdigital transducer belonging to a second group upon division of said input or output interdigital transducers being provided in an even number into two groups along the center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
Claim 2
Dependent Claim
86 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein that of said comb electrodes being connected to an input/output end of each said interdigital transducer belonging to said first group is displaced by one electrode finger pitch with respect to that connected to an input/output end of each said interdigital transducer belonging to said second group, each said interdigital transducer belonging to said first group being thereby inverted in phase with respect to each said interdigital transducer belonging to said second group.
Claim 3
Dependent Claim
78 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein that of said comb electrodes being combined with that being connected to an input/output end of each said interdigital transducer belonging to said first group is provided with a dummy electrode finger or dummy fingers of an odd number, each said interdigital transducer belonging to said first group being thereby inverted in phase with respect to each said interdigital transducer belonging to said second group.
Claim 4
Dependent Claim
39 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein each said interdigital transducer belonging to said first group is connected in series to each said interdigital transducer belonging to said group through the ground potential.
Claim 5
Dependent Claim
30 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein balanced input/output ends are arranged on one side of said region provided with all said interdigital transducers.
Claim 6
Dependent Claim
34 words
An IIDT type surface acoustic wave device in accordance with claim 1, further comprising a pair of reflectors being provided on both sides of a region provided with said at least three interdigital transducers.
Claim 7
Dependent Claim
86 words
An IIDT type multi-stage surface acoustic wave device comprising a piezoelectric substrate and at least two stages of IIDT type surface acoustic wave devices being formed on said piezoelectric substrate and successively connected with each other, each said IIDT type surface acoustic wave device of at least either an input or output stage being formed by an IIDT type surface acoustic wave device in accordance with claim 1, those of said interdigital transducers being provided in an even number serving as input and/or output interdigital transducers.
Claim 8
Dependent Claim
87 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein that of said comb electrodes being connected to an input/output end of each said interdigital transducer belonging to said first group is displaced by one electrode finger pitch with respect to that connected to an input/output end of each said interdigital transducer belonging to said second group, each said interdigital transducer belonging to said first group being thereby inverted in phase with respect to each said interdigital transducer belonging to said second group.
Claim 9
Dependent Claim
79 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein that of said comb electrodes being combined with that being connected to an input/output end of each said interdigital transducer belonging to said first group is provided with a dummy electrode finger or dummy fingers of an odd number, each said interdigital transducer belonging to said first group being thereby inverted in phase with respect to each said interdigital transducer belonging to said second group.
Claim 10
Dependent Claim
41 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein each said interdigital transducer belonging to said first group is connected in series to each said interdigital transducer belonging to said second group through the ground potential.
Claim 11
Dependent Claim
31 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein balanced input/output ends are arranged on one side of said region provided with all said interdigital transducers.
Claim 12
Dependent Claim
35 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, further comprising a pair of reflectors being provided on both sides of a region provided with said at least three interdigital transducers.
References Cited (Backward Citations)
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