US5568002A
Expired / Lapsed
US
⏱️ 0.0 years remaining
IIDT type surface acoustic wave device
Assignee: Murata Manufacturing Co Ltd
•
Filing: 1995-10-10
•
Granted: 1996-10-22
•
Expires: 2015-10-10
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) are 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
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:28
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: 14
Claim 1
Independent Claim
153 words
An IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a 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 each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation, said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a 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
153 words
An IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a 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 each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation, said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
Claim 3
Dependent Claim
85 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein a one of said comb electrodes connected to an end of each said interdigital transducer in said first group is displaced by one electrode finger pitch with respect to a one of said comb electrodes connected to an end of each said interdigital transducer in said second group, each said interdigital transducer in said first group being thereby inverted in phase with respect to each said interdigital transducer in said second group.
Claim 4
Dependent Claim
79 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein a one of said comb electrodes combined with a one of said comb electrodes connected to an end of each said interdigital transducer in said first group is provided with a dummy electrode finger or dummy fingers of an odd number, each said interdigital transducer in said first group being thereby inverted in phase with respect to each said interdigital transducer belong to said second group.
Claim 5
Dependent Claim
36 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein each said interdigital transducer into said first group is connected in series to each said interdigital transducer into said group through ground potential.
Claim 6
Dependent Claim
29 words
An IIDT type surface acoustic wave device in accordance with claim 1, wherein balanced ends are arranged on one side of said region provided with all said interdigital transducers.
Claim 7
Dependent Claim
33 words
An IIDT type surface acoustic wave device in accordance with claim 1, further comprising a pair of reflectors provided on both sides of a region provided with said at least three interdigital transducers.
Claim 8
Dependent Claim
209 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 formed on said piezoelectric substrate and successively connected with each other, each said IIDT type surface acoustic wave device comprising at least one of an input stage and an output stage, each said IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a 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 each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation, said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
Claim 9
Dependent Claim
209 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 formed on said piezoelectric substrate and successively connected with each other, each said IIDT type surface acoustic wave device comprising at least one of an input stage and an output stage, each said IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a 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 each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation, said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
Claim 10
Dependent Claim
86 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein a one of said comb electrodes connected to an end of each said interdigital transducer in said first group is displaced by one electrode finger pitch with respect to a one of said comb electrodes connected to an end of each said interdigital transducer in said second group, each said interdigital transducer in said first group being thereby inverted in phase with respect to each said interdigital transducer in said second group.
Claim 11
Dependent Claim
79 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein a one of said comb electrodes combined with a one of said comb electrodes connected to an end of each said interdigital transducer in said first group is provided with a dummy electrode finger or dummy fingers of an odd number, each said interdigital transducer in said first group being thereby inverted in phase with respect to each said interdigital transducer in said second group.
Claim 12
Dependent Claim
38 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein each said interdigital transducer into said first group is connected in series to each said interdigital transducer into said second group through ground potential.
Claim 13
Dependent Claim
30 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, wherein balanced ends are arranged on one side of said region provided with all said interdigital transducers.
Claim 14
Dependent Claim
34 words
An IIDT type multi-stage surface acoustic wave device in accordance with claim 7, further comprising a pair of reflectors provided on both sides of a region provided with said at least three interdigital transducers.
References Cited (Backward Citations)
US3872410A
Cited
US4044321A
Cited
US4468642A
Cited
US4649357A
Cited
US5010269A
Cited
DE3942148A1
Cited
US5194830A
Cited
US5300902A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-22 | 2000-04-22 | 2000-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-22 | 2004-04-22 | 2004-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-22 | 2008-04-22 | 2008-10-22 | $7700.00 | Window Closed / Lapsed |