US4516093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface acoustic wave filter
Assignee: Siemens Schweiz AG
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Filing: 1983-07-29
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Granted: 1985-05-07
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Expires: 2003-07-29
Abstract
Abstract A surface acoustic wave (SAW) filter features a ground lead in a transducer that has an aperiodic meander structure. This arrangement permits the self-capacitance and inherent resistance of the transducer to be utilized in forming the RC networks of a phase shifter associated with the transponder.
Inventors
- 👤 Felix Nyffeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:53
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02637; H03H9/02685; H03H9/0274; H03H9/02755; H03H9/125; H03H9/145; H03H9/14597
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
180 words
A surface acoustic wave (SAW) filter formed by a piezoelectric substrate having a substrate surface and at least one transducer disposed on said surface; said transducer comprising, in combination a first plurality of spaced, generally parallel, electrically conductive finger electrodes which are connected to a first terminal and carried by said substrate, and a second plurality of spaced, generally parallel, electrically conductive finger electrodes which are connected to a second terminal and carried by said substrate; the finger electrodes of the first plurality being generally arranged in the intermediate spaces between the finger electrodes of the second plurality; a common terminal for each of said first and second plurality of finger electrodes, said common terminal comprising a strip of electrically conductive material spaced from and meandering through the spaces between said first and second plurality of finger electrodes; said first plurality having several finger electrodes arranged at distances from each other that have values B1, B2, B3, . . . , for which the following condition applies: B1≦B2≦B3≦. . . . where the equal sign is omitted at least once.
Claim 2
Dependent Claim
180 words
A surface acoustic wave (SAW) filter formed by a piezoelectric substrate having a substrate surface and at least one transducer disposed on said surface; said transducer comprising, in combination a first plurality of spaced, generally parallel, electrically conductive finger electrodes which are connected to a first terminal and carried by said substrate, and a second plurality of spaced, generally parallel, electrically conductive finger electrodes which are connected to a second terminal and carried by said substrate; the finger electrodes of the first plurality being generally arranged in the intermediate spaces between the finger electrodes of the second plurality; a common terminal for each of said first and second plurality of finger electrodes, said common terminal comprising a strip of electrically conductive material spaced from and meandering through the spaces between said first and second plurality of finger electrodes; said first plurality having several finger electrodes arranged at distances from each other that have values B1, B2, B3, . . . , for which the following condition applies: B1≦B2≦B3≦. . . . where the equal sign is omitted at least once.
Claim 3
Dependent Claim
23 words
The SAW filter according to claim 1, wherein said piezoelectric transducer is a send transducer for converting electrical energy into acoustic wave energy.
Claim 4
Dependent Claim
23 words
The SAW filter according to claim 1, wherein said piezoelectric transducer is a receive transducer for converting acoustic wave energy into electrical energy.
Claim 5
Dependent Claim
51 words
The SAW filter according to claim 1, wherein there are at least two of said piezoelectric transducers, one of said transducers being a send transducer for converting electrical energy into acoustic wave energy and the other of said transducers being a receive transducer for converting acoustic wave energy into electrical energy.
Claim 6
Dependent Claim
80 words
The SAW filter according to any one of claims 1-4, wherein the values of the distances B1, B2, B3, . . . form at least approximately a series having the following form: B, B, . . . B, 2·B, 2·B, . . . 2·B, 3·B, 3·B, . . . where B is a constant, and wherein a deviation of 0% up to +25% is provided for at least one of the distance values B, 2·B, 3·B, . . . .
Claim 7
Dependent Claim
43 words
The SAW filter according to any one of claims 1-4, wherein there are several finger electrodes for which the distance between a finger electrode of the first plurality and the nearest finger electrode of the second plurality is at least approximately the same.
Claim 8
Dependent Claim
49 words
The SAW filter according to any one of claims 1-4, further comprising a phase shifter connected to one of said terminals for shifting the phase of the transmitted signal, and wherein the self-capacitance and the inherent resistance of the transducer structure form the RC networks of said phase shifter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-06 | 1988-11-05 | 1989-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-06 | 1992-11-05 | 1993-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-06 | 1996-11-05 | 1997-05-07 | $7700.00 | Window Closed / Lapsed |