US5028831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
SAW reflectionless quarter-wavelength transducers
Assignee: CTS Corp
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Filing: 1990-04-04
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Granted: 1991-07-02
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Expires: 2010-04-04
Abstract
Abstract A SAW transducer eliminates mechanical energy reflections by using one-quarter wavelength electrodes spaced at predetermined intervals. Dummy electrodes are shifted one-quarter wavelength to cancel energy reflections in the active electrodes. A pair of dummy electrodes is required for each active set of electrodes (the active set comprises one positive and two negative electrodes).
Inventors
- 👤 Donald C. Malocha
- 👤 David Penunuri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:04
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02842
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
101 words
A surface acoustic wave (SAW) transducer comprising: a substrate; means for generating a SAW comprising a plurality of electrodes each having a first width of one-quarter wave lengths; the means for generating a SAW coupled to the substrate; a plurality of dummy electrodes each having a width equal to the first width; the plurality of dummy electrodes coupled to the substrate in the direction of the SAW propagation; at least one electrode having a second width of one-half wave lengths; and the at least one electrode having a second width coupled to the substrate in the direction of the SAW propagation.
Claim 2
Dependent Claim
101 words
A surface acoustic wave (SAW) transducer comprising: a substrate; means for generating a SAW comprising a plurality of electrodes each having a first width of one-quarter wave lengths; the means for generating a SAW coupled to the substrate; a plurality of dummy electrodes each having a width equal to the first width; the plurality of dummy electrodes coupled to the substrate in the direction of the SAW propagation; at least one electrode having a second width of one-half wave lengths; and the at least one electrode having a second width coupled to the substrate in the direction of the SAW propagation.
Claim 3
Dependent Claim
22 words
A surface acoustic wave (SAW) transducer according to claim 1 wherein the second width is an integer multiple of one-half wave lengths.
Claim 4
Independent Claim
158 words
A method for eliminating energy reflections caused by a propagating surface acoustic wave (SAW) generated within a SAW transducer as the SAW encounters transducer electrodes, the SAW having a direction of propagation through a SAW device substrate, the method comprising the steps of: coupling to the substrate along the direction of SAW propagation a plurality of dummy electrodes which are not actively generating SAWs, each of the plurality of dummy electrodes having a first width of one-quarter wave lengths; coupling to the substrate at least one electrode having a second width of one-half wave lengths; phase shifting within the at least one electrode energy reflections from the plurality of dummy electrodes equal to and opposite in phase with the energy reflections caused by the propagating SAW; and combining the phase shifted energy reflections with the energy reflections caused by the propagating SAW to cancel with the phase shifted energy reflections and the reflections caused by the propagating SAW.
Claim 5
Independent Claim
158 words
A method for eliminating energy reflections caused by a propagating surface acoustic wave (SAW) generated within a SAW transducer as the SAW encounters transducer electrodes, the SAW having a direction of propagation through a SAW device substrate, the method comprising the steps of: coupling to the substrate along the direction of SAW propagation a plurality of dummy electrodes which are not actively generating SAWs, each of the plurality of dummy electrodes having a first width of one-quarter wave lengths; coupling to the substrate at least one electrode having a second width of one-half wave lengths; phase shifting within the at least one electrode energy reflections from the plurality of dummy electrodes equal to and opposite in phase with the energy reflections caused by the propagating SAW; and combining the phase shifted energy reflections with the energy reflections caused by the propagating SAW to cancel with the phase shifted energy reflections and the reflections caused by the propagating SAW.
Claim 6
Dependent Claim
116 words
A surface acoustic wave (SAW) transducer comprising: a substrate; a plurality of unit transducers coupled to the substrate, each of the unit transducers comprising; means for generating a SAW comprising a plurality of electrodes each having a first width of one-quarter wave lengths; the means for generating a SAW coupled to the substrate; a plurality of dummy electrodes each having a width equal to the first width; the plurality of dummy electrodes coupled to the substrate in the direction of the SAW propagation; at least one electrode having a second width of one-half wave lengths; and the at least one electrode having a second width coupled to the substrate in the direction of the SAW propagation.
Claim 7
Dependent Claim
116 words
A surface acoustic wave (SAW) transducer comprising: a substrate; a plurality of unit transducers coupled to the substrate, each of the unit transducers comprising; means for generating a SAW comprising a plurality of electrodes each having a first width of one-quarter wave lengths; the means for generating a SAW coupled to the substrate; a plurality of dummy electrodes each having a width equal to the first width; the plurality of dummy electrodes coupled to the substrate in the direction of the SAW propagation; at least one electrode having a second width of one-half wave lengths; and the at least one electrode having a second width coupled to the substrate in the direction of the SAW propagation.
Claim 8
Dependent Claim
22 words
A surface acoustic wave (SAW) transducer according to claim 4 wherein the second width is an integer multiple of one-half wave lengths.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-07-01 | 1994-12-31 | 1995-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-01 | 1998-12-31 | 1999-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-01 | 2002-12-31 | 2003-07-02 | $7700.00 | Window Closed / Lapsed |