Patent US3936774A successfully refreshed from Google Patents.
US3936774A
Expired / Lapsed
US
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High bulk mode rejection surface wave device
Assignee: Texas Instruments Inc
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Filing: 1974-03-14
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Granted: 1976-02-03
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Expires: 1994-03-14
Abstract
Abstract Disclosed is a surface wave device comprising one transducer having its fundamental resonant frequency at a subharmonic of the device operating frequency and a second transducer having its fundamental resonant frequency at the device operating frequency. Both transducers respond to surface waves at the operating frequency. Only the harmonic operated transducer responds to bulk waves at the operating frequency. Thus, signal coupled from one transducer to the other at the operating frequency contains no noise generated by bulk mode coupling.
Inventors
- 👤 Donald Williams Mellon
- 👤 Richard Alan Kempf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:43
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/125; H03H9/145; H03H9/14544; H03H9/14555; G; G10; G10K; G10K11/00; G10K11/36; H03H9/02535; H03H9/02818; H03H9/02866; H03H9/14517
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
124 words
A surface wave device having substantially no bulk mode signal output comprising: a. a substrate for conveying acoustic waves; b. a first transducer having a plurality of electrodes in operative association with the substrate for generating acoustic surface waves, each of said plurality of electrodes having a preselected spacing as to an adjacent electrode at one-half wavelength at a desired operating frequency to reduce substantially the response of the first transducer to bulk waves at the operating frequency; and c. a second transducer having a plurality of electrodes in operative association with the substrate for receiving the first transducer output, each of said plurality of electrodes having preselected spacings from an adjacent electrode at one-half wavelength of a preselected subharmonic of said operating frequency.
Claim 2
Dependent Claim
124 words
A surface wave device having substantially no bulk mode signal output comprising: a. a substrate for conveying acoustic waves; b. a first transducer having a plurality of electrodes in operative association with the substrate for generating acoustic surface waves, each of said plurality of electrodes having a preselected spacing as to an adjacent electrode at one-half wavelength at a desired operating frequency to reduce substantially the response of the first transducer to bulk waves at the operating frequency; and c. a second transducer having a plurality of electrodes in operative association with the substrate for receiving the first transducer output, each of said plurality of electrodes having preselected spacings from an adjacent electrode at one-half wavelength of a preselected subharmonic of said operating frequency.
Claim 3
Dependent Claim
32 words
A surface wave device according to claim 1 wherein said first surface wave transducer is an input surface wave transducer and said second surface wave transducer is an output surface wave transducer.
Claim 4
Dependent Claim
29 words
A surface wave device according to claim 2 wherein said input surface wave transducer comprises electrodes having widths of one quarter of the surface wavelength at the operating frequency.
Claim 5
Dependent Claim
25 words
A surface wave device according to claim 2 wherein said output surface wave transducer has a fundamental resonant frequency of one-third the preselected operating frequency.
Claim 6
Dependent Claim
35 words
A surface wave device according to claim 4 wherein said output surface wave transducer comprises electrodes having widths of four-tenths of the surface wavelengths at one-third the operating frequency, whereby third harmonic response is enhanced.
Claim 7
Independent Claim
92 words
A method for fabricating surface wave devices for substantially rejecting bulk mode signals comprising: a. forming electrodes with preselected spacings for an input surface wave transducer on a piezoelectric substrate for substantially reducing the response including bulk wave signal response of the transducer to a desired harmonic as to a fundamental resonant frequency; and b. forming electrodes with preselected spacings for an output transducer for covering a subharmonic of said fundamental resonant frequency; whereby said transducers cooperate during operation to reject bulk wave signals at the desired harmonic and fundamental resonant frequency.
Claim 8
Independent Claim
92 words
A method for fabricating surface wave devices for substantially rejecting bulk mode signals comprising: a. forming electrodes with preselected spacings for an input surface wave transducer on a piezoelectric substrate for substantially reducing the response including bulk wave signal response of the transducer to a desired harmonic as to a fundamental resonant frequency; and b. forming electrodes with preselected spacings for an output transducer for covering a subharmonic of said fundamental resonant frequency; whereby said transducers cooperate during operation to reject bulk wave signals at the desired harmonic and fundamental resonant frequency.
References Cited (Backward Citations)
US3614463A
Cited
US3742396A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-02-02 | 1979-08-04 | 1980-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-02-02 | 1983-08-04 | 1984-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-02-02 | 1987-08-04 | 1988-02-03 | $7700.00 | Window Closed / Lapsed |