US3777274A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic interaction guide structure for acoustic surface waves
Assignee: United States Department of the Navy
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Filing: 1972-01-18
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Granted: 1973-12-04
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Expires: 1992-01-18
Abstract
Abstract Acoustic surface waves are produced in a lossy piezoelectric material and are guided therealong due to the interaction between the acoustic waves and a drift electron flow established in an adjacent semiconductor matrial; i.e., the drift electrons impart energy sufficient to sustain propagation of the acoustic surface waves only in the desired direction defined by the drift electron path or channel.
Inventors
- 👤 D Abraham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:00
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/0296; H03H9/02976; H03F; H03F13/00; H03H9/02637; H03H9/02779; H03H9/02787; H03H9/46; H03H9/64; H03H9/6403
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
267 words
A guide structure for acoustic surface waves comprising, in combination, a polycrystalline piezoelectric film member having a power loss per unit length Alpha expressed as Beta max. > Alpha >Lne (So/N) 1/d where, Beta max. maximum or saturation interaction gain, d minimum separation between adjacent guide paths, So/N minimum acceptable signal to noise power ratio, and e base of the natural logarithm, a member disposed adjacent said lossy piezoelectric member and forming a drift electron conduction channel, a drift field voltage source means connected across the ends of said conduction channel to create a drift electron flow along said conduction channel, said drift electron flow defining a propagation path within said piezoelectric member solely along which said drift electron flow will interact with and impart energy to sustain the propagation of acoustic surface waves within said piezoelectric member, said polycrystalline piezoelectric film member being substantially isotropic over the width of said propagation path, said acoustic surface waves being attenuated within said piezoelectric member, except along said propagation path, due to the lossy nature of said piezoelectric member, first transducer means connected to said lossy piezoelectric member adjacent said conduction channel for establishing acoustic surface waves which propagate within said lossy piezoelectric member only along the propagation path defined by and in the direction of said drift electron flow, and second transducer means connected to said lossy piezoelectric member adjacent said conduction channel and spaced from said first transducer means in the direction of propagation of said acoustic surface waves for receiving said acoustic surface waves after propagation along the propagation path defined by said drift electron flow.
Claim 2
Dependent Claim
267 words
A guide structure for acoustic surface waves comprising, in combination, a polycrystalline piezoelectric film member having a power loss per unit length Alpha expressed as Beta max. > Alpha >Lne (So/N) 1/d where, Beta max. maximum or saturation interaction gain, d minimum separation between adjacent guide paths, So/N minimum acceptable signal to noise power ratio, and e base of the natural logarithm, a member disposed adjacent said lossy piezoelectric member and forming a drift electron conduction channel, a drift field voltage source means connected across the ends of said conduction channel to create a drift electron flow along said conduction channel, said drift electron flow defining a propagation path within said piezoelectric member solely along which said drift electron flow will interact with and impart energy to sustain the propagation of acoustic surface waves within said piezoelectric member, said polycrystalline piezoelectric film member being substantially isotropic over the width of said propagation path, said acoustic surface waves being attenuated within said piezoelectric member, except along said propagation path, due to the lossy nature of said piezoelectric member, first transducer means connected to said lossy piezoelectric member adjacent said conduction channel for establishing acoustic surface waves which propagate within said lossy piezoelectric member only along the propagation path defined by and in the direction of said drift electron flow, and second transducer means connected to said lossy piezoelectric member adjacent said conduction channel and spaced from said first transducer means in the direction of propagation of said acoustic surface waves for receiving said acoustic surface waves after propagation along the propagation path defined by said drift electron flow.
Claim 3
Dependent Claim
22 words
The guide structure specified in claim 1 wherein said lossy piezoelectric member is in the form of a substantially flat thin film.
Claim 4
Dependent Claim
23 words
The guide structure specified in claim 1 wherein said drift electron conduction channel member is a semiconductor material characterized by high electron mobility.
Claim 5
Dependent Claim
26 words
The guide structure specified in claim 2 further including a high resistivity substrate to support said lossy piezoelectric film and said drift electron conduction channel member.
Claim 6
Dependent Claim
39 words
The guide structure specified in claim 4 wherein said drift electron conduction channel member is a semiconductor layer epitaxially mounted on said substrate and said lossy piezoelectric thin film is deposited on said substrate overlying said epitaxial semiconductor layer.
Claim 7
Dependent Claim
39 words
The guide structure specified in claim 5 wherein said high resistivity substrate is formed of chromium doped gallium arsenide, said epitaxial semiconductor layer is formed of gallium arsenide and said lossy piezoelectric thin film is formed of aluminum nitride.
Claim 8
Dependent Claim
53 words
The guide structure specified in claim 1 wherein said drift electron conduction channel member forms a network of interconnected drift electron conduction channels and wherein said drift field voltage source means includes means for selectively creating a drift electron flow along a predetermined route through said network of interconnected drift electron conduction channels.
Claim 9
Dependent Claim
29 words
The guide structure specified in claim 1 further including means for reversing the polarity of energization of said drift electron conduction channel member by said drift voltage source means.
Claim 10
Dependent Claim
30 words
The guide structure specified in claim 7 further including means for reversing the polarity of energization of said drift electron conduction channel member by said drift field voltage source means.
Claim 11
Independent Claim
139 words
A method of guiding acoustic surface waves comprising the steps of, establishing said acoustic surface waves in a polycrystalline piezoelectric film mEmber having a power loss per unit length Alpha expressed as Beta max. > Alpha >Lne (So/N1/d where, Beta max. maximum or saturation interaction gain, d minimum separation between adjacent guide paths, So/N minimum acceptable signal to noise power ratio, and e base of the natural logarithm, and creating adjacent said polycrystalline piezoelectric film member a drift electron flow along a predetermined channel effective to define a propagation path within said piezoelectric member solely along which said drift electron flow will interact with and impart energy to sustain the propagation of said acoustic surface waves in the direction of said drift electron flow, said polycrystalline piezoelectric film member being substantially isotropic over the width of said propagation path.
Claim 12
Independent Claim
139 words
A method of guiding acoustic surface waves comprising the steps of, establishing said acoustic surface waves in a polycrystalline piezoelectric film mEmber having a power loss per unit length Alpha expressed as Beta max. > Alpha >Lne (So/N1/d where, Beta max. maximum or saturation interaction gain, d minimum separation between adjacent guide paths, So/N minimum acceptable signal to noise power ratio, and e base of the natural logarithm, and creating adjacent said polycrystalline piezoelectric film member a drift electron flow along a predetermined channel effective to define a propagation path within said piezoelectric member solely along which said drift electron flow will interact with and impart energy to sustain the propagation of said acoustic surface waves in the direction of said drift electron flow, said polycrystalline piezoelectric film member being substantially isotropic over the width of said propagation path.
Claim 13
Dependent Claim
45 words
The method specified in claim 10 wherein the step of creating a drift electron flow along a predetermined channel is accomplished by selectively connecting a drift field voltage source across the ends of a selected path through a network of interconnected drift electron conduction channels.
Claim 14
Dependent Claim
23 words
The method specified in claim 10 further including the step of selectively controlling the direction of drift electron flow along said predetermined channel.
References Cited (Backward Citations)
US3406358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |