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Patent US4162465A successfully refreshed from Google Patents.
US4162465A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface acoustic wave device with reflection suppression
Assignee: University of Illinois Foundation
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Filing: 1977-09-14
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Granted: 1979-07-24
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Expires: 1997-09-14
Abstract
Abstract Applicants discovered that by employing selected transducer geometries, such as unbalanced dual-finger geometries, certain reflections, called "Mechanical electrical loaded" (MEL) reflections, can be generated which tend to cancel reflected waves inherently generated by surface acoustic wave devices. In particular, the disclosure is directed to a transducer for a surface acoustic wave device adapted for coupling to an electrical load and/or source. A pair of interdigitated comb electrodes are formed on an acoustic wave propagating substrate, for example a piezoelectric substrate. Means, such as input or output terminals, are provided for applying an electrical load and/or source across the pair of comb electrodes. Each of the comb electrodes has a plurality of interdigitated electrode fingers. The width of at least some of the adjacent fingers of the electrodes are different and are selected as a function of the impedance of the load and/or source to produce mechanical electrical loaded (MEL) reflections in said substrate which tend to cancel regeneration wave (RW) reflections generated at the transducer in the substrate. In the preferred embodiment of the invention, each of the comb electrodes has at least two adjacent electrode fingers of different widths, and preferably has a plurality of adjacent finger pairs of different widths.
Inventors
- 👤 Bill J. Hunsinger
- 👤 Kentaro Hanma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:11
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/125; H03H9/145; H03H9/14544; H03H9/14552; H03H9/02535; H03H9/02818; H03H9/02842
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
115 words
A transducer for a surface acoustic wave device which includes an acoustic wave propagating substrate, said transducer being adapted to coupling to an electrical load and/or source, comprising: a pair of interdigitated comb electrodes formed on said substrate; means for applying an electrical load and/or source across said pair of comb electrodes; each of said comb electrodes having a plurality of interdigitated electrode fingers, the widths of at least some of the adjacent fingers thereof being different and selected as a function of the impedance of said load and/or source to produce mechanical electrical loaded (MEL) reflections in said substrate which tend to cancel regeneration wave (RW) reflections generated at said transducer in said substrate.
Claim 2
Dependent Claim
115 words
A transducer for a surface acoustic wave device which includes an acoustic wave propagating substrate, said transducer being adapted to coupling to an electrical load and/or source, comprising: a pair of interdigitated comb electrodes formed on said substrate; means for applying an electrical load and/or source across said pair of comb electrodes; each of said comb electrodes having a plurality of interdigitated electrode fingers, the widths of at least some of the adjacent fingers thereof being different and selected as a function of the impedance of said load and/or source to produce mechanical electrical loaded (MEL) reflections in said substrate which tend to cancel regeneration wave (RW) reflections generated at said transducer in said substrate.
Claim 3
Dependent Claim
23 words
The transducer as defined by claim 1 wherein each of said comb electrodes has at least two adjacent electrode fingers of different widths.
Claim 4
Dependent Claim
33 words
The transducer as defined by claim 2 wherein one of said adjacent fingers has a width which is at least twice as great as the width of the other of the adjacent fingers.
Claim 5
Dependent Claim
21 words
The transducer as defined by claim 2 wherein said adjacent fingers have a ratio of widths of about three to one.
Claim 6
Dependent Claim
33 words
The transducer as defined by claim 4 wherein said adjacent fingers have widths of 3/16λ and 1/16λ, respectively, where λ is the acoustic wavelength at the center frequency of operation of said device.
Claim 7
Dependent Claim
23 words
The transducer as defined by claim 1 wherein each of said comb electrodes has a plurality of adjacent finger pairs of different widths.
Claim 8
Dependent Claim
111 words
A surface acoustic wave device adapted for coupling to an electrical load and/or source, comprising: an acoustic wave propagating substrate; a transducer which includes a pair of interdigitated comb electrodes formed on said substrate; means for applying an electrical load and/or source across said pair of comb electrodes; each of said comb electrodes having a plurality of interdigitated electrode fingers, the widths of at least some of the adjacent fingers thereof being different and selected as a function of the impedance of said load and/or source to produce mechanical electrical loaded (MEL) reflections in said substrate which tend to cancel regeneration wave (RW) reflections generated at said transducer in said substrate.
Claim 9
Dependent Claim
111 words
A surface acoustic wave device adapted for coupling to an electrical load and/or source, comprising: an acoustic wave propagating substrate; a transducer which includes a pair of interdigitated comb electrodes formed on said substrate; means for applying an electrical load and/or source across said pair of comb electrodes; each of said comb electrodes having a plurality of interdigitated electrode fingers, the widths of at least some of the adjacent fingers thereof being different and selected as a function of the impedance of said load and/or source to produce mechanical electrical loaded (MEL) reflections in said substrate which tend to cancel regeneration wave (RW) reflections generated at said transducer in said substrate.
Claim 10
Dependent Claim
23 words
The device as defined by claim 7 wherein each of said comb electrodes has at least two adjacent electrode fingers of different widths.
Claim 11
Dependent Claim
33 words
The device as defined by claim 8 wherein one of said adjacent fingers has a width which is at least twice as great as the width of the other of the adjacent fingers.
Claim 12
Dependent Claim
21 words
The device as defined by claim 8 wherein said adjacent fingers have a ratio of widths of about three to one.
Claim 13
Dependent Claim
33 words
The device as defined by claim 10 wherein said adjacent fingers have widths of 3/16λ and 1/16λ, respectively, where λ is the acoustic wavelength at the center frequency of operation of said device.
Claim 14
Dependent Claim
23 words
The device as defined by claim 7 wherein each of said comb electrodes has a plurality of adjacent finger pairs of different widths.
References Cited (Backward Citations)
US3936774A
Cited
US3990023A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-23 | 1983-01-22 | 1983-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-23 | 1987-01-22 | 1987-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-23 | 1991-01-22 | 1991-07-24 | $7700.00 | Window Closed / Lapsed |