US4210883A
Expired / Lapsed
US
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Technique for widening the temperature range of surface acoustic wave reflection array filters
Assignee: Harris Corp
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Filing: 1978-06-27
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Granted: 1980-07-01
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Expires: 1998-06-27
Abstract
Abstract For widening the temperature range of a reflective array device configured on a substrate having an anisotropic temperature coefficient of delay, such as ST-quartz material, so that the signal strength does not decrease appreciably as the temperature of the device is changed over a broad range, the structural shape of the reflective array is configured such that the reflection angles of the discontinuity-creating surface structure vary across the reflecting edges of the discontinuity stripe (e.g. groove or rib) pattern. In one embodiment, the stripe pattern of the grating may be varied so that the reflection angles vary for alternating stripes. In another embodiment, opposite edges of a stripe may be non-parallel so that the reflection angles vary for each stripe. It is also possible to amplitude weight the frequency response characteristic of a grating by controlling the physical structure of the individual stripes of which a grating pattern is formed. The use of a dot array configuration is especially advantageous in this regard since amplitude weighting can be achieved simply by controlling the dot array density of each stripe, implemented in a straightforward manner by suitable design of the grating mask.
Inventors
- 👤 Manhar L. Shah
- 👤 William D. Hunt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:50
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02834; H03H9/02637; H03H9/02653
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
182 words
In a surface acoustic wave device comprising a substrate capable of supporting acoustic waves at a surface thereof, and a reflective array grating formed of a plurality of acoustic wave-reflective elements, the boundaries of which elements create reflective discontinuities along the surface of said substrate, disposed at said surface of said substrate, a boundary of each element defining a respective grating angle relative to a prescribed direction of acoustic propagation, the improvement wherein said plurality of elements is comprised of plural sets of said elements, the elements of one of said sets having a discontinuity-creating boundary the grating angle of which differs from the grating angle of a discontinuity-creating boundary of the elements of another of said sets, and wherein the elements of said sets are interleaved with one another along said prescribed direction of acoustic propagation, so that an acoustic wave traveling along said prescribed direction encounters the boundaries of differing grating angles of each of the elements of said plural sets and thereafter repeatedly encounters the boundaries of different grating angles of each of the elements of said plural sets.
Claim 2
Dependent Claim
182 words
In a surface acoustic wave device comprising a substrate capable of supporting acoustic waves at a surface thereof, and a reflective array grating formed of a plurality of acoustic wave-reflective elements, the boundaries of which elements create reflective discontinuities along the surface of said substrate, disposed at said surface of said substrate, a boundary of each element defining a respective grating angle relative to a prescribed direction of acoustic propagation, the improvement wherein said plurality of elements is comprised of plural sets of said elements, the elements of one of said sets having a discontinuity-creating boundary the grating angle of which differs from the grating angle of a discontinuity-creating boundary of the elements of another of said sets, and wherein the elements of said sets are interleaved with one another along said prescribed direction of acoustic propagation, so that an acoustic wave traveling along said prescribed direction encounters the boundaries of differing grating angles of each of the elements of said plural sets and thereafter repeatedly encounters the boundaries of different grating angles of each of the elements of said plural sets.
Claim 3
Dependent Claim
21 words
The improvement according to claim 1, wherein the adjacent grating angle-defining boundaries of an individual element are parallel with each other.
Claim 4
Dependent Claim
21 words
The improvement according to claim 1, wherein the adjacent grating angle-defining boundaries of an individual element are non-parallel with each other.
Claim 5
Dependent Claim
23 words
The improvement according to claim 1, wherein the adjacent grating angle-defining boundaries of adjacent ones of said elements are parallel with each other.
Claim 6
Dependent Claim
23 words
The improvement according to claim 1, wherein the adjacent grating angle-defining boundaries of adjacent ones of said elements are non-parallel with each other.
Claim 7
Dependent Claim
21 words
The improvement according to claim 1, wherein said elements are configured as respective grooves formed in said surface of said substrate.
Claim 8
Dependent Claim
25 words
The improvement according to claim 1, wherein said elements are configured as layers of acoustic wave-reflective discontinuity-creating material formed on said surface of said substrate.
Claim 9
Dependent Claim
18 words
The improvement according to claim 7, wherein each element is formed of a continuous layer of said material.
Claim 10
Dependent Claim
23 words
The improvement according to claim 7, wherein each element is formed of a distributed multiplicity of discrete dot-like scatterers formed of said material.
Claim 11
Dependent Claim
16 words
The improvement according to claim 7, wherein said layers of material are formed of metallic layers.
Claim 12
Dependent Claim
13 words
The improvement according to claim 1, wherein said substrate is made of ST-quartz.
Claim 13
Dependent Claim
17 words
The improvement according to claim 6, wherein each of said grooves has first and second parallel sides.
Claim 14
Dependent Claim
29 words
The improvement according to claim 7, wherein each of said layers of material has first and second sides oriented at respectively different angles relative to said direction of propagation.
Claim 15
Dependent Claim
45 words
The improvement according to claim 9, wherein the distributed multiplicity of discrete dot-like scatterers of which each element is formed are confined within an areal pattern having a pair of opposite sides that are oriented at respectively different angles relative to said direction of propagation.
Claim 16
Dependent Claim
36 words
The improvement according to claim 1, wherein the structural configurations of each of said elements is such that the frequency response of said array is amplitude weighted along said grating in the acoustic wave propagation direction.
Claim 17
Dependent Claim
27 words
The improvement according to claim 1, further comprising an input transducer for launching surface acoustic waves in said prescribed propagation direction on said surface of said substrate.
Claim 18
Dependent Claim
20 words
The improvement according to claim 16, further comprising an output transducer for receiving acoustic waves reflected by reflective array grating.
Claim 19
Dependent Claim
36 words
The improvement according to claim 9, wherein the distribution of said multiplicity of discrete dot-like scatterers of material is such as to cause the frequency response of said array to be amplitude weighted along said grating.
Claim 20
Dependent Claim
21 words
The improvement according to claim 14, wherein said dot-like scatterers are randomly distributed along the opposite sides of said areal pattern.
Claim 21
Dependent Claim
212 words
In a surface acoustic wave device comprising a substrate capable of supporting acoustic waves at a surface thereof, and a reflective array grating formed of a plurality of acoustic wave-reflective elements, the boundaries of which elements create reflective discontinuities along the surface of said substrate, disposed at said surface of said substrate, a boundary of each element defining a respective grating angle relative to a prescribed direction of acoustic propagation, a method of flattening the signal loss characteristic of said array relative to changes in temperature comprising: orienting said elements to define relatively different interleaved grating angles among plural ones of said elements by arranging said plurality of elements as plural sets of said elements, the elements of one of said sets having a discontinuity-creating boundary, the grating angle of which differs from the grating angle of a discontinuity-creating boundary of the elements of another of said sets, and wherein the elements of said sets are interleaved with one another along said prescribed direction of acoustic propagation, so that an acoustic wave traveling along said prescribed direction encounters the boundaries of differing grating angles of each of the elements of said plural sets and thereafter repeatedly encounters the boundaries of differing grating angles of each of the elements of said plural sets.
Claim 22
Dependent Claim
212 words
In a surface acoustic wave device comprising a substrate capable of supporting acoustic waves at a surface thereof, and a reflective array grating formed of a plurality of acoustic wave-reflective elements, the boundaries of which elements create reflective discontinuities along the surface of said substrate, disposed at said surface of said substrate, a boundary of each element defining a respective grating angle relative to a prescribed direction of acoustic propagation, a method of flattening the signal loss characteristic of said array relative to changes in temperature comprising: orienting said elements to define relatively different interleaved grating angles among plural ones of said elements by arranging said plurality of elements as plural sets of said elements, the elements of one of said sets having a discontinuity-creating boundary, the grating angle of which differs from the grating angle of a discontinuity-creating boundary of the elements of another of said sets, and wherein the elements of said sets are interleaved with one another along said prescribed direction of acoustic propagation, so that an acoustic wave traveling along said prescribed direction encounters the boundaries of differing grating angles of each of the elements of said plural sets and thereafter repeatedly encounters the boundaries of differing grating angles of each of the elements of said plural sets.
Claim 23
Dependent Claim
21 words
The method according to claim 20, wherein the adjacent grating angle-defining boundaries of an individual element are parallel with each other.
Claim 24
Dependent Claim
21 words
The method according to claim 20, wherein the adjacent grating angle-defining boundaries of an individual element are non-parallel with each other.
Claim 25
Dependent Claim
23 words
The method according to claim 20, wherein the adjacent grating angle-defining boundaries of adjacent ones of said elements are parallel with each other.
Claim 26
Dependent Claim
23 words
The method according to claim 20, wherein the adjacent grating angle-defining boundaries of adjacent ones of said elements are non-parallel with each other.
Claim 27
Dependent Claim
21 words
The method according to claim 20, wherein said elements are configured as respective grooves formed in said surface of said substrate.
Claim 28
Dependent Claim
25 words
The method according to claim 20, wherein said elements are configured as layers of acoustic wave-reflective discontinuity-creating material formed on said surface of said substrate.
Claim 29
Dependent Claim
13 words
The method according to claim 20, wherein said substrate is made of ST-quartz.
Claim 30
Dependent Claim
18 words
The method according to claim 26, wherein each element is formed of a continuous layer of said material.
Claim 31
Dependent Claim
23 words
The method according to claim 26, wherein each element is formed of a distributed multiplicity of discrete dot-like scatterers formed of said material.
Claim 32
Dependent Claim
17 words
The method according to claim 25, wherein each of said grooves has first and second parallel sides.
Claim 33
Dependent Claim
29 words
The method according to claim 26, wherein each of said layers of material has first and second sides oriented at respectively different angles relative to said direction of propagation.
Claim 34
Dependent Claim
45 words
The method according to claim 29, wherein the distributed multiplicity of discrete layer segments of which each element is formed are confined within an areal pattern having a pair of opposite sides that are oriented at respectively different angles relative to said direction of propagation.
Claim 35
Dependent Claim
36 words
The method according to claim 29, wherein the distribution of said multiplicity of discrete dot-like scatterers of material is such as to cause the frequency response of said array to be amplitude weighted along said grating.
Claim 36
Dependent Claim
30 words
The method according to claim 20, further comprising the step of configuring each of said elements such that the frequency response of said array is amplitude weighted along said grating.
Claim 37
Dependent Claim
21 words
The method according to claim 32, wherein said dot-like scatterers are randomly distributed along the opposite sides of said areal pattern.
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) | 1983-07-01 | 1983-12-31 | 1984-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-01 | 1987-12-31 | 1988-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-01 | 1991-12-31 | 1992-07-01 | $7700.00 | Window Closed / Lapsed |