Patent US4773138A successfully refreshed from Google Patents.
US4773138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing transducer isolation in surface acoustic wave processor
Assignee: United States Department of the Army
•
Filing: 1983-07-27
•
Granted: 1988-09-27
•
Expires: 2003-07-27
Abstract
Abstract An improved manufacturing technique for producing a certain class of Surf Acoustic Wave (SAW) devices, namely those having input and output transducers in close proximity. A much higher manufacturing yield results from eliminating the cutting of a slot in the substrate between input and output transducers as formerly done. This frequently destructive step is replaced by ion-milling of a deep groove between the ports and backfilling with a metal of proper configuration to provide elecromagnetic shielding. The technique produces a new device that is at least equal to the prior art in rejection of unwanted couplings between input and output.
Inventors
- 👤 Arthur D. Ballato
- 👤 Elio A. Mariani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:24
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H9/42; H03H9/44; H03H9/02; H03H9/125; H03H9/145; H03H9/14538; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
163 words
A method of producing a SAW device on a piezoelectric crystal substrate comprising: forming a pair of interdigital transducers on a surface of said substrate at one end thereof and parallel to and equidistant from either side of the centerline of said substrates longest dimension; covering said transducers with a layer of protective material; etching said surface of said substrate with signal processing grooves in conformance with design criteria; etching said surface with a signal isolation groove along said centerline and between said transducers having a length sufficient such that there are no direct paths between said transducers which do not cross said groove, said signal isolation groove having a depth of at least three but less than four acoustic wavelengths of the lowest frequency signal to be processed by said SAW device and a width of approximately one hundred acoustic wavelengths of the lowest frequency signal to be processed by said SAW device; and backfilling said signal isolation groove with a metal.
Claim 2
Independent Claim
163 words
A method of producing a SAW device on a piezoelectric crystal substrate comprising: forming a pair of interdigital transducers on a surface of said substrate at one end thereof and parallel to and equidistant from either side of the centerline of said substrates longest dimension; covering said transducers with a layer of protective material; etching said surface of said substrate with signal processing grooves in conformance with design criteria; etching said surface with a signal isolation groove along said centerline and between said transducers having a length sufficient such that there are no direct paths between said transducers which do not cross said groove, said signal isolation groove having a depth of at least three but less than four acoustic wavelengths of the lowest frequency signal to be processed by said SAW device and a width of approximately one hundred acoustic wavelengths of the lowest frequency signal to be processed by said SAW device; and backfilling said signal isolation groove with a metal.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein said signal isolation groove is backfilled to a depth greater than half.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein said backfilled metal is provided with a circuit connection for grounding.
References Cited (Backward Citations)
US4004254A
Cited
US4097825A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |