US3845418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic surface wave device with reduced rf feedthrough
Assignee: Raytheon Co
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Filing: 1974-01-02
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Granted: 1974-10-29
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Expires: 1994-01-02
Abstract
Abstract An acoustic surface wave device of the type having a launching transducer and a receiving transducer disposed in relatively close proximity on a substrate of piezoelectric material wherein the dynamic range of the device is increased by the reduction and elimination of spurious responses resulting from undesired, RF feedthrough signals due to direct coupling between the transducers, the device incorporating a radiating element or structure disposed in the vicinity of the launching transducer and fed RF input signal energy in phase opposition to ''''buck'''' out the leakage component at the receiving transducer because the bucking signal energy generated by the radiating element is seen at the receiving transducer to be of equal magnitude and out of phase with the directly coupled leakage component thereat.
Inventors
- 👤 R Weglein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:09
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02818; H03H9/02874
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
An acoustic surface wave device, comprising: a substrate of piezoelectric material capable of propagating acoustic surface wave energy; transducer means including at least a launching transducer for converting an electrical input signal into acoustic surface waves propagating along said substrate, and including an associated receiving transducer for converting said acoustic surface waves incident thereon into electrical signals with a delay essentially determined by the propagating velocity characteristic of the substrate material and by the distance between said launching and receiving transducers, said distance being sufficiently small that a direct r.f. feedthrough signal coupling exists between said transducers; and bucking means including a phase shifting electrical arrangement coupled to the electrical input of said launching transducer and also including a conductive bucking electrode structure disposed adjacent said launching transducer and coupled to said electrical arrangement for coupling directly to said receiving transducer a bucking signal of equal magnitude and opposite phase than that of said direct r.f. feedthrough signal.
Claim 2
Dependent Claim
158 words
An acoustic surface wave device, comprising: a substrate of piezoelectric material capable of propagating acoustic surface wave energy; transducer means including at least a launching transducer for converting an electrical input signal into acoustic surface waves propagating along said substrate, and including an associated receiving transducer for converting said acoustic surface waves incident thereon into electrical signals with a delay essentially determined by the propagating velocity characteristic of the substrate material and by the distance between said launching and receiving transducers, said distance being sufficiently small that a direct r.f. feedthrough signal coupling exists between said transducers; and bucking means including a phase shifting electrical arrangement coupled to the electrical input of said launching transducer and also including a conductive bucking electrode structure disposed adjacent said launching transducer and coupled to said electrical arrangement for coupling directly to said receiving transducer a bucking signal of equal magnitude and opposite phase than that of said direct r.f. feedthrough signal.
Claim 3
Dependent Claim
34 words
The device according to claim 1, wherein said phase shifting electrical arrangement includes a phase shift network and an attenuator coupled between said electrical input of said launching transducer and said bucking electrode structure.
Claim 4
Dependent Claim
16 words
The device according to claim 2, wherein said phase shift network and said attenuator are adjustable.
Claim 5
Dependent Claim
27 words
The device according to claim 1, wherein said bucking electrode structure is an elongated conductive strip disposed on said substrate surface between said launching and receiving transducers.
Claim 6
Dependent Claim
27 words
The device according to claim 1, wherein said bucking electrode structure is a hollow rectangular conductive strip disposed on said substrate surface and surrounding said launching transducer.
Claim 7
Dependent Claim
27 words
The device according to claim 1, wherein said bucking electrode structure is an elongated conductive strip disposed on said substrate at one side of said launching transducer.
Claim 8
Dependent Claim
26 words
The device according to claim 1, wherein said bucking electrode structure is a relatively wide elongated conductive strip disposed in insulative relationship above said substrate surface.
Claim 9
Dependent Claim
40 words
The device according to claim 1, wherein said phase shifting electrical arrangement includes a balanced center tapped coil across half of which is coupled said launching transducer and across the other half of which is coupled said bucking electrode structure.
References Cited (Backward Citations)
US3573673A
Cited
US3723919A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |