Patent US5141515A successfully refreshed from Google Patents.
US4480324A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant beamwidth frequency independent acoustic antenna
Assignee: United States Department of the Navy
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Filing: 1983-04-11
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Granted: 1984-10-30
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Expires: 2003-04-11
Abstract
Abstract A frequency independent log periodic acoustic device is utilized for the transmission or reception of underwater sound. A key element of the device is a particularly shaped plate or diaphragm, called a filter plate, made of stainless steel or other material having suitable acoustic properties. The filter plate on being placed in front of any plane wave receiving or transmitting transducer acts automatically to make the beamwidth of the diffraction pattern of the combined device constant, regardless of frequency. This is achieved by automatically making the effective aperture diameter of the filter plate-transducer combination a constant multiple of the acoustic wavelength of the sound in the underwater medium. When used in conjunction with a scannable transducer such as an acoustic lens and the retina device the filter plate produces a directional, scannable, substantially constant beamwidth diffraction pattern for radiation or reception of underwater acoustic signals. The thickness of the plate at both its center and outer operative diameter are determined by the wavelengths of the respective highest and lowest frequencies to be utilized.
Inventors
- 👤 Robert L. Sternberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:35
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/02; G10K11/04; G10K11/18
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
An acoustic device adapted for use in an underwater system comprising a filter plate of variable thickness having means for receiving signals, said filter plate having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its surface area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point.
Claim 2
Dependent Claim
94 words
An acoustic device adapted for use in an underwater system comprising a filter plate of variable thickness having means for receiving signals, said filter plate having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its surface area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point.
Claim 3
Dependent Claim
20 words
An acoustic device according to claim 1 wherein the thickness of said filter plate along its axis is substantially zero.
Claim 4
Dependent Claim
126 words
An acoustic receiver comprising: acoustic means for preforming a directional receiving beam with a frequency independent beamwidth, said acoustic means including a filter plate of variable thickness having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its surface area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point; and wide band transducer means in signal communication with said acoustic means for converting the acoustic signals in said receiving beam to electrical signals over a wide range of frequencies.
Claim 5
Dependent Claim
126 words
An acoustic receiver comprising: acoustic means for preforming a directional receiving beam with a frequency independent beamwidth, said acoustic means including a filter plate of variable thickness having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its surface area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point; and wide band transducer means in signal communication with said acoustic means for converting the acoustic signals in said receiving beam to electrical signals over a wide range of frequencies.
Claim 6
Dependent Claim
20 words
An acoustic receiver according to claim 3 wherein the thickness of said filter plate along its axis is substantially zero.
Claim 7
Dependent Claim
168 words
A scannable acoustic receiver comprising: acoustic means for preforming frequency independent directional scannable beams, said beams for receiving acoustic signals, said acoustic means including a filter plate of variable thickness having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point; wide angle focusing means in signal communication with said acoustic means for focusing said received acoustic signals arriving at various angles to the axis of the receiver; and wide band transducing means in signal communication with said acoustic means and said focusing means for converting received and focused acoustic signals to electrical signals, said transducing means including a retina of separate transducing elements each corresponding to a different receiving direction.
Claim 8
Dependent Claim
168 words
A scannable acoustic receiver comprising: acoustic means for preforming frequency independent directional scannable beams, said beams for receiving acoustic signals, said acoustic means including a filter plate of variable thickness having first and second opposing surfaces, said filter plate having said first surface which is substantially planar and said second surface which is substantially right circular conical with the axis of said conical surface perpendicular to said first surface, the thickness of the plate at each point over its area being not more than one-twentieth of the wavelength of the acoustic signals to be transmitted at that point; wide angle focusing means in signal communication with said acoustic means for focusing said received acoustic signals arriving at various angles to the axis of the receiver; and wide band transducing means in signal communication with said acoustic means and said focusing means for converting received and focused acoustic signals to electrical signals, said transducing means including a retina of separate transducing elements each corresponding to a different receiving direction.
Claim 9
Dependent Claim
21 words
A scannable acoustic receiver according to claim 5 wherein the thickness of said filter plate along its axis is substantially zero.
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) | 1987-10-30 | 1988-04-30 | 1988-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-30 | 1992-04-30 | 1992-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-30 | 1996-04-30 | 1996-10-30 | $7700.00 | Window Closed / Lapsed |