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US4148039A Expired / Lapsed US ⏱️ 0.0 years remaining

Low reflectivity radome

Assignee: Boeing Co
•
Filing: 1978-07-17
•
Granted: 1979-04-03
•
Expires: 1998-07-17
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Abstract

Abstract A low reflectivity radome includes an enclosure wall made of foamed plastic material defining a dielectric constant of about 1.08. Stiffening ribs made from reinforced glass fibers with a dielectric constant of about 4.0 are arranged in an orthogonal manner along planes normal to a tangent to the air-side surface of the radome and at least partially embedded in the enclosure wall for compressive strengthening thereof. Different orthogonal arrangements include the ribs being totally embedded within the enclosure wall, the ribs projecting to uniform or different distances from the inside surface of the enclosure wall or the ribs are arranged in closely, spaced-apart pairs and project from the inside surface of the enclosure wall. When the ribs are totally embedded in the foamed plastic material, the distance between the ends of the ribs and each face surface of the enclosure is selected so that incident microwaves undergo identical phase shifts for all parallel paths through the enclosure wall. The foamed plastic material of the enclosure is coated on the air-side surface with matching conductive paint. On the inside surface, quarter-wave ribs are formed within the dielectric material for interface matching.

Inventors

  • 👤 Clarence D. Lunden

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-27 05:18
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/42; H01Q1/422; H01Q1/424

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 79 words
A low reflectivity radome for a radar antenna, said radome essentially including an enclosure consisting of foamed plastic material, said enclosure defining a smooth air-side facing surface and an oppositely-facing inner surface, said inner surface being defined by parallel projecting ribs integral with said enclosure for phase matching the interface of said inner surface, and a layer of conductive paint covering the air-side facing surface of said enclosure for phase matching the interface at the air-side of the enclosure.
Claim 2
Dependent Claim 79 words
A low reflectivity radome for a radar antenna, said radome essentially including an enclosure consisting of foamed plastic material, said enclosure defining a smooth air-side facing surface and an oppositely-facing inner surface, said inner surface being defined by parallel projecting ribs integral with said enclosure for phase matching the interface of said inner surface, and a layer of conductive paint covering the air-side facing surface of said enclosure for phase matching the interface at the air-side of the enclosure.
Claim 3
Dependent Claim 27 words
The radome according to claim 1 wherein said parallel projecting ribs have a pitch less than or equal to one-half the design wavelength of the electromagnetic waves.
Claim 4
Dependent Claim 18 words
The radome according to claim 1 wherein said ribs project a distance given by the expression ##EQU6## where:
Claim 5
Dependent Claim 8 words
λ o is the design radar wavelength, and
Claim 6
Dependent Claim 8 words
λ o is the design radar wavelength, and
Claim 7
Dependent Claim 14 words
ε f is the dielectric constant of the foamed plastic material of said enclosure.
Claim 8
Dependent Claim 14 words
ε f is the dielectric constant of the foamed plastic material of said enclosure.
Claim 9
Dependent Claim 20 words
The radome according to claim 1 wherein said paint film defines a resistivity given by the following expression ##EQU7## where:
Claim 10
Dependent Claim 5 words
12π = a constant, and
Claim 11
Dependent Claim 5 words
12π = a constant, and
Claim 12
Dependent Claim 9 words
ε f = the dielectric constant of said enclosure.
Claim 13
Dependent Claim 9 words
ε f = the dielectric constant of said enclosure.

References Cited (Backward Citations)

US3780374A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1982-04-02 1982-10-02 1983-04-03 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1986-04-02 1986-10-02 1987-04-03 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1990-04-02 1990-10-02 1991-04-03 $7700.00 Window Closed / Lapsed

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