US4097796A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for testing radomes
Assignee: Boeing Co
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Filing: 1977-02-18
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Granted: 1978-06-27
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Expires: 1997-02-18
Abstract
Abstract The radio-frequency performance at localized areas of a radome is determined by a method which includes illuminating at normal incidence a local radome patch with a sweep-frequency band of microwaves having a frequency band of at least two-thirds octave surrounding the design frequency of the radome. Alternatively, a harmonic band of three times the design frequency band may be utilized in the method when compact equipment is important. A sweep-frequency generator is coupled to a reflectometer for response to the band of illuminated and reflected microwaves from a local radome patch to provide an X-Y plot of reflectivity as a function of the sweep-frequency. The sweep-frequency is related to scan angle using known radome equations.
Inventors
- 👤 Clarence D. Lunden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:38
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01R27/04
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
A method for determining at a localized area radio-frequency performance including delamination and/or water entrapment or other material or thickness changes to a radome designed to pass electomagnetic waves at a prescribed frequency, said method including the steps of: illuminating by normal incidence a local radome patch with a sweep-frequency band of microwaves covering at least one-half octave centered, substantially, on said prescribed frequency, coupling a reflectometer for response to the band of illuminating and reflected microwaves directed onto and from said local radome patch, respectively, producing an X-Y plot corresponding to microwave reflectivity as a function of said microwave sweep-frequency, and calibrating said X-Y plot with a signal coresponding to the reflectivity of a dielectric slab, block or a radome patch with known radio-frequency performance.
Claim 2
Independent Claim
126 words
A method for determining at a localized area radio-frequency performance including delamination and/or water entrapment or other material or thickness changes to a radome designed to pass electomagnetic waves at a prescribed frequency, said method including the steps of: illuminating by normal incidence a local radome patch with a sweep-frequency band of microwaves covering at least one-half octave centered, substantially, on said prescribed frequency, coupling a reflectometer for response to the band of illuminating and reflected microwaves directed onto and from said local radome patch, respectively, producing an X-Y plot corresponding to microwave reflectivity as a function of said microwave sweep-frequency, and calibrating said X-Y plot with a signal coresponding to the reflectivity of a dielectric slab, block or a radome patch with known radio-frequency performance.
Claim 3
Dependent Claim
28 words
The method according to claim 1 including the further step for transforming said plot by transposing said sweep-frequency band into a corresponding scan angle band using radome equations.
Claim 4
Dependent Claim
70 words
The method according to claim 2 wherein the wavelength of a microwave frequency within said sweep-frequency band is related to a corresponding scan angle, for A-sandwich radomes, by the expression: S = η λ.sub.o /4 SEC i.sub.o where: S = the thickness of the radome patch, λ o = the wavelength of said microwave frequency within said sweep-frequency band, i o = said scan angle, and η = a constant.
Claim 5
Dependent Claim
38 words
The method according to claim 3 where λ o 1 is the wavelength of a microwave frequency within said sweep-frequency band and λ o 1 is given by the expression λ.sub.o.sup.1 = λ.sub.o /3 where: η = 3.
Claim 6
Dependent Claim
34 words
The method according to claim 1 wherein, for an A-sandwich radome, said sweep-frequency band of microwaves is selected to cover at least one-half octave centered substantially on the third harmonic of said prescribed frequency.
Claim 7
Dependent Claim
28 words
The method according to claim 1 wherein said illuminating a local radome patch includes directing said sweep-frequency band of microwaves from a sweep-frequency generator along a rectangular waveguide.
Claim 8
Dependent Claim
32 words
The method according to claim 6 wherein said illuminating a local radome patch further includes using an E-plane sectoral horn to radiate said sweep-frequency band of microwaves onto said local radome patch.
Claim 9
Dependent Claim
31 words
The method according to claim 7 wherein said E-plane sectoral horn is arranged in a juxtaposed relation with said local radome patch for normal incidence of the sweep-frequency band of microwaves.
Claim 10
Dependent Claim
57 words
The method according to claim 8 including the further step of calibrating said reflectometer by arranging a block of wood having one end larger than the aperture in said E-plane sectoral horn in a juxtaposed relation therewith while a tapered end projects outwardly from said horn to eliminate microwave second-surface reflections preparatory to said step of illuminating.
Claim 11
Dependent Claim
30 words
The method according to claim 1 wherein said step of comparing includes developing envelope patterns of known plot signals each corresponding to a radome patch with a known radio-frequency performance.
Claim 12
Dependent Claim
30 words
The method according to claim 1 including the further step of calibrating said reflectometer to develop a flat, two-way applicator response by the reflectometer preparatory to said step of illuminating.
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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |