US4117485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar target cross section control method and means
Assignee: United States Department of the Air Force
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Filing: 1971-01-05
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Granted: 1978-09-26
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Expires: 1991-01-05
Abstract
Abstract Radar target back scattering is controlled by an impedance loading technique. The target is loaded with a variable impedance that is adjusted in response to the frequency of any incident radar signal to achieve optimum reflectivity for that particular frequency. Either radar target cross section reduction or enhancement is achieved over a broad band of frequencies by appropriate control of a voltage variable capacitance diode.
Inventors
- 👤 Benjamin B. Gorr
- 👤 Richard B. Mack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:37
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/38; H; H01; H01Q; H01Q3/00; H01Q3/44
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
79 words
A radar target having cross section control means, said cross section control means comprising means for detecting incident electromagnetic wave energy, means for generating therefrom a control signal responsive to the frequency thereof, and means for loading said radar target with a variable impedance load, said variable impedance load having electrical characteristics that effect non-increasing capacitive reactance values in response to increasing incident electromagnetic wave frequency, said variable impedance load being responsive to and controlled by said control signal.
Claim 2
Dependent Claim
79 words
A radar target having cross section control means, said cross section control means comprising means for detecting incident electromagnetic wave energy, means for generating therefrom a control signal responsive to the frequency thereof, and means for loading said radar target with a variable impedance load, said variable impedance load having electrical characteristics that effect non-increasing capacitive reactance values in response to increasing incident electromagnetic wave frequency, said variable impedance load being responsive to and controlled by said control signal.
Claim 3
Dependent Claim
35 words
A radar target having cross section control means as defined in claim 1 wherein said variable impedance load has electrical characteristics that effect decreasing capacitive reactance values in response to increasing incident electromagnetic wave frequency.
Claim 4
Dependent Claim
46 words
A radar target having cross section control means as defined in claim 1 wherein said variable impedance load comprises a coaxial microwave cavity and a voltage variable capacitor diode, said voltage variable capacitor diode being in series relationship with the center conductor of said coaxial cavity.
Claim 5
Dependent Claim
77 words
A radar target having cross section control means as defined in claim 1 wherein said means for detecting incident electromagnetic wave energy comprises a microwave antenna and said means for generating a control signal comprises an RF amplifier adapted to amplifying the output of said microwave antenna, a limiter connected to the output of said amplifier, discriminator means connected to the output of said limiter and a DC amplifier connected to the output of said discriminator means.
Claim 6
Independent Claim
50 words
The method of controlling backscatter from a radar target comprising the steps of `loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves optimum selected backscatter at the existing incident radar signal frequency.
Claim 7
Independent Claim
50 words
The method of controlling backscatter from a radar target comprising the steps of `loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves optimum selected backscatter at the existing incident radar signal frequency.
Claim 8
Independent Claim
49 words
The method of enhancing backscatter from a radar target comprising the steps of loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves maximum backscatter at the existing incident radar signal frequency.
Claim 9
Independent Claim
49 words
The method of enhancing backscatter from a radar target comprising the steps of loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves maximum backscatter at the existing incident radar signal frequency.
Claim 10
Independent Claim
49 words
The method of reducing backscatter from a radar target comprising the steps of loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves minimum backscatter at the existing incident radar signal frequency.
Claim 11
Independent Claim
49 words
The method of reducing backscatter from a radar target comprising the steps of loading said target with a variable impedance having a voltage variable capacitance diode, and adjusting the capacitance diode control voltage to establish an impedance value that achieves minimum backscatter at the existing incident radar signal frequency.
Claim 12
Independent Claim
80 words
The method of providing radar target cross section reduction comprising the steps of loading a radar target with a variable capacitance impedance, determining the values of said impedance that effect maximum cross section reduction for a range of incident radar signal frequencies, detecting incident radar signals, generating a control signal representative of the detected radar signal frequency, and varying said variable impedance therewith to provide the optimum cross section reduction impedance value for the incident radar signal frequency represented thereby.
Claim 13
Independent Claim
80 words
The method of providing radar target cross section reduction comprising the steps of loading a radar target with a variable capacitance impedance, determining the values of said impedance that effect maximum cross section reduction for a range of incident radar signal frequencies, detecting incident radar signals, generating a control signal representative of the detected radar signal frequency, and varying said variable impedance therewith to provide the optimum cross section reduction impedance value for the incident radar signal frequency represented thereby.
Claim 14
Dependent Claim
23 words
The method of providing radar target cross section reduction defined in claim 8 wherein said variable impedance includes a voltage variable capacitance diode.
Claim 15
Independent Claim
80 words
The method of providing radar target cross section enhancement comprising the steps of loading a radar target with a variable capacitance impedance, determining the values of said impedance that effect maximum cross section enhancement for a range of incident radar signal frequencies, detecting incident radar signals, generating a control signal representative of the detected radar signal frequency, and varying said variable impedance therewith to provide the optimum cross section enhancement impedance value for the incident radar signal frequency represented thereby.
Claim 16
Independent Claim
80 words
The method of providing radar target cross section enhancement comprising the steps of loading a radar target with a variable capacitance impedance, determining the values of said impedance that effect maximum cross section enhancement for a range of incident radar signal frequencies, detecting incident radar signals, generating a control signal representative of the detected radar signal frequency, and varying said variable impedance therewith to provide the optimum cross section enhancement impedance value for the incident radar signal frequency represented thereby.
Claim 17
Dependent Claim
21 words
The method of providing radar target enhancement defined in claim 10 wherein said variable impedance includes a voltage variable capacitance diode.
References Cited (Backward Citations)
US2931031A
Cited
US3098973A
Cited
US3096494A
Cited
US3277476A
Cited
US3309704A
Cited
US3325808A
Cited
US3305863A
Cited
US3568194A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-25 | 1982-03-27 | 1982-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-25 | 1986-03-27 | 1986-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-25 | 1990-03-27 | 1990-09-26 | $7700.00 | Window Closed / Lapsed |