US3697993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Airborne pulse doppler radar system
Assignee: Westinghouse Electric Corp
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Filing: 1969-09-15
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Granted: 1972-10-10
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Expires: 1989-09-15
Abstract
Abstract An airborne pulse doppler radar system whose sidelobe clutter amplitude is minimized by providing an antenna whose main beam subtends a small angle and whose radiated energy is concentrated in the main beam and the first few sidelobes and by providing a main beam band rejection filter whose rejection band is closely matched to the antenna main beam clutter frequency band.
Inventors
- 👤 William S Jones
- 👤 Philip S Hacker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:07
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/60; G01S13/52; G01S13/522; G01S13/524; G01S13/53; H; H01; H01Q; H01Q21/00; H01Q21/0006; H01Q21/0037; H01Q21/0043; H01Q21/005
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
170 words
In an airborne pulse doppler radar system for detecting moving targets in the presence of ground clutter and arranged to produce a pulse signal formed of a carrier wave having a given frequency and having a noise content such that the given frequency varies within predetermined limits, the improvement comprising: an antenna having a plurality of parallel, rectangular waveguides having a series of radiating slots cut into one narrow sidewall, an input manifold connecting one end of each of said waveguides in parallel for delivering electromagnetic wave energy thereto, said antenna having a radiation lobe pattern which exhibits a narrow main beam and a concentration of radiated energy in the main beam and in the first few near sidelobes; and a main beam clutter rejection filter connected to filter the return signals received by said antenna and having a rejection frequency band substantially equal to the actual bandwidth of the main beam clutter frequency component of such return signals for a radiated signal whose frequency varies within such predetermined limits.
Claim 2
Dependent Claim
170 words
In an airborne pulse doppler radar system for detecting moving targets in the presence of ground clutter and arranged to produce a pulse signal formed of a carrier wave having a given frequency and having a noise content such that the given frequency varies within predetermined limits, the improvement comprising: an antenna having a plurality of parallel, rectangular waveguides having a series of radiating slots cut into one narrow sidewall, an input manifold connecting one end of each of said waveguides in parallel for delivering electromagnetic wave energy thereto, said antenna having a radiation lobe pattern which exhibits a narrow main beam and a concentration of radiated energy in the main beam and in the first few near sidelobes; and a main beam clutter rejection filter connected to filter the return signals received by said antenna and having a rejection frequency band substantially equal to the actual bandwidth of the main beam clutter frequency component of such return signals for a radiated signal whose frequency varies within such predetermined limits.
Claim 3
Dependent Claim
106 words
For use in an airborne doppler radar system for detecting moving targets in the presence of ground clutter, an antenna having a radiation lobe pattern which exhibits a narrow main beam and a concentration of radiated energy in the main beam and in the first few near sidelobes, said antenna being composed of: a plurality of parallel, rectangular, radiating waveguides each having a plurality of radiating slots formed in one narrow side wall; an input manifold connected to one end of each of said waveguides for delivering electromagnetic wave energy thereto; and wave launching means connected to said manifold for delivering pulse modulated radar signals thereto.
Claim 4
Dependent Claim
106 words
For use in an airborne doppler radar system for detecting moving targets in the presence of ground clutter, an antenna having a radiation lobe pattern which exhibits a narrow main beam and a concentration of radiated energy in the main beam and in the first few near sidelobes, said antenna being composed of: a plurality of parallel, rectangular, radiating waveguides each having a plurality of radiating slots formed in one narrow side wall; an input manifold connected to one end of each of said waveguides for delivering electromagnetic wave energy thereto; and wave launching means connected to said manifold for delivering pulse modulated radar signals thereto.
Claim 5
Dependent Claim
27 words
An arrangement as defined in claim 2 wherein said slots in each of said radiating waveguides are inclined in alternately opposite directions with respect to one another.
Claim 6
Dependent Claim
30 words
An arrangement as defined in claim 3 wherein, for each said radiating waveguide, the inclination of said slots varies progressively from the middle of said guide to the ends thereof.
Claim 7
Dependent Claim
38 words
An arrangement as defined in claim 4 wherein the inclination of said slots decreases progressively from the middle of said waveguide to the ends thereof with respect to the direction between the wide lateral walls of said waveguide.
Claim 8
Dependent Claim
62 words
An arrangement as defined in claim 5 wherein, for each said radiating waveguide, said slots are spaced from one another by a distance equal to one-half the wavelength, in said waveguide, of the wave being propagated, and said waveguide is provided with a short-circUit termination at its other end spaced one-quarter of the guide wavelength from the last one of said slots.
Claim 9
Dependent Claim
46 words
An arrangement as defined in claim 2 wherein said input manifold is constituted by a rectangular waveguide having the same transverse dimensions as each of said radiating waveguides and provided with a plurality of coupling slots each communicating with a respective one of said radiating waveguides.
Claim 10
Dependent Claim
22 words
An arrangement as defined in claim 7 wherein said coupling slots are inclined in alternately opposite directions with respect to one another.
Claim 11
Dependent Claim
50 words
An arrangement as defined in claim 8 wherein said coupling slots are spaced from one another by a distance equal to one-half the wavelength, in said input manifold waveguide, of the wave being propagated, and each said coupling slot is centered on the longitudinal axis of its associated radiating guide.
Claim 12
Dependent Claim
28 words
An arrangement as defined in claim 2 wherein each of said radiating slots is cut to a predetermined depth into the wide lateral walls of its associated waveguide.
Claim 13
Dependent Claim
60 words
An arrangement as defined in claim 2 further comprising plate means disposed between each adjacent pair of said radiating waveguides and extending substantially along the length of the radiating portion of said guides, said plate means being set in from said narrow waveguide side walls in which said slots are formed to define choke grooves having an accurately determined depth.
References Cited (Backward Citations)
US3508275A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |