US3877032A
Expired / Lapsed
US
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Reflector antenna with improved scanning
Assignee: Harris Corp
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Filing: 1973-07-16
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Granted: 1975-04-08
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Expires: 1993-07-16
Abstract
Abstract A Cassegrainian antenna system has a planar array as the feed. An intermediate reflector is positioned in the near field of the array for substantially collimated illumination with all array elements operating in phase. Accordingly, an on-axis main beam is radiated from the main reflector upon illumination by energy from the intermediate reflector. By impressing a linear phase gradient across the array, the main beam is controllably tilted off-axis.
Inventors
- 👤 Jack Rosa
- 👤 Harry R Phelan
- 👤 Jr Attilio F Sciambi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:34
CPC Classifications
H; H01; H01Q; H01Q19/00; H01Q19/10; H01Q19/18; H01Q19/19; H01Q3/00; H01Q3/26; H01Q3/2658
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
170 words
A reflector-type antenna system, comprising a feed including a planar array of antenna elements, said array having an aperture area A, a main reflector having a boresight axis, an intermediate reflector to couple energy from said feed to said main reflector, and means for exciting said feed so as to radiate energy having wavelength .lambda. toward said intermediate reflector such that the radiated energy, when the array elements are all excited in phase is substantially a collimated energy beam extending along said axis, said intermediate reflector being spaced along said axis a distance D from said array to receive a substantially collimated feed beam of energy from said array when all of the array elements are excited in phase, whereby to effect the radiation of an on-axis main beam from said main reflector, said distance D being less than about A divided by 5 .lambda., said exciting means including means for exciting said array elements with a linear phase gradient across said array to selectively tilt said main beam off-axis.
Claim 2
Dependent Claim
170 words
A reflector-type antenna system, comprising a feed including a planar array of antenna elements, said array having an aperture area A, a main reflector having a boresight axis, an intermediate reflector to couple energy from said feed to said main reflector, and means for exciting said feed so as to radiate energy having wavelength .lambda. toward said intermediate reflector such that the radiated energy, when the array elements are all excited in phase is substantially a collimated energy beam extending along said axis, said intermediate reflector being spaced along said axis a distance D from said array to receive a substantially collimated feed beam of energy from said array when all of the array elements are excited in phase, whereby to effect the radiation of an on-axis main beam from said main reflector, said distance D being less than about A divided by 5 .lambda., said exciting means including means for exciting said array elements with a linear phase gradient across said array to selectively tilt said main beam off-axis.
Claim 3
Dependent Claim
171 words
An antenna system, comprising a planar array of feed elements, said array having an aperture area A, means for exciting said array to radiate energy of wavelength .lambda. such that when said elements are all excited in phase the radiated energy is a first beam that is essentially collimated for a near field distance along an axis of said array, an intermediate reflector spaced along said array axis from said array a distance D and positioned relative to said array for illumination by energy radiated from said array in said first beam, where D < A/(5 .lambda. ), and a main reflector having a main axis coincident with the array axis and responsive to energy coupled thereto by said intermediate reflector upon illumination of said intermediate reflector by said array to form a highly directional main beam of said energy, said exciting means including means for exciting all of said feed elements to produce a phase gradient across said array for selectively tilting said main beam relative to said main axis.
Claim 4
Dependent Claim
171 words
An antenna system, comprising a planar array of feed elements, said array having an aperture area A, means for exciting said array to radiate energy of wavelength .lambda. such that when said elements are all excited in phase the radiated energy is a first beam that is essentially collimated for a near field distance along an axis of said array, an intermediate reflector spaced along said array axis from said array a distance D and positioned relative to said array for illumination by energy radiated from said array in said first beam, where D < A/(5 .lambda. ), and a main reflector having a main axis coincident with the array axis and responsive to energy coupled thereto by said intermediate reflector upon illumination of said intermediate reflector by said array to form a highly directional main beam of said energy, said exciting means including means for exciting all of said feed elements to produce a phase gradient across said array for selectively tilting said main beam relative to said main axis.
Claim 5
Dependent Claim
156 words
An antenna system comprising a planar array of antenna elements, said array having an aperture area A and an array axis; a main reflector; an intermediate reflector for receiving energy from said feed array and reflecting said energy to said main reflector; and means for exciting said feed array so as to radiate energy having wavelength .lambda. such that said radiated energy, when the feed array elements are substantially all excited in phase, is a substantially collimated energy beam extending along said array axis to said intermediate reflector, said intermediate reflector being spaced a distance D from said feed array, said distance D being less than about A divided by 5 .lambda., thereby to effect the radiation of a main beam in a first direction from said main reflector; said exciting means including means for exciting said array elements with a phase gradient across said array to selectively direct said main beam to a different direction.
Claim 6
Dependent Claim
156 words
An antenna system comprising a planar array of antenna elements, said array having an aperture area A and an array axis; a main reflector; an intermediate reflector for receiving energy from said feed array and reflecting said energy to said main reflector; and means for exciting said feed array so as to radiate energy having wavelength .lambda. such that said radiated energy, when the feed array elements are substantially all excited in phase, is a substantially collimated energy beam extending along said array axis to said intermediate reflector, said intermediate reflector being spaced a distance D from said feed array, said distance D being less than about A divided by 5 .lambda., thereby to effect the radiation of a main beam in a first direction from said main reflector; said exciting means including means for exciting said array elements with a phase gradient across said array to selectively direct said main beam to a different direction.
Claim 7
Dependent Claim
36 words
An antenna system as defined in claim 3 and wherein said main reflector has a main axis of geometric symmetry coinciding with said array axis, and said intermediate reflector is located on both of said axes.
Claim 8
Dependent Claim
13 words
The system of claim 1, wherein said reflector-type antenna is a Cassegrainian antenna.
Claim 9
Dependent Claim
35 words
The reflector-type antenna system of claim 1, wherein said exciting means includes means for producing rotation of the tilted beam about the axis of the main reflector by varying the phasing of the array elements.
Claim 10
Dependent Claim
21 words
The antenna system of claim 2, wherein said array, said intermediate reflector, and said main reflector are in a Cassegrainian configuration.
Claim 11
Dependent Claim
12 words
The antenna system of claim 2, wherein said phase gradient is linear.
Claim 12
Dependent Claim
28 words
The antenna system of claim 2, wherein said exciting means includes means for varying said phase gradient across the array to rotate the tilted beam about said axis.
References Cited (Backward Citations)
US3569976A
Cited
US3534365A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |