EP0139482A2 - Antenne double réflecteur à balayage - Google Patents

Antenne double réflecteur à balayage Download PDF

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Publication number
EP0139482A2
EP0139482A2 EP84306454A EP84306454A EP0139482A2 EP 0139482 A2 EP0139482 A2 EP 0139482A2 EP 84306454 A EP84306454 A EP 84306454A EP 84306454 A EP84306454 A EP 84306454A EP 0139482 A2 EP0139482 A2 EP 0139482A2
Authority
EP
European Patent Office
Prior art keywords
reflector
dish
antenna
main
dishes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP84306454A
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German (de)
English (en)
Other versions
EP0139482A3 (fr
Inventor
William John British Aerospace P.L.C. Hall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems PLC
Original Assignee
British Aerospace PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Aerospace PLC filed Critical British Aerospace PLC
Publication of EP0139482A2 publication Critical patent/EP0139482A2/fr
Publication of EP0139482A3 publication Critical patent/EP0139482A3/fr
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/12—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems
    • H01Q3/16—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device
    • H01Q3/20—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device wherein the primary active element is fixed and the reflecting device is movable

Definitions

  • inis invention relates to antenna systems, more particularly but not exclusively, antenna systems for use on board spacecraft such as communications satellites.
  • a known, advantageous way of doing this is to use an antenna system comprising a movable reflector dish but a fixed antenna feed (the feed being the horn, waveguide aperture or the like from which the communications signal is emitted to the dish or which receives the signal from the dish).
  • the antenna feed should be positioned at the focus of the reflector dish.
  • the movement of the dish to scan the antenna pointing direction will not be about this focal point.
  • the fixed position of the feed will not remain at the focal point and there will be a loss of gain and performance.
  • An object of this invention is to substantially reduce or even eliminate the separation of the focus from the feed during movement of the reflector.
  • an antenna system comprising support means, a main radio-frequency reflector dish of which the reflector surface is its concave surface, an auxiliary radio-frequency reflector dish of which the reflector surface is its convex surface, the two dishes being fixed with respect to one another with the reflector surfaces thereof facing one another, the two dishes being supported by said support means for together turning with respect to the support means about a point lying between the reflector surfaces, antenna pointing means connected to the reflector dishes and operable for controlling said turning of the reflector dishes to point the main reflector dish in a desired direction, and antenna feed means which is fixed with respect to the support means and which has a portion at least near to said point for emitting radio-frequency energy to or receiving such energy from said main reflector dish by way of said auxiliary reflector dish.
  • the antenna system is particularly suitable for use in space but may be useful for other applications.
  • Cassegrain, Gregorian and Newtonian reflector dishes may be used as well as other forms shaped for a particular application.
  • FIG. 1 shows part of a spacecraft 1 to which there is mounted a Cassegrain antenna system comprising a main parabolic reflector dish 2 and an auxiliary reflector dish 3 which is fixed, for example by way of support arms (not shown), to the main dish 2 such that the convex reflector surface of the dish 3 faces the concave reflector surface of dish 2.
  • the dish 2 is fixed to the movable part 4 of a swash-plate antenna pointing mechanism of which a fixed part 5 is supported via a hollow cone-shaped support pillar 6 on the surface of the spacecraft.
  • the antenna pointing mechanism is shown only diagrammatically but its construction which includes a suitable drive motor (not shown) and its operation are well known to those skilled in the art.
  • the effect of dish 3 is to produce a virtual image of the horn aperture at point 9, which point is at least near the focal point of the dish 2.
  • the horn aperture is in fact positioned at least near the point about which the antenna dish 3 is turned by the antenna pointing mechanism.
  • the main and auxiliary reflector dishes move together and rotate as a unit there are no distortions introduced when the beam scans.
  • Some loss of gain occurs through spillover at the edges of the auxiliary reflector as illustrated at 10 in Figure 2 but these losses may be controlled by increasing the subtended angle of the auxiliary reflector from the focus.
  • the illustrated system may be able to achieve comparatively large scans with low loss (eg 35 beamwidths with an approximate 1 dB loss).
  • the centre of rotation of the reflector dish assembly may be displaced somewhat from the feed horn aperture, say to accommodate other system design features, but increased distortion will occur.
  • r.f. sensing components may be attached to the feed horn.
  • the scanning process introduces asymmetry into the main reflector aperture illumination which has more serious effects upon the shape of a difference pattern (see Figure 3) than a sum pattern.
  • a combination of sum and difference patterns may be used to squint the reception beam pattern of the beacon signal receiving components so as to follow the rotation of the antenna system and hence correct the asymmetry.
  • the sum and difference patterns may be generated by either multiple horn systems or mode extraction systems in which the signals are obtained from the various modes of waveguide.
  • the modes TEll or HEll are normally used for sum signal and the combinations TM01/TE21, dual TE21 and TM01"TE01 as the difference signal.
  • the antenna sum and difference modes are added which squint the feed illumination to follow the auxiliary reflector. This is also possible with the communications signal but it is not usually necessary.
  • the addition of sum and difference modes may be made in several ways.
  • the modes can be added in an r.f. comparator, in a multiplexer modulator or at low frequency or baseband within the tracking receiver.
  • the sum pattern is usually added at a low level (eg 20dB) relative to the difference pattern.

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Aerials With Secondary Devices (AREA)
EP84306454A 1983-09-22 1984-09-21 Antenne double réflecteur à balayage Withdrawn EP0139482A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8325386 1983-09-22
GB8325386 1983-09-22

Publications (2)

Publication Number Publication Date
EP0139482A2 true EP0139482A2 (fr) 1985-05-02
EP0139482A3 EP0139482A3 (fr) 1986-07-16

Family

ID=10549149

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84306454A Withdrawn EP0139482A3 (fr) 1983-09-22 1984-09-21 Antenne double réflecteur à balayage

Country Status (2)

Country Link
EP (1) EP0139482A3 (fr)
JP (1) JPS6089104A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656671A1 (fr) * 1993-12-02 1995-06-07 Alcatel Espace Antenne orientable avec conservation des axes de polarisation
US7911403B2 (en) 2007-03-16 2011-03-22 Mobile Sat Ltd. Vehicle mounted antenna and methods for transmitting and/or receiving signals
FR2952238A1 (fr) * 2009-11-03 2011-05-06 Thales Sa Montage d'antenne a faisceau mobile
RU2574351C2 (ru) * 2009-11-03 2016-02-10 Таль Антенная конструкция с подвижным пучком
CN109301452A (zh) * 2018-09-19 2019-02-01 中国科学院遥感与数字地球研究所 S/X/Ka三轴天线
US10230164B2 (en) 2016-09-14 2019-03-12 Raytheon Company Antenna positioning mechanism

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2074724A1 (fr) * 1970-01-21 1971-10-08 Comp Generale Electricite
US3708795A (en) * 1970-02-10 1973-01-02 Hawker Siddeley Aviation Ltd Cassegrain antenna mounted in aircraft nose cone
US3845483A (en) * 1972-03-08 1974-10-29 Nippon Electric Co Antenna system
GB2031655A (en) * 1978-09-08 1980-04-23 Marconi Co Ltd Dual beam antenna system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2074724A1 (fr) * 1970-01-21 1971-10-08 Comp Generale Electricite
US3708795A (en) * 1970-02-10 1973-01-02 Hawker Siddeley Aviation Ltd Cassegrain antenna mounted in aircraft nose cone
US3845483A (en) * 1972-03-08 1974-10-29 Nippon Electric Co Antenna system
GB2031655A (en) * 1978-09-08 1980-04-23 Marconi Co Ltd Dual beam antenna system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
AP-S INTERNATIONAL SYMPOSIUM, 11th-15th October 1976, Amherst, US, pages 20-23, IEEE, New York, US; L.J. COOPER et al.: "Off-axis patterns of high-efficiency and conventional cassegrain antennas with multimode feed horns" *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656671A1 (fr) * 1993-12-02 1995-06-07 Alcatel Espace Antenne orientable avec conservation des axes de polarisation
FR2713404A1 (fr) * 1993-12-02 1995-06-09 Alcatel Espace Antenne orientale avec conservation des axes de polarisation.
US5796370A (en) * 1993-12-02 1998-08-18 Alcatel Espace Orientable antenna with conservation of polarization axes
US8228253B2 (en) 2007-03-16 2012-07-24 Mobile Sat Ltd. Vehicle mounted antenna and methods for transmitting and/or receiving signals
US7911403B2 (en) 2007-03-16 2011-03-22 Mobile Sat Ltd. Vehicle mounted antenna and methods for transmitting and/or receiving signals
FR2952238A1 (fr) * 2009-11-03 2011-05-06 Thales Sa Montage d'antenne a faisceau mobile
WO2011054669A1 (fr) 2009-11-03 2011-05-12 Thales Montage d'antenne a faisceau mobile
CN102656746A (zh) * 2009-11-03 2012-09-05 塔莱斯公司 移动波束天线装置
US8878745B2 (en) 2009-11-03 2014-11-04 Thales Mobile-beam antenna mounting
CN102656746B (zh) * 2009-11-03 2015-08-19 塔莱斯公司 移动波束天线装置
RU2574351C2 (ru) * 2009-11-03 2016-02-10 Таль Антенная конструкция с подвижным пучком
US10230164B2 (en) 2016-09-14 2019-03-12 Raytheon Company Antenna positioning mechanism
CN109301452A (zh) * 2018-09-19 2019-02-01 中国科学院遥感与数字地球研究所 S/X/Ka三轴天线
CN109301452B (zh) * 2018-09-19 2024-02-02 中国科学院遥感与数字地球研究所 S/X/Ka三轴天线

Also Published As

Publication number Publication date
JPS6089104A (ja) 1985-05-20
EP0139482A3 (fr) 1986-07-16

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Inventor name: HALL, WILLIAM JOHNBRITISH AEROSPACE P.L.C.