EP0086399B1 - Antenne à plusieurs réflecteurs - Google Patents

Antenne à plusieurs réflecteurs Download PDF

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Publication number
EP0086399B1
EP0086399B1 EP83100957A EP83100957A EP0086399B1 EP 0086399 B1 EP0086399 B1 EP 0086399B1 EP 83100957 A EP83100957 A EP 83100957A EP 83100957 A EP83100957 A EP 83100957A EP 0086399 B1 EP0086399 B1 EP 0086399B1
Authority
EP
European Patent Office
Prior art keywords
radiators
reflector
individual
group
auxiliary
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.)
Expired
Application number
EP83100957A
Other languages
German (de)
English (en)
Other versions
EP0086399A1 (fr
Inventor
Eberhard Dipl.-Phys. Dr. Frisch
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.)
Airbus Defence and Space GmbH
Original Assignee
Messerschmitt Bolkow Blohm AG
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 Messerschmitt Bolkow Blohm AG filed Critical Messerschmitt Bolkow Blohm AG
Publication of EP0086399A1 publication Critical patent/EP0086399A1/fr
Application granted granted Critical
Publication of EP0086399B1 publication Critical patent/EP0086399B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/18—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces
    • H01Q19/19—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface

Definitions

  • the invention relates to a multi-reflector antenna for a geostationary satellite, with a parabolic main reflector, at least one auxiliary reflector and a number of individual emitters which emit on the main reflector in the direction of different target areas on earth, the entirety of the individual emitters being formed into a plurality of adjacent individual emitters Spotlight groups is divided.
  • Multi-reflector antennas which are carried by geostationary communication satellites, are intended to illuminate a coverage area below them on the earth's surface, subject to certain conditions. This is done by a number of radiation lobes. the neighboring target areas are assigned. Each lobe is generated by a single radiator, the radiation of which is directed from the main reflector to the corresponding target area. Each lobe illuminates the generally circular target area assigned to it on the surface of the earth in such a way that the incident radiation intensity falls radially outwards from the center of this target area. Adjacent radiation lobes overlap in their outer areas and are closer to each other the less the drop in intensity at the edges of a target area should be.
  • a multi-reflector antenna in which an intermediate reflector is switched between the individual radiators and the parabolic main reflector, which deflects the radiation of the individual radiators towards the main reflector. Both the main and the intermediate reflector are offset with respect to the parabolic axis, so that shadowing of the radiation emanating from the main reflector is avoided by the intermediate reflector.
  • a central single radiator is directed so that its radiation is centered on the centers of the intermediate and the main reflector and leaves the latter parallel to the parabolic axis assigned to the main reflector.
  • the individual emitters adjacent to this central single emitter are directed such that their radiation after reflection by the intermediate reflector is also centered on the center of the main reflector, but is reflected by the latter in different spatial directions that are not parallel to the parabolic axis.
  • a single antenna for such two-reflector antennas which are assigned to the Cassegrain or Gregory type, are usually used horn antenna.
  • the dimensions of these, in particular with regard to their aperture, depend on the frequency and the reflector diameters. For this reason, the individual radiators cannot be moved as close together as desired. However, this proves to be very cumbersome if the requirement is to be met that the radiation drop at the edges of the adjacent target areas on the earth's surface should not exceed a certain predetermined value.
  • the stricter the requirements in this regard the closer the lobes, the width of which is approximately fixed at a given frequency and diameter of the main reflector, must be close together.
  • the radiation intensity in the target area should not drop by more than 3 dB, for example, this is the case with the arrangement described above far no longer realizable.
  • a multi-reflector antenna of the type mentioned is known.
  • This is also a two-reflector antenna, in which the entirety of the individual radiators directed at the auxiliary reflector is, however, broken down into radiator groups of adjacent individual radiators.
  • the individual emitters of a radiation group are also assigned adjacent radiation lobes or target areas. Since the individual emitters have certain minimum dimensions purely geometrically, the radiation lobes cannot move as close together as desired and thus only overlap to a limited extent. It follows from this that in the target area, with increasing distance from the center of the radiation lobe, the intensity of the received radiation power decreases more and more until the intensity in the area of the neighboring radiation lobe rises again. On the other hand, there is a requirement that the intensity drops in the area of a radiation lobe should be as small as possible.
  • the invention has for its object to provide a multi-reflector antenna of the type mentioned, with which it is possible to illuminate a larger target area on the earth with the help of overlapping radiation lobes so that the occurring drops in intensity can be kept as low as possible.
  • each radiator group is assigned its own auxiliary reflector, which is irradiated by the individual radiators of the group and reflects the radiation towards the main reflector, and the individual radiators are directed to each radiator group in such a way that neighboring target areas are supplied by individual radiators from different radiator groups .
  • auxiliary reflectors are now used, each of which is assigned a radiator group consisting of individual radiators that are adjacent to one another.
  • the individual emitters in a group of emitters no longer need to be aimed at directly adjacent, for example circular, target areas on the earth's surface.
  • the gaps between the radiation lobes of one radiator group that arise with regard to the permissible intensity fluctuations can be supplied by appropriately aligned radiation lobes of other radiator groups. Immediately adjacent circular target areas are therefore served by individual emitters from different emitter groups.
  • auxiliary reflectors When using three auxiliary reflectors, for example, there is a grid of circular, overlapping target areas on the surface of the earth, of which any one is supplied by a single radiator of the first radiator group and is surrounded in a symmetrical manner by six target areas, which alternate between the two other radiator groups are operated, with a total of three individual radiators from the second and the third radiator group being involved.
  • This grid can also be traced back to a regular basic structure, which consists of three mutually displaced networks based on equilateral triangles, the centers of the radiation lobes assigned to the individual emitters each lying in the corner points.
  • the grid from the target areas assigned to the individual radiators can be designed to be as complicated as desired.
  • the spatial directions assigned to the individual radiators of a radiator group can be further apart in terms of angle, the more individual radiators are distributed over the more radiator groups or auxiliary reflectors.
  • the auxiliary reflectors In the further configuration of the multi-reflector antenna according to the invention, it proves to be expedient to equip the auxiliary reflectors with curved reflector surfaces each having two focal points. It is important to ensure that one focal point coincides with the focal point of the parabolic main reflector and that the radiator group assigned to the auxiliary reflector is arranged at its other focal point.
  • the radiator groups are all mapped onto the focal area of the parabolic main reflector.
  • the reflector surfaces of the auxiliary reflectors can, according to the Cassegrain type, be excerpts from rotational hyperboloids or, according to the Gregory type, excerpts from rotational ellipsoids.
  • optical multi-mirror systems instead of auxiliary reflectors, each of which must have two focal points.
  • the invention is preferably applicable to multi-reflector antennas in an offset arrangement.
  • the use of axisymmetric arrangements is also within the scope of the invention, although shadowing by the auxiliary reflectors must be accepted.
  • the focal point axes given by the focal points of the auxiliary reflectors are inclined relative to the axis of the parabolic main reflector.
  • a simple way of orienting several auxiliary reflectors is to arrange their other focal points on a tiny circular line of this type.
  • completely identical reflector surfaces are used, which are only pivoted around different angles of rotation with respect to the axis of the parabolic main reflector.
  • the inclination of the assigned focal axis with respect to the named axis is the same for all auxiliary reflectors.
  • the focal point distances on the focal point axes assigned to the individual auxiliary reflectors can be at least partially different.
  • the reflector surfaces of the individual auxiliary reflectors can therefore be based on differently curved rotational hyperboloids, the auxiliary reflectors can thus be arranged at different distances from the focal point of the parabolic main reflector.
  • the inclinations of the focal axes can be different from the axis of the main reflector.
  • auxiliary reflectors partially overlap each other. Then only care must be taken to ensure that these neighboring auxiliary reflectors are selective for orthogonal polarization directions or different frequency ranges.
  • grid-like structures consisting of rigid or tensioned parallel metal strips can be used. If about three auxiliary reflectors are provided, of which the middle one at its two opposite edges is overlapped by one of the two outer edges, the latter can be designed, for example, for horizontal, the former for vertical polarization.
  • auxiliary reflectors In a similar manner, frequency-selective reflectors known per se can be used as auxiliary reflectors which partially overlap one another.
  • the invention also includes the case that one of the radiator groups resulting from the subdivision of the totality of the individual radiators is not assigned an auxiliary reflector, rather this radiator group is arranged at the focal point of the parabolic main reflector and illuminates it directly.

Landscapes

  • Aerials With Secondary Devices (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Claims (8)

1. Antenne à réflecteurs multiples, déstinée à un satellite géostationnaire, comprenant un réflecteur principal parabolique, au moins un réflecteur auxiliaire et plusieurs émetteurs individuels qui émettent, par le réflecteur principal, en direction de différentes zones cibles sur la terre, la totalité des émetteurs individuels étant divisée en plusieurs groupes d'émetteurs formés chacun par des émetteurs individuels voisins, caractérisée en ce qu'à chaque groupe d'émetteurs est associé un réflecteur auxiliaire séparé, sur lequel sont dirigés les émetteurs individuels du groupe et qui réfléchit le rayonnement vers le réflecteur principal, et que les émetteurs individuels de chaque groupe d'émetteurs sont orientés de sorte que des zones cibles voisines soient desservies par des émetteurs individuels de groupes d'émetteurs différents.
2. Antenne à réflecteurs multiples selon la revendication 1, caractérisée en ce que, lors de l'utilisation de trois réflecteurs auxiliaires, les émetteurs individuels sont orientés de telle manière qu'une zone cible quelconque à la surface terrestre soit desservie par un émetteur individuel d'un premier groupe d'émetteurs et soit entourée de façon symétrique de six zones cibles desservies en alternance par les deux autres groupes d'émetteurs, avec la participation au total de trois émetteurs individuels du deuxième groupe et de trois émetteurs du troisième groupe.
3. Antenne à réflecteurs multiples selon la revendication 1 ou 2, caractérisée en ce que les réflecteurs auxiliaires présentent des surfaces réflectrices courbes avec deux foyers, l'un des foyers coïncidant avec le foyer du réflecteur principal, et le groupe d'émetteurs associé étant disposé dans l'autre foyer.
4. Antenne à réflecteurs multiples selon la revendication 3, caractérisée en ce que les surfaces réflectrices des réflecteurs auxiliaires sont des sections d'hyperboloïdes de révolution et/ou d'éllipsoïdes de révolution.
5. Antenne à réflecteurs multiples selon la revendication 3 ou 4, caractérisée en ce que les axes de foyers donnés par les foyers des réflecteurs auxiliaires sont inclinés par rapport à l'axe du réflecteur principal parabolique.
6. Antenne à réflecteurs multiples selon la revendication 5, caractérisée en ce que les axes de foyers de tous les réflecteurs auxiliaires se situent sur une surface latérale de cône qui se forme par rotation des axes de foyers autour de l'axe du réflecteur principal parabolique.
7. Antenne à réflecteurs multiples selon l'une quelconque des revendications 1 à 6, caractérisée en ce que des réflecteurs auxiliaires voisins se recouvrent partiellement et sont sélectifs pour des directions de polarisation ou des gammes de fréquences différentes.
8. Antenne à réflecteurs multiples, déstinée à un satellite géostationnaire, comprenant un réflecteur principal parabolique, au moins un réflecteur auxiliaire et plusieurs émetteurs individuels qui émettent, par le réflecteur principal, en direction de différentes zones cibles sur la terre, la totalité des émetteurs individuels étant divisée en plusieurs groupes d'émetteurs formés chacun par des émetteurs individuels voisins, caractérisée en ce qu'un premier groupe d'émetteurs est disposé au foyer du réflecteur principal parabolique et directement dirigé sur celui-ci, qu'à chaque autre groupe d'émetteurs est associé un réflecteur auxiliaire séparé, sur lequel sont dirigés les émetteurs individuels de ce groupe et qui réfléchit le rayonnement vers le réflecteur principal, et que les émetteurs individuels de chaque groupe d'émetteurs sont orientés de sorte que des zones cibles voisines soient desservies par des émetteurs individuels de groupes d'émetteurs différents.
EP83100957A 1982-02-05 1983-02-02 Antenne à plusieurs réflecteurs Expired EP0086399B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823204029 DE3204029A1 (de) 1982-02-05 1982-02-05 Mehrreflektorantenne
DE3204029 1982-02-05

Publications (2)

Publication Number Publication Date
EP0086399A1 EP0086399A1 (fr) 1983-08-24
EP0086399B1 true EP0086399B1 (fr) 1988-06-22

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP83100957A Expired EP0086399B1 (fr) 1982-02-05 1983-02-02 Antenne à plusieurs réflecteurs

Country Status (2)

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EP (1) EP0086399B1 (fr)
DE (1) DE3204029A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3631735A1 (de) * 1986-09-18 1988-04-07 Messerschmitt Boelkow Blohm Nachrichtenuebertragungseinrichtung fuer raumfahrzeuge

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0028018A1 (fr) * 1979-10-24 1981-05-06 Western Electric Company, Incorporated Système d'antennes du type à réseau à déphasage

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3414904A (en) * 1966-05-16 1968-12-03 Hughes Aircraft Co Multiple reflector antenna
US3914768A (en) * 1974-01-31 1975-10-21 Bell Telephone Labor Inc Multiple-beam Cassegrainian antenna
US3953858A (en) * 1975-05-30 1976-04-27 Bell Telephone Laboratories, Incorporated Multiple beam microwave apparatus
US4090203A (en) * 1975-09-29 1978-05-16 Trw Inc. Low sidelobe antenna system employing plural spaced feeds with amplitude control
US4236161A (en) * 1978-09-18 1980-11-25 Bell Telephone Laboratories, Incorporated Array feed for offset satellite antenna
US4298877A (en) * 1979-01-26 1981-11-03 Solar Energy Technology, Inc. Offset-fed multi-beam tracking antenna system utilizing especially shaped reflector surfaces

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0028018A1 (fr) * 1979-10-24 1981-05-06 Western Electric Company, Incorporated Système d'antennes du type à réseau à déphasage

Also Published As

Publication number Publication date
EP0086399A1 (fr) 1983-08-24
DE3204029A1 (de) 1983-08-11

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