EP0466579B1 - Doppelreflektor mit Gitter - Google Patents

Doppelreflektor mit Gitter Download PDF

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Publication number
EP0466579B1
EP0466579B1 EP19910401907 EP91401907A EP0466579B1 EP 0466579 B1 EP0466579 B1 EP 0466579B1 EP 19910401907 EP19910401907 EP 19910401907 EP 91401907 A EP91401907 A EP 91401907A EP 0466579 B1 EP0466579 B1 EP 0466579B1
Authority
EP
European Patent Office
Prior art keywords
reflector
double
front reflector
grid
stiffeners
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 - Lifetime
Application number
EP19910401907
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English (en)
French (fr)
Other versions
EP0466579A1 (de
Inventor
Jean-Denis Lefebvre
Olivier Lach
Alain Noir
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 Group SAS
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Airbus Group SAS
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Filing date
Publication date
Application filed by Airbus Group SAS filed Critical Airbus Group SAS
Publication of EP0466579A1 publication Critical patent/EP0466579A1/de
Application granted granted Critical
Publication of EP0466579B1 publication Critical patent/EP0466579B1/de
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/22—Reflecting surfaces; Equivalent structures functioning also as polarisation filter
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/001—Crossed polarisation dual antennas

Definitions

  • the present invention relates to a grate bireflector, structure comprising two antenna reflectors, intended for the use of several pairs of radio waves of the same frequency, the waves of a pair being of orthogonal polarizations between them.
  • Antenna systems are known which allow frequency reuse by means of perpendicularly polarized sources and reflectors. Such systems are widely used in the field of satellite applications. For a given frequency, two perpendicularly polarized waves are produced by two separate decoupled sources; this doubles the transmission capacity for the same antenna system, compact and light.
  • the known devices have two reflectors in the form of a parabolic dish.
  • An example of such a device according to the prior art can be seen in FIG. 1, which is also similar to the antenna bireflector described in document GB-A-2 125 633.
  • the first reflector 10 covers the second reflector 12.
  • the cuvettes of the reflectors 10, 12 are for example, each consisting of a honeycomb core formed by a Kevlar fabric (Kevlar is a registered trademark of the EI Dupont Company), sandwiched between two skins, also made of Kevlar.
  • Kevlar is a registered trademark of the EI Dupont Company
  • a grid 14, 16 made of closely spaced parallel conductors which are oriented so that the reflectors reflect waves polarized perpendicularly.
  • the two reflectors 10, 12 are held together by fixing means comprising a peripheral structure 18, for example consisting of a honeycomb core of Kevlar and sandwiched between two Kevlar skins and support ribs 20 formed likewise.
  • Kevlar is chosen for its transparency properties to radio waves. But it is an expensive and difficult material to work: thus obtaining honeycomb structures is long and painful.
  • the known devices have two reflectors provided with different grids.
  • the production of these grids requires very delicate mechanical processes to be implemented.
  • the document FR-A-1 141 476 also describes a system of antennas directed with two reflectors for front and rear, of which the rear reflector, consisting of a single sheet, has no property of selectivity with respect to of the direction of polarization of the radiation to be reflected. This document however does not describe any filtering means between the two reflectors to eliminate any residual component of the polarized radiation intended for the first reflector.
  • the object of the present invention is to overcome these drawbacks: to reduce the cost of manufacturing by reducing the need for Kevlar and simplifying the production of a frequency reuse reflector system using a single reflector provided with a grid, the second reflector does not.
  • the invention recommends the use of a front reflector provided with a grid oriented so as to reflect radio waves linearly polarized in a determined direction of polarization and a rear reflector capable of reflecting radio waves without distinction of polarization .
  • the rear reflector requires only a continuous and reflective surface, without a grid, which can be of less expensive material and having better mechanical characteristics (in particular better rigidity) than Kevlar.
  • the present invention relates to a bireflector according to claim 1.
  • FIG. 2 a schematic representation of an antenna system with a bireflector according to the invention.
  • Two sources S1 and S2 deliver radio signals of the same frequency, linearly polarized and perpendicular to each other. These sources S1 and S2 are arranged on a support 22 which also maintains the bireflector 24.
  • the latter is composed of two reflectors 26, 28, for example in the form of a truncated section of parabola of revolution.
  • the front reflector 26 completely covers the rear reflector 28 and is maintained at a distance determined by assembly means 30. But the overlap of the reflectors 26, 28 can also be partial.
  • the spacing between the reflectors is such that it makes the focal axes of the reflectors parallel to each other without however being confused.
  • the reflectors in the form of a parabola of revolution in the embodiment more particularly shown, are centered and their centers (commonly called vertices) are offset with respect to each other.
  • the front reflector 26 is arranged so as to reflect one of the radio signals (that coming from the source S1 in this example) while it is transparent to the other.
  • the rear reflector 28 is capable of reflecting any radioelectric radiation without distinction of polarization.
  • FIG 3 is a schematic exploded view of a portion of the front reflector.
  • the latter comprises a shell 32 constituted by a honeycomb structure, for example Kevlar or any other material transparent to radio waves and having adequate rigidity qualities.
  • the shell 32 has a thickness eK chosen so as to optimize the radioelectric performance of the bireflector. In the example described and shown, the frequency range from 10 to 14 GHz, the thickness of a Kevlar structure is chosen to be 6.35 mm; in fact, the reflection coefficient of the structure presents approximately a maximum for this value.
  • the shell 32 On its front face, the shell 32 is covered by a skin 34, also made of Kevlar for example.
  • the skin 34 is covered with a grid 36 made of electrical conductors 38 spaced apart so that their projections on a plane perpendicular to the focal axis of the reflector are parallel to each other; moreover, in projection on this plane, the length and the pitch of these conductors are constant.
  • These conductors 38 may for example be copper strips; they are either fixed in a medium transparent to radio frequencies, for example polymides, or directly bonded using an epoxy type glue which does not degas under vacuum.
  • the bireflector comprises a filtering means which makes it possible to eliminate any residual component of the polarized radiation linearly reflected by the front reflector, to avoid its reflection by the rear reflector.
  • the filtering means is composed of a grid 40 of conductors arranged to reflect a linearly polarized radioelectric radiation, parallel to that reflected by the front reflector 26; this grid 40 is supported by the dorsal face of the shell 32 of the front reflector.
  • the projections of the filter conductors in a plane perpendicular to the focal axis of the reflector are parallel to each other and to the projections of the conductors of the front grid 36.
  • This second grid 40 is produced in a similar manner to the front grid 36.
  • a second skin 42 for example made of Kevlar, covers the filtering grid 40.
  • the filtering grid 40 introduces a certain symmetry into the structure of the front reflector 26, which has the advantage of improving its resistance. mechanical and its rigidity.
  • the radioelectric radiation emitted by the source S1 is therefore completely reflected by the front reflector 26.
  • the latter is almost transparent (by construction: choice of materials, positioning of the grids) to the radiation emitted by the source S2 which is reflected by the rear reflector.
  • Figure 4 is a schematic exploded view of a portion of the rear reflector. This one is able to reflect any radioelectric radiation independently of its polarization: it suffices to present a continuous surface reflecting the radio waves. It can therefore be produced without a grid and in less expensive materials, easier to work with, and having better thermomechanical characteristics than Kevlar.
  • the rear reflector 28 consists of a shell 44, having a honeycomb structure of conductive material, for example aluminum, sandwiched between two identical skins 46, each made of four layers 48, for example of carbon fibers.
  • the shell 44 has a thickness eA chosen so as to ensure good thermomechanical behavior of the bireflector.
  • the thickness eA is for example chosen, for an aluminum shell, in a range going from 20 to 40 mm. In the example described, eA is equal to 25 mm.
  • the number of layers 48 making up the skins 46 is also chosen to ensure good thermomechanical behavior of the assembly.
  • the orientation of the carbon fibers of each layer 48 is chosen so as to ensure on the one hand, the mechanical strength of the reflector, but also so that the latter has a coefficient of expansion substantially zero at operating temperatures.
  • Figure 5 shows schematically the assembly means joining the reflectors to each other.
  • This assembly means maintains the spacing between the reflectors. This spacing varies, depending on the position on the circumference of a reflector, from a minimum spacing to a maximum spacing, diametrically opposite.
  • the assembly means consists of a peripheral structure 50, two internal stiffeners 52 in the form of mutually parallel support ribs and spacers 54. These elements are held on the reflector rear 28 by bonding on shims 56, for example made of Kevlar or any other material transparent to radio waves and having the required thermomechanical properties, fixed to the rear reflector.
  • the shims 56 are for example fixed to the rear reflector by mechanical fixing means (not shown) which may or may not be removable.
  • the shims 56 are distributed along the peripheral structure on either side of the internal stiffeners 52 and the spacers 54.
  • the elements constituting the assembly means are bonded using an insulating adhesive which is not loaded on the dorsal face of the front reflector 26.
  • the peripheral structure 50 is made of honeycomb, for example Kevlar.
  • the internal stiffeners 52 also have a honeycomb structure, for example Kevlar. They are perforated so as to reduce their mass. They are arranged so as to disturb the radiation pattern of the reflectors as little as possible.
  • the projection PR of the stiffeners 52 on a plane P perpendicular to the focal axes AF of the reflectors is parallel to the projections PC of the conductors of the grids 38 of the front reflector 26.
  • the projection PR of the stiffeners 52 on the plane P perpendicular to the focal axes AF of the reflectors is perpendicular to the projections PC of the conductors of the grids 38 of the front reflector 26.
  • stiffeners 52 are fixed perpendicular to the dorsal face of the front reflector 26.
  • spacers 54 made of Kevlar or any other material transparent to radio waves and having the required rigidity. These spacers 54 are for example arranged at regular intervals, on an axis parallel to the internal stiffeners 52 and passing through the top of the rear reflector. The spacers 54 fixed to each of the reflectors reduce the thermomechanical deformations of the front reflector by stress by resting on the rear reflector which has a substantially zero coefficient of expansion.
  • a bi-reflector according to the invention thanks to the use of a rear reflector capable of reflecting any radio wave independently of its polarization makes it possible to simplify the construction of the assembly and to reduce costs. On the other hand, the materials used make it possible to obtain better thermomechanical stability of the assembly.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)

Claims (8)

  1. Antennen-Doppelreflektor, welcher:
    - einen vorderen Reflektor (26) umfaßt, der aus einem Körper (32) zusammengesetzt ist, welcher ein Gitter (36) von Leitern (38) unterstützt, das für die Reflexion einer linear polarisierten radioelektrischen Strahlung angeordnet ist,
    - einen hinteren Reflektor (28) umfaßt, der fähig ist, eine radioelektrische Strahlung ohne Unterscheidung der Polarisation zu reflektieren,
    - eine Montagevorrichtung (30) umfaßt, die fähig ist, den vorderen Reflektor (26) auf einen bestimmten Abstand vom hinteren Reflektor (28) zu halten, wobei der vordere Reflektor (26) zumindest teilweise den hinteren Reflektor (28) überlappt,
    dadurch gekennzeichnet, daß er ein Filtergerät (40) umfaßt, das zwischen dem vorderen Reflektor (26) und dem hinteren Reflektor (28) angeordnet ist und das fähig ist, alle zurückbleibenden Bestandteile der linear polarisierten Strahlung zu beseitigen, die durch den vorderen Reflektor (26) reflektiert werden, wobei das besagte Filtergerät (40) aus einem Gitter von Leitern gebildet wird, die angeordnet sind, um eine parallel linear polarisierte radioelektrische Strahlung auf die durch den vorderen Reflektor (26) reflektierte zu reflektieren, und daß der hintere Reflektor (28) eine wabenförmige Struktur (44) umfaßt, die zwischen zwei Außenschichten (46) geschichtet wird, von denen zumindest eine aus leitfähigem Material ist.
  2. Doppelreflektor gemäß Anspruch 1, dadurch gekennzeichnet, daß das Gitter zur Filterung durch die Rückwand des Körpers (32) des vorderen Reflektors (26) gestützt wird.
  3. Doppelreflektor gemäß Anspruch 1, dadurch gekennzeichnet, daß der hintere Reflektor (28) einen Wärmedehnungskoeffizienten genau gleich Null hat.
  4. Doppelreflektor gemäß Anspruch 1, dadurch gekennzeichnet, daß die besagte wabenförmige Struktur (44) des hinteren Reflektors eine Dicke (eA) aufweist, die gewählt wird, um eine thermomechanische Widerstandsfähigkeit des Doppelreflektors zu optimieren.
  5. Doppelreflektor gemäß Anspruch 4, dadurch gekennzeichnet, daß die besagte wabenförmige Struktur (44) aus Aluminium ist, die Dicke (eA) ist in einem Bereich zwischen 20 und 40 mm eingeschlossen.
  6. Doppelreflektor gemäß Anspruch 1, wobei die Montagevorrichtung (30), die einerseits an der Rückseite des vorderen Reflektors und andererseits an der Vorderseite des hinteren Reflektors befestigt ist, eine Struktur um den Umfang (50) und mindestens zwei innere Versteifungen (52) in Form von Stützrippen umfaßt, dadurch gekennzeichnet, daß die Montagevorrichtung außerdem ein Gerät (54) umfaßt, um Deformationen des vorderen Reflektors aufgrund von Temperaturschwankungen zu kompensieren, wobei das besagte Gerät zur Kompensation der Deformationen Stege (54) aus für radioelektrische Wellen quasi-durchlässigem Material umfaßt, wobei jeder dieser Stege (54) einerseits an der Rückseite des vorderen Reflektors und andererseits an der Vorderseite des hinteren Reflektors befestigt ist.
  7. Doppelreflektor gemäß Anspruch 6, dadurch gekennzeichnet, daß die besagten inneren Versteifungen (52) eine Projektion (PR) auf eine Ebene (P) senkrecht zu den Brennachsen (AF) der Reflektoren (26, 28) aufweisen, wobei diese Projektion parallel zu den Projektionen (PC) der Leiter (38) des Gitters (36) des vorderen Reflektors (26) ist und daß die Versteifungen (52) senkrecht zur Rückseite des vorderen Reflektors (26) befestigt sind.
  8. Doppelreflektor gemäß Anspruch 6, dadurch gekennzeichnet, daß die besagten inneren Versteifungen (52) eine Projektion (PR) auf eine Ebene (P) senkrecht zu den Brennachsen (AF) der Reflektoren (26, 28) aufweisen, wobei diese Projektion senkrecht zu den Projektionen (PC) der Leiter (38) des Gitters (36) des vorderen Reflektors (26) ist und daß die Versteifungen (52) senkrecht an der Rückseite des vorderen Reflektors (26) befestigt sind.
EP19910401907 1990-07-11 1991-07-09 Doppelreflektor mit Gitter Expired - Lifetime EP0466579B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9008828A FR2664750B1 (fr) 1990-07-11 1990-07-11 Bireflecteur a grilles.
FR9008828 1990-07-11

Publications (2)

Publication Number Publication Date
EP0466579A1 EP0466579A1 (de) 1992-01-15
EP0466579B1 true EP0466579B1 (de) 1995-01-04

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ID=9398599

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910401907 Expired - Lifetime EP0466579B1 (de) 1990-07-11 1991-07-09 Doppelreflektor mit Gitter

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EP (1) EP0466579B1 (de)
JP (1) JP3208154B2 (de)
DE (1) DE69106443T2 (de)
ES (1) ES2067178T3 (de)
FR (1) FR2664750B1 (de)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2709380B1 (fr) * 1993-08-23 1995-09-22 Alcatel Espace Antenne bi-faisceaux à balayage électronique.
FR2719162B1 (fr) * 1994-04-20 1996-12-06 Henri Sadones Antenne de faisceau hertzien à au moins deux directions de réflexion.
DE19713735C1 (de) * 1997-04-03 1998-08-20 Daimler Benz Aerospace Ag Verfahren zur Herstellung von polarisationsselektiven Reflektoren
SE0100345D0 (sv) * 2001-02-02 2001-02-02 Saab Ab Antennsystem och reflektorelement i antennsystem
JP5305994B2 (ja) * 2009-03-12 2013-10-02 三菱電機株式会社 アンテナ装置
DE202009003501U1 (de) * 2009-03-13 2009-05-20 Hps High Performance Space Structure Systems Gmbh Reflektorsystem für eine polarisationsselektive Antenne mit doppelt linearer Polarisation
US9214736B2 (en) * 2012-07-25 2015-12-15 Orbital Sciences Corporation Systems and methods for mitigating disturbances in a dual gridded reflector antenna

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH326809A (de) * 1954-11-11 1957-12-31 Patelhold Patentverwertung Richtantennensystem mit Umlenkspiegeln
FR2412961A1 (fr) * 1977-12-22 1979-07-20 Thomson Csf Systeme d'antenne a balayage conique pour radar de poursuite
FR2488058A1 (fr) * 1980-07-29 1982-02-05 Thomson Csf Source rayonnante bi-bande compacte fonctionnant dans le domaine des hyperfrequences
US4575726A (en) * 1982-08-16 1986-03-11 Rca Corporation Antenna construction including two superimposed polarized parabolic reflectors

Also Published As

Publication number Publication date
DE69106443D1 (de) 1995-02-16
JPH04253404A (ja) 1992-09-09
DE69106443T2 (de) 1995-08-10
EP0466579A1 (de) 1992-01-15
JP3208154B2 (ja) 2001-09-10
FR2664750B1 (fr) 1993-01-29
FR2664750A1 (fr) 1992-01-17
ES2067178T3 (es) 1995-03-16

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