EP0088681A1 - Dual-reflector antenna with incorporated polarizer - Google Patents

Dual-reflector antenna with incorporated polarizer Download PDF

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Publication number
EP0088681A1
EP0088681A1 EP83400424A EP83400424A EP0088681A1 EP 0088681 A1 EP0088681 A1 EP 0088681A1 EP 83400424 A EP83400424 A EP 83400424A EP 83400424 A EP83400424 A EP 83400424A EP 0088681 A1 EP0088681 A1 EP 0088681A1
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EP
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Prior art keywords
panels
diodes
reflector
auxiliary reflector
wires
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EP83400424A
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German (de)
French (fr)
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EP0088681B1 (en
Inventor
Albert Dupressoir
François Salvat
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Thales SA
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Thomson CSF SA
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    • 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
    • H01Q19/195—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 wherein a reflecting surface acts also as a polarisation filter or a polarising device

Definitions

  • the present invention relates to antennas for transmitting or receiving microwave waves and more particularly antennas with double reflector of the Cassegrain or Gregori type comprising a concave main reflector of generally parabolic shape, a convex auxiliary reflector, of generally hyperbolic shape and a source microwave, these three elements being thus arranged with respect to each other that the convex auxiliary reflector returns to the main reflector the radiation emitted by the source.
  • a radio wave has an elliptical polarization which, at the limit, can be linear or circular.
  • a detection system radar
  • the targets sought have a low equivalent surface in circular polarization it may be useful to switch to linear polarization.
  • a solution usually used consisted in providing a polarizer in front of the opening of the source, this polarizer being with blades or 'with wires and being able to be retracted mechanically to modify the polarization; but the retraction is difficult for mechanical reasons and especially for reasons of congestion of the retraction system because this system must be located in front of the reflectors and then constitutes a mask detrimental to the proper functioning of the antenna.
  • curved panels of diode wires immediately in front of the auxiliary reflector allowing electrical polarization switching. More precisely, curved dielectric panels having a shape substantially identical to that of the auxiliary reflector and a surface substantially equal to that of the latter are placed in front of the auxiliary reflector, these panels serving to support wire-diodes matching the hyperbolic shape of the panels. ; a controlled supply circuit is placed behind the auxiliary reflector and is connected to the diode wires to ensure either direct polarization of the diodes either an absence of polarization or a reverse polarization such that the diodes are blocked.
  • the switchable polarizer according to the invention operates on reflection and not on transmission: it is crossed once by an incident wave from the source, which is therefore subject to polarization. partial, and another time after reflection of this partially polarized wave on the auxiliary reflector.
  • Such a panel is essentially constituted by a dielectric plate in the thickness of which is embedded a network of conductive wires parallel to each other and separated by a distance of the order of a fraction of wavelength.
  • Each wire is actually made up of a succession of sections of wire separated by diodes all oriented in the same direction and the sections have a length of the order of a fraction of length. wave.
  • the sections of wires are isolated from each other.
  • the impedance presented by the network is then capacitive and causes a phase delay of the electric field component parallel to the wires.
  • the wires behave like continuous conductors and not like isolated sections.
  • the impedance presented by the network is inductive and causes a phase advance of the electric field component parallel to the wires.
  • the polarization switching of the microwave wave is done by controlling the power supply of the son-diodes.
  • the present invention proposes to apply this basic principle of polarization switching to a Cassegrain type antenna, by providing on the one hand that panels of wire-diodes are placed immediately in front of the hyperbolic auxiliary reflector, while their system of power supply and control is placed behind this reflector, and on the other hand that the panels supporting the son-diodes and the son-diodes themselves have a curved shape matching the shape of the surface of the auxiliary reflector.
  • a Cassegrain antenna according to the invention is shown in Figure 1.
  • concave main reflector 1 of generally parabolic shape (paraboloid of revolution) and a convex auxiliary reflector 2 of generally hyperbolic shape (hyperbolold of revolution) of dimension much smaller than the main reflector 1 (for example a diameter approximately ten times smaller).
  • a multimode excitation source 3 is placed at the top of the main reflector 1 and emits microwave waves towards the auxiliary reflector 2, which is kept centered in front of the source and coaxially to the main reflector by four rigid tie rods 4 of small diameter arranged. in planes 45 ° from the axis of the reflectors.
  • Microwave power supply circuits designated by the reference 5 are placed behind the source 3, behind the main reflector 1.
  • the controlled polarizer, 7, which comprises for example three sets 8, 9, 10, of double arrays of wire-diodes: each set comprises both a layer of diode wires parallel generally oriented in a given direction and a layer of. diode wires oriented perpendicular to those of the other layer.
  • control circuits 12 are placed making it possible to supply the diodes of the various networks directly or in reverse, and control circuits 13 making it possible to check and know the state of good or bad operation diodes (breaks or short circuits), therefore that of the polarization assembly.
  • circuits are connected to the son-diodes by conductors 14, 15 passing through holes 17 of small diameter drilled near the edge of the reflector 2.
  • the circuits 12 and 13 are placed in a sealed box 16 whose dimensions are such that it does not disturb the radiation of the antenna when it is placed behind the auxiliary reflector 2.
  • the supply voltages of the diodes, the control orders, the control signals are conveyed by cables 18, 19 passing inside the tie rods 4 and coming from a control unit 11.
  • Figure 2 shows the construction detail of the electronically controlled polarizer placed in front of the auxiliary reflector 2.
  • These three panels 21, 22, 23 are separated by spacers which define their spacing and they all have the. same substantially hyperbolic shape as the surface- 6 of the auxiliary reflector 2.
  • the spacing of the panels, the thickness of each of them influence the polarization undergone by the microwave wave.
  • the assemblies 8, 9 and 10 are all constituted in the same way, that is to say each with three panels such as 21, 22, 23 and they are separated by spacers 24.
  • FIG. 3 represents a detail of embodiment of a panel 21 or 23, in cross section and in top view.
  • the curved panel is made of a dielectric material and is provided with parallel grooves 25 for the wire-diodes, these grooves being wide enough to contain the diodes 26 connected by sections of wire 27.
  • the wire-diodes, thus formed and maintained in the grooves 25 follow the curved shape of the panels 21 and 23.
  • the diode wires which are parallel to each other can be separated by a distance of the order of half the wavelength of the radiation emitted, while the spacing between a diode wire and its supply wire would be of the order of tenth of the wavelength.
  • the panels can be made by molding directly giving the desired curved farm with the parallel grooves.
  • the son-diodes are then put in place, after which the panneat; are assembled together, for example by strapping and fixed to the auxiliary reflector.
  • the Cassegrain antenna which has just been described can be used in particular in tracking and ecartometry radar systems, trajectography, spatial listening, etc.

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Abstract

1. Radar antenna of double reflector-type comprising a generally parabolic main reflector (1) and a generally hyperbolic auxiliary reflector (2) characterized by the fact that it comprises, located in front of the hyperbolic auxiliary reflector (2), polarization switch comprising dielectric panels (7) having a surface substantially equal to that of the auxiliary reflector (2) and a contour substantially identical to that of the latter, these panels carrying diode wires (26, 27) following the hyperbolic shape of these panels, a controlled feed circuit (12) being located behind the auxiliary reflector (2) and connected to the diode wires of the different panels (21, 23) to feed the diode wires in one of two possible states which are a state where the diodes are blocked and a state where they are forward biased and thus conducting, respectively.

Description

La présente invention concerne les antennes d'émission ou réception d'ondes hyperfréquences et plus particulièrement les antennes à double réflecteur de type Cassegrain ou Gregori comportant un réflecteur principal concave de forme généralement parabolique, un réflecteur auxiliaire convexe, de forme généralement hyperbolique et une source hyperfréquence, ces trois éléments étant ainsi disposés les uns par rapport aux autres que le réflecteur auxiliaire convexe renvoie vers le réflecteur principal le rayonnement émis par la source.The present invention relates to antennas for transmitting or receiving microwave waves and more particularly antennas with double reflector of the Cassegrain or Gregori type comprising a concave main reflector of generally parabolic shape, a convex auxiliary reflector, of generally hyperbolic shape and a source microwave, these three elements being thus arranged with respect to each other that the convex auxiliary reflector returns to the main reflector the radiation emitted by the source.

Il est souhaitable, lorsqu'on émet une onde radioélectrique, de pouvoir modifier les caractéristiques de polarisation de l'onde émise.It is desirable, when transmitting a radio wave, to be able to modify the polarization characteristics of the transmitted wave.

D'une manière très générale, une onde radio-électrique possède une polarisation elliptique qui, à la limite, peut être linéaire ou circulaire. Lorsqu'on utilise cette onde dans un système de détection (radar), il est parfois intéressant de passer d'une polarisation linéaire à une polarisation circulaire pour éliminer les échos dus à la pluie. Dans le cas d'émission en présence de brouillage, il peut être intéressant d'inverser la polarisation circulaire. Enfin, lorsque les cibles recherchées ont une surface équivalente faible en polarisation circulaire, il peut être utile de passer en polarisation linéaire.Generally speaking, a radio wave has an elliptical polarization which, at the limit, can be linear or circular. When using this wave in a detection system (radar), it is sometimes interesting to switch from a linear polarization to a circular polarization to eliminate the echoes due to rain. In the case of transmission in the presence of interference, it may be advantageous to reverse the circular polarization. Finally, when the targets sought have a low equivalent surface in circular polarization, it may be useful to switch to linear polarization.

Ces exemples montrent l'intérêt de disposer de transformateurs de polarisation au niveau de l'émission ou de la réception de l'onde radioélectrique.These examples show the advantage of having polarization transformers at the level of the emission or the reception of the radio wave.

Dans le cas des antennes de type Cassegrain, on n'a pas cependant trouvé jusqu'à maintenant de solution satisfaisante pour disposer d'une commutation de polarisation pouvant servir efficacement dans les cas mentionnés ci-dessus.In the case of Cassegrain type antennas, however, no satisfactory solution has so far been found for having polarization switching which can be used effectively in the cases mentioned above.

En effet, une solution habituellement utilisée consistait à prévoir un polarisateur devant l'ouverture de la source, ce polariseur étant à lames ou' à fils et pouvant être escamoté mécaniquement pour modifier la polarisation ; mais l'escamotage est difficile pour des raisons mécaniques et surtout des raisons d'encombrement du système d'escamotage car ce système doit se situer devant les réflecteurs et constitue alors un masque préjudiciable au bon fonctionnement de l'antenne.In fact, a solution usually used consisted in providing a polarizer in front of the opening of the source, this polarizer being with blades or 'with wires and being able to be retracted mechanically to modify the polarization; but the retraction is difficult for mechanical reasons and especially for reasons of congestion of the retraction system because this system must be located in front of the reflectors and then constitutes a mask detrimental to the proper functioning of the antenna.

On a également imaginé de placer devant l'ouverture de la source un transformateur de polarisation à commutation électrique, constitué de panneaux plans de fils-diodes parallèles pouvant être rendus conducteurs et donc continus par polarisation directe des diodes, ou non conducteurs et donc discontinus par polarisation inverse ou absence de polarisation des diodes, l'état continu ou discontinu des fils influençant la polarisation de l'onde émise ; mais il s'avère qu'il existe un problème de tenue en puissance de ces panneaux qui reçoivent une grande densité de puissance électromagnétique du fait qu'ils sont placés immédiatement devant l'ouverture de la source ; d'autre part, d'un point de vue pratique, il est difficile de trouver un emplacement convenable pour les circuits d'alimentation des fils-diodes.It has also been imagined to place an electrical switching polarization transformer in front of the source opening, consisting of flat panels of parallel wire-diodes which can be made conductive and therefore continuous by direct polarization of the diodes, or non-conductive and therefore discontinuous by reverse polarization or absence of polarization of the diodes, the continuous or discontinuous state of the wires influencing the polarization of the emitted wave; but it turns out that there is a problem of power handling of these panels which receive a high density of electromagnetic power because they are placed immediately before the opening of the source; on the other hand, from a practical point of view, it is difficult to find a suitable location for the supply circuits of the son-diodes.

On a aussi proposé de placer un polariseur dans la source, en milieu guidé, c'est-à-dire dans le cornet dont l'ouverture est - dirigée vers le réflecteur auxiliaire ; par exemple des lames quart-d'onde inclinées à 45° permettent de créer une polarisation linéaire ; mais outre qu'il existe une difficulté de modification de la polarisation, on constate aussi que ce genre de dispositif présente l'inconvénient, notamment en émission multimode, d'engendrer des modes supérieurs non désirés.It has also been proposed to place a polarizer in the source, in a guided medium, that is to say in the horn whose opening is - directed towards the auxiliary reflector; for example quarter-wave plates inclined at 45 ° make it possible to create a linear polarization; but apart from the fact that there is a difficulty in modifying the polarization, it is also observed that this type of device has the drawback, in particular in multimode transmission, of generating unwanted higher modes.

Pour éviter ces inconvénients, on propose selon l'invention de disposer immédiatement devant le réflecteur auxiliaire des panneaux galbés de fils-diodes permettant une commutation électrique de polarisation. Plus précisément, on place devant le réflecteur auxiliaire des panneaux diélectriques galbés ayant une forme sensiblement identique à celle du réflecteur auxiliaire et une surface sensiblement égale à celle de ce dernier, ces panneaux servant de support à des fils-diodes épousant la forme hyperbolique des panneaux ; un circuit d'alimentation commandée est placé derrière le réflecteur auxiliaire et est relié aux fils diode pour assurer soit une polarisation directe des diodes soit une absence de polarisation ou une polarisation inverse telle que les diodes soient bloquées.To avoid these drawbacks, it is proposed according to the invention to have curved panels of diode wires immediately in front of the auxiliary reflector allowing electrical polarization switching. More precisely, curved dielectric panels having a shape substantially identical to that of the auxiliary reflector and a surface substantially equal to that of the latter are placed in front of the auxiliary reflector, these panels serving to support wire-diodes matching the hyperbolic shape of the panels. ; a controlled supply circuit is placed behind the auxiliary reflector and is connected to the diode wires to ensure either direct polarization of the diodes either an absence of polarization or a reverse polarization such that the diodes are blocked.

La construction de ces panneaux est plus complexe que celle de panneaux plans de fils-diodes utilisés jusqu'à maintenant comme commutateurs de polarisation agissant à la sortie de la source, mais elle permet d'éliminer les inconvénients des dispositifs de polarisation utilisés jusqu'à maintenant, et ceci sans altérer les performances de l'antenne.The construction of these panels is more complex than that of flat wire-diode panels used until now as polarization switches acting at the output of the source, but it makes it possible to eliminate the drawbacks of the polarization devices used up to now, without affecting the performance of the antenna.

A la différence des polariseurs habituellement utilisés dans les antennes de type Cassegrain, le polariseur commutable selon l'invention fonctionne à la réflexion et non à la transmission : il est traversé une fois par une onde incidente issue de la source, qui subit ainsi une polarisation partielle, et une autre fois après réflexion de cette onde partiellement polarisée sur le réflecteur auxiliaire.Unlike the polarizers usually used in Cassegrain type antennas, the switchable polarizer according to the invention operates on reflection and not on transmission: it is crossed once by an incident wave from the source, which is therefore subject to polarization. partial, and another time after reflection of this partially polarized wave on the auxiliary reflector.

D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description qui suit et qui est faite en référence aux dessins annexés dans lesquels :

  • - la figure 1 représente schématiquement, en coupe transversale, une antenne de type Cassegrain selon l'invention,
  • - la figure 2 représente plus en détail le réflecteur auxiliaire, montrant les panneaux superposés de fils- diodes,
  • - la figure 3 montre un détail un détail de réalisation d'un panneau de fils-diodes,
Other characteristics and advantages of the invention will appear on reading the description which follows and which is given with reference to the appended drawings in which:
  • FIG. 1 schematically represents, in cross section, a Cassegrain type antenna according to the invention,
  • FIG. 2 represents in more detail the auxiliary reflector, showing the superimposed panels of son-diodes,
  • FIG. 3 shows a detail a detail of an embodiment of a panel of wire-diodes,

On pourra se référer au brevet français 2 382 109 du 25 février 1977 pour des explications complémentaires relatives à la possibilité d'effectuer une commutation électrique de polarisation d'une onde hyperfréquence au moyen d'un panneau plan de fils-diodes placé sur le trajet d'une onde.Reference may be made to French patent 2,382,109 of February 25, 1977 for further explanations relating to the possibility of effecting an electrical polarization switching of a microwave wave by means of a flat panel of son-diodes placed on the path. of a wave.

Un tel panneau est essentiellement constitué par une plaque diélectrique dans l'épaisseur de laquelle est noyé un réseau de fils conducteurs parallèles entre eux et séparés par une distance de l'ordre d'une fraction de longueur d'onde. Chaque fil est en réalité constitué d'une succession de tronçons de fils séparés par des diodes toutes orientées dans le même sens et les tronçons ont une longueur de l'ordre d'une fraction de longueur d'onde.Such a panel is essentially constituted by a dielectric plate in the thickness of which is embedded a network of conductive wires parallel to each other and separated by a distance of the order of a fraction of wavelength. Each wire is actually made up of a succession of sections of wire separated by diodes all oriented in the same direction and the sections have a length of the order of a fraction of length. wave.

En l'absence de polarisation des diodes ou en présence d'une polarisation inverse, les tronçons de fils sont isolés les uns des autres. L'impédance présentée par le réseau est alors capacitive et provoque un retard de phase de la composante de champ électrique parallèle aux fils. Au contraire, en présence d'une polarisation directe des diodes en série, les fils se comportent comme des conducteurs continus et non comme des tronçons isolés. L'impédance présentée par le réseau est inductive et provoque une avance de phase de la composante de champ électrique parallèle aux fils. Selon le nombre de diodes, on peut obtenir plusieurs valeurs de déphasage et il peut être nécessaire de prévoir plusieurs panneaux parallèles ayant éventuellement des orientations de fils différentes.In the absence of polarization of the diodes or in the presence of a reverse polarization, the sections of wires are isolated from each other. The impedance presented by the network is then capacitive and causes a phase delay of the electric field component parallel to the wires. On the contrary, in the presence of a direct polarization of the diodes in series, the wires behave like continuous conductors and not like isolated sections. The impedance presented by the network is inductive and causes a phase advance of the electric field component parallel to the wires. Depending on the number of diodes, it is possible to obtain several phase shift values and it may be necessary to provide several parallel panels possibly having different wire orientations.

La commutation de polarisation de l'onde hyperfréquence se fait par commande de l'alimentation des fils-diodes.The polarization switching of the microwave wave is done by controlling the power supply of the son-diodes.

La présente invention propose d'appliquer ce principe de base de commutation de polarisation à une antenne de type Cassegrain, en prévoyant d'une part que des panneaux de fils-diodes sont placés immédiatement devant le réflecteur auxiliaire hyperbolique, tandis que leur système d'alimentation et de commande est placé derrière ce réflecteur, et d'autre part que les panneaux supportant les fils-diodes et les fils-diodes eux-mêmes ont une forme galbée épousant la forme de la surface du réflecteur auxiliaire.The present invention proposes to apply this basic principle of polarization switching to a Cassegrain type antenna, by providing on the one hand that panels of wire-diodes are placed immediately in front of the hyperbolic auxiliary reflector, while their system of power supply and control is placed behind this reflector, and on the other hand that the panels supporting the son-diodes and the son-diodes themselves have a curved shape matching the shape of the surface of the auxiliary reflector.

Une antenne Cassegrain selon l'invention est représentée à la figure 1.A Cassegrain antenna according to the invention is shown in Figure 1.

Elle comprend un réflecteur principal concave 1, de forme généralement parabolique (paraboloide de révolution) et un réflecteur auxiliaire convexe 2 de forme généralement hyperbolique (hyperbololde de révolution) de dimension beaucoup plus petite que le réflecteur principal 1 (par exemple un diamètre environ dix fois plus petit).It comprises a concave main reflector 1, of generally parabolic shape (paraboloid of revolution) and a convex auxiliary reflector 2 of generally hyperbolic shape (hyperbolold of revolution) of dimension much smaller than the main reflector 1 (for example a diameter approximately ten times smaller).

Une source excitatrice multimode 3 est placée au sommet du réflecteur principal 1 et émet des ondes hyperfréquences vers le réflecteur auxiliaire 2, lequel est maintenu centré devant la source et coaxialement au réflecteur principal par quatre tirants rigides 4 de faible diamètre disposés. dans des plans à 45° de l'axe des réflecteurs.A multimode excitation source 3 is placed at the top of the main reflector 1 and emits microwave waves towards the auxiliary reflector 2, which is kept centered in front of the source and coaxially to the main reflector by four rigid tie rods 4 of small diameter arranged. in planes 45 ° from the axis of the reflectors.

Des circuits d'alimentation hyperfréquence désignés par la référence 5 sont placés derrière la source 3, à l'arrière du réflecteur principal 1.Microwave power supply circuits designated by the reference 5 are placed behind the source 3, behind the main reflector 1.

Immédiatement en avant de la surface réfléchissante 6 du reflecteur auxiliaire est placé le polarisateur commandé, 7, qui comporte par exemple trois ensembles 8, 9, 10, de réseaux doubles de fils-diodes : chaque ensemble comporte à la fois une couche de fils diodes parallèles orientés globalement dans une direction donnée et une couche de. fils-diode orientés perpendiculairement à ceux de l'autre couche.Immediately in front of the reflecting surface 6 of the auxiliary reflector is placed the controlled polarizer, 7, which comprises for example three sets 8, 9, 10, of double arrays of wire-diodes: each set comprises both a layer of diode wires parallel generally oriented in a given direction and a layer of. diode wires oriented perpendicular to those of the other layer.

Le détail des ensembles de réseaux de fils-diode sera donné plus loin.The details of the sets of wire-diode networks will be given later.

En arrière du réflecteur auxiliaire 2, sont placés des circuits de commande 12 permettant d'alimenter les diodes des différents réseaux en direct ou en inverse, et des circuits de contrôle 13 permettant de vérifier et de connaître l'état de bon ou de mauvais fonctionnement des diodes (coupures ou court- circuit) donc celui de l'ensemble de polarisation.Behind the auxiliary reflector 2, control circuits 12 are placed making it possible to supply the diodes of the various networks directly or in reverse, and control circuits 13 making it possible to check and know the state of good or bad operation diodes (breaks or short circuits), therefore that of the polarization assembly.

Ces circuits sont reliés aux fils-diodes par des conducteurs 14, 15 passant à travers des trous 17 de faible diamètre percés près du bord du réflecteur 2.These circuits are connected to the son-diodes by conductors 14, 15 passing through holes 17 of small diameter drilled near the edge of the reflector 2.

Les circuits 12 et 13 sont placés dans un caisson étanche 16 dont les dimensions sont telles qu'il ne perturbe pas le rayonnement de l'antenne lorsqu'il est placé à l'arrière du réflecteur auxiliaire 2.The circuits 12 and 13 are placed in a sealed box 16 whose dimensions are such that it does not disturb the radiation of the antenna when it is placed behind the auxiliary reflector 2.

Les tensions d'alimentation des diodes, les ordres de commande, les signaux de contrôle sont véhiculés par des câbles 18, 19 passant à l'intérieur des tirants 4 et provenant d'un boîtier de commande 11.The supply voltages of the diodes, the control orders, the control signals are conveyed by cables 18, 19 passing inside the tie rods 4 and coming from a control unit 11.

La figure 2 mòntre le détail de réalisation du polari- seur à commande électronique placé devant le réflecteur auxiliaire 2.Figure 2 shows the construction detail of the electronically controlled polarizer placed in front of the auxiliary reflector 2.

Les trois ensembles 8, 9, 10 de réseaux de fils diodes sont protégés par un radome .20 de faible épaisseur et sons: constitués chacun de préférence par trois panneaux qui sont respectivement :

  • - un panneau 21 de fils-diodes noyés dans un diélectrique,
  • ― un panneau- diélectrique 22 servant au réglage de l'adaptation des réseaux de fils diodes entre eux,
  • un panneau 23 de-fils diodes qui peuvent être orientés différemment de ceux du panneau. 21.
The three sets 8, 9, 10 of networks of diode wires are protected by a thin .20 radome and sound: each preferably made up of three panels which are respectively:
  • a panel 21 of wire-diodes embedded in a dielectric,
  • A dielectric panel 22 used for adjusting the adaptation of the networks of diode wires between them,
  • a panel 23 of diode wires which can be oriented differently from those of the panel. 21.

Ces trois panneaux 21, 22, 23 sont séparés par des entretoises qui définissent leur espacement et ils ont tous la. même forme sensiblement hyperbolique que la surface- 6 du réflecteur auxiliaire 2. L'espacement des panneaux, l'épaisseur de chacun d'eux influent sur la polarisation subie par l'onde hyperfréquence.These three panels 21, 22, 23 are separated by spacers which define their spacing and they all have the. same substantially hyperbolic shape as the surface- 6 of the auxiliary reflector 2. The spacing of the panels, the thickness of each of them influence the polarization undergone by the microwave wave.

Les ensembles 8, 9 et 10 sont tous constitués de la même manière, c'est-à-dire chacun avec trois panneaux tels que 21, 22, 23 et ils sont séparés par des entretoises 24.The assemblies 8, 9 and 10 are all constituted in the same way, that is to say each with three panels such as 21, 22, 23 and they are separated by spacers 24.

La figure 3 représente un détail de réalisation d'un panneau 21 ou 23, en coupe transversale et en vue de- dessus. Le panneau galbé est réalisé en un matériau diélectrique et est pourvu de rainures parallèles 25 pour les fils-diodes, ces rainures étant assez larges pour contenir les diodes 26 reliées par des tronçons de fils 27. Les fils-diodes, ainsi constitués et maintenus dans les rainures 25, épousent la forme galbée des panneaux 21 et 23.FIG. 3 represents a detail of embodiment of a panel 21 or 23, in cross section and in top view. The curved panel is made of a dielectric material and is provided with parallel grooves 25 for the wire-diodes, these grooves being wide enough to contain the diodes 26 connected by sections of wire 27. The wire-diodes, thus formed and maintained in the grooves 25 follow the curved shape of the panels 21 and 23.

D'autres rainures 28, plus petites que les rainures 25 et parallèles à ces dernières, servent à maintenir des fils d'alimentation 29 pour les fils-diodes.Other grooves 28, smaller than the grooves 25 and parallel to the latter, serve to hold supply wires 29 for the wire-diodes.

Les fils diodes parallèles entre eux peuvent être séparés par une distance de l'ordre de la demi-longueur d'onde du rayonnement émis, tandis que l'espacement entre un fil-diode et son fil d'alimentation serait de l'ordre du dixième de la longueur d'onde. Les panneaux peuvent être réalisés par moulage donnant directement la ferme galbée désirée avec les rainures paralleles. Les fils-diodes sont alors mis en place, après quoi les panneat; sont assemblés entre eux, par exemple par cerclage et fixés sur le réflecteur auxiliaire.The diode wires which are parallel to each other can be separated by a distance of the order of half the wavelength of the radiation emitted, while the spacing between a diode wire and its supply wire would be of the order of tenth of the wavelength. The panels can be made by molding directly giving the desired curved farm with the parallel grooves. The son-diodes are then put in place, after which the panneat; are assembled together, for example by strapping and fixed to the auxiliary reflector.

L'antenne Cassegrain qui vient d'être décrite peut être utilisée notamment dans les systèmes radar de poursuite et d'écartométrie, de trajectographie, d'écoute spatiale, etc.The Cassegrain antenna which has just been described can be used in particular in tracking and ecartometry radar systems, trajectography, spatial listening, etc.

Claims (3)

1. Antenne radar de type à double réflecteur, comportant un réflecteur principal (1) généralement parabolique et un réflecteur auxiliaire (2) généralement hyperbolique, caractérisée par le fait qu'elle comporte, placés devant la surface du réflecteur auxiliaire hyperbolique (2) des panneaux diélectriques (7) ayant une surface sensiblement égale à celle du réflecteur auxiliaire (2) et un galbe sensiblement identique à celui de ce dernier, ces panneaux servant de support à des fils diodes (26, 27) épousant la forme hyperbolique des panneaux, un circuit d'alimentation (12) commandé étant placé derrière le réflecteur auxiliaire (2) et étant relié aux fils diodes des différents panneaux (21, 23) pour alimenter les fils diodes selon l'un de deux états possibles qui sont respectivement un état où les diodes sont bloquées et un état où elles sont polarisées en direct donc passantes.1. Radar antenna of the double reflector type, comprising a main reflector (1) generally parabolic and an auxiliary reflector (2) generally hyperbolic, characterized in that it comprises, placed in front of the surface of the hyperbolic auxiliary reflector (2) dielectric panels (7) having a surface substantially equal to that of the auxiliary reflector (2) and a curve substantially identical to that of the latter, these panels serving to support diode wires (26, 27) matching the hyperbolic form of the panels, a controlled supply circuit (12) being placed behind the auxiliary reflector (2) and being connected to the diode wires of the various panels (21, 23) to supply the diode wires in one of two possible states which are respectively a state where the diodes are blocked and a state where they are polarized in direct therefore passing. 2. Antenne radar suivant la revendication 1, caractérisée en ce que les panneaux sont regroupés en au moins trois ensembles (8, 9, 10), chacun comportant un premier panneau (21) de fils diodes noyés dans un diélectrique et s'étendant parallèles à une direction donnée, un second panneau (23) de fils diodes noyés dans un diélectrique et de direction perpendiculaire à la direction précédente et un troisième panneau (22) situé entre les deux précédents et servant au réglage de l'adaptation des réseaux de fils diodes entre eux, ces trois panneaux étant séparés par des entretoises (24) définissant leur espacement, d'autres entretoises séparant les ensembles (8, 9, 10).2. Radar antenna according to claim 1, characterized in that the panels are grouped into at least three sets (8, 9, 10), each comprising a first panel (21) of diode wires embedded in a dielectric and extending parallel at a given direction, a second panel (23) of diode wires embedded in a dielectric and of direction perpendicular to the previous direction and a third panel (22) located between the two preceding ones and used for adjusting the adaptation of the networks of wires diodes between them, these three panels being separated by spacers (24) defining their spacing, other spacers separating the assemblies (8, 9, 10). 3. Antenne radar suivant la revendication 2, caractérisée en ce que chaque panneau galbé (21, 23) constitué d'un matériau diélectrique est pourvu de rainures parallèles (25) servant de logement aux fils diodes comprenant des diodes (26) reliées par des tronçons de fils.3. Radar antenna according to claim 2, characterized in that each curved panel (21, 23) made of a dielectric material is provided with parallel grooves (25) serving as housing for the diode wires comprising diodes (26) connected by sections of wire.
EP19830400424 1982-03-02 1983-03-02 Dual-reflector antenna with incorporated polarizer Expired EP0088681B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8203422A FR2522888A1 (en) 1982-03-02 1982-03-02 ANTENNA WITH DOUBLE REFLECTOR WITH POLARIZATION TRANSFORMER INCORPORATED
FR8203422 1982-03-02

Publications (2)

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EP0088681A1 true EP0088681A1 (en) 1983-09-14
EP0088681B1 EP0088681B1 (en) 1988-03-02

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EP19830400424 Expired EP0088681B1 (en) 1982-03-02 1983-03-02 Dual-reflector antenna with incorporated polarizer

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EP (1) EP0088681B1 (en)
DE (1) DE3375866D1 (en)
FR (1) FR2522888A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0381037A1 (en) * 1989-01-31 1990-08-08 Siemens-Albis Aktiengesellschaft Antenna system
WO2008125875A2 (en) 2007-04-13 2008-10-23 Basic Device Limited Radiators

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3235870A (en) * 1961-03-09 1966-02-15 Hazeltine Research Inc Double-reflector antenna with polarization-changing subreflector
FR2098372A1 (en) * 1970-07-13 1972-03-10 British Aircraft Corp Ltd
FR2231127A1 (en) * 1973-05-23 1974-12-20 Harris Corp
US3896440A (en) * 1971-11-26 1975-07-22 Westinghouse Electric Corp Retrodirective passive beacon for simulating a moving target
FR2382109A1 (en) * 1977-02-25 1978-09-22 Thomson Csf HYPERFREQUENCY POLARIZATION TRANSFORMER

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3235870A (en) * 1961-03-09 1966-02-15 Hazeltine Research Inc Double-reflector antenna with polarization-changing subreflector
FR2098372A1 (en) * 1970-07-13 1972-03-10 British Aircraft Corp Ltd
US3896440A (en) * 1971-11-26 1975-07-22 Westinghouse Electric Corp Retrodirective passive beacon for simulating a moving target
FR2231127A1 (en) * 1973-05-23 1974-12-20 Harris Corp
FR2382109A1 (en) * 1977-02-25 1978-09-22 Thomson Csf HYPERFREQUENCY POLARIZATION TRANSFORMER

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0381037A1 (en) * 1989-01-31 1990-08-08 Siemens-Albis Aktiengesellschaft Antenna system
WO2008125875A2 (en) 2007-04-13 2008-10-23 Basic Device Limited Radiators

Also Published As

Publication number Publication date
EP0088681B1 (en) 1988-03-02
DE3375866D1 (en) 1988-04-07
FR2522888B1 (en) 1984-04-20
FR2522888A1 (en) 1983-09-09

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