EP0088681B1 - Dual-reflector antenna with incorporated polarizer - Google Patents

Dual-reflector antenna with incorporated polarizer Download PDF

Info

Publication number
EP0088681B1
EP0088681B1 EP19830400424 EP83400424A EP0088681B1 EP 0088681 B1 EP0088681 B1 EP 0088681B1 EP 19830400424 EP19830400424 EP 19830400424 EP 83400424 A EP83400424 A EP 83400424A EP 0088681 B1 EP0088681 B1 EP 0088681B1
Authority
EP
European Patent Office
Prior art keywords
panels
diodes
reflector
diode
panel
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
EP19830400424
Other languages
German (de)
French (fr)
Other versions
EP0088681A1 (en
Inventor
Albert Dupressoir
François Salvat
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.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0088681A1 publication Critical patent/EP0088681A1/en
Application granted granted Critical
Publication of EP0088681B1 publication Critical patent/EP0088681B1/en
Expired legal-status Critical Current

Links

Images

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
    • 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, ultimately, 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 source opening, this polarizer being with blades or 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 space requirement 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.
  • a double reflection antenna intended to transmit or receive circularly polarized radiation.
  • This antenna comprises a main reflector, a horn, a secondary reflector which reflects the circularly polarized radiation in one direction and which emits circularly polarized radiation in the other direction.
  • the secondary reflector therefore comprises two quarter-wave plates spaced apart by a dielectric containing an array of conductors. Such a secondary reflector does not make it possible to modify the polarization of the transmitted wave, that is to say to effect a polarization switching.
  • 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 a direct polarization of the diodes or an absence of polarization or a reverse polarization such that the diodes are blocked.
  • the switchable polarizer according to the invention works on reflection and not on transmission: it is crossed once by an incident wave from the source, which is thus subjected to polarization partial, and another time after reflection of this partially polarized wave on the reflector auxiliary.
  • 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 son separated by diodes all oriented in the same direction and the sections have a length of the order of a fraction of wavelength.
  • 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 wire-diodes and the wire-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 (hyperboloid 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 with the main reflector by four rigid rods 4 of small diameter arranged in planes at 45 ° of 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 wires- parallel diodes oriented generally 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.
  • FIG. 2 shows the detail of embodiment of the electronically controlled polarizer placed in front of the auxiliary reflector 2.
  • hyperbolic 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 made 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 produced by molding directly giving the desired curved shape with the parallel grooves. The son-diodes are then put in place, after which the panels are assembled together, for example by strapping and fixed on 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.

Landscapes

  • Aerials With Secondary Devices (AREA)

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 radioélectrique 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, ultimately, 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.Indeed, a solution usually used consisted in providing a polarizer in front of the source opening, this polarizer being with blades or 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 space requirement 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 owing to the fact that 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, the opening of which 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.

Il est également connu du document FR-A-2 098 372, une antenne à double réflexion destinée à émettre ou à recevoir un rayonnement polarisé circulairement. Cette antenne comporte un réflecteur principal, un cornet, un réflecteur secondaire qui réfléchit le rayonnement polarisé circulairement dans un sens et qui émet un rayonnement polarisé circulairement dans l'autre sens. Le réflecteur secondaire comprend pour cela deux plaques quart d'onde espacées par un diélectrique contenant un réseau de conducteurs. Un tel réflecteur secondaire ne permet pas de modifier la polarisation de l'onde émise c'est-à-dire d'effectuer une commutation de polarisation.It is also known from document FR-A-2 098 372, a double reflection antenna intended to transmit or receive circularly polarized radiation. This antenna comprises a main reflector, a horn, a secondary reflector which reflects the circularly polarized radiation in one direction and which emits circularly polarized radiation in the other direction. The secondary reflector therefore comprises two quarter-wave plates spaced apart by a dielectric containing an array of conductors. Such a secondary reflector does not make it possible to modify the polarization of the transmitted wave, that is to say to effect a polarization switching.

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 a direct polarization of the diodes or 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 works on reflection and not on transmission: it is crossed once by an incident wave from the source, which is thus subjected to polarization partial, and another time after reflection of this partially polarized wave on the reflector auxiliary.

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 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,
  • - Figure 3 shows a detail of embodiment of a son-diode panel.

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 son separated by diodes all oriented in the same direction and the sections have a length of the order of a fraction of wavelength.

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 wire-diodes and the wire-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 (paraboloïde de révolution) et un réflecteur auxiliaire convexe 2 de forme généralement hyperbolique (hyperboloïde 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 (hyperboloid 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 with the main reflector by four rigid rods 4 of small diameter arranged in planes at 45 ° of 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 réflecteur 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-diodes 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 wires- parallel diodes oriented generally 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-diodes sera donné plus loin.The details of the sets of wire-diode networks will be given below.

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 montre le détail de réalisation du polariseur à commande électronique placé devant le réflecteur auxiliaire 2.FIG. 2 shows the detail of embodiment 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 sont 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 wire-diode networks are protected by a thin radome 20 and each preferably consists of three panels which are respectively:
  • a panel 21 of wire-diodes embedded in a dielectric,
  • a dielectric panel 22 used to adjust the adaptation of the wire-diode networks to one another,
  • a panel 23 of diode wires which can be oriented differently from those of panel 21.

Ces trois panneaux 21, 22, 23 sont séparés par des entretoises qui définissent leur espacement et ils ont tous la même forme sensiblementThese three panels 21, 22, 23 are separated by spacers which define their spacing and they all have the same shape substantially

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.hyperbolic 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 made 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 forme galbée désirée avec les rainures parallèles. Les fils-diodes sont alors mis en place, après quoi les panneaux 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 produced by molding directly giving the desired curved shape with the parallel grooves. The son-diodes are then put in place, after which the panels are assembled together, for example by strapping and fixed on 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. 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), a 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.
2. Radar antenna according to claim 1, characterized in that the panels are grouped in at least three sets (8, 9, 10) each comprising a first panel (21) of diode wires embedded in a dielectric and extending in parallel to a given direction, a second panel (23) of diode wires embedded in a dielectric and having a direction perpendicular to the preceding direction, and a third panel (22) located between the two preceding panels and used to adjust the adaptation of the diode wire networks between each other, these three panels being separated by struts (24) defining their spacing, further struts separating the sets (8, 9, 10).
3. Radar antenna according to claim 2, characterized in that each arched panel (21, 23) formed of a dielectric material is provided with parallel grooves (25) for accommodation of the diode wires comprising diodes (26) connected by wire sections.
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)

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

Family

ID=9271489

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830400424 Expired EP0088681B1 (en) 1982-03-02 1983-03-02 Dual-reflector antenna with incorporated polarizer

Country Status (3)

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

Families Citing this family (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
GB0707147D0 (en) 2007-04-13 2007-05-23 Basic Device Ltd Radiators

Family Cites Families (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
GB1305117A (en) * 1970-07-13 1973-01-31
US3896440A (en) * 1971-11-26 1975-07-22 Westinghouse Electric Corp Retrodirective passive beacon for simulating a moving target
DK143827C (en) * 1973-05-23 1982-03-08 Harris Corp PASSIVE ANTENNA ELEMENT
FR2382109A1 (en) * 1977-02-25 1978-09-22 Thomson Csf HYPERFREQUENCY POLARIZATION TRANSFORMER

Also Published As

Publication number Publication date
DE3375866D1 (en) 1988-04-07
EP0088681A1 (en) 1983-09-14
FR2522888B1 (en) 1984-04-20
FR2522888A1 (en) 1983-09-09

Similar Documents

Publication Publication Date Title
EP0403910B1 (en) Radiating, diplexing element
EP0205212B1 (en) Modular microwave antenna units and antenna composed of such units
EP1416586B1 (en) Antenna with an assembly of filtering material
EP1407512B1 (en) Antenna
EP0667984B1 (en) Monopolar wire-plate antenna
EP0457880B1 (en) Airborne iff antenna with switchable multiple diagrams
EP1568104B1 (en) Multiple-beam antenna with photonic bandgap material
EP0886889A1 (en) Wide band printed network antenna
EP0899814A1 (en) Radiating structure
FR2907602A1 (en) MULTIPLE WIRE ANTENNA WITH DOUBLE POLARIZATION.
WO2014202498A1 (en) Source for parabolic antenna
CA2460820C (en) Broadband or multiband antenna
EP1554777B1 (en) Multibeam antenna with photonic bandgap material
EP1551078A1 (en) Omnidirectional antenna with steerable diagram
EP0088681B1 (en) Dual-reflector antenna with incorporated polarizer
EP3175509B1 (en) Log-periodic antenna with wide frequency band
FR2518828A1 (en) Frequency spatial filter for two frequency microwave antenna - comprising double sandwich of metallic grids and dielectric sheets
CA2808511C (en) Flat antenna for a terminal operating in dual circular polarisation, airborne terminal and satellite telecommunication system featuring at least one antenna
FR2552273A1 (en) Omnidirectional microwave antenna
FR2854737A1 (en) Earth communications geostationary satellite multiple beam antenna having focal point radiation pattern and photonic band gap material outer surface with periodicity default providing narrow pass band
WO1991018428A1 (en) Planar orientable antenna operating in the microwave band
WO2007074307A1 (en) Configurable bipolarization reflector
FR3076088A1 (en) QUASI-OPTICAL BEAM FORMER, ELEMENTARY ANTENNA, ANTENNA SYSTEM, PLATFORM AND METHOD OF TELECOMMUNICATIONS THEREFOR
EP3155690A1 (en) Flat antenna for satellite communication
FR2981514A1 (en) Reconfigurable antenna system for e.g. ultra broadband application, has controller controlling connectors to pass from spiral antenna configuration to another configuration in which conductive elements form square spiral antenna array

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE GB IT NL

17P Request for examination filed

Effective date: 19831224

17Q First examination report despatched

Effective date: 19860204

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB IT NL

ITF It: translation for a ep patent filed
REF Corresponds to:

Ref document number: 3375866

Country of ref document: DE

Date of ref document: 19880407

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19900331

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19911001

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20010214

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20010222

Year of fee payment: 19

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020302

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20021001

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20020302