FR2659797A1 - Antenna including a reflector illuminated by a retro-feed device - Google Patents
Antenna including a reflector illuminated by a retro-feed device Download PDFInfo
- Publication number
- FR2659797A1 FR2659797A1 FR9003405A FR9003405A FR2659797A1 FR 2659797 A1 FR2659797 A1 FR 2659797A1 FR 9003405 A FR9003405 A FR 9003405A FR 9003405 A FR9003405 A FR 9003405A FR 2659797 A1 FR2659797 A1 FR 2659797A1
- Authority
- FR
- France
- Prior art keywords
- reflector
- mouth
- secondary reflector
- illumination
- point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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
- H01Q19/12—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 wherein the surfaces are concave
- H01Q19/13—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 wherein the surfaces are concave the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination
- H01Q19/134—Rear-feeds; Splash plate feeds
-
- 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
Abstract
Description
"Antenne comportant un réflecteur illuminé par un dispositif de rétro-alimentation."Antenna comprising a reflector illuminated by a feedback device.
Description
La présente invention concerne une antenne formée d'un réflecteur principal illuminé à partir d'un point d'illumination par un dispositif de rétro-alimentation constitué d'un guide d'onde qui est prévu pour transmettre une onde polarisée et dont l'embouchure se situe au voisinage du point d'illumination et d'un réflecteur secondaire inséré dans le trajet des ondes embouchure-réflecteur principal.Description
The present invention relates to an antenna formed by a main reflector illuminated from an illumination point by a feedback device consisting of a waveguide which is designed to transmit a polarized wave and whose mouthpiece is located in the vicinity of the point of illumination and of a secondary reflector inserted in the path of the mouth-reflector waves.
Ce genre d'antenne est bien connu, on pourra consulter à ce sujet l'ouvrage "Les Antennes" de Léo THOUREL paru aux éditions DUNOD (PARIS) en 1956 et plus particulièrement les pages 306 à 309. This type of antenna is well known, we can consult on this subject the work "Les Antennes" by Léo THOUREL published by DUNOD (PARIS) in 1956 and more particularly pages 306 to 309.
Ce type d'antenne permet une fabrication simple et robuste et trouve des applications importantes, notamment dans le domaine des faisceaux hertziens. Cependant dans ce domaine on utilise une même onde porteuse pour transmettre des informations différentes. Ces informations sont séparées en utilisant la polarisation des ondes de transmission. Ainsi il importe que, lorsque les deux antennes sont placées côte à côte et adaptées à deux polarisations différentes, chacune recoive bien la polarisation qui lui est destinée. This type of antenna allows simple and robust manufacturing and finds important applications, in particular in the field of radio-relay systems. However, in this field, the same carrier wave is used to transmit different information. This information is separated using the polarization of the transmission waves. So it is important that, when the two antennas are placed side by side and adapted to two different polarizations, each one receives the polarization which is intended for it.
En d'autres termes elles doivent présenter un bon rapport de taux de cross-polarisation. Or pour des raisons d'économie de fabrication, on est amené à utiliser des guides d'onde de section circulaire bien meilleur marché que le guide rectangulaire. Cependant l'utilisation d'un guide d'onde circulaire détériore le taux de cross-polarisation. In other words, they must have a good cross-polarization rate ratio. However, for reasons of economy of manufacture, it is necessary to use waveguides of circular section much cheaper than the rectangular guide. However, the use of a circular waveguide deteriorates the cross-polarization rate.
L'invention propose une antenne du genre cité dans le préambule présentant un bon taux de cross-polarisation tout en permettant l'utilisation de guide d'onde circulaire. The invention provides an antenna of the kind mentioned in the preamble having a good cross-polarization rate while allowing the use of circular waveguide.
La description suivante accompagnée des dessins ciannexés, le tout donné à titre d'exemple non limitatif fera bien comprendre comment l'invention peut être réalisée. The following description accompanied by the attached drawings, all given by way of nonlimiting example will make it clear how the invention can be implemented.
La figure 1 montre en perspective une antenne conforme à l'invention. Figure 1 shows in perspective an antenna according to the invention.
La figure 2 montre en perspective le dispositif de rétro-alimentation. Figure 2 shows in perspective the feedback device.
La figure 3 montre l'allure des lignes de champs E à l'intérieur d'un guide d'onde circulaire. FIG. 3 shows the shape of the field lines E inside a circular waveguide.
La figure 4 montre le diagramme de rayonnement selon des composantes EH et EV du champ E. Figure 4 shows the radiation diagram according to EH and EV components of the E field.
La figure 5 montre un réflecteur secondaire en forme de grille. Figure 5 shows a grid-shaped secondary reflector.
La figure 6 montre un réflecteur secondaire en forme de grilles déposées sur un substrat diélectrique. FIG. 6 shows a secondary reflector in the form of grids deposited on a dielectric substrate.
A la figure 1, la référence 1 indique un réflecteur présentant par exemple une forme parabolique de section circulaire de diamètre D. A son sommet 2 un guide d'onde circulaire 3 de diamètre dd traverse le réflecteur et débouche au voisinage du foyer de la parabole qui est le point d'illumination. In FIG. 1, the reference 1 indicates a reflector having for example a parabolic shape of circular section of diameter D. At its apex 2 a circular waveguide 3 of diameter dd passes through the reflector and opens out in the vicinity of the focal point of the parabola which is the point of illumination.
Un réflecteur secondaire 5 de forme circulaire de diamètre d permet de diriger l'onde issue du guide 5 vers le réflecteur 1 et réciproquement.A secondary reflector 5 of circular shape of diameter d makes it possible to direct the wave coming from the guide 5 towards the reflector 1 and vice versa.
La figure 2 montre la disposition relative du réflecteur secondaire 5 et de l'embouchure 8 du guide 3, la plaque 5 est maintenue à une distance "h" de l'embouchure du guide 3 au moyen d'entretoises 11at 11b et 11c fabriquées de préférence en matériau diélectrique. Figure 2 shows the relative arrangement of the secondary reflector 5 and the mouth 8 of the guide 3, the plate 5 is kept at a distance "h" from the mouth of the guide 3 by means of spacers 11at 11b and 11c made of preferably in dielectric material.
La figure 3 montre l'allure de lignes de champ E transmis par un guide d'onde circulaire transmettant l'onde selon le mode fondamental, c'est-à-dire TE1,1. Si la ligne de champ LC du champ E passant par le centre C du guide d'onde est parfaitement rectiligne avec une direction , par contre les lignes de champ s'incurvent lorsque on les considère près du périmètre. Ainsi en un point P loin du centre C la ligne de champ LP présente deux composantes : la première, EV,
4 parallèle à V et une autre EH parallèle à H perpendiculaire
4 à V ; c'est cette deuxième composante qui dégrade le taux de cross-polarisation selon l'angle d'observation en site (8).FIG. 3 shows the appearance of field lines E transmitted by a circular waveguide transmitting the wave according to the fundamental mode, that is to say TE1,1. If the field line LC of field E passing through the center C of the waveguide is perfectly rectilinear with a direction, on the other hand the field lines curl when considered near the perimeter. Thus at a point P far from the center C the field line LP has two components: the first, EV,
4 parallel to V and another EH parallel to H perpendicular
4 to V; it is this second component which degrades the cross-polarization rate according to the angle of observation in elevation (8).
La figure 4 montre l'allure du diagramme de rayonnement d'une antenne du type de la figure 1. En trait plein, on a représenté le diagramme 20, selon le champ EPV et en pointillé le diagramme 21 selon le champ EPH d'antennes de l'art antérieur. EPV est la valeur N du champ E vertical rayonné par l'antenne de l'invention et EPH la valeur du champ horizontal selon la direction 8. Le taux de cross polarisation r est alors EPV ~
T = EPH = 18 dB. FIG. 4 shows the appearance of the radiation diagram of an antenna of the type of FIG. 1. In solid line, diagram 20 has been represented, according to the EPV field and dotted diagram 21 according to the EPH field of antennas of the prior art. EPV is the value N of the vertical field E radiated by the antenna of the invention and EPH the value of the horizontal field along the direction 8. The rate of cross polarization r is then EPV ~
T = EPH = 18 dB.
Conformément à l'invention, le rapport de cross-polarisation est amélioré par le fait que la plaque formant réflecteur secondaire est constitué par un filtre dichroïque. According to the invention, the cross-polarization ratio is improved by the fact that the secondary reflector plate is constituted by a dichroic filter.
Ce filtre dichroïque peut se présenter sous la forme d'une grille métallique telle que représenté à la figure 5 ou d'une façon plus avantageuse par une plaque de circuit imprimé présentant aussi ce motif de grille montré partiellement à la figure 6 pour des raisons de clarté. Mais il va de soi que ce motif retourne tout le réflecteur secondaire. Cette plaque est déposée sur un substrat diélectrique 20. This dichroic filter can be in the form of a metal grid as shown in Figure 5 or more advantageously by a printed circuit board also having this grid pattern partially shown in Figure 6 for reasons of clarity. But it goes without saying that this pattern returns the entire secondary reflector. This plate is deposited on a dielectric substrate 20.
A titre d'exemple, une antenne fonctionnant dans la gamme des 23 GHz présente un diamètre D du réflecteur principal : D = 38 cm. For example, an antenna operating in the 23 GHz range has a diameter D of the main reflector: D = 38 cm.
Le réflecteur secondaire a un diamètre :d = 5 cm, ce dernier est situé à une distance h de 15 mm devant l'embouchure du guide pénétrant de 10 cm dans le réflecteur principal. La grille présente des parties métalliques ayant une épaisseur e = 0,5 mm espacées d'une distance v = 1 mm. On a obtenu ainsi une amélioration du taux de cross-polarisation, tel que représenté à la figure 4 par des traits en petites croix, c'est-à-dire le taux de cross-polarisation est toujours supérieur à 30 dB. Le diamètre dd du guide d'onde est de l'ordre de 1 cm. The secondary reflector has a diameter: d = 5 cm, the latter is located at a distance h of 15 mm in front of the mouth of the guide penetrating 10 cm into the main reflector. The grid has metal parts having a thickness e = 0.5 mm spaced by a distance v = 1 mm. There was thus obtained an improvement in the cross-polarization rate, as represented in FIG. 4 by lines in small crosses, that is to say the cross-polarization rate is always greater than 30 dB. The diameter dd of the waveguide is of the order of 1 cm.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9003405A FR2659797A1 (en) | 1990-03-16 | 1990-03-16 | Antenna including a reflector illuminated by a retro-feed device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9003405A FR2659797A1 (en) | 1990-03-16 | 1990-03-16 | Antenna including a reflector illuminated by a retro-feed device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR2659797A1 true FR2659797A1 (en) | 1991-09-20 |
Family
ID=9394830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR9003405A Withdrawn FR2659797A1 (en) | 1990-03-16 | 1990-03-16 | Antenna including a reflector illuminated by a retro-feed device |
Country Status (1)
| Country | Link |
|---|---|
| FR (1) | FR2659797A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2715796A1 (en) * | 1977-04-07 | 1978-10-12 | Siemens Ag | Cassegrain antenna with main reflector - has second reflector formed as metallised layer on bottom of bottle shaped plastics hood mounted at open end |
| JPS59194511A (en) * | 1983-04-19 | 1984-11-05 | Mitsubishi Electric Corp | Parabolic antenna for circular polarized wave |
| FR2580868A1 (en) * | 1985-04-19 | 1986-10-24 | Thomson Csf | DEVICE REFLECTING THE ELECTROMAGNETIC WAVES OF A POLARIZATION AND METHOD FOR PRODUCING THE SAME |
-
1990
- 1990-03-16 FR FR9003405A patent/FR2659797A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2715796A1 (en) * | 1977-04-07 | 1978-10-12 | Siemens Ag | Cassegrain antenna with main reflector - has second reflector formed as metallised layer on bottom of bottle shaped plastics hood mounted at open end |
| JPS59194511A (en) * | 1983-04-19 | 1984-11-05 | Mitsubishi Electric Corp | Parabolic antenna for circular polarized wave |
| FR2580868A1 (en) * | 1985-04-19 | 1986-10-24 | Thomson Csf | DEVICE REFLECTING THE ELECTROMAGNETIC WAVES OF A POLARIZATION AND METHOD FOR PRODUCING THE SAME |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 9, no. 53 (E-301)(1776) 07 mars 1985, & JP-A-59 194511 (MITSUBISHI) 05 novembre 1984, * |
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| ST | Notification of lapse |