EP2416449A1 - Parabolic-reflector antenna - Google Patents
Parabolic-reflector antenna Download PDFInfo
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- EP2416449A1 EP2416449A1 EP11176114A EP11176114A EP2416449A1 EP 2416449 A1 EP2416449 A1 EP 2416449A1 EP 11176114 A EP11176114 A EP 11176114A EP 11176114 A EP11176114 A EP 11176114A EP 2416449 A1 EP2416449 A1 EP 2416449A1
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- Prior art keywords
- antenna
- reflector
- groove
- antenna according
- traps
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/14—Reflecting surfaces; Equivalent structures
- H01Q15/16—Reflecting surfaces; Equivalent structures curved in two dimensions, e.g. paraboloidal
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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
- H01Q19/02—Details
- H01Q19/021—Means for reducing undesirable effects
- H01Q19/022—Means for reducing undesirable effects for reducing the edge scattering of reflectors
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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
- H01Q19/02—Details
- H01Q19/021—Means for reducing undesirable effects
- H01Q19/026—Means for reducing undesirable effects for reducing the primary feed spill-over
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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
- H01Q19/12—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
Definitions
- the present invention relates to a parabolic reflector telecommunication antenna, used in particular for mobile communication networks. These antennas operate indifferently in transmitter mode or in receiver mode, corresponding to two opposite directions of RF wave propagation. It should be noted that all the reasonings apply to the antennas as well in reception as in emission.
- the invention relates to a microwave antenna with a parabolic reflector. The invention applies both to dual reflector antennas and antennas having only one reflector.
- a conventional radiating aperture antenna comprises a reflector having a concavity, for example having the form of a paraboloid of revolution about the axis of symmetry of the antenna, and a feeding device located along the axis of the antenna. symmetry of the antenna transmitting the electromagnetic waves emitted or received by the antenna.
- the end of the radiofrequency waveguide is at the focus of the reflector.
- the waveguide is inserted into an orifice on the axis of the reflector, and its end is bent 180 ° to face the reflector.
- the maximum half-angle of radiation at the folded end of the waveguide to illuminate the reflector is small, of the order of 70 °.
- the distance between the reflector and the end of the waveguide must therefore be large enough to illuminate the entire surface of the reflector.
- the value of the diameter D is determined by the central working frequency of the antenna.
- the F / D ratio is of the order of 0.36.
- F is the focal length of the reflector (distance between the top of the reflector and its focus)
- D is the diameter of the reflector.
- a parabolic antenna with a low F / D value of less than or equal to 0.25, for example around 0.17 (“deep dish” in English), has a more absorbent skirt. short than the shallow reflector antenna. Nevertheless, the field on the edge of the antenna is higher in the case of a deep dish antenna. Due to the very short height of the skirt, the field level on the edge of the antenna is close to the field level at the end of the parabolic reflector (about 2 dB at 3 dB gap). In the case of a shallow reflector antenna, the difference is higher and about 10 dB. Distribution currents may appear on the edge of the antenna and disturb the forward / backward ratio of the radiation pattern by the appearance of wave diffraction on the peripheral edge of the antenna. The values of the radiation pattern exceed the maximum values allowed by the ETSI class 3 mask.
- the object of the present invention is to propose a parabolic reflector microwave antenna in which the diffraction of the waves appearing on the outer peripheral edge of the antenna has been substantially reduced.
- the invention also aims to provide a parabolic reflector antenna whose front / rear ratio is improved.
- the invention also aims to provide a parabolic reflector antenna requiring a skirt of lesser height.
- the object of the present invention is an antenna comprising a parabolic reflector, provided with a skirt, cooperating with a means for emitting incident radiation in the direction of the reflector.
- the antenna comprises means for reducing the distribution current appearing on the edge of the antenna, these means being composed of traps having the shape of at least one groove, the side walls of which are arranged perpendicularly to the frontal or lateral external surface. the peripheral edge of the antenna.
- the traps are even in number and arranged symmetrically.
- the angle formed by the sector of a trap is preferably of the order of 60 °. More preferably each trap has a shape adapted to the rounding of the peripheral edge of the antenna.
- each trap has the shape of at least one conductive surface groove.
- the groove is formed of a material which may be a metal or a metallized plastic.
- the groove has dimensions of the order of a fraction of the wavelength of the incident radiation.
- the groove has a depth of the same order of magnitude as its width, and more preferably the width and depth are equal.
- the groove may have a section selected from a flat-bottom U-shaped section, a U-shaped section with a rounded bottom, and a V-shaped section. Its side walls may be straight or inclined.
- the present invention reduces the height of the skirt attached to the parabolic reflector, which provides a cost advantage and significant size.
- the invention can be used in applications such as, for example, the production of terrestrial antennas for receiving a radiofrequency signal emitted by a satellite or the link between two terrestrial antennas, and more generally in any application concerning radiofrequency links.
- point-to-point in the frequency band from 7 GHz to 40 GHz.
- the figure 1 is a diagram showing a reflector 1 , having the shape of a parabola arc, disposed facing a waveguide 2 which emits incident radiation 3 towards the reflector 1 .
- Most of the incident radiation 3 is reflected on the reflector 1 and forms the radiation emitted 4 by the antenna. However, part of the incident radiation 3 is returned in a divergent direction, and causes overflow losses 5 .
- another part of the incident radiation 3 reaches the edges of the reflector 1, where a diffraction 6 occurs, which increases the field at the rear of the parabolic reflector 1 and contributes to deteriorating the forward / backward ratio.
- An antenna shown in section on the figure 2 , usually comprises a parabolic reflector 1 provided with a skirt 7, forming a cylindrical wall, internally lined with an absorbent material 8 and closed by a radome 9 .
- the incident radiation 3 coming from the waveguide 2 is reflected by the reflector 1 in the form of a radiation emitted 4 .
- the radiation 10 which projects beyond the reflector 1 is absorbed by the absorbent material 8 of the skirt 7 .
- the characteristic of the radiation pattern of a circular horn waveguide antenna is determined by the mode of transmission of the horn waveguide, which is generally the dominant mode or mode TE 11 . Since the dominant mode TE 11 is asymmetric around the central axis of the horn, the horn antenna radiation pattern is disadvantageously asymmetrical around the central axis. When using a horn-shaped waveguide with a parabolic reflector, the asymmetric radiation characteristic leads to a reduction of the antenna radiation efficiency and a deterioration of the cross-polarization waves.
- the antenna 30 comprises a reflector 31 surmounted by a skirt 32 closed by a radome 33 plane.
- the diameter D of the reflector 31 of the antenna 30 is of the order of 2 ft (0.6096 m), and the operating frequency range is between 7 GHz and 14 GHz.
- One way to reduce the diffraction of the waves appearing on the outer peripheral edge of the antenna is to suppress the current, in particular using quarter-wave traps. These traps have the shape of grooves with dimensions close to a quarter of the wavelength considered.
- the outer surface of the skirt 32 carries, in lateral position, wave traps 34 with a conductive surface, which may be metallic or made of metallized plastic. As shown on the figure 5 these traps 34 are in the form of grooves whose depth P and the spacing E of the walls of the groove depend on the wavelength ⁇ , the incident RF signal 10 emitted by the waveguide 35 . Preferably, the dimensions E and P of the traps 34 are of the order of ⁇ / 5 at 8 GHz, ie here 8 mm. In this case the traps 34 are in the form of two contiguous parallel grooves with vertical sidewalls arranged perpendicular to the lateral external surface of the skirt 32 . For low frequency operation; it is preferable to use at least two traps 34 .
- the traps are placed in symmetrical position: they are therefore in even numbers. These traps 34 can be placed on only part of the peripheral rim of the antenna, for example diametrically opposed as shown in FIG. figure 3 , or on the entire circumference of the antenna. When the traps do not cover the entire circumference of the antenna, the angle ⁇ formed by the sector of a trap is of the order of 60 °. For example, for an antenna having a diameter of about 65 cm, this represents a length of about 35 cm for each trap.
- the shape of the trap must therefore adapt to the roundness of the peripheral edge of the antenna as shown in FIG. figure 3 .
- the purpose of the traps 34 is to reduce or even eliminate the distribution current 36 on the edge of the antenna 30 in order to reduce the diffraction.
- the principle of their operation is based on the fact that they produce a phase shift of a part of the wave which is then placed in phase opposition with the main wave and is canceled out.
- the antenna 40 comprises a reflector 41 surmounted by a skirt 42 closed by a radome 43 .
- the inner surface of the skirt 42 is coated with an absorbent material 44 .
- the outer surface of the skirt 42 carries, in the frontal position, wave traps 45 .
- the traps 45 are in the form of a single groove with vertical lateral walls arranged perpendicularly to the front external surface of the skirt 42 .
- the angle ⁇ formed by the sector of a trap is of the order of 60 °, when the traps do not cover the entire circumference of the antenna. For example, for an antenna having a diameter of about 65 cm, this represents a length of about 35 cm for each trap.
- the shape of the trap adopts the rounding of the edge of the antenna.
- the traps 45 can be fixed on the edge forming the circumference of the radome 43 .
- traps can be placed both in lateral position and in frontal position on the antenna. The number of traps is not limited.
- the section of the groove may have a varied shape, for example a U-shaped section with a flat bottom as shown in the drawings.
- Figures 4 to 6 a U-shaped section with a rounded bottom 50 as on the figure 7a or a V-shaped section 51 like on the figure 7b .
- the side walls flanking the groove can be straight as shown on the Figures 4 to 6 , or inclined 52 as on the Figure 7c .
- the side lobes 61 exceeds the ETSI standard.
- the side lobes 62 of an antenna provided with traps according to one embodiment of the invention are very clearly reduced. This shows that the traps are an effective means of reducing the diffraction of the waves appearing on the outer peripheral edge of an antenna.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
Description
La présente invention se rapporte à une antenne de télécommunication à réflecteur parabolique, utilisée notamment pour les réseaux de communication mobile. Ces antennes fonctionnent indifféremment en mode transmetteur ou en mode récepteur, correspondant à deux sens opposés de propagation des ondes RF. II faut noter que tous les raisonnements s'appliquent aux antennes aussi bien en réception qu'en émission. L'invention concerne en particulier une antenne de type microonde à réflecteur parabolique. L'invention s'applique aussi bien aux antennes à double réflecteur qu'aux antennes n'ayant qu'un réflecteur.The present invention relates to a parabolic reflector telecommunication antenna, used in particular for mobile communication networks. These antennas operate indifferently in transmitter mode or in receiver mode, corresponding to two opposite directions of RF wave propagation. It should be noted that all the reasonings apply to the antennas as well in reception as in emission. In particular, the invention relates to a microwave antenna with a parabolic reflector. The invention applies both to dual reflector antennas and antennas having only one reflector.
Une antenne à ouverture rayonnante conventionnelle comprend un réflecteur présentant une concavité, ayant par exemple la forme d'un paraboloïde de révolution autour de l'axe de symétrie de l'antenne, et un dispositif d'alimentation situé le long de l'axe de symétrie de l'antenne transmettant les ondes électromagnétiques émises ou reçues par l'antenne.A conventional radiating aperture antenna comprises a reflector having a concavity, for example having the form of a paraboloid of revolution about the axis of symmetry of the antenna, and a feeding device located along the axis of the antenna. symmetry of the antenna transmitting the electromagnetic waves emitted or received by the antenna.
L'extrémité du guide d'onde radiofréquence se trouve au foyer du réflecteur. Le guide d'onde est inséré dans un orifice situé sur l'axe du réflecteur, et son extrémité est repliée à 180° afin de faire face au réflecteur. Le demi-angle maximum de rayonnement à l'extrémité repliée du guide d'onde pour éclairer le réflecteur est faible, de l'ordre de 70°. La distance entre le réflecteur et l'extrémité du guide d'onde doit donc être suffisamment importante pour permettre d'éclairer la totalité de la surface du réflecteur. Dans ces antennes à réflecteur parabolique, la valeur du diamètre D est déterminée par la fréquence centrale de travail de l'antenne. Plus la fréquence de travail de l'antenne est basse (par exemple 7,1 GHz ou 10 GHz) et plus le diamètre du réflecteur est important à gain d'antenne équivalent : il faut alors que l'extrémité du guide d'onde soit très éloignée du réflecteur pour bien l'éclairer (mode émission), et l'antenne devient donc d'autant plus encombrante que la fréquence de travail est basse.The end of the radiofrequency waveguide is at the focus of the reflector. The waveguide is inserted into an orifice on the axis of the reflector, and its end is bent 180 ° to face the reflector. The maximum half-angle of radiation at the folded end of the waveguide to illuminate the reflector is small, of the order of 70 °. The distance between the reflector and the end of the waveguide must therefore be large enough to illuminate the entire surface of the reflector. In these parabolic reflector antennas, the value of the diameter D is determined by the central working frequency of the antenna. The lower the working frequency of the antenna (for example 7.1 GHz or 10 GHz) and the greater the diameter of the reflector is important at equivalent antenna gain: it is then necessary that the end of the waveguide is very far from the reflector to illuminate it well (emission mode), and the antenna becomes more cumbersome as the working frequency is low.
Pour les antennes à réflecteur peu profond (« shallow reflector » en anglais), le rapport F/D est de l'ordre de 0,36. Dans ce rapport, F est la distance focale du réflecteur (distance entre le sommet du réflecteur et son foyer) et D est le diamètre du réflecteur. Ces antennes présentent des pertes par débordement (« spillover » en anglais) qui sont élevées et diminuent le rapport avant/arrière (« front-to-back ratio » en anglais) de l'antenne. En outre une diffraction des ondes apparaît à partir sur le bord périphérique de l'antenne et augmente le champ à l'arrière du réflecteur parabolique.For the shallow reflector antennas ("shallow reflector" in English), the F / D ratio is of the order of 0.36. In this report, F is the focal length of the reflector (distance between the top of the reflector and its focus) and D is the diameter of the reflector. These antennas have spillover losses which are high and reduce the front-to-back ratio of the antenna. In addition, wave diffraction appears from the peripheral edge of the antenna and increases the field at the rear of the parabolic reflector.
Les pertes par débordement, exprimées en dB, conduisent à une pollution de l'environnement par les ondes RF et doivent être limitées à des niveaux définis par des normes. Afin de limiter notamment le rayonnement latéral, une solution habituelle est d'attacher à la périphérie du réflecteur primaire une jupe (« shroud » en anglais qui a la forme d'un cylindre, de diamètre voisin de celui du réflecteur primaire et de hauteur convenable, revêtu intérieurement d'une couche absorbant le rayonnement RF. Outre l'encombrement qui en résulte, cette solution connue présente l'inconvénient aujourd'hui gênant du coût du matériau de la jupe, ainsi que du coût d'assemblage de cette jupe sur le réflecteur.Overflow losses, expressed in dB, lead to environmental pollution by RF waves and must be limited to levels defined by standards. In order to limit lateral radiation in particular, a usual solution is to attach to the periphery of the primary reflector a skirt ("shroud" in English which has the shape of a cylinder, of diameter close to that of the primary reflector and of suitable height In addition to the resulting bulk, this known solution has the disadvantage of the cost of the material of the skirt, as well as the cost of assembling this skirt on the inside. the reflector.
Avec des performances similaires du diagramme de rayonnement, une antenne parabolique avec une faible valeur du rapport F/D inférieur ou égal à 0,25, par exemple autour de 0,17 (« deep dish » en anglais), a une jupe absorbante plus courte que l'antenne à réflecteur peu profond. Néanmoins, le champ sur le bord de l'antenne est plus élevé dans le cas d'une antenne parabolique profonde. En raison de la hauteur très courte de la jupe, le niveau du champ sur le bord de l'antenne est proche du niveau du champ à l'extrémité du réflecteur parabolique (environ 2 dB à 3 dB d'écart). Dans le cas d'une antenne à réflecteur peu profond, l'écart est plus élevé et d'environ 10 dB. Des courants de distribution peuvent apparaître sur le bord de l'antenne et perturber le rapport avant/arrière du diagramme de rayonnement par l'apparition de diffraction des ondes sur le bord périphérique de l'antenne. Les valeurs du diagramme de rayonnement excèdent les valeurs maximales autorisées par le gabarit de la classe 3 ETSI.With similar performance of the radiation pattern, a parabolic antenna with a low F / D value of less than or equal to 0.25, for example around 0.17 ("deep dish" in English), has a more absorbent skirt. short than the shallow reflector antenna. Nevertheless, the field on the edge of the antenna is higher in the case of a deep dish antenna. Due to the very short height of the skirt, the field level on the edge of the antenna is close to the field level at the end of the parabolic reflector (about 2 dB at 3 dB gap). In the case of a shallow reflector antenna, the difference is higher and about 10 dB. Distribution currents may appear on the edge of the antenna and disturb the forward / backward ratio of the radiation pattern by the appearance of wave diffraction on the peripheral edge of the antenna. The values of the radiation pattern exceed the maximum values allowed by the
La présente invention a pour but de proposer une antenne microonde à réflecteur parabolique dans laquelle la diffraction des ondes apparaissant sur le bord périphérique extérieur de l'antenne a été sensiblement réduite.The object of the present invention is to propose a parabolic reflector microwave antenna in which the diffraction of the waves appearing on the outer peripheral edge of the antenna has been substantially reduced.
L'invention a aussi pour but de proposer une antenne à réflecteur parabolique dont le rapport avant/arrière est amélioré.The invention also aims to provide a parabolic reflector antenna whose front / rear ratio is improved.
L'invention a encore pour but de proposer une antenne à réflecteur parabolique nécessitant une jupe de hauteur moindre.The invention also aims to provide a parabolic reflector antenna requiring a skirt of lesser height.
L'objet de la présente invention est une antenne comportant un réflecteur parabolique, muni d'une jupe, coopérant avec un moyen d'émission d'un rayonnement incident en direction du réflecteur. L'antenne comprend des moyens pour diminuer le courant de distribution apparaissant sur le bord de l'antenne, ces moyens étant composés de pièges ayant la forme d'au moins une gorge dont les parois latérales sont disposées perpendiculairement à la surface extérieure frontale ou latérale du rebord périphérique de l'antenne.The object of the present invention is an antenna comprising a parabolic reflector, provided with a skirt, cooperating with a means for emitting incident radiation in the direction of the reflector. The antenna comprises means for reducing the distribution current appearing on the edge of the antenna, these means being composed of traps having the shape of at least one groove, the side walls of which are arranged perpendicularly to the frontal or lateral external surface. the peripheral edge of the antenna.
De préférence, les pièges sont en nombre pair et disposés symétriquement.Preferably, the traps are even in number and arranged symmetrically.
Lorsque les pièges ne couvrent pas la totalité de la circonférence de l'antenne, l'angle formé par le secteur d'un piège est de préférence de l'ordre de 60°. De préférence encore chaque piège a une forme adaptée à l'arrondi du bord périphérique de l'antenne.When the traps do not cover the entire circumference of the antenna, the angle formed by the sector of a trap is preferably of the order of 60 °. More preferably each trap has a shape adapted to the rounding of the peripheral edge of the antenna.
Selon un mode de réalisation particulier, chaque piège a la forme d'au moins une gorge à surface conductrice. En particulier la gorge est formée d'un matériau qui peut être un métal ou un plastique métallisé.According to a particular embodiment, each trap has the shape of at least one conductive surface groove. In particular the groove is formed of a material which may be a metal or a metallized plastic.
Selon un mode de réalisation préféré, la gorge a des dimensions de l'ordre d'une fraction de la longueur d'onde du rayonnement incident.According to a preferred embodiment, the groove has dimensions of the order of a fraction of the wavelength of the incident radiation.
De préférence, la gorge a une profondeur du même ordre de grandeur que sa largeur, et de préférence encore la largeur et la profondeur sont égales.Preferably, the groove has a depth of the same order of magnitude as its width, and more preferably the width and depth are equal.
La gorge peut avoir une section choisie parmi une section en forme de U à fond plat, une section en forme de U à fond arrondi et une section en forme de V. Ses parois latérales peuvent être droites ou inclinées.The groove may have a section selected from a flat-bottom U-shaped section, a U-shaped section with a rounded bottom, and a V-shaped section. Its side walls may be straight or inclined.
La présente invention permet de réduire la hauteur de la jupe fixée sur le réflecteur parabolique, ce qui procure un avantage de coût et d'encombrement appréciable.The present invention reduces the height of the skirt attached to the parabolic reflector, which provides a cost advantage and significant size.
L'invention est utilisable dans des applications telles que, par exemple, la réalisation d'antennes terrestres permettant de recevoir un signal radiofréquence émis par un satellite ou la liaison entre deux antennes terrestres, et de façon plus générale dans toute application concernant les liaisons radiofréquence point à point dans la bande de fréquence de 7 GHz à 40 GHz.The invention can be used in applications such as, for example, the production of terrestrial antennas for receiving a radiofrequency signal emitted by a satellite or the link between two terrestrial antennas, and more generally in any application concerning radiofrequency links. point-to-point in the frequency band from 7 GHz to 40 GHz.
D'autres caractéristiques et avantages de la présente invention apparaîtront à la lecture de la description qui suit d'un mode de réalisation, donné bien entendu à titre illustratif et non limitatif, et dans le dessin annexé sur lequel
- la
figure 1 montre schématiquement le trajet du rayonnement reçu par le réflecteur parabolique, - la
figure 2 représente en coupe schématique une antenne à réflecteur parabolique muni d'une jupe haute selon l'art antérieur, - la
figure 3 représente une antenne à réflecteur parabolique munie de pièges selon un mode de réalisation de l'invention, - la
figure 4 est une coupe schématique d'une antenne à réflecteur parabolique selon un mode de réalisation de l'invention, - la
figure 5 est une vue de détail des pièges selon un premier mode de réalisation de l'invention, - la
figure 6 est une vue de détail des pièges selon un deuxième mode de réalisation de l'invention, - les
figures 7a à 7c montrent différente section de gorges, - les
figures 8a et 8b comparent les diagrammes du rayonnement dans le plan horizontal d'une antenne de l'art antérieur et d'une antenne munie d'un piège selon un mode de réalisation de l'invention ; sur lesfigures 6a et 6b , l'intensité du rayonnement J en dB est donné en ordonnée, et en abscisse l'angle d'émission/réception β en degrés.
- the
figure 1 schematically shows the path of the radiation received by the parabolic reflector, - the
figure 2 represents in schematic section a parabolic reflector antenna provided with a high skirt according to the prior art, - the
figure 3 represents a parabolic reflector antenna provided with traps according to one embodiment of the invention, - the
figure 4 is a schematic section of a parabolic reflector antenna according to an embodiment of the invention, - the
figure 5 is a detailed view of the traps according to a first embodiment of the invention, - the
figure 6 is a detailed view of the traps according to a second embodiment of the invention, - the
Figures 7a to 7c show different section of throats, - the
Figures 8a and 8b compare the radiation patterns in the horizontal plane of a prior art antenna and an antenna provided with a trap according to one embodiment of the invention; on theFigures 6a and 6b , the intensity of the radiation J in dB is given in ordinate, and in abscissa the angle of emission / reception β in degrees.
Sur ces figures, les éléments identiques portent les mêmes numéros de référence.In these figures, the identical elements bear the same reference numbers.
La
Une antenne, représentée en coupe sur la
La caractéristique du diagramme de rayonnement d'une antenne à guide d'ondes en forme de cornet circulaire (« horn » en anglais) est déterminée par le mode de transmission du guide d'ondes en cornet, qui est généralement le mode dominant ou mode TE11. Puisque le mode dominant TE11 est asymétrique autour de l'axe central du cornet, le diagramme de rayonnement de l'antenne cornet est désavantageusement asymétrique autour de l'axe central. Lors de l'utilisation d'un guide d'ondes en forme de cornet avec un réflecteur parabolique, la caractéristique de rayonnement asymétrique conduit à une réduction de l'efficacité de rayonnement de l'antenne et en une détérioration des ondes de polarisation croisée.The characteristic of the radiation pattern of a circular horn waveguide antenna ("horn") is determined by the mode of transmission of the horn waveguide, which is generally the dominant mode or mode TE 11 . Since the dominant mode TE 11 is asymmetric around the central axis of the horn, the horn antenna radiation pattern is disadvantageously asymmetrical around the central axis. When using a horn-shaped waveguide with a parabolic reflector, the asymmetric radiation characteristic leads to a reduction of the antenna radiation efficiency and a deterioration of the cross-polarization waves.
Dans un premier mode de réalisation de l'invention illustré sur les
Un moyen de réduire la diffraction des ondes apparaissant sur le bord périphérique extérieur de l'antenne est de supprimer le courant en utilisant notamment des pièges quart d'onde. Ces pièges ont la forme de gorges avec des dimensions proches du quart de la longueur d'onde considérée.One way to reduce the diffraction of the waves appearing on the outer peripheral edge of the antenna is to suppress the current, in particular using quarter-wave traps. These traps have the shape of grooves with dimensions close to a quarter of the wavelength considered.
La surface externe de la jupe 32 porte, en position latérale, des pièges à ondes 34 à surface conductrice, qui peuvent être métalliques ou en plastique métallisé. Comme montré sur la
Les pièges 34 ont pour rôle de réduire, voire de supprimer, le courant de distribution 36 sur le bord de l'antenne 30 afin de réduire la diffraction. Le principe de leur fonctionnement est basé sur le fait qu'ils produisent un déphasage d'une partie de l'onde qui est alors placée en opposition de phase avec l'onde principale et vient s'annuler.The purpose of the
Un deuxième mode de réalisation de l'invention est représenté sur la
La section de la gorge peut avoir une forme variée, par exemple une section en forme de U à fond plat comme représenté sur les
On considérera maintenant les
Sur la
Claims (10)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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FR1056366A FR2963487B1 (en) | 2010-08-02 | 2010-08-02 | PARABOLIC REFLECTOR ANTENNA |
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Publication Number | Publication Date |
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EP2416449A1 true EP2416449A1 (en) | 2012-02-08 |
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EP11176114A Withdrawn EP2416449A1 (en) | 2010-08-02 | 2011-08-01 | Parabolic-reflector antenna |
Country Status (2)
Country | Link |
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EP (1) | EP2416449A1 (en) |
FR (1) | FR2963487B1 (en) |
Cited By (9)
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WO2016061021A1 (en) | 2014-10-14 | 2016-04-21 | Ubiquiti Networks, Inc. | Signal isolation shrouds and reflectors for antenna |
US10069580B2 (en) | 2014-06-30 | 2018-09-04 | Ubiquiti Networks, Inc. | Wireless radio device alignment tools and methods |
US10136233B2 (en) | 2015-09-11 | 2018-11-20 | Ubiquiti Networks, Inc. | Compact public address access point apparatuses |
US10205471B2 (en) | 2013-10-11 | 2019-02-12 | Ubiquiti Networks, Inc. | Wireless radio system optimization by persistent spectrum analysis |
US10312598B2 (en) | 2013-02-04 | 2019-06-04 | Ubiquiti Networks, Inc. | Radio system for long-range high-speed wireless communication |
US10566676B2 (en) | 2014-04-01 | 2020-02-18 | Ubiquiti Inc. | Compact radio frequency antenna apparatuses |
US10756422B2 (en) | 2009-06-04 | 2020-08-25 | Ubiquiti Inc. | Antenna isolation shrouds and reflectors |
SE1930225A1 (en) * | 2019-06-26 | 2020-12-27 | Leax Arkivator Telecom Ab | An antenna with reduced back-lobe radiation |
US11909087B2 (en) | 2013-02-04 | 2024-02-20 | Ubiquiti Inc. | Coaxial RF dual-polarized waveguide filter and method |
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WO2015012940A1 (en) * | 2013-07-22 | 2015-01-29 | Andrew Llc | Low sidelobe reflector antenna with shield |
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US11909087B2 (en) | 2013-02-04 | 2024-02-20 | Ubiquiti Inc. | Coaxial RF dual-polarized waveguide filter and method |
US10312598B2 (en) | 2013-02-04 | 2019-06-04 | Ubiquiti Networks, Inc. | Radio system for long-range high-speed wireless communication |
US10819037B2 (en) | 2013-02-04 | 2020-10-27 | Ubiquiti Inc. | Radio system for long-range high-speed wireless communication |
US11804864B2 (en) | 2013-10-11 | 2023-10-31 | Ubiquiti Inc. | Wireless radio system optimization by persistent spectrum analysis |
US11057061B2 (en) | 2013-10-11 | 2021-07-06 | Ubiquiti Inc. | Wireless radio system optimization by persistent spectrum analysis |
US10205471B2 (en) | 2013-10-11 | 2019-02-12 | Ubiquiti Networks, Inc. | Wireless radio system optimization by persistent spectrum analysis |
US10623030B2 (en) | 2013-10-11 | 2020-04-14 | Ubiquiti Inc. | Wireless radio system optimization by persistent spectrum analysis |
US11978945B2 (en) | 2014-04-01 | 2024-05-07 | Ubiquiti Inc. | Compact radio frequency antenna apparatuses |
US11196141B2 (en) | 2014-04-01 | 2021-12-07 | Ubiquiti Inc. | Compact radio frequency antenna apparatuses |
US10566676B2 (en) | 2014-04-01 | 2020-02-18 | Ubiquiti Inc. | Compact radio frequency antenna apparatuses |
US11296805B2 (en) | 2014-06-30 | 2022-04-05 | Ubiquiti Inc. | Wireless radio device alignment tools and methods |
US10812204B2 (en) | 2014-06-30 | 2020-10-20 | Ubiquiti Inc. | Wireless radio device alignment tools and methods |
US10367592B2 (en) | 2014-06-30 | 2019-07-30 | Ubiquiti Networks, Inc. | Wireless radio device alignment tools and methods |
US11736211B2 (en) | 2014-06-30 | 2023-08-22 | Ubiquiti Inc. | Wireless radio device alignment tools and methods |
US10069580B2 (en) | 2014-06-30 | 2018-09-04 | Ubiquiti Networks, Inc. | Wireless radio device alignment tools and methods |
CN109244663A (en) * | 2014-10-14 | 2019-01-18 | 优倍快网络公司 | Chokes guard apparatus for antenna system |
WO2016061021A1 (en) | 2014-10-14 | 2016-04-21 | Ubiquiti Networks, Inc. | Signal isolation shrouds and reflectors for antenna |
EP3207592A4 (en) * | 2014-10-14 | 2018-05-23 | Ubiquiti Networks, Inc. | Signal isolation shrouds and reflectors for antenna |
CN105762529A (en) * | 2014-10-14 | 2016-07-13 | 优倍快网络公司 | Parabolic antenna reflection device, installing method thereof, and choke shroud |
US10757518B2 (en) | 2015-09-11 | 2020-08-25 | Ubiquiti Inc. | Compact public address access point apparatuses |
US10136233B2 (en) | 2015-09-11 | 2018-11-20 | Ubiquiti Networks, Inc. | Compact public address access point apparatuses |
SE1930225A1 (en) * | 2019-06-26 | 2020-12-27 | Leax Arkivator Telecom Ab | An antenna with reduced back-lobe radiation |
SE544567C2 (en) * | 2019-06-26 | 2022-07-19 | Leax Arkivator Telecom Ab | An antenna with reduced back-lobe radiation |
Also Published As
Publication number | Publication date |
---|---|
FR2963487B1 (en) | 2013-03-22 |
FR2963487A1 (en) | 2012-02-03 |
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