EP1540768B1 - Broadband helical antenna - Google Patents

Broadband helical antenna Download PDF

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Publication number
EP1540768B1
EP1540768B1 EP03797356A EP03797356A EP1540768B1 EP 1540768 B1 EP1540768 B1 EP 1540768B1 EP 03797356 A EP03797356 A EP 03797356A EP 03797356 A EP03797356 A EP 03797356A EP 1540768 B1 EP1540768 B1 EP 1540768B1
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EP
European Patent Office
Prior art keywords
radiating
parasitic
wires
antenna
strands
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Expired - Lifetime
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EP03797356A
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German (de)
French (fr)
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EP1540768A1 (en
Inventor
Ala Sharaiha
Yoann Letestu
Jean-Christophe Louvigne
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Universite de Rennes 1
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Universite de Rennes 1
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/362—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith for broadside radiating helical antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q11/00—Electrically-long antennas having dimensions more than twice the shortest operating wavelength and consisting of conductive active radiating elements
    • H01Q11/02—Non-resonant antennas, e.g. travelling-wave antenna
    • H01Q11/08—Helical antennas

Definitions

  • the field of the invention is that of broadband antennas and hemispherical or quasi-hemispherical radiation pattern. More specifically, the invention relates to helical antennas of this type.
  • the antenna of the invention finds particular applications in the context of mobile satellite communications between fixed users and / or mobiles of any type, for example aeronautical, maritime or terrestrial.
  • satellite communication systems eg INMARSAT, INMARSAT-M, GLOBALSTAR (registered trademarks), .
  • PCS personal communications systems
  • the very different incidences of signals received or emitted require the antennas to have a hemispherical or quasi-hemispherical coverage pattern.
  • the polarization must be circular (left or right) with a ratio of less than 5 dB in the useful band.
  • the invention can find applications in all systems requiring the use of a wide band and a circular polarization.
  • the antennas must in fact have the preceding characteristics either in a very wide bandwidth, of the order of 10% or more, or in two neighboring sub-bands respectively corresponding to the reception and the reception. 'program.
  • a quadrifilar helical antenna is formed of four radiating strands.
  • This antenna called printed quadrifilar helix antenna (HQI)
  • HQI printed quadrifilar helix antenna
  • HQI bilayer antennas These antennas are formed by the concentric "nesting" of two coaxial, electromagnetically coupled, quadrifilar resonant propellers. The assembly functions as two coupled resonant circuits, the coupling of which separates the resonant frequencies. This gives a two-layer resonant quadrifilar helix antenna, according to the technique described in FR - 89 14952 .
  • This technique has the advantage of requiring a single power system, and allowing dual band or wide band operation.
  • the radiating strands are printed on a dielectric substrate of small thickness, and then wound on a cylindrical support that is transparent from the radio point of view.
  • the four strands of the helix are open or short-circuited at one end and electrically connected at the other end.
  • This antenna requires a power supply circuit, which ensures the excitation of the different antenna strands by signals of the same amplitude in phase quadrature.
  • This function can be performed from 3dB -90 ° coupler structures and a hybrid ring.
  • the assembly can be made in printed circuit and placed at the base of the antennas. This gives a simple but bulky power supply.
  • the antenna including its power supply
  • the antenna to be of as small a size and weight as possible, and to have the lowest possible cost.
  • the invention particularly aims to overcome these various disadvantages of the state of the art.
  • an object of the invention is to provide a resonant helical antenna having a wide bandwidth, which can cover, for example, the transmission band and the reception band of a communication system.
  • an object of the invention is to provide such a helical antenna having a large bandwidth (greater than that obtained according to the prior art) in each subband, when two subbands are provided.
  • Another object of the invention is to provide such an antenna whose dimensions, performance and cost are acceptable for portable terminals of terrestrial cellular systems.
  • Another object of the invention is to provide a reduced size antenna while having a broadband operation.
  • An object of the invention is also to provide a relatively simple antenna to manufacture, and therefore low cost.
  • Yet another object of the invention is to provide a technical alternative to the solutions of the prior art.
  • the helical antenna is remarkable in that each of the parasitic strands is connected to the ground.
  • the helical antenna is remarkable in that the radiating strands and the parasitic strands are printed on a substrate.
  • the helical antenna can be made according to a manufacturing method that is simple, effective and at a low cost.
  • the antenna is remarkable in that each of the radiating strands is associated with a parasitic strand of width less than the radiating strand.
  • an inductive behavior corresponding to a radiating strand and in particular to its length
  • an overall capacitive behavior corresponding to the association of a radiating strand and a parasitic strand and depending on the distance between these two strands and the ratio between their width
  • the parasitic strand being preferably of small width.
  • the helical antenna is remarkable in that the ratio between the width of each of the parasitic strands and the width of the associated radiating strand is less than or equal to 0.15.
  • the performance of the antenna is optimal especially in the neighboring bands of 1 GHz.
  • the helical antenna is remarkable in that each of the parasitic strands is positioned relative to the associated radiating strand so as to optimize the coupling between the parasitic strand and the associated radiating strand.
  • a parasitic strand and the associated radiating strand are positioned to optimize the bandwidth, an optimum coupling being, if it exists, depending on the distance separating them.
  • the antenna has a better adaptation.
  • the helical antenna is remarkable in that each of the parasitic strands is further away from the associated radiating strand than from at least one of the other radiating strands.
  • optimization of the coupling between the parasitic strand and the associated radiating strand is often obtained by moving the parasitic strand away from the associated radiating strand; thus, the more the parasitic strand and the associated radiating strand are distant, the wider the radiation band of the antenna.
  • the helical antenna is remarkable in that each of the parasitic strands is parallel to the radiating strand with which it is associated.
  • each of the parasitic strands and associated radiating strands have a capacitive effect.
  • the helical antenna is remarkable in that each of the parasitic strands has substantially the same length as the radiating strand with which it is associated.
  • the antenna is relatively simple to make (and in particular simpler than if the connection to the ground at one end of the parasitic strand was, for example, in the middle of the cylinder).
  • the helical antenna is remarkable in that one of the ends of each of the radiating strands is connected by a conductive connection to one of the ends of the radiating strand to which the parasitic strand is associated.
  • the parasitic strands and the associated radiating strands may be etched on the same side of the substrate, the other side of the substrate then being available for another use (for example, for etching additional strands or another helical antenna ).
  • the helical antenna is remarkable in that one of the ends of each of the radiating strands is connected by coupling to one of the ends of the radiating strand to which the parasitic strand is associated.
  • the helical antenna is remarkable in that the radiating strands are printed on a first face of a substrate and in that the stray strands are printed on a second face of the substrate.
  • the manufacture of the antenna is simplified since the power supply (connected in particular to a radiating strand) and the mass (connected in particular to a parasitic strand) are not necessarily present on the same side of the substrate.
  • Metallic holes allowing the passage of the mass on the side of the power supply are not essential.
  • the helical antenna is remarkable in that at least one parasitic strand and a neighboring radiating strand of the radiating strand to which the parasitic strand is associated overlap.
  • the distance between a parasitic strand and the associated radiating strand is greater than that separating two neighboring radiating strands. This allows in particular to obtain more margin for the adjustment of the coupling between a parasitic strand and the associated radiating strand and thus to find more easily an optimum for improving the bandwidth.
  • the helical antenna is remarkable in that the end of the radiating strands not connected to a parasitic strand is connected to a line of attack of a supply circuit.
  • the helical antenna is remarkable in that at least one of the helices is a quadrifilar helix comprising four strands.
  • the opening of the antenna is very wide, the radiation pattern is almost hemispherical.
  • the helical antenna is remarkable in that the radiating strands forming a helix all have the same dimensions and in that the parasitic strands all have the same dimensions.
  • the strands have the same distribution of current out of phase by 90 °.
  • the helical antenna is remarkable in that at least one of the radiating and / or parasitic strands is formed of at least two segments, the winding angles of at least two of the segments being different and determined randomly or pseudo-randomly using global optimization means.
  • the helical antenna is remarkable in that at least one of the radiating and / or parasitic strands has a variable width, varying regularly and monotonically between a maximum width and a minimum width.
  • the helical antenna is remarkable in that the radiating strands have a length substantially different from a multiple of the wavelength corresponding to the average frequency of the antenna transmission band, divided by 4.
  • Figures 1 and 2 show a conventional quadrilifine helix antenna, as already discussed in the preamble. It comprises four strands 11 1 to 11 4 of length L 2 and width d. These radiating strands are printed on a dielectric substrate 12 of small thickness then wound on a cylindrical support 13 radially transparent, of radius r , circumference c and axial length L1, and ⁇ being the winding angle.
  • the antenna requires a power supply circuit which ensures the excitation of the different strands by signals of the same amplitude and in phase quadrature.
  • This function can be obtained from 3dB -90 ° coupler structures and a hybrid ring, made in a printed circuit and placed at the base of the antennas.
  • FIG. 3 shows an example of a propeller 30 according to the invention, in its expanded form.
  • the HQI antenna 30 thus comprises 4 regularly spaced conducting radiating strands 31 1 to 31 4 , printed on a substrate 32 and having a width equal to Wa.
  • the four strands 31 1 to 31 4 are folded on themselves at one of their end respectively 36 1 to 36 4 , each forming a parasitic strand respectively 34 1 to 34 4 and connected at the other end to the lines of attack of the supply circuit 33.
  • the parasitic strands 34 1 to 34 4 have a width W br less than the width, W a , radiating strands to ensure broadband operation of the antenna.
  • the parasitic strands 34 1 to 34 4 are connected to the ground 35 at the end opposite the end respectively 36 1 to 36 4 .
  • the width, W br , parasitic strands and the width, W a , radiating strands are constant.
  • the antenna 30 is then wound on a cylindrical support, as shown in Figure 4, which has a front view of the antenna wound on its cylindrical support.
  • the antenna band widens as the distance d increases.
  • the parasitic strand is therefore close to the neighboring radiating strand.
  • FIG. 5 shows the measured ROS 52 as a function of the frequency 50 (expressed in GHz in the figure) measured at the input of a radiating strand for the antenna 30 illustrated with reference to FIGS. 3 and 4, the others being charged under 50 ⁇ .
  • the antennas are measured at center frequency F1 equal to 1.5 GHz.
  • the folded-over HQI antenna according to the invention, an adaptation of the HQI antenna of less than -10 dB is obtained over the interval from 1.27 GHz to 1.65 GHz, ie a bandwidth that reaches 26%.
  • the HQI antenna has a significant increase in bandwidth.
  • the folded printed quadrifilar helix antenna which each parasitic strand is connected to ground allows the transmission and / or reception in a wide bandwidth or in two different sub-bands each having a wide bandwidth.
  • the technique of the invention therefore gives a significant increase in the bandwidth.
  • This produces a printed quadrilateral helix antenna operating in a wide bandwidth and / or in two different sub-bands each having a wide bandwidth, and whose height is reduced.
  • the folded quadrifilar helix antenna folded with parasitic strands connected to the ground therefore allows an increase in the bandwidth of the antenna without reducing the lengths of strands.
  • Figure 6 is a Smith chart representing the input impedance 60 of an antenna according to the invention standardized at 50 Ohms.
  • a loop 61 on the curve 60 is derived from the coupling and gives the wide band since present inside a circle 62 corresponding to a ROS less than or equal to 2.
  • FIG. 7a shows an example of a helix 70 according to a variant of the invention, in its developed form.
  • the HQI antenna 70 thus comprises four regularly spaced conductive radiating strands 71 1 to 71 4 printed on a first face of the substrate 72 and of width equal to W a .
  • the four strands 71 1 to 71 4 are connected at one end to the leading lines of the supply circuit 73.
  • Strands 74 1 to 74 4 are printed parallel to the radiating strands on a second face of the substrate 72 opposite the first face.
  • the parasitic strands 74 1 to 74 4 are connected to the ground 75 at one of their end respectively 71 1 to 71 4 .
  • Each of parasitic strands 74 1 to 74 4 is coupled by its end 75 1 to 75 4, respectively, not connected to ground 75, at the end not connected to the supply of strand respectively 71 1 to 71 4 to which it is associated.
  • the parasitic strands 74 1 to 74 4 have a width W br less than or equal to and preferably much lower (in a ratio W br / W a less than 0.15), the width W a , radiating strands in order to guarantee a broadband operation of the antenna.
  • the width, W br, parasitic strands and the width, W a , radiating strands are constant.
  • the distance separating a parasitic strand and the associated radiating strand is not limited by the distance separating two radiating strands.
  • the distance between a parasitic strand and the radiating strand may be greater than the distance separating two radiating strands.
  • the coupling between a parasitic strand and the associated radiating strand and therefore the bandwidth can then be improved. We then have more possibilities in the search for optimum coupling.
  • FIG. 7b illustrates in detail the end 751 of the radiating strand 711 coupled to the parasitic strand 741.
  • each of the parasitic strands and the associated radiating strand overlap on both sides of the substrate 72 over a distance E between 0 and the distance d separating the parasitic strand from the associated radiating strand.
  • the other characteristics of the antenna 70 (winding around a cylindrical support, dimensions of the strands and the antenna, etc.) being similar to that of the antenna 30 of FIGS. 3 and 4, will not be described further. .
  • FIG. 8 shows an example of an antenna 80 according to a variant of the invention according to which radiating strands 81 1 to 81 4 are of variable width.
  • Each of the radiating strands 81 1 to 81 4 is connected at one of its ends to a parasitic strand 84 1 to 84 4 .
  • the width of the parasitic strands is constant and each of the parasitic strands is parallel to a longitudinal median line of the associated radiating strand (illustrated, for example, by the line 87 corresponding to the strand 81 1 ).
  • each of the radiating strands of the antenna 80 has a minimum width W a1 equal to 2 mm and a maximum width W a2 equal to 16 mm.
  • the characteristics of the antenna 80 being similar to those of the antenna 30 illustrated with reference to FIGS. 3 and 4, they will not be described further.
  • the parasitic strands of a helical antenna are coupled and not directly connected to radiating strands of variable width, similar to the strands 81 1 to 81 4 of the antenna 80 (according to a similar coupling to that of the radiating and parasitic strands of the antenna 70).
  • the width of the parasitic strands is variable, the longitudinal median lines of each of the parasitic strands and the associated radiating strand are parallel.
  • the parasitic strands are parallel to one of the sides of the radiating strands.
  • a parasitic strand parallel to an adjacent radiating strand makes it possible, in particular, to move this parasitic strand away from the associated radiating strand while bringing it closer to the adjacent strand, thereby increasing the capacitive effect and the bandwidth of the antenna.
  • the parasitic strands and the radiating strands are connected by a single point of connection.
  • FIG. 9a shows an example of antenna 90 according to another variant of the invention having radiating strands 91 1 to 91 4 forming a broken line.
  • Each of the radiating strands 91 1 to 91 4 is connected at one of its ends to a parasitic strand 94 1 to 94 4 .
  • Each radiating strand 91 1 to 91 4 (or at least some) of the HQI antenna is decomposed into a limited number of segments. According to the mathematical expressions linking the geometrical parameters of a helical antenna, one observes that a modification of the winding angle influences the pitch of the antenna, thus the axial length.
  • the winding angle ⁇ is also a parameter influencing the radiation pattern of an HQI antenna (opening angle at 3dB, ellipticity ratio). Therefore, to choose the different angles ⁇ adequate, a global optimization program such as simulated annealing or the genetic algorithm can be used.
  • the synthesis is performed on the main and crossed polarization radiation diagrams by introducing a template defined by the desired amplitude levels and aperture angles -3dB.
  • this template makes it possible to perfectly control the angles of opening at -3 dB, as well as the rejection of the inverse polarization and therefore the ellipticity ratio.
  • the variables to be optimized are the different winding angles of the strands of the HQI antenna.
  • the algorithm will give the angles ⁇ i optimum.
  • the radiating strands 91 1 and parasite 94 1 and in particular the segments that make up the radiating strand 91 1 are illustrated in more detail with respect to FIG. 9b.
  • the parasitic strand 94 1 is parallel to an inner tangent 97 (i.e. between the radiating strand 91 1 and the associated parasitic strand 94 1 ) of the radiating strand 91 1 .
  • one or more parasitic strands are parallel to an outer tangent (that is to say located on the opposite side to the parasitic strand) of the associated radiating strand (which makes it possible to bring the strand strand closer to a strand adjacent neighbor) or at a median line of the associated radiating strand.
  • one or more parasitic strands form a broken line.
  • each of these parasitic strands has the same number of segments as the associated radiating strand and each of the parasitic strand segments has the same length and is parallel to a corresponding segment on the associated radiating strand (thus, besides a different width, the parasitic strand and the associated radiating strand have the same shape), which makes it possible to position a parasitic strand very close to an adjacent radiating strand.
  • the parasitic strands of a helical antenna are connected by coupling (and not directly) to radiating strands forming a broken line in a manner similar to the coupling connection presented with reference to FIGS. 7a and 7b.
  • the width of the parasitic strands may take any value less than that of an associated radiating strand and preferably of the order of one-eighth that of an associated radiating strand.
  • the invention can be applied to any type of helical antenna, and not only to quadrilateral antennas.
  • the strands do not all have identical dimensions.
  • the antenna is printed flat, then wound on a support to form the antenna.
  • the substrate for receiving the printed elements can be made directly in its final cylindrical form. In this case, the printing of the strands and the feed structure is performed directly on the cylinder.
  • the antenna of the invention also lends itself to the realization of antenna arrays.
  • the technique of the invention is compatible with techniques for reducing the size of the antenna, such as in particular that proposed in the patent application in the patent document.
  • FR-0011830 on behalf of France Telecom (helical antenna with variable pitch) or to increase the bandwidth, for example, according to a technique proposed in the patent document FR-0011843 , on behalf of France Telecom (helical antenna with wide strands variable).
  • the presence of variable pitch and / or the variation of width can be applied on all the strands, or selectively on some of them.

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Abstract

The wide band helix antenna has helices forming radiating strips (31). Each radiating strip has an associated parasitic strip (34) and having a width equal to or lower than the radiating strip, producing an increased antenna pass band.

Description

Le domaine de l'invention est celui des antennes à large bande passante et à diagramme de rayonnement hémisphérique ou quasi-hémisphérique. Plus précisément, l'invention concerne les antennes hélicoïdales de ce type.The field of the invention is that of broadband antennas and hemispherical or quasi-hemispherical radiation pattern. More specifically, the invention relates to helical antennas of this type.

L'antenne de l'invention trouve notamment des applications dans le cadre des communications mobiles par satellite entre des utilisateurs fixes et/ou des mobiles de tout type, par exemple aéronautiques, maritimes ou terrestres. Dans ce domaine, plusieurs systèmes de communication par satellite sont mis en oeuvre, ou sont actuellement en cours de développement (par exemple les systèmes INMARSAT, INMARSAT-M, GLOBALSTAR (marques déposées),...). Ces antennes présentent également un intérêt dans le déploiement des systèmes de communications personnelles (PCS) par satellites géostationnaires.The antenna of the invention finds particular applications in the context of mobile satellite communications between fixed users and / or mobiles of any type, for example aeronautical, maritime or terrestrial. In this field, several satellite communication systems are implemented, or are currently under development (eg INMARSAT, INMARSAT-M, GLOBALSTAR (registered trademarks), ...). These antennas are also of interest in the deployment of personal communications systems (PCS) by geostationary satellites.

Ces systèmes ont pour but de fournir aux utilisateurs terrestres des nouveaux services de communications (multimédia, téléphonie) via les satellites. A l'aide de satellites géostationnaires ou défilants, ils permettent d'obtenir une couverture terrestre globale. Ils doivent être similaires aux systèmes cellulaires terrestres en termes de coût, de performance et de taille. Ainsi, l'antenne située sur le terminal de l'utilisateur est un élément clé du point de vue de la réduction de la taille.These systems are intended to provide terrestrial users with new communications services (multimedia, telephony) via satellites. With the help of geostationary or moving satellites, they make it possible to obtain a global terrestrial coverage. They must be similar to terrestrial cellular systems in terms of cost, performance and size. Thus, the antenna located on the user's terminal is a key element from the point of view of reducing the size.

De tels systèmes sont notamment décrits dans les documents d'Howard Feldman, D.V. Ramana : « An introduction to Inmarsat's new mobile multimedia service », Sixth International Mobile Satellite Conference, Ottawa, June 1999 , et de J.V. Evans : « Satellite systems for personal communications », IEEE A-P Magazine, Vol. 39, n° 3, June 1997 .Such systems are notably described in the documents by Howard Feldman, DV Ramana: "An introduction to Inmarsat's new mobile multimedia service", Sixth International Mobile Satellite Conference, Ottawa, June 1999 , and of JV Evans: "Satellite systems for personal communications," IEEE AP Magazine, Vol. 39, No. 3, June 1997 .

Pour tous ces systèmes, qui prévoient des liaisons avec des satellites géostationnaires, les incidences très différentes des signaux reçus ou émis imposent aux antennes de posséder un diagramme de rayonnement à couverture hémisphérique ou quasi-hémisphérique. De plus la polarisation doit être circulaire (gauche ou droite) avec un rapport inférieur à 5 dB dans la bande utile.For all these systems, which provide links with geostationary satellites, the very different incidences of signals received or emitted require the antennas to have a hemispherical or quasi-hemispherical coverage pattern. In addition, the polarization must be circular (left or right) with a ratio of less than 5 dB in the useful band.

Plus généralement, l'invention peut trouver des applications dans tous les systèmes nécessitant l'emploi d'une large bande et une polarisation circulaire.More generally, the invention can find applications in all systems requiring the use of a wide band and a circular polarization.

Dans ces différents domaines d'application, les antennes doivent en effet présenter les caractéristiques précédentes soit dans une bande passante très large, de l'ordre de 10 % ou plus, soit dans deux sous-bandes voisines correspondant respectivement à la réception et à l'émission.In these different fields of application, the antennas must in fact have the preceding characteristics either in a very wide bandwidth, of the order of 10% or more, or in two neighboring sub-bands respectively corresponding to the reception and the reception. 'program.

On connaît déjà, par le document de brevet FR-89 14952 au nom de France Telecom (marque déposée), un type d'antenne quadrifilaire en hélice particulièrement adapté à de telles applications. Une antenne quadrifilaire est formée de quatre brins rayonnants.It is already known from the patent document FR-8914952 on behalf of France Telecom (registered trademark), a type of quadrifilar helical antenna particularly suitable for such applications. A quadrifilar antenna is formed of four radiating strands.

Cette antenne, appelée antenne hélice quadrifilaire imprimée (HQI), possède des caractéristiques proches des critères énoncés, dans une bande de fréquence limitée en général à 6 ou à 8 % pour un ROS inférieur à deux.This antenna, called printed quadrifilar helix antenna (HQI), has characteristics close to the stated criteria, in a frequency band generally limited to 6 or 8% for an ROS less than two.

Un fonctionnement plus large bande peut être obtenu en utilisant des antennes HQI bicouche. Ces antennes sont formées par l' "emboîtement" concentriques de deux hélices quadrifilaires résonnantes coaxiales, couplées électromagnétiquement. L'ensemble fonctionne comme deux circuits résonnants couplés, dont le couplage écarte les fréquences de résonance. On obtient ainsi une antenne hélice quadrifilaire résonnante bicouche, selon la technique décrite dans FR - 89 14952 .Broader band operation can be achieved using HQI bilayer antennas. These antennas are formed by the concentric "nesting" of two coaxial, electromagnetically coupled, quadrifilar resonant propellers. The assembly functions as two coupled resonant circuits, the coupling of which separates the resonant frequencies. This gives a two-layer resonant quadrifilar helix antenna, according to the technique described in FR - 89 14952 .

Cette technique présente l'avantage de nécessiter un seul système d'alimentation, et de permettre un fonctionnement double bande ou large bande.This technique has the advantage of requiring a single power system, and allowing dual band or wide band operation.

En revanche, elle présente l'inconvénient de nécessiter la réalisation de deux circuits imprimés et imbriqués, et, dans le fonctionnement double bande, de n'offrir qu'une faible largeur de bande dans chaque sous-bande. En fonctionnement large bande, la largeur de bande obtenue reste limitée.On the other hand, it has the drawback of requiring the production of two printed and interleaved circuits, and, in dual band operation, of offering only a small bandwidth in each sub-band. In broadband operation, the bandwidth obtained remains limited.

Un autre exemple de réalisation est décrit en détail dans le document " Analysis of quadrifilar resonant helical antenna for mobile communications" (analyse de l'antenne hélice quadrifilaire résonnante pour les communications avec les mobiles), par A. Sharaiha et C. Terret (IEE - Proceedings H, vol. 140, n° 4, août 1993 ).Another embodiment is described in detail in the document " Analysis of quadrifilar resonant helical antenna for mobile communications "(analysis of the resonant quadrifilar helix antenna for mobile communications), by A. Sharaiha and C. Terret (IEE - Proceedings H, vol 140, n ° 4, August 1993 ).

Selon ce mode de réalisation, les brins rayonnants sont imprimés sur un substrat diélectrique de faible épaisseur, puis enroulés sur un support cylindrique transparent du point de vue radioélectrique. Les quatre brins de l'hélice sont ouverts ou court-circuités à une extrémité et connectés électriquement à l'autre extrémité.According to this embodiment, the radiating strands are printed on a dielectric substrate of small thickness, and then wound on a cylindrical support that is transparent from the radio point of view. The four strands of the helix are open or short-circuited at one end and electrically connected at the other end.

Cette antenne nécessite un circuit d'alimentation, qui assure l'excitation des différents brins d'antenne par des signaux de même amplitude en quadrature de phase. Cette fonction peut être réalisée à partir de structures de coupleurs 3dB -90° et d'un anneau hybride. L'ensemble peut être réalisé en circuit imprimé et placé à la base des antennes. On obtient ainsi une alimentation simple mais encombrante.This antenna requires a power supply circuit, which ensures the excitation of the different antenna strands by signals of the same amplitude in phase quadrature. This function can be performed from 3dB -90 ° coupler structures and a hybrid ring. The assembly can be made in printed circuit and placed at the base of the antennas. This gives a simple but bulky power supply.

Comme mentionné plus haut, il est souhaitable que l'antenne (incluant son alimentation) soit de taille et de poids les plus réduits possible, et qu'elle ait un coût le plus faible possible.As mentioned above, it is desirable for the antenna (including its power supply) to be of as small a size and weight as possible, and to have the lowest possible cost.

Plusieurs approches visant à réduire les dimensions de l'antenne et de son système d'alimentation ont été proposées. On peut notamment citer, à titres d'exemples, les solutions présentées :

  • dans le document de brevet FR-96 03698 , au nom de France Telecom (antenne hélice à alimentation large bande intégrée) ;
  • dans le document de brevet FR-0011830 , au nom de France Telecom (antenne hélicoïdale à pas variable) ;
  • dans le document de brevet FR- 0011843 , au nom de France Telecom (antenne hélicoïdale à brins de largeur variable) ; et
  • dans l'article de B. Desplanches, A. Sharaiha et C. Terret intitulé « Parametrical study of printed quadrifilar helical antennas with central dielectric rods » (Microwave and Opt. Technol. Letters, Vol. 20, N° 4, February 20, 1999 ).
Several approaches to reduce the dimensions of the antenna and its power system have been proposed. We can cite, by way of examples, the presented solutions:
  • in the patent document FR-96 03698 , on behalf of France Telecom (helix antenna with integrated broadband power supply);
  • in the patent document FR-0011830 , on behalf of France Telecom (helical antenna with variable pitch);
  • in the patent document FR-0011843 , on behalf of France Telecom (helical antenna with strands of variable width); and
  • in the article of B. Desplanches, A. Sharaiha and C. Terret entitled "Parametrical study of printed quadrifilar helical antennas with central dielectric rods" (Microwave and Opt.Technol Letters, Vol 20, No. 4, February 20, 1999 ).

Néanmoins, ces antennes n'offrent pas une très grande largeur de bande.Nevertheless, these antennas do not offer a very large bandwidth.

On connaît également dans l'état de la technique des antennes à hélice à éléments rayonnants repliés illustrées respectivement dans un document de brevet US-6,229,499 de la société XM Satellite Radio (marque déposée) et dans un document de brevet US-6,278,414 de la société Qualcomm (marque déposée). Ces antennes possèdent des éléments rayonnants qui sont en partie repliés sur eux-mêmes permettant, ainsi, de réduire leur hauteur. Néanmoins, ces antennes présentent l'inconvénient d'être à bande étroite.Also known in the state of the art radiating antenna propeller with folded radiating elements illustrated respectively in a patent document US 6229499 XM Satellite Radio (registered trademark) and in a patent document US 6278414 from the company Qualcomm (registered trademark). These antennas have radiating elements which are partly folded back on themselves, thus making it possible to reduce their height. Nevertheless, these antennas have the disadvantage of being narrowband.

L'invention a notamment pour objectif de pallier ces divers inconvénients de l'état de la technique.The invention particularly aims to overcome these various disadvantages of the state of the art.

Plus précisément, un objectif de l'invention est de fournir une antenne hélicoïdale résonante présentant une large bande passante, pouvant couvrir, par exemple, la bande d'émission et la bande de réception d'un système de communication.More specifically, an object of the invention is to provide a resonant helical antenna having a wide bandwidth, which can cover, for example, the transmission band and the reception band of a communication system.

Notamment, un objectif de l'invention est de fournir une telle antenne hélicoïdale présentant une largeur de bande importante (supérieure à celle obtenue selon l'art antérieur) dans chaque sous-bande, lorsque deux sous-bandes sont prévues.In particular, an object of the invention is to provide such a helical antenna having a large bandwidth (greater than that obtained according to the prior art) in each subband, when two subbands are provided.

Un autre objectif de l'invention est de fournir une telle antenne dont les dimensions, les performances et le coût de revient sont acceptables pour des terminaux portables de systèmes cellulaires terrestres.Another object of the invention is to provide such an antenna whose dimensions, performance and cost are acceptable for portable terminals of terrestrial cellular systems.

Un autre objectif de l'invention est de fournir une antenne de taille réduite tout en ayant un fonctionnement en large bande.Another object of the invention is to provide a reduced size antenna while having a broadband operation.

Un objectif de l'invention est également de fournir une antenne relativement simple à fabriquer, et par conséquent de faible coût.An object of the invention is also to provide a relatively simple antenna to manufacture, and therefore low cost.

Encore un autre objectif de l'invention est de fournir une alternative technique aux solutions de l'art antérieur.Yet another object of the invention is to provide a technical alternative to the solutions of the prior art.

Ces objectifs, ainsi que d'autres qui apparaîtront par la suite, sont atteints selon l'invention à l'aide d'une antenne hélicoïdale selon la revendication 1.These objectives, as well as others which will appear later, are achieved according to the invention with the aid of a helical antenna according to claim 1.

Préférentiellement, l'antenne hélicoïdale est remarquable en ce que chacun des brins parasites est relié à la masse.Preferably, the helical antenna is remarkable in that each of the parasitic strands is connected to the ground.

Ainsi, on optimise le fonctionnement de l'antenne et notamment des brins parasites.Thus, it optimizes the operation of the antenna and in particular parasitic strands.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que les brins rayonnants et les brins parasites sont imprimés sur un substrat.According to one particular characteristic, the helical antenna is remarkable in that the radiating strands and the parasitic strands are printed on a substrate.

De cette manière, l'antenne hélicoïdale peut être réalisée selon un mode de fabrication à la fois simple, efficace et à faible coût.In this way, the helical antenna can be made according to a manufacturing method that is simple, effective and at a low cost.

L'antenne est remarquable en ce que chacun des brins rayonnants est associé à un brin parasite de largeur inférieure au brin rayonnant.The antenna is remarkable in that each of the radiating strands is associated with a parasitic strand of width less than the radiating strand.

Ainsi, on obtient un comportement selfique (correspondant à un brin rayonnant et notamment à sa longueur) associé à un comportement capacitif global (correspondant à l'association d'un brin rayonnant et d'un brin parasite et dépendant de la distance entre ces deux brins et du rapport entre leur largeur), le brin parasite étant préférentiellement de faible largeur.Thus, one obtains an inductive behavior (corresponding to a radiating strand and in particular to its length) associated with an overall capacitive behavior (corresponding to the association of a radiating strand and a parasitic strand and depending on the distance between these two strands and the ratio between their width), the parasitic strand being preferably of small width.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que le rapport entre la largeur de chacun des brins parasites et la largeur du brin rayonnant associé est inférieur ou égal à 0,15 .According to one particular characteristic, the helical antenna is remarkable in that the ratio between the width of each of the parasitic strands and the width of the associated radiating strand is less than or equal to 0.15.

Ainsi, les performances de l'antenne sont optimales notamment dans les bandes voisines de 1 GHz.Thus, the performance of the antenna is optimal especially in the neighboring bands of 1 GHz.

Préférentiellement, l'antenne hélicoïdale est remarquable en ce que chacun des brins parasites est positionné par rapport au brin rayonnant associé de façon à optimiser le couplage entre le brin parasite et le brin rayonnant associé.Preferably, the helical antenna is remarkable in that each of the parasitic strands is positioned relative to the associated radiating strand so as to optimize the coupling between the parasitic strand and the associated radiating strand.

Ainsi, un brin parasite et le brin rayonnant associé sont positionnés de façon à optimiser la bande passante, un optimum de couplage étant, s'il existe, dépendant de la distance les séparant.Thus, a parasitic strand and the associated radiating strand are positioned to optimize the bandwidth, an optimum coupling being, if it exists, depending on the distance separating them.

Ainsi, l'antenne possède une meilleure adaptation.Thus, the antenna has a better adaptation.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que chacun des brins parasites est plus éloigné du brin rayonnant associé que de l'un au moins des autres brins rayonnants.According to one particular characteristic, the helical antenna is remarkable in that each of the parasitic strands is further away from the associated radiating strand than from at least one of the other radiating strands.

En effet, une optimisation du couplage entre le brin parasite et le brin rayonnant associé est souvent obtenue en éloignant le brin parasite du brin rayonnant associé ; ainsi, plus le brin parasite et le brin rayonnant associé sont éloignés, plus la bande de rayonnement de l'antenne est large.Indeed, optimization of the coupling between the parasitic strand and the associated radiating strand is often obtained by moving the parasitic strand away from the associated radiating strand; thus, the more the parasitic strand and the associated radiating strand are distant, the wider the radiation band of the antenna.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que chacun des brins parasites est parallèle au brin rayonnant auquel il est associé.According to one particular characteristic, the helical antenna is remarkable in that each of the parasitic strands is parallel to the radiating strand with which it is associated.

Ici, lorsqu'un brin parasite et le brin rayonnant associé sont rectilignes et de largeur constante ou variable, les deux brins sont parallèles si leurs lignes médianes longitudinales sont parallèles.Here, when a parasitic strand and the associated radiating strand are rectilinear and of constant or variable width, the two strands are parallel if their longitudinal median lines are parallel.

Ici, lorsqu'un brin parasite et/ou le brin rayonnant associé forment une ligne brisée, les deux brins sont considérés comme parallèles si l'une des trois conditions suivantes est respectée :

  • leur lignes médianes longitudinales sont parallèles ; ou
  • leur lignes tangentes extérieures et/ou intérieures suivant le sens de la longueur sont parallèles ; ou
  • chacun des segments formant le brin parasite est parallèle à un segment associé du brin rayonnant.
Here, when a parasitic strand and / or the associated radiating strand form a broken line, the two strands are considered parallel if one of the following three conditions is met:
  • their longitudinal median lines are parallel; or
  • their outer and / or inner tangent lines along the length direction are parallel; or
  • each of the segments forming the parasitic strand is parallel to an associated segment of the radiating strand.

Ainsi, chacun des brins parasites et des brins rayonnants associés présentent un effet capacitif.Thus, each of the parasitic strands and associated radiating strands have a capacitive effect.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que chacun des brins parasites présente sensiblement la même longueur que le brin rayonnant auquel il est associé.According to one particular characteristic, the helical antenna is remarkable in that each of the parasitic strands has substantially the same length as the radiating strand with which it is associated.

Ainsi, l'antenne est relativement simple à réaliser (et notamment plus simple que si la liaison à la masse à une extrémité du brin parasite se faisait, par exemple, au milieu du cylindre).Thus, the antenna is relatively simple to make (and in particular simpler than if the connection to the ground at one end of the parasitic strand was, for example, in the middle of the cylinder).

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que l'une des extrémités de chacun des brins rayonnants est reliée par une liaison conductrice à l'une des extrémités du brin rayonnant auquel le brin parasite est associé.According to one particular characteristic, the helical antenna is remarkable in that one of the ends of each of the radiating strands is connected by a conductive connection to one of the ends of the radiating strand to which the parasitic strand is associated.

Ainsi, les brins parasites et les brins rayonnants associés peuvent être gravés sur un même coté de substrat, l'autre coté du substrat étant alors disponible pour une autre utilisation (par exemple, pour la gravure de brins supplémentaires ou d'une autre antenne hélice).Thus, the parasitic strands and the associated radiating strands may be etched on the same side of the substrate, the other side of the substrate then being available for another use (for example, for etching additional strands or another helical antenna ).

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que l'une des extrémités de chacun des brins rayonnants est reliée par couplage à l'une des extrémités du brin rayonnant auquel le brin parasite est associé.According to one particular characteristic, the helical antenna is remarkable in that one of the ends of each of the radiating strands is connected by coupling to one of the ends of the radiating strand to which the parasitic strand is associated.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que les brins rayonnants sont imprimés sur une première face d'un substrat et en ce que les brins parasites sont imprimés sur une deuxième face du substrat.According to a particular characteristic, the helical antenna is remarkable in that the radiating strands are printed on a first face of a substrate and in that the stray strands are printed on a second face of the substrate.

Ainsi, la fabrication de l'antenne est simplifiée puisque l'alimentation (reliée notamment à un brin rayonnant) et la masse (reliée notamment à un brin parasite) ne sont pas nécessairement présents sur le même coté du substrat. Des trous métallisés permettant le passage de la masse du coté de l'alimentation ne sont donc pas indispensables.Thus, the manufacture of the antenna is simplified since the power supply (connected in particular to a radiating strand) and the mass (connected in particular to a parasitic strand) are not necessarily present on the same side of the substrate. Metallic holes allowing the passage of the mass on the side of the power supply are not essential.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce qu'au moins un brin parasite et un brin rayonnant voisin du brin rayonnant auquel le brin parasite est associé se chevauchent.According to a particular characteristic, the helical antenna is remarkable in that at least one parasitic strand and a neighboring radiating strand of the radiating strand to which the parasitic strand is associated overlap.

Ainsi, la distance entre un brin parasite et le brin rayonnant associé est plus grande que celle séparant deux brins rayonnants voisins. Cela permet notamment d'obtenir plus de marge pour le réglage du couplage entre un brin parasite et le brin rayonnant associé et donc de trouver plus facilement un optimum pour améliorer la bande passante.Thus, the distance between a parasitic strand and the associated radiating strand is greater than that separating two neighboring radiating strands. This allows in particular to obtain more margin for the adjustment of the coupling between a parasitic strand and the associated radiating strand and thus to find more easily an optimum for improving the bandwidth.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que l'extrémité des brins rayonnants non reliée à un brin parasite est connectée à une ligne d'attaque d'un circuit d'alimentation.According to one particular characteristic, the helical antenna is remarkable in that the end of the radiating strands not connected to a parasitic strand is connected to a line of attack of a supply circuit.

Ainsi, le fonctionnement de l'antenne est optimisé.Thus, the operation of the antenna is optimized.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce qu'au moins une des hélices est une hélice quadrifilaire, comprenant quatre brins.According to one particular characteristic, the helical antenna is remarkable in that at least one of the helices is a quadrifilar helix comprising four strands.

De cette façon, on obtient une bonne pureté de polarisation circulaire.In this way, a good purity of circular polarization is obtained.

En outre, pour certains cas, l'ouverture de l'antenne est très large, le diagramme de rayonnement étant quasi hémisphérique.In addition, for some cases, the opening of the antenna is very wide, the radiation pattern is almost hemispherical.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que les brins rayonnants formant une hélice présentent tous les mêmes dimensions et en ce que les brins parasites présentent tous les mêmes dimensions.According to a particular characteristic, the helical antenna is remarkable in that the radiating strands forming a helix all have the same dimensions and in that the parasitic strands all have the same dimensions.

Ainsi, on obtient une meilleure polarisation circulaire, la symétrie des brins étant bonne. De plus, les brins possèdent une même distribution de courant déphasée de 90°.Thus, a better circular polarization is obtained, the symmetry of the strands being good. In addition, the strands have the same distribution of current out of phase by 90 °.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce qu'au moins un des brins rayonnants et/ou parasites est formé d'au moins deux segments, les angles d'enroulement d'au moins deux des segments étant différents et déterminés de façon aléatoire ou pseudo-aléatoire à l'aide de moyens d'optimisation globale.According to one particular characteristic, the helical antenna is remarkable in that at least one of the radiating and / or parasitic strands is formed of at least two segments, the winding angles of at least two of the segments being different and determined randomly or pseudo-randomly using global optimization means.

Ainsi, la ligne formée par chacun des brins rayonnant et/ou parasites est brisée ce qui permet de réduire la taille de l'antenne tout en conservant de bonnes performances.Thus, the line formed by each of the radiating strands and / or parasitic is broken which reduces the size of the antenna while maintaining good performance.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce qu'au moins un des brins rayonnants et/ou parasites présente une largeur variable, variant de façon régulière et monotone entre une largeur maximale et une largeur minimale.According to one particular characteristic, the helical antenna is remarkable in that at least one of the radiating and / or parasitic strands has a variable width, varying regularly and monotonically between a maximum width and a minimum width.

De cette manière, l'adaptation de l'antenne est simplifiée, un paramètre supplémentaire de réglage étant disponible pour cette adaptation.In this way, the adaptation of the antenna is simplified, an additional setting parameter being available for this adaptation.

Selon une caractéristique particulière, l'antenne hélicoïdale est remarquable en ce que les brins rayonnants présentent une longueur sensiblement différente d'un multiple de la longueur d'onde correspondant à la fréquence moyenne de la bande d'émission de l'antenne, divisée par 4.According to one particular characteristic, the helical antenna is remarkable in that the radiating strands have a length substantially different from a multiple of the wavelength corresponding to the average frequency of the antenna transmission band, divided by 4.

Ainsi, on peut jouer sur l'ouverture de l'antenne contrairement aux antennes connues du type dipôles avec brin parasite, qui ont une longueur multiple de λ/4 où λ représente la longueur d'onde d'émission de l'antenne.Thus, one can play on the opening of the antenna unlike known antennas of the parasitic stray dipole type, which have a length multiple of λ / 4 where λ represents the emission wavelength of the antenna.

D'autres caractéristiques et avantages de l'invention apparaîtront plus clairement à la lecture de la description suivante d'un mode de réalisation préférentiel de l'invention, donné à titre de simple exemple illustratif et non limitatif, et des dessins annexés parmi lesquels :

  • Les figures 1 et 2 illustrent une antenne hélice quadrilifaire de type connu, à brins classiques de largeur constante, respectivement lorsque l'hélice est développé (figure 1) et lorsqu'elle est enroulée sur un support cylindrique (figure 2) ;
  • La figure 3 est un exemple d'hélice selon l'invention, sous sa forme développée ;
  • La figure 4 présente une vue de face de l'hélice de la figure 3, enroulée sur son support cylindrique ;
  • La figure 5 illustre un exemple de ROS mesuré à l'entrée d'un brin pour une antenne selon l'invention ;
  • La figure 6 est une abaque de Smith représentant l'impédance d'entrée d'une antenne selon l'invention ;
  • Les figures 7a et 7b illustrent une variante de l'invention selon laquelle des brins rayonnants et des brins parasites associés sont couplés en étant imprimés sur deux faces opposées d'un substrat ;
  • La figure 8 présente un exemple d'antenne selon une variante de l'invention selon laquelle des brins rayonnants sont de largeur variable ; et
  • Les figures 9a et 9b montrent un exemple d'antenne selon une autre variante de l'invention présentant des brins rayonnants formant une ligne brisée.
Other characteristics and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of a simple illustrative and nonlimiting example, and the appended drawings among which:
  • FIGS. 1 and 2 illustrate a quadriliform helical antenna of known type, with conventional strands of constant width, respectively when the helix is developed (FIG. 1) and when it is wound on a cylindrical support (FIG. 2);
  • Figure 3 is an example of a propeller according to the invention, in its expanded form;
  • Figure 4 shows a front view of the helix of Figure 3, wound on its cylindrical support;
  • FIG. 5 illustrates an example of ROS measured at the input of a strand for an antenna according to the invention;
  • Figure 6 is a Smith chart showing the input impedance of an antenna according to the invention;
  • FIGS. 7a and 7b illustrate a variant of the invention according to which radiating strands and associated strands are coupled by being printed on two opposite faces of a substrate;
  • FIG. 8 shows an example of an antenna according to a variant of the invention according to which radiating strands are of variable width; and
  • Figures 9a and 9b show an example of antenna according to another embodiment of the invention having radiating strands forming a broken line.

Les figures 1 et 2 présentent une antenne hélice quadrilifaire classique, telle que déjà discutée en préambule. Elle comprend quatre brins 111 à 114 de longueur L2 et de largeur d. Ces brins rayonnants sont imprimés sur un substrat diélectrique 12 de faible épaisseur enroulé ensuite sur un support cylindrique 13 transparent du point de vue radioélectrique, de rayon r, de circonférence c et de longueur axiale L1, et α étant l'angle d'enroulement.Figures 1 and 2 show a conventional quadrilifine helix antenna, as already discussed in the preamble. It comprises four strands 11 1 to 11 4 of length L 2 and width d. These radiating strands are printed on a dielectric substrate 12 of small thickness then wound on a cylindrical support 13 radially transparent, of radius r , circumference c and axial length L1, and α being the winding angle.

Classiquement, l'antenne nécessite un circuit d'alimentation qui assure l'excitation des différents brins par des signaux de même amplitude et en quadrature de phase. Cette fonction peut être obtenue à partir de structures de coupleurs 3dB -90° et d'un anneau hybride, réalisée en circuit imprimé et placé à la base des antennes.Conventionally, the antenna requires a power supply circuit which ensures the excitation of the different strands by signals of the same amplitude and in phase quadrature. This function can be obtained from 3dB -90 ° coupler structures and a hybrid ring, made in a printed circuit and placed at the base of the antennas.

La figure 3 présente un exemple d'hélice 30 selon l'invention, sous sa forme développée. L'antenne HQI 30 comporte donc 4 brins rayonnants conducteurs 311 à 314 régulièrement espacés, imprimés sur un substrat 32 et de largeur égale à Wa. Les quatre brins 311 à 314 sont repliés sur eux mêmes à l'une de leur extrémité respectivement 361 à 364 en formant chacun un brin parasite respectivement 341 à 344 et connectés à l'autre extrémité aux lignes d'attaque du circuit d'alimentation 33.Figure 3 shows an example of a propeller 30 according to the invention, in its expanded form. The HQI antenna 30 thus comprises 4 regularly spaced conducting radiating strands 31 1 to 31 4 , printed on a substrate 32 and having a width equal to Wa. The four strands 31 1 to 31 4 are folded on themselves at one of their end respectively 36 1 to 36 4 , each forming a parasitic strand respectively 34 1 to 34 4 and connected at the other end to the lines of attack of the supply circuit 33.

Les brins parasites 341 à 344 ont une largeur Wbr inférieure à la largeur, Wa, des brins rayonnants afin de garantir un fonctionnement en large bande de l'antenne. Les brins parasites 341 à 344 sont connectés à la masse 35 à l'extrémité opposée à l'extrémité respectivement 361 à 364. Dans le mode de réalisation décrit en regard de la figure 3, la largeur, Wbr, des brins parasites et la largeur, Wa, des brins rayonnants sont constantes.The parasitic strands 34 1 to 34 4 have a width W br less than the width, W a , radiating strands to ensure broadband operation of the antenna. The parasitic strands 34 1 to 34 4 are connected to the ground 35 at the end opposite the end respectively 36 1 to 36 4 . In the embodiment described with reference to FIG. 3, the width, W br , parasitic strands and the width, W a , radiating strands are constant.

L'antenne 30 est ensuite enroulée sur un support cylindrique, comme illustrée sur la figure 4, qui présente une vue de face de l'antenne enroulée sur son support cylindrique.The antenna 30 is then wound on a cylindrical support, as shown in Figure 4, which has a front view of the antenna wound on its cylindrical support.

On décrit maintenant en détail un mode de réalisation particulier de l'invention. Bien entendu, il ne s'agit que d'un simple exemple, et de nombreuses variantes et adaptations sont possibles, en fonction des besoins et des applications.A particular embodiment of the invention will now be described in detail. Of course, it is only a simple example, and many variations and adaptations are possible, depending on the needs and applications.

L'antenne réalisée et illustrée en regard des figures 3 et 4 présente les caractéristiques suivantes :

  • Longueur des brins : 0,83λ, où λ représente la longueur d'onde correspondant à la fréquence moyenne de la bande d'émission (cette longueur ayant été choisie pour optimiser l'ouverture de l'antenne) ;
  • Diamètre : 0,18λ ;
  • Distance d : 9 mm ;
  • Largeur Wbr : 1,95 mm
  • Rapport des largeurs de brin Wa/Wbr : 8.
  • Angle d'enroulement, α : 50°.
The antenna produced and illustrated with reference to FIGS. 3 and 4 has the following characteristics:
  • Length of the strands: 0.83λ, where λ represents the wavelength corresponding to the average frequency of the emission band (this length having been chosen to optimize the opening of the antenna);
  • Diameter: 0.18λ;
  • Distance d : 9 mm;
  • Width W br : 1.95 mm
  • Width width ratio W a / W br : 8.
  • Winding angle, α: 50 °.

Généralement, la bande de l'antenne s'élargit lorsque la distance d augmente. Préférentiellement, le brin parasite est donc proche du brin rayonnant voisin.Generally, the antenna band widens as the distance d increases. Preferably, the parasitic strand is therefore close to the neighboring radiating strand.

D'une manière générale, il existe un optimum de bande passante en fonction de la distance entre un brin parasite et le brin rayonnant associé.In general, there is an optimum bandwidth depending on the distance between a parasitic strand and the associated radiating strand.

La figure 5 permet de visualiser le ROS 52 mesuré en fonction de la fréquence 50 (exprimé en GHz sur la figure) mesurée à l'entrée d'un brin rayonnant pour l'antenne 30 illustrée en regard des figures 3 et 4, les autres étant chargés sous 50Ω.FIG. 5 shows the measured ROS 52 as a function of the frequency 50 (expressed in GHz in the figure) measured at the input of a radiating strand for the antenna 30 illustrated with reference to FIGS. 3 and 4, the others being charged under 50Ω.

Les antennes sont mesurées à la fréquence centrale F1 égale à 1.5 GHz.The antennas are measured at center frequency F1 equal to 1.5 GHz.

On constate que pour l'antenne HQI à brin replié selon l'invention, on obtient une adaptation de l'antenne HQI inférieure à -10dB sur l'intervalle allant de 1,27GHz à 1,65 GHz, soit une bande passante qui atteint 26%. Ainsi, l'antenne HQI présente une augmentation significative de la bande passante. On passe en effet d'une bande passante de l'ordre 6 à 8 % pour une antenne HQI conventionnelle à une bande passante de l'ordre de 26% pour une antenne telle qu'illustrée en regard des figures 3 et 4.It can be seen that for the folded-over HQI antenna according to the invention, an adaptation of the HQI antenna of less than -10 dB is obtained over the interval from 1.27 GHz to 1.65 GHz, ie a bandwidth that reaches 26%. Thus, the HQI antenna has a significant increase in bandwidth. We go into effect of a bandwidth of about 6 to 8% for a conventional HQI antenna at a bandwidth of about 26% for an antenna as illustrated with reference to Figures 3 and 4.

Ainsi, l'antenne hélice quadrifilaire imprimée repliée dont chaque brin parasite est relié à la masse permet l'émission et/ou la réception dans une large bande passante ou dans deux sous-bandes différentes possédant chacune une large bande passante.Thus, the folded printed quadrifilar helix antenna which each parasitic strand is connected to ground allows the transmission and / or reception in a wide bandwidth or in two different sub-bands each having a wide bandwidth.

La technique de l'invention donne donc une augmentation non négligeable de la bande passante. On obtient ainsi une antenne hélice quadrilifaire imprimée fonctionnant dans une large bande passante et/ou dans deux sous-bandes différentes ayant chacune une large bande passante, et dont la hauteur est réduite. L'antenne hélice quadrifilaire imprimée repliée avec des brins parasites reliés à la masse permet donc une augmentation de la bande passante de l'antenne sans réduction des longueurs de brins.The technique of the invention therefore gives a significant increase in the bandwidth. This produces a printed quadrilateral helix antenna operating in a wide bandwidth and / or in two different sub-bands each having a wide bandwidth, and whose height is reduced. The folded quadrifilar helix antenna folded with parasitic strands connected to the ground therefore allows an increase in the bandwidth of the antenna without reducing the lengths of strands.

La figure 6 est une abaque de Smith représentant l'impédance 60 d'entrée d'une antenne selon l'invention normalisée à 50 Ohms.Figure 6 is a Smith chart representing the input impedance 60 of an antenna according to the invention standardized at 50 Ohms.

Une boucle 61 sur la courbe 60 est issue du couplage et donne la large bande puisque présente à l'intérieur d'un cercle 62 correspondant à un ROS inférieur ou égal à 2.A loop 61 on the curve 60 is derived from the coupling and gives the wide band since present inside a circle 62 corresponding to a ROS less than or equal to 2.

La figure 7a présente un exemple d'hélice 70 selon une variante de l'invention, sous sa forme développée. L'antenne HQI 70 comporte donc 4 brins rayonnants conducteurs 711 à 714 régulièrement espacés, imprimés sur une première face du substrat 72 et de largeur égale à Wa. Les quatre brins 711 à 714 sont connectés à l'une de leur extrémité aux lignes d'attaque du circuit d'alimentation 73.FIG. 7a shows an example of a helix 70 according to a variant of the invention, in its developed form. The HQI antenna 70 thus comprises four regularly spaced conductive radiating strands 71 1 to 71 4 printed on a first face of the substrate 72 and of width equal to W a . The four strands 71 1 to 71 4 are connected at one end to the leading lines of the supply circuit 73.

Des brins parasites 741 à 744 (représentés en pointillés) sont imprimés parallèlement aux brins rayonnants sur une seconde face du substrat 72 opposée à la première face. Les brins parasites 741 à 744 sont connectés à la masse 75 à l'une de leur extrémité respectivement 711 à 714.Strands 74 1 to 74 4 (shown in dashed lines) are printed parallel to the radiating strands on a second face of the substrate 72 opposite the first face. The parasitic strands 74 1 to 74 4 are connected to the ground 75 at one of their end respectively 71 1 to 71 4 .

Chacun des brins parasites 741 à 744 est couplé par son extrémité respectivement 751 à 754 non reliée à la masse 75, à l'extrémité non reliée à l'alimentation du brin respectivement 711 à 714 auquel il est associé. Les brins parasites 741 à 744 ont une largeur Wbr inférieure ou égale et, préférentiellement très inférieure (dans un rapport Wbr/Wa inférieur à 0,15), à la largeur, Wa, des brins rayonnants afin de garantir un fonctionnement en large bande de l'antenne. Dans le mode de réalisation décrit en regard des figures 7a et 7b, la largeur, Wbr, des brins parasites et la largeur, Wa, des brins rayonnants sont constantes.Each of parasitic strands 74 1 to 74 4 is coupled by its end 75 1 to 75 4, respectively, not connected to ground 75, at the end not connected to the supply of strand respectively 71 1 to 71 4 to which it is associated. The parasitic strands 74 1 to 74 4 have a width W br less than or equal to and preferably much lower (in a ratio W br / W a less than 0.15), the width W a , radiating strands in order to guarantee a broadband operation of the antenna. In the embodiment described with reference to FIGS. 7a and 7b, the width, W br, parasitic strands and the width, W a , radiating strands are constant.

Ici, la distance séparant un brin parasite et le brin rayonnant associé n'est pas limitée par la distance séparant deux brins rayonnants. Ainsi, la distance entre un brin parasite et le brin rayonnant peut être supérieure à la distance séparant deux brins rayonnants. Le couplage entre un brin parasite et le brin rayonnant associé et donc la bande passante peuvent être alors améliorés. On possède alors plus de possibilités dans la recherche de couplage optimum.Here, the distance separating a parasitic strand and the associated radiating strand is not limited by the distance separating two radiating strands. Thus, the distance between a parasitic strand and the radiating strand may be greater than the distance separating two radiating strands. The coupling between a parasitic strand and the associated radiating strand and therefore the bandwidth can then be improved. We then have more possibilities in the search for optimum coupling.

La figure 7b illustre en détail l'extrémité 751 du brin rayonnant 711 couplée au brin parasite 741. D'une manière générale, chacun des brins parasites et le brin rayonnant associé se chevauchent de part et d'autre du substrat 72 sur une distance E comprise entre 0 et la distance d séparant le brin parasite du brin rayonnant associé.FIG. 7b illustrates in detail the end 751 of the radiating strand 711 coupled to the parasitic strand 741. In general, each of the parasitic strands and the associated radiating strand overlap on both sides of the substrate 72 over a distance E between 0 and the distance d separating the parasitic strand from the associated radiating strand.

Les autres caractéristiques de l'antenne 70 (enroulement autour d'un support cylindrique, dimensions des brins et de l'antenne...) étant similaires à celle de l'antenne 30 des figures 3 et 4, elles ne seront pas décrites davantage.The other characteristics of the antenna 70 (winding around a cylindrical support, dimensions of the strands and the antenna, etc.) being similar to that of the antenna 30 of FIGS. 3 and 4, will not be described further. .

La figure 8 présente un exemple d'antenne 80 selon une variante de l'invention selon laquelle des brins rayonnants 811, à 814 sont de largeur variable. Chacun des brins rayonnants 811, à 814 est relié par l'une de ses extrémités à un brin parasite 841 à 844.FIG. 8 shows an example of an antenna 80 according to a variant of the invention according to which radiating strands 81 1 to 81 4 are of variable width. Each of the radiating strands 81 1 to 81 4 is connected at one of its ends to a parasitic strand 84 1 to 84 4 .

Ce mode de réalisation a notamment pour objectif d'obtenir une antenne HQI 80 permettant d'élargir encore plus la bande passante et/ou de permettre une meilleure adaptation de l'antenne 80 (la variation de la largeur de la bande étant un paramètre supplémentaire utilisable pour l'adaptation). Ceci est obtenu en faisant varier la largeur des brins rayonnants le long de l'hélice. Ainsi, les extrémités des brins rayonnants ont respectivement une largeur Wa1 et Wa2 différente. La variation de la largeur peut être :

  • régulière suivant une loi linéaire, exponentielle, double exponentielle, en escalier...ou
  • non régulière.
This embodiment has the particular objective of obtaining an HQI antenna 80 making it possible to further widen the bandwidth and / or to allow a better adaptation of the antenna 80 (the variation of the bandwidth being an additional parameter usable for adaptation). This is obtained in varying the width of the radiating strands along the helix. Thus, the ends of the radiating strands respectively have a width W a1 and W a2 different. The variation of the width can be:
  • regular following a linear law, exponential, double exponential, staircase ... or
  • not regular.

Préférentiellement, la largeur des brins parasites est constante et chacun des brins parasites est parallèle à une ligne médiane longitudinale du brin rayonnant associé (illustrée, par exemple, par la ligne 87 correspondant au brin 811).Preferably, the width of the parasitic strands is constant and each of the parasitic strands is parallel to a longitudinal median line of the associated radiating strand (illustrated, for example, by the line 87 corresponding to the strand 81 1 ).

A titre illustratif, chacun des brins rayonnant de l'antenne 80 présente une largeur minimale Wa1 égale à 2mm et une largeur maximale Wa2 égale à 16 mm.As an illustration, each of the radiating strands of the antenna 80 has a minimum width W a1 equal to 2 mm and a maximum width W a2 equal to 16 mm.

A l'exception de la largeur des brins rayonnants, les caractéristiques de l'antenne 80 étant similaires à celles de l'antenne 30 illustrée en regard des figures 3 et 4, elles ne seront pas décrites davantage.With the exception of the width of the radiating strands, the characteristics of the antenna 80 being similar to those of the antenna 30 illustrated with reference to FIGS. 3 and 4, they will not be described further.

Selon une variante de l'invention non illustrée, les brins parasites d'une antenne hélicoïdale sont couplés et non reliés directement à des brins rayonnants de largeur variable, similaires aux brins 811 à 814 de l'antenne 80 (selon un couplage similaire à celui des brins rayonnants et parasites de l'antenne 70).According to a variant of the invention not illustrated, the parasitic strands of a helical antenna are coupled and not directly connected to radiating strands of variable width, similar to the strands 81 1 to 81 4 of the antenna 80 (according to a similar coupling to that of the radiating and parasitic strands of the antenna 70).

Selon une autre variante de l'invention, la largeur des brins parasites est variable, les lignes médianes longitudinales de chacun des brins parasites et du brin rayonnant associé sont parallèles.According to another variant of the invention, the width of the parasitic strands is variable, the longitudinal median lines of each of the parasitic strands and the associated radiating strand are parallel.

Selon encore une autre variante non représentée, les brins parasites sont parallèles à l'un des cotés des brins rayonnants. Un brin parasite parallèle à un brin rayonnant adjacent permet, notamment, d'éloigner ce brin parasite du brin rayonnant associé tout en le rapprochant du brin adjacent augmentant ainsi l'effet capacitif et la bande passante de l'antenne.According to yet another variant not shown, the parasitic strands are parallel to one of the sides of the radiating strands. A parasitic strand parallel to an adjacent radiating strand makes it possible, in particular, to move this parasitic strand away from the associated radiating strand while bringing it closer to the adjacent strand, thereby increasing the capacitive effect and the bandwidth of the antenna.

D'une manière générale, les brins parasites et les brins rayonnants sont reliés par un seul point de liaison.In general, the parasitic strands and the radiating strands are connected by a single point of connection.

La figure 9a montre un exemple d'antenne 90 selon une autre variante de l'invention présentant des brins rayonnants 911 à 914 formant une ligne brisée.FIG. 9a shows an example of antenna 90 according to another variant of the invention having radiating strands 91 1 to 91 4 forming a broken line.

Chacun des brins rayonnants 911 à 914 est reliés par l'une de ses extrémités à un brin parasite 941 à 944.Each of the radiating strands 91 1 to 91 4 is connected at one of its ends to a parasitic strand 94 1 to 94 4 .

Chaque brin rayonnant 911 à 914 (ou au moins certains) de l'antenne HQI est décomposé en un nombre limité de segments. D'après les expressions mathématiques liant les paramètres géométriques d'une antenne hélice, on constate qu'une modification de l'angle d'enroulement influe sur le pas de l'antenne, donc sur la longueur axiale.Each radiating strand 91 1 to 91 4 (or at least some) of the HQI antenna is decomposed into a limited number of segments. According to the mathematical expressions linking the geometrical parameters of a helical antenna, one observes that a modification of the winding angle influences the pitch of the antenna, thus the axial length.

Ainsi il est possible de donner un angle d'enroulement différent pour chaque segment. La hauteur peut ainsi s'en trouver réduite. Instaurer des angles d'enroulement différents peut être assimilé à un changement du pas de l'antenne.Thus it is possible to give a different winding angle for each segment. The height can thus be reduced. Establishing different winding angles can be likened to a change in the pitch of the antenna.

Cependant, l'angle d'enroulement α est aussi un paramètre influant sur le diagramme de rayonnement d'une antenne HQI (angle d'ouverture à 3dB, rapport d'ellipticité). C'est pourquoi, pour choisir les différents angles α adéquats, un programme d'optimisation globale tel que le recuit simulé ou l'algorithme génétique peut être utilisé.However, the winding angle α is also a parameter influencing the radiation pattern of an HQI antenna (opening angle at 3dB, ellipticity ratio). Therefore, to choose the different angles α adequate, a global optimization program such as simulated annealing or the genetic algorithm can be used.

La synthèse est effectuée sur les diagrammes de rayonnement en polarisation principale et croisée en introduisant un gabarit défini par les niveaux d'amplitude et les angles d'ouverture -3dB voulus.The synthesis is performed on the main and crossed polarization radiation diagrams by introducing a template defined by the desired amplitude levels and aperture angles -3dB.

La mise en place de ce gabarit permet de contrôler parfaitement les angles d'ouverture à -3dB, ainsi que la réjection de la polarisation inverse donc le rapport d'ellipticité. Les variables à optimiser sont les différents angles d'enroulement des brins de l'antenne HQI. L'algorithme donnera les angles αi optimum.The installation of this template makes it possible to perfectly control the angles of opening at -3 dB, as well as the rejection of the inverse polarization and therefore the ellipticity ratio. The variables to be optimized are the different winding angles of the strands of the HQI antenna. The algorithm will give the angles α i optimum.

Chacune des brins rayonnant 911, à 914 de l'antenne 90 présenté en regard de la figure 9a est divisé par exemple en huit segments de longueur, L, identique. Les angles d'enroulement correspondant à chacun des huit segments des brins rayonnant de l'antenne 90 sont les suivants :

  • α1 = 30° ;
  • α2 = 33° ;
  • α3 = 55° ;
  • α4 = 34° ;
  • α5 = 65° ;
  • α6 = 68° ;
  • α7 = 54° ; et
  • α8 = 33°.
Each of the radiating strands 91 1 , 91 4 of the antenna 90 presented with reference to Figure 9a is divided for example into eight segments of length, L , identical. The winding angles corresponding to each of the eight segments of the strands radiating from the antenna 90 are as follows:
  • α 1 = 30 °;
  • α 2 = 33 °;
  • α 3 = 55 °;
  • α 4 = 34 °;
  • α 5 = 65 °;
  • α 6 = 68 °;
  • α 7 = 54 °; and
  • α 8 = 33 °.

Les brins rayonnant 911 et parasite 941 et en particulier les segments qui composent le brin rayonnant 911 sont illustrés plus en détail en regard de la figure 9b.The radiating strands 91 1 and parasite 94 1 and in particular the segments that make up the radiating strand 91 1 are illustrated in more detail with respect to FIG. 9b.

On obtient ainsi une antenne HQI 90 à pas variable aléatoire avec des dimensions réduites.An HQI 90 antenna with random variable pitch is thus obtained with reduced dimensions.

Bien entendu, en fonction des besoins des contraintes différentes peuvent être prises en compte lors de l'optimisation.Of course, depending on the needs of different constraints can be taken into account during optimization.

Ainsi une modification des angles d'enroulement permet d'une part de diminuer la longueur axiale de l'antenne HQI et d'autre part d'obtenir le rapport d'ellipticité et la couverture souhaités.Thus, a modification of the winding angles makes it possible on the one hand to reduce the axial length of the HQI antenna and on the other hand to obtain the desired ellipticity ratio and coverage.

Selon la figure 9b, le brin parasite 941 est parallèle à une tangente 97 intérieure (c'est-à-dire située entre le brin rayonnant 911 et le brin parasite associé941) du brin rayonnant 911.According to FIG. 9b, the parasitic strand 94 1 is parallel to an inner tangent 97 (i.e. between the radiating strand 91 1 and the associated parasitic strand 94 1 ) of the radiating strand 91 1 .

Selon une variante non illustrée, un ou plusieurs brins parasites sont parallèles à une tangente extérieure (c'est-à-dire située du coté opposé au brin parasite) du brin rayonnant associé (ce qui permet de rapprocher le brin parasite d'un brin adjacent voisin) ou à une ligne médiane du brin rayonnant associé.According to a non-illustrated variant, one or more parasitic strands are parallel to an outer tangent (that is to say located on the opposite side to the parasitic strand) of the associated radiating strand (which makes it possible to bring the strand strand closer to a strand adjacent neighbor) or at a median line of the associated radiating strand.

Selon une autre variante non illustrée, un ou plusieurs brins parasites forment une ligne brisée. Préférentiellement, chacun de ces brins parasites comporte le même nombre de segments que le brin rayonnant associé et chacun des segments du brin parasite a la même longueur et est parallèle à un segment correspondant sur le brin rayonnant associé (ainsi, outre une largeur différente, le brin parasite et le brin rayonnant associé ont la même forme), ce qui permet de positionner un brin parasite très près d'un brin adjacent rayonnant.According to another variant not illustrated, one or more parasitic strands form a broken line. Preferably, each of these parasitic strands has the same number of segments as the associated radiating strand and each of the parasitic strand segments has the same length and is parallel to a corresponding segment on the associated radiating strand (thus, besides a different width, the parasitic strand and the associated radiating strand have the same shape), which makes it possible to position a parasitic strand very close to an adjacent radiating strand.

Selon encore une autre variante de l'invention non illustrée, les brins parasites d'une antenne hélicoïdale sont reliés par couplage (et non directement) à des brins rayonnants formant une ligne brisée de façon similaire à la liaison par couplage présentée en regard des figures 7a et 7b.According to yet another variant of the invention that is not illustrated, the parasitic strands of a helical antenna are connected by coupling (and not directly) to radiating strands forming a broken line in a manner similar to the coupling connection presented with reference to FIGS. 7a and 7b.

De nombreuses variantes des modes de réalisation illustrés en regard des figures 3 à 9 sont envisageables.Numerous variants of the embodiments illustrated with reference to FIGS. 3 to 9 are conceivable.

En particulier, il convient de rappeler que la largeur des brins parasites peut prendre une valeur quelconque inférieure à celle d'un brin rayonnant associé et préférentiellement de l'ordre du huitième de celle d'un brin rayonnant associé.In particular, it should be remembered that the width of the parasitic strands may take any value less than that of an associated radiating strand and preferably of the order of one-eighth that of an associated radiating strand.

Par ailleurs, bien que l'invention peut s'appliquer à tout type d'antenne en hélice, et non uniquement aux antennes quadrilifaires.Moreover, although the invention can be applied to any type of helical antenna, and not only to quadrilateral antennas.

On peut également envisager que les brins ne présentent pas tous des dimensions identiques.It can also be envisaged that the strands do not all have identical dimensions.

Selon le mode de réalisation décrit, l'antenne est imprimée à plat, ensuite enroulée sur un support pour former l'antenne. Selon un autre mode de réalisation encore plus rapide, le substrat destiné à recevoir les éléments imprimés peut être réalisé directement dans sa forme cylindrique définitive. Dans ce cas, l'impression des brins et de la structure d'alimentation est effectuée directement sur le cylindre.According to the embodiment described, the antenna is printed flat, then wound on a support to form the antenna. According to another even faster embodiment, the substrate for receiving the printed elements can be made directly in its final cylindrical form. In this case, the printing of the strands and the feed structure is performed directly on the cylinder.

Par ailleurs, il est à noter que, bien qu'elle soit utilisable à l'unité, l'antenne de l'invention se prête également à la réalisation de réseaux d'antennes.Furthermore, it should be noted that, although it can be used individually, the antenna of the invention also lends itself to the realization of antenna arrays.

Il est également possible de montrer coaxialement et concentriquement deux (ou plus) antennes de ce type.It is also possible to show coaxially and concentrically two (or more) antennas of this type.

Enfin, la technique de l'invention est compatible avec des techniques visant à réduire la taille de l'antenne, telle que notamment celle proposée dans la demande de brevet dans le document de brevet FR-0011830 , au nom de France Telecom (antenne hélicoïdale à pas variable) ou à augmenter la largeur de bande, par exemple, selon une technique proposée dans le document de brevet FR-0011843 , au nom de France Telecom (antenne hélicoïdale à brins de largeur variable). Dans ces différents cas, la présence de pas variable et/ou la variation de largeur peut être appliquée sur tous les brins, ou sélectivement sur certains d'entre eux.Finally, the technique of the invention is compatible with techniques for reducing the size of the antenna, such as in particular that proposed in the patent application in the patent document. FR-0011830 , on behalf of France Telecom (helical antenna with variable pitch) or to increase the bandwidth, for example, according to a technique proposed in the patent document FR-0011843 , on behalf of France Telecom (helical antenna with wide strands variable). In these different cases, the presence of variable pitch and / or the variation of width can be applied on all the strands, or selectively on some of them.

Claims (14)

  1. Helical antenna (30, 70, 80, 90) including at least one helix formed by at least two radiating wires (31, 71, 81, 91), each of them being connected by coupling to an associated parasitic wire (34, 74, 84, 94) by one first end,
    said radiating wires and parasitic wires (34, 74, 84, 94) being parallel and having the same length,
    characterised in that said parasitic wires (34, 74, 84, 94) are narrower than or equal in width to said radiating wires,
    and in that each of said parasitic wires is farther in a direction perpendicular to the axis of said wires from said associated radiating wire than from at least one of said other radiating wires.
  2. Helical antenna according to claim 1,
    characterised in that the ratio between the width of each of said parasitic wires and the width of said associated radiating wire is less than or equal to 0.15.
  3. Helical antenna according to either of claims 1 and 2, characterised in that said radiating wires and said parasitic wires are printed on a substrate (32, 72, 82, 92).
  4. Helical antenna according to any one of claims 1 to 3, characterised in that each of said parasitic wires is connected to the ground (35, 75, 85, 95).
  5. Helical antenna according to any one of claims 1 to 4, characterised in that each of said parasitic wire (74) is connected by a conductive connection (36, 86, 96) to one of said radiating wire (31, 71, 81, 91).
  6. Helical antenna according to any one of claims 1 to 4, characterised in that each of said parasitic wire (74) is connected by an electromagnetic connection (36, 86, 96) to one of said radiating wire (31, 71, 81, 91).
  7. Helical antenna according to any one of claims 3 to 6, characterised in that said radiating wires are printed on a first surface of a substrate and in that said parasitic wires are printed on a second surface of said substrate.
  8. Helical antenna according to claim 7,
    characterised in that at least one parasitic wire and one radiating wire adjacent to said radiating wire with which said parasitic wire is associated overlap each other.
  9. Helical antenna according to any one of claims 8 to 10, characterised in that the second end of said radiating wires is connected to a feedline of a power supply circuit (33, 73, 83, 93).
  10. Helical antenna according to any one of claims 1 to 9, characterised in that at least one of said helices is a quadrifilar helix, including four wires.
  11. Helical antenna according to any one of claims 1 to 10, characterised in that said radiating wires forming a helix are all the same size and in that said parasitic wires are all the same size.
  12. Helical antenna (90) according to any one of claims 1 to 11, characterised in that at least one of said radiating and/or parasitic wires is formed by at least two segments, in which the angles of coil of at least two of said segments are different.
  13. Helical antenna (80) according to any one of claims 1 to 12, characterised in that at least one of said radiating and/or parasitic wires has a variable width, varying regularly and monotonously between a maximum and a minimum width.
  14. Helical antenna according to any one of claims 1 to 13, characterised in that said radiating wires have a length substantially different from a multiple of the wavelength corresponding to the mean frequency of the transmission band of said antenna, divided by 4.
EP03797356A 2002-09-20 2003-09-19 Broadband helical antenna Expired - Lifetime EP1540768B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR0211696 2002-09-20
FR0211696A FR2844923B1 (en) 2002-09-20 2002-09-20 BROADBAND HELICOIDAL ANTENNA
PCT/FR2003/002774 WO2004027930A1 (en) 2002-09-20 2003-09-19 Broadband helical antenna

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EP1540768A1 EP1540768A1 (en) 2005-06-15
EP1540768B1 true EP1540768B1 (en) 2008-01-16

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AT (1) ATE384346T1 (en)
AU (1) AU2003298989A1 (en)
DE (1) DE60318725T2 (en)
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Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0700276D0 (en) * 2007-01-08 2007-02-14 Sarantel Ltd A dielectrically-loaded antenna
FR2916581B1 (en) * 2007-05-21 2009-08-28 Cnes Epic PROPELLER TYPE ANTENNA.
US8089421B2 (en) * 2008-01-08 2012-01-03 Sarantel Limited Dielectrically loaded antenna
GB0904307D0 (en) 2009-03-12 2009-04-22 Sarantel Ltd A dielectrically-loaded antenna
US10129929B2 (en) * 2011-07-24 2018-11-13 Ethertronics, Inc. Antennas configured for self-learning algorithms and related methods
US9614293B2 (en) 2012-10-17 2017-04-04 The Mitre Corporation Multi-band helical antenna system
US9502767B2 (en) * 2013-11-22 2016-11-22 Topcon Positioning Systems, Inc. Compact antenna system with reduced multipath reception
US10637137B2 (en) * 2015-04-09 2020-04-28 Topcon Positioning Systems, Inc. Broadband helical antenna with cutoff pattern
US10194220B2 (en) * 2017-01-05 2019-01-29 Pulse Finland Oy Antenna apparatus that utilizes a utility line and methods of manufacturing and use
US11183763B2 (en) 2019-12-31 2021-11-23 Atlanta RFtech LLC Low profile dual-band quadrifilar antenna
CN112864594A (en) * 2021-01-06 2021-05-28 昆山睿翔讯通通信技术有限公司 Millimeter wave antenna based on sub-6G low frequency band
US11437728B1 (en) 2021-03-26 2022-09-06 Atlanta RFtech LLC Multi-band quadrifilar helix slot antenna

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2654554B1 (en) 1989-11-10 1992-07-31 France Etat ANTENNA IN PROPELLER, QUADRIFILAIRE, RESONANT BICOUCHE.
AU3677795A (en) * 1995-04-26 1996-11-18 Westinghouse Electric Corporation Helical antenna having a parasitic element and a method of u sing the same
US5838285A (en) * 1995-12-05 1998-11-17 Motorola, Inc. Wide beamwidth antenna system and method for making the same
FR2746547B1 (en) 1996-03-19 1998-06-19 France Telecom PROPELLER ANTENNA WITH INTEGRATED BROADBAND SUPPLY, AND MANUFACTURING METHODS THEREOF
US5990847A (en) * 1996-04-30 1999-11-23 Qualcomm Incorporated Coupled multi-segment helical antenna
US5986619A (en) * 1996-05-07 1999-11-16 Leo One Ip, L.L.C. Multi-band concentric helical antenna
US6278414B1 (en) * 1996-07-31 2001-08-21 Qualcomm Inc. Bent-segment helical antenna
US6160516A (en) * 1999-10-07 2000-12-12 Motorola, Inc. Dual pattern antenna for portable communications devices
US6229499B1 (en) * 1999-11-05 2001-05-08 Xm Satellite Radio, Inc. Folded helix antenna design
CA2358875A1 (en) * 1999-12-15 2001-06-21 Mitsubishi Denki Kabushiki Kaisha Antenna device
FR2814285A1 (en) 2000-09-15 2002-03-22 France Telecom VARIABLE STEP HELICOID ANTENNA, AND CORRESPONDING METHOD
FR2814286B1 (en) 2000-09-15 2004-05-28 France Telecom VARIABLE WIDTH PROPELLER ANTENNA

Also Published As

Publication number Publication date
DE60318725T2 (en) 2009-01-02
US7525508B2 (en) 2009-04-28
EP1540768A1 (en) 2005-06-15
DE60318725D1 (en) 2008-03-06
WO2004027930A1 (en) 2004-04-01
US20060125712A1 (en) 2006-06-15
FR2844923A1 (en) 2004-03-26
ATE384346T1 (en) 2008-02-15
AU2003298989A1 (en) 2004-04-08
FR2844923B1 (en) 2006-06-16

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