WO2017025674A1 - Surface wave antenna system - Google Patents

Surface wave antenna system Download PDF

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Publication number
WO2017025674A1
WO2017025674A1 PCT/FR2016/051916 FR2016051916W WO2017025674A1 WO 2017025674 A1 WO2017025674 A1 WO 2017025674A1 FR 2016051916 W FR2016051916 W FR 2016051916W WO 2017025674 A1 WO2017025674 A1 WO 2017025674A1
Authority
WO
WIPO (PCT)
Prior art keywords
antenna
antenna system
cover
radiation
wired
Prior art date
Application number
PCT/FR2016/051916
Other languages
French (fr)
Inventor
Mathilde Bellec
Sébastien PALUD
Pierre-Yves Jezequel
Franck Colombel
Stéphane AVRILLON
Original Assignee
Tdf
Universite De Rennes 1
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tdf, Universite De Rennes 1 filed Critical Tdf
Priority to ES16753413T priority Critical patent/ES2958409T3/en
Priority to EP16753413.0A priority patent/EP3335268B1/en
Publication of WO2017025674A1 publication Critical patent/WO2017025674A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H01Q9/32—Vertical arrangement of element
    • H01Q9/36—Vertical arrangement of element with top loading
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/04—Adaptation for subterranean or subaqueous use
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/44—Details of, or arrangements associated with, antennas using equipment having another main function to serve additionally as an antenna, e.g. means for giving an antenna an aesthetic aspect
    • H01Q1/46—Electric supply lines or communication lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/10—Resonant antennas
    • H01Q5/15—Resonant antennas for operation of centre-fed antennas comprising one or more collinear, substantially straight or elongated active elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
    • H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point
    • H01Q5/364—Creating multiple current paths
    • H01Q5/371—Branching current paths
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/44—Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions
    • H01Q9/46—Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions with rigid elements diverging from single point

Definitions

  • the invention relates to an antennal system.
  • the invention relates to an antenna system with vertical and / or elliptical polarization adapted to emit and / or receive surface waves in a wide frequency band including in particular all or part of the low, medium and high frequencies between 30 kHz approximately 30 MHz, consisting of LF, MF and HF.
  • Antennas using only a surface wave as propagation vector are very few.
  • Current surface wave systems use whip or biconical antennas that are poorly suited for radar applications.
  • space wave field also called ionospheric radiation
  • the French patent application F 2965978 filed by the applicant, proposes a solution to significantly reduce the vertical size of the antenna, thus reducing implementation costs and improving the discretion of the antenna .
  • the antenna provides improved surface wave propagation and decreased ionospheric radiation. Nevertheless, the ionospheric radiation remains important, especially for angles between ⁇ [20 °; 80 °] around the normal to the ground plane on which the antenna is placed. This remaining ionospheric radiation can, in certain frequency bands, generate attenuation phenomena (fading in English), especially when the surface waves and the space waves interfere, at the surface of the Earth, after propagation in different environments and paths.
  • the invention aims to overcome at least some of the disadvantages of known antennas.
  • the invention aims to provide, in at least one embodiment of the invention, an antenna system whose preferential radiation is a surface wave radiation.
  • the invention also aims to provide, in at least one embodiment, an antennal system whose ionospheric radiation is reduced.
  • the invention also aims to provide, in at least one embodiment of the invention, a simple antenna system to achieve.
  • the invention also aims to provide, in at least one embodiment, a discrete antennal system and whose vertical footprint is low.
  • the invention also aims to provide, in at least one embodiment, an antenna system whose bandwidth can be easily modified.
  • an antenna system with surface waves comprising:
  • At least one vertical electrically short antenna with vertical or elliptical polarization and adapted to emit / receive radiation in at least one frequency band centered on a central frequency f 0 associated with a central wavelength ⁇ 0 , said antenna being connected to a conductive medium having a substantially horizontal surface,
  • At least one wired cover of length greater than or equal to 0.8 ⁇ 0 electrically connected to at least one antenna at the center of the hood, and adapted to radiate at least the central frequency f 0 of the antenna.
  • the term "electrically short antenna” in the vertical plane means an antenna emitting radiation in a preferential wavelength called central wavelength ⁇ 0 , and whose vertical space is less than a quarter of the central wavelength. If the antenna transmits on a frequency band, the central wavelength corresponds to the wavelength associated with the center frequency of the frequency band.
  • the antenna is for example an antenna as described in the French patent application FR2965978, a whip antenna, a PIFA type antenna (for Planar Inverted F-Shaped Antenna in English), M-shaped antenna, etc.
  • An antennal system therefore allows preferential radiation in surface waves, as well as the reduction of the ionospheric radiation of an antenna through the use of one or more wired hoods, so as to emit only surface waves.
  • the wired hoods are electrically connected to the antenna, so that a power supply of the antenna also feeds the wired hoods.
  • the wire hoods radiate at the center frequency f 0 and allow the modification of the antenna radiation pattern so as to reduce the ionospheric radiation of the antennal system.
  • the wire covers are formed of a wire or a metal tube of small section.
  • the vertical congestion of the antenna system is between 0.05 ⁇ 0 and 0.3 ⁇ 0 .
  • the antennal system is therefore discreet. In addition, it is less sensitive to wind, blast, lightning, earthquakes, etc.
  • the length of the wire cover is less than or equal to 2 ⁇ 0 .
  • said at least one antenna is configured to emit / receive directional radiation in a radiation direction, and at least one wire cover extends in a main direction substantially parallel to the radiation direction.
  • the ionospheric radiation of the antenna system is further reduced in the direction of radiation of the antenna when this one is a directional antenna.
  • At least one wire cover extends in a direction forming an angle of between -10 ° and 10 ° with the surface of the conductive medium.
  • the wired cover extends in a direction substantially parallel to the surface of the conductive medium.
  • substantially parallel means an angle between the direction of each cap and the surface of the conductive medium between -5 ° and 5 °.
  • the wired cover can also be strictly parallel to the surface of the conductive medium.
  • the reduction of the ionospheric radiation and the directivity of the antenna are improved.
  • an antenna system comprises at least two wire hoods extending in major directions different from each other.
  • the presence of a plurality of wire hoods allows reduction of the enhanced ionospheric radiation in several azimuths.
  • the conductive medium comprises a ground plane to which each antenna is connected.
  • the ground plane makes it possible to improve the conductivity of the conducting medium if this conductivity is too low.
  • at least one wire cover comprises at least one localized element adapted to allow the resonance of said cover at a multitude of frequencies.
  • the localized elements which may be resistive, capacitive or inductive elements, make it possible to form on the cover (s) open circuits (or high impedance) or closed circuits according to the operating frequencies, forming as well as current traps.
  • the localized elements are thus adapted to obtain a multifrequency (i.e. multiple resonant) antenna system via said current traps.
  • the localized elements may also make it possible to reproduce the LC resonance of the hood with a reduced physical cover length but an equivalent electrical length.
  • the localized elements are thus adapted to modify the electrical length of the hood.
  • At least one wire cover comprises a plurality of wire elements connected to each other so as to form a surface cover or a volume cover.
  • the surface or volume covers allow to increase the bandwidth of the antennal system.
  • the surface or volume covers are adapted for use with broadband antennas.
  • the wire elements are, for example, strands made of tubes or metal wires.
  • the invention also relates to an antenna system characterized in combination by all or some of the characteristics mentioned above or below.
  • FIG. 1 is a schematic perspective view of an antenna system according to a first embodiment of the invention
  • FIG. 2 is a schematic perspective view of an antenna system according to a second embodiment of the invention.
  • FIG. 3 is a radiation diagram along the yOz plane of the antenna system according to the second embodiment of the invention.
  • FIG. 4 is a schematic perspective view of an antenna system according to a third embodiment of the invention.
  • FIG. 5 is a schematic perspective view of an antenna system according to a fourth embodiment of the invention.
  • FIG. 6 is a schematic perspective view of an antenna system according to a fifth embodiment of the invention.
  • FIG. 7 is a schematic perspective view of an antenna system according to a sixth embodiment of the invention.
  • FIG. 8 is a schematic perspective view of an antenna system according to a seventh embodiment of the invention.
  • FIG. 9 is a radiation diagram according to the yOz plane of the antenna system according to the seventh embodiment of the invention.
  • FIG. 10 is a schematic perspective view of an antenna system according to an eighth embodiment of the invention.
  • FIG. 11 is a schematic perspective view of an antenna system according to a ninth embodiment of the invention.
  • FIG. 12 is a schematic perspective view of an antenna system according to a tenth embodiment of the invention.
  • FIG. 13 is a schematic perspective view of an antenna system according to an eleventh embodiment of the invention.
  • Figure 14 is a schematic perspective view of an antenna system according to a twelfth embodiment of the invention.
  • Figure 1 shows schematically in perspective an antenna system according to a first embodiment of the invention.
  • the antenna system comprises an antenna 22, here an M-shaped antenna comprising a horizontal radiating element 24 connected to three vertical radiating elements 26a, 26b, 26c, themselves connected to a conductive medium 28.
  • the conductive medium 28 is represented by an electric ground symbol connected to the ground.
  • Conductive medium 28 is an imperfect conductive medium, for example soil (earth, sand, etc.) or water (sea, salt marsh, lake, etc.).
  • the antenna is fed at the level of the vertical radiating element 26b by a generator 29.
  • the antenna system further includes a wire hood 30 electrically connected to the antenna 22 at the center of the hood.
  • the wire hood 30 is connected to the antenna 22 at the center of the vertical radiating element 24.
  • the wired cap 30 is single stranded (i.e. it is composed of a single radiating wire), has a length greater than 0.8 ⁇ 0 and extends in a direction substantially parallel to the surface of the middle 28 conductor.
  • the conductive medium 28 has an electrical conductivity which varies according to its composition.
  • the sea, salt marshes or salt lakes have high electrical conductivity, and the earth and sand have low electrical conductivity.
  • the antenna system is completed by a ground plane, connected to the antenna 22, and buried below or on the surface of the conductive medium 28.
  • the ground plane may be formed of a plate, or a set of conductive wires forming a grid, etc.
  • the ground plane can take many forms, for example a circle, a polygon (regular or not), etc.
  • the ground plane extends below the entire antennal system, i.e., the projection of the antenna system onto the conductive medium 28 along the Oz axis is included in the surface occupied by the mass plan.
  • Figure 2 schematically shows in perspective an antenna system according to a second embodiment of the invention.
  • the antenna system comprises an antenna 22 as described in the French patent application FR2965978 filed by the applicant.
  • the antenna system includes a wire hood 30 electrically connected to the antenna 22 at the center of the hood.
  • the wired cap 30 is single strand, and is composed of two sub-strands 32a, 32b of equal lengths, connected to one of their ends and arranged in the same plane.
  • the two sub-strands are connected at an angle, due to the difference between the height h1 at which the sub-strands are connected and at the height of the other two ends of the sub-strands.
  • the angle is equal to 180 ° and therefore the sub-strands are aligned and the cover is parallel to the surface of the conductive medium 28, as the hood described above in the first mode of realization.
  • FIG. 3 represents a radiation pattern according to the yOz plane (referred to as the zenith radiation pattern) of the antenna system according to the second embodiment of the invention, in which the wired cap has a length of 0.8 ⁇ 0 , the height hl is equal to 0.06 ⁇ 0 , the height h2 is equal to 0.05 ⁇ 0 and the length L of the antenna is equal to 0.3 ⁇ 0 .
  • the radiation of the antennal system is therefore mainly surface-wave radiation, and the ionospheric radiation of the antenna system is greatly reduced with respect to an antenna 22 without a hood.
  • the gain of the antenna system (expressed in dB relative to the maximum radiation of the antennal system) is between 0 and -5 dB for radiation angles in the ranges [-90 °, -60 °] and [60 °, 90 °], and is less than -10 dB in the range [-50 °, 50 °].
  • Figure 4 schematically shows in perspective an antenna system according to a third embodiment of the invention.
  • the antenna system comprises a PIFA-type antenna 22 (for Planar Inverted F-Shaped Antenna in English).
  • the antenna 22 is composed of two vertical radiating elements 34a, 34b connected to a horizontal radiating element 36.
  • the antennal system includes a single-wire wired cap 30 electrically connected to the antenna 22 at the center of the wire hood.
  • Figure 5 schematically shows in perspective an antenna system according to a fourth embodiment of the invention.
  • the antenna system comprises an antenna 22 of shortened whip antenna type.
  • the antenna 22 is a monopole antenna comprising a single radiating wire, and the antennal system comprises a single-wire wired cap 30 electrically connected to one end of the antenna 22 at the center of the wire hood 30.
  • FIGS 6, 7, 8, 10 and 11 show schematically in perspective an antenna system according to different embodiments comprising an antenna 22 in the form of M as described above with reference to the first embodiment.
  • FIGS. 6 and 7 respectively represent a fifth and a sixth embodiment of the invention, in which the wired cap 30 is single-stranded and is connected to the antenna in various arrangements, in particular connected to any point of the element 24 radiating horizontally in the fifth embodiment ( Figure 6) or at one end of the horizontal radiating element 24 in the sixth embodiment ( Figure 7).
  • wired cover 30 makes it possible in particular to adapt the antenna system in different configurations so as to adapt to the constraints of the environment in which the antenna system is arranged, the configurations having identical operations.
  • FIGS. 8, 10 and 11 respectively represent a seventh, an eighth and a ninth embodiment of the invention, in which the wired cover 30 is a so-called multi-strand cover, comprising a plurality of wired elements, here two strands 38a, 38b connected in their center and extending in different directions so as to form an angle a.
  • the strands are of the same length greater than 0.8 ⁇ 0 .
  • the cover is connected to the antenna in various arrangements, in particular connected to the center of the horizontal radiating element 24 in the seventh embodiment (FIG. 8), at any point of the horizontal element 24. radiating in the eighth embodiment ( Figure 10) or at one end of the horizontal radiating element 24 in the ninth embodiment ( Figure 11).
  • FIG. 9 represents a radiation pattern according to the yOz plane (referred to as the zenith radiation pattern) of the antenna system according to the seventh embodiment of the invention, in which each strand of the hood has a length of 1.1 ⁇ 0 , 1 horizontal radiating element of the antenna 22 has a length of 0.7 ⁇ 0 and the antenna has a height h of 0.08 ⁇ 0 .
  • the radiation of the antennal system is therefore mainly surface-wave radiation, and the ionospheric radiation of the antenna system is greatly reduced with respect to an antenna 22 without a hood.
  • the gain of the antenna system (expressed in dB relative to the maximum radiation of the antennal system) is between 0 and -5 dB for radiation angles in the ranges [-90 °, -60 °] and [60 °, 90 °], is less than -10 dB in the range [-50 °, 50 °], and less than -15 dB in the range [-40 °, 40 °].
  • FIGS 12, 13 and 14 show schematically in perspective an antenna system respectively according to a tenth, an eleventh and a twelfth embodiment.
  • Each antenna system comprises an M-shaped antenna 22 according to various particular embodiments.
  • the antenna 22 comprises three horizontal radiating elements 24a, 24b, 24c of the same length, each connected at their ends to a vertical radiating element and all connected at their center to a single radiating element 26b. vertical.
  • This embodiment of the antenna allows a broadening of the radiation frequency band of the antenna.
  • the system 22 antenna comprises a multi-strand wired cap 30 composed of two strands 38a, 38b, as described above, the ends of the strands being connected in pairs by connections 40a, 40b wired so as to form a surface cover, that is to say to say equivalent to a radiant surface.
  • This surface cover therefore has an enlarged operating frequency band in connection with the widening of the operating band of the antenna 22.
  • the antenna 22 comprises two horizontal radiating elements 24, 124 of different lengths each connected at their ends to a vertical radiating element and all connected at their center to a single vertical radiating element.
  • a first horizontal radiating element 24 is of length adapted to radiate at a first central frequency f 0 (associated with the wavelength ⁇ 0 ) and a second horizontal element 124 is of length adapted to radiate at a second central frequency f bis ( associated with the wavelength ⁇ bis ).
  • the antenna is called double resonance.
  • the antennal system comprises a wired cap 30 composed of several strands, here three strands 38a, 38b, 38c, arranged in parallel, of different lengths and connected at their ends.
  • a first strand 38b has a length greater than 0.8 ⁇ 0 and is adapted to radiate at the first center frequency f 0
  • two second and third strands 38a, 38c have a length greater than 0.8 and are adapted to radiate to the central frequency f bis .
  • the wired cap 30 is thus double resonance and allows the reduction of the ionospheric radiation for the center frequencies f 0 and f bis .
  • the antenna 22 comprises five vertical radiating elements 26a, 26b, 26c, 26d, 26e connected to the horizontal radiating element 24.
  • the antenna 22 comprises localized elements 42a, 42b, 42c, 42d disposed on two of the vertical radiating elements and on the horizontal radiating element 24, allowing the formation of current traps and / or for modifying the electrical lengths. of the antenna 22.
  • the localized elements may be resistive, capacitive (capacitors) or inductive (coils) elements. These Localized elements are commonly called "load" in English.
  • the antennal system 22 comprises two multi-stranded covers 30a, 30b connected to the horizontal radiating element of the antenna, each of the covers comprising two strands.
  • the hoods further comprise localized elements 42e, 42f, 42g, 42h, 42i, 42j, 42k, 421 allowing the formation of current traps and / or making it possible to modify the electrical lengths of the hoods.
  • the localized elements are resistive elements (for example a resistor), capacitive (for example a capacitor) or inductive elements (for example a coil).
  • the invention is not limited to the embodiments described.
  • at least one cover may be a volume type cover so as to further widen the bandwidth of the antennal system, the antenna system may comprise more than two covers, several antennas, etc.

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Abstract

The invention relates to a surface wave antenna system, comprising at least one antenna (22) electrically shorted in the vertical plane, having vertical or elliptical polarisation and being suitable for emitting/receiving radiation in at least one frequency band centred on a central frequency f0 associated with a central wavelength λ0, said antenna (22) being connected to a conducting medium (28) having a substantially horizontal surface, the antenna system being characterised in that it further comprises at least one wired cover (30) of length greater than or equal to 0.8 λ0, electrically connected to at least one antenna (22) at the centre of the cover (30), and suitable for radiating at least at the central frequency f0 of the antenna (22).

Description

SYSTÈME ANTENNAIRE À ONDES DE SURFACE  ANTENNAIRE SURFACE WAVE SYSTEM
1. Domaine technique de l'invention 1. Technical field of the invention
L'invention concerne un système antennaire. En particulier, l'invention concerne un système antennaire à polarisation verticale et/ou elliptique adapté pour émettre et/ou recevoir des ondes de surface dans une large bande de fréquence incluant notamment tout ou partie des fréquences basses, moyennes et hautes comprises entre 30 kHz environ et 30 MHz environ, soit des ondes kilométriques, hectométriques et décamétriques.  The invention relates to an antennal system. In particular, the invention relates to an antenna system with vertical and / or elliptical polarization adapted to emit and / or receive surface waves in a wide frequency band including in particular all or part of the low, medium and high frequencies between 30 kHz approximately 30 MHz, consisting of LF, MF and HF.
2. Arrière-plan technologique 2. Technological background
Actuellement, des pylônes rayonnants de grandes dimensions sont utilisés pour émettre de fortes puissances dans les bandes hectométriques. Ces pylônes présentent l'inconvénient d'être coûteux, de nécessiter un important terrain de sécurité pour leur installation, et d'être peu esthétiques et discrets. Ils ne sont pas optimisés pour une diffusion essentiellement par ondes de surface.  Currently, large radiating pylons are used to emit high power in the MF bands. These pylons have the disadvantage of being expensive, requiring a large safety ground for their installation, and being unattractive and discreet. They are not optimized for diffusion mainly by surface waves.
Les antennes utilisant uniquement une onde de surface comme vecteur de propagation sont très peu nombreuses. Les systèmes à ondes de surface actuels utilisent des antennes de type fouet ou biconique qui sont mal adaptées pour des applications radar.  Antennas using only a surface wave as propagation vector are very few. Current surface wave systems use whip or biconical antennas that are poorly suited for radar applications.
Les pylônes rayonnants et en général toutes les antennes à polarisation verticale par exemple de type fouet ou biconique génèrent essentiellement un champ d'onde d'espace (aussi appelé rayonnement ionosphérique) et sont coûteux et/ou très peu discrets.  Radiant towers and in general all antennas with vertical polarization, for example of the whip or biconical type, essentially generate a space wave field (also called ionospheric radiation) and are expensive and / or very little discrete.
Des solutions ont été proposées pour résoudre ces problèmes. La demande de brevet français F 2965978, déposée par le demandeur, propose une solution permettant de réduire de façon importante l'encombrement vertical de l'antenne, permettant ainsi une réduction des coûts d'implantation et une amélioration de la discrétion de l'antenne. En outre, l'antenne permet une amélioration de la propagation par ondes de surface et une diminution du rayonnement ionosphérique. Néanmoins, le rayonnement ionosphérique reste toutefois important, notamment pour des angles compris entre ±[20° ; 80°] autour de la normale au plan de sol sur lequel est disposé l'antenne. Ce rayonnement ionosphérique restant peut, dans certaines bandes de fréquences, engendrer des phénomènes d'atténuation (fading en anglais), notamment lorsque les ondes de surface et les ondes d'espace interfèrent, au niveau de la surface de la Terre, après propagation dans des milieux et par des chemins différents. Solutions have been proposed to solve these problems. The French patent application F 2965978, filed by the applicant, proposes a solution to significantly reduce the vertical size of the antenna, thus reducing implementation costs and improving the discretion of the antenna . In addition, the antenna provides improved surface wave propagation and decreased ionospheric radiation. Nevertheless, the ionospheric radiation remains important, especially for angles between ± [20 °; 80 °] around the normal to the ground plane on which the antenna is placed. This remaining ionospheric radiation can, in certain frequency bands, generate attenuation phenomena (fading in English), especially when the surface waves and the space waves interfere, at the surface of the Earth, after propagation in different environments and paths.
3. Objectifs de l'invention 3. Objectives of the invention
L'invention vise à pallier au moins certains des inconvénients des antennes connus.  The invention aims to overcome at least some of the disadvantages of known antennas.
En particulier, l'invention vise à fournir, dans au moins un mode de réalisation de l'invention, un système antennaire dont le rayonnement préférentiel est un rayonnement d'ondes de surface.  In particular, the invention aims to provide, in at least one embodiment of the invention, an antenna system whose preferential radiation is a surface wave radiation.
L'invention vise aussi à fournir, dans au moins un mode de réalisation, un système antennaire dont le rayonnement ionosphérique est diminué.  The invention also aims to provide, in at least one embodiment, an antennal system whose ionospheric radiation is reduced.
L'invention vise aussi à fournir, dans au moins un mode de réalisation de l'invention, un système antennaire simple à réaliser.  The invention also aims to provide, in at least one embodiment of the invention, a simple antenna system to achieve.
L'invention vise aussi à fournir, dans au moins un mode de réalisation, un système antennaire discret et dont l'encombrement vertical est faible.  The invention also aims to provide, in at least one embodiment, a discrete antennal system and whose vertical footprint is low.
L'invention vise aussi à fournir, dans au moins un mode de réalisation, un système antennaire dont la bande passante peut être facilement modifiée.  The invention also aims to provide, in at least one embodiment, an antenna system whose bandwidth can be easily modified.
4. Exposé de l'invention 4. Presentation of the invention
Pour ce faire, l'invention concerne un système antennaire à ondes de surface, comprenant :  To do this, the invention relates to an antenna system with surface waves, comprising:
au moins une antenne électriquement courte dans le plan vertical, à polarisation verticale ou elliptique et adapté pour émettre/recevoir un rayonnement dans au moins une bande de fréquence centrée sur une fréquence centrale f0 associée à une longueur d'onde centrale λ0, ladite antenne étant reliée à un milieu conducteur présentant une surface sensiblement horizontale, at least one vertical electrically short antenna, with vertical or elliptical polarization and adapted to emit / receive radiation in at least one frequency band centered on a central frequency f 0 associated with a central wavelength λ 0 , said antenna being connected to a conductive medium having a substantially horizontal surface,
le système antennaire étant caractérisé en ce qu'il comprend en outre :  the antenna system being characterized in that it further comprises:
au moins un capot filaire de longueur supérieure ou égale à 0,8 λ0, électriquement lié à au moins une antenne au niveau du centre du capot, et adaptée pour rayonner au moins à la fréquence centrale f0 de l'antenne. at least one wired cover of length greater than or equal to 0.8 λ 0 , electrically connected to at least one antenna at the center of the hood, and adapted to radiate at least the central frequency f 0 of the antenna.
On entend par antenne électriquement courte dans le plan vertical une antenne émettant un rayonnement dans une longueur d'onde préférentielle dite longueur d'onde centrale λ0, et dont l'encombrement vertical est inférieur à un quart de la longueur d'onde centrale. Si l'antenne émet sur une bande de fréquence, la longueur d'onde centrale correspond à la longueur d'onde associée à la fréquence centrale de la bande de fréquence. L'antenne est par exemple une antenne telle que décrite dans la demande de brevet français FR2965978, une antenne fouet, une antenne de type PIFA (pour Planar Inverted F-Shaped Antenna en anglais), antenne en forme de M, etc. The term "electrically short antenna" in the vertical plane means an antenna emitting radiation in a preferential wavelength called central wavelength λ 0 , and whose vertical space is less than a quarter of the central wavelength. If the antenna transmits on a frequency band, the central wavelength corresponds to the wavelength associated with the center frequency of the frequency band. The antenna is for example an antenna as described in the French patent application FR2965978, a whip antenna, a PIFA type antenna (for Planar Inverted F-Shaped Antenna in English), M-shaped antenna, etc.
Un système antennaire selon l'invention permet donc un rayonnement préférentiel en ondes de surfaces, ainsi que la réduction du rayonnement ionosphérique d'une antenne grâce à l'utilisation d'un ou plusieurs capots filaires, de façon à émettre uniquement des ondes de surface. Les capots filaires sont reliés électriquement à l'antenne, de façon à ce qu'une alimentation de l'antenne alimente aussi les capots filaires. De cette façon et grâce à leurs dimensions, les capots filaires rayonnent à la fréquence centrale f0 et permettent la modification du diagramme de rayonnement de l'antenne de façon à réduire le rayonnement ionosphérique du système antennaire. Les capots filaires sont formés d'un fil métallique ou d'un tube métallique de faible section. An antennal system according to the invention therefore allows preferential radiation in surface waves, as well as the reduction of the ionospheric radiation of an antenna through the use of one or more wired hoods, so as to emit only surface waves. . The wired hoods are electrically connected to the antenna, so that a power supply of the antenna also feeds the wired hoods. In this way and thanks to their dimensions, the wire hoods radiate at the center frequency f 0 and allow the modification of the antenna radiation pattern so as to reduce the ionospheric radiation of the antennal system. The wire covers are formed of a wire or a metal tube of small section.
De préférence, l'encombrement vertical du système antennaire est compris entre 0,05 λ0 et 0,3 λ0. Le système antennaire est donc discret. En outre, il est moins sensible au vent, au souffle, à la foudre, aux séismes, etc. Preferably, the vertical congestion of the antenna system is between 0.05 λ 0 and 0.3λ 0 . The antennal system is therefore discreet. In addition, it is less sensitive to wind, blast, lightning, earthquakes, etc.
De préférence, la longueur du capot filaire est inférieure ou égale à 2 λ0. Preferably, the length of the wire cover is less than or equal to 2λ 0 .
Avantageusement et selon l'invention, ladite au moins une antenne est configurée pour émettre/recevoir un rayonnement directif selon une direction de rayonnement, et au moins un capot filaire s'étend selon une direction principale sensiblement parallèle à la direction de rayonnement. Advantageously and according to the invention, said at least one antenna is configured to emit / receive directional radiation in a radiation direction, and at least one wire cover extends in a main direction substantially parallel to the radiation direction.
Selon cet aspect de l'invention, le rayonnement ionosphérique du système antennaire est réduit davantage dans la direction de rayonnement de l'antenne lorsque celle-ci est une antenne directive. According to this aspect of the invention, the ionospheric radiation of the antenna system is further reduced in the direction of radiation of the antenna when this one is a directional antenna.
Avantageusement et selon l'invention, au moins un capot filaire s'étend selon une direction formant un angle compris entre -10° et 10° avec la surface du milieu conducteur. Advantageously and according to the invention, at least one wire cover extends in a direction forming an angle of between -10 ° and 10 ° with the surface of the conductive medium.
De préférence, le capot filaire s'étend selon une direction sensiblement parallèle à la surface du milieu conducteur. On entend par sensiblement parallèle un angle entre la direction de chaque capot et la surface du milieu conducteur compris entre -5° et 5°. Le capot filaire peut aussi être strictement parallèle à la surface du milieu conducteur.  Preferably, the wired cover extends in a direction substantially parallel to the surface of the conductive medium. By substantially parallel means an angle between the direction of each cap and the surface of the conductive medium between -5 ° and 5 °. The wired cover can also be strictly parallel to the surface of the conductive medium.
Selon cet aspect de l'invention, la réduction du rayonnement ionosphérique et la directivité de l'antenne sont améliorées.  According to this aspect of the invention, the reduction of the ionospheric radiation and the directivity of the antenna are improved.
Avantageusement, un système antennaire selon l'invention comprend au moins deux capots filaires s'étendant dans des directions principales différentes l'une de l'autre. Advantageously, an antenna system according to the invention comprises at least two wire hoods extending in major directions different from each other.
Selon cet aspect de l'invention, la présence d'une pluralité de capots filaires permet une réduction du rayonnement ionosphérique améliorée dans plusieurs azimuts. Avantageusement et selon l'invention, le milieu conducteur comprend un plan de masse, auquel est reliée chaque antenne.  According to this aspect of the invention, the presence of a plurality of wire hoods allows reduction of the enhanced ionospheric radiation in several azimuths. Advantageously and according to the invention, the conductive medium comprises a ground plane to which each antenna is connected.
Selon cet aspect de l'invention, le plan de masse permet d'améliorer la conductivité du milieu conducteur si cette conductivité est trop faible. Avantageusement et selon l'invention, au moins un capot filaire comprend au moins un élément localisé adapté pour permettre la résonance dudit capot à une multitude de fréquence.  According to this aspect of the invention, the ground plane makes it possible to improve the conductivity of the conducting medium if this conductivity is too low. Advantageously and according to the invention, at least one wire cover comprises at least one localized element adapted to allow the resonance of said cover at a multitude of frequencies.
Selon cet aspect de l'invention, les éléments localisés, qui peuvent être des éléments résistifs, capacitifs ou inductifs, permettent de former sur le ou les capots des circuits ouverts (ou haute impédance) ou des circuits fermés selon les fréquences de fonctionnement, formant ainsi des pièges de courant. Les éléments localisés sont ainsi adaptés pour obtenir un système antennaire multifréquence (c'est-à-dire à multiples résonances) via lesdits pièges de courant. According to this aspect of the invention, the localized elements, which may be resistive, capacitive or inductive elements, make it possible to form on the cover (s) open circuits (or high impedance) or closed circuits according to the operating frequencies, forming as well as current traps. The localized elements are thus adapted to obtain a multifrequency (i.e. multiple resonant) antenna system via said current traps.
En outre, les éléments localisés peuvent aussi permettre de reproduire la résonance LC du capot avec une longueur physique de capot réduite mais une longueur électrique équivalente. Les éléments localisés sont ainsi adaptés pour modifier la longueur électrique du capot.  In addition, the localized elements may also make it possible to reproduce the LC resonance of the hood with a reduced physical cover length but an equivalent electrical length. The localized elements are thus adapted to modify the electrical length of the hood.
Avantageusement et selon l'invention, au moins un capot filaire comprend une pluralité d'éléments filaires reliés les uns aux autres de sorte à former un capot surfacique ou un capot volumique. Advantageously and according to the invention, at least one wire cover comprises a plurality of wire elements connected to each other so as to form a surface cover or a volume cover.
Selon cet aspect de l'invention, les capots surfaciques ou volumiques permettent d'augmenter la largeur de bande passante du système antennaire. Ainsi, les capots surfaciques ou volumiques sont adaptés pour être utilisés avec des antennes à large bande. Les éléments filaires sont par exemple des brins composés de tubes ou de fils métalliques.  According to this aspect of the invention, the surface or volume covers allow to increase the bandwidth of the antennal system. Thus, the surface or volume covers are adapted for use with broadband antennas. The wire elements are, for example, strands made of tubes or metal wires.
L'invention concerne également un système antennaire caractérisé en combinaison par tout ou partie des caractéristiques mentionnées ci-dessus ou ci-après. The invention also relates to an antenna system characterized in combination by all or some of the characteristics mentioned above or below.
5. Liste des figures 5. List of figures
D'autres buts, caractéristiques et avantages de l'invention apparaîtront à la lecture de la description suivante donnée à titre uniquement non limitatif et qui se réfère aux figures annexées dans lesquelles :  Other objects, features and advantages of the invention will become apparent on reading the following description given solely by way of non-limiting example and which refers to the appended figures in which:
la figure 1 est une vue schématique en perspective d'un système antennaire selon un premier mode de réalisation de l'invention,  FIG. 1 is a schematic perspective view of an antenna system according to a first embodiment of the invention,
- la figure 2 est une vue schématique en perspective d'un système antennaire selon un deuxième mode de réalisation de l'invention, FIG. 2 is a schematic perspective view of an antenna system according to a second embodiment of the invention,
la figure 3 est un diagramme de rayonnement selon le plan yOz du système antennaire selon le deuxième mode de réalisation de l'invention,  FIG. 3 is a radiation diagram along the yOz plane of the antenna system according to the second embodiment of the invention,
la figure 4 est une vue schématique en perspective d'un système antennaire selon un troisième mode de réalisation de l'invention,  FIG. 4 is a schematic perspective view of an antenna system according to a third embodiment of the invention,
la figure 5 est une vue schématique en perspective d'un système antennaire selon un quatrième mode de réalisation de l'invention, FIG. 5 is a schematic perspective view of an antenna system according to a fourth embodiment of the invention,
la figure 6 est une vue schématique en perspective d'un système antennaire selon un cinquième mode de réalisation de l'invention,  FIG. 6 is a schematic perspective view of an antenna system according to a fifth embodiment of the invention,
la figure 7 est une vue schématique en perspective d'un système antennaire selon un sixième mode de réalisation de l'invention,  FIG. 7 is a schematic perspective view of an antenna system according to a sixth embodiment of the invention,
la figure 8 est une vue schématique en perspective d'un système antennaire selon un septième mode de réalisation de l'invention,  FIG. 8 is a schematic perspective view of an antenna system according to a seventh embodiment of the invention,
la figure 9 est un diagramme de rayonnement selon le plan yOz du système antennaire selon le septième mode de réalisation de l'invention,  FIG. 9 is a radiation diagram according to the yOz plane of the antenna system according to the seventh embodiment of the invention,
la figure 10 est une vue schématique en perspective d'un système antennaire selon un huitième mode de réalisation de l'invention,  FIG. 10 is a schematic perspective view of an antenna system according to an eighth embodiment of the invention,
la figure 11 est une vue schématique en perspective d'un système antennaire selon un neuvième mode de réalisation de l'invention,  FIG. 11 is a schematic perspective view of an antenna system according to a ninth embodiment of the invention,
la figure 12 est une vue schématique en perspective d'un système antennaire selon un dixième mode de réalisation de l'invention,  FIG. 12 is a schematic perspective view of an antenna system according to a tenth embodiment of the invention,
la figure 13 est une vue schématique en perspective d'un système antennaire selon un onzième mode de réalisation de l'invention,  FIG. 13 is a schematic perspective view of an antenna system according to an eleventh embodiment of the invention,
la figure 14 est une vue schématique en perspective d'un système antennaire selon un douzième mode de réalisation de l'invention.  Figure 14 is a schematic perspective view of an antenna system according to a twelfth embodiment of the invention.
6. Description détaillée d'un mode de réalisation de l'invention 6. Detailed description of an embodiment of the invention
Les réalisations suivantes sont des exemples. Bien que la description se réfère à un ou plusieurs modes de réalisation, ceci ne signifie pas nécessairement que chaque référence concerne le même mode de réalisation, ou que les caractéristiques s'appliquent seulement à un seul mode de réalisation. De simples caractéristiques de différents modes de réalisation peuvent également être combinées pour fournir d'autres réalisations. Sur les figures, les échelles et les proportions ne sont pas strictement respectées et ce, à des fins d'illustration et de clarté.  The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments. Figures, scales and proportions are not strictly adhered to for the purpose of illustration and clarity.
Un repère orthogonal Oxyz est utilisé sur chaque figure représentant des systèmes antennaires selon les différents modes de réalisation de l'invention.  An Oxyz orthogonal coordinate system is used on each figure representing antenna systems according to the various embodiments of the invention.
Les notions de « horizontal » et « vertical » sont utilisées en correspondance avec une antenne une fois installée, en situation opérationnelle, comme représenté figure 1. En outre, un élément est horizontal si sa direction principale est parallèle au plan xOy et est vertical si sa direction principale est parallèle à l'axe Oz. The notions of "horizontal" and "vertical" are used in correspondence with an antenna once installed, in an operational situation, as shown In addition, an element is horizontal if its principal direction is parallel to the plane xOy and is vertical if its principal direction is parallel to the axis Oz.
La figure 1 représente schématiquement en perspective un système 20 antennaire selon un premier mode de réalisation de l'invention. Figure 1 shows schematically in perspective an antenna system according to a first embodiment of the invention.
Le système 20 antennaire comprend une antenne 22, ici une antenne en forme de M comprenant un élément 24 rayonnant horizontal relié à trois éléments 26a, 26b, 26c rayonnants verticaux, eux-mêmes reliés à un milieu 28 conducteur. Sur cette figure et sur les figures suivantes, le milieu 28 conducteur est représenté par un symbole de masse électrique reliée à la terre. Le milieu 28 conducteur est un milieu conducteur imparfait, par exemple un sol (en terre, sable, etc.) ou de l'eau (mer, marais salant, lac, etc.). L'antenne est alimentée au niveau de l'élément 26b rayonnant vertical par un générateur 29.  The antenna system comprises an antenna 22, here an M-shaped antenna comprising a horizontal radiating element 24 connected to three vertical radiating elements 26a, 26b, 26c, themselves connected to a conductive medium 28. In this figure and in the following figures, the conductive medium 28 is represented by an electric ground symbol connected to the ground. Conductive medium 28 is an imperfect conductive medium, for example soil (earth, sand, etc.) or water (sea, salt marsh, lake, etc.). The antenna is fed at the level of the vertical radiating element 26b by a generator 29.
Le système 20 antennaire comprend en outre un capot 30 filaire relié électriquement à l'antenne 22 au niveau du centre du capot. En outre, dans ce mode de réalisation, le capot 30 filaire est relié à l'antenne 22 au niveau du centre de l'élément 24 rayonnant vertical.  The antenna system further includes a wire hood 30 electrically connected to the antenna 22 at the center of the hood. In addition, in this embodiment, the wire hood 30 is connected to the antenna 22 at the center of the vertical radiating element 24.
Le capot 30 filaire est monobrin (c'est-à-dire qu'il est composé d'un seul fil rayonnant), a une longueur supérieure à 0,8 λ0 et s'étend dans une direction sensiblement parallèle à la surface du milieu 28 conducteur. The wired cap 30 is single stranded (i.e. it is composed of a single radiating wire), has a length greater than 0.8λ 0 and extends in a direction substantially parallel to the surface of the middle 28 conductor.
Le milieu 28 conducteur a une conductivité électrique qui varie en fonction de sa composition. Par exemple, la mer, les marais salants ou les lacs salés ont une forte conductivité électrique, et la terre et le sable ont une faible conductivité électrique. Selon un mode de réalisation non représenté, si la conductivité électrique est trop faible, c'est-à-dire inférieure à 1 S/m, le système 20 antennaire est complété par un plan de masse, relié à l'antenne 22, et enfoui en dessous ou à la surface du milieu 28 conducteur. Le plan de masse peut être formé d'une plaque, ou d'un ensemble de fils conducteurs formant un grillage, etc. Le plan de masse peut prendre plusieurs formes, par exemple un cercle, un polygone (régulier ou non), etc. Le plan de masse s'étend sous l'ensemble du système 20 antennaire, c'est-à-dire que la projection du système 20 antennaire sur le milieu 28 conducteur selon l'axe Oz est comprise dans la surface occupée par le plan de masse. The conductive medium 28 has an electrical conductivity which varies according to its composition. For example, the sea, salt marshes or salt lakes have high electrical conductivity, and the earth and sand have low electrical conductivity. According to a not shown embodiment, if the electrical conductivity is too low, that is to say less than 1 S / m, the antenna system is completed by a ground plane, connected to the antenna 22, and buried below or on the surface of the conductive medium 28. The ground plane may be formed of a plate, or a set of conductive wires forming a grid, etc. The ground plane can take many forms, for example a circle, a polygon (regular or not), etc. The ground plane extends below the entire antennal system, i.e., the projection of the antenna system onto the conductive medium 28 along the Oz axis is included in the surface occupied by the mass plan.
La figure 2 représente schématiquement en perspective un système 20 antennaire selon un deuxième mode de réalisation de l'invention. Figure 2 schematically shows in perspective an antenna system according to a second embodiment of the invention.
Le système 20 antennaire comprend une antenne 22 telle que décrite dans la demande de brevet français FR2965978 déposée par le demandeur. Le système 20 antennaire comprend un capot 30 filaire relié électriquement à l'antenne 22 au niveau du centre du capot.  The antenna system comprises an antenna 22 as described in the French patent application FR2965978 filed by the applicant. The antenna system includes a wire hood 30 electrically connected to the antenna 22 at the center of the hood.
Le capot 30 filaire est monobrin, et est composé de deux sous-brins 32a, 32b de longueurs égales, reliés à une de leurs extrémités et disposés dans un même plan. Les deux sous-brins sont reliés en formant un angle, dû à la différence entre la hauteur hl à laquelle les sous-brins sont connectés et à la hauteur des deux autres extrémités des sous-brins. En particulier, lorsque les hauteurs hl et h2 sont égales, l'angle est égal à 180° et donc les sous-brins sont alignés et le capot est parallèle à la surface du milieu 28 conducteur, comme le capot décrit précédemment dans le premier mode de réalisation.  The wired cap 30 is single strand, and is composed of two sub-strands 32a, 32b of equal lengths, connected to one of their ends and arranged in the same plane. The two sub-strands are connected at an angle, due to the difference between the height h1 at which the sub-strands are connected and at the height of the other two ends of the sub-strands. In particular, when the heights h1 and h2 are equal, the angle is equal to 180 ° and therefore the sub-strands are aligned and the cover is parallel to the surface of the conductive medium 28, as the hood described above in the first mode of realization.
La figure 3 représente un diagramme de rayonnement selon le plan yOz (dit diagramme de rayonnement zénithal) du système antennaire selon le deuxième mode de réalisation de l'invention, dans lequel le capot filaire a une longueur de 0,8 λ0, la hauteur hl est égale à 0,06 λ0, la hauteur h2 est égale à 0,05 λ0 et la longueur L de l'antenne est égale à 0,3 λ0. FIG. 3 represents a radiation pattern according to the yOz plane (referred to as the zenith radiation pattern) of the antenna system according to the second embodiment of the invention, in which the wired cap has a length of 0.8λ 0 , the height hl is equal to 0.06 λ 0 , the height h2 is equal to 0.05 λ 0 and the length L of the antenna is equal to 0.3λ 0 .
Le rayonnement du système antennaire est donc principalement un rayonnement en ondes de surfaces, et le rayonnement ionosphérique du système antennaire est fortement réduit par rapport à une antenne 22 sans capot. En particulier, le gain du système antennaire (exprimé en dB par rapport au rayonnement maximal du système antennaire) est compris entre 0 et -5 dB pour des angles de rayonnement compris dans les intervalles [-90°, -60°] et [60°, 90°], et est inférieur à -lOdB dans l'intervalle [-50°, 50°].  The radiation of the antennal system is therefore mainly surface-wave radiation, and the ionospheric radiation of the antenna system is greatly reduced with respect to an antenna 22 without a hood. In particular, the gain of the antenna system (expressed in dB relative to the maximum radiation of the antennal system) is between 0 and -5 dB for radiation angles in the ranges [-90 °, -60 °] and [60 °, 90 °], and is less than -10 dB in the range [-50 °, 50 °].
La figure 4 représente schématiquement en perspective un système 20 antennaire selon un troisième mode de réalisation de l'invention. Figure 4 schematically shows in perspective an antenna system according to a third embodiment of the invention.
Le système 20 antennaire comprend une antenne 22 de type PIFA (pour Planar Inverted F-Shaped Antenna en anglais). L'antenne 22 est composée de deux éléments 34a, 34b rayonnants verticaux reliés à un élément 36 rayonnant horizontal. The antenna system comprises a PIFA-type antenna 22 (for Planar Inverted F-Shaped Antenna in English). The antenna 22 is composed of two vertical radiating elements 34a, 34b connected to a horizontal radiating element 36.
Le système 20 antennaire comprend un capot 30 filaire monobrin relié électriquement à l'antenne 22 au niveau du centre du capot 30 filaire.  The antennal system includes a single-wire wired cap 30 electrically connected to the antenna 22 at the center of the wire hood.
La figure 5 représente schématiquement en perspective un système 20 antennaire selon un quatrième mode de réalisation de l'invention. Figure 5 schematically shows in perspective an antenna system according to a fourth embodiment of the invention.
Le système 20 antennaire comprend une antenne 22 de type antenne fouet raccourcie. L'antenne 22 est une antenne monopôle comprenant un unique fil rayonnant, et le système 20 antennaire comprend un capot 30 filaire monobrin relié électriquement à une extrémité de l'antenne 22 au niveau du centre du capot 30 filaire.  The antenna system comprises an antenna 22 of shortened whip antenna type. The antenna 22 is a monopole antenna comprising a single radiating wire, and the antennal system comprises a single-wire wired cap 30 electrically connected to one end of the antenna 22 at the center of the wire hood 30.
Les figures 6, 7, 8, 10 et 11 représentent schématiquement en perspective un système 20 antennaire selon différents modes de réalisation comprenant une antenne 22 en forme de M telle que décrite précédemment en référence au premier mode de réalisation. Figures 6, 7, 8, 10 and 11 show schematically in perspective an antenna system according to different embodiments comprising an antenna 22 in the form of M as described above with reference to the first embodiment.
Les figures 6 et 7 représentent respectivement un cinquième et un sixième mode de réalisation de l'invention, dans lesquels le capot 30 filaire est monobrin et est relié à l'antenne selon différentes dispositions, notamment relié à un point quelconque de l'élément 24 rayonnant horizontal dans le cinquième mode de réalisation (figure 6) ou à une des extrémités de l'élément 24 rayonnant horizontal dans le sixième mode de réalisation (figure 7).  FIGS. 6 and 7 respectively represent a fifth and a sixth embodiment of the invention, in which the wired cap 30 is single-stranded and is connected to the antenna in various arrangements, in particular connected to any point of the element 24 radiating horizontally in the fifth embodiment (Figure 6) or at one end of the horizontal radiating element 24 in the sixth embodiment (Figure 7).
Ces différentes dispositions du capot 30 filaire permettent notamment d'adapter le système 20 antennaire selon différentes configurations de façon à s'adapter aux contraintes de l'environnement dans lequel est disposé le système 20 antennaire, les configurations ayant des fonctionnements identiques.  These different provisions of the wired cover 30 make it possible in particular to adapt the antenna system in different configurations so as to adapt to the constraints of the environment in which the antenna system is arranged, the configurations having identical operations.
Les figures 8, 10 et 11 représentent respectivement un septième, un huitième et un neuvième mode de réalisation de l'invention, dans lequel le capot 30 filaire est un capot dit multibrins, comprenant une pluralité d'éléments filaires, ici deux brins 38a, 38b reliés en leur centre et s' étendant dans des directions différentes de façon à former un angle a. Les brins sont de même longueur supérieure à 0,8 λ0. FIGS. 8, 10 and 11 respectively represent a seventh, an eighth and a ninth embodiment of the invention, in which the wired cover 30 is a so-called multi-strand cover, comprising a plurality of wired elements, here two strands 38a, 38b connected in their center and extending in different directions so as to form an angle a. The strands are of the same length greater than 0.8 λ 0 .
Selon les modes de réalisation, le capot est relié à l'antenne selon différentes dispositions, notamment relié au centre de l'élément 24 horizontal rayonnant dans le septième mode de réalisation (figure 8), à un point quelconque de l'élément 24 horizontal rayonnant dans le huitième mode de réalisation (figure 10) ou à une des extrémités de l'élément 24 rayonnant horizontal dans le neuvième mode de réalisation (figure 11).  According to the embodiments, the cover is connected to the antenna in various arrangements, in particular connected to the center of the horizontal radiating element 24 in the seventh embodiment (FIG. 8), at any point of the horizontal element 24. radiating in the eighth embodiment (Figure 10) or at one end of the horizontal radiating element 24 in the ninth embodiment (Figure 11).
La figure 9 représente un diagramme de rayonnement selon le plan yOz (dit diagramme de rayonnement zénithal) du système antennaire selon le septième mode de réalisation de l'invention, dans lequel chaque brin du capot a une longueur de 1,1 λ0, l'élément 24 rayonnant horizontal de l'antenne 22 a une longueur de 0,7 \0 et l'antenne a une hauteur h de 0,08 λ0. FIG. 9 represents a radiation pattern according to the yOz plane (referred to as the zenith radiation pattern) of the antenna system according to the seventh embodiment of the invention, in which each strand of the hood has a length of 1.1 λ 0 , 1 horizontal radiating element of the antenna 22 has a length of 0.7 \ 0 and the antenna has a height h of 0.08 λ 0 .
Le rayonnement du système antennaire est donc principalement un rayonnement en ondes de surfaces, et le rayonnement ionosphérique du système antennaire est fortement réduit par rapport à une antenne 22 sans capot. En particulier, le gain du système antennaire (exprimé en dB par rapport au rayonnement maximal du système antennaire) est compris entre 0 et -5 dB pour des angles de rayonnement compris dans les intervalles [-90°, -60°] et [60°, 90°], est inférieur à -lOdB dans l'intervalle [-50°, 50°], et inférieur à -15dB dans l'intervalle [-40°, 40°].  The radiation of the antennal system is therefore mainly surface-wave radiation, and the ionospheric radiation of the antenna system is greatly reduced with respect to an antenna 22 without a hood. In particular, the gain of the antenna system (expressed in dB relative to the maximum radiation of the antennal system) is between 0 and -5 dB for radiation angles in the ranges [-90 °, -60 °] and [60 °, 90 °], is less than -10 dB in the range [-50 °, 50 °], and less than -15 dB in the range [-40 °, 40 °].
Les figures 12, 13 et 14 représentent schématiquement en perspective un système 20 antennaire respectivement selon un dixième, un onzième et un douzième mode de réalisation. Chaque système antennaire comprend une antenne 22 en forme de M selon différents modes de réalisation particuliers. Figures 12, 13 and 14 show schematically in perspective an antenna system respectively according to a tenth, an eleventh and a twelfth embodiment. Each antenna system comprises an M-shaped antenna 22 according to various particular embodiments.
Dans le dixième mode de réalisation représenté figure 12, l'antenne 22 comprend trois éléments 24a, 24b, 24c rayonnants horizontaux de mêmes longueurs, chacun reliés à leurs extrémités à un élément rayonnant vertical et tous reliés en leur centre à un unique élément 26b rayonnant vertical. Ce mode de réalisation de l'antenne permet un élargissement de la bande de fréquence de rayonnement de l'antenne.  In the tenth embodiment shown in FIG. 12, the antenna 22 comprises three horizontal radiating elements 24a, 24b, 24c of the same length, each connected at their ends to a vertical radiating element and all connected at their center to a single radiating element 26b. vertical. This embodiment of the antenna allows a broadening of the radiation frequency band of the antenna.
Pour être adapté à cet élargissement de la bande de fréquence, le système 22 antennaire comprend un capot 30 filaire multibrin composé de deux brins 38a, 38b, tel que décrit précédemment, les extrémités des brins étant reliées deux à deux par des connexions 40a, 40b filaires de façon à former un capot surfacique, c'est-à-dire équivalent à une surface rayonnante. Ce capot surfacique a donc une bande de fréquence de fonctionnement élargie en lien avec l'élargissement de la bande de fonctionnement de l'antenne 22. To be adapted to this widening of the frequency band, the system 22 antenna comprises a multi-strand wired cap 30 composed of two strands 38a, 38b, as described above, the ends of the strands being connected in pairs by connections 40a, 40b wired so as to form a surface cover, that is to say to say equivalent to a radiant surface. This surface cover therefore has an enlarged operating frequency band in connection with the widening of the operating band of the antenna 22.
Dans le onzième mode de réalisation représenté figure 13, l'antenne 22 comprend deux éléments 24, 124 rayonnants horizontaux de longueurs différentes chacun reliés à leurs extrémités à un élément rayonnant vertical et tous reliés en leur centre à un unique élément rayonnant vertical. Un premier élément 24 rayonnant horizontal est de longueur adaptée pour rayonner à une première fréquence centrale f0 (associée à la longueur d'onde λ0) et un deuxième élément 124 horizontal est de longueur adaptée pour rayonner à une deuxième fréquence centrale fbis (associée à la longueur d'onde \bis). L'antenne est dite à double résonance. In the eleventh embodiment shown in Figure 13, the antenna 22 comprises two horizontal radiating elements 24, 124 of different lengths each connected at their ends to a vertical radiating element and all connected at their center to a single vertical radiating element. A first horizontal radiating element 24 is of length adapted to radiate at a first central frequency f 0 (associated with the wavelength λ 0 ) and a second horizontal element 124 is of length adapted to radiate at a second central frequency f bis ( associated with the wavelength \ bis ). The antenna is called double resonance.
Pour être adapté à cette double résonance, le système 22 antennaire comprend un capot 30 filaire composés de plusieurs brins, ici trois brins 38a, 38b, 38c, disposés parallèlement, de longueurs différentes et reliés à leurs extrémités. Un premier brin 38b a une longueur supérieure à 0,8 \0 et est adapté pour rayonner à la première fréquence centrale f0, et deux seconds et troisième brins 38a, 38c ont une longueur supérieure à 0,8 et sont adaptés pour rayonner à la fréquence centrale fbis. Le capot 30 filaire est ainsi à double résonance et permet la réduction du rayonnement ionosphérique pour les fréquences centrales f0 et fbis. Dans le douzième mode de réalisation représenté figure 14, l'antenne 22 comprend cinq éléments 26a, 26b, 26c, 26d, 26e rayonnants verticaux reliés à l'élément 24 rayonnant horizontal. En outre, l'antenne 22 comprend des éléments 42a, 42b, 42c, 42d localisés disposés sur deux des éléments rayonnants verticaux et sur l'élément 24 rayonnant horizontal, permettant la formation de pièges de courant et/ou permettant de modifier les longueurs électriques de l'antenne 22. Les éléments localisés peuvent être des éléments résistifs, capacitifs (condensateurs) ou inductifs (bobines). Ces éléments localisés sont couramment appelés « load » en anglais. To be adapted to this double resonance, the antennal system comprises a wired cap 30 composed of several strands, here three strands 38a, 38b, 38c, arranged in parallel, of different lengths and connected at their ends. A first strand 38b has a length greater than 0.8 \ 0 and is adapted to radiate at the first center frequency f 0 , and two second and third strands 38a, 38c have a length greater than 0.8 and are adapted to radiate to the central frequency f bis . The wired cap 30 is thus double resonance and allows the reduction of the ionospheric radiation for the center frequencies f 0 and f bis . In the twelfth embodiment shown in FIG. 14, the antenna 22 comprises five vertical radiating elements 26a, 26b, 26c, 26d, 26e connected to the horizontal radiating element 24. In addition, the antenna 22 comprises localized elements 42a, 42b, 42c, 42d disposed on two of the vertical radiating elements and on the horizontal radiating element 24, allowing the formation of current traps and / or for modifying the electrical lengths. of the antenna 22. The localized elements may be resistive, capacitive (capacitors) or inductive (coils) elements. These Localized elements are commonly called "load" in English.
Le système 22 antennaire comprend deux capots 30a, 30b multibrins reliés à l'élément rayonnant horizontal de l'antenne, chacun des capots comprenant deux brins. Les capots comprennent en outre des éléments 42e, 42f, 42g, 42h, 42i, 42j, 42k, 421 localisés permettant la formation de pièges de courant et/ou permettant de modifier les longueurs électriques des capots.  The antennal system 22 comprises two multi-stranded covers 30a, 30b connected to the horizontal radiating element of the antenna, each of the covers comprising two strands. The hoods further comprise localized elements 42e, 42f, 42g, 42h, 42i, 42j, 42k, 421 allowing the formation of current traps and / or making it possible to modify the electrical lengths of the hoods.
Les éléments localisés sont des éléments résistifs (par exemple une résistance), capacitifs (par exemple un condensateur) ou inductifs (par exemple une bobine). L'invention ne se limite pas aux seuls modes de réalisation décrits. En particulier, au moins un capot peut être un capot de type volumique de façon à élargir davantage la bande passante du système antennaire, le système antennaire peut comprendre plus de deux capots, plusieurs antennes, etc.  The localized elements are resistive elements (for example a resistor), capacitive (for example a capacitor) or inductive elements (for example a coil). The invention is not limited to the embodiments described. In particular, at least one cover may be a volume type cover so as to further widen the bandwidth of the antennal system, the antenna system may comprise more than two covers, several antennas, etc.

Claims

REVENDICATIONS
1. Système antennaire à ondes de surface, comprenant : Antenna surface wave system, comprising:
au moins une antenne (22) électriquement courte dans le plan vertical, à polarisation verticale ou elliptique et adaptée pour émettre/recevoir un rayonnement dans au moins une bande de fréquence centrée sur une fréquence centrale f0 associée à une longueur d'onde centrale λ0, ladite antenne (22) étant reliée à un milieu conducteur (28) présentant une surface sensiblement horizontale, at least one antenna (22) electrically short in the vertical plane, with vertical or elliptical polarization and adapted to emit / receive radiation in at least one frequency band centered on a central frequency f 0 associated with a central wavelength λ 0 , said antenna (22) being connected to a conductive medium (28) having a substantially horizontal surface,
le système antennaire étant caractérisé en ce qu'il comprend en outre :  the antenna system being characterized in that it further comprises:
au moins un capot (30, 30a, 30b) filaire de longueur supérieure ou égale à 0,8 λ0, électriquement lié à au moins une antenne (22) au niveau du centre du capot (30, 30a, 30b), et adapté pour rayonner au moins à la fréquence centrale f0 de l'antenne (22). at least one wired cover (30, 30a, 30b) of length greater than or equal to 0.8λ 0 , electrically connected to at least one antenna (22) at the center of the cover (30, 30a, 30b), and adapted to radiate at least at the center frequency f 0 of the antenna (22).
2. Système antennaire selon la revendication 1, caractérisé en ce que ladite au moins une antenne (22) est configurée pour émettre/recevoir un rayonnement directif selon une direction de rayonnement, et en ce qu'au moins un capot (30, 30a, 30b) filaire s'étend selon une direction principale sensiblement parallèle à la direction de rayonnement. 2. Antenna system according to claim 1, characterized in that said at least one antenna (22) is configured to emit / receive directional radiation in a radiation direction, and in that at least one cover (30, 30a, 30b) extends in a main direction substantially parallel to the direction of radiation.
3. Système antennaire selon l'une des revendications 1 ou 2, caractérisé en ce qu'au moins un capot (30, 30a, 30b) filaire s'étend selon une direction formant un angle compris entre -10° et 10° avec la surface du milieu (28) conducteur. 3. antennal system according to one of claims 1 or 2, characterized in that at least one wired cover (30, 30a, 30b) extends in a direction forming an angle between -10 ° and 10 ° with the middle surface (28) conductor.
4. Système antennaire selon l'une des revendications 1 à 3, caractérisé en ce qu'il comprend au moins deux capots (30a, 30b) filaires s'étendant dans des directions principales différentes l'une de l'autre. 4. Antenna system according to one of claims 1 to 3, characterized in that it comprises at least two covers (30a, 30b) wired extending in main directions different from each other.
5. Système antennaire selon l'une des revendications 1 à 4, caractérisé en ce que le milieu (28) conducteur comprend un plan (38) de masse, auquel est reliée chaque antenne (22). 5. Antenna system according to one of claims 1 to 4, characterized in that the conductive medium (28) comprises a plane (38) of mass to which is connected each antenna (22).
6. Système antennaire selon l'une des revendications 1 à 5, caractérisé en ce qu'au moins un capot (30, 30a, 30b) filaire comprend au moins un élément localisé (42e-42l) adapté pour permettre la résonance dudit capot (30, 30a, 30b) à une multitude de fréquence. 6. Antenna system according to one of claims 1 to 5, characterized in that at least one wired cover (30, 30a, 30b) comprises at least one localized element (42e-42l) adapted to allow the resonance of said cover ( 30, 30a, 30b) at a multitude of frequencies.
7. Système antennaire selon l'une des revendications 1 à 6, caractérisé en ce qu'au moins un capot (30, 30a, 30b) filaire comprend une pluralité d'éléments filaires reliés les uns aux autres de sorte à former un capot surfacique ou un capot volumique. 7. Antenna system according to one of claims 1 to 6, characterized in that at least one wired cover (30, 30a, 30b) comprises a plurality of wire elements connected to each other so as to form a surface hood or a volume hood.
PCT/FR2016/051916 2015-08-10 2016-07-22 Surface wave antenna system WO2017025674A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
ES16753413T ES2958409T3 (en) 2015-08-10 2016-07-22 Surface wave antenna system
EP16753413.0A EP3335268B1 (en) 2015-08-10 2016-07-22 Surface wave antenna system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1557655 2015-08-10
FR1557655A FR3040109B1 (en) 2015-08-10 2015-08-10 SURFACE WAVE ANTENNA SYSTEM

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WO2017025674A1 true WO2017025674A1 (en) 2017-02-16

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EP (1) EP3335268B1 (en)
ES (1) ES2958409T3 (en)
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WO (1) WO2017025674A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR608523A (en) * 1925-12-04 1926-07-28 Materiel Telephonique Antenna system
US2156661A (en) * 1936-04-29 1939-05-02 Rca Corp Wireless aerial
DE869650C (en) * 1941-05-01 1953-03-05 Telefunken Gmbh Trap-shaped antenna
GB2241384A (en) * 1990-02-02 1991-08-28 British Broadcasting Corp T-shaped antenna

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR608523A (en) * 1925-12-04 1926-07-28 Materiel Telephonique Antenna system
US2156661A (en) * 1936-04-29 1939-05-02 Rca Corp Wireless aerial
DE869650C (en) * 1941-05-01 1953-03-05 Telefunken Gmbh Trap-shaped antenna
GB2241384A (en) * 1990-02-02 1991-08-28 British Broadcasting Corp T-shaped antenna

Also Published As

Publication number Publication date
ES2958409T3 (en) 2024-02-08
EP3335268A1 (en) 2018-06-20
EP3335268B1 (en) 2023-07-19
FR3040109B1 (en) 2018-10-05
EP3335268C0 (en) 2023-07-19
FR3040109A1 (en) 2017-02-17

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