EP3227963B1 - Compact, multiband and optionally reconfigurable high-impedance surface device and associated process - Google Patents

Compact, multiband and optionally reconfigurable high-impedance surface device and associated process Download PDF

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Publication number
EP3227963B1
EP3227963B1 EP15808741.1A EP15808741A EP3227963B1 EP 3227963 B1 EP3227963 B1 EP 3227963B1 EP 15808741 A EP15808741 A EP 15808741A EP 3227963 B1 EP3227963 B1 EP 3227963B1
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EP
European Patent Office
Prior art keywords
cavity
compartments
electrically conductive
compartment
bottom wall
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EP15808741.1A
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German (de)
French (fr)
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EP3227963A1 (en
Inventor
Cédric MARTEL
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Office National dEtudes et de Recherches Aerospatiales ONERA
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Office National dEtudes et de Recherches Aerospatiales ONERA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/006—Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces
    • H01Q15/0066—Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces said selective devices being reconfigurable, tunable or controllable, e.g. using switches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
    • H01Q1/521—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure reducing the coupling between adjacent antennas
    • H01Q1/523—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure reducing the coupling between adjacent antennas between antennas of an array
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
    • H01Q1/521—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure reducing the coupling between adjacent antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
    • H01Q15/004—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective using superconducting materials or magnetised substrates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/006—Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0086—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
    • 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

Definitions

  • the invention relates to surface devices with high electromagnetic impedance (or HIS for "High Impedance Surface”).
  • high electromagnetic impedance surface devices are used.
  • the latter can, for example, be used to reduce inter-element electromagnetic coupling in multistandard adaptive networks.
  • a high electromagnetic impedance surface device generally comprises a ground plane, at least one dielectric cavity (generally in the form of a substrate), and a printed circuit board (or PCB) "Printed Circuit Board”)), monolayer or multilayer, and comprising a multitude of conductive elements defining patterns arranged periodically and whose size and periodicity are small compared to the wavelength used.
  • PCB printed circuit board
  • the high electromagnetic impedance surface device When it is desired that the high electromagnetic impedance surface device has at least two resonant frequencies, it can, for example, be arranged as described in the patent document. US 6,670,932 . More precisely, this high electromagnetic impedance surface device is of the mushroom type, that is to say it comprises a conductive ground plane defining a cavity that is not compartmentalized but comprising a matrix of identical conducting pillars, filled with a dielectric material and covered by a printed circuit board bearing metallic patterns, so as to constitute electromagnetic resonators having different resonant wavelengths. The size and periodicity of the elements (or “patches") defining the patterns is lower than the resonance wavelengths of the electromagnetic resonators.
  • Each pattern is intended to hook at the entrance of the cavity an incident electromagnetic wave which propagates in the ground plane, then to generate, under the pattern, a loop of electric current at a resonant frequency determined so as to reflect any incident electromagnetic wave having a frequency in a narrow band centered around this resonant frequency.
  • the described device provides an interleaving of a first "matrix" of electromagnetic resonators, identical and having a first resonance frequency, with a second "matrix” of electromagnetic resonators, identical and having a second resonant frequency.
  • This interlacing is obtained by the patterns that are carried by the printed circuit board of fractal or multilayer type, each pattern being centered either on a pillar or between four adjacent pillars.
  • the main disadvantage of this type of device lies in the fact that the first and second resonant frequencies can not be adjusted independently of one another and that the reflection bands, whose resonance frequencies are the central frequencies , are quite narrow.
  • this type of device is relatively bulky.
  • the object of the invention is therefore in particular to improve the situation, and more specifically to enable obtaining in a reduced space of frequencies (or resonant wavelengths) that can be easily adjusted relative to each other and defining the central frequencies (or wavelengths) of spectrally wider reflection bands than in the state of the art.
  • a high-impedance surface device comprising an assembly of at least two separate substantially cylindrical compartments having internal surfaces in a conductive material. electrical conductor, and each having, at one end, a single opening, these openings of the compartments being oriented on the same side and covered by at least one periodic structure of electrical conductive patterns, each compartment being filled with a dielectric material, each compartment thus covered forming at least one electromagnetic resonator, and each electromagnetic resonator having a resonant wavelength.
  • the invention also proposes a satellite positioning signal receiver, comprising an electric ground plane, at least two radiating elements disposed on this ground plane, and at least one high impedance surface device of the type presented above. , arranged on the ground plane between the radiating elements.
  • the invention also proposes a method for modifying the impedance over several frequency bands of a high-impedance surface device and comprising at least one step of modifying the electromagnetic properties of at least one compartment of the device.
  • a high impedance surface device of the type shown above.
  • the invention also provides a method for enabling the manufacture of a high impedance surface device which comprises a plurality of substantially cylindrical, separate compartments and a periodic structure of electrical conductive patterns.
  • the object of the invention is in particular to propose a compact, multi-banded and possibly reconfigurable high-impedance surface device 1 and associated methods.
  • the high impedance surface device 1 is part of a satellite positioning signal receiver 15, possibly of the GNSS type ("Global Navigation"). Satellite System "). But the invention is not limited to this application.
  • a high impedance surface device 1, according to the invention can indeed equip many devices, systems or installations, civil or military, and in particular land vehicles, maritime, river or air, transmitting stations and / or receivers, and buildings (possibly of industrial type).
  • this receiver 15 comprises a ground plane 16, at least two radiating elements 17 k disposed on this ground plane 16, and at least one high-impedance surface device 1 according to the invention, arranged on the plane of mass 16 between the radiating elements 17 k .
  • the radiating elements 17 k define an adaptive network capable of receiving navigation signals, for example GNSS signals, in a scrambled environment by modifying the radiation from the receiver to generate nulls (or zeros) of radiation in the interference interference directions.
  • the adaptation of the radiation pattern as a function of the jammers is carried out by means of a post-processing of the navigation signals received on each of the radiating elements 17 k of the network.
  • the receiver 15 may comprise any number of radiating elements 17 k , provided that this number is greater than or equal to two.
  • the high impedance surface device 1 can in particular reduce the electromagnetic coupling between radiating elements 17 k and optimize the robustness of the receiver 15 vis-à-vis electromagnetic interference.
  • a high impedance surface device 1 can be responsible for stopping the currents propagating between the radiating elements 17 k of the adaptive network in order to reduce the electromagnetic coupling between radiating elements and to optimize the robustness of the receiver GNSS with regard to electromagnetic interference.
  • a high impedance surface device 1 comprises at least one set of at least two compartments 2 j and at least one periodic structure of electrical conductive patterns 4.
  • the compartments 2 j of the assembly are separated and substantially cylindrical, have internal surfaces made of an electrically conductive material, and each have, at one end, a single opening 3.
  • each compartment 2 j is filled with a dielectric material, for example air.
  • the compartments 2 j are substantially cylindrical of rectangular or square section.
  • the openings 3 of the compartments 2 j are all oriented on the same side and covered by at least one periodic structure of electrical conductive patterns 4. It will be understood that each opening 3 can be associated with its own periodic structure of electrical conductive patterns 4, such as illustrated without limitation on Figures 5 and 6 or the openings 3 may be associated with the same periodic structure of electrical conductive patterns 4, as shown in non-limiting manner on the Figures 1 to 4 .
  • each compartment 2 j can be covered by a single electrical conductive pattern 4.
  • the electrical conductive patterns 4 of each periodic structure may be secured to support means, such as for example a printed circuit board (or PCB), 18 of type monolayer or multilayer.
  • support means such as for example a printed circuit board (or PCB), 18 of type monolayer or multilayer.
  • the electrical conductive patterns 4 can be printed on this printed circuit board 18.
  • the electrical conductive patterns 4 are arranged periodically and their size and periodicity are small compared to the wavelength used.
  • each pattern 4 may be a metal gate ensuring its own support function.
  • active elements such as, for example, varactors, may be optionally and previously integrated on / in the printed circuit board 18 to adjust the capacitive effect of the patterns 4.
  • the device 1 may optionally comprise first adjustment means arranged to adjust the dielectric permittivity of the support means.
  • the first adjustment means can be made in the form of materials whose properties can be controlled electronically, such as for example liquid crystals, plasmas or ferroelectric materials, and electronic control means of such materials.
  • the first adjustment means may be made in the form of an adjustable permittivity metamaterial.
  • the dielectric permittivity acts on the inductance of compartment 2 j . The higher the permittivity, the lower the height of compartment 2 j can be.
  • Each compartment 2 j forms with the periodic structure of electrical conductive patterns 4 which covers its opening 3 at least one electromagnetic resonator having a resonant frequency.
  • the compartments 2 j are separated from each other by a distance that is smaller than the shortest resonance wavelength presented by the electromagnetic resonators they form. Furthermore, at least two respective resonant wavelengths of electromagnetic resonators formed by the compartments 2 covered j are different.
  • the periodic structure of electrical conductive patterns 4 has a spatial period that is less than half of the lowest resonance wavelength.
  • the device 1 produces a high impedance effect at several frequencies (or wavelengths) of resonance.
  • the number of exploitable resonance frequencies (or wavelengths) is equal to the number of compartments.
  • the high impedance effect is produced on a fictitious surface which is located above the printed circuit board 18, very close and parallel to the printed circuit board 18 and can cover a larger or smaller surface depending on the frequency (or wavelength) of resonance considered.
  • the device 1 can be implemented according to exemplary embodiments which can be grouped together in at least two families.
  • a first family groups the illustrated examples on the Figures 1 to 4 .
  • a second family includes the illustrated examples on the Figures 5 and 6 .
  • the device 1 comprises a single cavity 5 in which each compartment 2 j is arranged (or defined).
  • the cavity 5 comprises at least one vertical partition 6 which is electrically conductive and in contact with a bottom wall 7 and which delimits two compartments 2 j .
  • Each vertical partition 6 is preferably substantially plane, and defines a plane substantially perpendicular to a plane defined by the bottom wall 7 of the cavity 5.
  • This electrical conductive character can come from the material in which the vertical partition 6 is made or the fact that the vertical partition 6 is coated on its surfaces with a layer of an electrically conductive material.
  • a single periodic structure of electrical conductive patterns 4 covers all the openings 3 of the different compartments 2 j .
  • the cavity 5 is delimited by at least one side wall 10 and the bottom wall 7.
  • the latter walls 7, 10 are electrically conductive.
  • This electrically conductive character can come from the material in which they are made or because they are coated with a layer of an electrically conductive material on their inner surfaces.
  • the cavity 5 can either be attached and secured to the ground plane 16, for example by welding or gluing, or be an integral part of the ground plane 16, for example by stamping and cutting.
  • the cavity 5 can comprise any number of compartments 2 j , provided that this number is greater than or equal to two.
  • This cavity 5 with multiple electromagnetic resonators produces capacitive and inductive effects ei which are at the origin of the high surface impedance.
  • capacitive effect between the ground plane 16 and each pattern 4 which overlaps it a capacitive effect between overlapping patterns 4, and an inductive effect ei in each compartment 2 j , more precisely in the depth hj of each compartment. 2 j , thus forming a current loop.
  • the vertical distances between the upper ends 11 of the vertical partitions 6 and the patterns 4 may be zero, the vertical partitions 6 being in this case in contact with the printed circuit board 18.
  • the resonance frequency setting can be made by adjusting both the distances lm and the heights hm. This solution is particularly advantageous when it is desired to obtain more than two resonance frequencies because it makes it possible to increase the degrees of freedom to optimize the device 1.
  • FIGS. Figures 1, 2 and 4 The choice of resonance frequencies by adjustment of the respective height hm of the vertical partitions 6 is illustrated on the figure 2 .
  • the choice of the resonant frequencies may be the subject of an initial design or of a preliminary adjustment, for example via appropriate adjustment means for given functions, or of a real-time adjustment by means of appropriate settings.
  • each vertical partition 6 can be movable in a direction which is substantially parallel to a plane defined by the bottom wall 7 of the cavity 5.
  • the device 1 may comprise adjustment means arranged to adjust the horizontal position of each vertical partition 6 in the cavity 5.
  • each vertical partition 6 can be movable in a direction (here vertical) which is substantially perpendicular to the plane defined by the bottom wall 7 of the cavity 5.
  • the device 1 may comprise adjusting means arranged to adjust the height of each vertical partition 6 in the cavity 5.
  • each compartment 2 j can be provided with an auxiliary bottom wall 8, distinct from the bottom wall 7 of the cavity 5, electrically conductive, and mounted vertically movable in the cavity 5. It will be understood that by varying the position (here vertical) hm of an auxiliary bottom wall 8 of a compartment 2 j , this amounts to varying the height in the cavity 5 of the corresponding vertical partition 6.
  • the device 1 may comprise adjustment means arranged to adjust the position (here vertical) of each auxiliary bottom wall 8 in its compartment 2 j .
  • each vertical partition 6 which extends opposite one of the electrical conductive patterns 4 may optionally have a flared section. This makes it possible to increase the capacitive effect between the vertical partition 6 and the patterns 4 of the printed circuit board 18.
  • the following method can be implemented. First, we can design a first single-band electromagnetic resonator on a frequency f1. Then, we can determine the number of vertical partitions 6 to set the number of resonance frequencies f1 to fn. Then, the vertical partitions 6 can be inserted into the cavity 5. The height of the cavity 5 can then be adjusted to obtain the first resonance frequency at the frequency f1. Finally, it is possible to adjust the distances lm and / or the heights hm to adjust the frequencies f2 to fn of the other resonant frequencies.
  • a method may be designed to allow the manufacture of a high impedance surface of device 1 which comprises a plurality of separate compartments 2 j, substantially cylindrical, and a periodic structure patterns electrical conductors 4.
  • the variation of the width of the first compartment 2 1 does not substantially change the first resonance frequency f1 but varies the second resonant frequency f2.
  • the resonant frequency f1 remains stable as a function of the distance 11, since the mode generated in the device 1 is the result of a resonance where the magnetic field moves vertically in the cavity 5 in an electromagnetic manner.
  • the vertical partition 6 in fact interacts with the electromagnetic field, and thus the field vanishes on a vertical line in the vicinity of the vertical partition 6 and produces a higher order mode than that observed at the resonance frequency f1.
  • the distance 11 thus conditions this resonance mode and affects the value of the resonant frequency f2.
  • the device 1 comprises at least two cavities 5 j disjoint forming (or defining) each one of the compartments 2 j.
  • the number of frequencies (or wavelengths) of resonance is here defined by the number of cavities 5 j .
  • each cavity 5j is associated with its own periodic pattern of electrical conductive patterns 4 which is defined on its own printed circuit board 18. But in a non-illustrated embodiment, each cavity 5j is associated with its own periodic structure of electrical conductive patterns 4, but the various periodic structures are defined on the same printed circuit board 18.
  • the cavities 5 j and therefore the electromagnetic resonators, share the same ground plane 16 and, as indicated above, are spaced apart from one another by a distance that is less than the smallest. resonance wavelength.
  • This family of exemplary embodiments has the particularity of producing successive high impedance effects for distinct resonant frequencies.
  • Each electromagnetic resonator is characterized by its own resonance frequency.
  • the high impedance effect is produced on a dummy surface located above the or each printed circuit board 18 and very close to, and parallel to, the or each printed circuit board 18.
  • the height hm of a cavity 5 j and the type of dielectric material in the cavity 5 j directly impact the inductance value, whereas the circuit board printed matter 18 tends to impact the value of the capacity.
  • the multi-resonant character obtained also with this family of exemplary embodiments proves unexpected, insofar as it was logical to think that the frequencies higher than the resonance frequency of the first cavity 5 1 could not cross the latter cavity 5 1 and reach the neighboring cavities 5 j (with j ⁇ 1).
  • the device 1 can comprise at least two horizontal partitions 9 j electrically conductive, each mounted vertically movable within one of the cavities 5 j, and each forming a bottom wall of one of the compartments 2 j.
  • the electrical conductive character can come from the material in which is made each horizontal partition 9 j or the fact that each horizontal partition 9 j is coated on its surfaces with a layer of an electrically conductive material.
  • the device 1 comprises adjustment means arranged to adjust the position (here vertical) of each horizontal partition 9 j in its cavity 5 j , and therefore its compartment 2 j .
  • the device 1 may optionally comprise second adjustment means arranged to adjust the magnetic permeability of the material filling each compartment 2 j .
  • the second adjustment means may be made in the form of a magnetic material of adjustable magnetic permeability, such as for example a ferromagnetic material or a metamaterial.
  • the second adjustment means can be made in the form of a ferrite whose magnetic permeability changes under the influence of a magnetic field.
  • the reflective band increases with the increase of the magnetic permeability of the material.
  • An adjustable magnetic permeability makes it possible to adjust the inductance.
  • a compact high-impedance surface device is available because it comprises a reduced number of cavities.
  • a multi-band high-impedance surface device is available, possibly reconfigurable, and adapted to spectrally wider reflection bands than in the state of the art.

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Description

Domaine techniqueTechnical area

L'invention concerne les dispositifs de surface à haute impédance électromagnétique (ou HIS pour « High Impedance Surface »).The invention relates to surface devices with high electromagnetic impedance (or HIS for "High Impedance Surface").

Etat de l'artState of the art

Dans certains domaines, comme par exemple celui des récepteurs de signaux de positionnement satellite, on utilise des dispositifs de surface à haute impédance électromagnétique. Ces derniers peuvent, par exemple, servir à réduire les couplages électromagnétiques inter-éléments dans des réseaux adaptatifs multistandard.In some areas, such as satellite positioning signal receivers, high electromagnetic impedance surface devices are used. The latter can, for example, be used to reduce inter-element electromagnetic coupling in multistandard adaptive networks.

Il est rappelé qu'un dispositif de surface à haute impédance électromagnétique comprend généralement un plan de masse, au moins une cavité diélectrique (généralement sous la forme d'un substrat), et une carte à circuits imprimés (ou PCB (de l'anglais « Printed Circuit Board »)), monocouche ou multicouches, et comportant une multitude d'éléments conducteurs définissant des motifs agencés périodiquement et dont la taille et la périodicité sont petites devant la longueur d'onde utilisée.It is recalled that a high electromagnetic impedance surface device generally comprises a ground plane, at least one dielectric cavity (generally in the form of a substrate), and a printed circuit board (or PCB) "Printed Circuit Board")), monolayer or multilayer, and comprising a multitude of conductive elements defining patterns arranged periodically and whose size and periodicity are small compared to the wavelength used.

Lorsque l'on souhaite que le dispositif de surface à haute impédance électromagnétique présente au moins deux fréquences de résonance, on peut, par exemple, l'agencer comme décrit dans le document brevet US 6,670,932 . Plus précisément, ce dispositif de surface à haute impédance électromagnétique est de type champignon, c'est-à-dire qu'il comprend un plan de masse conducteur définissant une cavité non compartimentée mais comportant une matrice de piliers identiques conducteurs, remplie d'un matériau diélectrique et recouverte par une carte à circuits imprimés portant des motifs métalliques, afin de constituer des résonateurs électromagnétiques présentant des longueurs d'onde de résonance différentes. La taille et la périodicité des éléments (ou « patchs ») définissant les motifs est inférieure aux longueurs d'onde de résonance des résonateurs électromagnétiques.When it is desired that the high electromagnetic impedance surface device has at least two resonant frequencies, it can, for example, be arranged as described in the patent document. US 6,670,932 . More precisely, this high electromagnetic impedance surface device is of the mushroom type, that is to say it comprises a conductive ground plane defining a cavity that is not compartmentalized but comprising a matrix of identical conducting pillars, filled with a dielectric material and covered by a printed circuit board bearing metallic patterns, so as to constitute electromagnetic resonators having different resonant wavelengths. The size and periodicity of the elements (or "patches") defining the patterns is lower than the resonance wavelengths of the electromagnetic resonators.

Chaque motif est destiné à accrocher à l'entrée de la cavité une onde électromagnétique incidente qui se propage dans le plan de masse, puis à générer, sous le motif, une boucle de courant électrique à une fréquence de résonance déterminée de manière à réfléchir toute onde électromagnétique incidente ayant une fréquence dans une bande étroite centrée autour de cette fréquence de résonance.Each pattern is intended to hook at the entrance of the cavity an incident electromagnetic wave which propagates in the ground plane, then to generate, under the pattern, a loop of electric current at a resonant frequency determined so as to reflect any incident electromagnetic wave having a frequency in a narrow band centered around this resonant frequency.

Le dispositif décrit offre un entrelacement d'une première « matrice » de résonateurs électromagnétiques, identiques et ayant une première fréquence de résonance, avec une seconde « matrice » de résonateurs électromagnétiques, identiques et ayant une seconde fréquence de résonance. Cet entrelacement est obtenu par les motifs qui sont portés par la carte à circuits imprimés de type fractal ou multicouches, chaque motif étant centré soit sur un pilier soit entre quatre piliers voisins.The described device provides an interleaving of a first "matrix" of electromagnetic resonators, identical and having a first resonance frequency, with a second "matrix" of electromagnetic resonators, identical and having a second resonant frequency. This interlacing is obtained by the patterns that are carried by the printed circuit board of fractal or multilayer type, each pattern being centered either on a pillar or between four adjacent pillars.

L'inconvénient principal de ce type de dispositif réside dans le fait que les première et seconde fréquences de résonance ne peuvent pas être ajustées indépendamment l'une de l'autre et que les bandes de réflexion, dont ces fréquences de résonance sont les fréquences centrales, sont assez étroites. En outre, ce type de dispositif s'avère relativement encombrant.The main disadvantage of this type of device lies in the fact that the first and second resonant frequencies can not be adjusted independently of one another and that the reflection bands, whose resonance frequencies are the central frequencies , are quite narrow. In addition, this type of device is relatively bulky.

La publication scientifique « High-Impedance Electromagnetic Surfaces with Forbidden Frequency Band » de Dan SIEVENPIPER et Al. (XP011037787 ) divulgue un dispositif haute impédance réalisé avec des cavités remplies de diélectriques mais ne résout pas les inconvénients cités ci-dessus.The scientific publication Dan SIEVENPIPER and Al. High-Impedance Electromagnetic Surfaces with Forbidden Frequency Band (XP011037787) ) discloses a high impedance device made with cavities filled with dielectrics but does not solve the disadvantages mentioned above.

Résumé de l'inventionSummary of the invention

L'invention a donc notamment pour but d'améliorer la situation, et plus précisément de permettre l'obtention dans un espace réduit de fréquences (ou
longueurs d'onde) de résonance pouvant être ajustées facilement les unes par rapport aux autres et définissant les fréquences (ou longueurs d'onde) centrales de bandes de réflexion spectralement plus larges que dans l'état de la technique.The object of the invention is therefore in particular to improve the situation, and more specifically to enable obtaining in a reduced space of frequencies (or
resonant wavelengths) that can be easily adjusted relative to each other and defining the central frequencies (or wavelengths) of spectrally wider reflection bands than in the state of the art.

Elle propose notamment à cet effet un dispositif de surface à haute impédance comprenant un ensemble d'au moins deux compartiments séparés, sensiblement cylindriques, ayant des surfaces intérieures dans un matériau conducteur
conducteur électrique, et présentant chacun, à une extrémité, une unique ouverture, ces ouvertures des compartiments étant orientées d'un même côté et couvertes par au moins une structure périodique de motifs conducteurs électriques, chaque compartiment étant rempli d'un matériau diélectrique, chaque compartiment ainsi couvert formant au moins un résonateur électromagnétique, et chaque résonateur électromagnétique présentant une longueur d'onde de résonance.In particular, it proposes a high-impedance surface device comprising an assembly of at least two separate substantially cylindrical compartments having internal surfaces in a conductive material.
electrical conductor, and each having, at one end, a single opening, these openings of the compartments being oriented on the same side and covered by at least one periodic structure of electrical conductive patterns, each compartment being filled with a dielectric material, each compartment thus covered forming at least one electromagnetic resonator, and each electromagnetic resonator having a resonant wavelength.

Dans ce dispositif :

  • les compartiments sont séparés l'un de l'autre d'une distance qui est inférieure à la plus faible longueur d'onde de résonance présentée par les résonateurs qu'ils forment,
  • au moins deux longueurs d'onde de résonance respectives des résonateurs électromagnétiques, formés par ses compartiments couverts, sont différentes, et
  • la structure périodique présente une période spatiale inférieure à la moitié de la plus faible longueur d'onde de résonance.
In this device:
  • the compartments are separated from each other by a distance that is smaller than the shortest resonance wavelength presented by the resonators they form,
  • at least two respective resonance wavelengths of the electromagnetic resonators, formed by its covered compartments, are different, and
  • the periodic structure has a spatial period less than half of the lowest resonance wavelength.

Le dispositif selon l'invention peut comporter d'autres caractéristiques qui peuvent être prises séparément ou en combinaison, et notamment :

  • dans un premier mode de réalisation, il peut comprendre une cavité au sein de laquelle est agencé chaque compartiment, au moins une cloison verticale étant agencée dans cette cavité, cette cloison verticale étant conductrice électriquement et en contact avec une paroi de fond de la cavité et délimitant des compartiments, et une unique structure périodique de motifs conducteurs électriques couvrant toutes les ouvertures des compartiments ;
    • Figure imgb0001
      chaque cloison verticale peut être mobile selon une direction qui est sensiblement parallèle à un plan défini par la paroi de fond de la cavité ;
    • Figure imgb0001
      chaque compartiment peut être muni d'une paroi de fond auxiliaire conductrice électriquement, distincte de la paroi de fond de la cavité et montée mobile verticalement dans la cavité ;
    • Figure imgb0001
      il peut également comprendre des moyens de réglage agencés pour régler la hauteur de chaque cloison verticale ;
    • Figure imgb0001
      une des extrémités de chaque cloison verticale, qui s'étend en regard de l'un des motifs conducteurs électriques, peut présenter une section évasée ;
  • dans un second mode de réalisation, il peut comprendre au moins deux cavités disjointes, chaque cavité formant l'un des compartiments ;
    • Figure imgb0001
      il peut comprendre au moins deux cloisons horizontales, chaque cloison horizontale étant conductrice électriquement et montée mobile verticalement à l'intérieur de l'une des cavités, et formant une paroi de fond de l'un des compartiments ;
  • chaque compartiment peut être couvert par un seul motif conducteur électrique ;
  • chaque structure périodique de motifs conducteurs électriques peut être solidarisée à des moyens de support ;
    • Figure imgb0001
      il peut comprendre des premiers moyens de réglage agencés pour régler la permittivité diélectrique des moyens de support ;
  • il peut comprendre des seconds moyens de réglage agencés pour régler la perméabilité magnétique du matériau diélectrique.
The device according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular:
  • in a first embodiment, it may comprise a cavity in which each compartment is arranged, at least one vertical partition being arranged in this cavity, this vertical partition being electrically conductive and in contact with a bottom wall of the cavity and delimiting compartments, and a single periodic structure of electrical conductive patterns covering all openings of the compartments;
    • Figure imgb0001
      each vertical partition may be movable in a direction which is substantially parallel to a plane defined by the bottom wall of the cavity;
    • Figure imgb0001
      each compartment may be provided with an electrically conductive auxiliary bottom wall, distinct from the bottom wall of the cavity and mounted vertically movable in the cavity;
    • Figure imgb0001
      it may also comprise adjustment means arranged to adjust the height of each vertical partition;
    • Figure imgb0001
      one of the ends of each vertical partition, which extends opposite one of the electrical conductive patterns, may have a flared section;
  • in a second embodiment, it may comprise at least two disjoint cavities, each cavity forming one of the compartments;
    • Figure imgb0001
      it may comprise at least two horizontal partitions, each horizontal partition being electrically conductive and mounted vertically movable within one of the cavities, and forming a bottom wall of one of the compartments;
  • each compartment may be covered by a single electrical conductor pattern;
  • each periodic structure of electrical conductive patterns can be secured to support means;
    • Figure imgb0001
      it may comprise first adjustment means arranged to adjust the dielectric permittivity of the support means;
  • it may comprise second adjustment means arranged to adjust the magnetic permeability of the dielectric material.

L'invention propose également un récepteur de signaux de positionnement satellite, comprenant un plan de masse électrique, au moins deux éléments rayonnants disposés sur ce plan de masse, et au moins un dispositif de surface à haute impédance du type de celui présenté ci-avant, agencé sur le plan de masse entre les éléments rayonnants.The invention also proposes a satellite positioning signal receiver, comprising an electric ground plane, at least two radiating elements disposed on this ground plane, and at least one high impedance surface device of the type presented above. , arranged on the ground plane between the radiating elements.

L'invention propose également un procédé, destiné à permettre la modification de l'impédance sur plusieurs bandes de fréquences d'un dispositif de surface à haute impédance, et comprenant au moins une étape de modification de propriétés électromagnétiques d'au moins un compartiment d'un dispositif de surface à haute impédance du type de celui présenté ci-avant.The invention also proposes a method for modifying the impedance over several frequency bands of a high-impedance surface device and comprising at least one step of modifying the electromagnetic properties of at least one compartment of the device. a high impedance surface device of the type shown above.

L'invention propose également un procédé, destiné à permettre la fabrication d'un dispositif de surface à haute impédance qui comprend plusieurs compartiments séparés, sensiblement cylindriques, ainsi qu'une structure périodique de motifs conducteurs électriques.The invention also provides a method for enabling the manufacture of a high impedance surface device which comprises a plurality of substantially cylindrical, separate compartments and a periodic structure of electrical conductive patterns.

Ce procédé comprend les étapes suivantes :

  • on place dans une cavité plusieurs cloisons sensiblement planes, la cavité présentant au moins une paroi latérale et une paroi de fond conductrices électriquement, chaque cloison étant conductrice électriquement et étant en contact avec la paroi de fond ; chaque cloison définissant un plan sensiblement perpendiculaire à un plan défini par la paroi de fond, les cloisons délimitant les compartiments, les compartiments présentant chacun, à une extrémité, une unique ouverture, ces ouvertures des compartiments étant orientées d'un même côté,
  • on ajuste la hauteur de la cavité afin d'obtenir une première longueur d'onde de résonance souhaitée, associée à un premier compartiment, le premier compartiment étant délimité par la paroi latérale de la cavité et une première cloison,
  • on ajuste, à l'intérieur de la cavité, la position de chaque cloison distincte de la première cloison par rapport à cette dernière et/ou on ajuste la hauteur de chaque cloison distincte de la première cloison, afin d'obtenir des longueurs d'onde de résonance souhaitées, associées aux compartiments distincts du premier compartiment, au moins l'une de ces longueurs d'onde de résonance souhaitées étant distincte de la première longueur d'onde de résonance, chaque compartiment étant agencé de sorte que la distance qui le sépare d'un compartiment immédiatement voisin soit inférieure à la plus faible longueur d'onde de résonance parmi l'ensemble des longueurs d'onde de résonance souhaitées,
  • on remplit chaque compartiment d'un matériau diélectrique, et
  • on place la structure périodique sur la cavité afin de couvrir l'ouverture de chaque compartiment, chaque compartiment ainsi couvert formant un résonateur électromagnétique présentant une longueur d'onde de résonance ; la période spatiale de la structure périodique étant inférieure à la moitié de la plus faible longueur d'onde de résonance.
This process comprises the following steps:
  • a plurality of substantially flat partitions is placed in a cavity, the cavity having at least one electrically conductive side wall and a bottom wall, each partition being electrically conductive and in contact with the bottom wall; each partition defining a plane substantially perpendicular to a plane defined by the bottom wall, the partitions defining the compartments, the compartments each having, at one end, a single opening, these openings of the compartments being oriented on the same side,
  • the height of the cavity is adjusted to obtain a first desired resonance wavelength, associated with a first compartment, the first compartment being delimited by the lateral wall of the cavity and a first partition,
  • the position of each partition separate from the first partition relative to the latter is adjusted inside the cavity and / or the height of each partition separate from the first partition is adjusted so as to obtain lengths of resonant wave, associated with the distinct compartments of the first compartment, at least one of these desired resonant wavelengths being distinct from the first resonance wavelength, each compartment being arranged so that the distance which separates from an immediately adjacent compartment is less than the lowest resonance wavelength among all the desired resonance wavelengths,
  • each compartment is filled with a dielectric material, and
  • placing the periodic structure on the cavity to cover the opening of each compartment, each compartment thus covered forming an electromagnetic resonator having a resonance wavelength; the spatial period of the periodic structure being less than half of the lowest resonance wavelength.

Brève description des figuresBrief description of the figures

D'autres caractéristiques et avantages de l'invention apparaîtront à l'examen de la description détaillée ci-après, et des dessins annexés, sur lesquels les figures 1 à 6 illustrent de façon schématique et fonctionnelle, dans des vues en coupe, six exemples de récepteur de signaux de positionnement satellite équipé d'exemples de réalisation différents d'un dispositif de surface à haute impédance selon l'invention.Other features and advantages of the invention will appear on examining the detailed description below, and the accompanying drawings, in which the Figures 1 to 6 illustrate diagrammatically and functionally, in sectional views, six examples of satellite positioning signal receiver equipped with different embodiments of a high impedance surface device according to the invention.

Description détaillée d'un exemple de réalisationDetailed description of an example embodiment

L'invention a notamment pour but de proposer un dispositif de surface à haute impédance 1 compact, multibandes et éventuellement reconfigurable, et des procédés associés.The object of the invention is in particular to propose a compact, multi-banded and possibly reconfigurable high-impedance surface device 1 and associated methods.

Dans ce qui suit, on considère, à titre d'exemple non limitatif, que le dispositif de surface à haute impédance 1 fait partie d'un récepteur de signaux de positionnement satellite 15, éventuellement de type GNSS (de l'anglais « Global Navigation Satellite System »). Mais l'invention n'est pas limitée à cette application. Un dispositif de surface à haute impédance 1, selon l'invention, peut en effet équiper de nombreux appareils, systèmes ou installations, des domaines civil ou militaire, et notamment des véhicules terrestres, maritimes, fluviaux ou aériens, des stations émettrices et/ou réceptrices, et des bâtiments (éventuellement de type industriel).In what follows, it is considered, by way of nonlimiting example, that the high impedance surface device 1 is part of a satellite positioning signal receiver 15, possibly of the GNSS type ("Global Navigation"). Satellite System "). But the invention is not limited to this application. A high impedance surface device 1, according to the invention, can indeed equip many devices, systems or installations, civil or military, and in particular land vehicles, maritime, river or air, transmitting stations and / or receivers, and buildings (possibly of industrial type).

On a schématiquement représenté sur les figures 1 à 6, un exemple de réalisation non limitatif d'un récepteur 15 de signaux de positionnement satellite, équipé de six exemples de réalisation différents d'un dispositif de surface à haute impédance 1 selon l'invention.We have schematically represented on Figures 1 to 6 , an exemplary non-limiting embodiment of a satellite positioning signal receiver 15, equipped with six different embodiments of a high impedance surface device 1 according to the invention.

Comme illustré, ce récepteur 15 comprend un plan de masse électrique 16, au moins deux éléments rayonnants 17k disposés sur ce plan de masse 16, et au moins un dispositif de surface à haute impédance 1 selon l'invention, agencé sur le plan de masse 16 entre les éléments rayonnants 17k.As illustrated, this receiver 15 comprises a ground plane 16, at least two radiating elements 17 k disposed on this ground plane 16, and at least one high-impedance surface device 1 according to the invention, arranged on the plane of mass 16 between the radiating elements 17 k .

Par exemple, les éléments rayonnants 17k définissent un réseau adaptatif propre à recevoir des signaux de navigation, par exemple des signaux GNSS, dans un environnement brouillé en modifiant le diagramme de rayonnement du récepteur afin de générer des nuls (ou zéros) de rayonnement dans les directions des interférences de brouillage. L'adaptation du diagramme de rayonnement en fonction des brouilleurs est réalisée grâce à un post-traitement des signaux de navigation reçus sur chacun des éléments rayonnants 17k du réseau.For example, the radiating elements 17 k define an adaptive network capable of receiving navigation signals, for example GNSS signals, in a scrambled environment by modifying the radiation from the receiver to generate nulls (or zeros) of radiation in the interference interference directions. The adaptation of the radiation pattern as a function of the jammers is carried out by means of a post-processing of the navigation signals received on each of the radiating elements 17 k of the network.

On notera que dans l'exemple non limitatif illustré sur les figures 1 à 6, le récepteur 15 comprend deux éléments rayonnants 17k (k = 1 ou 2). Mais le récepteur 15 peut comprendre n'importe quel nombre d'éléments rayonnants 17k, dès lors que ce nombre est supérieur ou égal à deux. En effet, le dispositif de surface à haute impédance 1 peut notamment permettre de réduire les couplages électromagnétiques entre éléments rayonnants 17k et d'optimiser la robustesse du récepteur 15 vis-à-vis des interférences électromagnétiques.It will be noted that in the nonlimiting example illustrated on the Figures 1 to 6 the receiver 15 comprises two radiating elements 17 k (k = 1 or 2). But the receiver 15 may comprise any number of radiating elements 17 k , provided that this number is greater than or equal to two. Indeed, the high impedance surface device 1 can in particular reduce the electromagnetic coupling between radiating elements 17 k and optimize the robustness of the receiver 15 vis-à-vis electromagnetic interference.

Il est rappelé que dans un réseau adaptatif les couplages électromagnétiques inter-éléments rayonnants détériorent significativement les performances, et en particulier la capacité des algorithmes de traitement du signal à localiser précisément la position angulaire des interférences et par conséquent à générer des nuls de rayonnement dans leurs directions. Dans un tel contexte, un dispositif à surface à haute impédance 1 peut être chargé de stopper les courants qui se propagent entre les éléments rayonnants 17k du réseau adaptatif afin de réduire les couplages électromagnétiques inter-éléments rayonnants et d'optimiser la robustesse du récepteur GNSS vis-à-vis des interférences électromagnétiques.It is recalled that in an adaptive network the inter-radiating electromagnetic couplings significantly deteriorate the performances, and in particular the capacity of the signal processing algorithms to precisely locate the angular position of the interferences and consequently to generate nulls of radiation in their directions. In such a context, a high impedance surface device 1 can be responsible for stopping the currents propagating between the radiating elements 17 k of the adaptive network in order to reduce the electromagnetic coupling between radiating elements and to optimize the robustness of the receiver GNSS with regard to electromagnetic interference.

Comme illustré non limitativement sur les figures 1 à 6, un dispositif de surface à haute impédance 1, selon l'invention, comprend au moins un ensemble d'au moins deux compartiments 2j et au moins une structure périodique de motifs conducteurs électriques 4.As illustrated without limitation on Figures 1 to 6 a high impedance surface device 1 according to the invention comprises at least one set of at least two compartments 2 j and at least one periodic structure of electrical conductive patterns 4.

Les compartiments 2j de l'ensemble sont séparés et sensiblement cylindriques, ont des surfaces intérieures réalisées dans un matériau conducteur électrique, et présentent chacun, à une extrémité, une unique ouverture 3. De plus, chaque compartiment 2j est rempli d'un matériau diélectrique, par exemple de l'air. Par exemple, les compartiments 2j sont sensiblement cylindriques de section rectangulaire ou carrée.The compartments 2 j of the assembly are separated and substantially cylindrical, have internal surfaces made of an electrically conductive material, and each have, at one end, a single opening 3. In addition, each compartment 2 j is filled with a dielectric material, for example air. For example, the compartments 2 j are substantially cylindrical of rectangular or square section.

Les ouvertures 3 des compartiments 2j sont toutes orientées d'un même côté et couvertes par au moins une structure périodique de motifs conducteurs électriques 4. On comprendra que chaque ouverture 3 peut être associée à sa propre structure périodique de motifs conducteurs électriques 4, comme illustré non limitativement sur les figures 5 et 6, ou bien les ouvertures 3 peuvent être associées à une même structure périodique de motifs conducteurs électriques 4, comme illustré non limitativement sur les figures 1 à 4.The openings 3 of the compartments 2 j are all oriented on the same side and covered by at least one periodic structure of electrical conductive patterns 4. It will be understood that each opening 3 can be associated with its own periodic structure of electrical conductive patterns 4, such as illustrated without limitation on Figures 5 and 6 or the openings 3 may be associated with the same periodic structure of electrical conductive patterns 4, as shown in non-limiting manner on the Figures 1 to 4 .

On notera que chaque compartiment 2j peut être couvert par un seul motif conducteur électrique 4.It will be noted that each compartment 2 j can be covered by a single electrical conductive pattern 4.

On notera également que, les motifs conducteurs électriques 4 de chaque structure périodique peuvent être solidarisés à des moyens de support, comme par exemple une carte à circuits imprimés (ou PCB (de l'anglais « Printed Circuit Board »)) 18, de type monocouche ou multicouches. Par exemple, les motifs conducteurs électriques 4 peuvent être imprimés sur cette carte à circuits imprimés 18. Les motifs conducteurs électriques 4 sont agencés périodiquement et leurs taille et périodicité sont petites devant la longueur d'onde utilisée.It will also be noted that the electrical conductive patterns 4 of each periodic structure may be secured to support means, such as for example a printed circuit board (or PCB), 18 of type monolayer or multilayer. For example, the electrical conductive patterns 4 can be printed on this printed circuit board 18. The electrical conductive patterns 4 are arranged periodically and their size and periodicity are small compared to the wavelength used.

En variante non représentée, chaque motif 4 peut être une grille métallique assurant sa propre fonction de support.In variant not shown, each pattern 4 may be a metal gate ensuring its own support function.

On notera également que des éléments actifs, tels que par exemple des varactors, peuvent être éventuellement et préalablement intégrés sur/dans la carte à circuits imprimés 18 pour ajuster l'effet capacitif des motifs 4.It will also be noted that active elements, such as, for example, varactors, may be optionally and previously integrated on / in the printed circuit board 18 to adjust the capacitive effect of the patterns 4.

On notera également que le dispositif 1 peut éventuellement comprendre des premiers moyens de réglage agencés pour régler la permittivité diélectrique des moyens de support. Les premiers moyens de réglage peuvent être réalisés sous la forme de matériaux dont les propriétés peuvent être commandées électroniquement, tels que par exemple des cristaux liquides, des plasmas ou encore des matériaux ferroélectriques, et de moyens de commande électronique de tels matériaux. En variante, les premiers moyens de réglage peuvent être réalisés sous la forme d'un métamatériau de permittivité ajustable. La permittivité diélectrique agit sur l'inductance du compartiment 2j. Plus la permittivité est grande et plus la hauteur du compartiment 2j peut être faible.It will also be noted that the device 1 may optionally comprise first adjustment means arranged to adjust the dielectric permittivity of the support means. The first adjustment means can be made in the form of materials whose properties can be controlled electronically, such as for example liquid crystals, plasmas or ferroelectric materials, and electronic control means of such materials. As a variant, the first adjustment means may be made in the form of an adjustable permittivity metamaterial. The dielectric permittivity acts on the inductance of compartment 2 j . The higher the permittivity, the lower the height of compartment 2 j can be.

Chaque compartiment 2j forme avec la structure périodique de motifs conducteurs électriques 4 qui couvre son ouverture 3 au moins un résonateur électromagnétique présentant une fréquence de résonance.Each compartment 2 j forms with the periodic structure of electrical conductive patterns 4 which covers its opening 3 at least one electromagnetic resonator having a resonant frequency.

On notera en outre que plus un compartiment 2j est large, plus la taille de la boucle de courant qui est à l'intérieur est grande, et donc plus l'inductance est grande.Note further that the larger a compartment 2j, the larger the size of the current loop that is inside, and therefore the greater the inductance.

Les compartiments 2j sont séparés l'un de l'autre d'une distance qui est inférieure à la plus faible longueur d'onde de résonance présentée par les résonateurs électromagnétiques qu'ils forment. Par ailleurs, au moins deux longueurs d'onde de résonance respectives des résonateurs électromagnétiques formés par les compartiments 2j couverts sont différentes. De plus, la structure périodique de motifs conducteurs électriques 4 présente une période spatiale qui est inférieure à la moitié de la plus faible longueur d'onde de résonance.The compartments 2 j are separated from each other by a distance that is smaller than the shortest resonance wavelength presented by the electromagnetic resonators they form. Furthermore, at least two respective resonant wavelengths of electromagnetic resonators formed by the compartments 2 covered j are different. In addition, the periodic structure of electrical conductive patterns 4 has a spatial period that is less than half of the lowest resonance wavelength.

Le dispositif 1 produit un effet haute impédance à plusieurs fréquences (ou longueurs d'onde) de résonance. Le nombre de fréquences (ou longueurs d'onde) de résonance exploitables est égal au nombre de compartiments. L'effet haute impédance est produit sur une surface fictive qui se situe au-dessus de la carte à circuits imprimés 18, très proche et parallèle à la carte à circuits imprimés 18 et pouvant couvrir une surface plus ou moins grande en fonction de la fréquence (ou longueur d'onde) de résonance considérée.The device 1 produces a high impedance effect at several frequencies (or wavelengths) of resonance. The number of exploitable resonance frequencies (or wavelengths) is equal to the number of compartments. The high impedance effect is produced on a fictitious surface which is located above the printed circuit board 18, very close and parallel to the printed circuit board 18 and can cover a larger or smaller surface depending on the frequency (or wavelength) of resonance considered.

Le dispositif 1 peut être réalisé selon des exemples de réalisation qui peuvent être regroupés au sein d'au moins deux familles. Une première famille regroupe les exemples illustrés sur les figures 1 à 4. Une seconde famille regroupe les exemples illustrés sur les figures 5 et 6.The device 1 can be implemented according to exemplary embodiments which can be grouped together in at least two families. A first family groups the illustrated examples on the Figures 1 to 4 . A second family includes the illustrated examples on the Figures 5 and 6 .

Pour tous les exemples de la première famille, le dispositif 1 comprend une unique cavité 5 au sein de laquelle est agencé (ou défini) chaque compartiment 2j. Pour ce faire, la cavité 5 comprend au moins une cloison verticale 6 qui est conductrice électriquement et en contact avec une paroi de fond 7 et qui délimite deux compartiments 2j. Chaque cloison verticale 6 est de préférence sensiblement plane, et définit un plan sensiblement perpendiculaire à un plan défini par la paroi de fond 7 de la cavité 5. Ce caractère conducteur électrique peut provenir du matériau dans lequel est réalisée la cloison verticale 6 ou du fait que la cloison verticale 6 est revêtue sur ses surfaces d'une couche d'un matériau conducteur électrique. Par ailleurs, une unique structure périodique de motifs conducteurs électriques 4 couvre toutes les ouvertures 3 des différents compartiments 2j.For all the examples of the first family, the device 1 comprises a single cavity 5 in which each compartment 2 j is arranged (or defined). To do this, the cavity 5 comprises at least one vertical partition 6 which is electrically conductive and in contact with a bottom wall 7 and which delimits two compartments 2 j . Each vertical partition 6 is preferably substantially plane, and defines a plane substantially perpendicular to a plane defined by the bottom wall 7 of the cavity 5. This electrical conductive character can come from the material in which the vertical partition 6 is made or the fact that the vertical partition 6 is coated on its surfaces with a layer of an electrically conductive material. Furthermore, a single periodic structure of electrical conductive patterns 4 covers all the openings 3 of the different compartments 2 j .

La cavité 5 est délimitée par au moins une paroi latérale 10 et la paroi de fond 7. Ces dernières parois 7, 10 sont conductrices électriquement. Ce caractère conducteur électrique peut provenir du matériau dans lequel elles sont réalisées ou du fait qu'elles sont revêtues d'une couche d'un matériau conducteur électrique sur leurs surfaces intérieures.The cavity 5 is delimited by at least one side wall 10 and the bottom wall 7. The latter walls 7, 10 are electrically conductive. This electrically conductive character can come from the material in which they are made or because they are coated with a layer of an electrically conductive material on their inner surfaces.

On notera que la cavité 5 peut soit être rapportée et solidarisée au plan de masse 16, par exemple par soudage ou collage, soit faire partie intégrante du plan de masse 16, par exemple par emboutissage et découpe.It will be noted that the cavity 5 can either be attached and secured to the ground plane 16, for example by welding or gluing, or be an integral part of the ground plane 16, for example by stamping and cutting.

Dans les exemples non limitatifs illustrés sur les figures 1, 2 et 4, la cavité 5 comprend quatre compartiments 21 à 24 (j = 1 à 4), séparés les uns des autres par trois cloisons verticales 6.In the non-limiting examples illustrated on the Figures 1, 2 and 4 , the cavity 5 comprises four compartments 2 1 to 2 4 (j = 1 to 4), separated from each other by three vertical partitions 6.

Dans l'exemple non limitatif illustré sur la figure 3, la cavité 5 comprend trois compartiments 21 à 23 (j = 1 à 3), séparés les uns des autres par deux cloisons verticales 6.In the non-limiting example illustrated on the figure 3 , the cavity 5 comprises three compartments 2 1 to 2 3 (j = 1 to 3), separated from each other by two vertical partitions 6.

On notera que la cavité 5 peut comprendre n'importe quel nombre de compartiments 2j, dès lors que ce nombre est supérieur ou égal à deux.It will be noted that the cavity 5 can comprise any number of compartments 2 j , provided that this number is greater than or equal to two.

Cette cavité 5 à résonateurs électromagnétiques multiples produit des effets capacitifs et inductifs ei qui sont à l'origine de la haute impédance de surface. Il existe notamment un effet capacitif entre le plan de masse 16 et chaque motif 4 qui la chevauche, un effet capacitif entre motifs 4 qui se chevauchent, et un effet inductif ei dans chaque compartiment 2j, plus précisément dans la profondeur hj de chaque compartiment 2j, formant ainsi une boucle de courant.This cavity 5 with multiple electromagnetic resonators produces capacitive and inductive effects ei which are at the origin of the high surface impedance. There is in particular a capacitive effect between the ground plane 16 and each pattern 4 which overlaps it, a capacitive effect between overlapping patterns 4, and an inductive effect ei in each compartment 2 j , more precisely in the depth hj of each compartment. 2 j , thus forming a current loop.

La présence de cloison(s) verticale(s) 6 conductrices induit également des effets capacitifs et inductifs additionnels. En particulier, des effets capacitifs additionnels sont présents entre les extrémités « supérieures » 11 des cloisons verticales 6 et les motifs 4 qui les chevauchent. Ces effets capacitifs additionnels sont d'autant plus importants que les distances qui les séparent sont petites. Des effets inductifs additionnels sont produits par les multiples boucles de courant qui sont présentes dans les différents compartiments 2j.The presence of vertical partition (s) 6 conductors also induces additional capacitive and inductive effects. In particular, additional capacitive effects are present between the "upper" ends 11 of the vertical partitions 6 and the patterns 4 which overlap them. These additional capacitive effects are all the more important as the distances between them are small. Additional inductive effects are produced by the multiple current loops that are present in the different compartments 2 j .

Dans cette première famille, pour la première fréquence de résonance f1 associée au premier compartiment 21, l'effet haute impédance est localisé dans la zone qui s'étend sur la totalité de la cavité 5, tandis que pour les autres fréquences de résonance f2, f3,...,fn, associées respectivement aux autres compartiments 22, 23,..., 2n, l'effet haute impédance est localisé soit sur la totalité de la cavité 5, soit dans une zone plus restreinte comme au-dessus d'un compartiment 2j (j = 2 à n), selon les positions horizontales respectives des cloisons verticales 6.In this first family, for the first resonance frequency f1 associated with the first compartment 2 1 , the high impedance effect is located in the area that extends over the entire cavity 5, while for the other resonance frequencies f2 , f3, ..., fn, respectively associated with the other compartments 2 2 , 2 3 , ..., 2 n , the high impedance effect is located either on the whole of the cavity 5, or in a smaller area such as above a compartment 2 j (j = 2 to n), according to the respective horizontal positions of the vertical partitions 6.

La valeur des fréquences de résonance dépend des effets capacitifs et inductifs obtenus dans le dispositif 5. Par conséquent, le choix des fréquences de résonance peut notamment se faire en ajustant les distances lm (ici m = 1 à 3 ou 1 à 2) respectives qui séparent les cloisons verticales 6 de la paroi latérale 10 et/ou les hauteurs hm respectives des cloisons verticales 6 autrement dit les distances verticales entre les extrémités supérieures 11 des cloisons verticales 6 et les motifs 4 qui les chevauchent. Les distances verticales entre les extrémités supérieures 11 des cloisons verticales 6 et les motifs 4 peuvent être nulles, les cloisons verticales 6 étant dans ce cas en contact avec la carte à circuits imprimés 18.The value of the resonant frequencies depends on the capacitive and inductive effects obtained in the device 5. Consequently, the choice of the resonant frequencies can in particular be done by adjusting the distances lm (here m = 1 to 3 or 1 to 2) respectively which separating the vertical partitions 6 from the side wall 10 and / or the respective heights hm of the vertical partitions 6, in other words the vertical distances between the upper ends 11 of the vertical partitions 6 and the patterns 4 which overlap them. The vertical distances between the upper ends 11 of the vertical partitions 6 and the patterns 4 may be zero, the vertical partitions 6 being in this case in contact with the printed circuit board 18.

On notera que le réglage des fréquences de résonance peut s'effectuer en ajustant à la fois les distances lm et les hauteurs hm. Cette solution est notamment avantageuse lorsque l'on souhaite obtenir plus de deux fréquences de résonance car elle permet d'augmenter les degrés de liberté pour optimiser le dispositif 1.It should be noted that the resonance frequency setting can be made by adjusting both the distances lm and the heights hm. This solution is particularly advantageous when it is desired to obtain more than two resonance frequencies because it makes it possible to increase the degrees of freedom to optimize the device 1.

Le choix des fréquences de résonance par ajustement des distances lm respectives séparant les cloisons verticales 6 de la paroi latérale 10 est illustré sur les figures 1, 2 et 4. Le choix des fréquences de résonance par ajustement des hauteurs hm respectives des cloisons verticales 6 est illustré sur la figure 2.The choice of the resonant frequencies by adjustment of the respective distances lm separating the vertical partitions 6 from the side wall 10 is illustrated in FIGS. Figures 1, 2 and 4 . The choice of resonance frequencies by adjustment of the respective height hm of the vertical partitions 6 is illustrated on the figure 2 .

Le choix des fréquences de résonance peut faire l'objet soit d'une conception initiale ou d'un réglage préalable, par exemple via des moyens de réglages appropriés pour des fonctions données, soit d'un réglage en temps réel au moyen de moyens de réglages appropriés.The choice of the resonant frequencies may be the subject of an initial design or of a preliminary adjustment, for example via appropriate adjustment means for given functions, or of a real-time adjustment by means of appropriate settings.

Pour permettre un réglage des distances lm et donc des positions horizontales des cloisons verticales 6, chaque cloison verticale 6 peut être mobile selon une direction qui est sensiblement parallèle à un plan défini par la paroi de fond 7 de la cavité 5. Dans ce cas, le dispositif 1 peut comprendre des moyens de réglage agencés pour régler la position horizontale de chaque cloison verticale 6 dans la cavité 5.To allow an adjustment of the distances lm and thus the horizontal positions of the vertical partitions 6, each vertical partition 6 can be movable in a direction which is substantially parallel to a plane defined by the bottom wall 7 of the cavity 5. In this case, the device 1 may comprise adjustment means arranged to adjust the horizontal position of each vertical partition 6 in the cavity 5.

Pour permettre un réglage des hauteurs hm, chaque cloison verticale 6 peut être mobile selon une direction (ici verticale) qui est sensiblement perpendiculaire au plan défini par la paroi de fond 7 de la cavité 5. Dans ce cas, le dispositif 1 peut comprendre des moyens de réglage agencés pour régler la hauteur de chaque cloison verticale 6 dans la cavité 5.To allow a height adjustment hm, each vertical partition 6 can be movable in a direction (here vertical) which is substantially perpendicular to the plane defined by the bottom wall 7 of the cavity 5. In this case, the device 1 may comprise adjusting means arranged to adjust the height of each vertical partition 6 in the cavity 5.

En variante, et comme illustré sur la figure 3, chaque compartiment 2j peut être muni d'une paroi de fond auxiliaire 8, distincte de la paroi de fond 7 de la cavité 5, conductrice électriquement, et montée mobile verticalement dans la cavité 5. On comprendra qu'en faisant varier la position (ici verticale) hm d'une paroi de fond auxiliaire 8 d'un compartiment 2j, cela revient à faire varier la hauteur dans la cavité 5 de la cloison verticale 6 correspondante. Dans ce cas, le dispositif 1 peut comprendre des moyens de réglage agencés pour régler la position (ici verticale) de chaque paroi de fond auxiliaire 8 au sein de son compartiment 2j.Alternatively, and as illustrated on the figure 3 each compartment 2 j can be provided with an auxiliary bottom wall 8, distinct from the bottom wall 7 of the cavity 5, electrically conductive, and mounted vertically movable in the cavity 5. It will be understood that by varying the position (here vertical) hm of an auxiliary bottom wall 8 of a compartment 2 j , this amounts to varying the height in the cavity 5 of the corresponding vertical partition 6. In this case, the device 1 may comprise adjustment means arranged to adjust the position (here vertical) of each auxiliary bottom wall 8 in its compartment 2 j .

On notera, comme illustré non limitativement sur la figure 4, que l'extrémité 11 de chaque cloison verticale 6 qui s'étend en regard de l'un des motifs conducteurs électriques 4 peut éventuellement présenter une section évasée. Cela permet en effet d'augmenter l'effet capacitif entre la cloison verticale 6 et les motifs 4 de la carte à circuits imprimés 18.It will be noted, as illustrated without limitation on the figure 4 , that the end 11 of each vertical partition 6 which extends opposite one of the electrical conductive patterns 4 may optionally have a flared section. This makes it possible to increase the capacitive effect between the vertical partition 6 and the patterns 4 of the printed circuit board 18.

A titre d'exemple, pour régler les fréquences de résonance sur les bandes souhaitées, on peut mettre en oeuvre le procédé suivant. Tout d'abord, on peut concevoir un premier résonateur électromagnétique mono-bande sur une fréquence f1. Ensuite, on peut déterminer le nombre de cloisons verticales 6 pour fixer le nombre de fréquences de résonance f1 à fn. Puis, on peut insérer les cloisons verticales 6 dans la cavité 5. On peut ensuite ajuster la hauteur de la cavité 5 pour obtenir la première fréquence de résonance à la fréquence f1. Enfin, on peut ajuster les distances lm et/ou les hauteurs hm pour régler les fréquences f2 à fn des autres fréquences de résonance.By way of example, to set the resonance frequencies on the desired bands, the following method can be implemented. First, we can design a first single-band electromagnetic resonator on a frequency f1. Then, we can determine the number of vertical partitions 6 to set the number of resonance frequencies f1 to fn. Then, the vertical partitions 6 can be inserted into the cavity 5. The height of the cavity 5 can then be adjusted to obtain the first resonance frequency at the frequency f1. Finally, it is possible to adjust the distances lm and / or the heights hm to adjust the frequencies f2 to fn of the other resonant frequencies.

En d'autres termes, on propose un procédé, destiné à permettre la modification de l'impédance sur plusieurs bandes de fréquences d'un dispositif 1, et comprenant au moins une étape de modification de propriétés électromagnétiques d'au moins un compartiment 2j de ce dispositif 1.In other words, there is provided a method for enabling impedance changes on multiple frequency bands of a device 1, and comprising at least one electromagnetic property modifying step of at least one compartment 2 j of this device 1.

Dans une variante, un procédé peut être destiné à permettre la fabrication d'un dispositif de surface à haute impédance 1 qui comprend plusieurs compartiments séparés 2j, sensiblement cylindriques, ainsi qu'une structure périodique de motifs conducteurs électriques 4.Alternatively, a method may be designed to allow the manufacture of a high impedance surface of device 1 which comprises a plurality of separate compartments 2 j, substantially cylindrical, and a periodic structure patterns electrical conductors 4.

Cette variante de procédé comprend les étapes suivantes :

  • on place dans une cavité 5 plusieurs cloisons 6 sensiblement planes, la cavité 5 présentant au moins une paroi latérale 10 et une paroi de fond 7 conductrices électriquement, chaque cloison 6 étant conductrice électriquement et étant en contact avec la paroi de fond 7; chaque cloison 6 définissant un plan sensiblement perpendiculaire à un plan défini par la paroi de fond 7, les cloisons 6 délimitant les compartiments 2j, les compartiments 2j présentant chacun, à une extrémité, une unique ouverture 3, ces ouvertures 3 des compartiments 2j étant orientées d'un même côté,
  • on ajuste la hauteur hc de la cavité 5 afin d'obtenir une première longueur d'onde de résonance souhaitée, associée à un premier compartiment 21, le premier compartiment 21 étant délimité par la paroi latérale 10 de la cavité 5 et une première cloison 6,
  • on ajuste, à l'intérieur de la cavité 5, la position de chaque cloison 6 distincte de la première cloison par rapport à cette dernière et/ou on ajuste la hauteur de chaque cloison 6 distincte de la première cloison, afin d'obtenir des longueurs d'onde de résonance souhaitées, associées aux compartiments 2j distincts du premier compartiment 21, au moins l'une de ces longueurs d'onde de résonance souhaitées étant distincte de la première longueur d'onde de résonance, chaque compartiment 2j étant agencé de sorte que la distance qui le sépare d'un compartiment 2j immédiatement voisin soit inférieure à la plus faible longueur d'onde de résonance parmi l'ensemble des longueurs d'onde de résonance souhaitées,
  • on remplit chaque compartiment 2j d'un matériau diélectrique, et
  • on place la structure périodique sur la cavité 5 afin de couvrir l'ouverture 3 de chaque compartiment 2j, chaque compartiment ainsi couvert formant un résonateur électromagnétique présentant une longueur d'onde de résonance ; la période spatiale de la structure périodique étant inférieure à la moitié de la plus faible longueur d'onde de résonance.
This process variant comprises the following steps:
  • a plurality of substantially planar partitions 6 are placed in a cavity 5, the cavity 5 having at least one electrically conductive side wall 10 and a bottom wall 7, each partition 6 being electrically conductive and in contact with the bottom wall 7; each partition 6 defining a plane substantially perpendicular to a plane defined by the bottom wall 7, the partitions 6 delimiting the compartments 2 j , the compartments 2 j each having, at one end, a single opening 3, these openings 3 of the compartments 2 j being oriented on the same side,
  • the height hc of the cavity 5 is adjusted in order to obtain a first desired resonance wavelength, associated with a first compartment 2 1 , the first compartment 2 1 being delimited by the side wall 10 of the cavity 5 and a first partition 6,
  • inside the cavity 5 is adjusted the position of each partition 6 distinct from the first partition with respect to the latter and / or the height is adjusted of each partition 6 distinct from the first partition, in order to obtain desired resonance wavelengths, associated with compartments 2 j distinct from the first compartment 2 1 , at least one of these desired resonance wavelengths being distinct from the first resonance wavelength, each compartment 2 j being arranged so that the distance between the compartment 2 day immediately adjacent is less than the lowest resonance wavelength from among all the desired resonance wavelengths,
  • filling each compartment 2 j of a dielectric material, and
  • placing the periodic structure on the cavity 5 to cover the opening 3 of each compartment 2 j , each well covered compartment forming an electromagnetic resonator having a resonant wavelength; the spatial period of the periodic structure being less than half of the lowest resonance wavelength.

On notera que, de manière surprenante, la variation de la largeur du premier compartiment 21, et donc la variation de la distance l1, ne fait quasiment pas varier la première fréquence de résonance f1 mais fait varier la deuxième fréquence de résonance f2.It will be noted that, surprisingly, the variation of the width of the first compartment 2 1 , and therefore the variation of the distance 11, does not substantially change the first resonance frequency f1 but varies the second resonant frequency f2.

Une analyse modale permet de comprendre l'effet inattendu résultant de l'invention. En effet, la fréquence de résonance f1 reste stable en fonction de la distance l1 car le mode généré dans le dispositif 1 est issu d'une résonance où le champ magnétique se déplace verticalement dans la cavité 5 de façon équiphase. Ce mode de résonance est celui qui est observé lorsque la première cloison verticale 6 n'est pas présente dans la cavité 5 (cas où l1 = 0). De par la nature de ce mode de résonance, la variation de la distance l1 n'affecte en rien la fréquence de résonance f1. A l'inverse, le champ magnétique dans le dispositif 1 à la fréquence de résonance f2 a une cartographie différente. La cloison verticale 6 interagit en effet avec le champ électromagnétique, et donc le champ s'annule sur une ligne verticale au voisinage de la cloison verticale 6 et produit un mode d'ordre supérieur à celui observé à la fréquence de résonance f1. La distance l1 conditionne donc ce mode de résonance et affecte la valeur de la fréquence de résonance f2.Modal analysis makes it possible to understand the unexpected effect resulting from the invention. Indeed, the resonant frequency f1 remains stable as a function of the distance 11, since the mode generated in the device 1 is the result of a resonance where the magnetic field moves vertically in the cavity 5 in an electromagnetic manner. This resonance mode is the one observed when the first vertical partition 6 is not present in the cavity 5 (in which case l1 = 0). Due to the nature of this resonance mode, the variation of the distance 11 does not affect the resonance frequency f1. Conversely, the magnetic field in the device 1 at the resonance frequency f2 has a different mapping. The vertical partition 6 in fact interacts with the electromagnetic field, and thus the field vanishes on a vertical line in the vicinity of the vertical partition 6 and produces a higher order mode than that observed at the resonance frequency f1. The distance 11 thus conditions this resonance mode and affects the value of the resonant frequency f2.

Pour tous les exemples de la seconde famille, le dispositif 1 comprend au moins deux cavités 5j disjointes formant (ou définissant) chacune l'un des compartiments 2j. Le nombre de fréquences (ou longueurs d'onde) de résonance est donc ici défini par le nombre de cavités 5j.For all the examples of the second family, the device 1 comprises at least two cavities 5 j disjoint forming (or defining) each one of the compartments 2 j. The number of frequencies (or wavelengths) of resonance is here defined by the number of cavities 5 j .

Dans les exemples illustrés non limitativement sur les figures 5 et 6, chaque cavité 5j est associée à sa propre structure périodique de motifs conducteurs électriques 4 qui est définie sur sa propre carte à circuits imprimés 18. Mais dans une variante de réalisation non illustrée, chaque cavité 5j est associée à sa propre structure périodique de motifs conducteurs électriques 4, mais les différentes structures périodiques sont définies sur une même carte à circuits imprimés 18.In the examples illustrated without limitation on the Figures 5 and 6 each cavity 5j is associated with its own periodic pattern of electrical conductive patterns 4 which is defined on its own printed circuit board 18. But in a non-illustrated embodiment, each cavity 5j is associated with its own periodic structure of electrical conductive patterns 4, but the various periodic structures are defined on the same printed circuit board 18.

Les cavités 5j, et donc les résonateurs électromagnétiques, partagent un même plan de masse 16 et, comme indiqué plus haut, sont espacé(e)s les un(e)s des autres d'une distance qui est inférieure à la plus faible longueur d'onde de résonance.The cavities 5 j , and therefore the electromagnetic resonators, share the same ground plane 16 and, as indicated above, are spaced apart from one another by a distance that is less than the smallest. resonance wavelength.

Cette famille d'exemples de réalisation a la particularité de produire des effets à haute impédance successifs pour des fréquences de résonance distinctes. Chaque résonateur électromagnétique est caractérisé par sa propre fréquence de résonance. L'effet haute impédance est produit sur une surface fictive se situant au-dessus de la ou chaque carte à circuits imprimés 18 et très proche de, et parallèle à, la ou chaque carte à circuits imprimés 18.This family of exemplary embodiments has the particularity of producing successive high impedance effects for distinct resonant frequencies. Each electromagnetic resonator is characterized by its own resonance frequency. The high impedance effect is produced on a dummy surface located above the or each printed circuit board 18 and very close to, and parallel to, the or each printed circuit board 18.

Pour chaque résonateur électromagnétique, la fréquence de résonance dépend principalement de la hauteur hm (ici m = j) de la cavité 5j associée, du matériau diélectrique remplissant cette cavité 5j, et des caractéristiques de transmission et de réflexion de la carte à circuits imprimés 18. En effet, dans une représentation de type « circuit LC », la hauteur hm d'une cavité 5j et le type de matériau diélectrique dans la cavité 5j impactent directement la valeur d'inductance, alors que la carte à circuits imprimés 18 a tendance à impacter la valeur de la capacité.For each electromagnetic resonator, the resonance frequency depends mainly on the height hm (here m = j) of the associated cavity 5 j , the dielectric material filling this cavity 5 j , and the transmission and reflection characteristics of the circuit board In fact, in an "LC circuit" type representation, the height hm of a cavity 5 j and the type of dielectric material in the cavity 5 j directly impact the inductance value, whereas the circuit board printed matter 18 tends to impact the value of the capacity.

Le caractère multi-résonant obtenu également avec cette famille d'exemples de réalisation s'avère inattendu, dans la mesure où il était logique de penser que les fréquences supérieures à la fréquence de résonance de la première cavité 51 ne pouvaient pas traverser cette dernière cavité 51 et atteindre les cavités voisines 5j (avec j ≠ 1).The multi-resonant character obtained also with this family of exemplary embodiments proves unexpected, insofar as it was logical to think that the frequencies higher than the resonance frequency of the first cavity 5 1 could not cross the latter cavity 5 1 and reach the neighboring cavities 5 j (with j ≠ 1).

On notera, comme illustré non limitativement sur la figure 6, que le dispositif 1 peut comprendre au moins deux cloisons horizontales 9j conductrices électriquement, montées chacune mobile verticalement à l'intérieur de l'une des cavités 5j, et formant chacune une paroi de fond de l'un des compartiments 2j. Le caractère conducteur électrique peut provenir du matériau dans lequel est réalisée chaque cloison horizontale 9j ou du fait que chaque cloison horizontale 9j est revêtue, sur ses surfaces, d'une couche d'un matériau conducteur électrique.It will be noted, as illustrated without limitation on the figure 6 , That the device 1 can comprise at least two horizontal partitions 9 j electrically conductive, each mounted vertically movable within one of the cavities 5 j, and each forming a bottom wall of one of the compartments 2 j. The electrical conductive character can come from the material in which is made each horizontal partition 9 j or the fact that each horizontal partition 9 j is coated on its surfaces with a layer of an electrically conductive material.

Cette option requiert que le dispositif 1 comprenne des moyens de réglage agencés pour régler la position (ici verticale) de chaque cloison horizontale 9j au sein de sa cavité 5j, et donc de son compartiment 2j.This option requires that the device 1 comprises adjustment means arranged to adjust the position (here vertical) of each horizontal partition 9 j in its cavity 5 j , and therefore its compartment 2 j .

On notera également que le dispositif 1 peut éventuellement comprendre des seconds moyens de réglage agencés pour régler la perméabilité magnétique du matériau remplissant chaque compartiment 2j. Les seconds moyens de réglage peuvent être réalisés sous la forme d'un matériau magnétique de perméabilité magnétique ajustable, tel que par exemple un matériau ferromagnétique ou un métamatériau. A titre d'exemple non limitatif, les seconds moyens de réglage peuvent être réalisés sous la forme d'une ferrite dont la perméabilité magnétique change sous l'influence d'un champ magnétique. La bande de réflexion augmente en effet avec l'augmentation de la perméabilité magnétique du matériau. Une perméabilité magnétique ajustable permet d'ajuster l'inductance.Note also that the device 1 may optionally comprise second adjustment means arranged to adjust the magnetic permeability of the material filling each compartment 2 j . The second adjustment means may be made in the form of a magnetic material of adjustable magnetic permeability, such as for example a ferromagnetic material or a metamaterial. By way of nonlimiting example, the second adjustment means can be made in the form of a ferrite whose magnetic permeability changes under the influence of a magnetic field. The reflective band increases with the increase of the magnetic permeability of the material. An adjustable magnetic permeability makes it possible to adjust the inductance.

Grâce à l'invention, on dispose d'un dispositif de surface à haute impédance compact car comprenant un nombre de cavités réduit. On dispose en outre d'un dispositif de surface à haute impédance multibandes, éventuellement reconfigurable, et adapté à des bandes de réflexion spectralement plus larges que dans l'état de la technique.Thanks to the invention, a compact high-impedance surface device is available because it comprises a reduced number of cavities. In addition, a multi-band high-impedance surface device is available, possibly reconfigurable, and adapted to spectrally wider reflection bands than in the state of the art.

Claims (14)

  1. High-impedance surface device (1) comprising a set of at least two separate compartments (2j), which are substantially cylindrical, having internal surfaces in an electrically conductive material, and each having, at one end, a single aperture (3), said apertures (3) of the compartments (2j) being oriented on one and the same side and covered by at least one periodic structure of electrically conductive patterns (4), each compartment (2j) being filled with a dielectric material, each compartment (2j) thus covered forming at least one electromagnetic resonator, and each electromagnetic resonator exhibiting a resonant wavelength, said device (1) being characterized in that:
    - said at least two compartments (2j) are separated from one another by a distance less than the shortest resonant wavelength exhibited by said resonators that they form,
    - at least two respective resonant wavelengths of said electromagnetic resonators formed by said at least two covered compartments (2j) are different, and
    - said periodic structure exhibits a spatial period less than half said shortest resonant wavelength.
  2. Device according to Claim 1, characterized in that it comprises a cavity (5) within which each compartment (2j) is arranged, at least one vertical partition (6) arranged in said cavity (5), said vertical partition (6) being electrically conductive, in contact with a bottom wall (7) of said electrically conductive cavity (5), and delimiting said at least two compartments (2j), and a single periodic structure of electrically conductive patterns (4) covering all said apertures (3) of said compartments (2j).
  3. Device according to Claim 2, characterized in that each vertical partition (6) is mobile in a direction substantially parallel to a plane defined by said bottom wall (7) of said cavity (5).
  4. Device according to Claim 2 or 3, characterized in that each compartment (2j) is provided with an auxiliary electrically conductive bottom wall (8), distinct from said bottom wall (7) of the cavity (5) and mounted to be vertically mobile in said cavity (5).
  5. Device according to one of Claims 2 to 4, characterized in that it comprises setting means arranged to set the height of each vertical partition (6).
  6. Device according to one of Claims 2 to 5, characterized in that one of the ends of each vertical partition (6) extends facing one of the electrically conductive patterns (4) and has a flared section.
  7. Device according to Claim 1, characterized in that it comprises at least two unconnected cavities (5j), each cavity (5j) forming one of said compartments (2j).
  8. Device according to Claim 7, characterized in that it comprises at least two horizontal partitions (9), each horizontal partition (9) being electrically conductive and mounted to be vertically mobile inside one of said cavities (5j), and forming a bottom wall of one of said compartments (2j).
  9. Device according to one of the preceding claims, characterized in that each compartment (2j) is covered by a single electrically conductive pattern (4).
  10. Device according to one of the preceding claims, characterized in that each periodic structure of electrically conductive patterns (4) is secured to support means (18).
  11. Device according to Claim 10, characterized in that it comprises first setting means arranged to set the dielectric permittivity of said support means.
  12. Device according to one of the preceding claims, characterized in that it comprises second setting means arranged to set the magnetic permeability of said dielectric material.
  13. Satellite positioning signal receiver (15), comprising an electric ground plane (16), and at least two radiant elements (17k) arranged on said ground plane (16), characterized in that it also comprises at least one high-impedance surface device (1) according to one of the preceding claims, arranged on said ground plane (16) between said radiant elements (17k).
  14. Method for modifying the impedance over several frequency bands of a high-impedance surface device, characterized in that it comprises at least one step of modifying electromagnetic properties of at least one compartment (2j) of a high-impedance surface device (1) according to one of Claims 1 to 12.
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IL252085A0 (en) 2017-07-31
FR3029694B1 (en) 2016-12-09
CA2967732C (en) 2022-12-13
FR3029694A1 (en) 2016-06-10
US20170365931A1 (en) 2017-12-21
EP3227963A1 (en) 2017-10-11
IL252085B (en) 2021-05-31

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