EP3692598A1 - Antenna with partially saturated dispersive ferromagnetic substrate - Google Patents

Antenna with partially saturated dispersive ferromagnetic substrate

Info

Publication number
EP3692598A1
EP3692598A1 EP18793251.2A EP18793251A EP3692598A1 EP 3692598 A1 EP3692598 A1 EP 3692598A1 EP 18793251 A EP18793251 A EP 18793251A EP 3692598 A1 EP3692598 A1 EP 3692598A1
Authority
EP
European Patent Office
Prior art keywords
antenna
dispersive
ferrite
magnet
magnetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP18793251.2A
Other languages
German (de)
French (fr)
Other versions
EP3692598B1 (en
Inventor
Evgueni KAVERINE
Sébastien PALUD
Franck Colombel
Mohamed Himdi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Universite de Rennes 1
Telediffusion de France ets Public de Diffusion
Original Assignee
Universite de Rennes 1
Telediffusion de France ets Public de Diffusion
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Universite de Rennes 1, Telediffusion de France ets Public de Diffusion filed Critical Universite de Rennes 1
Publication of EP3692598A1 publication Critical patent/EP3692598A1/en
Application granted granted Critical
Publication of EP3692598B1 publication Critical patent/EP3692598B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/44—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/005—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with variable reactance for tuning the antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/06—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with core of ferromagnetic material
    • H01Q7/08—Ferrite rod or like elongated core

Definitions

  • the invention relates to a ferromagnetic substrate antenna.
  • the invention relates to an antenna with ultracompact ferromagnetic substrate in the vertical plane compared to the wavelength, which can be used in reception or transmission in the frequency bands (30-300 kHz), hectometres (0, 3-3 MHz), HF (3-30 MHz) and metric (30-300 MHz).
  • the antenna is particularly suitable for example in broadband transmission systems or narrow band medium to high power conveying the information in the form of modulated signals or not and which propagate over the air.
  • the antenna promotes the propagation of the wave in a preferred direction (directional antenna).
  • the electrically small antennas have an impedance having a strong reactive component which does not allow their use in an effective and direct way in normal real impedance systems (typically 50 ⁇ ).
  • Impedance matching of this type of antenna is often difficult and generally allows tuning only over a narrow frequency band.
  • the narrow bandwidth of such an antenna is often unstable, which is particularly problematic on transmission, especially for high power applications.
  • DM Pozar and V. Sanchez describe the impedance matching of a microstrip antenna with a ferrite substrate for high frequency applications, ie greater than 2.8 GHz. For this, it is described the application of a field magnetic to said substrate made of YIG G-113 ferrimagnetic type and having low losses at high frequencies. It has been found that the use of this material limits the miniaturization factor of the antenna.
  • the invention aims to overcome at least some of the disadvantages of known electrically small antennas.
  • the invention aims to provide, in at least one embodiment of the invention, an ultracompact vertical polarization antenna in the vertical plane and broadband that can operate on transmission.
  • the invention also aims to provide, in at least one embodiment, an antenna providing good radiation efficiency while maintaining a wide bandwidth by stabilizing the variation of the impedance.
  • the invention also aims to provide, in at least one embodiment of the invention, a directional antenna (or directional antenna).
  • an antenna comprising:
  • the substrate is a dispersive ferromagnetic substrate, said dispersive ferrite having, as magnetic characteristics, a high relative magnetic permeability of between 10 and 10,000 and a high tangent of magnetic losses greater than 0.1, said antenna comprising means for locally modifying the magnetic characteristics of the dispersive ferrite, so that the relative magnetic permeability and magnetic losses of the dispersive ferrite are reduced gradually and locally.
  • a dispersive ferrite has high dielectric losses and / or high magnetic losses.
  • the ferromagnetic dispersive substrate used in the context of the present invention consists in particular of spinel ferrite which is well suited to the manufacture of magnetic antennas with wide bandwidth and small size.
  • An antenna according to the invention therefore makes it possible, thanks to the use of a partially saturated dispersive ferromagnetic (dispersive ferrite) substrate (that is to say whose magnetic losses and relative magnetic permeability are reduced locally and gradually), to ensure a good radiation efficiency while maintaining a wide bandwidth by stabilizing the variation of the impedance.
  • the dispersive ferrite allows this stabilization of the impedance, but strongly reduces the radiation.
  • dispersive ferrite can experience rapid heating and performance degradation in the vicinity of the Curie point during long-term, high-power emissions.
  • the gradual and local modification of the characteristics of ferrite makes it possible to compensate for this radiation reduction in order to reach a suitable gain, while maintaining the stabilization of the impedance, and with a reduced heating in emission mode.
  • the terms "vertical plane” and “horizontal plane” are understood by considering the antenna in its arrangement during its preferential operation in vertical polarization, the antenna can of course have a different orientation when it is not in operation and / or when the desired polarization is different (especially horizontal).
  • a high relative magnetic permeability is typical of ferromagnetic materials, and is much greater than 1, in particular between 10 and 10000.
  • the high tangent of magnetic losses, corresponding to high magnetic losses, is often designated by the symbol tan ⁇ whose value is greater than 0.1.
  • the magnetic loss tangent corresponds to the ratio of the imaginary part to the real part of the relative magnetic permeability. The high value of these magnetic characteristics depends on the frequency used. These values are provided at the working frequency of the antenna, i.e. at a frequency in a frequency band on which the impedance matching of the antenna is performed.
  • the antenna is adapted to receive or transmit at a frequency comprised in the frequency bands (30-300 kHz), MF (0.3-3 MHz), HF (3 -30 MHz) or metric (30-300 MHz).
  • the maximum working frequency of the antenna is of the order of 300 MHz (ie corresponding to the upper limit of the frequency band 30 - 300 MHz).
  • the high relative magnetic permeability of the dispersive ferrite makes it possible to increase the miniaturization factor of the antenna.
  • the antenna illustrated in FIG. 1 has a maximum dimension of less than 0.03 ⁇ at a working frequency equal to 30 MHz ( ⁇ denoting the corresponding wavelength) or less than 0.01 ⁇ considering only the radiating metal parts of the antenna.
  • the maximum dimension of the radiating part of the antenna of D1 would be limited to 0.22 ⁇ at this same working frequency.
  • Such limitation is due to the fact that only the high permittivity of YIG G-113 material contributes to the size reduction of the antenna.
  • the magnetic permeability and the relative permittivity of the dispersive ferrite according to the specific features of the invention both contribute to increasing the miniaturization factor of the antenna and with the feature that the contribution of the magnetic permeability is greater than that of the permittivity.
  • the gradual and local modification makes it possible locally and gradually to reduce these values, in particular up to a relative magnetic permeability lower than the permeability of the ferrite, typically between 1 and 100 and always greater than 1, and a tangent of lower magnetic losses.
  • the dispersive ferrite is thus non-homogeneous.
  • the antenna further has a directivity in the horizontal plane, without the need to be networked with other antennas nor to resort to one or external parasitic elements.
  • the non-ferrous metal forming the plates is for example copper, brass, aluminum, etc.
  • the means for locally modifying the magnetic characteristics of the dispersive ferrite are a magnet (permanent magnet or electromagnet), or at least one piece of material having a low relative magnetic permeability and a low loss tangent.
  • the magnet is disposed on a metal plate of the antenna, preferably on the radiating portion.
  • the magnet When the magnet is an electromagnet, it is powered by a DC generator, preferably variable, thus making it possible to modify the force of the magnetic field generated by the electromagnet, thus modifying the performance of the antenna (parameters S, gain and form of the radiation pattern).
  • the gain may for example vary on command, or the impedance can be adjusted to achieve that desired in the system to which the antenna is connected, for example 50 ⁇ .
  • the insert (s) of material inserted is included in the manufacture of the ferrite.
  • the arrangement of the parts can be configured to achieve desired performance.
  • the dispersive ferrite has a bulk in the horizontal plane greater than the bulk of the metal plates.
  • the bulk of the ferrites superior to the metal plates makes it possible to improve the efficiency of the radiation. If the antenna is monopole type, this feature also increases the directivity.
  • the size of the ferrites may be greater in one direction.
  • the antenna comprises at least one short circuit connecting the ground plane and the radiating part, in contact with an outline of the dispersive ferrite.
  • an antenna without short circuit is a monopole type antenna
  • an antenna having a short circuit is a semi-open type antenna
  • an antenna having a short circuit arranged opposite. the exciter at the contour of the dispersive ferrite forms a loop antenna.
  • the antenna comprises a succession of dispersive ferrite and magnet stacked alternately between the radiating portion and the ground plane.
  • the antenna thus forms a stacked antenna.
  • Stacked antennas achieve higher gains. It is furthermore possible to vary the degree of saturation of the dispersive ferrites according to the layers, thus allowing a modification of the adaptation, the gain and the radiation.
  • the radiating part comprises a metal plate between each ferrite and magnet.
  • the metal plates are interconnected.
  • the invention also relates to an antenna characterized in combination by all or some of the characteristics mentioned above or below.
  • FIG. 1 is a diagrammatic perspective exploded view of an antenna according to a first embodiment of the invention
  • FIG. 2 is a schematic perspective exploded view of an antenna according to a second embodiment of the invention.
  • FIG. 3 is a schematic side sectional view of an antenna according to the first embodiment of the invention.
  • FIG. 4 is a schematic side sectional view of an antenna according to a third embodiment of the invention.
  • FIG. 5 is a schematic side sectional view of an antenna according to the second embodiment of the invention.
  • FIG. 6 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention without magnet,
  • FIG. 7 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna seen from above according to the first embodiment of the invention with a magnet,
  • FIG. 8 is a magnetic field map showing the distribution of the static magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention with a magnet
  • FIG. 9 is a graph showing the tangent of magnetic losses in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of frequency, in the absence or in the presence of magnets having different magnetic induction values
  • FIGS. 10a and 10b are graphs respectively representing the real part and the imaginary part of the relative magnetic permeability in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of the frequency, in the absence or in the presence of magnets having different magnetic induction values,
  • FIGS. 11a, 11b and 11c are diagrammatic views from above of the dispersive ferrite of antennas according to various embodiments of the invention, comprising a magnet,
  • FIG. 12 is a schematic top view of an antenna according to one embodiment of the invention, comprising an electromagnet,
  • FIG. 13 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence or in the presence of magnets having different magnetic induction values
  • FIG. 14 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G)
  • FIG. 15 is a graph representing the reflection coefficient S u of an antenna according to the second embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
  • FIG. 16 is a radiation diagram of an antenna according to the first embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
  • FIG. 17 is a radiation diagram of an antenna according to the second embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
  • FIGS. 18a, 18b and 18c are schematic views of the top of antennas according to various embodiments of the invention, comprising an inserted part
  • FIG. 19 is a schematic perspective view of a so-called stacked antenna according to a fourth embodiment of the invention.
  • FIG. 20 is a schematic perspective view of a so-called stacked antenna according to a fifth embodiment of the invention.
  • FIG. 21 is a schematic perspective view of a so-called stacked antenna according to a sixth embodiment of the invention.
  • FIG. 22 is a schematic perspective view of a so-called stacked antenna according to a seventh embodiment of the invention.
  • FIG. 23 is a schematic perspective view of an antenna said to be stacked according to an eighth embodiment of the invention.
  • FIG. 24 is a schematic perspective view of an antenna said to be stacked according to a ninth embodiment of the invention.
  • Figure 25 is a schematic perspective view of an antenna according to a tenth embodiment of the invention.
  • FIG. 26 illustrates examples of positioning of the magnet on the radiating part of the antenna in the case of a monopole antenna
  • Figure 27 illustrates an example of positioning of the magnet on the radiating part of the antenna in the case of a semi-open antenna (loop).
  • the values of the magnetic induction of the magnets are expressed in gauss in this application, 1 gauss (of symbol G) equal to 10 -4 Tesla (of symbol T).
  • ⁇ denotes the wavelength at the main frequency (central frequency if transmitting on a frequency band) of transmission or reception of the antenna.
  • Figure 1 shows schematically in exploded perspective an antenna according to a first embodiment of the invention.
  • Figure 3 schematically shows in side section an antenna according to the first embodiment of the invention.
  • the antenna comprises two non-ferrous metal plates (for example copper, brass, aluminum, etc.), a first plate forming a radiating 4 H portion and a second plate forming a ground plane 4 B. Between the two metal plates is disposed a dispersive ferromagnetic substrate, said dispersive ferrite 1.
  • the metal plates and the dispersive ferrite 1 are in a flat shape extending mainly in a horizontal plane, so as to have a minimum vertical space requirement for a vertically polarized antenna.
  • the radiant 4 H part totally or partially covers the dispersive ferrite 1, and can be composed of several pieces having different shapes connected to each other.
  • the radiant 4H part can also take many forms complex, for example a meander as shown with reference to Figure 25 according to one embodiment of the invention.
  • the dispersive ferrite 1 has a horizontal space greater than the metal plates, especially along a length (the plates are square while the dispersive ferrite 1 is rectangular), which allows an improvement of the radiation (higher gain) .
  • the ferrite and the plates have the same size in the horizontal plane or different shapes.
  • the dispersive ferrite 1 comprises an orifice 8 allowing the passage of an exciter 6 connected to a connector 7.
  • the connector 7 is a coaxial type socket, its core is connected to the exciter 6 and its outer conductor is connected to the plane massive.
  • the radiating part and the ground plane are not directly connected by a conductive element such as a short circuit, the antenna thus formed being a monopole antenna.
  • the antenna comprises means for locally modifying the magnetic characteristics of the dispersive ferrite, here a magnet 5 disposed on one of the metal plates, preferably the radiating part as shown in this embodiment.
  • a magnet 5 disposed on one of the metal plates, preferably the radiating part as shown in this embodiment.
  • the magnet 5 has a rectangular shape. It has a length of 47 mm, a width of 22 mm and a height of 12 mm.
  • the substrate consists of a ferrite tile material referenced 4S60.
  • the tile is square in shape. It has a length of 100 mm, a width of 100 mm and a thickness of 7 mm.
  • the magnet 5 has a surface area corresponding to about 10.34% of the total area of the substrate. Such proportions ensure in particular a local and gradual modification of the magnetic characteristics of the dispersive ferrite by the magnet.
  • the distance between the radiating portion and the ground plane, corresponding to the thickness of the ferrite, is generally between ⁇ / 50,000 and ⁇ / 500 depending on the frequency used.
  • FIG. 2 schematically represents an exploded perspective view of an antenna according to a second embodiment of the invention.
  • Figure 5 represents schematically in lateral section an antenna according to the second embodiment of the invention.
  • the second embodiment is identical to the first embodiment of the invention, except for the presence of a short-circuit 2 connecting the radiating part to the ground plane, the short-circuit 2 being away from the exciter 6 so to form a semi-open type antenna (or semi-open loop) due to the absence of a short circuit at the zone 3 opposite the short circuit 2.
  • Figure 4 schematically shows in side section an antenna according to a third embodiment of the invention.
  • This embodiment is similar to the second embodiment in which the exciter 6 is placed no longer in the center of the ferrite and passing therethrough, but on a contour of the ferrite so as to extend between the ground plane 4 B and the radiating part 4 H , at the opening of the second embodiment.
  • the exciter 6, the radiating part 4 H , the short-circuit 2 and the ground plane 4 B thus form a loop, the antenna thus being a loop-type antenna.
  • Fig. 6 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention without a magnet
  • Fig. 7 is a magnetic field map. representing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention with a magnet. Radiofrequency magnetic fields are measured in ⁇ / m.
  • Fig. 8 is a magnetic field map showing the distribution of the static magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the magnet invention.
  • the static magnetic field is expressed in gauss (G).
  • the magnet 5 is a permanent magnet emitting a static field of 2000 G, or 0.2 Tesla (T).
  • the magnet 5 is advantageously disposed eccentrically with respect to the exciter 6.
  • the magnet 5 adjoins one of the sides of the ferrite substrate 1.
  • the magnet 5 is preferably arranged in one of the four zones 51, 52, 53, 54, as illustrated in FIG. 26.
  • the magnet 5 is preferably disposed at level of the area that forms the opening (reference 3 Figures 2 and 5). In this case, the magnet 5 is disposed in an eccentric zone 50, opposite the short-circuit 2 as illustrated in FIG. 27.
  • the magnet 5 covers approximately 10.34% of the surface of the substrate 1.
  • the magnet 5 can also cover the entire surface of the ferrite, to which case the radiation pattern is not changed but the antenna has a better radiation efficiency.
  • the dispersive ferrite without local modification of the characteristics makes it possible to stabilize the variation of the impedance of the antenna and thus increase the bandwidth of the antenna, but causes a fall in the radiation efficiency.
  • the local modification of the characteristics makes it possible to maintain this advantage of stabilizing the impedance variation and bandwidth increase while compensating for the fall in the radiation efficiency so as to obtain a high performance antenna.
  • FIG. 9 is a graph representing on a logarithmic scale the magnetic losses, represented by the tangent of magnetic losses in the dispersive ferrite of an antenna according to one embodiment of the invention, as a function of frequency (in MHz over a logarithmic scale), in the absence (0 G curve) or in the presence of magnets having different magnetic induction values (620 G, 1680 G and 2410G).
  • 10a and 10b are graphs respectively representing the real part and the imaginary part of the relative magnetic permeability in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of frequency (in MHz on a scale logarithmic), in the absence (0 G curve) or in the presence of magnets with different magnetic induction values (620 G, 1680 G and 2410 G).
  • the experimental results presented in the diagrams of FIGS. 9 and 10 were obtained with NiSn ferrite, commercially available under reference 4S60 and commonly used for its attenuation properties of radio waves at frequencies higher than 1 GHz.
  • the real and imaginary parts of the relative magnetic permeability are commonly designated respectively by the symbols ⁇ 'and ⁇ ".
  • the tangent of magnetic losses (often designated by the symbol tan ⁇ ) is the ratio of the imaginary part to the real part of the relative magnetic permeability.
  • the tangent of magnetic losses and the real and imaginary parts of the relative magnetic permeability are measured in the dispersive ferrite at the zones where the magnetic characteristics of the dispersive ferrite are modified.
  • the reduction of the relative magnetic permeability is particularly visible in the frequencies between 1 and 30 MHz, which forms part of the frequency band targeted by the invention. Beyond 100 MHz, the Relative magnetic permeability is low in all cases.
  • Dispersive spinel ferrites especially NiZn, known to exhibit high magnetic permeability are generally used to form coatings for absorbing electromagnetic waves, particularly the walls of anechoic chambers operating at frequencies up to 1000 MHz. In the context of the present invention, this type of ferrite is advantageously used.
  • Figures 11a, 11b and 11c show schematically from above antennas according to various embodiments of the invention, comprising a permanent magnet.
  • the shape of the magnets can be modified, resulting in a different distribution of the magnetic field generated. This different distribution causes a modification of the radiation pattern of the antenna which can therefore be adapted as needed.
  • the shapes shown as examples are rectangular (Figure 11a), circular ( Figure 11b) or triangular (Figure 11c).
  • FIG. 12 schematically shows from above an antenna according to one embodiment of the invention, comprising an electromagnet 5.
  • the electromagnet can replace a permanent magnet in the various embodiments of the antenna.
  • the electromagnet is powered by a generator 9 of variable current, thereby changing the value of the magnetic field it generates. It is thus possible to influence performances such as the parameters S of the antenna, the gain and the shape of the radiation diagram.
  • FIG. 13 is a graph representing the reflection coefficient Su of an antenna according to the first embodiment of the invention in the absence (0 G curve) or in the presence of magnets having different magnetic induction values (780).
  • G, 850 G, 1430 G for example an electromagnet, depending on the frequency (in MHz).
  • the reflection coefficient Su makes it possible to determine the impedance matching of the antenna. With the aid of the magnet adapted or by adjustment with an electromagnet, it is thus possible to choose the value of the magnetic field so as to have the desired impedance matching, for example 50 ⁇ .
  • FIG. 14 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence (SA curve for "without magnet”) or in the presence (curve AA for "with magnet”) of a permanent magnet of 2000 G, depending on the frequency (in MHz).
  • the antenna is here of monopole type.
  • FIG. 15 is a graph representing the reflection coefficient S u of an antenna according to the second embodiment of the invention in the absence (curve SA) or in the presence (curve AA) of a permanent magnet of 2000 G , depending on the frequency (in MHz).
  • the antenna is here semi-open type.
  • FIG. 16 is a radiation diagram of an antenna according to the first embodiment of the invention in the absence (SA curve) or in the presence (AA curve) of a 2000 G permanent magnet.
  • FIG. 17 is a radiation diagram of an antenna according to the second embodiment of the invention in the absence (curve SA) or in the presence (curve AA) of a permanent magnet of 2000 G.
  • the antenna without magnet is a directional antenna of low gain, while the semi-open antenna with a magnet according to the invention has a substantially similar diagram but has a greater gain in all directions.
  • the radiation pattern of the antenna as shown in FIGS. 16 and 17 can also be adjusted as a function of the relative position of the magnet 5 with respect to the substrate 1.
  • Figures 18a, 18b and 18c are schematic top views of the antenna dispersive ferrite according to various embodiments of the invention, comprising an insert.
  • the inserted pieces are pieces of material having a low relative magnetic permeability and low magnetic losses inserted into the dispersive ferrite and which result in a gradual and local reduction in the magnetic permeability and magnetic losses of the dispersive ferrite.
  • relative magnetic permeability values less than 10 are understood.
  • magnetic loss tangent values of less than 0.1 are included. As indicated above, these values are to be considered at the working frequency of the antenna, that is to say at a frequency included in a frequency band on which the impedance matching of the antenna is carried out .
  • the inserted part (s) 10 can take the place of the magnet (permanent or electromagnet) in all the embodiments of the antenna described above. Like the magnet, they can take different forms, for example those shown in FIGS. 18a, 18b and 18c.
  • the figures are similar to Figures 11a, 11b and 11c but the parts 10 are here inserted into the dispersive ferrite 1 instead of being arranged above on a metal plate (like the magnet).
  • the hatched areas shown may be composed of a single piece inserted into a block or of several inserted pieces arranged side by side. Different inserted parts may have permeabilities and / or tangent of different losses (always lower than the dispersive ferrite 1).
  • the shapes can affect the characteristics of the antenna, especially its directivity.
  • FIG. 19 diagrammatically shows in perspective a so-called stacked antenna according to a fourth embodiment of the invention.
  • a stacked antenna according to the invention comprises a plurality of dispersive ferrites and several magnets stacked between the ground plane and at least one metal plate of the radiating portion.
  • the radiating portion 4 H is formed of several metal plates connected in S or zigzag, between which are alternately a dispersive ferrite or a magnet, so that there is as much of dispersive ferrites than magnets.
  • the antenna comprises two ferrites 1 1 and 1 2 dispersive and two magnets 5 1 and 5 2 permanent.
  • the radiant 4 H part is connected to the plane 4 B by a short-circuit 2.
  • the exciter 6 passes through all the ferrites and magnets and touches only the top plate of the radiating part 4 H.
  • FIG. 20 diagrammatically shows in perspective a so-called stacked antenna according to a fifth embodiment of the invention.
  • the antenna of this embodiment is identical to the fourth mode of realization, except that the exciter is deported instead of the short circuit and feeds the antenna between the ground plane 4 B and the plate of the part 4 H which is closest to the plane 4 B ground.
  • FIG. 21 diagrammatically shows in perspective a so-called stacked antenna according to a sixth embodiment of the invention.
  • the antenna of this embodiment is identical to the fourth embodiment, except that it does not include a short-circuit 2.
  • FIG. 22 diagrammatically shows in perspective an antenna said to be stacked according to a seventh embodiment of the invention.
  • the antenna comprises a single metal plate forming the radiating part 4 H , and between the radiating part 4 H and the ground plane 4 B is a stack of dispersive ferrites and alternating magnets, here two ferrites 1 1 and 1 2 dispersive and two magnets 5 1 and 5 2 permanent.
  • FIG. 23 diagrammatically shows in perspective an antenna said stacked according to an eighth embodiment of the invention.
  • the antenna comprises a plurality of metal plates 4m, 4H 2 , 4H 3 and 4H 4 forming the radiating portion.
  • Each metal plate is connected to the exciter 6.
  • Between the plane 4 B of mass and the plate 4 H4 is a ferrite 1 2 dispersive, between the plate 4 H4 and the plate 4 H3 is a magnet 5 2 , between the plate 4 H3 and the plate 4 H2 is a dispersive ferrite 1 1 and between the plate 4 H2 and the plate A H1 is a magnet 5i.
  • FIG. 24 diagrammatically shows in perspective an antenna said to be stacked according to a ninth embodiment of the invention.
  • the antenna of this embodiment is similar to the eighth embodiment, in that it contains a plurality of metal plates 4m, 4 2 , 4 3 , 4 4 , 4 4 4 and 4 of circular shape, forming the the radiating part and connected to the exciter 6. Between the metal plates are alternately a ferrite l lt 1 2 , 1 3 or 1 4 dispersive circular or a magnet 5 1 ( 5 2 , 5 3 or 5 4 circular shape .
  • FIG. 25 diagrammatically shows in perspective an antenna said to be stacked according to a ninth embodiment of the invention.
  • the antenna of this embodiment is similar to the first mode of embodiment in that it comprises a magnet disposed on the radiating part 4H of the antenna, the antenna being separated from the ground plane 4B by the dispersive ferrite substrate 1.
  • the second plate forming the radiating portion 4H is cut to form a rectangular flat spiral.
  • this spiral is centered on the exciter 6 of the antenna.
  • dispersive ferrites, magnets, inserted parts or metal plates can take different forms. Magnets may have different values from those shown in the graphs. Stacked antennas may contain more layers.

Abstract

The invention relates to an antenna comprising at least two non-ferrous metal plates, at least one first plate forming a radiating portion (4H) and a second plate forming a ground plane (4B), at least one substrate arranged between the ground plane (4B) and the radiating portion (4H), and an exciter having a length at least equal to the thickness of the substrate, said exciter extending between the ground plane (4B) and the radiating portion (4H) and being connected to the radiating portion (4H), and adapted to supply the antenna, characterised in that the substrate is a dispersive ferromagnetic substrate referred to as a dispersive ferrite (1), the magnetic properties thereof being a high relative magnetic permeability of between 10 and 10,000 and a high magnetic loss tangent greater than 0.1, the antenna comprising means for gradually locally reducing the magnetic properties of the dispersive ferrite (1).

Description

ANTENNE À SUBSTRAT FERROMAGNÉTIQUE DISPERSIF PARTIELLEMENT SATURÉ  PARTIALLY SATURATED DISPERSIVE FERROMAGNETIC SUBSTRATE ANTENNA
1. Domaine technique de l'invention 1. Technical field of the invention
L'invention concerne une antenne à substrat ferromagnétique. En particulier, l'invention concerne une antenne à substrat ferromagnétique ultracompacte dans le plan vertical comparée à la longueur d'onde, pouvant être utilisées en réception ou en émission dans les bandes de fréquences kilométriques (30-300 kHz), hectométriques (0,3-3 MHz), décamétriques (3-30 MHz) et métriques (30-300 MHz).  The invention relates to a ferromagnetic substrate antenna. In particular, the invention relates to an antenna with ultracompact ferromagnetic substrate in the vertical plane compared to the wavelength, which can be used in reception or transmission in the frequency bands (30-300 kHz), hectometres (0, 3-3 MHz), HF (3-30 MHz) and metric (30-300 MHz).
L'antenne est particulièrement adaptée par exemple dans les systèmes d'émission large bande ou bande étroite à moyenne et forte puissance véhiculant l'information sous forme de signaux modulés ou non et qui se propagent par voie hertzienne. Selon certains modes de réalisations, l'antenne favorise la propagation de l'onde dans une direction privilégiée (antenne directive).  The antenna is particularly suitable for example in broadband transmission systems or narrow band medium to high power conveying the information in the form of modulated signals or not and which propagate over the air. According to some embodiments, the antenna promotes the propagation of the wave in a preferred direction (directional antenna).
2. Arrière-plan technologique 2. Technological background
Les antennes électriquement petites ont une impédance présentant une forte composante réactive qui ne permet par leur utilisation d'une manière efficace et directe dans des systèmes à impédance réelle normalisée (typiquement 50 Ω).  The electrically small antennas have an impedance having a strong reactive component which does not allow their use in an effective and direct way in normal real impedance systems (typically 50 Ω).
L'adaptation d'impédance de ce type d'antenne est souvent difficile et permet généralement l'accord uniquement sur une bande de fréquences étroite. La bande passante étroite d'une telle antenne est souvent instable ce qui est particulièrement problématique à l'émission, en particulier pour les applications de forte puissance.  Impedance matching of this type of antenna is often difficult and generally allows tuning only over a narrow frequency band. The narrow bandwidth of such an antenna is often unstable, which is particularly problematic on transmission, especially for high power applications.
Des solutions ont été cherchées pour stabiliser cette variation de l'impédance et ainsi augmenter la bande passante de l'antenne. Toutefois, ces solutions diminuent de manière importante l'efficacité de rayonnement de l'antenne, la rendant ainsi non utilisable dans les conditions souhaitées.  Solutions have been sought to stabilize this variation of the impedance and thus increase the bandwidth of the antenna. However, these solutions significantly reduce the radiation efficiency of the antenna, thus rendering it unusable under the desired conditions.
Dans l'article intitulé "Magnetic tuning of a microstrip antenna on a ferrite substrate" publié dans Electronic Letters, 9th June 1998, Vol. 24, No. 12, pp. 730-731 (référencé Dl ci-après), D.M. Pozar et V. Sanchez décrivent l'adaptation d'impédance d'une antenne micro-ruban à substrat en ferrite pour des applications à hautes fréquences, i.e. supérieures à 2,8 GHz. Pour cela, il est décrit l'application d'un champ magnétique audit substrat constitué en YIG G-113 de type ferrimagnétique et présentant de faibles pertes à hautes fréquences. Il a été constaté que l'utilisation de ce matériau limite le facteur de miniaturisation de l'antenne. In the article titled "Magnetic tuning of a microstrip antenna on a ferrite substrate" published in Electronic Letters, 9th June 1998, Vol. 24, No. 12, pp. 730-731 (referenced D1 below), DM Pozar and V. Sanchez describe the impedance matching of a microstrip antenna with a ferrite substrate for high frequency applications, ie greater than 2.8 GHz. For this, it is described the application of a field magnetic to said substrate made of YIG G-113 ferrimagnetic type and having low losses at high frequencies. It has been found that the use of this material limits the miniaturization factor of the antenna.
Dans l'article intitulé "Magneto-dielectric properties of doped ferrite based nanosized ceramics over very high frequency range", publié dans Engineering Science and Technology, an International Journal 19 (2016) pp. 911-916, Ashish Saini et al. décrivent un matériau magnéto-diélectrique dont ils cherchent à réduire les pertes diélectriques et magnétiques pour miniaturiser des antennes radar opérant à environ 100 MHz. 3. Objectifs de l'invention  In the article entitled "Magneto-dielectric properties of doped ferrite based nanosized ceramics over very high frequency range", published in Engineering Science and Technology, International Journal 19 (2016) pp. 911-916, Ashish Saini et al. describe a magneto-dielectric material which they seek to reduce the dielectric and magnetic losses to miniaturize radar antennas operating at about 100 MHz. 3. Objectives of the invention
L'invention vise à pallier au moins certains des inconvénients des antennes électriquement petites connues.  The invention aims to overcome at least some of the disadvantages of known electrically small antennas.
En particulier, l'invention vise à fournir, dans au moins un mode de réalisation de l'invention, une antenne à polarisation verticale ultracompacte dans le plan vertical et large bande qui peut fonctionner à l'émission.  In particular, the invention aims to provide, in at least one embodiment of the invention, an ultracompact vertical polarization antenna in the vertical plane and broadband that can operate on transmission.
L'invention vise aussi à fournir, dans au moins un mode de réalisation, une antenne assurant une bonne efficacité de rayonnement tout en conservant une large bande passante par stabilisation de la variation de l'impédance.  The invention also aims to provide, in at least one embodiment, an antenna providing good radiation efficiency while maintaining a wide bandwidth by stabilizing the variation of the impedance.
L'invention vise aussi à fournir, dans au moins un mode de réalisation de l'invention, une antenne directionnelle (ou antenne directive).  The invention also aims to provide, in at least one embodiment of the invention, a directional antenna (or directional antenna).
4. Exposé de l'invention 4. Presentation of the invention
Pour ce faire, l'invention concerne une antenne, comprenant :  To do this, the invention relates to an antenna, comprising:
au moins deux plaques en métal non ferreux s'étendant principalement selon un plan horizontal, au moins une première plaque formant une partie rayonnante et une deuxième plaque formant un plan de masse, au moins un substrat s'étendant principalement selon un plan horizontal, disposé entre le plan de masse et la partie rayonnante, un excitateur de longueur au moins égale à l'épaisseur du substrat, s'étendant entre le plan de masse et la partie rayonnante et relié à la partie rayonnante, et adapté pour alimenter l'antenne, caractérisée en ce que le substrat est un substrat ferromagnétique dispersif, dit ferrite dispersif, présentant comme caractéristiques magnétiques une haute perméabilité magnétique relative comprise entre 10 et 10000 et une haute tangente de pertes magnétiques supérieure à 0,1, ladite antenne comprenant des moyens de modification locale des caractéristiques magnétiques du ferrite dispersif, de sorte à ce que la perméabilité magnétique relative et les pertes magnétiques du ferrite dispersif soient réduites graduellement et localement. at least two non-ferrous metal plates extending mainly in a horizontal plane, at least one first plate forming a radiating part and a second plate forming a ground plane, at least one substrate extending mainly in a horizontal plane, arranged between the ground plane and the radiating part, an exciter of length at least equal to the thickness of the substrate, extending between the ground plane and the radiating part and connected to the radiating part, and adapted to feed the antenna , characterized in that the substrate is a dispersive ferromagnetic substrate, said dispersive ferrite having, as magnetic characteristics, a high relative magnetic permeability of between 10 and 10,000 and a high tangent of magnetic losses greater than 0.1, said antenna comprising means for locally modifying the magnetic characteristics of the dispersive ferrite, so that the relative magnetic permeability and magnetic losses of the dispersive ferrite are reduced gradually and locally.
Par définition, un ferrite dispersif présente de fortes pertes diélectriques et/ou de fortes pertes magnétiques. Le substrat ferromagnétique dispersif utilisé dans le cadre de la présente invention est constitué en particulier de ferrite spinelle qui est bien adapté à la fabrication d'antennes magnétiques à large bande passante et de faible dimension. Une antenne selon l'invention permet donc, grâce à l'utilisation d'un substrat ferromagnétique dispersif (ferrite dispersif) partiellement saturé (c'est-à-dire dont les pertes magnétiques et la perméabilité magnétique relative sont réduites localement et graduellement), d'assurer une bonne efficacité de rayonnement tout en conservant une large bande passante par stabilisation de la variation de l'impédance. En effet, le ferrite dispersif permet cette stabilisation de l'impédance, mais réduit fortement le rayonnement. De plus, le ferrite dispersif peut connaître un échauffement rapide et une dégradation de performances au voisinage du point de Curie lors d'émissions longue durée et forte puissance. La modification graduelle et locale des caractéristiques de du ferrite permet de compenser cette réduction de rayonnement afin d'atteindre un gain convenable, tout en conservant la stabilisation de l'impédance, et avec un échauffement réduit en mode émission.  By definition, a dispersive ferrite has high dielectric losses and / or high magnetic losses. The ferromagnetic dispersive substrate used in the context of the present invention consists in particular of spinel ferrite which is well suited to the manufacture of magnetic antennas with wide bandwidth and small size. An antenna according to the invention therefore makes it possible, thanks to the use of a partially saturated dispersive ferromagnetic (dispersive ferrite) substrate (that is to say whose magnetic losses and relative magnetic permeability are reduced locally and gradually), to ensure a good radiation efficiency while maintaining a wide bandwidth by stabilizing the variation of the impedance. Indeed, the dispersive ferrite allows this stabilization of the impedance, but strongly reduces the radiation. In addition, dispersive ferrite can experience rapid heating and performance degradation in the vicinity of the Curie point during long-term, high-power emissions. The gradual and local modification of the characteristics of ferrite makes it possible to compensate for this radiation reduction in order to reach a suitable gain, while maintaining the stabilization of the impedance, and with a reduced heating in emission mode.
L'antenne ainsi réalisée est une antenne à polarisation verticale ultracompacte dans le plan vertical (hauteur de λ/1400 par exemple à λ=30 MHz) et large bande qui peut fonctionner à l'émission. Les termes « plan vertical » et « plan horizontal » s'entendent en considérant l'antenne dans sa disposition pendant son fonctionnement préférentiel en polarisation verticale, l'antenne pouvant bien entendu avoir une orientation différente lorsqu'elle n'est pas en fonctionnement et/ou lorsque la polarisation souhaitée est différente (notamment horizontale).  The antenna thus produced is an ultra-compact vertical polarization antenna in the vertical plane (height of λ / 1400, for example at λ = 30 MHz) and broadband which can operate on transmission. The terms "vertical plane" and "horizontal plane" are understood by considering the antenna in its arrangement during its preferential operation in vertical polarization, the antenna can of course have a different orientation when it is not in operation and / or when the desired polarization is different (especially horizontal).
Une haute perméabilité magnétique relative est typique des matériaux ferromagnétiques, et est largement supérieure à 1, en particulier comprise entre 10 et 10000. La haute tangente de pertes magnétiques, correspondant à de hautes pertes magnétiques, est souvent désignée par le symbole tan δ dont la valeur est supérieure à 0,1. La tangente de pertes magnétique correspond au rapport de la partie imaginaire sur la partie réelle de la perméabilité magnétique relative. La valeur haute de ces caractéristiques magnétiques dépend de la fréquence utilisée. Ces valeurs sont fournies à la fréquence de travail de l'antenne, c'est-à-dire à une fréquence comprise dans une bande de fréquences sur laquelle l'adaptation d'impédance de l'antenne est effectuée. Dans le cadre de la présente invention, on rappelle que l'antenne est adaptée à recevoir ou émettre à une fréquence comprise dans les bandes de fréquences kilométriques (30- 300 kHz), hectométriques (0,3-3 MHz), décamétriques (3-30 MHz) ou métriques (30-300 MHz). Ainsi, la fréquence maximale de travail de l'antenne est de l'ordre de 300 MHz (i.e. correspondant à la borne supérieure de la bande de fréquences métriques 30 - 300 MHz). A high relative magnetic permeability is typical of ferromagnetic materials, and is much greater than 1, in particular between 10 and 10000. The high tangent of magnetic losses, corresponding to high magnetic losses, is often designated by the symbol tan δ whose value is greater than 0.1. The magnetic loss tangent corresponds to the ratio of the imaginary part to the real part of the relative magnetic permeability. The high value of these magnetic characteristics depends on the frequency used. These values are provided at the working frequency of the antenna, i.e. at a frequency in a frequency band on which the impedance matching of the antenna is performed. In the context of the present invention, it will be recalled that the antenna is adapted to receive or transmit at a frequency comprised in the frequency bands (30-300 kHz), MF (0.3-3 MHz), HF (3 -30 MHz) or metric (30-300 MHz). Thus, the maximum working frequency of the antenna is of the order of 300 MHz (ie corresponding to the upper limit of the frequency band 30 - 300 MHz).
A ces fréquences, notamment à des fréquences situées en bas de bandes (i.e. 30 kHz, 0,3 MHz ou 30 MHz), la haute perméabilité magnétique relative du ferrite dispersif permet d'augmenter le facteur de miniaturisation de l'antenne. Par exemple, l'antenne illustrée à la figure 1 a une dimension maximale inférieure à 0,03 λ à une fréquence de travail égale à 30 MHz (λ désignant la longueur d'onde correspondante) ou inférieure à 0,01 λ en considérant uniquement les parties métalliques rayonnantes de l'antenne.  At these frequencies, particularly at lower band frequencies (i.e. 30 kHz, 0.3 MHz or 30 MHz), the high relative magnetic permeability of the dispersive ferrite makes it possible to increase the miniaturization factor of the antenna. For example, the antenna illustrated in FIG. 1 has a maximum dimension of less than 0.03 λ at a working frequency equal to 30 MHz (λ denoting the corresponding wavelength) or less than 0.01 λ considering only the radiating metal parts of the antenna.
Par comparaison, la dimensions maximale de la partie rayonnante de l'antenne de Dl serait limitée à 0,22 λ à cette même fréquence de travail. Une telle limitation provient du fait que seule la permittivité élevée du matériau YIG G-113 participe à la réduction de taille de l'antenne. Au contraire, la perméabilité magnétique et la permittivité relative du ferrite dispersif selon les spécificités de l'invention contribuent toutes deux à augmenter le facteur de miniaturisation de l'antenne et avec la particularité que la contribution de la perméabilité magnétique est plus forte que celle de la permittivité. La modification graduelle et locale permet de réduire localement et graduellement ces valeurs, notamment jusqu'à une perméabilité magnétique relative inférieure à la perméabilité du ferrite, typiquement comprise entre 1 et 100 et toujours supérieure à 1, et une tangente de pertes magnétiques plus faibles. Le ferrite dispersive est ainsi non homogène. L'antenne présente en outre une directivité dans le plan horizontal, sans nécessiter d'être mise en réseau avec d'autres antennes ni avoir recours à un ou des éléments parasites extérieurs. By comparison, the maximum dimension of the radiating part of the antenna of D1 would be limited to 0.22 λ at this same working frequency. Such limitation is due to the fact that only the high permittivity of YIG G-113 material contributes to the size reduction of the antenna. On the contrary, the magnetic permeability and the relative permittivity of the dispersive ferrite according to the specific features of the invention both contribute to increasing the miniaturization factor of the antenna and with the feature that the contribution of the magnetic permeability is greater than that of the permittivity. The gradual and local modification makes it possible locally and gradually to reduce these values, in particular up to a relative magnetic permeability lower than the permeability of the ferrite, typically between 1 and 100 and always greater than 1, and a tangent of lower magnetic losses. The dispersive ferrite is thus non-homogeneous. The antenna further has a directivity in the horizontal plane, without the need to be networked with other antennas nor to resort to one or external parasitic elements.
Le métal non ferreux formant les plaques est par exemple du cuivre, du laiton, de l'aluminium, etc.  The non-ferrous metal forming the plates is for example copper, brass, aluminum, etc.
Selon les modes de réalisation, les moyens de modification locale des caractéristiques magnétiques du ferrite dispersif sont un aimant (aimant permanent ou électroaimant), ou au moins une pièce de matériau ayant une faible perméabilité magnétique relative et une faible tangente de pertes. According to the embodiments, the means for locally modifying the magnetic characteristics of the dispersive ferrite are a magnet (permanent magnet or electromagnet), or at least one piece of material having a low relative magnetic permeability and a low loss tangent.
L'aimant est disposé sur une plaque métallique de l'antenne, de préférence sur la partie rayonnante.  The magnet is disposed on a metal plate of the antenna, preferably on the radiating portion.
Lorsque l'aimant est un électroaimant, il est alimenté par un générateur de courant continu, de préférence variable, permettant ainsi de modifier la force du champ magnétique généré par l'électroaimant, modifiant ainsi les performances de l'antenne (paramètres S, gain et forme du diagramme de rayonnement). Le gain peut par exemple varier sur commande, ou l'impédance peut être réglée pour atteindre celle souhaitée dans le système auquel l'antenne est connectée, par exemple 50 Ω.  When the magnet is an electromagnet, it is powered by a DC generator, preferably variable, thus making it possible to modify the force of the magnetic field generated by the electromagnet, thus modifying the performance of the antenna (parameters S, gain and form of the radiation pattern). The gain may for example vary on command, or the impedance can be adjusted to achieve that desired in the system to which the antenna is connected, for example 50 Ω.
La ou les pièces de matériau insérées sont incluses à la fabrication du ferrite. L'agencement des pièces peut être configuré pour atteindre des performances désirées.  The insert (s) of material inserted is included in the manufacture of the ferrite. The arrangement of the parts can be configured to achieve desired performance.
Avantageusement et selon l'invention, le ferrite dispersive présente un encombrement dans le plan horizontal supérieur à l'encombrement des plaques en métal. Advantageously and according to the invention, the dispersive ferrite has a bulk in the horizontal plane greater than the bulk of the metal plates.
Selon cet aspect de l'invention, l'encombrement des ferrites supérieur aux plaques de métal permet l'amélioration de l'efficacité du rayonnement. Si l'antenne est de type monopôle, cette caractéristique permet aussi d'augmenter la directivité. L'encombrement des ferrites peut être supérieur dans une seule direction. Avantageusement et selon l'invention, l'antenne comprend au moins un court- circuit reliant le plan de masse et la partie rayonnante, en contact avec un contour du ferrite dispersif. According to this aspect of the invention, the bulk of the ferrites superior to the metal plates makes it possible to improve the efficiency of the radiation. If the antenna is monopole type, this feature also increases the directivity. The size of the ferrites may be greater in one direction. Advantageously and according to the invention, the antenna comprises at least one short circuit connecting the ground plane and the radiating part, in contact with an outline of the dispersive ferrite.
Selon cet aspect de l'invention, une antenne sans court-circuit est une antenne de type monopôle, une antenne présentant un court-circuit est une antenne de type semi-ouvert, et une antenne présentant un court-circuit disposé à l'opposé de l'excitateur au niveau du contour du ferrite dispersif forme une antenne de type boucle.  According to this aspect of the invention, an antenna without short circuit is a monopole type antenna, an antenna having a short circuit is a semi-open type antenna, and an antenna having a short circuit arranged opposite. the exciter at the contour of the dispersive ferrite forms a loop antenna.
Avantageusement et selon l'invention, l'antenne comprend une succession de ferrite dispersif et d'aimant empilés alternativement entre la partie rayonnante et le plan de masse. Advantageously and according to the invention, the antenna comprises a succession of dispersive ferrite and magnet stacked alternately between the radiating portion and the ground plane.
Selon cet aspect de l'invention, l'antenne forme ainsi une antenne empilée. According to this aspect of the invention, the antenna thus forms a stacked antenna.
Les antennes empilées permettent d'atteindre des gains plus élevés. Il est en outre possible de faire varier le degré de saturation des ferrites dispersifs selon les couches, permettant ainsi une modification de l'adaptation, du gain et du rayonnement. Stacked antennas achieve higher gains. It is furthermore possible to vary the degree of saturation of the dispersive ferrites according to the layers, thus allowing a modification of the adaptation, the gain and the radiation.
Avantageusement et selon ce dernier aspect de l'invention, la partie rayonnante comprend une plaque en métal entre chaque ferrite et aimant.  Advantageously and according to this last aspect of the invention, the radiating part comprises a metal plate between each ferrite and magnet.
Avantageusement et selon ce dernier aspect de l'invention, les plaques de métal sont reliées entre elles.  Advantageously and according to this last aspect of the invention, the metal plates are interconnected.
L'invention concerne également une antenne caractérisée en combinaison par tout ou partie des caractéristiques mentionnées ci-dessus ou ci-après. The invention also relates to an antenna characterized in combination by all or some of the characteristics mentioned above or below.
5. Liste des figures 5. List of figures
D'autres buts, caractéristiques et avantages de l'invention apparaîtront à la lecture de la description suivante donnée à titre uniquement non limitatif et qui se réfère aux figures annexées dans lesquelles :  Other objects, features and advantages of the invention will become apparent on reading the following description given solely by way of non-limiting example and which refers to the appended figures in which:
- la figure 1 est une vue schématique en perspective éclatée d'une antenne selon un premier mode de réalisation de l'invention, FIG. 1 is a diagrammatic perspective exploded view of an antenna according to a first embodiment of the invention,
la figure 2 est une vue schématique en perspective éclatée d'une antenne selon un deuxième mode de réalisation de l'invention,  FIG. 2 is a schematic perspective exploded view of an antenna according to a second embodiment of the invention,
la figure 3 est une vue schématique en coupe latérale d'une antenne selon le premier mode de réalisation de l'invention,  FIG. 3 is a schematic side sectional view of an antenna according to the first embodiment of the invention,
la figure 4 est une vue schématique en coupe latérale d'une antenne selon un troisième mode de réalisation de l'invention, FIG. 4 is a schematic side sectional view of an antenna according to a third embodiment of the invention,
la figure 5 est une vue schématique en coupe latérale d'une antenne selon le deuxième mode de réalisation de l'invention, FIG. 5 is a schematic side sectional view of an antenna according to the second embodiment of the invention,
la figure 6 est une cartographie de champ magnétique représentant la distribution du champ magnétique radiofréquence dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention sans aimant, FIG. 6 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention without magnet,
la figure 7 est une cartographie de champ magnétique représentant la distribution du champ magnétique radiofréquence dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention avec aimant, FIG. 7 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna seen from above according to the first embodiment of the invention with a magnet,
la figure 8 est une cartographie de champ magnétique représentant la distribution du champ magnétique statique dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention avec aimant, la figure 9 est un graphique représentant la tangente de pertes magnétiques dans le ferrite dispersif d'une antenne selon un mode de réalisation de l'invention en fonction de la fréquence, en l'absence ou en présence d'aimants ayant différentes valeurs d'induction magnétique, FIG. 8 is a magnetic field map showing the distribution of the static magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention with a magnet, FIG. 9 is a graph showing the tangent of magnetic losses in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of frequency, in the absence or in the presence of magnets having different magnetic induction values,
les figures 10a et 10b sont des graphiques représentant respectivement la partie réelle et la partie imaginaire de la perméabilité magnétique relative dans le ferrite dispersif d'une antenne selon un mode de réalisation de l'invention en fonction de la fréquence, en l'absence ou en présence d'aimants ayant différentes valeurs d'induction magnétique, FIGS. 10a and 10b are graphs respectively representing the real part and the imaginary part of the relative magnetic permeability in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of the frequency, in the absence or in the presence of magnets having different magnetic induction values,
les figures lia, 11b et 11c sont des vues schématiques du dessus de le ferrite dispersif d'antennes selon différents modes de réalisation de l'invention, comprenant un aimant, FIGS. 11a, 11b and 11c are diagrammatic views from above of the dispersive ferrite of antennas according to various embodiments of the invention, comprising a magnet,
la figure 12 est une vue schématique du dessus d'une antenne selon un mode de réalisation de l'invention, comprenant un électro-aimant, FIG. 12 is a schematic top view of an antenna according to one embodiment of the invention, comprising an electromagnet,
la figure 13 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le premier mode de réalisation de l'invention en l'absence ou en présence d'aimants ayant différentes valeurs d'induction magnétique, la figure 14 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le premier mode de réalisation de l'invention en l'absence ou en présence d'un aimant permanent de 2000 gauss (G), FIG. 13 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence or in the presence of magnets having different magnetic induction values, FIG. 14 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
la figure 15 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le deuxième mode de réalisation de l'invention en l'absence ou en présence d'un aimant permanent de 2000 gauss (G), FIG. 15 is a graph representing the reflection coefficient S u of an antenna according to the second embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
la figure 16 est un diagramme de rayonnement d'une antenne selon le premier mode de réalisation de l'invention en l'absence ou en présence d'un aimant permanent de 2000 gauss (G), FIG. 16 is a radiation diagram of an antenna according to the first embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
la figure 17 est un diagramme de rayonnement d'une antenne selon le deuxième mode de réalisation de l'invention en l'absence ou en présence d'un aimant permanent de 2000 gauss (G), FIG. 17 is a radiation diagram of an antenna according to the second embodiment of the invention in the absence or in the presence of a 2000 gauss permanent magnet (G),
les figures 18a, 18b et 18c sont des vues schématiques du dessus d'antennes selon différents modes de réalisation de l'invention, comprenant une pièce insérée, FIGS. 18a, 18b and 18c are schematic views of the top of antennas according to various embodiments of the invention, comprising an inserted part,
la figure 19 est une vue schématique en perspective d'une antenne dite empilée selon un quatrième mode de réalisation de l'invention, FIG. 19 is a schematic perspective view of a so-called stacked antenna according to a fourth embodiment of the invention,
la figure 20 est une vue schématique en perspective d'une antenne dite empilée selon un cinquième mode de réalisation de l'invention, FIG. 20 is a schematic perspective view of a so-called stacked antenna according to a fifth embodiment of the invention,
la figure 21 est une vue schématique en perspective d'une antenne dite empilée selon un sixième mode de réalisation de l'invention, FIG. 21 is a schematic perspective view of a so-called stacked antenna according to a sixth embodiment of the invention,
la figure 22 est une vue schématique en perspective d'une antenne dite empilée selon un septième mode de réalisation de l'invention, FIG. 22 is a schematic perspective view of a so-called stacked antenna according to a seventh embodiment of the invention,
la figure 23 est une vue schématique en perspective d'une antenne dite empilée selon un huitième mode de réalisation de l'invention, FIG. 23 is a schematic perspective view of an antenna said to be stacked according to an eighth embodiment of the invention,
la figure 24 est une vue schématique en perspective d'une antenne dite empilée selon un neuvième mode de réalisation de l'invention, FIG. 24 is a schematic perspective view of an antenna said to be stacked according to a ninth embodiment of the invention,
la figure 25 est une vue schématique en perspective d'une antenne selon un dixième mode de réalisation de l'invention ; Figure 25 is a schematic perspective view of an antenna according to a tenth embodiment of the invention;
la figure 26 illustre des exemples de positionnement de l'aimant sur la partie rayonnante de l'antenne dans le cas d'une antenne monopôle ; la figure 27 illustre un exemple de positionnement de l'aimant sur la partie rayonnante de l'antenne dans le cas d'une antenne semi-ouverte (boucle). FIG. 26 illustrates examples of positioning of the magnet on the radiating part of the antenna in the case of a monopole antenna; Figure 27 illustrates an example of positioning of the magnet on the radiating part of the antenna in the case of a semi-open antenna (loop).
6. Description détaillée d'un mode de réalisation de l'invention 6. Detailed description of an embodiment of the invention
Les réalisations suivantes sont des exemples. Bien que la description se réfère à un ou plusieurs modes de réalisation, ceci ne signifie pas nécessairement que chaque référence concerne le même mode de réalisation, ou que les caractéristiques s'appliquent seulement à un seul mode de réalisation. De simples caractéristiques de différents modes de réalisation peuvent également être combinées pour fournir d'autres réalisations. Sur les figures, les échelles et les proportions ne sont pas strictement respectées et ce, à des fins d'illustration et de clarté.  The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments. Figures, scales and proportions are not strictly adhered to for the purpose of illustration and clarity.
Les valeurs de l'induction magnétique des aimants est exprimé en gauss dans cette demande, 1 gauss (de symbole G) valant 10"4 tesla (de symbole T). The values of the magnetic induction of the magnets are expressed in gauss in this application, 1 gauss (of symbol G) equal to 10 -4 Tesla (of symbol T).
Les antennes représentées sont disposées selon leur mode de fonctionnement préférentiel avec une polarisation verticale, λ désigne la longueur d'onde à la fréquence principale (fréquence centrale si émission sur une bande de fréquence) d'émission ou de réception de l'antenne.  The antennas shown are arranged according to their preferred mode of operation with a vertical polarization, λ denotes the wavelength at the main frequency (central frequency if transmitting on a frequency band) of transmission or reception of the antenna.
La figure 1 représente schématiquement en perspective éclatée une antenne selon un premier mode de réalisation de l'invention. La figure 3 représente schématiquement en coupe latérale une antenne selon le premier mode de réalisation de l'invention. Figure 1 shows schematically in exploded perspective an antenna according to a first embodiment of the invention. Figure 3 schematically shows in side section an antenna according to the first embodiment of the invention.
L'antenne comprend deux plaques en métal non ferreux (par exemple cuivre, laiton, aluminium, etc.), une première plaque formant une partie 4H rayonnante et une deuxième plaque formant un plan 4B de masse. Entre les deux plaques en métal est disposé un substrat ferromagnétique dispersif, dit ferrite 1 dispersif. Les plaques en métal et le ferrite 1 dispersif se présentent sous une forme plate s'étendant principalement selon un plan horizontal, de sorte à présenter un encombrement vertical minimal pour une antenne à polarisation verticale. The antenna comprises two non-ferrous metal plates (for example copper, brass, aluminum, etc.), a first plate forming a radiating 4 H portion and a second plate forming a ground plane 4 B. Between the two metal plates is disposed a dispersive ferromagnetic substrate, said dispersive ferrite 1. The metal plates and the dispersive ferrite 1 are in a flat shape extending mainly in a horizontal plane, so as to have a minimum vertical space requirement for a vertically polarized antenna.
La partie 4H rayonnante recouvre totalement ou partiellement le ferrite 1 dispersif, et peut être composée de plusieurs pièces ayant des formes différentes reliées entre elles. La partie 4H rayonnante peut aussi se présenter sous plusieurs formes complexes, par exemple un méandre comme représenté en référence avec la figure 25 selon un mode de réalisation de l'invention. The radiant 4 H part totally or partially covers the dispersive ferrite 1, and can be composed of several pieces having different shapes connected to each other. The radiant 4H part can also take many forms complex, for example a meander as shown with reference to Figure 25 according to one embodiment of the invention.
Dans ce mode de réalisation, le ferrite 1 dispersif présente un encombrement horizontal supérieur aux plaques en métal, notamment selon une longueur (les plaques sont carrées tandis que le ferrite 1 dispersif est rectangulaire), ce qui permet une amélioration du rayonnement (gain supérieur). Selon d'autres modes de réalisation, le ferrite et les plaques ont le même encombrement dans le plan horizontal ou des formes différentes.  In this embodiment, the dispersive ferrite 1 has a horizontal space greater than the metal plates, especially along a length (the plates are square while the dispersive ferrite 1 is rectangular), which allows an improvement of the radiation (higher gain) . According to other embodiments, the ferrite and the plates have the same size in the horizontal plane or different shapes.
Le ferrite 1 dispersif comprend un orifice 8 permettant la traversée d'un excitateur 6 relié à un connecteur 7. Lorsque le connecteur 7 est une prise de type coaxiale, son âme est reliée à l'excitateur 6 et son conducteur extérieur est relié au plan de masse. La partie rayonnante et le plan de masse ne sont pas directement reliés par un élément conducteur tel qu'un court-circuit, l'antenne ainsi formée étant une antenne monopôle.  The dispersive ferrite 1 comprises an orifice 8 allowing the passage of an exciter 6 connected to a connector 7. When the connector 7 is a coaxial type socket, its core is connected to the exciter 6 and its outer conductor is connected to the plane massive. The radiating part and the ground plane are not directly connected by a conductive element such as a short circuit, the antenna thus formed being a monopole antenna.
L'antenne comprend des moyens de modification locale des caractéristiques magnétiques du ferrite dispersif, ici un aimant 5 disposé sur une des plaques en métal, de préférence la partie rayonnante comme représenté dans ce mode de réalisation. En disposant l'aimant 5 sur la partie rayonnante de l'antenne, il est possible d'atteindre un rendement d'antenne plus élevé avec un gain plus élevé dans une direction donnée.  The antenna comprises means for locally modifying the magnetic characteristics of the dispersive ferrite, here a magnet 5 disposed on one of the metal plates, preferably the radiating part as shown in this embodiment. By placing the magnet 5 on the radiating part of the antenna, it is possible to achieve a higher antenna efficiency with a higher gain in a given direction.
Par exemple, l'aimant 5 a une forme rectangulaire. Il a une longueur de 47 mm, une largeur de 22 mm et une hauteur de 12 mm. Le substrat est constitué par une tuile de ferrite en matériau référencé 4S60. La tuile est de forme carrée. Elle a une longueur de 100 mm, une largeur de 100 mm et une épaisseur de 7 mm. Ainsi, l'aimant 5 a une surface correspondant à environ 10,34 % de la surface totale du substrat. De telles proportions assurent notamment une modification locale et graduelle des caractéristiques magnétiques du ferrite dispersif par l'aimant.  For example, the magnet 5 has a rectangular shape. It has a length of 47 mm, a width of 22 mm and a height of 12 mm. The substrate consists of a ferrite tile material referenced 4S60. The tile is square in shape. It has a length of 100 mm, a width of 100 mm and a thickness of 7 mm. Thus, the magnet 5 has a surface area corresponding to about 10.34% of the total area of the substrate. Such proportions ensure in particular a local and gradual modification of the magnetic characteristics of the dispersive ferrite by the magnet.
La distance entre la partie rayonnante et le plan de masse, correspondant à l'épaisseur du ferrite, est généralement comprise entre λ/50 000 et λ/500 selon la fréquence utilisée.  The distance between the radiating portion and the ground plane, corresponding to the thickness of the ferrite, is generally between λ / 50,000 and λ / 500 depending on the frequency used.
La figure 2 représente schématiquement en perspective éclatée une antenne selon un deuxième mode de réalisation de l'invention. La figure 5 représente schématiquement en coupe latérale une antenne selon le deuxième mode de réalisation de l'invention. FIG. 2 schematically represents an exploded perspective view of an antenna according to a second embodiment of the invention. Figure 5 represents schematically in lateral section an antenna according to the second embodiment of the invention.
Le deuxième mode de réalisation est identique au premier mode de réalisation de l'invention, excepté la présence d'un court-circuit 2 reliant la partie rayonnante au plan de masse, le court-circuit 2 étant éloigné de l'excitateur 6 de sorte à former une antenne de type semi-ouverte (ou boucle semi-ouverte) grâce à l'absence de court- circuit au niveau de la zone 3 opposée au court-circuit 2.  The second embodiment is identical to the first embodiment of the invention, except for the presence of a short-circuit 2 connecting the radiating part to the ground plane, the short-circuit 2 being away from the exciter 6 so to form a semi-open type antenna (or semi-open loop) due to the absence of a short circuit at the zone 3 opposite the short circuit 2.
La figure 4 représente schématiquement en coupe latérale une antenne selon un troisième mode de réalisation de l'invention.  Figure 4 schematically shows in side section an antenna according to a third embodiment of the invention.
Ce mode de réalisation est similaire au deuxième mode de réalisation dans lequel l'excitateur 6 est disposé non plus au centre du ferrite et traversant celle-ci, mais sur un contour du ferrite de sorte à s'étendre entre le plan 4B de masse et la partie rayonnante 4H, au niveau de l'ouverture du deuxième mode de réalisation. L'excitateur 6, la partie rayonnante 4H, le court-circuit 2 et le plan 4B de masse forment ainsi une boucle, l'antenne étant ainsi une antenne de type boucle. This embodiment is similar to the second embodiment in which the exciter 6 is placed no longer in the center of the ferrite and passing therethrough, but on a contour of the ferrite so as to extend between the ground plane 4 B and the radiating part 4 H , at the opening of the second embodiment. The exciter 6, the radiating part 4 H , the short-circuit 2 and the ground plane 4 B thus form a loop, the antenna thus being a loop-type antenna.
La figure 6 est une cartographie de champ magnétique représentant la distribution du champ magnétique radiofréquence dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention sans aimant, et la figure 7 est une cartographie de champ magnétique représentant la distribution du champ magnétique radiofréquence dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention avec aimant. Les champs magnétiques radiofréquence sont mesurés en άΒμΑ/m. La figure 8 est une cartographie de champ magnétique représentant la distribution du champ magnétique statique dans le ferrite dispersif d'une antenne vue de dessus selon le premier mode de réalisation de l'invention avec aimant. Le champ magnétique statique est exprimé en gauss (G). Par exemple, l'aimant 5 est un aimant permanent émettant un champ statique de 2000 G, soit 0.2 Tesla (T). Fig. 6 is a magnetic field map showing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention without a magnet, and Fig. 7 is a magnetic field map. representing the distribution of the radiofrequency magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the invention with a magnet. Radiofrequency magnetic fields are measured in άΒμΑ / m. Fig. 8 is a magnetic field map showing the distribution of the static magnetic field in the dispersive ferrite of an antenna viewed from above according to the first embodiment of the magnet invention. The static magnetic field is expressed in gauss (G). For example, the magnet 5 is a permanent magnet emitting a static field of 2000 G, or 0.2 Tesla (T).
On remarque sur la figure 7 l'introduction d'une dissymétrie en amplitude due à l'inhomogénéité du champ statique de commande généré par l'aimant (représenté sur la figure 8). Ce champ statique généré par l'aimant provoque une modification locale des caractéristiques du ferrite dispersif. En particulier, cette modification est une réduction locale et graduelle de la perméabilité magnétique relative et des pertes magnétiques du ferrite dispersif. D'un point de vue du fonctionnement de l'antenne, cela se traduit par une dissymétrie dans le diagramme de rayonnement ce qui conduit à une augmentation de la directivité de l'antenne, comme visible par exemple sur la figure 16. En complément, comme la perméabilité magnétique relative et les pertes du ferrite sont réduites (voir figure 9), le gain est augmenté d'une manière très favorable. Note in Figure 7 the introduction of an asymmetry in amplitude due to the inhomogeneity of the static control field generated by the magnet (shown in Figure 8). This static field generated by the magnet causes a local modification characteristics of the dispersive ferrite. In particular, this modification is a local and gradual reduction of the relative magnetic permeability and the magnetic losses of the dispersive ferrite. From the point of view of the operation of the antenna, this results in an asymmetry in the radiation pattern which leads to an increase in the directivity of the antenna, as can be seen for example in FIG. 16. In addition, since the relative magnetic permeability and the losses of the ferrite are reduced (see FIG. 9), the gain is increased in a very favorable manner.
Pour former cette dissymétrie, l'aimant 5 est avantageusement disposé excentré par rapport à l'excitateur 6. De préférence, l'aimant 5 jouxte un des côtés du substrat de ferrite l.Par exemple, lorsque l'antenne est de type monopôle, l'aimant 5 est de préférence disposé dans l'une des quatre zones 51, 52, 53, 54, comme illustré sur la figure 26. Lorsque l'antenne est de type semi-ouverte, l'aimant 5 est de préférence disposé au niveau de la zone qui forme l'ouverture (référence 3 figures 2 et 5). Dans ce cas, l'aimant 5 est disposé dans une zone excentrée 50, à l'opposé du court-circuit 2 comme illustré sur la figure 27.  To form this dissymmetry, the magnet 5 is advantageously disposed eccentrically with respect to the exciter 6. Preferably, the magnet 5 adjoins one of the sides of the ferrite substrate 1. For example, when the antenna is of monopole type, the magnet 5 is preferably arranged in one of the four zones 51, 52, 53, 54, as illustrated in FIG. 26. When the antenna is of the semi-open type, the magnet 5 is preferably disposed at level of the area that forms the opening (reference 3 Figures 2 and 5). In this case, the magnet 5 is disposed in an eccentric zone 50, opposite the short-circuit 2 as illustrated in FIG. 27.
Dans l'exemple décrit ci-dessus en référence à la figure 1, l'aimant 5 recouvre environ 10,34% de la surface du substrat 1. Toutefois, l'aimant 5 peut aussi recouvrir la totalité de la surface du ferrite, auquel cas le diagramme de rayonnement n'est pas modifié mais l'antenne a une meilleure efficacité de rayonnement.  In the example described above with reference to FIG. 1, the magnet 5 covers approximately 10.34% of the surface of the substrate 1. However, the magnet 5 can also cover the entire surface of the ferrite, to which case the radiation pattern is not changed but the antenna has a better radiation efficiency.
Le ferrite dispersif sans modification locale des caractéristiques permet de stabiliser la variation de l'impédance de l'antenne et ainsi augmenter la bande passante de l'antenne, mais entraine une baisse de l'efficacité de rayonnement. La modification locale des caractéristiques permet de conserver cet avantage de stabilisation de la variation d'impédance et d'augmentation de bande passante tout en compensant la baisse de l'efficacité de rayonnement de sorte à obtenir une antenne performante.  The dispersive ferrite without local modification of the characteristics makes it possible to stabilize the variation of the impedance of the antenna and thus increase the bandwidth of the antenna, but causes a fall in the radiation efficiency. The local modification of the characteristics makes it possible to maintain this advantage of stabilizing the impedance variation and bandwidth increase while compensating for the fall in the radiation efficiency so as to obtain a high performance antenna.
La figure 9 est un graphique représentant sur une échelle logarithmique les pertes magnétiques, représentées par la tangente de pertes magnétiques dans le ferrite dispersif d'une antenne selon un mode de réalisation de l'invention, en fonction de la fréquence (en MHz sur une échelle logarithmique), en l'absence (courbe 0 G) ou en présence d'aimants ayant différentes valeurs d'induction magnétique (620 G, 1680 G et 2410 G). Les figures 10a et 10b sont des graphiques représentant respectivement la partie réelle et la partie imaginaire de la perméabilité magnétique relative dans le ferrite dispersif d'une antenne selon un mode de réalisation de l'invention en fonction de la fréquence (en MHz sur une échelle logarithmique), en l'absence (courbe 0 G) ou en présence d'aimants ayant différentes valeurs d'induction magnétique (620 G, 1680 G et 2410 G). Les résultats expérimentaux présentés sur les diagrammes des figures 9 et 10 ont été obtenus avec une ferrite NiZn, commercialement disponible sous référence la 4S60 et communément utilisée pour ses propriétés d'atténuation des ondes radio à des fréquences supérieures à 1 GHz. FIG. 9 is a graph representing on a logarithmic scale the magnetic losses, represented by the tangent of magnetic losses in the dispersive ferrite of an antenna according to one embodiment of the invention, as a function of frequency (in MHz over a logarithmic scale), in the absence (0 G curve) or in the presence of magnets having different magnetic induction values (620 G, 1680 G and 2410G). FIGS. 10a and 10b are graphs respectively representing the real part and the imaginary part of the relative magnetic permeability in the dispersive ferrite of an antenna according to one embodiment of the invention as a function of frequency (in MHz on a scale logarithmic), in the absence (0 G curve) or in the presence of magnets with different magnetic induction values (620 G, 1680 G and 2410 G). The experimental results presented in the diagrams of FIGS. 9 and 10 were obtained with NiSn ferrite, commercially available under reference 4S60 and commonly used for its attenuation properties of radio waves at frequencies higher than 1 GHz.
Des résultats similaires pourront être obtenus avec d'autres ferrites dispersifs, notamment des ferrites spinelles, présentant à la fois une forte perméabilité magnétique relative comprise entre 10 et 10000 et une haute tangente de perte magnétique supérieure à 0,1. On rappelle que la perméabilité magnétique relative et la tangente de perte magnétique dépendent non seulement du matériau mais également de la fréquence de travail de l'antenne considérée. Dans le cadre de la présente invention, la fréquence de travail reste inférieure à 300 MHz.  Similar results may be obtained with other dispersive ferrites, in particular spinel ferrites, having both a high relative magnetic permeability of between 10 and 10,000 and a high tangent of magnetic loss greater than 0.1. It is recalled that the relative magnetic permeability and the magnetic loss tangent depend not only on the material but also on the working frequency of the antenna considered. In the context of the present invention, the working frequency remains below 300 MHz.
Les parties réelles et imaginaires de la perméabilité magnétique relative sont communément désignées respectivement par les symboles μ' et μ".  The real and imaginary parts of the relative magnetic permeability are commonly designated respectively by the symbols μ 'and μ ".
La tangente de pertes magnétiques (souvent désignée par le symbole tan δ) est le rapport de la partie imaginaire sur la partie réelle de la perméabilité magnétique relative.  The tangent of magnetic losses (often designated by the symbol tan δ) is the ratio of the imaginary part to the real part of the relative magnetic permeability.
La tangente de pertes magnétiques et les parties réelles et imaginaires de la perméabilité magnétique relative sont mesurées dans le ferrite dispersif au niveau des zones où les caractéristiques magnétiques du ferrite dispersif sont modifiées.  The tangent of magnetic losses and the real and imaginary parts of the relative magnetic permeability are measured in the dispersive ferrite at the zones where the magnetic characteristics of the dispersive ferrite are modified.
Comme visible sur les graphiques, en présence d'un aimant, les pertes magnétiques et la perméabilité magnétique relative diminuent, permettant d'obtenir les effets sur le gain et le rayonnement décrit précédemment. Cette réduction est d'autant plus importante que la valeur de l'induction magnétique de l'aimant est importante.  As shown in the graphs, in the presence of a magnet, the magnetic losses and the relative magnetic permeability decrease, allowing to obtain the effects on the gain and radiation described above. This reduction is all the more important as the value of the magnetic induction of the magnet is important.
Sur les graphiques des figures 10a et 10b, la réduction de la perméabilité magnétique relative est particulièrement visible dans les fréquences entre 1 et 30 MHz, qui fait partie de la bande de fréquence visée par l'invention. Au-delà de 100 MHz, la perméabilité magnétique relative est faible dans tous les cas. In the graphs of FIGS. 10a and 10b, the reduction of the relative magnetic permeability is particularly visible in the frequencies between 1 and 30 MHz, which forms part of the frequency band targeted by the invention. Beyond 100 MHz, the Relative magnetic permeability is low in all cases.
Les ferrites spinelles dispersives, notamment NiZn, connues pour présenter une haute perméabilité magnétique sont généralement utilisées pour former des revêtements destinés à absorber les ondes électromagnétiques, en particulier les parois des chambres anéchoïdes opérant à des fréquences jusqu'à 1000 MHz. Dans le cadre de la présente invention, on utilise avantageusement ce type de ferrite.  Dispersive spinel ferrites, especially NiZn, known to exhibit high magnetic permeability are generally used to form coatings for absorbing electromagnetic waves, particularly the walls of anechoic chambers operating at frequencies up to 1000 MHz. In the context of the present invention, this type of ferrite is advantageously used.
Les figures lia, 11b et 11c représentent schématiquement du dessus des antennes selon différents modes de réalisation de l'invention, comprenant un aimant permanent. La forme des aimants peut être modifiée, entraînant ainsi une distribution différente du champ magnétique généré. Cette distribution différente entraine une modification du diagramme de rayonnement de l'antenne qui peut donc être adapté selon les besoins. Les formes représentées en exemple sont rectangulaires (figure lia), circulaires (figure 11b) ou triangulaires (figure 11c). Figures 11a, 11b and 11c show schematically from above antennas according to various embodiments of the invention, comprising a permanent magnet. The shape of the magnets can be modified, resulting in a different distribution of the magnetic field generated. This different distribution causes a modification of the radiation pattern of the antenna which can therefore be adapted as needed. The shapes shown as examples are rectangular (Figure 11a), circular (Figure 11b) or triangular (Figure 11c).
La figure 12 représente schématiquement du dessus une antenne selon un mode de réalisation de l'invention, comprenant un électroaimant 5. L'électroaimant peut remplacer un aimant permanent dans les différents modes de réalisation de l'antenne. L'électroaimant est alimenté par un générateur 9 de courant variable, permettant ainsi de modifier la valeur du champ magnétique qu'il génère. Il est ainsi possible d'influer sur des performances telles que les paramètres S de l'antenne, le gain et la forme du diagramme de rayonnement.  FIG. 12 schematically shows from above an antenna according to one embodiment of the invention, comprising an electromagnet 5. The electromagnet can replace a permanent magnet in the various embodiments of the antenna. The electromagnet is powered by a generator 9 of variable current, thereby changing the value of the magnetic field it generates. It is thus possible to influence performances such as the parameters S of the antenna, the gain and the shape of the radiation diagram.
La figure 13 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le premier mode de réalisation de l'invention en l'absence (courbe 0 G) ou en présence d'aimants ayant différentes valeurs d'induction magnétique (780 G, 850 G, 1430 G), par exemple d'un électro-aimant, en fonction de la fréquence (en MHz). Le coefficient de réflexion Su permet de déterminer l'adaptation d'impédance de l'antenne. À l'aide de l'aimant adapté ou par réglage avec un électro-aimant, il est ainsi possible de choisir la valeur du champ magnétique de sorte à avoir l'adaptation d'impédance souhaitée, par exemple 50 Ω.  FIG. 13 is a graph representing the reflection coefficient Su of an antenna according to the first embodiment of the invention in the absence (0 G curve) or in the presence of magnets having different magnetic induction values (780). G, 850 G, 1430 G), for example an electromagnet, depending on the frequency (in MHz). The reflection coefficient Su makes it possible to determine the impedance matching of the antenna. With the aid of the magnet adapted or by adjustment with an electromagnet, it is thus possible to choose the value of the magnetic field so as to have the desired impedance matching, for example 50 Ω.
La figure 14 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le premier mode de réalisation de l'invention en l'absence (courbe SA pour « sans aimant ») ou en présence (courbe AA pour « avec aimant ») d'un aimant permanent de 2000 G, en fonction de la fréquence (en MHz). L'antenne est ici de type monopôle. FIG. 14 is a graph representing the reflection coefficient S u of an antenna according to the first embodiment of the invention in the absence (SA curve for "without magnet") or in the presence (curve AA for "with magnet") of a permanent magnet of 2000 G, depending on the frequency (in MHz). The antenna is here of monopole type.
La figure 15 est un graphique représentant le coefficient de réflexion Su d'une antenne selon le deuxième mode de réalisation de l'invention en l'absence (courbe SA) ou en présence (courbe AA) d'un aimant permanent de 2000 G, en fonction de la fréquence (en MHz). L'antenne est ici de type semi-ouverte. FIG. 15 is a graph representing the reflection coefficient S u of an antenna according to the second embodiment of the invention in the absence (curve SA) or in the presence (curve AA) of a permanent magnet of 2000 G , depending on the frequency (in MHz). The antenna is here semi-open type.
La figure 16 est un diagramme de rayonnement d'une antenne selon le premier mode de réalisation de l'invention en l'absence (courbe SA) ou en présence (courbe AA) d'un aimant permanent de 2000 G.  FIG. 16 is a radiation diagram of an antenna according to the first embodiment of the invention in the absence (SA curve) or in the presence (AA curve) of a 2000 G permanent magnet.
L'antenne sans aimant est une antenne omnidirectionnelle de faible gain, tandis que l'antenne de type monopôle avec un aimant selon l'invention est directionnelle et a un gain plus important dans toutes les directions. La figure 17 est un diagramme de rayonnement d'une antenne selon le deuxième mode de réalisation de l'invention en l'absence (courbe SA) ou en présence (courbe AA) d'un aimant permanent de 2000 G.  The antenna without magnet is a low gain omnidirectional antenna, while the monopole antenna with a magnet according to the invention is directional and has a greater gain in all directions. FIG. 17 is a radiation diagram of an antenna according to the second embodiment of the invention in the absence (curve SA) or in the presence (curve AA) of a permanent magnet of 2000 G.
L'antenne sans aimant est une antenne directionnelle de faible gain, tandis que l'antenne semi-ouverte avec un aimant selon l'invention a un diagramme sensiblement similaire mais présente un gain plus important dans toutes les directions.  The antenna without magnet is a directional antenna of low gain, while the semi-open antenna with a magnet according to the invention has a substantially similar diagram but has a greater gain in all directions.
De manière générale, le diagramme de rayonnement de l'antenne tel que représenté aux figure 16 et 17 peut être également ajusté en fonction de la position relative de l'aimant 5 par rapport au substrat 1.  In general, the radiation pattern of the antenna as shown in FIGS. 16 and 17 can also be adjusted as a function of the relative position of the magnet 5 with respect to the substrate 1.
Les figures 18a, 18b et 18c sont des vues schématiques du dessus du ferrite dispersif d'antennes selon différents modes de réalisation de l'invention, comprenant une pièce insérée.  Figures 18a, 18b and 18c are schematic top views of the antenna dispersive ferrite according to various embodiments of the invention, comprising an insert.
Les pièces 10 insérées sont des pièces de matériau ayant une faible perméabilité magnétique relative et de faibles pertes magnétiques insérées dans le ferrite dispersif et qui entraînent une réduction graduelle et locale de la perméabilité magnétique et des pertes magnétiques du ferrite dispersif.  The inserted pieces are pieces of material having a low relative magnetic permeability and low magnetic losses inserted into the dispersive ferrite and which result in a gradual and local reduction in the magnetic permeability and magnetic losses of the dispersive ferrite.
Par faible perméabilité magnétique relative, on comprend des valeurs de perméabilité magnétique relative inférieure à 10. Par faibles pertes magnétiques, on comprend des valeurs de tangente de perte magnétique inférieures à 0,1. Comme indiqué ci-avant, ces valeurs sont à considérer à la fréquence de travail de l'antenne, c'est-à-dire à une fréquence comprise dans une bande de fréquences sur laquelle l'adaptation d'impédance de l'antenne est réalisée. By low relative magnetic permeability, relative magnetic permeability values less than 10 are understood. By low magnetic losses, magnetic loss tangent values of less than 0.1 are included. As indicated above, these values are to be considered at the working frequency of the antenna, that is to say at a frequency included in a frequency band on which the impedance matching of the antenna is carried out .
La ou les pièces 10 insérées peuvent prendre la place de l'aimant (permanent ou électroaimant) dans tous les modes de réalisation de l'antenne décrits précédemment. Comme l'aimant, elles peuvent prendre différentes formes comme par exemple celles présentées sur les figures 18a, 18b et 18c. Les figures sont similaires aux figures lia, 11b et 11c mais les pièces 10 sont ici insérées dans le ferrite 1 dispersif au lieu d'être disposées au-dessus sur une plaque métallique (comme l'aimant). Les zones hachurées représentées peuvent être composées d'une seule pièce insérée en un bloc ou de plusieurs pièces insérées agencées côte à côte. Différentes pièces insérées peuvent avoir des perméabilités et/ou tangente de pertes différentes (toujours plus faibles que le ferrite 1 dispersif).  The inserted part (s) 10 can take the place of the magnet (permanent or electromagnet) in all the embodiments of the antenna described above. Like the magnet, they can take different forms, for example those shown in FIGS. 18a, 18b and 18c. The figures are similar to Figures 11a, 11b and 11c but the parts 10 are here inserted into the dispersive ferrite 1 instead of being arranged above on a metal plate (like the magnet). The hatched areas shown may be composed of a single piece inserted into a block or of several inserted pieces arranged side by side. Different inserted parts may have permeabilities and / or tangent of different losses (always lower than the dispersive ferrite 1).
Comme pour l'aimant, les formes peuvent agir sur les caractéristiques de l'antenne, notamment sa directivité.  As for the magnet, the shapes can affect the characteristics of the antenna, especially its directivity.
La figure 19 représente schématiquement en perspective une antenne dite empilée selon un quatrième mode de réalisation de l'invention. FIG. 19 diagrammatically shows in perspective a so-called stacked antenna according to a fourth embodiment of the invention.
Une antenne empilée selon l'invention comprend plusieurs ferrites dispersifs et plusieurs aimants empilés entre le plan de masse et au moins une plaque en métal de la partie rayonnante.  A stacked antenna according to the invention comprises a plurality of dispersive ferrites and several magnets stacked between the ground plane and at least one metal plate of the radiating portion.
Dans ce quatrième mode de réalisation de l'invention, la partie rayonnante 4H est formée de plusieurs plaques en métal reliées en S ou en zigzag, entre lesquelles se situent alternativement un ferrite dispersif ou un aimant, de sorte qu'il y ait autant de ferrites dispersifs que d'aimants. Par exemple, ici, l'antenne comprend deux ferrites 11 et 12 dispersifs et deux aimants 51 et 52 permanents. La partie 4H rayonnante est reliée au plan 4B par un court-circuit 2. L'excitateur 6 traverse toutes les ferrites et aimants et ne touche que la plaque supérieure de la partie 4H rayonnante. In this fourth embodiment of the invention, the radiating portion 4 H is formed of several metal plates connected in S or zigzag, between which are alternately a dispersive ferrite or a magnet, so that there is as much of dispersive ferrites than magnets. For example, here, the antenna comprises two ferrites 1 1 and 1 2 dispersive and two magnets 5 1 and 5 2 permanent. The radiant 4 H part is connected to the plane 4 B by a short-circuit 2. The exciter 6 passes through all the ferrites and magnets and touches only the top plate of the radiating part 4 H.
La figure 20 représente schématiquement en perspective une antenne dite empilée selon un cinquième mode de réalisation de l'invention.  FIG. 20 diagrammatically shows in perspective a so-called stacked antenna according to a fifth embodiment of the invention.
L'antenne de ce mode de réalisation est identique au quatrième mode de réalisation, sauf que l'excitateur est déporté à la place du court-circuit et alimente l'antenne entre le plan 4B de masse et la plaque de la partie 4H qui est la plus proche du plan 4B de masse. The antenna of this embodiment is identical to the fourth mode of realization, except that the exciter is deported instead of the short circuit and feeds the antenna between the ground plane 4 B and the plate of the part 4 H which is closest to the plane 4 B ground.
La figure 21 représente schématiquement en perspective une antenne dite empilée selon un sixième mode de réalisation de l'invention.  FIG. 21 diagrammatically shows in perspective a so-called stacked antenna according to a sixth embodiment of the invention.
L'antenne de ce mode de réalisation est identique au quatrième mode de réalisation, sauf qu'elle ne comprend pas de court-circuit 2.  The antenna of this embodiment is identical to the fourth embodiment, except that it does not include a short-circuit 2.
La figure 22 représente schématiquement en perspective une antenne dite empilée selon un septième mode de réalisation de l'invention.  FIG. 22 diagrammatically shows in perspective an antenna said to be stacked according to a seventh embodiment of the invention.
Dans ce mode de réalisation, l'antenne comprend une seule plaque de métal formant la partie 4H rayonnante, et entre la partie 4H rayonnante et le plan 4B de masse se trouve un empilement de ferrites dispersifs et d'aimants alternés, ici deux ferrites 11 et 12 dispersifs et deux aimants 51 et 52 permanents. In this embodiment, the antenna comprises a single metal plate forming the radiating part 4 H , and between the radiating part 4 H and the ground plane 4 B is a stack of dispersive ferrites and alternating magnets, here two ferrites 1 1 and 1 2 dispersive and two magnets 5 1 and 5 2 permanent.
La figure 23 représente schématiquement en perspective une antenne dite empilée selon un huitième mode de réalisation de l'invention.  FIG. 23 diagrammatically shows in perspective an antenna said stacked according to an eighth embodiment of the invention.
Dans ce mode de réalisation, l'antenne comprend plusieurs plaques métalliques 4m, 4H2, 4H3 et 4H4 formant la partie rayonnante. Chaque plaque métallique est reliée à l'excitateur 6. Entre le plan 4B de masse et la plaque 4H4 se trouve un ferrite 12 dispersif, entre la plaque 4H4 et la plaque 4H3 se trouve un aimant 52, entre la plaque 4H3 et la plaque 4H2 se trouve un ferrite 11 dispersif et entre la plaque 4H2 et la plaque AH1 se trouve un aimant 5i. In this embodiment, the antenna comprises a plurality of metal plates 4m, 4H 2 , 4H 3 and 4H 4 forming the radiating portion. Each metal plate is connected to the exciter 6. Between the plane 4 B of mass and the plate 4 H4 is a ferrite 1 2 dispersive, between the plate 4 H4 and the plate 4 H3 is a magnet 5 2 , between the plate 4 H3 and the plate 4 H2 is a dispersive ferrite 1 1 and between the plate 4 H2 and the plate A H1 is a magnet 5i.
La figure 24 représente schématiquement en perspective une antenne dite empilée selon un neuvième mode de réalisation de l'invention.  FIG. 24 diagrammatically shows in perspective an antenna said to be stacked according to a ninth embodiment of the invention.
L'antenne de ce mode de réalisation est similaire au huitième mode de réalisation, en ce qu'il contient une pluralité de plaq ues métalliques 4m, 4 2, 4 3, 4 4, 4 4 4 et 4 de forme circulaire, formant la partie rayonnante et reliées à l'excitateur 6. Entre les plaques métalliques se trouvent alternativement un ferrite llt 12, 13 ou 14 dispersive de forme circulaire ou un aimant 51( 52, 53 ou 54 de forme circulaire. The antenna of this embodiment is similar to the eighth embodiment, in that it contains a plurality of metal plates 4m, 4 2 , 4 3 , 4 4 , 4 4 4 and 4 of circular shape, forming the the radiating part and connected to the exciter 6. Between the metal plates are alternately a ferrite l lt 1 2 , 1 3 or 1 4 dispersive circular or a magnet 5 1 ( 5 2 , 5 3 or 5 4 circular shape .
La figure 25 représente schématiquement en perspective une antenne dite empilée selon un neuvième mode de réalisation de l'invention.  FIG. 25 diagrammatically shows in perspective an antenna said to be stacked according to a ninth embodiment of the invention.
L'antenne de ce mode de réalisation est similaire au premier mode de réalisation en ce qu'il comprend un aimant disposé sur la partie rayonnante 4H de l'antenne, celle-ci étant séparée du plan de masse 4B par le substrat de ferrite dispersif 1. The antenna of this embodiment is similar to the first mode of embodiment in that it comprises a magnet disposed on the radiating part 4H of the antenna, the antenna being separated from the ground plane 4B by the dispersive ferrite substrate 1.
Selon une particularité de ce mode de réalisation, la deuxième plaque formant la partie rayonnante 4H est découpée de manière à former une spirale plate rectangulaire. Par exemple, cette spirale est centrée sur l'excitateur 6 de l'antenne.  According to a feature of this embodiment, the second plate forming the radiating portion 4H is cut to form a rectangular flat spiral. For example, this spiral is centered on the exciter 6 of the antenna.
L'invention ne se limite pas aux seuls modes de réalisation décrits. En particulier, les ferrites dispersifs, les aimants, les pièces insérées ou les plaques en métal peuvent prendre des formes différentes. Les aimants peuvent présenter des valeurs différentes de celles indiquées dans les graphiques. Les antennes empilées peuvent contenir davantage de couches.  The invention is not limited to the embodiments described. In particular, dispersive ferrites, magnets, inserted parts or metal plates can take different forms. Magnets may have different values from those shown in the graphs. Stacked antennas may contain more layers.

Claims

REVENDICATIONS
1. Antenne adaptée à recevoir ou émettre à au moins une fréquence de travail comprise dans une bande de fréquences kilométriques (30-300 kHz), hectométriques (0,3-3 MHz), décamétriques (3-30 M Hz) et métriques (30-300 M Hz), comprenant : Antenna suitable for receiving or transmitting at at least one working frequency within a frequency band of 30-300 kHz, MF (0.3-3 MHz), HF (3-30 MHz) and metric frequency ( 30-300 M Hz), comprising:
au moins deux plaques en métal non ferreux s'étendant principalement selon un plan horizontal, au moins une première plaque formant une partie (4H ; , 4H2, 4H3, 4H4 ; 4H1, 4H2, 4H3, 4H4, 4H5, 4H6, 4H7, 4H8) rayonnante et une deuxième plaque formant un plan (4B) de masse, - au moins un substrat (1 ; llt 12 ; li, 12, I3, I4) s'étendant principalement selon un plan horizontal, disposé entre le plan (4B) de masse et la partie (4H) rayonnante, at least two plates made of nonferrous metal extending mainly in a horizontal plane, at least a first plate forming a portion (4 H;, 4 H2, H3 4, 4 H4; 4 H1, H2 4, 4 H3, H4 4 , 4 H5, 4 H6, 4 H7, 4 H8) radiating and a second plate forming a plane (4B) of mass, - at least one substrate (1; l lt 1 2; li, 1 2, I3, I4) extending mainly in a horizontal plane, disposed between the ground plane (4 B ) and the radiating portion (4 H ),
un excitateur (6) de longueur au moins égale à l'épaisseur du substrat, s'étendant entre le plan (4B) de masse et la partie (4H) rayonnante et relié à la partie (4H) rayonnante, et adapté pour alimenter l'antenne, ladite antenne étant caractérisée en ce que le substrat est un substrat ferromagnétique dispersif, dit ferrite (1) dispersif, présentant à ladite au moins une fréquence de travail comme caractéristiques magnétiques une haute perméabilité magnétique relative comprise entre 10 et 10000 et une haute tangente de pertes magnétiques supérieure à 0,1, ladite antenne comprenant des moyens de modification locale (5 ; 51( 52 ; 51( 52, 53, 54 ; 10) des caractéristiques magnétiques du ferrite (1 ; llt 12 ; llt 12, 13, 14) dispersif, de sorte à ce que la perméabilité magnétique relative et les pertes magnétiques du ferrite dispersif soient réduites graduellement et localement. an exciter (6) of length at least equal to the thickness of the substrate, extending between the plane (4 B ) of mass and the portion (4 H ) radiating and connected to the portion (4 H ) radiating, and adapted for feeding the antenna, said antenna being characterized in that the substrate is a dispersive ferromagnetic substrate, said ferrite (1) dispersive, having at said at least one working frequency as magnetic characteristics a high relative magnetic permeability of between 10 and 10000 and a high tangent of magnetic losses greater than 0.1, said antenna comprising means for locally modifying (5; 5 1 ( 5 2 ; 5 1 ( 5 2 , 5 3 , 5 4 ; 10) magnetic characteristics of the ferrite ( 1; l lt 1 2; l lt 1 2, 1 3, 1 4) dispersive, so that the relative magnetic permeability and magnetic losses in the ferrite dispersive be reduced gradually and locally.
2. Antenne selon la revendication 1, caractérisée en ce que les moyens de modification locale (5 ; 5Χ, 52 ; 5Χ, 52, 53, 54 ; 10) des caractéristiques magnétiques du ferrite dispersif (1 ; llt 12 ; 1 12, 13, 14) sont un aimant (5 ; 5 52 ; 5 52, 53, 54 ) disposé sur une des plaques en métal non ferreux (4B ; 4H ; 4Hi, 4H2, 4H3, 4H4 ; 4Hi, 4H2, 4H3, 4H4, 4H5, 4H6, 4H7, 4H8) et générant un champ magnétique entraînant une réduction graduelle et locale de la perméabilité magnétique relative et des pertes magnétiques du ferrite dispersif. 2. Antenna according to claim 1, characterized in that the local modification means (5; 5 Χ , 5 2 ; 5 Χ , 5 2 , 5 3 , 5 4 ; 10) of the magnetic characteristics of the dispersive ferrite (1; lt 1 2; 1 1 2, 1˝ 3, 1 4) are a magnet (5; 5 5 2; 5 5 2, 5 3, 5 4) arranged on a non-ferrous metal plates (4 B, 4 H; 4 M i, 4 H2, 4 H3, 4 H4; 4 H i, 4 H2, 4 H3, 4 H4, 4 H5, 4H6, 4 H7, 4 H 8) and generating a magnetic field resulting in a gradual and local reduction of relative magnetic permeability and magnetic losses of dispersive ferrite.
3. Antenne selon la revendication 2, caractérisé en ce que l'aimant (5) est disposé sur ladite au moins une première plaque formant une partie rayonnante (4H ; H1, 4H2, 4H3, H4 ; 4Hi, 4h2, 4h3, 4H4, 4H5, 4h6, 4H7, 4h8) de l'antenne. 3. Antenna according to claim 2, characterized in that the magnet (5) is disposed on said at least one first plate forming a radiating part (4 H ; H1 , 4 H2 , 4 H3 , H4 ; 4 H i, 4 h2, h3 4, 4 H4, H5 4, 4 h6, H7 4, 4 h8) of the antenna.
4. Antenne selon la revendication 2, caractérisée en ce que l'aimant (5 ; 5i, 52 ; 5 52, 53, 54) est un aimant permanent. 4. Antenna according to claim 2, characterized in that the magnet (5; 5i, 5 2 ; 5 2 , 5 3 , 5 4 ) is a permanent magnet.
5. Antenne selon la revendication 2, caractérisée en ce que l'aimant est un électroaimant, alimenté par un générateur (9) électrique de courant continu variable. 5. Antenna according to claim 2, characterized in that the magnet is an electromagnet, powered by a generator (9) electric DC variable.
6. Antenne selon l'une des revendications 2 à 4, caractérisée en ce qu'elle comprend une succession de ferrite dispersif (11( 12 ; llt 12, 13, 14) et d'aimant (51( 52 ; 51( 52, 53, 54) empilés alternativement entre la partie rayonnante (4H ; 4Hi, 4H2, 4H3, 4H4 ; 4Hi, 4H2, 4H3, 4H4, 4H5, 4H6, 4H7, 4H8) et le plan de masse (4B). 6. Antenna according to one of Claims 2 to 4, characterized in that it comprises a dispersive ferrite succession (1 1 (1 2; l lt 1 2, 1 3, 1 4) and magnet (5 1 (5 2; May 1 (5 2, 5 3, 5 4) alternately stacked between the radiating part (4 H, 4 H i, 4 H2, 4 H3, 4 H4; 4 H i, 4 H2, 4 H3, 4 H4 , 4H5 , 4H6 , 4H7 , 4H8 ) and the ground plane ( 4B ).
7. Antenne selon la revendication 5, caractérisée en ce que la partie rayonnante comprend une plaque en métal (4H2, 4H3, 4H4 ; 4H2, 4H3, 4H4, 4H5, 4H6, 4H7, 4H8) entre chaque ferrite (11( 12 ; 11( 12, 13, 14) et aimant (51( 52). 7. Antenna according to Claim 5, characterized in that the radiating portion includes a metal plate (4 H2, H3 4, 4 H4; 4 H2, H3 4, 4 H4, H5 4, 4 H6, 4 H7, H8 4 ) between each ferrite (1 1 ( 1 2 ; 1 1 ( 1 2 , 1 3 , 1 4 ) and magnet (5 1 ( 5 2 ).
8. Antenne selon la revendication 6, caractérisée en ce que les plaques de métal sont reliées entre elles. 8. Antenna according to claim 6, characterized in that the metal plates are interconnected.
9. Antenne selon la revendication 1, caractérisée en ce que les moyens de modification locale des caractéristiques magnétiques du ferrite (1) dispersif sont au moins une pièce (10) de matériau ayant une faible perméabilité magnétique relative et une faible tangente de pertes insérée dans le ferrite dispersif et entraînant une réduction graduelle et locale de la perméabilité magnétique et des pertes magnétiques du ferrite dispersif. 9. Antenna according to claim 1, characterized in that the means for locally modifying the magnetic characteristics of the dispersive ferrite (1) are at least one piece (10) of material having a relatively low magnetic permeability and a small loss tangent inserted in dispersive ferrite and resulting in gradual and local reduction of magnetic permeability and magnetic losses of dispersive ferrite.
10. Antenne selon l'une des revendications 1 à 7, caractérisée en ce que le ferrite (1) dispersif présente un encombrement dans le plan horizontal supérieur à l'encombrement des plaques en métal. 10. Antenna according to one of claims 1 to 7, characterized in that the ferrite (1) dispersive has a size in the horizontal plane greater than the size of the metal plates.
11. Antenne selon l'une des revendications 1 à 8, caractérisée en ce qu'elle comprend au moins un court-circuit (2) reliant le plan (4B) de masse et la partie (4H) rayonnante, en contact avec un contour du ferrite (1) dispersif. 11. Antenna according to one of claims 1 to 8, characterized in that it comprises at least one short-circuit (2) connecting the plane (4 B ) ground and the portion (4 H ) radiating, in contact with an outline of the dispersive ferrite (1).
EP18793251.2A 2017-10-04 2018-10-04 Antenna with partially saturated dispersive ferromagnetic substrate Active EP3692598B1 (en)

Applications Claiming Priority (2)

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FR1759284A FR3071968B1 (en) 2017-10-04 2017-10-04 PARTIALLY SATURATED DISPERSIVE FERROMAGNETIC SUBSTRATE ANTENNA
PCT/FR2018/052456 WO2019069033A1 (en) 2017-10-04 2018-10-04 Antenna with partially saturated dispersive ferromagnetic substrate

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CN (1) CN111183552B (en)
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US5327148A (en) * 1993-02-17 1994-07-05 Northeastern University Ferrite microstrip antenna
US5502451A (en) * 1994-07-29 1996-03-26 The United States Of America As Represented By The Secretary Of The Air Force Patch antenna with magnetically controllable radiation polarization
US6677901B1 (en) * 2002-03-15 2004-01-13 The United States Of America As Represented By The Secretary Of The Army Planar tunable microstrip antenna for HF and VHF frequencies
JP2005080023A (en) * 2003-09-01 2005-03-24 Sony Corp Magnetic core member, antenna module and portable communication terminal provided with the same
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JP2007067994A (en) * 2005-09-01 2007-03-15 Sony Corp Antenna
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IT1398678B1 (en) * 2009-06-11 2013-03-08 Mbda italia spa SLOT SLIP ANTENNA WITH POWER SUPPLY IN WAVE GUIDE AND PROCEDURE FOR REALIZING THE SAME
WO2014134054A1 (en) * 2013-02-26 2014-09-04 The Board Of Trustees Of The University Of Alabama For And On Behalf Of The University Of Alabama Antenna modules having ferrite substrates
KR20160014938A (en) * 2014-07-30 2016-02-12 삼성전기주식회사 Magneto-dielectric antenna
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WO2019069033A1 (en) 2019-04-11
US20200235473A1 (en) 2020-07-23
IL273692B2 (en) 2023-07-01
FR3071968A1 (en) 2019-04-05
FR3071968B1 (en) 2020-11-27
IL273692B1 (en) 2023-03-01
IL273692A (en) 2020-05-31
CN111183552A (en) 2020-05-19
ES2926348T3 (en) 2022-10-25
US11114761B2 (en) 2021-09-07
CN111183552B (en) 2022-02-18
EA202090664A1 (en) 2020-07-22

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