EP4167378A1 - Insulated radio frequency antenna device - Google Patents

Abstract

Radio frequency device (1) comprising a first set of antennas (2) comprising a first antenna (2a) and a second antenna (2b), the first antenna and the second antenna being flat in shape and both extending in the same first plane (3), the first antenna being arranged to operate in a first frequency band, the second antenna being arranged to operate in a second frequency band; a first insulator (5), the first insulator being planar in shape and extending in the first plane (3) between the first antenna (2a) and the second antenna (2b), the first insulator (5) comprising at least one branch which is electrically conductive, the first insulator being electrically floating, the first insulator being arranged to reduce a first coupling by electromagnetic radiation, between the first antenna (2a) and the second antenna (2b), on the first frequency band and/ or the second frequency band.

Description

The invention relates to the field of radio frequency devices comprising a plurality of antennas. The invention applies in particular when the antennas operate in adjacent or even similar frequency bands.

BACKGROUND OF THE INVENTION

Some recent electrical equipment, for example residential gateways , comprise a plurality of antennas in order to transmit and receive radio frequency signals in different frequency bands. To limit interference between the antennas, it is necessary to ensure that said antennas are properly isolated from each other. This is particularly critical when the frequency bands used in the same equipment are adjacent (for example 5GHz Wi-Fi and 6GHz Wi-Fi), or even similar.

It is known to integrate filtering means, comprising for example analog electronic components, in the transmission chain and the reception chain of radio frequency signals. However, such a solution has an impact on the radio frequency signals transmitted or received regardless of their direction of propagation. Moreover, this solution is generally inefficient when the frequency bands are adjacent.

Diversity techniques are also known, for example spatial diversity, polarization diversity or radiation diversity. Nevertheless, the performances of these techniques are generally limited when they are implemented in a compact equipment. In particular, they do not make it possible to ensure a omnidirectional propagation of radiofrequency signals in multiple-input multiple - output (MIMO) radiofrequency systems exploiting adjacent frequency bands.

It is also known to create insulating elements such as screens, reflectors or absorbers from one or more metal parts. However, the insulating elements thus created perform poorly when integrated into a compact device.

OBJECT OF THE INVENTION

An object of the invention is to propose a compact radiofrequency device meeting the insulation constraints set out above when adjacent frequency bands are used.

SUMMARY OF THE INVENTION

• un premier ensemble d'antennes comprenant une première antenne et une deuxième antenne, la première antenne et la deuxième antenne étant de formes planes et s'étendant toutes deux dans un même premier plan, la première antenne étant agencée pour opérer dans une première bande de fréquences, la deuxième antenne étant agencée pour opérer dans une deuxième bande de fréquences ;
• un premier isolateur, le premier isolateur étant de forme plane et s'étendant dans le premier plan entre la première antenne et la deuxième antenne, le premier isolateur comportant au moins une branche qui est électriquement conductrice, le premier isolateur étant électriquement flottant, le premier isolateur étant agencé pour réduire un premier couplage par rayonnement électromagnétique, entre la première antenne et la deuxième antenne, sur la première bande de fréquences et/ou la deuxième bande de fréquences.

With a view to achieving this object, a radio frequency device is proposed comprising:

• a first set of antennas comprising a first antenna and a second antenna, the first antenna and the second antenna being planar in shape and both extending in the same first plane, the first antenna being arranged to operate in a first band of frequencies, the second antenna being arranged to operate in a second frequency band;
• a first insulator, the first insulator being planar in shape and extending in the first plane between the first antenna and the second antenna, the first insulator having at least one leg which is electrically conductive, the first insulator being electrically floating, the first isolator being arranged to reduce a first coupling by electromagnetic radiation, between the first antenna and the second antenna, on the first frequency band and/or the second frequency band.

The radio frequency device according to the invention is particularly advantageous, because the arrangement of the first antenna and of the second antenna, as well as the configuration of the first insulator which is not electrically connected to a ground plane between said antennas, ensure that the radiofrequency device is compact while meeting the insulation constraints set out above.

According to a particular embodiment, the first frequency band and the second frequency band are separated by a frequency difference between 0 MHz and 1 GHz.

According to a particular embodiment, the first set of antennas and the first insulator are positioned on a support made of a dielectric material, the support extending along the first plane.

According to a particular embodiment, the first insulator comprises a first branch and a second branch, both of which are electrically conductive, the second branch being substantially perpendicular to the first branch and extending from a central portion of the first branch, a free end of the second branch being in open circuit, the first insulator thus having a “T” shape.

According to a particular embodiment, the first antenna and the second antenna are planar dipole antennas each having a rectangular shape, the first antenna being arranged to generate a first maximum electric field on a first axis, the second antenna being arranged to generate a second electric field maximum on a second axis, the first axis and the second axis being substantially parallel to each other.

According to a particular embodiment, the first axis and the second axis are oriented substantially at 45 degrees with respect to the second branch.

According to a particular embodiment, the first axis and the second axis are substantially perpendicular to the second branch.

According to a particular embodiment, the first maximum electric field is greater than the second maximum electric field, one end of the first branch of the first insulator being positioned at a distance of between 5 millimeters and 1.5 centimeters from the first axis.

où ν₁ est une première fréquence centrale centrée entre une fréquence maximale et une fréquence minimale de la première bande de fréquences, et εr est la permittivité diélectrique d'un milieu dans lequel s'étend le premier isolateur, le milieu étant un support diélectrique ou l'air.According to a particular embodiment, the first isolator is arranged to reduce the first coupling by electromagnetic radiation more significantly on the first frequency band, the first branch of the first isolator having a predefined length substantially equal to at least a quarter of a first wavelength λ _A , the first wavelength λ _A being such that: $${\lambda }_{\mathrm{AT}}=\frac{\mathrm{<figure-callout\; id="1"\; label="VS\; \nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">VS</figure-callout>}}{{\nu }_{}}$$

where ν ₁ is a first central frequency centered between a maximum frequency and a minimum frequency of the first frequency band, and εr is the dielectric permittivity of a medium in which the first insulator extends, the medium being a dielectric support or the air.

où ν₁ est une première fréquence centrale centrée entre une fréquence maximale et une fréquence minimale de la première bande de fréquences, ν₂ est une deuxième fréquence centrale centrée entre une fréquence maximale et une fréquence minimale de la deuxième bande de fréquences et εr est la permittivité diélectrique d'un milieu dans lequel s'étend le premier isolateur, le milieu étant un support diélectrique ou l'air.According to a particular embodiment, the first isolator is arranged to reduce the first coupling by electromagnetic radiation equally on the first frequency band and on the second frequency band, the first branch of the first isolator having a length predefined substantially equal to at least a quarter of a first wavelength λ _A , the first wavelength λ _A being such that: $${\lambda }_{\mathrm{AT}}=\frac{\mathrm{vs}}{\frac{{\mathrm{<figure-callout\; id="1"\; label="\nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="\nu "\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_2}{2}\times \sqrt{\mathit{\epsilon r}}}$$

where ν ₁ is a first center frequency centered between a maximum frequency and a minimum frequency of the first frequency band, ν ₂ is a second center frequency centered between a maximum frequency and a minimum frequency of the second frequency band and εr is the dielectric permittivity of a medium in which the first insulator extends, the medium being a dielectric support or air.

According to a particular embodiment, the second branch of the first insulator has a predefined length substantially equal to a quarter of the first wavelength λA.

According to a particular embodiment, the first branch of the first insulator has a predefined width so that the characteristic impedance of said first branch is substantially equal to the characteristic impedance of an antenna selected from among the first antenna and the second antenna, the second branch of the first insulator having a predefined width so that the characteristic impedance of said second branch is substantially equal to the characteristic impedance of the antenna selected from among the first antenna and the second antenna.

According to a particular embodiment, the first branch of the first insulator has a predefined width so that the characteristic impedance of said first branch is substantially between 75Ω and 120Ω, the second branch of the first insulator having a predefined width so that the characteristic impedance of said second branch is substantially between 75Ω and 120Ω.

According to a particular embodiment, the first insulator comprises three branches, all three of which are electrically conductive and arranged in such a way that said first insulator has a "Y" shape.

According to a particular embodiment, the radiofrequency device as previously described comprises at least a second insulator comprising at least one electrically conductive branch, the second insulator being electrically floating, the second insulator being positioned on one side of a particular antenna among the first antenna or the second antenna, said side of the particular antenna being opposite the first insulator, the second insulator being arranged to correct a change in directivity of the particular antenna caused by the presence of the first insulator.

According to a particular embodiment, the second insulator comprises a single electrically conductive branch, said insulator thus having a longitudinal shape.

According to a particular embodiment, the radiofrequency device as previously described comprises a third antenna extending in a second plane, the second isolator also being arranged to reduce a second coupling by electromagnetic radiation between the third antenna and the particular antenna , on a particular frequency band in which the particular antenna operates and on a third frequency band in which the third antenna operates.

où ν_# est une fréquence centrale particulière centrée entre une fréquence maximale et une fréquence minimale de la bande de fréquences particulière, et εr est la permittivité diélectrique d'un milieu dans lequel s'étend le deuxième isolateur, le milieu étant un support diélectrique ou l'air.According to a particular embodiment, the second insulator is arranged to reduce the second coupling by electromagnetic radiation more significantly on the particular frequency band, the branch of the second insulator having a predefined length substantially equal to half of a second wavelength λ _B , the second wavelength λ _B being such that: $${\lambda }_B=\frac{\mathrm{vs}}{{\nu }_{\#}\times \sqrt{\mathit{\epsilon r}}}$$

where ν _# is a particular center frequency centered between a maximum frequency and a minimum frequency of the particular frequency band, and εr is the dielectric permittivity of a medium in which the second insulator extends, the medium being a dielectric support or the air.

où ν_# est une fréquence centrale particulière centrée entre une fréquence maximale et une fréquence minimale de la bande de fréquences particulière, ν₃ est une troisième fréquence centrale centrée entre une fréquence maximale et une fréquence minimale de la troisième bande de fréquences et εr est la permittivité diélectrique d'un milieu dans lequel s'étend le deuxième isolateur, le milieu étant un support diélectrique ou l'air.According to a particular embodiment, the second isolator is arranged to reduce the second coupling by electromagnetic radiation equally on the particular frequency band and on the third frequency band, the branch of the second isolator having a predefined length substantially equal to at least half of a second wavelength λ _B , the second wavelength λ _B being such that: $${\lambda }_B=\frac{\mathrm{vs}}{\frac{{\nu }_{\#}+{\mathrm{<figure-callout\; id="3"\; label="\nu "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_3}{2}+\sqrt{\mathit{\epsilon r}}}$$

where ν _# is a particular center frequency centered between a maximum frequency and a minimum frequency of the particular frequency band, ν ₃ is a third center frequency centered between a maximum frequency and a minimum frequency of the third frequency band and εr is the dielectric permittivity of a medium in which the second insulator extends, the medium being a dielectric support or air.

According to a particular embodiment, the branch of the second insulator has a predefined width so that the characteristic impedance of said branch is substantially equal to the characteristic impedance of an antenna selected from the particular antenna and the third antenna.

According to a particular embodiment, the branch of the first insulator has a predefined width so that the characteristic impedance of said branch is substantially between 75Ω and 120Ω.

According to a particular embodiment, the second insulator is located close to an intersection of the first plane and the second plane.

According to a particular embodiment, the second insulator is positioned in a secant plane in the foreground and in the second plane.

According to a particular embodiment, the second insulator forms a rounded corner between the first plane and the second plane.

According to a particular embodiment, the first plane and the second plane are perpendicular.

According to a particular embodiment, the radio frequency device as previously described comprises a second set of antennas comprising the third antenna and a fourth antenna, and which is similar to the first set of antennas, as well as a third insulator similar to the first isolator and positioned between the third antenna and the fourth antenna.

According to a particular embodiment, the radio frequency device as previously described comprises a support comprising four faces comprising two first faces parallel to each other and two second faces parallel to each other, two first sets of antennas each positioned on a first distinct face and two second sets of antennas each positioned on a second separate face, the radiofrequency device further comprising two first insulators each positioned between the first antenna and the second antenna of a first set of separate antennas, two third insulators each positioned between a third antenna and a fourth antenna of a second separate set of antennas, as well as four second insulators each positioned in a separate corner of the support.

The invention also relates to a MIMO system comprising a radio frequency device as previously described as well as a radio frequency transmitter and a radio frequency receiver connected to the first sets of antennas and to the second sets of antennas of said radio frequency device.

The invention also relates to electronic equipment comprising a MIMO system as previously described.

According to a particular embodiment, the electronic equipment is a residential gateway.

Other characteristics and advantages of the invention will become apparent on reading the following description of particular non-limiting embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

• [Fig. 1] la figure 1 représente une vue de dessus d'un dispositif radiofréquence selon un mode de réalisation.
• [Fig. 2] la figure 2 représente une simulation du fonctionnement du dispositif radiofréquence illustré à la figure 1 lorsque la première antenne est en émission et que le premier isolateur n'est pas présent.
• [Fig. 3] la figure 3 représente une simulation du fonctionnement du dispositif radiofréquence illustré à la figure 1 lorsque la première antenne est en émission et que le premier isolateur est présent.
• [Fig. 4] la figure 4 représente une simulation du fonctionnement du dispositif radiofréquence illustré à la figure 1 lorsque la deuxième antenne est en émission et que le premier isolateur n'est pas présent.
• [Fig. 5] la figure 5 représente une simulation du fonctionnement du dispositif radiofréquence illustré à la figure 1 lorsque la deuxième antenne est en émission et que le premier isolateur est présent.
• [Fig. 6] la figure 6 représente le paramètre S₂₁ en fonction de la fréquence du dispositif radiofréquence illustré à la figure 1.
• [Fig. 7] la figure 7 représente les diagrammes de rayonnement de la première antenne du dispositif radiofréquence illustré à la figure 1.
• [Fig. 8] la figure 8 représente les diagrammes de rayonnement de la deuxième antenne du dispositif radiofréquence illustré à la figure 1.
• [Fig. 9] la figure 9 représente une vue en perspective d'une première variante du dispositif radiofréquence selon un mode de réalisation.
• [Fig. 10A] la figure 10A illustre une première position du deuxième isolateur du dispositif radiofréquence illustré à la figure 9.
• [Fig. 10B] la figure 10B illustre une deuxième position du deuxième isolateur du dispositif radiofréquence illustré à la figure 9.
• [Fig. 11] la figure 11 représente une simulation de champ électrique selon un premier plan du dispositif radiofréquence illustré à la figure 9 lorsque la première antenne est en émission et que le premier isolateur n'est pas présent.
• [Fig. 12] la figure 12 représente une simulation de champ électrique selon un premier plan du dispositif radiofréquence illustré à la figure 9 lorsque la première antenne est en émission et que le premier isolateur est présent.
• [Fig. 13] la figure 13 représente une simulation de champ électrique selon un deuxième plan du dispositif radiofréquence illustré à la figure 9 lorsque la première antenne est en émission et que le premier isolateur n'est pas présent.
• [Fig. 14] la figure 14 représente une simulation de champ électrique selon un deuxième plan du dispositif radiofréquence illustré à la figure 9 lorsque la première antenne est en émission et que le premier isolateur est présent.
• [Fig. 15] la figure 15 représente le paramètre S₂₁ en fonction de la fréquence du dispositif radiofréquence illustré à la figure 9.
• [Fig. 16] la figure 16 représente les diagrammes de rayonnement de la première antenne du dispositif radiofréquence illustré à la figure 9.
• [Fig. 17] la figure 17 représente les diagrammes de rayonnement de la troisième antenne du dispositif radiofréquence illustré à la figure 9.
• [Fig. 18] la figure 18 représente une vue en relief d'une troisième variante du dispositif radiofréquence selon un mode de réalisation.
• [Fig. 19] la figure 19 représente une simulation de champ électrique du dispositif radiofréquence illustré à la figure 18 lorsque la première antenne est en émission et que le dispositif d'isolation n'est pas présent.
• [Fig. 20] la figure 20 représente une simulation de champ électrique du dispositif radiofréquence illustré à la figure 18 lorsque la deuxième antenne est en émission et que le dispositif d'isolation n'est pas présent.
• [Fig. 21] la figure 21 représente une simulation de champ électrique du dispositif radiofréquence illustré à la figure 18 lorsque la première antenne est en émission et que le dispositif d'isolation est présent.
• [Fig. 22] la figure 22 représente une simulation de champ électrique du dispositif radiofréquence illustré à la figure 18 lorsque la deuxième antenne est en émission et que le dispositif d'isolation est présent.
• [Fig. 23] la figure 23 représente les diagrammes de rayonnement en gain combiné du premier groupe d'antennes du dispositif radiofréquence illustré à la figure 18.
• [Fig. 24] la figure 24 représente les diagrammes de rayonnement en gain combiné du deuxième groupe d'antennes du dispositif radiofréquence illustré à la figure 18.
• [Fig. 25] la figure 25 représente un diagramme de définition de bloc d'un équipement électronique intégrant un système MIMO comportant le dispositif radiofréquence illustré à la figure 18.
• [Fig. 26] la figure 26 représente une passerelle résidentielle intégrant le dispositif radiofréquence illustré à la figure 18.

The description of embodiments refers to the appended drawings, among which:

• [ Fig. 1 ] there figure 1 shows a top view of a radio frequency device according to one embodiment.
• [ Fig. 2 ] there figure 2 represents a simulation of the operation of the radio frequency device illustrated in figure 1 when the first antenna is transmitting and the first isolator is not present.
• [ Fig. 3 ] there picture 3 represents a simulation of the operation of the radio frequency device illustrated in figure 1 when the first antenna is transmitting and the first isolator is present.
• [ Fig. 4 ] there figure 4 represents a simulation of the operation of the radio frequency device illustrated in figure 1 when the second antenna is transmitting and the first isolator is not present.
• [ Fig. 5 ] there figure 5 represents a simulation of the operation of the radio frequency device illustrated in figure 1 when the second antenna is transmitting and the first isolator is present.
• [ Fig. 6 ] there figure 6 represents the parameter S ₂₁ as a function of the frequency of the radio frequency device illustrated in figure 1 .
• [ Fig. 7 ] there figure 7 represents the radiation patterns of the first antenna of the radiofrequency device illustrated in figure 1 .
• [ Fig. 8 ] there figure 8 represents the radiation patterns of the second antenna of the radiofrequency device illustrated in figure 1 .
• [ Fig. 9 ] there figure 9 shows a perspective view of a first variant of the radiofrequency device according to one embodiment.
• [ Fig. 10A ] there figure 10A illustrates a first position of the second isolator of the radiofrequency device shown in figure 9 .
• [ Fig. 10B ] there figure 10B illustrates a second position of the second isolator of the radiofrequency device shown in figure 9 .
• [ Fig. 11 ] there figure 11 represents an electric field simulation according to a first plane of the device radio frequency shown in figure 9 when the first antenna is transmitting and the first isolator is not present.
• [ Fig. 12 ] there figure 12 represents an electric field simulation according to a first plane of the radiofrequency device illustrated in figure 9 when the first antenna is transmitting and the first isolator is present.
• [ Fig. 13 ] there figure 13 represents an electric field simulation according to a second plane of the radiofrequency device illustrated in figure 9 when the first antenna is transmitting and the first isolator is not present.
• [ Fig. 14 ] there figure 14 represents an electric field simulation according to a second plane of the radiofrequency device illustrated in figure 9 when the first antenna is transmitting and the first isolator is present.
• [ Fig. 15 ] there figure 15 represents the parameter S ₂₁ as a function of the frequency of the radio frequency device illustrated in figure 9 .
• [ Fig. 16 ] there figure 16 represents the radiation patterns of the first antenna of the radiofrequency device illustrated in figure 9 .
• [ Fig. 17 ] there figure 17 represents the radiation patterns of the third antenna of the radiofrequency device illustrated in figure 9 .
• [ Fig. 18 ] there figure 18 shows a view in relief of a third variant of the radiofrequency device according to one embodiment.
• [ Fig. 19 ] there figure 19 shows an electric field simulation of the radio frequency device shown in face 18 when the first antenna is transmitting and the isolation device is not present.
• [ Fig. 20 ] there figure 20 shows an electric field simulation of the radio frequency device shown in figure 18 when the second antenna is transmitting and the isolation device is not present.
• [ Fig. 21 ] there figure 21 shows an electric field simulation of the radio frequency device shown in figure 18 when the first antenna is transmitting and the isolation device is present.
• [ Fig. 22 ] there figure 22 shows an electric field simulation of the radio frequency device shown in figure 18 when the second antenna is transmitting and the isolation device is present.
• [ Fig. 23 ] there figure 23 represents the combined gain radiation patterns of the first group of antennas of the radio frequency device shown in figure 18 .
• [ Fig. 24 ] there figure 24 represents the combined gain radiation patterns of the second group of antennas of the radio frequency device shown in figure 18 .
• [ Fig. 25 ] there figure 25 represents a block definition diagram of electronic equipment integrating a MIMO system comprising the radio frequency device illustrated in figure 18 .
• [ Fig. 26 ] there figure 26 represents a residential gateway integrating the radiofrequency device illustrated in figure 18 .

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figure 1 , there is described a radiofrequency device 1 according to one embodiment.

The radiofrequency device 1 comprises a first set of antennas 2 comprising a first antenna 2a and a second antenna 2b. The first antenna 2a and the second antenna 2b are flat in shape and both extend in a first plane 3. The first plane 3 is defined by an axis X and by an axis Z, the axis X and the axis Z being perpendicular.

The first antenna 2a and the second antenna 2b are here positioned on a support 4 made of a dielectric material and extending in the first plane 3. In this case, the support 4 is here made of a plastic material having a dielectric permittivity greater than 1 (for example, the dielectric permittivity of the plastic material used is approximately equal to 3).

The first antenna 2a operates in a first frequency band and the second antenna 2b operates in a second frequency band. It is understood here that an antenna operates in a frequency band (or at a frequency) means that said antenna is designed to transmit and/or receive, in an optimal manner, radio frequency signals in said frequency band (or respectively at said frequency).

Furthermore, the first frequency band and the second frequency band are here different but adjacent. Here, “adjacent” means that the first band of frequencies and the second band of frequencies are separated by a frequency difference between about 0 MHz and about 1 GHz. For example, if the first band of frequencies is greater than the second band of frequencies, said frequency deviation is the difference between the minimum frequency of the second band of frequencies and the maximum frequency of the first band of frequencies.

By way of example, the first antenna 2a could be a dual- band antenna operating at a frequency equal to 2.4 GHz and at a frequency equal to 5 GHz, and the second antenna 2b could be a simple mono-band antenna operating at a frequency of 6 GHz.

As another example, the first antenna 2a could be a mono-band antenna operating in a 5 GHz frequency band, ranging from 5170 MHz to 5835 MHz, and the second antenna 2 b could be a mono-band antenna operating in a band of 6GHz frequency, ranging from 5925MHz to 7125MHz.

The first antenna 2a and the second antenna 2b are here planar dipole antennas on supports of rectangular shapes. The first antenna 2a and the second antenna 2b both have an omnidirectional radiation pattern having the shape of a torus. The first antenna 2a generates a first maximum electric field on a first axis E _2a and the second antenna 2b generates a second maximum electric field on a second axis E _2b . The first axis E _2a is an axis of symmetry of the first antenna 2a parallel to the width thereof. The second axis E _2b is an axis of symmetry of the second antenna 2b parallel to the width thereof.

Here, the first axis E _2a and the second axis E _2b are parallel.

The radiofrequency device 1 further comprises a first insulator 5 of flat shape which extends in the first plane 3 between the first antenna 2a and the second antenna 2b. The first insulator 5 is here generally centered between the first antenna 2a and the second antenna 2b.

The first insulator 5 is positioned on the support 4 and fixed by fixing means comprising for example dowels, glue or even screws.

Still with reference to the figure 1 , the first insulator 5 comprises a first branch 6 and a second branch 7. The first branch 6 and the second branch 7 of the first insulator 5 are here formed by flat and rectilinear tracks made of a conductive material, for example aluminum, copper or even iron.

Furthermore, the second branch 7 of the first insulator 5 is here perpendicular to the first branch 6 of the first insulator 5 and extends from a central portion of said first branch 6. The first insulator 5 thus has a “T” shape. The “T” shape is simple and facilitates the manufacture of the first insulator 5 because it is a shape which can be cut with precision (in particular in a metal plate) and which is easily reproducible.

Thus, the first branch 6 of the first insulator 5 is a transmission line which is in open circuit between a first end 6a and a second end 6b. Moreover, the second branch 7 of the first insulator 5 is a stub which is in open circuit at a free end 7a. Thus, the second branch 7 and the first branch 6 of the first insulator 5 are electrically connected in parallel. The first insulator 5 is thus a passive element which performs the reciprocal bandstop resonator function. The first insulator 5 thus has a transmission coefficient which is the same regardless of the direction of flow of an electric current flowing through its first branch 6 and its second branch 7.

Furthermore, the first insulator 5 is not electrically connected. In particular, the first insulator 5 is not connected to an electrical ground plane. The first insulator 5 is thus electrically floating. It is noted in particular that this floating configuration of the first insulator 5 is particularly different from the solutions of the prior art. Indeed, according to art Previously, there are insulators mounted on PCBs (in English Printed Circuit Board), but the use of a PCB (which in particular has magnetic permeability) requires connecting said insulators to the electrical ground plane of said PCB.

The first axis E _2a and the second axis E _2b are both oriented here at an angle equal to 45 degrees with respect to the second branch 7 of the first insulator 5. The first axis E _2a extends directly in the vicinity of the first end 6a of first branch 6 of first insulator 5.

The dimensions of the first isolator 5 are predefined according to the space available, the environment in which it is used and a frequency band in which its influence must be maximum. It is indeed important to consider the environment in which the device 1 according to one embodiment is applied, and in particular the electrical parameters of the materials used (such as the dielectric permittivity) which impact the wavelengths, the resonance frequencies as well as as the characteristic impedances of the transmission lines (i.e. tracks).

Preferably, the first branch 6 of the first insulator 5 has a length approximately equal to at least a quarter of a first wavelength λ _A taking into account a medium in which the first insulator 5 extends.

, où εr est la permittivité diélectrique du matériau utilisé pour la fabrication du support diélectrique et où ν₁ est une première fréquence centrale qui est centrée entre une fréquence maximale et une fréquence minimale de la première bande de fréquences (dans laquelle opère la première antenne 2a), et où c est la célérité de l'onde électromagnétique. Par exemple, si la première bande de fréquences est une bande de fréquences allant de 5.1GHz à 5.9GHz, la première fréquence centrale ν₁ est environ égale à 5.5GHz.In a first example, the first isolator 5 is here designed to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b in the first frequency band and in the second frequency band but more significantly in the first. frequency band (in which operates the first antenna 2a). If the medium in which the first insulator 5 extends is air, the first wavelength λ _A is calculated with a dielectric permittivity equal to 1. On the other hand, if the medium in which the first insulator 5 extends is a dielectric support (for example a plastic support), the dielectric permittivity of said dielectric support is taken into account and the first wavelength λ _A is such that: $\frac{{\mathrm{\lambda }}_{\mathrm{AT}}}{4}=\frac{\mathrm{vs}}{4\times {\mathrm{<figure-callout\; id="1"\; label="\nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_1\times \sqrt{\mathit{\epsilon r}}}$

, where εr is the dielectric permittivity of the material used for manufacturing the dielectric support and where ν ₁ is a first central frequency which is centered between a maximum frequency and a minimum frequency of the first frequency band (in which the first antenna 2a operates ), and where c is the speed of the electromagnetic wave. For example, if the first frequency band is a frequency band ranging from 5.1 GHz to 5.9 GHz, the first central frequency ν ₁ is approximately equal to 5.5 GHz.

, où ν₁ est la première fréquence centrale de la première bande de fréquences (par exemple, 5,5GHz), et où ν₂ est une deuxième fréquence centrale qui est centrée entre une fréquence maximale et une fréquence minimale de la deuxième bande de fréquences (par exemple 6,5GHz). D'autres exemples de dimensionnement de la première branche 6 du premier isolateur 5 peuvent être obtenus selon l'isolation de la première bande de fréquences ou de la deuxième bande de fréquences recherchée.In another example, the first isolator 5 is here designed to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b in a balanced (or equal) manner between the first frequency band and the second frequency band. The first frequency band is for example a frequency band called the 5 GHz band and the second frequency band is for example a frequency band called the 6 GHz band. If the medium in which the first insulator 5 extends is different from air then the first wavelength λ _A is such that: $\frac{{\mathrm{\lambda }}_{\mathrm{AT}}}{4}=\frac{\mathrm{vs}}{4\times \frac{{\mathrm{<figure-callout\; id="1"\; label="\nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="\nu "\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_2}{2}\times \sqrt{\mathit{\epsilon r}}}$

, where ν ₁ is the first center frequency of the first frequency band (for example, 5.5 GHz), and where ν ₂ is a second center frequency which is centered between a maximum frequency and a frequency minimum of the second frequency band (for example 6.5 GHz). Other examples of dimensioning of the first branch 6 of the first insulator 5 can be obtained according to the isolation of the first frequency band or of the second frequency band sought.

The second branch 7 of the first insulator 5 has a length approximately equal to a quarter of the first wavelength λ _A retained. The first wavelength λ _A selected corresponds to a first selected frequency which is for example equal to 6.2 GHz when insulation at the start of the frequency band called the 6 GHz band (UNII-5) is sought. The first frequency selected can also be, for example, dependent on the first central frequency ν ₁ of the first frequency band (in which the first antenna 2a operates) and on the second central frequency ν ₂ of the second frequency band (in which the second antenna 2b). For example, the central frequency adopted is equal to (ν ₁ +ν ₂ )/2.

In one example, the dimensions of the first insulator 5, in particular the respective widths of the first branch 6 and of the second branch 7, are related to the characteristics of an antenna selected from among the first antenna 2a and the second antenna 2b. The respective dimensions of the first antenna 2a and of the second antenna 2b are considered in order to select the largest dimension(s). For example, when the first frequency band (in which the first antenna 2a operates) is the so-called 5GHz band frequency band and the second frequency band (in which the second antenna 2b operates) is the so-called 6GHz band frequency band , radiating strands or tracks of the first antenna 2a have larger dimensions or sizes than strands or radiating tracks of the second antenna 2b. The width of the radiating strands or tracks of the selected antenna makes it possible to determine the width of the first branch 6 and/or of the second branch 7 of the first insulator 5. If the first frequency band (first antenna 2a) is the band of frequencies called 5 GHz band and the second frequency band (second antenna 2b) is the frequency band called 6 GHz band, the respective widths of the first branch 6 and the second branch 7 of the first isolator 5 can be of the order of 2.5 mm-3mm.

The first antenna 2a is selected to determine the dimensions of the first insulator 5 and the first antenna 2a is positioned on a PCB, itself resting on a first dielectric support (made for example with a plastic material), the assembly (the PCB and the first dielectric support) having a dielectric permittivity approximately equal to 4.3. The first insulator 5 is for its part, in one example, positioned on a second dielectric support (made for example with a plastic material) which can be identical to or different from the first dielectric support on which the first antenna 2a is positioned, and having a permittivity dielectric approximately equal to 3. Due to the proximity of two different dielectric permittivities, and knowing that the first antenna 2a is selected to size the first insulator 5, the respective characteristic impedances of the first branch 6 and of the second branch 7 of the first insulator 5 are approximately equal to the characteristic impedance of the first antenna 2a.

In various examples, the first branch 6 and the second branch 7 of the first insulator 5 respectively have a width which ensures that the characteristic impedances respectively of said first branch 6 and of said second branch 7 are included in the interval [75Ω, 120Ω]. This makes it possible to maximize an electric current flowing through said first branch 6 and said second branch 7 and thus to maximize the attenuation of the coupling by electromagnetic radiation.

Furthermore, the first isolator 5 operates in the near field. Still considering that the first isolator 5 is arranged to more significantly attenuate the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b in the first frequency band, a distance between the first end 6a of the first branch 6 of the first insulator 5 and the first axis E _2a is between 5 millimeters and 1 centimeter. This distance makes it possible to optimally limit the intensity of the electric field generated by the first antenna 2a and picked up by the second antenna 2b. In another example, this distance is greater than 1 centimeter, for example 1.5 centimeters.

THE figure 2 , 3, 4 and 5 highlight the role of the first isolator 5 in the radiofrequency device 1. The first antenna 2a is here a Wi-Fi antenna operating in a frequency band ranging from 5.1 GHz to 5.9 GHz. The second antenna 2b is here a Wi-Fi antenna operating in a frequency band ranging from 5.9 GHz to 7.2 GHz. The first frequency band of the first antenna 2a and the second frequency band of the second antenna 2b are thus adjacent.

On each of figure 2 , 3, 4 and 5 , curved field lines represent the orientation of the electric field in the first plane 3. In addition, the intensity of said electric field (in Vm ^-1 ) is represented here in gray level.

With reference to figure 2 And 3 , the first antenna 2a operates here in transmission, that is to say it transmits radiofrequency signals in its frequency band. Field lines 8 therefore represent here the orientation of the electric field generated by the first antenna 2a. On the contrary, the second antenna 2b is inactive here, that is to say that it neither emits nor receives any radiofrequency signal in its frequency band.

When the radiofrequency device 1 does not include the first isolator 5 ( figure 2 ), the electric field generated by the first antenna 2a propagates without obstacle through the support 4 to the second antenna 2b. The second antenna 2b thus picks up a large part of the electric field generated by the first antenna 2a. The field lines 8 are thus concentrated on and in the vicinity of the second antenna 2b. Thus, knowing that the first antenna 2a and the second antenna 2b respectively operate in frequency bands which are adjacent, the coupling by electromagnetic radiation between said first antenna 2a and said second antenna 2b is important.

When the radiofrequency device 1 includes the first isolator 5 ( picture 3 ), the electric field generated by the first antenna 2a is filtered, that is to say attenuated thanks to the reciprocal band-stop resonator function of said first insulator 5. The field lines 8 are thus concentrated on and in the vicinity of the first isolator 5 (and not in the vicinity of the second antenna 2b). More precisely, the electric field generated by the first antenna 2a is concentrated at the level of the first end 6a of the first branch 6 of the first insulator 5 and at the level of the free end 7a of the second branch 7 of the first insulator 5. The coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b is thus significantly reduced. Furthermore, the first insulator 5 modifies the near-field orientation of the electric field generated by the first antenna 2a.

With reference to figures 4 and 5 , the first antenna 2a is here inactive and the second antenna 2b operates in transmission. Field lines 9 therefore represent here the orientation of the electric field generated by the second antenna 2b.

When the radiofrequency device 1 does not include the first isolator 5 ( figure 4 ), the electric field generated by the second antenna 2b propagates without obstacle through the support 4 to the first antenna 2a. The field lines 9 are therefore concentrated on and in the vicinity of the first antenna 2a. Thus, the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b is important.

When the radiofrequency device 1 includes the first isolator 5 ( figure 5 ), the field lines 9 are concentrated at the level of the first end 6a and of the second end 6b of the first branch 6 of the first insulator 5 and at the level of the free end 7a of the second branch 7 of the first insulator 5. Thus, the number of field lines 9 in the vicinity of the first antenna 2a is greatly reduced. The coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b is therefore significantly reduced.

It should be noted that the first isolator 5 has better performance when it is the first antenna 2a which is transmitting (compared to the case where it is the second antenna 2b which is transmitting). This result is logical because the first isolator 5 is here sized to operate in the vicinity of a maximum frequency of the first frequency band (ranging from 5.1 GHz to 5.9 GHz).

There figure 6 represents the amplitude in decibels of a parameter (in English Scattering Parameter ) S ₂₁ as a function of the frequency. The parameter S ₂₁ corresponds to the transmission coefficient between the second antenna 2b and the first antenna 2a. Curve 10 is the curve of parameter S ₂₁ when the first insulator 5 is not present and curve 11 is the curve of parameter S ₂₁ when the first insulator 5 is present. The first isolator 5 is here sized to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b in a frequency band ranging from 5 GHz to 7 GHz. It is clear that the first isolator 5 reduces the amplitude of the parameter S ₂₁ in the frequency band for which it is dimensioned. Indeed, a minimum reduction equal to about 5dB in the amplitude of parameter S ₂₁ is observed in the vicinity of a frequency equal to 5.5GHz (reference mark R1 on the figure 6 ) and maximum reduction of approximately 34dB in the vicinity of a frequency equal to 6.3GHz (mark R2 on the figure 6 ). The first isolator 5 therefore makes it possible to effectively reduce the coupling by electromagnetic radiation between the first antenna 2a and the second antenna 2b in the frequency band for which it is dimensioned.

With reference to figures 7 and 8 , a Y axis is introduced here, perpendicular to the X axis and to the Z axis so that the three axes X, Y, Z form an orthogonal Cartesian coordinate system (space of dimension 3) defining three cuts, a first XZ cut (i.e. a cut according to the first plane 3), a second YZ cut and a third XY cut.

There figure 7 represents a radiation pattern 12 of the first antenna 2a along the first XZ section, a radiation pattern 13 of the first antenna 2a along the second YZ section and a radiation pattern 14 of the first antenna 2a along the third XY section. The radiation patterns 12, 13, 14 correspond to the scenario of the figure 2 And 3 , that is to say that the first antenna 2a is transmitting (in the first frequency band ranging from 5.1 GHz to 5.9 GHz) and the second antenna 2 b is inactive. It is common in the radiofrequency domain to characterize an antenna using its radiation pattern which represents the angular distribution (in degrees) of the gain of said antenna (in isotropic decibels).

On the radiation diagrams 12, 13, 14, the solid line curve corresponds to the far field directivity of the first antenna 2a when the first insulator 5 is not present and the dotted line curve corresponds to the field directivity distant from the first antenna 2a when the first insulator 5 is present.

The radiation patterns 12, 13, 14 show that the first insulator 5 modifies the directivity in the far field of the first antenna 2a.

In particular, the radiation pattern 12 according to the first section XZ shows that the directivity in the far field of the first antenna 2a is more homogeneous when the first insulator 5 is present (curve 12b). By homogeneous, it is understood that the gain of the first antenna 2a is approximately constant as a function of the propagation angle of the radiation emitted by said first antenna 2a. More precisely, when the first insulator 5 is not present (curve 12a), the maximum relative variation in gain of the first antenna 2a is of the order of 8 dBi, whereas when the first isolator 5 is present (curve 12b), the maximum relative variation in gain of the first antenna 2a is the order of 3dBi.

The radiation pattern 13 according to the second section YZ does not reveal a significant shift in the directivity in the far field of the first antenna 2a.

The radiation pattern 14 according to the third XY section shows that the maximum gain of the first antenna is shifted when the first insulator 5 is present. Indeed, when the first isolator 5 is not present (curve 14a), the gain of the first antenna 2a is maximum in the vicinity of an angle of 270 degrees whereas when the first isolator 5 is present (curve 14b), the gain of the first antenna 2a is maximum in the vicinity of an angle of 180 degrees.

There figure 8 shows a radiation pattern 15 of the second antenna 2b along the first XZ section, a radiation pattern 16 of the second antenna 2b along the second YZ section and a radiation pattern 17 of the second antenna 2b along the third XY section. The radiation patterns 15, 16, 17 correspond to the scenario of the figures 4 and 5 , that is to say that the first antenna 2a is inactive and the second antenna 2b is transmitting (in the second frequency band ranging from 5.9 GHz to 7.2 GHz).

On the radiation diagrams 15, 16, 17, the solid line curve corresponds to the directivity in the far field of the second antenna 2b when the first insulator 5 is not present and the dotted line curve corresponds to the far-field directivity of the second antenna 2b when the first insulator 5 is present.

The radiation patterns 15, 16, 17 demonstrate that the first insulator 5 has a moderate influence on the directivity in the far field of the second antenna 2b. Indeed, the profile of the directivity in the far field of the second antenna 2b when the first insulator 5 is not present is generally similar to the profile of the directivity in the far field of the second antenna 2b when the first insulator 5 is present. This is due to the fact that the second axis E _2b of the second maximum electric field of the second antenna 2b does not extend directly in the vicinity of the first insulator 5.

It should be noted that the dimensions of the first isolator 5 can be adjusted according to a target frequency band.

It should be noted that the greater the conductivity of the material used to manufacture the first insulator 5, the higher the insulation performance of said first insulator 5.

In addition, the first axis E _2a of the first maximum electric field (of the first antenna 2a) and the second axis E _2b of the second maximum electric field (of the second antenna 2b) could be perpendicular to the second branch 7 of the first insulator 5 .

With reference to the figure 9 , the radiofrequency device 1 according to one embodiment further comprises at least one second isolator 18. The radiofrequency device 1 may further comprise a single second isolator 18.

The second isolator 18 is positioned on one side of a particular antenna among the first antenna 2a or the second antenna 2b, said side of the particular antenna being opposed to the first insulator. On the figure 9 , the particular antenna is the first antenna 2a (which this time is positioned to the left of the antenna 2b, not represented on the figure 9 ). The second insulator 18 is used to modify and reorient the directivity in the far field of the first antenna 2a caused by the presence of the first insulator 5. The second insulator 18 is considered as a parasitic element influencing the cartography of the electric field on the support 54 .

The first antenna 2a is here positioned on a support 54 comprising a first face extending along the first plane 3 and a second face extending along a second plane 21. The second plane 21 is defined by the Y axis and the axis Z. The second plane is therefore oriented by an angle Ω equal to 90 degrees with respect to the first plane 3. It should be noted that the angle Ω of inclination between the first plane 3 and the second plane 21 could be different 90 degrees

The second insulator 18 is here positioned in a corner of the support 54 defined by an intersection of the first plane 3 and the second plane 21 via fixing means comprising for example riveting pins, glue or even screws.

The second insulator 18 here comprises a single branch 19. The branch 19 of the second insulator 18 is here formed by a flat and rectilinear track made of a conductive material, for example aluminum, copper or even iron. The second insulator 18 thus has an “I” or slender shape. The "I" shape is simple and facilitates the manufacture of the second insulator 18 because it is a shape which can be cut with precision (in particular in a metal plate) and which is easily reproducible.

Thus, branch 19 of second insulator 18 is a transmission line which is in open circuit between one end 19a and one end 19b. The second insulator is thus a passive element.

Further, the second insulator 18 is not electrically connected. In particular, the second insulator 18 is not connected to an electrical ground plane. The second insulator 18 is thus electrically floating.

Still with reference to the figure 9 , it may be provided that the radiofrequency device 1 further comprises a third antenna 20b. The third antenna 20b is flat in shape and here extends into the second plane 21.

The third antenna 20b operates in a third frequency band. The third frequency band could be different from the first frequency band and the second frequency band but could also be similar to the first frequency band or the second frequency band.

By way of example, the third antenna 20b could be a single-band antenna operating in the so-called 6 GHz band frequency band.

The third antenna 20b is here a planar dipole antenna of rectangular shape. Thus, the third antenna 20b has an omnidirectional radiation pattern having the shape of a torus. The third antenna 20b generates a third maximum electric field on a third axis E _20b . The position of the third antenna 20b in the second plane 21 is thus defined along the third axis E _20b .

With reference to the figure 9 , the second insulator 18 is here positioned in a corner of the support 54 between a antenna which is the first antenna 2a and the third antenna 20b.

With reference to the figure 10A , the second insulator 18 can be positioned in a secant plane 22 to the first plane 3 and to the second plane 21. The second insulator 18 is thus positioned at least partially on a chamfer of the support 54.

With reference to the figure 10B , the second insulator 18 can also form a rounded corner 23 between the first plane 3 and the second plane 21. The second insulator 18 is thus positioned at least partially on a fillet of the support 54.

When it is placed between the first antenna 2a and the third antenna 20b, the second insulator 18 makes it possible to reduce coupling by electromagnetic radiation between said first antenna 2a and said third antenna 20b.

The dimensions of the second isolator 18 are predefined according to the space available, the environment in which it is used and a frequency band in which its influence must be maximum.

The dimensions of the second insulator 18 are indicated here in the case where the second insulator 18 is arranged to insulate the third antenna 20b from the electric field generated by the first antenna 2a.

Preferably, the branch 19 of the second insulator 18 has a length approximately equal to half of a second wavelength λ _B taking into account a medium in which the second insulator 18 extends.

, où εr est la permittivité diélectrique du matériau utilisé pour la fabrication du support diélectrique, où c est la célérité de l'onde électromagnétique, et où ν₁ est la première fréquence centrale de la première bande de fréquences dans laquelle opère la première antenne 2a.In a first example, the second isolator 18 is here designed to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the third antenna 20b in the first frequency band (in which the first antenna 2a operates) and in the third frequency band (in which the third antenna 20b operates) but more significantly in the first frequency band. If the medium in which the second insulator 18 extends is air, the second wavelength λ _B is calculated with a dielectric permittivity equal to 1. On the other hand, if the medium in which the second insulator 18 extends is a dielectric support (for example a plastic support), the dielectric permittivity of said dielectric support is taken into account and the second wavelength λ _B is such that: $\frac{{\mathrm{<figure-callout\; id="2"\; label="\lambda \; B"\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_{\mathrm{B}}}{2}=\frac{\mathrm{<figure-callout\; id="2"\; label="vs"\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">vs</figure-callout>}}{2\times {\mathrm{<figure-callout\; id="1"\; label="\nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_1\times \sqrt{\mathit{\epsilon r}}}$

, where εr is the dielectric permittivity of the material used for manufacturing the dielectric support, where c is the celerity of the electromagnetic wave, and where ν ₁ is the first central frequency of the first frequency band in which the first antenna 2a operates .

, où ν₁ est la première fréquence centrale de la première bande de fréquences (par exemple, 5,5GHz), et ν₃ est une troisième fréquence centrale qui centrée entre une fréquence maximale et une fréquence minimale de la troisième bande de fréquences (par exemple 6,5GHz). D'autres exemples de dimensionnement de la branche 19 du deuxième isolateur 18 peuvent être obtenus selon l'isolation de la première bande de fréquences ou de la troisième bande de fréquences recherchée.In another example, the second isolator 18 is here designed to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the third antenna 20b in a balanced (or equal) manner between the first band of frequencies and the third band of frequencies. The first frequency band is for example the so-called 5 GHz frequency band and the third frequency band is for example the so-called 6 GHz frequency band. If the medium in which the second insulator 18 extends is different from air then the second wavelength λ _B is such that: $\frac{{\mathrm{<figure-callout\; id="2"\; label="\lambda \; B"\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_{\mathrm{B}}}{2}=\frac{\mathrm{<figure-callout\; id="2"\; label="vs"\; filenames="imgf0008.png,imgf0009.png"\; state="\{\{state\}\}">vs</figure-callout>}}{2\times \frac{{\mathrm{<figure-callout\; id="1"\; label="\nu "\; filenames="imgf0001.png,imgf0004.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_1+{\mathrm{<figure-callout\; id="3"\; label="\nu "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\nu </figure-callout>}}_3}{2}\times \sqrt{\mathit{\epsilon r}}}$

, where ν ₁ is the first center frequency of the first frequency band (for example, 5.5 GHz), and ν ₃ is a third center frequency which is centered between a maximum frequency and a minimum frequency of the third frequency band (for example example 6.5GHz). Other examples of dimensioning of branch 19 of second isolator 18 can be obtained depending on the isolation of the first frequency band or the third frequency band sought.

In one example, the dimensions of the second insulator 18, in particular the width of the branch 19 is related to the characteristics of an antenna selected from among the first antenna 2a and the third antenna 20b. The respective dimensions of the first antenna 2a and of the third antenna 20b are considered in order to select the largest dimension(s). For example, when the first frequency band (in which the first antenna 2a operates) is the frequency band known as the 5 GHz band and the third frequency band (in which the third antenna 20b operates) is the frequency band known as the 6 GHz band , the radiating strands or tracks of the first antenna 2a have larger dimensions or sizes than the radiating strands or tracks of the third antenna 20b. The width of the radiating strands or tracks of the selected antenna (between the first antenna 2a and the third antenna 20b) makes it possible to determine the width of the formwork 19 of the second insulator 18. If the first frequency band (first antenna 2a) is the frequency band called 5 GHz band and the third frequency band (third antenna 20b) is the frequency band called 6 GHz band, the width of the branch 19 of the second insulator 18 can be of the order of 2.5 mm-3 mm.

The first antenna 2a is selected to determine the dimensions of the second insulator 18 and the first antenna 2a is positioned on a PCB, itself resting on a first dielectric support (made for example with a plastic material), the assembly (the PCB and the first dielectric support) having a dielectric permittivity approximately equal to 4.3. The second insulator 18 is for its part, in one example, positioned on a second dielectric support (made for example with a plastic material) which can be identical to or different from the first support on which the first antenna 2a is positioned, and having a dielectric permittivity approximately equal to 3. Due to the proximity of two different dielectric permittivities, and knowing that the first antenna 2a is selected to size the second insulator 18, the characteristic impedance of the branch 19 of the second insulator 18 is approximately equal to the impedance characteristic of the first antenna 2a.

In various examples, the branch 19 of the second insulator 18 has a width which ensures that the characteristic impedance of said branch 19 is included in the interval [75Ω, 120Ω]. This makes it possible to maximize an electric current flowing through said branch 19 and thus to maximize the attenuation of the coupling by electromagnetic radiation.

In another example, the width of the branch 19 of the second insulator 18 is at least equal to the width of the first branch 6 and/or of the second branch 7 of the first insulator 5. In yet another example, the width of the branch 19 of the second insulator 18 is approximately equal to twice the width of the first branch 6 and/or of the second branch 7 of the first insulator 5.

Furthermore, the second isolator 18 operates in the near field. Still considering that the second insulator 18 is here arranged to insulate the third antenna 20b from the electric field generated by the first antenna 2a, a distance between the second insulator 18 and the first axis E _2a is between 5 millimeters and 1 centimeter. This distance makes it possible to optimally limit the intensity of the electric field generated by the first antenna 2a and picked up by the third antenna 20b. In another example, this distance is greater than 1 centimeter, for example 1.5 centimeters.

THE figure 11 , 12 , 13 And 14 highlight the role of the second isolator 18 in the radiofrequency device 1. The first antenna 2a is here a Wi-Fi antenna operating in a frequency band ranging from 5.1 GHz to 5.9 GHz, that is to say in the band of frequencies known as the 5 GHz band. The third antenna 20b is here a Wi-Fi antenna operating in a frequency band ranging from 5.9 GHz to 7.2 GHz, that is to say in the frequency band known as the 6 GHz band. The first frequency band of the first antenna 2a and the third frequency band of the third antenna 20b are thus adjacent.

On each of figure 11 , 12 , 13 And 14 , curved field lines 24 represent the orientation of the electric field in the first plane 3 and in the second plane 21. In addition, the intensity of said electric field (in Vm ⁻¹ ) is represented here in gray level. The first antenna 2a operates here in transmission and the third antenna 20b is inactive here.

THE figure 11 And 12 represent the orientation and intensity of the electric field generated by the first antenna 2a in the first plane 3.

THE figure 13 And 14 represent the orientation and intensity of the electric field generated by the first antenna 2a in the second plane 21.

When the radiofrequency device 1 does not include the second insulator 18, the electric field generated by the first antenna 2a propagates through the support 54 according to the first axis E _2a ( figure 11 ). In addition, the field lines 24 are concentrated at the level of the third antenna 20b which shows that said third antenna 20b picks up a significant part of the electric field generated by the first antenna 2a ( figure 13 ).

When the radiofrequency device 1 includes the second isolator 18 ( figure 12 And figure 14 ), the electric field generated by the first antenna 2a does not propagate along the first axis E _2a . The field lines 24 are thus concentrated at the level of the end 19a and the end 19b of the branch 19 of the second insulator 18. In other words, the field lines 24 are deflected from their initial orientation (i.e. say of their orientation when the second insulator 18 is not present). The deviation of the field lines 24 also makes it possible to attenuate the part of the electric field generated by the first antenna 2a picked up by the third antenna 20b. The second insulator 18 thus makes it possible to reduce the coupling by electromagnetic radiation between the first antenna 2a and the third antenna 20b.

There figure 15 represents the amplitude in decibels of parameter S ₂₁ as a function of frequency. The parameter S ₂₁ corresponds to the transmission coefficient between the third antenna 20b and the first antenna 2a. A curve 25 is the curve of the S parameter ₂₁ when the second isolator 18 is not present and a curve 26 is the curve of the S parameter ₂₁ when the second isolator 18 is present. The second isolator 18 is here sized to attenuate the coupling by electromagnetic radiation between the first antenna 2a and the third antenna 20b in a frequency band ranging from 5 GHz to 7 GHz. The second isolator 18 slightly reduces the amplitude of the parameter S ₂₁ in the band of frequencies for which it is dimensioned. Indeed, a maximum reduction of approximately 8dB is observed in the vicinity of a frequency equal to 5.2GHz (mark R3 on the figure 15 ). The second isolator 18 therefore makes it possible to slightly reduce the coupling by electromagnetic radiation between the first antenna 2a and the third antenna 20b in the frequency band for which it is dimensioned.

There figure 16 shows a radiation pattern 27 of the first antenna 2a along the first XZ section, a radiation pattern 28 of the first antenna 2a along the second YZ section and a radiation pattern 29 of the first antenna 2a along the third XY section. The radiation patterns 27, 28, 29 correspond to the scenario of the figure 11 , 12 , 13 , 14 that is to say that the first antenna 2a is transmitting (in the first frequency band ranging from 5.1 GHz to 5.9 GHz) and the third antenna 20b is inactive.

On the radiation patterns 27, 28, 29, the solid line curve corresponds to the far field directivity of the first antenna 2a when the second insulator 18 is not present and the dotted line curve corresponds to the field directivity distant from the first antenna 2a when the second insulator 18 is present.

The radiation patterns 27, 28, 29 show that the second insulator 18 modifies the directivity in the far field of the first antenna 2a.

In particular, the radiation pattern 27 according to the first section XZ shows that the directivity in the far field of the first antenna 2a is globally more homogeneous when the second insulator 18 is present (curve 27b). More precisely, when the second isolator 18 is not present (curve 27a), the maximum relative gain variation of the first antenna 2a is of the order of 7dBi whereas when the second isolator 18 is present (curve 27b), the maximum relative gain variation of the first antenna 2a is of the order of 5dBi.

The radiation pattern 28 according to the third XY section shows that the maximum of the gain of the first antenna 2a is shifted when the second insulator 18 is present. Indeed, when the second isolator 18 is not present (curve 28a), the gain of the first antenna 2a is maximum for an angle interval ranging from 210 degrees to 300 degrees whereas when the second isolator 18 is present ( curve 28b), the gain of the first antenna 2a is maximum in the vicinity of a first angle equal to 0 degrees and in the vicinity of a second angle equal to 180 degrees.

There figure 17 shows a radiation pattern 30 of the third antenna 20b along the first XZ section, a radiation pattern 31 of the third antenna 20b along the second YZ section and a radiation pattern 32 of the third antenna 20b along the third XY section. The radiation patterns 30, 31, 32 correspond to the case in which the third antenna 20b is transmitting (in the third frequency band ranging from 5.9 GHz to 7.2 GHz).

On the radiation patterns 30, 31, 32, the solid line curve corresponds to the far field directivity of the third antenna 20b when the second insulator 18 is not present and the dotted line curve corresponds to the field directivity away from the third antenna 20b when the second insulator 18 is present.

The radiation patterns 30, 31, 32 show that the second insulator 18 has an almost negligible influence on the directivity in the far field of the third antenna 20b. Indeed, the profiles of the far-field directivity as well as the gain values of the third antenna 20b when the second isolator 18 is not present and when the second isolator 18 and present are globally similar. This is due to the fact that the third axis E _20b of the third maximum electric field of the third antenna 20b does not extend directly in the vicinity of the second insulator 18.

It should be noted that the attenuation produced by the second insulator 18 is generally lower than that produced by the first insulator 5. This is explained by the fact that the second insulator 18 can be seen as a parasitic wave director element .

It should be noted that the dimensions of the first isolator 5 and/or of the second isolator 18 can be adjusted according to a target frequency band.

It should be noted that the greater the conductivity of the material used to manufacture the second insulator 18, the higher the insulation performance of said second insulator 18.

With reference to the figure 18 , the radiofrequency device 1 further comprises a second set of antennas 20 comprising the third antenna 20b and a fourth antenna 20a. The second set of antennas 20 is here similar to the first set of antennas 2. Thus, the third antenna 20b is similar to the second antenna 2b and the fourth antenna 20a is similar to the first antenna 2a.

The third antenna 20b and the fourth antenna 20a extend in the second plane 21 and are positioned on the support 54.

A third isolator 33 similar to the first isolator 5 is positioned between the third antenna 20b and the fourth antenna 20a. The third insulator 33 is thus arranged to reduce coupling by electromagnetic radiation between the third antenna 20b and the fourth antenna 20a.

With reference to the figure 18 , it is also provided that the radiofrequency device 1 comprises two first sets of antennas 2, two second sets of antennas 20, two first isolators 5, two third isolators 33 and four second isolators 18.

The radiofrequency device 1 here rests on a cylindrical support 40 of square section (with slightly rounded corners). The cylindrical support 40 has two first faces 40a, the two first faces 40a being parallel to each other; and two second faces 40b, the two second faces 40b being parallel to each other. Cylindrical support 40 thus has four corners 41, 42, 43, 44. Cylindrical support 40 thus has the overall shape of a rectangular crown.

Preferably, the cylindrical support 40 is made from a material having a dielectric permittivity greater than 1. For example, the cylindrical support 40 is made from a plastic material or from a polymer material.

A first set of antennas 2 is positioned on each of the first two faces 40a of the cylindrical support 40. A first insulator 5 is positioned between the first antenna 2a and the second antenna 2b of each of the first two sets of antennas 2.

A second set of antennas 20 is positioned on each of the two second faces 40b of the cylindrical support 40. A third insulator 33 is positioned between the third antenna 20b and the fourth antenna 20a of each of the two second sets of antennas 20.

A second insulator 18 is positioned on each of the four corners, 41, 42, 43, 44 of the cylindrical support 40.

A first group of antennas G1 and a second group of antennas G2 are defined.

The first group of antennas G1 comprises the first antenna 2a of each of the first two sets of antennas 2 and the fourth antenna 20a of each of the two second sets of antennas 20. The first group of antennas G1 thus comprises four antennas. The antennas of group G1 are here dual-band Wi-Fi antennas operating in a frequency band called the 2.4GHz band and in the frequency band called the 5GHz band. In another example, the antennas of group G1 are antennas according to 802.11 technology and are single-band and operate in the so-called 5 GHz band frequency band. In another example, the antennas of group G1 are antennas according to 802.11 technology and are single-band and operate in the frequency band known as the 6 GHz band. In yet another example, the antennas of group G1 are tri-band antennas comprising different subsets of electrical conductors allowing said antennas of group G1 to operate both in the frequency band known as the 2.4 GHz band, in the band of frequencies called 5GHz band and in the frequency band called 6GHz band.

The second group of antennas G2 comprises the second antenna 2b of each of the two first sets of antennas 2 and the third antenna 20b of each of the two second sets of antennas 20. The second group of antennas G2 thus comprises four antennas. Group G2 antennas Here are mono-band Wi-Fi antennas operating in the frequency band known as the 6GHz band.

Furthermore, in the rest of the description, the first two insulators 5, the two third insulators 33 and the four second insulators 18 will be referred to as an isolation device.

THE figures 19, 20 , 21, 22 highlight the role of the first isolator 5, the second isolator 18 and the third isolator 33 in the radio frequency device 1. The first antenna 2a which belongs to the first group of antenna G1 is here in transmission.

On the figures 19, 20 , 21, 22 , the intensity of the electric field (in Vm ^-1 ) is represented here according to three distinct zones. A first zone Z1 from 0 Vm ^-1 to 1000 Vm ^-1 , a second zone Z2 from 1000 Vm ^-1 to 1400 Vm ^-1 and a third zone Z3 from 1400 Vm ^-1 to about 2360 V.m ^-1 .

On the figure 19 And 21 , the first antenna 2a (belonging to the first group of antennas G1) is transmitting and the other antennas are inactive.

When the isolation device is not present ( figure 19 ), part of the electric field generated by the first antenna 2a is picked up by the other antennas, and in particular by the second antenna 2b.

When the isolation device is present ( figure 21 ), the electric field generated by the first antenna 2a is picked up by the isolation device, here in particular by the first insulator 5. The coupling by electromagnetic radiation between the antennas of the radiofrequency device 1 is thus greatly reduced.

On the figure 20 And 22 , the second antenna 2b (belonging to the second group of antennas G2) is transmitting and the other antennas are inactive.

When the isolation device is not present ( figure 20 ), part of the electric field generated by the second antenna 2b is picked up by the other antennas, and in particular by the first antenna 2b and the fourth antenna 20a ( figure 22 ).

When the isolation device is present ( figure 22 ), the electric field generated by the second antenna 2b is picked up by the isolation device, here in particular by the second insulator 18. The coupling by electromagnetic radiation between the antennas of the radio frequency device 1 is thus greatly reduced.

There figure 23 represents a radiation pattern 46 along the first XZ section, a radiation pattern 47 along the second YZ section and a radiation pattern 48 along the third XY section of the antennas of the first group of antennas G1. More precisely, the radiation patterns 46, 47, 48 are here average combined gain radiation patterns.

On the radiation patterns 46, 47, 48, the solid line curve corresponds to the combined far-field directivity of the antennas of the first group of antennas G1 when the isolation device is not present and the dotted line curve corresponds to the combined far-field directivity of the antennas of the first group of antennas G1 when the isolation device is present.

The radiation patterns 46, 47, 48 demonstrate that the isolation device makes it possible to substantially homogenize the directivity in the far field of the antennas of the first group of antennas G1.

There figure 24 represents a radiation pattern 49 along the first XZ section, a radiation pattern 50 along the second YZ section and a radiation pattern 51 according to the third section XY of the antennas of the second group of antennas G2. More precisely, the radiation patterns 49, 50, 51 are here average combined gain radiation patterns.

On the radiation patterns 49, 50, 51, the solid line curve corresponds to the combined far-field directivity of the antennas of the second group of antennas G2 when the isolation device is not present and the dotted line curve corresponds to the combined far-field directivity of the antennas of the second group of antennas G2 when the isolation device is present.

The radiation patterns 49, 50, 51 demonstrate that the isolation device has a limited influence on the directivity in the far field of the antennas of the second group of antennas G2.

The isolation device thus has a greater influence on a frequency band in which the antennas of the first group of antennas G1 operate than on a frequency band in which the antennas of the second group of antennas G2 operate.

The radio frequency device 1 according to one embodiment therefore makes it possible to respond to the isolation constraints between antennas when adjacent frequency bands are used while guaranteeing that the radiation pattern of said antennas is omnidirectional (that is to say that the angular distribution of the gain of said antennas is homogeneous).

Furthermore, the radio frequency device does not require a particular antenna technology (for example, ceramic antennas) and can be implemented using antennas having conventional dimensions.

With reference to the figure 25 , the radiofrequency device 1 according to one embodiment is here integrated into a MIMO system 101 (in English Multiple-Input Multiple-Output ) which itself is integrated into an electronic equipment 100. The MIMO system 101 comprises a radiofrequency transmitter 102 and a radio frequency receiver 103 which are both connected to the radio frequency device 1 according to different embodiments, such as for example the radio frequency device 1 comprising the first sets of antennas 2 and the second sets of antennas 20. The radio frequency transmitter 102 is arranged to transmit electrical signals to the radiofrequency device 1. The radiofrequency receiver 103 is arranged to receive electrical signals from radiofrequency signals received by the radiofrequency device 1.

With reference to the figure 26 , the radiofrequency device 1 is integrated in particular into an electronic equipment 100 which is a residential gateway. The residential walkway here has a tower shape.

Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

The radiofrequency device according to embodiments applies beneficially to any electronic equipment requiring the combination of multiple radiofrequency interfaces (in particular communication technologies using different but adjacent frequency bands) and/or requiring a plurality of transmission paths on the same frequency band, all in a small space.

It should be noted that the first insulator 5 here has a “T” shape but that it is entirely possible for the first insulator 5 to have another shape. For example, the first insulator 5 could comprise three branches, all three of which are electrically conductive, arranged so that said first insulator 5 has a "Y" shape. More broadly, the shape of the first insulator 5 can be adapted according, for example, to the specified performance of the radio frequency device 1. The same is true for the third insulator 33 which is similar to the first insulator 5.

Similarly, the second insulator 18 here has an "I" shape but it is quite possible that the second insulator 18 has another shape. It should be noted that the shape of the second isolator 18 can be adapted according, for example, to the specified performance of the radio frequency device 1.

It should be noted that the first insulator 5 is not necessarily fixed on the same support as that on which the first antenna 2a and the second antenna 2b are fixed. For example, the first insulator 5 could be fixed on a first auxiliary support, different from the support 4 or from the support 54 and thus be maintained “in the air” between the first antenna 2a and the second antenna 2b. It is the same for the third insulator 33 which is similar to the first insulator 5. The third insulator 33 is therefore not necessarily fixed on the same support as that on which the third antenna 20b and the fourth antenna 20a are fixed.

Similarly, the second insulator 18 is not necessarily attached to a corner of the support 54. For example, the second insulator 18 could be attached to a second additional support, different from the support 54 and thus be kept in the air, for example on one side of the first antenna 2a or of the second antenna 2b opposite the first insulator 5.

Furthermore, the first antenna 2a and the second antenna 2b are not necessarily fixed on the same support. The first antenna 2a and the second antenna 2b could respectively be fixed on separate supports while extending in the same plane.

Claims (29)

Radiofrequency device (1) comprising: - a first set of antennas (2) comprising a first antenna (2a) and a second antenna (2b), the first antenna and the second antenna being flat in shape and both extending in the same first plane (3) , the first antenna being arranged to operate in a first frequency band, the second antenna being arranged to operate in a second frequency band; - a first insulator (5), the first insulator being flat in shape and extending in the first plane (3) between the first antenna (2a) and the second antenna (2b), the first insulator (5) comprising at least a branch which is electrically conductive, the first insulator being electrically floating, the first insulator being arranged to reduce a first coupling by electromagnetic radiation, between the first antenna and the second antenna, on the first frequency band and/or the second band of frequencies; the radio frequency device further comprising at least a second isolator (18) comprising at least one electrically conductive branch, the second isolator being electrically floating, the second isolator being positioned on one side of a particular antenna among the first antenna (2a) or the second antenna (2b), said side of the particular antenna being opposite the first insulator (5), the second insulator (18) being arranged to correct a change in directivity of the particular antenna caused by the presence of the first insulator . A radiofrequency device according to claim 1, the first frequency band and the second frequency band frequencies being separated by a frequency difference between 0MHz and 1GHz. Radiofrequency device according to one of the preceding claims, the first set of antennae (2) and the first insulator (5) being positioned on a support (4) made of a dielectric material, the support extending along the first plane ( 3). Radiofrequency device according to one of the preceding claims, the first insulator (5) comprising a first branch (6) and a second branch (7), both of which are electrically conductive, the second branch being substantially perpendicular to the first branch and extending from a central portion of the first branch, a free end (7a) of the second branch being in open circuit, the first insulator thus having a “T” shape. Radio frequency device according to claim 4, the first antenna (2a) and the second antenna (2b) being planar dipole antennas each having a rectangular shape, the first antenna being arranged to generate a first maximum electric field on a first axis (E _2a ), the second antenna being arranged to generate a second maximum electric field on a second axis (E _2b ), the first axis and the second axis being substantially parallel to each other. Radio frequency device according to claim 5, the first axis (E _2a ) and the second axis (E _2b ) being oriented substantially at 45 degrees with respect to the second branch (7). Radio frequency device according to claim 5, the first axis (E _2a ) and the second axis (E _2b ) being substantially perpendicular to the second branch (7). Radiofrequency device according to one of Claims 5 to 7, the first maximum electric field being greater than the second maximum electric field, one end (6a) of the first branch (6) of the first insulator being positioned at a distance of between 5 millimeters and 1.5 centimeters from the first axis (E _2a ). Radiofrequency device according to one of Claims 4 to 8, the first isolator (5) being arranged to reduce the first coupling by electromagnetic radiation more significantly on the first frequency band, the first branch (6) of the first isolator (5 ) having a predefined length substantially equal to at least a quarter of a first wavelength λ _A , the first wavelength λ _A being such that:

where ν ₁ is a first central frequency centered between a maximum frequency and a minimum frequency of the first frequency band, and εr is the dielectric permittivity of a medium in which the first insulator extends, the medium being a dielectric support or the air. Radiofrequency device according to one of Claims 4 to 8, the first isolator (5) being arranged to reduce the first coupling by electromagnetic radiation equally on the first frequency band and on the second frequency band, the first branch (6 ) of the first insulator (5) having a predefined length substantially equal to at least a quarter of a first wavelength λ _A , the first wavelength λ _A being such that:

where ν ₁ is a first center frequency centered between a maximum frequency and a minimum frequency of the first frequency band, ν ₂ is a second center frequency centered between a maximum frequency and a minimum frequency of the second frequency band and εr is the dielectric permittivity of a medium in which the first insulator extends, the medium being a dielectric support or air. Radiofrequency device according to one of Claims 9 or 10, the second branch (7) of the first isolator (5) having a predefined length substantially equal to a quarter of the first wavelength λ _A . Radiofrequency device according to one of Claims 4 to 11, the first branch (6) of the first insulator (5) having a predefined width so that the characteristic impedance of the said first branch is substantially equal to the characteristic impedance of an antenna selected from among the first antenna (2a) and the second antenna (2b), the second branch (7) of the first insulator (5) having a predefined width so that the characteristic impedance of said second branch is substantially equal to the characteristic impedance of the antenna selected from the first antenna (2a) and the second antenna (2b). Radiofrequency device according to one of Claims 4 to 11, the first branch (6) of the first insulator (5) having a predefined width so that the characteristic impedance of the said first branch is substantially between 75Ω and 120Ω, the second branch ( 7) of the first insulator (5) having a predefined width so that the characteristic impedance of said second branch is substantially between 75Ω and 120Ω. Radiofrequency device according to one of Claims 1 or 3, the first insulator (5) comprising three branches, all three of which are electrically conductive and arranged in such a way that the said first insulator has a "Y" shape. Radiofrequency device according to one of the preceding claims, the second insulator (18) comprising a single electrically conductive branch (19), said insulator thus having a longitudinal shape. Radiofrequency device according to one of the preceding claims, comprising a third antenna (20b) extending in a second plane (21), the second isolator (18) being further arranged to reduce a second coupling by electromagnetic radiation between the third antenna (20b) and the particular antenna, on a particular frequency band in which the particular antenna operates and on a third frequency band in which the third antenna (20b) operates. Radio frequency device according to claims 15 and 16, the second isolator (18) being arranged to reduce the second coupling by electromagnetic radiation more significantly on the particular frequency band, the branch (19) of the second isolator (18) having a length predefined substantially equal to half of a second wavelength λ _B , the second wavelength λ _B being such that:

where ν _# is a particular center frequency centered between a maximum frequency and a minimum frequency of the particular frequency band, and εr is the permittivity dielectric of a medium in which the second insulator extends, the medium being a dielectric support or air. Radio frequency device according to claims 15 and 16, the second isolator (18) being arranged to reduce the second coupling by electromagnetic radiation equally on the particular frequency band and on the third frequency band, the branch (19) of the second isolator (18) having a predefined length substantially equal to at least half of a second wavelength λ _B , the second wavelength λ _B being such that:

where ν _# is a particular center frequency centered between a maximum frequency and a minimum frequency of the particular frequency band, ν ₃ is a third center frequency centered between a maximum frequency and a minimum frequency of the third frequency band and εr is the dielectric permittivity of a medium in which the second insulator extends, the medium being a dielectric support or air. Radiofrequency device according to Claims 15 and 16, the branch (19) of the second insulator (18) having a predefined width so that the characteristic impedance of the said branch is substantially equal to the characteristic impedance of an antenna selected from among the antenna particular and the third antenna (20b). Radiofrequency device according to Claims 15 and 16, the branch (19) of the first insulator (18) having a predefined width so that the characteristic impedance of the said branch is substantially between 75Ω and 120Ω. Radiofrequency device according to one of Claims 16 to 20, the second isolator (18) being located near of an intersection of the first plane (3) and the second plane (21). A radiofrequency device according to claim 21, the second isolator (18) being positioned in a secant plane (22) at the first plane (3) and at the second plane (21). Radiofrequency device according to claim 21, the second isolator (18) forming a rounded corner (23) between the first plane (3) and the second plane (21). Radiofrequency device according to one of Claims 16 to 23, the first plane (3) and the second plane (21) being perpendicular. Radiofrequency device according to one of Claims 16 to 24, comprising a second set of antennas (20) comprising the third antenna (20b) and a fourth antenna (20a), and which is similar to the first set of antennas (2) , as well as a third insulator (33) similar to the first insulator (5) and positioned between the third antenna (20b) and the fourth antenna (20a). Radiofrequency device according to Claim 25, comprising a support (40) comprising four faces comprising two first faces (40a) parallel to each other and two second faces (40b) parallel to each other, two first sets of antennas (2) each positioned on a distinct first face (40a) and two second sets of antennas (20) each positioned on a distinct second face (40b), the radiofrequency device further comprising two first insulators (5) each positioned between the first antenna (2a) and the second antenna (2b) of a first distinct set of antennas (2), two third insulators (33) each positioned between a third antenna (20b) and a fourth antenna (20a) of a second set of antennas (20 ) distinct, as well as four second insulators (18) each positioned in a separate corner of the support (40). MIMO system (101) comprising a radiofrequency device according to one of Claims 25 or 26 as well as a radiofrequency transmitter (102) and a radiofrequency receiver (103) connected to the first sets of antennas (2) and to the second sets of antennas (20) of said radio frequency device. Electronic equipment (100) comprising a MIMO system (101) according to claim 27. Electronic equipment according to claim 28, the electronic equipment (100) being a residential gateway.

Images