Insulated radio frequency antenna device

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 planar 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) having 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

[0001] The invention relates to the field of radio frequency devices comprising a plurality of antennas. The invention is particularly applicable when the antennas operate in adjacent or even similar frequency bands. BACKGROUND OF THE INVENTION

[0002] Some recent electrical equipment, for example residential gateways (in English gateways These devices include multiple antennas to transmit and receive radio frequency signals in different frequency bands. To limit interference between antennas, it is essential to ensure that they are properly isolated from one another. This is particularly critical when the frequency bands used by the same device are adjacent (for example, 5GHz and 6GHz Wi-Fi) or even similar.

[0003] It is known to integrate filtering methods, such as analog electronic components, into the transmission and reception chains of radio frequency signals. However, such a solution impacts the transmitted or received radio frequency signals regardless of their propagation direction. Furthermore, this solution is generally inefficient when the frequency bands are adjacent.

[0004] Diversity techniques are also known, such as spatial diversity, polarization diversity, and radiation diversity. However, the performance of these techniques is generally limited when implemented in compact equipment. In particular, they cannot ensure omnidirectional propagation of radio frequency signals in multiple-input, multiple-output (MIMO) radio frequency systems. Multiple-Input Multiple-Output ) using adjacent frequency bands.

[0005] 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 are not very effective when integrated into a compact device.

[0006] Document KR 101 403 592 B1 describes a radio frequency device comprising three antennas and an insulator. SUBJECT OF THE INVENTION

[0007] One aim of the invention is to provide a compact radio frequency device that meets the isolation requirements set out above when adjacent frequency bands are used. SUMMARY OF THE INVENTION

[0008] To achieve this goal, 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 foreground, 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, the first insulator being planar in shape and extending in the foreground between the first antenna and the second antenna, the first insulator having 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 and the second antenna, on the first frequency band and / or the second frequency band;the radio frequency device further comprising at least one second insulator having 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 or second antenna, said side of the particular antenna being opposite the first insulator, the second insulator being arranged to correct a change in the directivity of the particular antenna caused by the presence of the first insulator.

[0009] The radio frequency device according to the invention is particularly advantageous because the arrangement of the first antenna and the second antenna, as well as the configuration of the first insulator which is not electrically connected to a ground plane between said antennas, ensures that the radio frequency device is compact while meeting the insulation requirements set out above.

[0010] According to a particular embodiment, the first frequency band and the second frequency band are separated by a frequency gap of between 0MHz and 1GHz.

[0011] 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.

[0012] According to a particular embodiment, the first insulator comprises a first branch and a second branch, both 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 an open circuit, the first insulator thus having a "T" shape.

[0013] 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 maximum electric field on a second axis, the first axis and the second axis being substantially parallel to each other.

[0014] According to a particular embodiment, the first axis and the second axis are oriented approximately at 45 degrees with respect to the second branch.

[0015] According to a particular embodiment, the first axis and the second axis are substantially perpendicular to the second branch.

[0016] 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 between 5 millimeters and 1.5 centimeters from the first axis.

[0017] According to a particular embodiment, the first isolator is arranged to reduce the first electromagnetic radiation coupling more significantly over the first frequency band, the first branch of the first isolator having a predefined length substantially equal to at least one quarter of a first wavelength λA, the first wavelength λA being such that: λ A = c ν 1 × εr where ν 1 is a first center 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 air.

[0018] According to a particular embodiment, the first isolator is arranged to reduce the first coupling by electromagnetic radiation equally over the first frequency band and over the second frequency band, the first branch of the first isolator having a predefined length substantially equal to at least one quarter of a first wavelength λA, the first wavelength λA being such that: λ A = c ν 1 + ν 2 2 × εr 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.

[0019] According to a particular embodiment, the second branch of the first insulator has a predefined length substantially equal to one quarter of the first wavelength λ A.

[0020] According to a particular embodiment, the first branch of the first insulator has a predefined width such that the characteristic impedance of said first branch is substantially equal to the characteristic impedance of an antenna selected from the first antenna and the second antenna, the second branch of the first insulator having a predefined width such that the characteristic impedance of said second branch is substantially equal to the characteristic impedance of the antenna selected from the first antenna and the second antenna.

[0021] According to a particular embodiment, the first branch of the first insulator has a predefined width such 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 such that the characteristic impedance of said second branch is substantially between 75Ω and 120Ω.

[0022] According to a particular embodiment, the first insulator comprises three branches, all three electrically conductive and arranged in such a way that said first insulator has a "Y" shape.

[0023] According to a particular embodiment, the second insulator comprises a single electrically conductive branch, the said insulator thus having a longitudinal shape.

[0024] According to a particular embodiment, the radio frequency device as previously described includes a third antenna extending in a second plane, the second insulator being further arranged to reduce a second electromagnetic radiation coupling 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.

[0025] According to a particular embodiment, the second isolator is arranged to reduce the second coupling by electromagnetic radiation more significantly over the particular frequency band, the branch of the second isolator having a predefined length substantially equal to half of a second wavelength λB, the second wavelength λB being such that: λ B = c ν # × εr where v# 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 air.

[0026] According to a particular embodiment, the second isolator is arranged to reduce the second coupling by electromagnetic radiation equally over the particular frequency band and over the third frequency band, the branch of the second isolator having a predefined length substantially equal to at least half of a second wavelength λB, the second wavelength λB being such that: λ B = c ν # + ν 3 2 × εr where v# 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.

[0027] According to a particular embodiment, the branch of the second insulator has a predefined width such 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.

[0028] 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 1200.

[0029] According to a particular embodiment, the second insulator is located near an intersection of the first plane and the second plane.

[0030] According to a particular embodiment, the second insulator is positioned in a plane intersecting the foreground and the background.

[0031] According to a particular embodiment, the second insulator forms a rounded corner between the first plane and the second plane.

[0032] According to a particular embodiment, the first plane and the second plane are perpendicular.

[0033] According to a particular embodiment, the radio frequency device as previously described comprises a second set of antennas including 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 insulator and positioned between the third antenna and the fourth antenna.

[0034] According to a particular embodiment, the radio frequency device as previously described comprises a support having four faces including two first faces parallel to each other and two second faces parallel to each other, two first sets of antennas each positioned on a distinct first face and two second sets of antennas each positioned on a distinct second face, the radio frequency device further comprising two first insulators each positioned between the first antenna and the second antenna of a distinct first set of antennas, two third insulators each positioned between a third antenna and a fourth antenna of a distinct second set of antennas, as well as four second insulators each positioned in a distinct corner of the support.

[0035] The invention also relates to a MIMO system comprising a radio frequency device as previously described and a radio frequency transmitter and a radio frequency receiver connected to the first sets of antennas and the second sets of antennas of said radio frequency device.

[0036] The invention also relates to electronic equipment comprising a MIMO system as previously described.

[0037] According to a particular embodiment, the electronic equipment is a residential gateway.

[0038] Other features and advantages of the invention will become apparent from the following description of particular, non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The description of embodiments refers to the attached drawings, which include: [ Fig. 1 ] there figure 1 represents 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 the figure 1 when the first antenna is transmitting and the first insulator is not present. Fig. 3 ] there figure 3 represents a simulation of the operation of the radio frequency device illustrated in the figure 1 when the first antenna is transmitting and the first insulator is present. Fig. 4 ] there figure 4 represents a simulation of the operation of the radio frequency device illustrated in the figure 1 when the second antenna is transmitting and the first insulator is not present. Fig. 5 ] there figure 5 represents a simulation of the operation of the radio frequency device illustrated in the figure 1 when the second antenna is transmitting and the first insulator 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 the figure 1 . [ Fig. 7 ] there figure 7 represents the radiation patterns of the first antenna of the radio frequency device illustrated in the figure 1 . [ Fig. 8 ] there figure 8 represents the radiation patterns of the second antenna of the radio frequency device illustrated in the figure 1 . [ Fig. 9 ] there figure 9 represents a perspective view of a first variant of the radio frequency device according to one embodiment. Fig. 10A ] there figure 10A illustrates a first position of the second isolator of the radio frequency device shown in the figure 9 . [ Fig. 10B ] there figure 10B illustrates a second position of the second isolator of the radio frequency device shown in the figure 9 . [ Fig. 11 ] there figure 11 represents a simulation of the electric field according to a first plane of the radiofrequency device illustrated in the figure 9 when the first antenna is transmitting and the first insulator is not present. Fig. 12 ] there figure 12 represents a simulation of the electric field according to a first plane of the radiofrequency device illustrated in the figure 9 when the first antenna is transmitting and the first insulator is present. Fig. 13 ] there figure 13 represents a simulation of the electric field according to a second plane of the radiofrequency device illustrated in the figure 9 when the first antenna is transmitting and the first insulator is not present. Fig. 14 ] there figure 14 represents a simulation of the electric field according to a second plane of the radiofrequency device illustrated in the figure 9 when the first antenna is transmitting and the first insulator 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 the figure 9 . [ Fig. 16 ] there figure 16 represents the radiation patterns of the first antenna of the radio frequency device illustrated in the figure 9 . [ Fig. 17 ] there figure 17 represents the radiation patterns of the third antenna of the radio frequency device illustrated in the figure 9 . [ Fig. 18 ] there figure 18 represents a relief view of a third variant of the radio frequency device according to one embodiment. Fig. 19 ] there figure 19 represents a simulation of the electric field of the radio frequency device illustrated in the figure 18 when the first antenna is transmitting and the isolation device is not present. Fig. 20 ] there figure 20 represents a simulation of the electric field of the radio frequency device illustrated in the figure 18 when the second antenna is transmitting and the isolation device is not present. Fig. 21 ] there figure 21 represents a simulation of the electric field of the radio frequency device illustrated in the figure 18 when the first antenna is transmitting and the isolation device is present. Fig. 22 ] there figure 22 represents a simulation of the electric field of the radio frequency device illustrated in the 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 illustrated in the figure 18 . [ Fig. 24 ] there figure 24 represents the combined gain radiation patterns of the second group of antennas of the radio frequency device illustrated in the figure 18 . [ Fig. 25 ] there figure 25 represents a block definition diagram of an electronic device integrating a MIMO system including the radio frequency device illustrated in the figure 18 . [ Fig. 26 ] there figure 26 represents a residential gateway integrating the radio frequency device illustrated in the figure 18 . DETAILED DESCRIPTION OF THE INVENTION

[0040] With reference to the figure 1 , a radio frequency device 1 is described according to an embodiment which is not included in the subject matter of the claims.

[0041] The radio frequency device 1 comprises a first set of antennas 2 including a first antenna 2a and a second antenna 2b. The first antenna 2a and the second antenna 2b are planar in shape and both extend in a first plane 3. The first plane 3 is defined by an X axis and by a Z axis, the X and Z axes being perpendicular.

[0042] The first antenna 2a and the second antenna 2b are here positioned on a support 4 made of a dielectric material and extending into the first plane 3. In this case, the support 4 is made of a plastic material having a dielectric permittivity greater than 1 (for example, the dielectric permittivity of the plastic material used is about equal to 3).

[0043] 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 radio frequency signals optimally in said frequency band (or respectively at said frequency).

[0044] Furthermore, the first and second frequency bands are distinct but adjacent. Here, "adjacent" means that the first and second frequency bands are separated by a frequency gap of approximately 0 MHz to approximately 1 GHz. For example, if the first frequency band is larger than the second frequency band, this frequency gap is the difference between the minimum frequency of the second frequency band and the maximum frequency of the first frequency band.

[0045] As an example, the first antenna 2a could be a dual-band antenna (in English dual-band ) operating at a frequency of 2.4GHz and a frequency of 5GHz, and the second antenna 2b could be a simple single-band antenna operating at a frequency of 6GHz.

[0046] As another example, the first antenna 2a could be a single-band antenna operating in a 5GHz frequency band, ranging from 5170MHz to 5835MHz, and the second antenna 2b could be a single-band antenna operating in a 6GHz frequency band, ranging from 5925MHz to 7125MHz.

[0047] The first antenna 2a and the second antenna 2b are planar dipole antennas mounted on rectangular supports. Both antennas exhibit an omnidirectional radiation pattern in the shape of a torus. The first antenna 2a generates a first maximum electric field along a first axis E2a, and the second antenna 2b generates a second maximum electric field along a second axis E2b. The first axis E2a is an axis of symmetry of the first antenna 2a, parallel to its width. The second axis E2b is an axis of symmetry of the second antenna 2b, parallel to its width.

[0048] Here, the first axis E 2a and the second axis E 2b are parallel.

[0049] The radio frequency device 1 further comprises a first insulator 5 of planar 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.

[0050] The first insulator 5 is positioned on the support 4 and fixed by means of fixing including for example riveting pins, glue or screws.

[0051] Still referring to the figure 1 , the first insulator 5 has 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 straight tracks made of a conductive material, for example aluminium, copper or iron.

[0052] Furthermore, the second branch 7 of the first insulator 5 is 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 that can be precisely cut (particularly in a metal plate) and is easily reproducible.

[0053] Thus, the first branch 6 of the first insulator 5 is a transmission line that is open-circuited between a first end 6a and a second end 6b. Furthermore, the second branch 7 of the first insulator 5 is a stub which is open-circuited at one 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 therefore a passive element that acts as a reciprocal band-stop resonator. The first insulator 5 thus exhibits a transmission coefficient that is the same regardless of the direction of flow of an electric current circulating through its first branch 6 and its second branch 7.

[0054] 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 prior art solutions. Indeed, according to the prior art, there are insulators mounted on PCBs (in English Printed Circuit Board ), but the use of a PCB (which notably has magnetic permeability) requires connecting said insulators to the electrical ground plane of said PCB.

[0055] The first axis E 2a and the second axis E 2b are both oriented here at an angle of 45 degrees with respect to the second branch 7 of the first insulator 5. The first axis E 2a extends directly to the vicinity of the first end 6a of the first branch 6 of the first insulator 5.

[0056] The dimensions of the first insulator 5 are predefined based on the available space, 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 dielectric permittivity) which impact the wavelengths, resonance frequencies, and characteristic impedances of the transmission lines (i.e., the tracks).

[0057] Preferably, the first branch 6 of the first insulator 5 has a length approximately equal to at least one quarter of a first wavelength λ A taking into account a medium in which the first insulator 5 extends.

[0058] In the first example, the first insulator 5 is designed to attenuate the electromagnetic radiation coupling 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 the first antenna 2a operates). If the medium in which the first insulator 5 extends is air, the first wavelength λA is calculated with a dielectric permittivity of 1. However, 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 λA is such that: λ A 4 = c 4 × ν 1 × ε r where εr is the dielectric permittivity of the material used to manufacture the dielectric support, and where ν₁ is a first center frequency centered between a maximum 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 center frequency ν₁ is approximately 5.5 GHz.

[0059] In another example, the first insulator 5 is designed to attenuate the electromagnetic radiation coupling between the first antenna 2a and the second antenna 2b in a balanced (or equal) manner between the first and second frequency bands. The first frequency band is, for example, the 5 GHz band, and the second frequency band is, for example, the 6 GHz band. If the medium in which the first insulator 5 extends is not air, then the first wavelength λA is such that: λ A 4 = c 4 × ν 1 + ν 2 2 × ε r where ν₁ is the first center frequency of the first frequency band (e.g., 5.5 GHz), and ν₂ is a second center frequency centered between a maximum and a minimum frequency of the second frequency band (e.g., 6.5 GHz). Further examples of sizing the first branch 6 of the first isolator 5 can be obtained depending on whether the isolation of the first or second frequency band is desired.

[0060] The second branch 7 of the first insulator 5 has a length approximately equal to one-quarter of the first selected wavelength λA. The first selected wavelength λA corresponds to a first selected frequency, which is, for example, equal to 6.2 GHz when isolation at the beginning of the so-called 6 GHz band (UNII-5) is required. The first selected frequency can also, for example, depend on the first center frequency ν1 of the first frequency band (in which the first antenna 2a operates) and the second center frequency ν2 of the second frequency band (in which the second antenna 2b operates). For example, the selected center frequency is equal to (ν1 + ν2) / 2.

[0061] In one example, the dimensions of the first insulator 5, in particular the respective widths of the first branch 6 and the second branch 7, are related to the characteristics of an antenna selected from the first antenna 2a and the second antenna 2b. The respective dimensions of the first antenna 2a and the second antenna 2b are considered in order to select the larger dimension(s). For example, when the first frequency band (in which the first antenna 2a operates) is the so-called 5 GHz band and the second frequency band (in which the second antenna 2b operates) is the so-called 6 GHz band, the radiating elements or tracks of the first antenna 2a have larger dimensions or sizes than the radiating elements or tracks of the second antenna 2b.The width of the radiating elements or tracks of the selected antenna determines the width of the first branch 6 and / or the second branch 7 of the first insulator 5. If the first frequency band (first antenna 2a) is the so-called 5GHz band and the second frequency band (second antenna 2b) is the so-called 6GHz band, the respective widths of the first branch 6 and the second branch 7 of the first insulator 5 can be on the order of 2.5mm-3mm.

[0062] 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, of a plastic material), the assembly (the PCB and the first dielectric support) having a dielectric permittivity of approximately 4.3. The first insulator 5 is, in one example, positioned on a second dielectric support (made, for example, of a plastic material) which may be identical or different from the first dielectric support on which the first antenna 2a is positioned, and having a dielectric permittivity of approximately 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 the second branch 7 of the first insulator 5 are approximately equal to the characteristic impedance of the first antenna 2a.

[0063] In various examples, the first branch 6 and the second branch 7 of the first insulator 5 have widths that ensure that their respective characteristic impedances are within the range [75Ω, 120Ω]. This maximizes the electric current flowing through the first branch 6 and the second branch 7, thereby maximizing the attenuation of the electromagnetic radiation coupling.

[0064] Furthermore, the first insulator 5 operates in the near field. Again, considering that the first insulator 5 is arranged to more significantly attenuate the electromagnetic radiation coupling between the first antenna 2a and the second antenna 2b in the first frequency band, the 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 optimally limits the intensity of the electric field generated by the first antenna 2a and received by the second antenna 2b. In another example, this distance is greater than 1 centimeter, for example, 1.5 centimeters.

[0065] THE figures 2 , 3, 4 et 5 They highlight the role of the first insulator 5 in the radio frequency device 1. The first antenna 2a is a Wi-Fi antenna operating in a frequency band from 5.1 GHz to 5.9 GHz. The second antenna 2b is a Wi-Fi antenna operating in a frequency band 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 therefore adjacent.

[0066] On each of the figures 2 , 3, 4 et 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 grey level.

[0067] With reference to figures 2 And 3The first antenna 2a is operating in transmit mode here, meaning it emits radio frequency signals within its frequency band. Field lines 8 therefore represent the orientation of the electric field generated by the first antenna 2a. Conversely, the second antenna 2b is inactive here, meaning it neither emits nor receives any radio frequency signals within its frequency band.

[0068] When the radio frequency device 1 does not include the first insulator 5 ( figure 2 The electric field generated by the first antenna 2a propagates unimpeded through the support 4 to the second antenna 2b. The second antenna 2b thus captures a significant portion of the electric field generated by the first antenna 2a. The field lines 8 are therefore concentrated on and in the vicinity of the second antenna 2b. Thus, given that the first antenna 2a and the second antenna 2b operate in adjacent frequency bands, the electromagnetic radiation coupling between the first antenna 2a and the second antenna 2b is significant.

[0069] When the radio frequency device 1 includes the first insulator 5 ( figure 3 The electric field generated by the first antenna 2a is filtered, that is, attenuated, by the reciprocal bandstop resonator function of the first insulator 5. The field lines 8 are thus concentrated on and in the vicinity of the first insulator 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 first end 6a of the first branch 6 of the first insulator 5 and at the free end 7a of the second branch 7 of the first insulator 5. The electromagnetic radiation coupling 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.

[0070] With reference to figures 4 et 5 The first antenna 2a is inactive here, and the second antenna 2b is transmitting. The field lines 9 therefore represent the orientation of the electric field generated by the second antenna 2b.

[0071] When the radio frequency device 1 does not include the first insulator 5 ( figure 4 The electric field generated by the second antenna 2b propagates unimpeded 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 electromagnetic radiation coupling between the first antenna 2a and the second antenna 2b is significant.

[0072] When the radio frequency device 1 includes the first insulator 5 ( figure 5 The field lines 9 are concentrated at the first end 6a and the second end 6b of the first branch 6 of the first insulator 5, and at 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 electromagnetic radiation coupling between the first antenna 2a and the second antenna 2b is therefore significantly reduced.

[0073] It should be noted that the first insulator 5 exhibits better performance when the first antenna 2a is transmitting (compared to the case where the second antenna 2b is transmitting). This result is logical because the first insulator 5 is sized here to operate near a maximum frequency of the first frequency band (ranging from 5.1 GHz to 5.9 GHz).

[0074] There figure 6 represents the amplitude in decibels of a parameter (in English Scattering Parameter S21 as a function of frequency. The parameter S21 corresponds to the transmission coefficient between the second antenna 2b and the first antenna 2a. Curve 10 represents the curve of the parameter S21 when the first insulator 5 is not present, and curve 11 represents the curve of the parameter S21 when the first insulator 5 is present. The first insulator 5 is sized here to attenuate the electromagnetic radiation coupling 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 insulator 5 reduces the amplitude of the parameter S21 in the frequency band for which it is sized. Indeed, a minimum reduction of approximately 5 dB in the amplitude of the parameter S21 is observed in the vicinity of a frequency of 5.5 GHz (reference R1 on the figure 6 ) and maximum reduction of approximately 34dB in the vicinity of a frequency equal to 6.3GHz (reference 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 designed.

[0075] With reference to figures 7 et 8 , here an axis Y is introduced, perpendicular to the axis X and to the axis Z such that the three axes X, Y, Z form an orthogonal Cartesian frame (3-dimensional space) defining three sections, a first section XZ (that is to say a section along the first plane 3), a second section YZ and a third section XY.

[0076] There figure 7 Figure 12 represents a radiation pattern of the first antenna 2a according to the first XZ section, a radiation pattern of the first antenna 2a according to the second YZ section, and a radiation pattern of the first antenna 2a according to the third XY section. The radiation patterns 12, 13, and 14 correspond to the case of figures 2 And 3 That is to say, the first antenna 2a is transmitting (in the first frequency band from 5.1 GHz to 5.9 GHz) and the second antenna 2b is inactive. It is common practice in the radio frequency domain to characterize an antenna using its radiation pattern, which represents the angular distribution (in degrees) of the antenna's gain (in isotropic decibels).

[0077] On 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 dashed line curve corresponds to the far-field directivity of the first antenna 2a when the first insulator 5 is present.

[0078] Radiation diagrams 12, 13, 14 highlight that the first insulator 5 modifies the far-field directivity of the first antenna 2a.

[0079] In particular, the radiation pattern 12 along the first XZ section shows that the far-field directivity 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 gain variation of the first antenna 2a is on the order of 8 dBi, whereas when the first insulator 5 is present (curve 12b), the maximum relative gain variation of the first antenna 2a is on the order of 3 dBi.

[0080] The radiation pattern 13 according to the second YZ section does not highlight a significant shift in the far-field directivity of the first antenna 2a.

[0081] 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 insulator 5 is not present (curve 14a), the gain of the first antenna 2a is maximum near an angle of 270 degrees, whereas when the first insulator 5 is present (curve 14b), the gain of the first antenna 2a is maximum near an angle of 180 degrees.

[0082] There figure 8 Figure 15 represents a radiation pattern of the second antenna 2b according to the first XZ section, a radiation pattern of the second antenna 2b according to the second YZ section, and a radiation pattern of the second antenna 2b according to the third XY section. Radiation patterns 15, 16, and 17 correspond to the case of figures 4 et 5 that is to say that the first antenna 2a is inactive and the second antenna 2b is transmitting (in the second frequency band from 5.9GHz to 7.2GHz).

[0083] On radiation diagrams 15, 16, 17, the solid line curve corresponds to the far-field directivity of the second antenna 2b when the first insulator 5 is not present and the dashed line curve corresponds to the far-field directivity of the second antenna 2b when the first insulator 5 is present.

[0084] Radiation diagrams 15, 16, and 17 highlight that the first insulator 5 has a moderate influence on the far-field directivity of the second antenna 2b. Indeed, the far-field directivity profile of the second antenna 2b when the first insulator 5 is not present is broadly similar to the far-field directivity profile of the second antenna 2b when the first insulator 5 is present. This is because the second axis E 2b of the second maximum electric field of the second antenna 2b does not extend directly into the vicinity of the first insulator 5.

[0085] It should be noted that the dimensions of the first isolator 5 can be adjusted according to a target frequency band.

[0086] 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.

[0087] Furthermore, 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.

[0088] With reference to the figure 9 The radio frequency device 1 according to one embodiment includes at least one second insulator 18. The radio frequency device 1 may also include only one second insulator 18.

[0089] The second insulator 18 is positioned on one side of a particular antenna, either the first antenna 2a or the second antenna 2b, said side of the particular antenna being opposite the first insulator. On the figure 9 The particular antenna is the first antenna 2a (which is this time positioned to the left of antenna 2b, not shown on the figure 9 ). The second insulator 18 is used to modify and reorient the far-field directivity of the first antenna 2a caused by the presence of the first insulator 5. The second insulator 18 is considered a parasitic element influencing the electric field mapping on the support 54.

[0090] The first antenna 2a is positioned here on a support 54 having 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 and Z axes. The second plane is therefore oriented at an angle Ω of 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 from 90 degrees.

[0091] The second insulator 18 is positioned here in a corner of the support 54 defined by an intersection of the first plane 3 and the second plane 21 via fixing means including for example rivet pins, glue or screws.

[0092] The second insulator 18 here comprises a single branch 19. This branch 19 of the second insulator 18 is formed by a flat, straight track made of a conductive material, for example, aluminum, copper, or iron. The second insulator 18 thus has an "I" or elongated shape. The "I" shape is simple and facilitates the manufacture of the second insulator 18 because it is a shape that can be precisely cut (particularly from a metal plate) and is easily reproducible.

[0093] Thus, branch 19 of the second insulator 18 is a transmission line which is open circuit between an end 19a and an end 19b. The second insulator is therefore a passive element.

[0094] Furthermore, 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 therefore electrically floating.

[0095] Still referring to the figure 9 It can be provided that the radio frequency device 1 also includes a third antenna 20b. The third antenna 20b is planar in shape and extends here in the second plane 21.

[0096] The third antenna, 20b, operates in a third frequency band. This third frequency band could be different from the first and second frequency bands, but it could also be similar to either the first or second frequency bands.

[0097] As an example, the third antenna 20b could be a single-band antenna operating in the so-called 6GHz band frequency range.

[0098] The third antenna 20b is a rectangular planar dipole antenna. Thus, the third antenna 20b exhibits an omnidirectional radiation pattern with a torus shape. The third antenna 20b generates a third maximum electric field along a third axis E 20b. The position of the third antenna 20b in the second plane 21 is therefore defined along the third axis E 20b.

[0099] With reference to the figure 9 , the second insulator 18 is positioned here in a corner of the support 54 between an antenna which is the first antenna 2a and the third antenna 20b.

[0100] With reference to the figure 10A , the second insulator 18 can be positioned in a plane intersecting 22 in the first plane 3 and in the second plane 21. The second insulator 18 is thus positioned at least partially on a chamfer of the support 54.

[0101] 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.

[0102] When placed between the first antenna 2a and the third antenna 20b, the second insulator 18 reduces electromagnetic radiation coupling between said first antenna 2a and said third antenna 20b.

[0103] The dimensions of the second isolator 18 are predefined according to the available space, the environment in which it is used and a frequency band in which its influence must be maximum.

[0104] The dimensions of the second insulator 18 are indicated here in the case where the second insulator 18 is arranged to isolate the third antenna 20b from the electric field generated by the first antenna 2a.

[0105] Preferably, the branch 19 of the second insulator 18 has a length approximately equal to half of a second wavelength λB taking into account a medium in which the second insulator 18 extends.

[0106] In the first example, the second insulator 18 is designed to attenuate the electromagnetic radiation coupling 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 λB is calculated with a dielectric permittivity of 1. However, 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 λB is such that: λ B 2 = c 2 × ν 1 × ε r , where εr is the dielectric permittivity of the material used for the manufacture of the dielectric support, where c is the speed of the electromagnetic wave, and where ν 1 is the first center frequency of the first frequency band in which the first antenna 2a operates.

[0107] In another example, the second insulator 18 is designed to attenuate the electromagnetic radiation coupling between the first antenna 2a and the third antenna 20b in a balanced (or equal) manner between the first and third frequency bands. The first frequency band is, for example, the 5 GHz band, and the third frequency band is, for example, the 6 GHz band. If the medium in which the second insulator 18 extends is not air, then the second wavelength λB is such that: λ B 2 = c 2 × ν 1 + ν 3 2 × ε r where ν₁ is the first center frequency of the first frequency band (e.g., 5.5 GHz), and ν₃ is a third center frequency centered between a maximum and a minimum frequency of the third frequency band (e.g., 6.5 GHz). Other examples of sizing branch 19 of the second isolator 18 can be obtained depending on whether the isolation of the first or third frequency band is required.

[0108] In one example, the dimensions of the second insulator 18, in particular the width of the branch 19, are related to the characteristics of an antenna selected from the first antenna 2a and the third antenna 20b. The respective dimensions of the first antenna 2a and 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 so-called 5 GHz band and the third frequency band (in which the third antenna 20b operates) is the so-called 6 GHz band, the radiating elements or tracks of the first antenna 2a have larger dimensions or sizes than the radiating elements or tracks of the third antenna 20b.The width of the radiating elements or tracks of the selected antenna (between the first antenna 2a and the third antenna 20b) allows us to determine the width of the branch 19 of the second insulator 18. If the first frequency band (first antenna 2a) is the frequency band known as the 5GHz band and the third frequency band (third antenna 20b) is the frequency band known as the 6GHz band, the width of the branch 19 of the second insulator 18 can be on the order of 2.5mm-3mm.

[0109] 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, of a plastic material), the assembly (the PCB and the first dielectric support) having a dielectric permittivity of approximately 4.3. The second insulator 18 is, in one example, positioned on a second dielectric support (made, for example, of a plastic material) which may be identical or different from the first support on which the first antenna 2a is positioned, and having a dielectric permittivity of approximately 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 characteristic impedance of the first antenna 2a.

[0110] In various examples, the branch 19 of the second insulator 18 has a width that ensures that the characteristic impedance of said branch 19 is within the range [75Ω, 120Ω]. This maximizes the electric current flowing through said branch 19 and thus maximizes the attenuation of the coupling by electromagnetic radiation.

[0111] In another example, the width of branch 19 of the second insulator 18 is at least equal to the width of the first branch 6 and / or the second branch 7 of the first insulator 5. In yet another example, the width of branch 19 of the second insulator 18 is approximately equal to twice the width of the first branch 6 and / or the second branch 7 of the first insulator 5.

[0112] Furthermore, the second insulator 18 operates in the near field. Again, considering that the second insulator 18 is arranged here to isolate the third antenna 20b from the electric field generated by the first antenna 2a, the distance between the second insulator 18 and the first axis E 2a is between 5 millimeters and 1 centimeter. This distance optimally limits the intensity of the electric field generated by the first antenna 2a and received by the third antenna 20b. In another example, this distance is greater than 1 centimeter, for example, 1.5 centimeters.

[0113] THE figures 11 , 12 , 13 And 14They highlight the role of the second insulator 18 in the radio frequency device 1. The first antenna 2a is a Wi-Fi antenna operating in a frequency band from 5.1 GHz to 5.9 GHz, that is, in the so-called 5 GHz band. The third antenna 20b is a Wi-Fi antenna operating in a frequency band from 5.9 GHz to 7.2 GHz, that is, in the so-called 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.

[0114] On each of the figures 11 , 12 , 13 And 14 The 24 curved field lines represent the orientation of the electric field in the first plane 3 and in the second plane 21. Furthermore, the intensity of said electric field (in Vm⁻¹) is represented here in grayscale. The first antenna 2a is operating in transmit mode, and the third antenna 20b is inactive.

[0115] THE figures 11 And 12 represent the orientation and intensity of the electric field generated by the first antenna 2a in the first plane 3.

[0116] THE figures 13 And 14 represent the orientation and intensity of the electric field generated by the first antenna 2a in the second plane 21.

[0117] When the radio frequency device 1 does not include the second insulator 18, the electric field generated by the first antenna 2a propagates through the support 54 along the first axis E 2a ( figure 11 ). Furthermore, the field lines 24 are concentrated at the third antenna 20b, which shows that said third antenna 20b captures a significant portion of the electric field generated by the first antenna 2a ( figure 13 ).

[0118] When the radio frequency device 1 includes the second insulator 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 ends 19a and 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., their orientation when the second insulator 18 is not present). This deflection of the field lines 24 also attenuates the portion of the electric field generated by the first antenna 2a that is received by the third antenna 20b. The second insulator 18 thus reduces the electromagnetic radiation coupling between the first antenna 2a and the third antenna 20b.

[0119] There figure 15 represents the amplitude in decibels of the parameter S21 as a function of frequency. The parameter S21 corresponds to the transmission coefficient between the third antenna 20b and the first antenna 2a. Curve 25 represents the curve of the parameter S21 when the second insulator 18 is not present, and curve 26 represents the curve of the parameter S21 when the second insulator 18 is present. The second insulator 18 is sized here to attenuate the electromagnetic radiation coupling between the first antenna 2a and the third antenna 20b in a frequency band ranging from 5 GHz to 7 GHz. The second insulator 18 slightly reduces the amplitude of the parameter S21 in the frequency band for which it is sized. Indeed, a maximum reduction of approximately 8 dB is observed in the vicinity of a frequency equal to 5.2 GHz (reference R3 on the figure 15 ). The second insulator 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 designed.

[0120] There figure 16 Figure 27 represents a radiation pattern of the first antenna 2a according to the first XZ section, a radiation pattern of the first antenna 2a according to the second YZ section, and a radiation pattern of the first antenna 2a according to the third XY section. The radiation patterns 27, 28, and 29 correspond to the case of figures 11 , 12 , 13 , 14 that is to say that the first antenna 2a is transmitting (in the first frequency band from 5.1GHz to 5.9GHz) and the third antenna 20b is inactive.

[0121] On radiation diagrams 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 dashed line curve corresponds to the far-field directivity of the first antenna 2a when the second insulator 18 is present.

[0122] Radiation diagrams 27, 28, 29 highlight that the second insulator 18 modifies the far-field directivity of the first antenna 2a.

[0123] In particular, the radiation pattern 27 according to the first XZ section shows that the far-field directivity of the first antenna 2a is generally more homogeneous when the second insulator 18 is present (curve 27b). More precisely, when the second insulator 18 is not present (curve 27a), the maximum relative gain variation of the first antenna 2a is on the order of 7 dBi, whereas when the second insulator 18 is present (curve 27b), the maximum relative gain variation of the first antenna 2a is on the order of 5 dBi.

[0124] The radiation pattern 28 according to the third XY section shows that the maximum gain of the first antenna 2a is shifted when the second insulator 18 is present. Indeed, when the second insulator 18 is not present (curve 28a), the gain of the first antenna 2a is maximum for an angle range from 210 degrees to 300 degrees, whereas when the second insulator 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.

[0125] There figure 17 Figure 30 represents a radiation pattern of the third antenna 20b according to the first XZ section, a radiation pattern of the third antenna 20b according to the second YZ section, and a radiation pattern of the third antenna 20b according to the third XY section. Radiation patterns 30, 31, and 32 correspond to the case in which the third antenna 20b is transmitting (in the third frequency band from 5.9 GHz to 7.2 GHz).

[0126] On radiation diagrams 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 dashed line curve corresponds to the far-field directivity of the third antenna 20b when the second insulator 18 is present.

[0127] Radiation diagrams 30, 31, and 32 demonstrate that the second insulator 18 has a negligible influence on the far-field directivity of the third antenna 20b. Indeed, the far-field directivity profiles and gain values ​​of the third antenna 20b are broadly similar when the second insulator 18 is absent and when it is present. This is because the third axis E 20b of the third maximum electric field of the third antenna 20b does not extend directly into the vicinity of the second insulator 18.

[0128] 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-directing element.

[0129] It should be noted that the dimensions of the first insulator 5 and / or the second insulator 18 can be adjusted according to a target frequency band.

[0130] 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.

[0131] With reference to the figure 18 The radio frequency device 1 further comprises a second set of antennas 20 including the third antenna 20b and a fourth antenna 20a. The second set of antennas 20 is 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.

[0132] The third antenna 20b and the fourth antenna 20a extend into the second plane 21 and are positioned on the support 54.

[0133] A third insulator 33, similar to the first insulator 5, is positioned between the third antenna 20b and the fourth antenna 20a. The third insulator 33 is thus arranged to reduce electromagnetic radiation coupling between the third antenna 20b and the fourth antenna 20a.

[0134] With reference to the figure 18 , it is also planned that the radio frequency device 1 will include two first sets of antennas 2, two second sets of antennas 20, two first insulators 5, two third insulators 33 and four second insulators 18.

[0135] The radio frequency device 1 is mounted on a cylindrical support 40 with a square cross-section (with slightly rounded corners). The cylindrical support 40 has two first faces 40a, which are parallel to each other; and two second faces 40b, which are also parallel to each other. The cylindrical support 40 thus has four corners 41, 42, 43, 44. Overall, the cylindrical support 40 has the shape of a rectangular ring.

[0136] Preferably, the cylindrical support 40 is made of a material having a dielectric permittivity greater than 1. For example, the cylindrical support 40 is made of a plastic material or of a polymer material.

[0137] 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.

[0138] 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.

[0139] A second insulator 18 is positioned on each of the four corners, 41, 42, 43, 44 of the cylindrical support 40.

[0140] A first group of antennas G1 and a second group of antennas G2 are defined.

[0141] The first antenna group G1 comprises the first antenna 2a from each of the first two antenna sets 2 and the fourth antenna 20a from each of the second two antenna sets 20. The first antenna group G1 thus consists of four antennas. The antennas in group G1 are dual-band Wi-Fi antennas operating in the 2.4 GHz and 5 GHz frequency bands. In another example, the antennas in group G1 are 802.11 antennas, single-band, and operate in the 5 GHz frequency band. In yet another example, the antennas in group G1 are 802.11 antennas, single-band, and operate in the 6 GHz frequency band.In yet another example, the G1 group antennas are tri-band antennas comprising different subsets of electrical conductors enabling said G1 group antennas to operate simultaneously in the frequency band known as the 2.4GHz band, in the frequency band known as the 5GHz band and in the frequency band known as the 6GHz band.

[0142] The second antenna group G2 comprises the second antenna 2b from each of the first two antenna sets 2 and the third antenna 20b from each of the second two antenna sets 20. The second antenna group G2 thus consists of four antennas. The antennas in group G2 are single-band Wi-Fi antennas operating in the 6 GHz frequency band.

[0143] Furthermore, in the remainder of the description, the first two insulators 5, the two third insulators 33 and the four second insulators 18 will be designated as an isolation device

[0144] THE figures 19, 20 , 21, 22 highlight the role of the first insulator 5, the second insulator 18 and the third insulator 33 in the radio frequency device 1. The first antenna 2a which belongs to the first antenna group G1 is here in transmission.

[0145] 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 Vm-1.

[0146] On the figures 19 And 21 , the first antenna 2a (belonging to the first group of antennas G1) is transmitting and the other antennas are inactive.

[0147] When the insulation device is not present ( figure 19 ), part of the electric field generated by the first antenna 2a is captured by the other antennas, and in particular by the second antenna 2b.

[0148] When the insulation device is present ( figure 21 ), the electric field generated by the first antenna 2a is captured by the isolation device, here in particular by the first insulator 5. The electromagnetic radiation coupling between the antennas of the radio frequency device 1 is thus greatly reduced.

[0149] On the figures 20 And 22 , the second antenna 2b (belonging to the second group of antennas G2) is transmitting and the other antennas are inactive.

[0150] When the insulation device is not present ( figure 20 ), part of the electric field generated by the second antenna 2b is captured by the other antennas, and in particular by the first antenna 2b and the fourth antenna 20a ( figure 22 ).

[0151] When the insulation device is present ( figure 22 ), the electric field generated by the second antenna 2b is captured by the isolation device, here in particular by the second insulator 18. The electromagnetic radiation coupling between the antennas of the radio frequency device 1 is thus greatly reduced.

[0152] There figure 23 Figure 46 represents a radiation pattern according to the first XZ section, a radiation pattern 47 according to the second YZ section, and a radiation pattern 48 according to the third XY section of the antennas in the first antenna group G1. More precisely, radiation patterns 46, 47, and 48 are here average combined gain radiation patterns.

[0153] On radiation diagrams 46, 47, 48, the solid line curve corresponds to the combined far-field directivity of the antennas in the first antenna group G1 when the isolation device is not present and the dashed line curve corresponds to the combined far-field directivity of the antennas in the first antenna group G1 when the isolation device is present.

[0154] Radiation diagrams 46, 47, 48 highlight that the isolation device makes it possible to substantially homogenize the far-field directivity of the antennas of the first group of antennas G1.

[0155] There figure 24 Figure 49 represents a radiation pattern according to the first XZ section, a radiation pattern 50 according to the second YZ section, and a radiation pattern 51 according to the third XY section of the antennas in the second antenna group G2. More precisely, radiation patterns 49, 50, and 51 are here average combined gain radiation patterns.

[0156] On radiation diagrams 49, 50, 51, the solid line curve corresponds to the combined far-field directivity of the antennas of the second antenna group G2 when the isolation device is not present and the dashed line curve corresponds to the combined far-field directivity of the antennas of the second antenna group G2 when the isolation device is present.

[0157] Radiation diagrams 49, 50, 51 highlight that the isolation device has a limited influence on the far-field directivity of the antennas in the second antenna group G2.

[0158] 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.

[0159] The radio frequency device 1 according to one embodiment therefore makes it possible to meet the isolation constraints between antennas when adjacent frequency bands are used while ensuring 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).

[0160] Furthermore, the radio frequency device does not require any special antenna technology (e.g., ceramic antennas) and can be implemented using antennas with conventional dimensions.

[0161] With reference to the figure 25 , the radio frequency device 1 according to one embodiment is here integrated into a MIMO 101 system (in English Multiple-Input Multiple-Output ) which itself is integrated into an electronic device 100. The MIMO system 101 comprises a radio frequency transmitter 102 and a radio frequency receiver 103, both of which are connected to the radio frequency device 1 in various embodiments, such as 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 radio frequency device 1. The radio frequency receiver 103 is arranged to receive electrical signals from radio frequency signals received by the radio frequency device 1.

[0162] With reference to the figure 26 The radio frequency device 1 is integrated in particular into an electronic device 100 which is a residential gateway. The residential gateway here has a tower shape.

[0163] 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.

[0164] The radio frequency device according to embodiments is beneficially applicable to any electronic equipment requiring the combination of multiple radio frequency interfaces (in particular communication technologies using different but adjacent frequency bands) and / or requiring the provision of multiple transmission paths on the same frequency band, all within a small space.

[0165] It should be noted that the first insulator 5 here has a "T" shape, but it is entirely possible for the first insulator 5 to have another shape. For example, the first insulator 5 could have three electrically conductive branches arranged so that said first insulator 5 has a "Y" shape. More broadly, the shape of the first insulator 5 can be adapted according to, for example, the specified performance of the radio frequency device 1. The same applies to the third insulator 33, which is similar to the first insulator 5.

[0166] Similarly, the second insulator 18 here has an "I" shape, but it is entirely possible that the second insulator 18 could have a different shape. It should be noted that the shape of the second insulator 18 can be adapted according to, for example, the specified performance of the radio frequency device 1.

[0167] It should be noted that the first insulator 5 is not necessarily fixed to the same support as the first antenna 2a and the second antenna 2b. For example, the first insulator 5 could be fixed to a separate support, different from support 4 or support 54, and thus be suspended between the first antenna 2a and the second antenna 2b. The same applies to the third insulator 33, which is similar to the first insulator 5. Therefore, the third insulator 33 is not necessarily fixed to the same support as the third antenna 20b and the fourth antenna 20a.

[0168] Similarly, the second insulator 18 is not necessarily fixed to a corner of the support 54. For example, the second insulator 18 could be fixed to a second auxiliary support, different from the support 54 and thus be held in the air for example on one side of the first antenna 2a or the second antenna 2b opposite the first insulator 5.

[0169] Furthermore, the first antenna 2a and the second antenna 2b are not necessarily fixed to the same support. The first antenna 2a and the second antenna 2b could be fixed to separate supports while extending in the same plane.

Claims

1. An RF device (1) comprising: · a first antenna set (2) comprising a first antenna (2a) and a second antenna (2b), the first and second antennas being planar in shape and both lying in a common first plane (3), the first antenna being arranged to operate in a first frequency band and the second antenna being arranged to operate in a second frequency band; · a first isolator (5), the first isolator being planar in shape and lying in the first plane (3) between the first and second antennas (2a, 2b), the first isolator (5) having at least one branch that is electrically conductive, the first isolator being electrically floating, the first isolator being arranged to reduce first coupling by electromagnetic radiation between the first and second antennas in the first frequency band and / or in the second frequency band; · the RF device further comprising at least one second isolator (18) having at least one electrically conductive branch, the second isolator being electrically floating, the second isolator being positioned on one side of a particular antenna selected from the first and second antennas (2a, 2b), said side of the particular antenna being remote from the first isolator (5), the second isolator (18) being arranged to correct a modification to the directivity of the particular antenna as caused by the presence of the first isolator.

2. An RF device according to claim 1, the first and second frequency bands being separated by a frequency gap lying in the range approximately 0 MHz to approximately 1 GHz.

3. An RF device according to either preceding claim, the first antenna set (2) and the first isolator (5) being positioned on a support (4) made out of a dielectric material, the support lying in the first plane (3).

4. An RF device according to any preceding claim, the first isolator (5) having first and second branches (6, 7) that are both electrically conductive, the second branch being substantially perpendicular to the first branch and projecting from a central portion of the first branch, a free end (7a) of the second branch being open circuit, the first isolator thus being T-shaped.

5. An RF device according to claim 4, the first and second antennas (2a, 2b) being planar dipole antennas, each being rectangular in shape, the first antenna being arranged to generate a first maximum electric field along a first axis (E2a), the second antenna being arranged to generate a second maximum electric field along a second axis (E2b), and the first and second axes being substantially parallel to each other.

6. An RF device according to claim 5, the first and second axes (E2a, E2b) being oriented at substantially 45° relative to the second branch (7).

7. An RF device according to claim 5, the first and second axes (E2a, E2b) being substantially perpendicular to the second branch (7).

8. An RF device according to any 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 isolator being spaced apart from the first axis (E2a) by a distance lying in the range 5 mm to 1.5 cm.

9. An RF device according to any one of claims 4 to 8, the first isolator (5) being arranged to reduce the first coupling by electromagnetic radiation to a greater extent in the first frequency band, the first branch (6) of the first isolator (5) having a predefined length that is substantially equal to at least one quarter of a first wavelength λA, the first wavelength λA being such that: λ A = c ν 1 × εr where ν1 is a first center frequency centered between the maximum frequency and the minimum frequency of the first frequency band, and where εr is the dielectric permittivity of the medium in which the first isolator lies, the medium being a dielectric support or air.

10. An RF device according to any one of claims 4 to 8, the first isolator (5) being arranged to reduce the first coupling by electromagnetic radiation in equal manner in the first and second frequency bands, the first branch (6) of the first isolator (5) having a predefined length that is substantially equal to at least one quarter of a first wavelength λA, the first wavelength λA being such that: λ A = c ν 1 + ν 2 2 × εr where ν1 is a first center frequency centered between the maximum frequency and the minimum frequency of the first frequency band, where ν2 is a second center frequency centered between the maximum frequency and the minimum frequency of the second frequency band, and where εr is the dielectric permittivity of the medium in which the first isolator lies, the medium being a dielectric support or air.

11. An RF device according to claim 9 or claim 10, the second branch (7) of the first isolator (5) having a predefined length that is substantially equal to one quarter of the first wavelength λA.

12. An RF device according to any one of claims 4 to 11, the first branch (6) of the first isolator (5) having a width that is predefined so that the characteristic impedance of said first branch is substantially equal to the characteristic impedance of one antenna selected from the first and second antennas (2a, 2b), the second branch (7) of the first isolator (5) having a width that is predefined so that the characteristic impedance of said second branch is substantially equal to the characteristic impedance of the antenna selected from the first and second antennas (2a, 2b).

13. An RF device according to any one of claims 4 to 11, the first branch (6) of the first isolator (5) having a width that is predefined so that the characteristic impedance of said first branch lies substantially in the range 75 Ω to 120 Ω, the second branch (7) of the first isolator (5) having a width that is predefined so that the characteristic impedance of said second branch lies substantially in the range 75 Ω to 120 Ω.

14. An RF device according to claim 1 or claim 3, the first isolator (5) having three branches that are all electrically conductive and that are arranged in such a manner that said first isolator is Y-shaped.

15. An RF device according to any preceding claim, the second isolator (18) having a single electrically conductive branch (19), said isolator thus having a shape that is longitudinal.

16. An RF device according to any preceding claim, having a third antenna (20b) extending in a second plane (21), the second isolator (18) also being arranged to reduce second coupling by electromagnetic radiation between the third antenna (20b) and the particular antenna over a particular frequency band in which the particular antenna operates and over a third frequency band in which the third antenna (20b) operates.

17. An RF device according to claim 16, the second isolator (18) being arranged to reduce the second coupling by electromagnetic radiation to a greater extent in the particular frequency band, the single branch (19) of the second isolator (18) having a predefined length that is substantially equal to half a second wavelength λB, the second wavelength λB being such that: λ B = c ν # × εr where ν# is a particular center frequency centered between the maximum frequency and the minimum frequency of the particular frequency band, and where εr is the dielectric permittivity of the medium in which the second isolator lies, the medium being a dielectric support or air.

18. An RF device according to claim 16, the second isolator (18) being arranged to reduce the second coupling by electromagnetic radiation in equal manner in the particular frequency band and in the third frequency band, the single branch (19) of the second isolator (18) having a predefined length that is substantially equal to half a second wavelength λB, the second wavelength λB being such that: λ B = c ν # + ν 3 2 × εr where ν# is a particular center frequency centered between the maximum frequency and the minimum frequency of the particular frequency band, where ν3 is a third center frequency centered between the maximum frequency and the minimum frequency of the third frequency band, and where εr is the dielectric permittivity of the medium in which the second isolator lies, the medium being a dielectric support or air.

19. An RF device according to claims 15 and 16, the branch (19) of the second isolator (18) having a width that is predefined 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 (20b).

20. An RF device according to claims 15 and 16, the branch (19) of the second isolator (18) having a width that is predefined so that the characteristic impedance of said branch lies substantially in the range 75 Ω to 120 Ω.

21. An RF device according to any one of claims 16 to 20, the second isolator (18) being situated in the proximity of an intersection between the first and second planes (3, 21).

22. An RF device according to claim 21, the second isolator (18) being positioned in an intersecting plane (22) that intersects the first and second planes (3, 21).

23. An RF device according to claim 21, the second isolator (18) forming a rounded corner (23) between the first and second planes (3, 21).

24. An RF device according to any one of claims 16 to 23, the first and second planes (3, 21) being perpendicular.

25. An RF device according to any one of claims 16 to 24, including a second antenna set (20) comprising the third antenna (20b) and a fourth antenna (20a), the second antenna set being similar to the first antenna set (2), and also including a third isolator (33) similar to the first isolator (5) and positioned between the third and fourth antennas (20b, 20a) .

26. An RF device according to claim 25, comprising a support (40) having four faces comprising two mutually parallel first faces (40a) and two mutually parallel second faces (40b), two first antenna sets (2) each positioned on a distinct first face (40a), and two second antenna sets (20) each positioned on a distinct second face (40b), the RF device further comprising two first isolators (5) each positioned between the first and second antennas (2a, 2b) of a distinct first antenna set (2), two third isolators (33) each positioned between a third antenna (20b) and a fourth antenna (20a) of a distinct second antenna set (20), and four second isolators (18) each positioned in a distinct corner of the support (40).

27. A MIMO system (101) including an RF device according to claim 25 or claim 26 together with an RF transmitter (102) and an RF receiver (103) both connected to the first and second antenna sets (2, 20) of said RF device.

28. Electronic equipment (100) including a MIMO system (101) according to claim 27.

29. Electronic equipment according to claim 28, the electronic equipment (100) being a residential gateway.

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