Device for controlling RF electromagnetic beams according to their angle of incidence and manufacturing method

Abstract

A radiofrequency beam control device (10) is proposed comprising a set of cells (100). Each cell comprises a support frame (130) and an excitation element (150), and carries out beam emission and / or reception invariant according to the beam propagation direction. The frame is inscribed in a generally tubular shape, oriented along the Z axis of a reference frame (X,Y,Z), having a cross-section of perimeter P, and comprises an inlet (131), an outlet (132) and a number N of slots (133-n) between the outlet and a position Zo located between the inlet and the outlet. Each slot has a variable width along Z. The slot width has a minimum value at the position Zo, and a maximum value at the outlet determined as a function of the perimeter P and the number N. Figure for abstract: [Fig.3]

Description

Title of the invention: Device for controlling RF electromagnetic beams according to their angle of incidence and manufacturing method Technical field

[0001] The present invention relates generally to the field of radio frequencies (RF), and in particular to a device for controlling RF electromagnetic beams, in particular for controlling the emission and / or reception of electromagnetic beams according to an angle of incidence of the beam relative to the device, as well as a method for manufacturing such a device.

[0002] It is known to use beam control devices, originating from sources of RF electromagnetic signals, consisting of an array of small radiating elements in which an RF electromagnetic wave circulates, as described for example in patent application FR3117685A1. Such devices, generally planar, are configured to emit and / or receive electromagnetic beams characterized by a direction forming an angle of incidence of the beam relative to the planar device. Each radiating element (and thus the induced device) can be characterized by an active impedance.

[0003] In such devices, there is significant mutual coupling between adjacent RF electromagnetic waves of the same array. The mutual coupling between radiating elements contributes to modifying, depending on the angle of incidence of a beam with respect to the device, the active impedance of the radiating elements and thus significantly limits the RF beam transmission performance of a device over a low-elevation angular sector and / or over certain specific directions, called “blinding directions”, as described for example in the article “Mutual impedance effects in large beam scanning arrays” by P. Carter et al., IRE Transactions on Antennas and Propagation, vol. 8, no. 3, 1960, pages. 276-285.

[0004] Some known solutions, called adaptation solutions, are used to stabilize the active impedance of a control device according to the beam propagation direction. These adaptation solutions include for example the implementation of WAIM screens (acronym for Wide Angle Impedance Matching) as described for example in the article “Wide-angle impedance matching of a planar array antenna by a dielectric sheet” by E. Magill et al., IEEE Transactions on Antennas and Propagation, vol. 14, no. 1, 1966, pages. 49-53, or in the article “Wide angle impedance matching metamaterials for waveguide-fed phased-array antennas” by S. Sajuyigbe et al., IET Microwaves, Antennas & Propagation, vol. 4, no. 8, 2010, pp. 1063-1072. Other known matching solutions include the use of dipoles strongly coupled to each other by interdigital capacitors, as described in the article “The Planar Ultrawideband Modular Antenna (PUMA) Array” by SS Holland et al., IEEE TAP, vol. 60, no. 1, 2012, pp. 130-140. However, the design of these matching solutions is complex, and their manufacturing includes many constraints, such as the implementation of dielectric substrate-based technologies, which may induce ohmic losses in the compatible bandwidth frequencies of the telecommunication system.

[0005] There is thus a need for an improved device for controlling RF electromagnetic wave beams over a wide angular beam misalignment sector relative to the device and for reducing blinding directions, via a solution for improving the stability of the active impedance of the device. Summary of the invention

[0006] The present invention improves the situation by proposing a device for controlling radiofrequency beams defined in an orthogonal frame (X,Y,Z). The device generally extends in the plane (X,Y) of the orthogonal frame (X,Y,Z). The device comprises a set of at least one cell corresponding to a radiating element. The cell comprises a support frame and an excitation element of the radiating element, each radiofrequency beam being defined according to a given propagation direction having an angle of incidence θ relative to the device. The support frame is inscribed in a generally tubular shape oriented along the Z axis of the orthogonal frame (X,Y,Z). The tubular shape has a length dz given along the axis of the frame Z and a cross-section defined in the plane (X,Y). The cross-section has a perimeter P, the support frame comprises a frame entrance and a frame exit.The support frame further comprises a number N of slots extending, along the frame axis Z, between the frame outlet and a slot position ZOn along the frame axis Z. The slot position ZOn is located between the frame inlet and the frame outlet, each slot has a slot width ®n variable along the frame axis Z. The slot width ®n has a minimum slot value Cùn®1 at the slot position ZOdl, and a maximum slot value Cû]]1^ at the frame outlet, the maximum slot value œ“iax being determined as a function of the perimeter P of the cross-section and the number N of slots. Each cell is configured to carry out transmission and / or reception of radiofrequency beams invariant according to the propagation direction.

[0007] Each slot may be associated with at least two slot edges, the slot edges representing the boundaries of the support frame connecting the slot position Z^ to the output of frame. Each slot edge can be associated with a variability function, the variability function being a concave and / or convex polygonal function.

[0008] In embodiments, the excitation element may comprise a number H of longitudinal metal ribs arranged within the tubular shape. A rib may extend along the frame axis Z between the frame inlet and a rib position Z^. The rib position Z];1 may be defined between the frame inlet and the frame outlet.

[0009] In particular, the number H of ribs can be equal to the number N of slots.

[0010] The ribs of the cell may be identical to each other and the slots of the cell can be identical to each other. The rib position Z^ can be defined between the slot position ZOn and the frame exit.

[0011] In embodiments, the excitation element may comprise a so-called "Vivaldi" antipodal transition arranged at least partly within the tubular shape. The transition may comprise at least a first metal etch and a second metal etch extending along the frame axis Z between the frame entrance and an etch position Zgg. The etch position Zpg may be defined between the frame entrance and the frame exit.

[0012] In embodiments, the excitation element may comprise a number T of planar metallic elements arranged within the tubular shape, one planar element extending along the (X,Y) plane at a planar position Zt. The planar position Zt may be defined between the frame entrance and the frame exit.

[0013] The slots of the cell can be identical to each other, the planar position Zt being defined between the slot position ZOn and the frame exit.

[0014] The device may be partly metallic. The cross-section may have the shape of a circle or a polygon.

[0015] The invention also provides a method of manufacturing the radiofrequency beam control device characterized in that the device is at least partially metallic, and the manufacturing method uses at least one 3D printing technique.

[0016] The device according to the embodiments of the invention makes it possible to control beams of RF electromagnetic waves according to a wide angular sector of beam misalignment relative to the device and a reduction in blinding directions, thanks to an improvement in the stability of the active impedance of the device.

[0017] Such a device is particularly suitable for RF bandwidths compatible with telecommunications antenna systems. It also provides an efficient solution, while limiting manufacturing complexity and costs, and makes it possible to obtain reduced weight and significant compactness. In particular, in the space sector, such a device does not impact the satellite payload. Description of figures

[0018] Other characteristics, details and advantages of the invention will emerge from reading the description given with reference to the appended drawings given by way of example.

[0019] [Fig.l] [Fig.l] is a diagram showing a radiofrequency beam control device, according to embodiments of the invention.

[0020] [Fig.2] [Fig.2] is a diagram representing an antenna system, according to modes of carrying out the invention.

[0021] [Fig.3] [Fig.3] is a diagram showing the support frame of a cell of the radiofrequency beam control device, according to embodiments of the invention.

[0022] [Fig.4] [Fig.4] is a perspective view of a cell of the control device of radio frequency beams showing the support frame and internal ribs of the cell, according to embodiments of the invention.

[0023] [Fig.5] [Fig.5] is a perspective view of a cell of the control device of radio frequency beams showing the support frame and an internal antipodal transition of the cell, according to embodiments of the invention.

[0024] [Fig.6] [Fig.6] is a perspective view of a cell of the control device of radio frequency beams showing the support frame and internal planar elements of the cell, according to embodiments of the invention.

[0025] [Fig.7a] and [Fig.7b] Figures 7a and 7b are sets of graphs illustrating the radioelectric performances achieved by a radiofrequency beam control device according to exemplary embodiments of the invention.

[0026] [Fig.8] [Fig.8] is a set of graphs illustrating the performance radioelectric frequencies achieved by a radiofrequency beam control device, according to exemplary embodiments of the invention.

[0027] Identical references are used in the figures to designate identical or similar elements. For reasons of clarity, the elements shown are not to scale. Detailed description

[0028] [Fig.l] schematically represents a radiofrequency (RF) beam control device 10 according to embodiments of the invention.

[0029] The RF beam control device 10 (also referred to as 'device 10' hereinafter) may be used in an antenna system 1. For example and without limitation, an antenna system may be implemented in the form of an active antenna mounted on board a satellite in low Earth orbit (or LEO for Low Earth Orbit according to the English name) and belonging to a constellation of satellites intended to provide telecommunications services across the Earth.

[0030] An antenna system 1 can thus be configured to transmit and / or receive beams (or signals) of RF electromagnetic waves. An RF electromagnetic wave beam is associated with an RF frequency band (being inversely proportional to a wavelength A). For example, an antenna system 1 can be configured to transmit an RF signal in specific frequency bands. Such a specific frequency band can correspond to a low frequency band, such as for example an “L band” or an “S band” typically between 1 and 2 GHz or 2 and 4 GHz. Such a specific frequency band can also correspond to a higher frequency band (used for high-speed telecommunication systems for example), such as for example a “Ku band”, a “Ka band” or a “Q / V band” typically between 12 and 18 GHz or 22.5 and 40 GHz.An electromagnetic wave of an RF signal can be further characterized by a given phase, a given amplitude and a given polarization. The RF beams emitted by the antenna system 1 are designated by the notation SRF10 in Figures 1 and 2, and the RF beams received by the antenna system 1 are designated by the notation SRF20 in Figures 1 and 2.

[0031] The radio frequency beam control device 10 may be configured to transmit the SRF10 beams. In addition, the radio frequency beam control device 10 may also be configured to receive external SRF20 beams. Thus, as used herein, the term “radio frequency beam control” (also called “radio frequency beam manipulation”) refers to various phenomena related to electromagnetic waves that may occur when an RF beam interacts with the material of a given object (here the device 10). These phenomena may include in particular the emission, reception, transmission, reflection, absorption, diffusion, refraction and / or diffraction of the electromagnetic wave.

[0032] As shown in [Fig.l], the RF beam control device 10 is defined in a frame (X,Y,Z). In particular, the device 10 comprises a first face 11 (also called 'input face') and a second face 12 (also called 'output face') opposite the first face 11. The beam SRF10 is emitted from the second face 12 of the device 10 while the beam SRF20 is received by the second face 12. The terms "input" or "output" are used herein depending on the direction of circulation of the radiofrequency (RF) waves in the device 10 when it operates in transmission, that is to say according to the direction of circulation going from the first face 11 to the second face 12.

[0033] The two faces 11 and 12 are spaced apart from each other by a distance dz representing the thickness of the device 10. The thickness value of the device dz is very small compared to the overall size of the antenna system, the device 10 can have a generally planar structure, defined in the plane (X,Y) orthogonal to the axis Z. Thus, the device 10 generally extends in the plane (X,Y).

[0034] In one embodiment, the two faces 11 and 12 of the device 10 may be parallel to each other. In such an embodiment, the two faces 11 and 12 may be surfaces defined in two dimensions in the plane (X,Y) orthogonal to the normal axis Z. Alternatively, the two faces 11 and 12 may be surfaces defined in three dimensions in the reference frame (X,Y,Z). In these embodiments, the thickness of the device dz between the two parallel faces 11 and 12 is homogeneous along the device 10.

[0035] Alternatively, the thickness of the device dz between the two faces 11 and 12 is inhomogeneous along the device 10, the thickness of the device d2 varying along the X axis and / or along the Y axis. In this embodiment with variable thickness of the device, at least one of the two faces 11 and 12 can be defined as a surface defined in three dimensions in the (X,Y,Z) frame of reference. For example and in a non-limiting manner, the device 10 can comprise a center O positioned in the (X,Y) plane, the thickness of the device dz varying in an increasing or decreasing manner from this center O along the X axis to form a quasi-optical element, which can be a concave or convex element.

[0036] The RF beam control device 10 according to the embodiments of the invention comprises a set of cells 100 arranged in the (X,Y) plane, as shown in [Fig.l].

[0037] An SRF10 beam emitted by the device 10 can be characterized by a given emission incidence direction. As shown in FIG. 1, the emission incidence direction of an SRF10 beam forms with the normal axis Z of the device 10 an emission incidence angle noted 0e.

[0038] An SRF20 beam received by the device 10 can be characterized by a given reception incidence direction. As shown in FIG. 1, the reception incidence direction of an SRF20 beam forms with the normal axis Z of the device 10 a reception incidence angle noted 0r.

[0039] The SRF10 beams emitted and / or SRF20 received by the device 10 may also be characterized by a maximum angular sector 6max, the angles of incidence of emission 0e and reception Qr then being between 0 and 0max. The SRF10 beams emitted and / or SRF20 received are then described as 'off-target'. For example and without limitation, the maximum angular sector noted may be equal to ±55°. The emitted SRF10 and / or received SRF20 beams can also be associated with an angular sector of vision noted and corresponding to an angular sector where the beam transmission must be carried out, i.e. an angular sector without “blinding”.

[0040] In the exemplary embodiment shown schematically in [Fig.2], the antenna system 1 comprises the RF beam control device 10 and a beam forming unit 20.

[0041] The beam forming unit 20 (also referred to more simply as 'unit 20' in the remainder of the description) may be a multi-beam former as described for example in patent application FR2986377A1.

[0042] The beamforming unit 20 may be configured to generate and transmit to the device 10 one or more electromagnetic wave signals, designated by the notation SRF12 in [Fig. 2]. Advantageously, the beamforming unit 20 may be configured to transmit to each cell 100 of the device 10 a distinct SRF12 signal.

[0043] In certain embodiments of the invention, the unit 20 can be configured to apply to these SRF12 signals a modification of the phase and / or the amplitude, so as to defocus the SRF10 beams emitted according to emission incidence angles A „ distinct and / or variable between 0 and 0 LIIcla.

[0044] In these embodiments, the unit 20 can therefore be configured to receive one or more RF SRF22 signals from the transmission of the external SRF20 beam received by the device 10. Thus, the unit 20 can be configured to receive from each cell 100 a distinct SRF22 signal to be processed. The unit 20 can be configured to apply to these SRF22 signals a measurement of the phase and / or the amplitude so as to estimate the reception incidence direction of the received SRF20 beam. The unit 20 can also be configured to apply a weighted combination of the RF SRF22 signals as a function of the estimated direction. Advantageously, the antenna system 1 can comprise a processing unit (for example a processor of the payload of the satellite not shown in the figures) configured to process the SRF22 signals received and processed by the unit 20.

[0045] Each cell 100 of the device 10 corresponds to a radiating element and comprises an external cell support frame 130 and an internal cell excitation element 150. The device 10 is thus referred to as a 'radiating panel'.

[0046] [Fig. 3] shows only the support frame 130, to facilitate understanding of the invention. Figures 4, 5 and 6 illustrate perspective views of a cell 100 comprising a support frame 130, according to different embodiments.

[0047] The support frame 130 of a cell 100 is inscribed in a generally tubular shape having a main axis extending along the Z axis, also called the “frame axis”.

[0048] As shown in Figure 3, the support frame 130 of a cell 100 (also called waveguide) comprises a frame inlet 131, arranged in the (X,Y) plane, at the input face 11. The position Zq of the frame inlet 131 along the Z axis is called the “inlet position”. The support frame 130 of a cell 100 further comprises a frame outlet 132, aligned in the (X,Y) plane at the output face 12. The position Zc of the frame outlet 132 along the Z axis is called the “outlet position”.

[0049] The support frame 130 is made up of a set of "walls" having a wall thickness m. The support frame 130 has a frame length defined along the frame axis Z. The support frame length may be substantially equal to the device thickness dz, such that dz - Zc- Zq. For example and without limitation, the device thickness dz may be less than or equal to a value substantially equal to 2 / 2. In embodiments where the device thickness dz is variable in the (X,Y) plane, each cell 100 may be associated with a specific cell length d^ny

[0050] The tubular shape of the support frame 130 comprises a cross-section defined in a plane (X,Y) perpendicular to the Z axis. The cross-section is characterized by a given shape and a perimeter value P calculated as a function of the dimensions of the shape of the cross-section. For example and without limitation, the cross-section may be circular, oval, square, rectangular, or polygonal.

[0051] In certain embodiments where the cross-section is a polygon comprising a number N c of sides, the tubular shape may correspond to a polyhedron with N c facets each having a parallelogram shape. Each facet (or “prismatic face” corresponding to the walls) extends along the axis of the frame Z. Such a polyhedron may be, for example, a regular polygon of even order, and in particular a square parallelepiped polygon (where N c = 4), called a cuboid, or a hexagonal prism (where N c = 6), as shown in FIG. 3. In such an embodiment, the N c facets are connected to each other by N c edges oriented along the axis of the frame Z.

[0052] The support frame 130 of a cell 100 also comprises a number N of slots (or notches) denoted 133-n, "n" being an index associated with the different slots, with H € [ 1, N ]. Each slot 133-n extends along the axis of the frame Z, from the frame exit position Zc 132 to a slot position (or initial slot position) denoted Xon- As shown in FIG. 3, the slot position Zqu is arranged between the frame entrance 131 (i.e. entry position Zq) and the frame exit 132 (i.e. exit position Zc). Thus, each slot 133-n has a slot length dn defined according to the axis of the frame Z, such that dn = Zc- Zqs and dn < dz (or du < d^). Each slot 133-n is further associated with at least two slot edges, denoted respectively ni and n2, representing the limits of the support frame 130 and connecting the slot position Zqu to the output position Zc as shown in Figure 3. Each slot edge, ni or n2, can be characterized by a predefined so-called variability function, denoted respectively f or As a result, each slot 133-n has a variable slot width, along the axis of the frame Z, constructed from the variability functions ^nlct

[0053] In particular, the slots may be flared towards the exit position 132. Thus, the variable slot width takes a maximum slot value co“iax at the exit of the support frame 132 and a minimum slot value at the position The maximum slot value may be determined as a function of the perimeter P of the cross-section of the cell 100 and the number N of slots 133-n. The minimum slot value is less than the maximum slot value 0)“iax, i.e.:

[0054]

[0055] For example and without limitation, a slot variability function fn may be a linear function (see FIG. 5), a staircase function or any other function (monotonic or not, increasing polygonal called concave and / or convex as illustrated in FIGS. 3, 4 and 6 for example) so as to vary the width of the slot 133-n along the axis of the frame Z from a minimum value to a maximum value. Advantageously, a slot variability function fn may be defined by an exponential function so as to vary the width exponentially between the minimum value (ogïm to the maximum value to™^.

[0056] In some embodiments, the edges of slots n1 and n2 of a slot 133-n may be symmetrical to each other with respect to a Z axis defined at the center of this slot 133-n. In particular, in embodiments where the slot 133-n is positioned on a facet of the support frame 130, the edges of slots n1 and n2 may be symmetrical with respect to a Z axis defined at the center of this facet.

[0057] The dimensions of the slits (i.e. the widths and variabilities and / or the lengths of slits dn for example) of the same cell 100 and / or of the slits of all the cells 100 of the RF beam control device 10 may be identical or different from each other depending on the applications of the invention. For example, and in a non-limiting manner, an RF beam control device 10 may comprise modulations of the profile of slits 133-n (of a few micrometers for example) relative to the center O of the device 10 in order to spatially modulate the phase of the incident beam, so as to treat certain edge effects. Thus, the RF beam control device 10, generally extending in an (X,Y) plane, may comprise an array of several cells 100 having geometric shapes and varying support frame and slot dimensions in the (X,Y) plane chosen so as to very finely modify (at the cell scale) the phase and associated wavefront of the electromagnetic wave in the (X,Y) plane.

[0058] In the embodiments where the slot lengths dn of the slots of the same cell 100 are identical, the support frame 130 of this cell 100 can be broken down into two parts, shown in [Fig.3], comprising: - A first part of length dQn (or d0) corresponding to a support frame 130 without slot, and

[0059] - A second part of length dn (or d) corresponding to a support frame 130 with slots.

[0060] According to certain embodiments, the length of the first part dQn of a slot 133-n (such that dQD = ZQn- Zc) may be equal to the wall thickness m. For example, the first part without a slot may be negligible compared to the second part with slots in the case where all the slots of the same cell 100 are characterized by the same length d()n of the first part then equal to the wall thickness m, such that Zqu = Zq, as shown in [Fig.6].

[0061] The minimum value of the width of a slot 133-n may be equal to 0, i.e. (0min = 0 and < m. as shown in Figures 5 and 6. Alternatively, the minimum slot value may be greater than or equal to the wall thickness as shown in Figures 3 and 4. Such a minimum slot value OJpim other than zero makes it possible to obtain a compact cell design 100 along the Z axis.

[0062] The maximum value of the width of a slot 133-n is greater than the wall thickness. In particular, the maximum slot value can be defined as a function of the ratio between the perimeter P of the cross-section, the number N of slots 133-n, and a proportion coefficient noted £n, as defined by the following expression (02):

[0063] wmax = £jiX ? (02)

[0064] In particular, the sum of the proportion coefficients £n on all the slots 133-n is less than or equal to N, according to the following expression (03):

[0065] 2n£n <m

[0066] In embodiments, the maximum values ​​0J°iax of width of the slots of the same cell 100 may be identical.

[0067]

[0068]

[0069]

[0070]

[0071] In particular, the proportion coefficients En can be equal for the N 130-n slots of a cell. For example and without limitation, the width parameters £n = £ can be equal to 1, with g = j\f, as shown in Figures 3, 4 and 6, while the maximum values ​​a)^1^ of slit width 133-n are defined according to the following equation (04): œmax=coniax= £ (04) Alternatively, the width parameters may be less than 1, with ^£< N, as shown in Figure 5 where £ = 2' while the maximum values ​​of slit width 133-n are equal to 0Jmax = P / 4. In embodiments where the cross-section is a regular polygon, a 133-n slot can be positioned on one of the facets of the polyhedron of width Jc = X. The maximum value 0)§iax of width of a slot can be for example defined according to the following equation (05): ^<^(05)

[0072] In some embodiments where the cross-section is a regular polygon, a slot 133-n may be positioned so that it coincides with an edge of the polyhedron.

[0073] The number N of slots 133-n can be equal to the number Nc of sides, as shown in Figures 3, 4 and 6.

[0074] Alternatively, the number N of slots 133-n may be less than the number Nc of sides, as shown in FIG. 5. In particular, in embodiments where the cross-section is a square and where the electromagnetic field of the RF signal circulating in the waveguide 130 comprises a given linear polarization defined along an axis X' defined in the plane (X,Y), the number N of slots 133-n may be equal to 2 and each slot 133-n may be positioned on a facet of the polyhedron parallel to the polarization axis X' (i.e. the slots then being arranged parallel to the electric field of the electromagnetic wave of the RF signal circulating in the waveguide 130).

[0075] Alternatively, the number N of slots 133-n may be greater than the number Nc of sides (not shown in the figures). For example and without limitation, a facet of the polyhedron may comprise at least two slots 133-n. In particular, in these embodiments, the slots 133-n positioned on the same facet of support frame 130 may be symmetrical with respect to an axis Z defined at the center of this facet.

[0076] Advantageously, in the embodiments where the thickness of the device d^ is variable in the plane (X,Y), the dimensions associated with the longitudinal slots 133-n (in particular, different lengths of slots dn of the same support frame 130) are adapted to compensate for this variability in thickness d^, allowing the adjustment of the slots 133-n to the variability of the wall lengths between adjacent cells.

[0077] Furthermore, the support frame 130 may be entirely or partially metallic so as to form an electrically conductive structure. The notched opening of the support frames 132 at the N slots 133-n makes it possible to simulate a partially dielectric material and to significantly broaden the transmission band of the RF beam control device 10.

[0078] The support frame 130 of a cell 100 is further characterized by an impedance. In particular, the dimensions associated with the longitudinal slots 133-n make it possible to adjust the characteristic impedance of the cell 100. The variability of the width æa of the longitudinal slots 133-n, and in particular a variability function defined by an increasing or exponential function, makes it possible to progressively modify the impedance of the second frame part with slots, from an input impedance of the waveguide (following the impedance of a first frame part without slot, typically a hundred ohms) up to an adaptation of the impedance of the free space (i.e. to 377). This progressive modification of the impedance of the support frame 130 (and therefore of the device 10) makes it possible in particular to stabilize the active impedance of the radiating elements of the device 10 in an antenna system regardless of the depointing angle of the incident beam.

[0079] Therefore, a support frame 130, metallic and notched by the N longitudinal slots 133-n (or slotted), acts as a waveguide allowing the propagation of electromagnetic waves in TEM mode to be transmitted by the RF beam control device 10. Such support frames 130 can thus function as radiating elements in all frequency bands of the RF signals, and can be used in particular for L, S, C, Ku, Ka and Q / V bands. Indeed, the longitudinal slots allow the electric fields not to completely cancel each other out on the sides of the waveguide, which allows the electromagnetic waves in TEM mode to settle.

[0080] The set of cells 100 forms a periodic arrangement of waveguides (or a network of cells 100) whose dimensioning is small compared to the wavelength 2 associated with the frequency band of the emitted or received RF beam (SRF10 and SRF20). The electric field excited in a waveguide then couples to the neighboring waveguides, inducing a significant coupling between cells, which makes it possible to propagate the electromagnetic waves in mode over a wide frequency band, and to ensure a strong mutual coupling with between adjacent guides. Such a set of cells 100 forms a wideband transmission window making it possible not to introduce frequency dispersion into the sections of the waveguide.

[0081] The different cells 100 of the device 10 are adjacent and connected to each other, along the frame axis Z, by common cell parts. For example and without limitation, for a polygonal cell cross-section, the different cells 100 may be connected by the prismatic faces.

[0082] The periodic arrangement of cells can be characterized by a mesh size of the network noted (p defined from the shape and dimensions associated with the transverse sections of the cells 100.

[0083] In an embodiment in which the cross-section of the cells 100 is circular in shape, the mesh size 0 corresponds to the diameter of the circular section. In an embodiment in which the cross-section of the cells 100 is polygonal in shape, the mesh of the network (p corresponds for example to the diameter of the circle circumscribed to the polygonal section or to the width lc of the side of the polygon.

[0084] Advantageously, the mesh of the network (p) of the device 10 can be uniform or variable in the plane (X,Y) depending on the modes of application of the invention. In particular, the mesh of the network (p) can be determined with respect to a maximum mesh value noted (p). The maximum mesh value d) can be defined ^max ^max r depending on the wavelength Z of the emitted or received RF beam (SRF10 and SRF20), the maximum angular sector of misalignment ± 0max and the angular sector of vision ± The maximum mesh value 0max can be defined for example according to the following expression (06):

[0085] A = 2 (06) ^max sin^jR-siiXjeJ)

[0086] For example, the mesh of the network 0 may be less than the maximum mesh value (pm^v such that (p < (p„^v. In this embodiment, the mesh of the network (p makes it possible not to cause the appearance of network lobes generated by a periodicity effect associated with the mesh. In addition, the mesh of the network (p may be determined so as to minimize the number of radiating elements in the RF beam control device 10. Advantageously, the mesh of the network (p may be between 0.4 A and 0.6 A. In particular, in the embodiments where the beams SRF10 and / or SRF20 are so-called dual-band signals, i.e. comprising two distinct RF frequency bands, the mesh of the network (p may be equal to 0.4.

[0087] Furthermore, the thickness of common walls between two cells 100 can be defined as being equal to a value 2 x m. The thickness 111 of the support frame 132 can be small and can also be adjusted, for example minimized, so as to attenuate the transmission losses of the SRF10 and / or SRF20 beams at the interfaces between the air and the waveguide (for example at the input of frame 131 and / or at the output of frame 132). It should be noted that the transmission losses on a frequency band and a sector angular are proportional to the ratio m / 0- The reduction of the bandwidth and the reduction of the angular sector associated with the RF wave can be correlated to the quantity of metallic material forming the support frame 130. The minimization of the wall thickness 111 can furthermore lead to a minimization of the total mass of the device 10, while guaranteeing its rigidity. Advantageously, the wall thickness m is less than the wavelength 2, which makes it possible to confer stability of transmission of the RF wave with respect to the variation of the angle of incidence (in particular reception 6r) on the device 10. In particular, the wall thickness m according to the modes of the invention can be between 250pm and 500jjm. The wall thickness m can further be defined according to the advantages and constraints associated with the manufacturing process of the device 10.For example and without limitation, when the device is manufactured using an additive manufacturing process (or 3D printing technique), the thickness of walls between two cells 100 of an RF beam control device 300 may be equal to a value 2 X m = 500jtzm. When the device is manufactured using a so-called traditional manufacturing process, the thickness of walls between two cells 100 may be equal to a value 2 X m — 1mm, .

[0088] In certain embodiments, the frame entrance 131 may be "closed" (or "sealed") in the (X,Y) plane by a closing wall 11-0 (not shown in FIG. 3 but illustrated in FIG. 6). Advantageously, the thickness of this closing wall 11-0 may be equal to the wall thickness ni. In particular, each support frame 130 may comprise a frame entrance 131 closed along the entrance face 11 of the device 10. A device 10 comprising closing walls 11-0 of the frame entrance 131 of the cells has manufacturing and structural strength advantages. This closing wall 11-0 may be metallic.

[0089] In the embodiments where the cross-section of the cells 100 of the device 10 is polygonal, the different cells 100 being adjacent and connected to each other by the prismatic faces, the set of closing walls 11-0 of the frame entrance 131 of the cells can form a single entrance plate. This entrance plate corresponds to a ground plane of the device 10.

[0090] For a device 10 comprising cells 100 of polygonal cross-section comprising a number of sides Nc < 4, the device 10 may have manufacturing advantages since the overall structure has less material. Alternatively, for a device 10 comprising cells 100 of circular or polygonal cross-section defined according to Nc > 4, the device 10 may have better impedance properties (in the active input part) of the radiating elements compared to to the variation of the opening angle (i.e. the angular orientation) of the SRF10 and / or SRF20 beams at the interfaces between the air and the waveguide.

[0091] Each cell 100 of the RF beam control device 10 comprises an internal excitation element 150 of the cell 100 as shown in FIGS. 4, 5 and 6. The implementation of an internal excitation element 150 in the support frame 130 makes it possible to preserve the intrinsic broadband properties of the waveguide. In particular, the implementation of an internal excitation element 150 in the support frame 130 allows the progressive conversion of the fundamental mode of the RF signal circulating in the waveguide to the TEM mode of the RF signal which propagates in the slotted sections.

[0092] According to certain embodiments, an excitation element 150 may comprise a number H of longitudinal metal structures 152-h extending along the axis of the frame Z and arranged inside the cell 100. "h" is an index associated with the different slots, with h € [ 1, H ]. Each metal structure 152-h, also called a "rib", is connected to the support frame 130 by a rib edge h0 defined, along the axis of the frame Z, extending from the frame entrance 131 (i.e. entrance position Zq) to a rib position denoted ZjT As shown in the perspective view of a cell of FIG. 4, the rib position Z^ is arranged between the frame entrance 131 (i.e. entrance position Zq) and the frame exit 132 (i.e. exit position Zc). Thus, each 152-rib has a rib length dh along the frame axis Z, such that d^ = Z^- Zq and d^ < dz (or dh < d^ÿ).

[0093] The distribution of all the ribs inside the support frame 130 can be determined as a function of the perimeter P of the cross-section of the cell 100 and the number H of ribs 152-h.

[0094] In the embodiment where the cross-section of the cell 100 is a polygonal cross-section, a rib 152-h may be arranged inside the frame at an edge of the polyhedron forming the cell and oriented along the axis of the frame Z. The number H of ribs in a cell may further be defined as a function of the number N of slots 133-n and / or the number Nc of sides of the polygonal cross-section of a cell 100. For example and without limitation, the number H of ribs 152-h may be equal to the number N of slots 133-n. All of the ribs may be regularly distributed around the waveguide according to a regular spacing between the ribs, for example equal to the ratio of the perimeter P to the number H.As shown in the example of Figure 4, each rib 152-h can be positioned at each edge of the polyhedron forming the cell (such that Z = j^), while each slot 133-n can be positioned on one side of the cell 100. In a . Alternatively, each rib 152-h may be positioned at an interior side surface of the cell 100.

[0095] In particular, in the embodiments where the electromagnetic wave of the RF signal circulating in the waveguide 130 comprises a given linear polarization defined along an axis X' defined in the plane (X,Y), each rib 152-h can be positioned in a plane orthogonal to the slots 133-n of the cell 100, the slots then being arranged parallel to the electric field of the electromagnetic wave of the RF signal circulating in the waveguide 130.

[0096] In embodiments, the rib position Z^ along the frame axis Z may be arranged between the frame entrance 131 (i.e. entrance position Zq) and a slot position Zqü, such that the rib 152-h is located in a first portion of length dOn corresponding to the support frame 130 without a slot with d^ < dOn. Alternatively, the rib position Z^ may be arranged between the frame exit 132 (i.e. exit position Zc) and a position Zqb of a slot 133-n, such that d^ > In this case, a portion of the rib 152-h and a portion of the slot 133-n may overlap (or be "superimposed") at least partially over an overlap distance between Z^ and Zq1y. A cell 100 comprising a superposition between ribs and slots allows to ensure a progressive conversion of the fundamental mode of the RF signal circulating in the waveguide (ribbed guide in this case) to the TEM mode of the RF signal which propagates in the slotted sections (slot guide). Such a superposition between ribs and slots also allows to obtain a compact 100 cell design.

[0097] Furthermore, each rib 152-has a thickness and a width 1^. The rib thickness and / or the rib width 1^ are variable dimensions along the axis Z such that each rib 152-h comprises a plurality of “steps” distributed along the along the Z frame axis.

[0098] In certain embodiments, the rib thickness and / or the rib width takes a maximum value (respectively ZH^1^ and at the entrance of frame 131 (i.e. input position Zq), and a minimum value (respectively and imin) the position of rib Zjr The number of steps and their dimensions can be determined as a function of the rib length d^ and maximum and minimum rib values ​​j™, ZD}™11 and J™in), according to a variability profile of rib noted f Advantageously, the minimum value of the rib thickness 2Xjniin and / or of the rib width can be equal to the wall thickness

[0099] The different dimensions of the rib 152-h are configured to contribute to the conversion of modes in the waveguide of the cell 100. In general, the thicknesses and heights of the steps of the ribs 152-h can in particular vary in a decreasing manner along the Z axis, from the input position Zq to the rib position Zlr.

[0100] Advantageously, the dimensions of the ribs of the same cell 100 and / or of the slots of all the cells 100 of the RF beam control device 10 may be identical or different from each other depending on the modes of application of the invention.

[0101] In the absence of these 152-h rib elements, and with a weak 0 network mesh (between 0.4 2 and 0.6 2), it is no longer possible to propagate a mode over a wide RF band to excite the radiating element.

[0102] In embodiments, a support frame 130 associated with ribs 152-h may comprise a polarizer (or so-called 'septum' polarizer and not shown in the figures) for generating double circularly polarized radiation. As used herein, a "polarizer" refers to an element intended to convert, on the one hand, the received SRF20 signals having a circular polarization into SRF22 signals having a linear polarization and, on the other hand, the SRF12 signals to be transmitted having a linear polarization into SRF10 signals having a circular polarization. The polarizer may be formed by an internal blade extending along the axis of the Z frame and generated from two ribs 152-h connected at least in part to each other inside the cell 100.For example, the two 152-h ribs connected to form the polarizer may arise from opposite edges of the polygonal right cylinder or from two opposite inner side surfaces of the polygonal right cylinder.

[0103] Figures 7(a), 7(b) and 8 are graphs illustrating examples of radio performance achieved by a device 10 comprising an excitation element 150.

[0104] In particular, the graphs of Figure 7(a) show the evolution of the simulated active reflection coefficient as a function of the frequency for a device 10 of which each cell 100 comprises ribs 152-h, according to embodiments of the invention. The determination by simulation of the active reflection coefficient makes it possible in particular to characterize the variation of the active impedance of the device 10, by taking into account a radiating element surrounded by an infinity of similar radiating elements (i.e. infinite network) associated with a phase gradient of an electromagnetic wave. The phase gradient makes it possible to orient the beam resulting in emission of the device 10 according to a given angle of incidence 0. The graphs of Figure 7(a) highlight a stabilization of the active impedance over a large angular sector. Indeed, the active reflection coefficient shown in Figure 7(a) is less than -10 dB for a wide band of Ka and X frequencies of electromagnetic background whatever the direction of propagation of the emission beam (i.e. according to the spherical coordinates 0, with phi = 0 0 and phi = 60 0 ).

[0105] The graphs of Figure 7(b) show the evolution of the simulated gain of an electromagnetic wave in a continuity of given emission directions 9 (or phi) of the beam resulting in emission, in co-polarization and cross-polarization of the RF source, for a device 10 of which each cell 100 comprises ribs 152-h, according to embodiments of the invention. The determination by simulation of such a radiation pattern on a given angular sector can be correlated to the variation of the active impedance on this angular sector of a radiating element powered by an electromagnetic wave and positioned at the center of a small network (for example at the center of 24 other similar radiating elements and connected to a load), thus taking into account the mutual coupling between the radiating elements as well as the edge effects associated with this small network.The graphs in Figure 7(b) highlight a stabilization of the radiation pattern in all the emission planes of the device 10, as well as a small decrease in cross-polarization gain ranging from 3 to 5 dB. Indeed, the variation in the main polarization gain of this so-called “surrounded” radiation pattern (i.e. graphs in Figure 7(b)) is linked to the variation in the active impedance as a function of the direction of the beam. Thus, the more stable the gain is over a set of beam incidence directions, the lower the degradation of the active impedance is when a beam is pointed in these directions.

[0106] The transmission mode of the microwave waves in the amplifiers and in the radiating panel 10 are different. Indeed, the waves at the output of the radiating panel are transmitted via a waveguide (ridged) while the waves in the amplifier are generally propagated using a line called a “microstrip line” or “microstrip line” which can be any type of suitable microwave transmission line. The transition from the propagation mode of the HF waves in a waveguide from the radiating panel to the microstrip line of the amplifiers is achieved via a suitable transition.

[0107] According to certain embodiments, an excitation element 150 may comprise an antipodal transition called “Vivaldi” 154 arranged inside the cell 100, making it possible to make a transition between a waveguide and a microstrip line.

[0108] As shown in the perspective view of a cell of [Fig.5], an antipodal transition 154 comprises a first metal structure 154-1 extending in a first plane (X',Z), and a second metal structure 154-2 extending in a second plane (X',Z) parallel to the first plane (X',Z).

[0109] According to some embodiments, the antipodal transition 154 may be a “tri-planar structure” (or “tri-plate line”) such that the antipodal transition 154 comprises a third metal structure 154-3 extending in a third plane (X',Z) parallel to the first and second planes (X',Z). In particular, the first metal structure 154-1 may be disposed between the second metal structure 154-2 and the third metal structure 154-3. In this case, the third metal structure 154-3 has a shape equivalent to the second metal structure 154-2.

[0110] In embodiments, an antipodal transition 154 may further comprise a dielectric substrate 154-0 comprising at least a first dielectric face and a second dielectric face, the second dielectric face being opposite and parallel to the first dielectric face, the first and second dielectric faces extending along the Z-frame axis. In these embodiments, the first metal structure 154-1 corresponds to a first metal etch 154-1 disposed on the first dielectric face, and the second metal structure 154-2 corresponds to a second metal etch 154-2 disposed on the second dielectric face. In embodiments where the antipodal transition 154 is a "tri-planar structure", the dielectric substrate 154-0 may comprise a third dielectric face extending along the Z-frame axis and parallel to the first and second dielectric faces.In particular, the first dielectric face may be arranged between the second and third faces of the dielectric substrate 154-0. In this case, the third metal structure 154-3 corresponds to a third metal etching 154-3 arranged on the third dielectric face and having a shape equivalent to the second metal etching 154-2.

[0111] In some embodiments, the dielectric substrate 154-0 may be positioned inside the support frame 130 and connected by one or two opposite edges or by two opposite inner side surfaces of the support frame 130, by a substrate edge, and / or a first and a second substrate edge denoted g0-l or g0-2, of substrate length dg and defined along the axis of the frame Z, from the frame entrance 131 (i.e. entrance position Zq) to a substrate position denoted Zg, such that dg = Zg - Zq and that dg < dz (or dg < d^^).

[0112] In embodiments, the substrate position Zg along the frame axis Z may be arranged between the frame entrance 131 and a slot position Zqw such that the dielectric substrate 154-0 is located in a first portion of length dGü corresponding to the support frame 130 without a slot with dg < dQir Alternatively, the substrate position Zg may be arranged between the frame exit 132 (i.e. exit position Zj and a position Zqu of a slot 133-n, such that dg > d§n. In this case, a portion of the dielectric substrate 154-0 and a portion of the slot 133-n may be overlap (or be “superimposed”) over an overlap distance between Z g ct ^On-

[0113] Furthermore, the first metal structure (or etching) 154-1 may form a conductive microstrip arranged at the frame input 131 (i.e. input position Zq). The first metal structure (or etching) 154-1 is progressively widened in the first plane (X',Z), inside the waveguide up to a first etching position Zgg so as to be connected to a first substrate edge gO-1.The second metal structure (or etching) 154-2 (and optionally the third metal structure or etching 154-3) may form a ground plane from a position Zm lower than the entry position Zq of the frame entry 131 to a second etching position Zmg- The second metal structure (or etching) 154-2 (and optionally the third metal structure or etching 154-3) may also form a progressively widened conductive microstrip in the second plane (X',Z), inside the waveguide from the second etching position Zmg to the first etching position Zg so as to be connected to the second substrate edge gO-2.It should be noted that the electric field is then established between the first metal structure (or etching) 154-1 and the second metal structure (or etching) 154-2 (and possibly between the first metal structure or etching 154-1 and the third metal structure or etching 154-3) along the polarization axis X' shown in [Fig.5].

[0114] Advantageously, the first etching position Z^g. along the axis of the frame Z, is arranged between the frame entrance 131 and the substrate position Z g, and the second etching position Zmg. along the axis of the frame Z, is arranged between the frame entrance 131 and the first etching position Z^g.

[0115] In embodiments where the substrate position Z g is arranged between the frame exit 132 and a position ZQn of a slot 133-n, the first etching position Zç)g along the axis of the frame Z may be arranged between the substrate position Z g and the position ZOn of the slot 133-n. In this case, a portion of the first and second metal etches and a portion of the slot 133-n may overlap (or be "superimposed") at least partially over an overlap distance comprised between Z g and Zq]Y

[0116] In embodiments, the metal structures (or etchings) 154-1, 154-2 (and possibly 154-3) may be characterized by a thickness ms defined in a plane perpendicular to the planes (X',Z). In particular, the thickness ms of each metal structure (or etching) may be equal to the wall thickness m.

[0117] Advantageously, the shape of each metal etching of the antipodal transition 154 is configured to “rotate” the electric field.

[0118] According to certain embodiments, an excitation element 150 may comprise a number T of planar metallic elements 156-t extending in the plane (X,Y) and arranged one above the other along the axis of the frame Z. "t" is an index associated with the different slots, with t G [ 1, T]. Advantageously, in such embodiments, the excitation element 150 further comprises a closing wall 11-0 arranged at the frame entrance 131 of the cell (and by extension the entrance face 11 of the device 10).

[0119] In particular, each planar element 156-t (also called a planar radiating element or 'patch') may be of any shape. For example and without limitation, a planar element 156-t may be of a circular shape or a polygonal shape comprising a number N c of sides. A planar element 156-t may further be centered within the support frame 130. Each planar element 156-t may be arranged at a planar position Zt defined between the frame entrance 131 (i.e., entrance position Zq) and the frame exit 132 (i.e., exit position Zq), as shown in [Fig. 6].

[0120] In embodiments, a planar position Zt defined along the frame axis Z may be located between the frame entrance 131 (i.e., entrance position Zq) and a slot position Zqw such that a planar element 156-t is located in a first portion of length dGn corresponding to the support frame 130 without a slot with d^ < dQn. Alternatively, a planar position Zt may be located between the frame exit 132 (i.e., exit position Zc) and a position ZQn of a slot 133-n, such that d^ > dQn. In this case, the planar element 156-t may be located above the position Z$n of slot 133-n at the position Zt. A cell 100 comprising at least one planar element 156-t located above the base of the set of slots (i.e. position Zq^) makes it possible to obtain a compact cell design.

[0121] Furthermore, each planar element 156-t may be separated by a spacing dz between the closing wall 11-0 and / or one of the other planar elements 156-t. Each planar element 156-t may be characterized by a thickness and a width Dt. In particular, the thickness of each planar element 156-t may be equal to the wall thickness m.

[0122] Advantageously, the planar elements 156-t may be connected to each other and / or to the closing wall 11-0 by one or more substrates 156-0, extending along the axis of the frame Z inside the support frame 130. For example and without limitation, a substrate 156-0 of a planar element 156-t may be metallic so as to form an all-metal cell 100. Alternatively, a substrate 156-0 of a planar element 156-t may be dielectric.

[0123] The electromagnetic coupling between several patches of different dimensions produces additional resonances which make it possible to increase the bandwidth, as illustrated in the graphs of figure 8 showing the evolution of the simulated active reflection coefficient as a function of the frequency, for a device 10 whose cells 100 comprise planar elements 156-t according to embodiments of the invention, as a function of different emission beam directions (ie e=25° and e=50°).

[0124] In embodiments, a planar element 156-t may comprise a number Tx of cavities 156-tx which notably makes it possible to modify the resonance frequency of the cell 100. The arrangement of cavities 156-tx on the planar element 156-t of the cell 100 also makes it possible to reduce the mass of the planar element 156-t.

[0125] The different dimensions of the planar elements of the same cell 100 and / or of the planar elements of all the cells 100 of the RF beam control device 10 may be identical or different from each other depending on the applications of the invention. For example and without limitation, the width Dt of the planar elements may be progressively reduced between the width of a planar element at the output of the cell 100 compared to the width of a planar element at the input of the cell 100. This reduction in width Dt of planar elements makes it possible to contribute to the progressive adaptation of the impedance of the cell with the impedance of the free space.

[0126] The embodiments where the excitation element 150 comprises planar metallic elements are particularly suitable for use for radiating elements in low frequency bands L or S. Furthermore, these embodiments allow the design of a compact device, with reduced vertical size, in particular along the Z axis, and low mass, which is beneficial for antenna applications on satellites.

[0127] The RF beam control device 10 may be manufactured using various techniques. One manufacturing technique may be a 3D printing technique, also known as additive manufacturing. Some 3D printing techniques make it possible to obtain a uniform device 10, which does not include a dielectric and is entirely metallic, by using an electrically conductive material such as aluminum or titanium, for example. The electrically conductive material such as titanium may then be covered with another electrically conductive material such as silver, for example, in order to reduce ohmic losses. These 3D printing techniques are particularly suitable for use of the device 10 in Ku, Ka, and Q / V. A technique for manufacturing patches relating to use of the device 10 in low frequency bands L or S, can be implemented by conventional manufacturing and assembly of all-metal parts, or by additive manufacturing of the support frame associated with an assembly of patches obtained by printed technology.

[0128] It should be noted that, unless otherwise indicated or technically impossible, the different embodiments, variants and alternatives of the invention may be combined. The RF beam control device in particular may thus comprise one or more of the previously stated characteristics taken in isolation or according to any possible technical combinations.

[0129] Furthermore, the present invention is not limited to the embodiments described above by way of non-limiting example. It encompasses all the variant embodiments that may be envisaged by those skilled in the art. In particular, those skilled in the art will understand that the invention is not limited to the geometries of cells, of the frame corresponding to the radiating element, and of the excitation element described by way of non-limiting example.

Claims

Claims

1. Radiofrequency beam control device (10) defined in an orthogonal reference frame (X,Y,Z), the device (10) extending generally in the plane (X,Y) of said orthogonal reference frame (X,Y,Z), the device comprising an array of cells (100), each cell corresponding to a radiating element, said cell comprising a support frame (130) and an excitation element (150) of said radiating element, each radiofrequency beam being defined according to a given propagation direction having an angle of incidence 0 relative to said device, characterized in that said support frame (130) is inscribed in a generally tubular shape oriented along the Z axis of said orthogonal reference frame (X,Y,Z), said tubular shape having a given length dz along the axis of the frame Z and a cross-section defined in the plane (X,Y), said cross-section having a perimeter P, said support frame (130) comprising a frame entrance (131) and a frame exit (132),said support frame further comprising a number N of slots (133-n) extending, along the frame axis Z, between said frame outlet (132) and a slot position Zqr along the frame axis Z, said slot position Zqu being located between said frame inlet (131) and said frame outlet (132), each slot having a variable slot width along the frame axis Z, said slot width &n having a minimum slot value at said slot position Zq1v and a maximum slot value at the frame outlet (132), the maximum slot value O)™33- being determined as a function of the perimeter P of the cross-section and the number N of slots (133-n), the excitation element (150) comprising a number H of longitudinal metal ribs (152-h) arranged inside said tubular shape, a rib (152-h) extending along the frame axis Z between said frame inlet (131) and a rib position Zh,said rib position Zh being defined between said frame input (131) and said frame output (132), each cell (100) being configured to carry out an emission and / or a reception of radiofrequency beams invariant according to said propagation direction.,

2. A radio frequency beam control device (10) according to claim 1, wherein each slot (133-n) is associated with at least one of the following: least two slot edges (ni and n2), the slot edges representing the limits of the support frame (130) connecting said slot position ZOn to said frame output (132), each slot edge (ni, n2) being associated with a variability function (fnj f n2X said variability function being a concave and / or convex polygonal function.

3. Radiofrequency beam control device (10), according to one of the preceding claims, in which the number H of ribs (152-h) is equal to the number N of slots (133-n).

4. Radiofrequency beam control device (10), according to one of the preceding claims, in which the ribs (152-h) of the cell (100) are identical to each other and the slots (133-n) of the cell (100) are identical to each other, said rib position Zh being defined between said slot position Zqb and said frame output (132).

5. Radiofrequency beam control device (10), according to one of the preceding claims, wherein the excitation element (150) comprises a so-called "Vivaldi" antipodal transition (154) arranged at least partly inside said tubular shape, the transition (154) comprising at least a first metal etching 154-1 and a second metal etching 154-2 extending along the axis of the frame Z between said frame entrance (131) and an etching position Zgg, said etching position Zog being defined between said frame entrance (131) and said frame exit (132).

6. Radiofrequency beam control device (10), according to one of the preceding claims, wherein the excitation element (150) comprises a number T of planar metallic elements (156-t) arranged inside said tubular shape, a planar element (152-h) extending along the plane (X,Y) at a planar position Zt, said planar position Zt being defined between said frame inlet (131) and said frame outlet (132).

7. Radiofrequency beam control device (10), according to claim 6, wherein the slots (133-n) of the cell (100) are identical to each other, said planar position Zt being defined between said slot position Zqb and said frame output (132).

8. Radiofrequency beam control device (10), according to one of the preceding claims, in which the device (10) is in

9. metal part, and in which the cross-section has the shape of a circle or polygon. Method of manufacturing the radiofrequency beam control device (10) according to one of claims 1 to 8, characterized in that the device (10) is at least partially metallic, and the manufacturing method uses at least one 3D printing technique to manufacture said device (10).

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