Active polarizing cell, transmitting network and radio transmitting and receiving antennas

Abstract

Active Polarizing Cell, Transmitting Array, and Radio Transmitting and Receiving Antennas. The invention relates to a polarizing cell (C) configured to receive incident radiation on one side of the cell and to produce, from the incident radiation, on a second side of the cell opposite the first side, re-emitted radiation having circular polarization. The cell includes a switching mechanism (15) configured to produce, in a controlled manner, a first active phase shift of the incident radiation. Such a cell can be used in a reconfigurable transmitting array, in particular for use in the construction of a radio transmitting or receiving antenna. A beamforming and scanning function can be achieved by controlling the active phase shift in each cell of the transmitting array. Figure for the abstract: Fig. 2

Description

Title of the invention: Active polarizing cell, transmitting array and radio transmitting and receiving antennas technical field

[0001] The present invention relates to the field of radio frequency electronic engineering, in particular the field of design of reconfigurable transmitting array antennas. Its applications are particularly advantageous in satellite communications, high-speed communications, notably the 5G standard, and automotive radar. STATE OF THE ART

[0002] Transmitting arrays are increasingly used components for manufacturing efficient radio antennas for electromagnetic radiation wavelengths on the order of several millimeters. The X and Ka radio communication bands are particularly targeted by this new antenna technology. These arrays make it possible to provide high-gain radio antennas at lower production costs than array antennas, because the latter consist of multiple radiation sources out of phase with each other, instead of a single radiation source for each transmitting array radio antenna.

[0003] The article by J. Pages-Mounic et al., IEEE Access, 2021, Vol. 9, pp. 148302-148314, describes a transmitting network comprising juxtaposed cells, each capable of absorbing a portion of linearly polarized radiation from a source and re-emitting linearly polarized radiation. The re-emission polarization direction can be changed simply by modifying the orientation of a re-emitting portion of each cell.

[0004] To achieve high communication efficiency between a linearly polarized transmitted radio antenna and a linearly polarized receiving radio antenna, the polarization directions of the two antennas must be identical or substantially identical. In other words, an angular alignment step of the two radio antennas relative to each other around the transmission direction is necessary, which can be particularly detrimental or difficult to perform in certain circumstances, for example, in satellite communications. The use of circularly polarized beam radio antennas overcomes this difficulty.

[0005] Moreover, most transmission networks are based on the concept of the passive unit cell, that is to say, a cell whose phase of the transmission coefficient The beam direction is fixed by the geometric structure and remains unchanged after manufacturing. These are called fixed-beam transmitting arrays, whose radiation direction can only be modified by multi-source excitation or by moving the focal source. Both methods exhibit limited beam shifting due to the strong phase aberrations caused by passive phase correction. Although techniques exist to expand the angular coverage of passive transmitting arrays, these solutions have reduced aperture efficiency, slower beam shifting speed due to limitations in the mechanical movement of the focal source, and higher maintenance costs due to the presence of constantly moving mechanical parts.

[0006] An object of the present invention is therefore to provide a transmitting network capable of both re-emitting electromagnetic radiation with circular polarization and performing the beam formation and scanning function. SUMMARY

[0007] To achieve this objective, according to a first aspect of the invention, a polarizing cell is provided, configured to receive incident radiation on a first side of the cell, and to produce, from the incident radiation, re-emission radiation on a second side of the cell opposite to the first side, said cell comprising: - a portion of a metallic film, which is configured to form a ground plane for the cell and which is provided with a hole; - a first metallic plate, which is located on the first side of the cell relative to the portion of metallic film, which is parallel to said portion of metallic film and electrically insulated from said portion of metallic film, and which is configured to absorb at least partially the incident radiation; - a second metallic plate, which is located on the second side of the cell relative to the portion of metallic film, which is parallel to said portion of metallic film and electrically insulated from said portion of metallic film, and which is configured to produce re-emission radiation; and - a first electrical connection, which links the first metal plate to the second metal plate by passing through the portion of the metal film via the hole, while being electrically insulated from said portion of the metal film, the second metal plate having a pattern which includes the following parts of the second metal plate, - a first peripheral portion, which is contained between a first outer edge and a first circular inner edge, the first circular inner edge defining a first internal pattern zone of the second metal plate, and the first electrical connection ending at the center of the first circular internal edge; and - a first power supply segment, which radially connects the first circular inner edge to the first electrical connection, in the internal pattern area, the first metal plate comprising a switching element, said switching element being configured to produce in a controlled manner a first active phase shift of the incident radiation, and the pattern of the second metal plate further comprising the following other parts of the second metal plate, which are also in the internal pattern area: - a second feed segment, which terminates radially at the first circular inner edge, forming an angle between 80° and 100° with the first feed segment, the angle being measured at the center of the first circular inner edge; and - an intermediate band, which connects the first power supply segment at the first electrical connection to one end of the second power supply segment opposite the first circular inner edge, so that the first and second supply segments produce a second passive phase shift, transmitting to the first peripheral portion the first and second electric currents, respectively, and the intermediate band has a length such that the second electric current is delayed in phase quadrature with respect to the first electric current at the level of the first circular inner edge, when the incident radiation has a wavelength value that belongs to a resonance band of the cell to produce re-emission radiation from the incident radiation.

[0008] The cell described above is a reconfigurable cell, combining both a polarizer function and a phase shifter function. Indeed, the reconfigurable and active aspect of the cell is achieved thanks to the switching element added to the first metal plate. The phase of the cell's transmission coefficient can be controlled by the polarization state of the components of the switching element. The first active phase shift produced by the switching element can be electronically regulated, making it possible to obtain a controllable phase shift of 0° or 180°.

[0009] As for the polarization conversion, this is achieved by the combined action of the first and second metal plates. Indeed, during use of the polarizing cell of the invention, the first electrical connection transmits to the second metal plate a variable electric current resulting from the absorption of the incident radiation by the first metal plate. This electric current is then transmitted to the first peripheral portion of the second metal plate simultaneously, partly by the first power supply segment of the second metal plate, and partly by its second power supply segment. Thanks to the second quadrature phase shift produced by the pattern of this second metal plate between the respective portions of electric current transmitted by the two power supply segments, and due to the angle between the respective connections of these two power supply segments to the first circular inner edge of the first peripheral portion of the second metal plate, these transmitted portions of electric current generate in the first peripheral portion an electric current that rotates around the internal pattern area.This rotating electric current then produces the re-emission radiation field with a circular polarization and a determined direction of rotation, and with a high level of purity compared to the other direction of rotation of circular polarization.

[0010] A polarizing cell according to the invention can be used simultaneously as a circular polarizer and as a reconfigurable phase shifter. Furthermore, if the first metal plate is adapted to absorb incident radiation when it has a specific polarization, different from the circular re-emission polarization produced by the pattern of the second metal plate, the polarizing cell performs a polarization conversion function. In particular, if the first metal plate is adapted to absorb incident radiation when it has a specific linear polarization, the polarizing cell of the invention performs a function of converting this linear polarization into circular polarization.

[0011] Such a reconfigurable polarizing cell eliminates the need for the integration of potentially expensive external polarizers or phase shifters. This cell can be manufactured using one of the available technologies, particularly printed circuit board-based technologies. Its cost, as well as that of a transmitter network composed of such cells, can therefore be low.

[0012] A second aspect of the invention relates to a transmitting network comprising a plurality of identical cells, juxtaposed with each other such that the portions of metallic film extend continuously between neighboring cells, to form a flat screen with holes, the cells being arranged such that the respective first metallic plates of said cells are all on the same side of the transmitting network, and the cells being spaced parallel to the flat screen with holes such that: the respective first metallic plates are disjointed, the respective second metallic plates are disjointed, the respective third metallic plates, when said third metallic plates are present in the cells, are disjointed, and the respective metallic levels, when the said metallic levels are present in the cells, they are also disjoint.

[0013] The transmitter network, based on reconfigurable, polarizing unit cells, enables dynamic beam formation and scanning by controlling the polarization of the active components of the network, thanks to the integration of a switching element in each cell. This allows targeting oblique beam angles with minimal gain loss and without significant distortion of the re-emitted radiation beam. Beamforming techniques can be used to synthesize radiation pattern shapes controlled in real time according to the dynamic coverage requirements of the transmitter network in question.

[0014] This network allows for the direct generation of circular polarization at the network output, without the use of external polarizers, which could lead to additional losses and high costs, or the use of sequential rotation techniques, which could induce losses on the order of 3 dB in the case of a linearly polarized cell. Thus, by using a reconfigurable cell according to the invention, a low-cost focal source can be employed. As the majority of SatCom applications operate with circular polarization, this becomes very advantageous for low-cost terminals. Furthermore, this network exhibits a wide gain bandwidth (15%) and, at the same time, a very low ellipticity ratio (less than 3 dB over more than 20% of the bandwidth) with a single radiating aperture. This reconfigurable network achieves power efficiencies exceeding 21%.

[0015] A third aspect of the invention relates to a radio transmitting antenna comprising: - a source, configured to produce electromagnetic radiation exhibiting a polarization state; - a transmitting network, arranged opposite a radiation output of the source, a first face of the transmitting network which is opposite the radiation output of the source having the first metal plates, in which the patterns of the first metal plates are configured to absorb the radiation produced by the source, as incident radiation for each cell of the transmitting network, in accordance with the polarization state of said incident radiation as produced by the source.

[0016] A fourth aspect of the invention relates to a radio receiving antenna comprising: - a detector, configured to detect received radiation exhibiting a polarization state prescribed for said detector; and - a transmitter network, positioned opposite the detector, with the first face of the transmitter network facing the detector and featuring the first metal plates, in which the pattern of the first metal plates is adapted to the polarization state prescribed for the detector, such that when external radiation having a circular polarization allowing absorption of said external radiation by the second metal plates of the transmitting array arrives on a second face of said transmitting array opposite the first face of the transmitting array, the first metal plates re-emit towards the detector the received radiation having the polarization state prescribed for said detector.

[0017] A fifth aspect of the invention relates to a method for converting the polarization state, using a polarizing cell, of incident radiation having a first polarization state, by producing from the incident radiation re-emission radiation having a second polarization state, said method comprising: - reception of incident radiation on the first side of the cell; - at least partial absorption of the incident radiation by the first metallic plate; - a first active and controlled phase shift of the absorbed incident radiation, produced by the switching element; - a production of re-emission radiation by the second metallic plate, from the incident radiation, said production comprising: • a second passive phase shift produced by the first and second supply segments, during a transmission to the first peripheral portion of the first and second electric currents, respectively, the second electric current being delayed in quadrature of phase with respect to the first electric current at the level of the first circular inner edge, when the incident radiation has a wavelength value which belongs to a resonance band of the cell. BRIEF DESCRIPTION OF THE FIGURES

[0018] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0019] [Fig.1] Fig.1 schematically illustrates a cross-sectional view of a polarizing cell according to an example embodiment.

[0020] [Fig.2] Fig.2 schematically illustrates a perspective view of the metallic layers of the polarizing cell according to an example embodiment.

[0021] [Fig.3A] Fig.3A schematically illustrates a plan view of a portion of a metallic film of the polarizing cell according to an example of an embodiment.

[0022] [Fig.3B] Fig.3B schematically illustrates a plan view of a second metal plate of the polarizing cell according to an example embodiment.

[0023] [Fig.3C] Fig.3C schematically illustrates a plan view of a first metal plate of the polarizing cell according to an example of an embodiment.

[0024] [Fig.3D] The [Fig.3D] schematically illustrates a plan view of a third metal plate of the polarizing cell according to an example of an embodiment.

[0025] [Fig.3E] Fig.3E schematically illustrates a plan view of a metallic power supply level for the polarizing cell according to an example embodiment.

[0026] [Fig.4A] Fig.4A schematically illustrates a view of an input plane of a transmitting network according to an example embodiment.

[0027] [Fig.4B] Fig.4B schematically illustrates a view of part of another plane of the transmitting network according to an example embodiment.

[0028] [Fig.5A] Fig.5A schematically illustrates a "1-bit" phase distribution of a transmitting network, according to an example embodiment.

[0029] [Fig.5B] Fig.5B schematically illustrates a "pseudo 2-bit" phase distribution of a transmitting network, according to an example embodiment.

[0030] [Fig.6A] Fig.6A schematically illustrates a schematic view of a transmitting array antenna according to an example embodiment.

[0031] [Fig.6B] Fig.6B schematically illustrates a schematic view of a receiving antenna with a transmitting array according to an example embodiment.

[0032] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. In particular, the thicknesses and / or dimensions of the different layers, patterns and reliefs are not representative of reality. DETAILED DESCRIPTION

[0033] Before proceeding with a detailed review of embodiments of the invention, optional features that may be used in combination or alternatively are listed below:

[0034] According to one example, the cell comprises a metallic feed level located between the portion of metallic film and the first metallic wafer, the metallic feed level being parallel to the portion of metallic film and electrically insulated from the portion of metallic film, the metallic feed level being configured to supply the switching element with an electric current through two second electrical connections linking the metallic power level to the first metallic plate.

[0035] The metallic power supply level delivers a direct current to the switching element of a cell. This metallic power supply level is itself powered by an electronic circuit external to the cell or the transmitting network comprising a plurality of cells. This circuit is advantageously independent of the transmitting network, which allows it to be implemented using different technologies independently of the transmitting network.

[0036] According to one example, the metallic feed level includes feed lines. These feed lines may exhibit high impedance due to their small width in a plane parallel to the metallic film portion.

[0037] According to one example, the metallic power supply level includes metallic pads configured to electrically connect the power lines to the secondary electrical connections. These metallic pads, forming capacitors, can be manufactured by printing. This improves the decoupling between electromagnetic radiation and direct current.

[0038] According to one example, the two second electrical connections are vias arranged along an axis, called the cell axis, perpendicular to the portion of metallic film, on either side of the switching element, so that the connections of said vias with the first metallic plate are located in areas of the first metallic plate where the electric field is substantially zero.

[0039] The arrangement of the vias connecting the power supply metal level to the first metal plate, in a plane where the electric field is zero, prevents coupling between the power supply metal level and the radio frequency (RF) current present in the first metal plate. These vias allow the first metal plate to be biased with a DC voltage to control the biasing states of the active components of the switching element.

[0040] According to one example, the metallic feed level is separated from the portion of metallic film by a distance along an axis, called the cell axis perpendicular to the portion of metallic film, between 89 pm and 178 pm.

[0041] This distance promotes the formation of a capacitance between the metal pads and the ground plane formed by the portion of metal film, which makes it possible to reduce the parasitic radiation that can be generated by the power lines.

[0042] According to one example, the switching element comprises at least two active components, configured to exhibit opposite polarization states controlled by the electric current transmitted through the two second electrical connections.

[0043] By controlling the opposing polarization states of the active components of a cell, the initial phase shift of the incident radiation can be controlled. Indeed, the direction of the electric current used to polarize the active components can be reversed, resulting in a phase shift from 0° to 180°. This control of the polarization state of the active components is performed independently from one cell to another. Thus, by applying a specific voltage distribution to the different cells in the radiating aperture of a transmitting array, manipulation of the wavefront of the incident radiation is possible. This allows modification of the characteristics of the incident radiation. For example, the re-emitted radiation beam can exhibit a higher gain at the aperture output compared to the incident radiation during beam formation.The direction of the maximum re-emitted radiation beam can be redirected, allowing for the scanning of the re-emitted radiation beam.

[0044] According to one example, the pattern of the first metal plate comprises the following parts of the first metal plate: - a second peripheral portion, which is contained between a second outer edge and a second circular inner edge, the second circular inner edge delimiting a second internal pattern zone of the first metal plate, and the first electrical connection terminating at the center of this second circular inner edge; and - a third power supply segment in the second internal pattern area of ​​the first metal plate, said third power supply segment comprising a central part in which the connection of the first electrical connection with the first metal plate is located, and two peripheral parts disposed on either side of the central part, the two peripheral parts radially connecting, on either side of the central part, the second circular internal edge to the first electrical connection and each of the two peripheral parts comprising one, different, of the at least two active components, said third power supply segment being configured to transmit to the at least two active components the electrical current transmitted by the two second electrical connections.

[0045] According to one example, the at least two active components are taken from the following group of active components: PIN type diodes, Varactor type diodes, microelectromechanical systems (MEMS) and phase change materials (PCM).

[0046] Varactor diodes (also known as variable reactor diodes) can be used for certain frequencies such as the C-band. PIN diodes (Positive Intrinsic Negative) are commonly These PIN-type diodes are used in the design of reconfigurable transmitter networks. They exhibit relatively low losses and can operate in a frequency range up to 50 GHz, enabling their use in millimeter wave bands, such as the Ka-band. MCP materials can operate in higher millimeter wave frequencies (towards the 110 GHz band).

[0047] According to one example, the second metal plate includes a conductive arm, the cell further comprising a third electrical connection linking the second metal plate to the portion of metal film through the conductive arm.

[0048] The conductive arm acts as a high-impedance quarter-wave transmission line, ensuring a connection between the first metal plate and ground via the third electrical connection. The second metal plate is connected to the first metal plate, through which a direct current flows, potentially causing interference with the RF currents. The second metal plate is circularly polarized, and no zero electric field is present in the plane of the second metal plate. The conductive arm creates an open circuit at its input, thus isolating the RF current from ground and preventing a short circuit. Only the electrical currents intended to bias the active components can pass through the third electrical connection.

[0049] According to one example, the intermediate strip has a connecting part and a curved part, the connecting part connecting the first power segment at the first electrical connection to a first end of the curved part, and a second end of said curved part being connected to the end of the second power segment opposite the first circular inner edge.

[0050] With such a shape, the intermediate band can have a characteristic impedance that is continuous or constant throughout its length, so that it does not produce significant reflection for the portion of the electrical current it transmits to the second power supply segment. The polarizing cell thus exhibits a lower effective reflection rate for the incident radiation. In other words, a larger proportion of the incident radiation is converted into re-emitted radiation. Furthermore, this two-part design of the intermediate band—that is, with the connecting portion and the curved portion—allows for easy adjustment of the total length of the intermediate band to produce the quadrature phase shift between the two portions of electrical current that are transmitted separately by the two power supply segments to the first peripheral portion of the second wafer.Preferably, the curved portion of the intermediate band may have an arc-like shape within the pattern area, with an angular extension between 210° and 270°. Such a shape in . The arc of the curved part also helps to reduce parasitic inductances that could degrade the operation of the polarizing cell.

[0051] According to one example, the polarizing cell can be dimensioned so that the resonance band of this cell is between 8 GHz (Gigahertz) and 12 GHz, corresponding to the X band.

[0052] According to one example, the polarizing cell can be dimensioned so that the resonance band of this cell is between 26.5 GHz and 40 GHz, corresponding to the Ka band.

[0053] However, the polarizing cell of the invention can alternatively be dimensioned so that its resonance band is in other spectral domains assigned to listed types of radio communication.

[0054] According to one example, the cell further comprising, on the second side of the cell and on one side of the second metal plate which is opposite the portion of metal film, a third metal plate which is parallel to the portion of metal film, and which is electrically insulated from each of said portion of metal film and of the first and second metal plates, the third metal plate having a shape with rotational symmetry about the cell axis, which passes through the center of the first circular inner edge of the second metal plate and which is perpendicular to the portion of metal film.

[0055] Such a third metal plate is therefore electromagnetically coupled at a distance to the second metal plate. It makes it possible to broaden the frequency band within which the polarizing cell is effective.

[0056] According to one example, the third metal plate is an annular strip which is centered with respect to the cell axis.

[0057] According to one example, the third metal plate has dimensions adapted to widen the resonance band of the cell, compared to said cell when it is devoid of a third metal plate.

[0058] According to one example, the first metal plate has a pattern configured such that said first metal plate has an absorption efficiency that is greater for a first linear polarization of the incident radiation, compared to a second linear polarization of said incident radiation perpendicular to the first polarization.

[0059] In the transmitting network, the cells can be arranged in a matrix configuration, located at the intersections of rows and columns of a matrix. A matrix step, parallel to the rows and columns, can be substantially equal to half a wavelength value associated with a frequency value within the cell bandwidth. The relationship between a value of wavelength, denoted X, and the associated frequency value, denoted f, is: X = C / f where C is the speed of propagation of electromagnetic radiation in a vacuum.

[0060] According to one example, in the transmitting network, the switching elements of each of the plurality of cells are electrically supplied by supply voltages independently of each other.

[0061] These independent supply voltages between the cells of the transmitting network allow total control over the phase distribution in the radiating aperture of the network. Electronic beam formation and scanning can thus be performed in all 2D planes.

[0062] This phase distribution, produced by the active control of the two active components of the switching element in each cell, is known as "1-bit" because only two phase states are used. The use of a "1-bit" configuration represents a compromise between network opening efficiency, network manufacturing complexity, and the reliability of the final product.

[0063] According to one example, in the transmitting array, the respective first metal plates of the cells are all oriented identically within an input plane which is parallel to the perforated planar screen, and in which the respective second metal plates of the cells have variable orientations within another plane which is also parallel to the perforated planar screen, said variable orientations being adapted to produce a beamforming function for radiation which is re-emitted by the transmitting array.

[0064] Furthermore, when several identical polarizing cells conforming to the invention are juxtaposed to form a transmitting array, an angular deviation between the respective orientations of the second metal plates of two of these polarizing cells, within a plane common to these second metal plates, produces the same angular deviation between the respective instantaneous fields re-emitted by the two cells. Due to the circular polarization of the re-emitted field, this angular deviation is equivalent to a passive phase shift of the same magnitude between the radiation re-emitted separately by the two cells. A suitable selection of the respective orientations of the second metal plates of all the cells in this transmitting array therefore makes it possible to easily produce beamforming for the radiation re-emitted by the entire transmitting array.Since the orientation angle of each second metallic plate is a continuous variable, the beamforming function can be achieved with great precision using cells conforming to the invention. The re-emitted radiation beam can thus exhibit low divergence and have reduced radiative power in the secondary lobes of the beam.

[0065] This passive phase distribution at the second and / or third metal plates of the transmitting array can thus be used within a special configuration of the transmitting array to generate a so-called "pseudo 2-bit" phase correction, thereby widening the angular range of pointing at low ellipticity and thus widening the field of view of the array. This configuration is still a correction of the "1-bit" configuration, but the multi-state distribution of passive phase at the second and / or third metal plates improves the performance of the transmitting array, particularly in pointing the re-emission radiation beam.

[0066] It is specified that, within the framework of the present invention, the terms "on", "overcomes", "covers", "underlying", "opposite" and their equivalents do not necessarily mean "in contact with". Thus, for example, the arrangement of a first layer on a second layer does not necessarily mean that the two layers are directly in contact with each other, but means that the first layer at least partially covers the second layer by being either directly in contact with it, or by being separated from it by at least one other layer or at least one other element.

[0067] A substrate is understood to be a layer based on a species A, a substrate, a layer comprising only that species A or that species A and possibly other species.

[0068] A parameter "approximately equal to / greater than / less than" a given value means that this parameter is equal to / greater than / less than the given value, to within ±10% of that value. A parameter "approximately between" two given values ​​means that this parameter is at least equal to the smaller of the given values, to within ±10% of that value, and at most equal to the larger of the given values, to within ±10% of that value.

[0069] It is specified that, within the framework of the present invention, the thickness of a layer or substrate is measured along a direction perpendicular to the surface along which this layer or substrate has its maximum extent. The thickness is thus taken along a direction perpendicular to the principal faces of the layer or substrate on which the different layers rest.

[0070] The steps of the process are understood in the broad sense as the implementation of a part of the process and may optionally be carried out in several substeps. Several embodiments of the invention implementing successive steps of the polarization state conversion process are described below. Unless explicitly stated, the adjective "successive" does not necessarily imply, although this is generally preferred, that the steps follow each other immediately; intermediate steps may separate them.

[0071] Furthermore, the term "step" does not necessarily mean that the actions carried out during a step are simultaneous or immediately successive. Certain actions of a first step may, in particular, be followed by actions related to a different step, and other actions from the first step may be repeated later. Thus, the term "step" does not necessarily imply unitary actions that are inseparable in time and in the sequence of phases of the process.

[0072] A polarizing cell C is now described with reference to Figures 1 to 3E, according to an example of an embodiment.

[0073] As illustrated in [Fig. 1], the polarizing cell C comprises a first metal plate 1 carried by a face of a first dielectric layer 50 which is opposite an input plane Pin of the cell C. The cell C further comprises a portion of metal film 2 carried by a face of a second dielectric layer 60 which is opposite the input plane Pin. The first metal plate 1 is parallel to the portion of metal film 2, and electrically insulated from said portion of metal film 2. The cell C further comprises a second metal plate 3, which is preferably parallel to the portion of metal film 2 and electrically insulated from the portion of metal film 2. The second metal plate 3 is carried by the other face of the second layer 60 which is opposite an output plane Pout of the cell C, opposite the input plane Pin.

[0074] The cell C is configured to receive an incident radiation Rin on its input plane Pin, and to produce, from the incident radiation Rin, a re-emission radiation Rout from its output plane Pout.

[0075] The first metal plate 1 of cell C includes a switching element 15, configured to produce in a controlled manner a first active phase shift of the incident radiation Rin.

[0076] The cell C may further comprise a third metal plate 4, carried by a third dielectric layer 70, on a face of the third dielectric layer 70 that is opposite the exit plane Pout. The third metal plate 4 is preferably parallel to the portion of metal film 2, and electrically insulated from each of the portion of metal film 2 and from the first and second metal plates 1, 3.

[0077] The cell C may also include a metallic power supply level 5, carried on the other side of the first dielectric layer 50 that faces the exit plane Pout. The metallic power supply level 5 is located between the portion of the metallic film 2 and the first metallic wafer 1. The metallic power supply level 5 is preferably parallel to the portion of the metallic film 2 and electrically isolated from the portion of the metallic film 2.

[0078] The first, second, and third dielectric layers 50, 60, 70 can be assembled together by a first 56 and a second 67 assembly layers, commonly called pre-preg. The set of dielectric layers, assembly layers, and metallic layers forms a stack of superimposed layers along an axis, called the cell axis AA, which is preferably perpendicular to the portion of metallic film 2, and to the inlet plane Pin and outlet plane Peut.

[0079] The metal plates 1, 3, and 4 may have respective thicknesses of approximately 43 µm (micrometers), 43 µm, and 35 µm. The metal film portion 2 may have a thickness of approximately 17 µm. The first and second dielectric layers 50 and 60 may have a thickness of approximately 1.524 mm and a relative permittivity of approximately 3.55. The third dielectric layer 70 may have a thickness of approximately 7.575 mm and a relative permittivity of approximately 2.2. The first assembly layer 56 may have a thickness of approximately 90 µm and a relative permittivity of approximately 3.52. The second assembly layer 67 can have a thickness of approximately 50 pm and a relative dielectric permittivity of approximately 2.7.

[0080] The polarizing cell C is preferably sized to operate within the X band, with a central bandwidth wavelength, denoted X, of approximately 28.6 mm, corresponding to an electromagnetic radiation frequency, denoted f, of 10.5 GHz. Cell C preferably has a square shape parallel to the Pin and Pout planes, with sides of approximately X / 2 = 14.3 mm.

[0081] The portion of metallic film 2 forms a ground plane for the cell C and is provided with a hole 20. The first metallic plate 1 is configured to absorb at least partially the incident radiation Rin. The second metallic plate is configured to produce the re-emission radiation Rout.

[0082] Figure 2 illustrates a three-dimensional view of cell C, in which the dielectric layers and assembly layers are hidden. Only the metallic layers are visible in Figure 2.

[0083] As illustrated in Figures 1 and 2, cell C further comprises a first electrical connection 81 which links the first metal plate 1 to the second metal plate 3 by passing through the portion of metal film 2 via the hole 20, while being electrically insulated from the portion of metal film 2. The first electrical connection 81 passes through the stack of the different layers of cell C, parallel to the axis of cell AA. The first electrical connection 81 preferably a via. The via can be made of a copper-based alloy, and have an external radius of 0.15 mm.

[0084] The cell C may also include two second electrical connections 82, linking the metal supply level 5 to the first metal plate 1, passing through the first dielectric layer 50, preferably parallel to the axis of the cell AA. The metal supply level 5 is thus configured to supply the switching element 15 with an electric current through the second electrical connections 82.

[0085] The switching element 15 may comprise at least two active components 15a, 15b, configured to exhibit opposite polarization states. These polarization states may be controlled by the electric current transmitted through the two second electrical connections 82 to the first metal plate 1.

[0086] The two second electrical connections 82 are preferably vias arranged along the cell axis AA on either side of the active components 15a, 15b, of the switching element 15. The connections of these vias to the first metal plate 1 are preferably located in areas of the first metal plate 1 where the electric field is substantially zero. This prevents coupling between the metal supply level 5 and a radio frequency (RF) current present in the first metal plate 1. These vias allow the first metal plate 5 to be biased with a DC voltage to control the biasing states of the switching element 15.

[0087] The geometries of the different metallic layers of cell C are now described with reference to figures 3A to 3E.

[0088] As illustrated in [Fig. 3A], the portion of metallic film 2 extends in a principal extension plane of cell C parallel to the Pin and Pout planes. This extension of the portion of metallic film 2 is continuous except at the hole 20, which is preferably circular and centered on the axis AA. The hole 20 provides electrical insulation of the portion of metallic film 2 from the first electrical connection 81. To prevent a short circuit of the first electrical connection 81, the diameter of the hole 20 is larger than that of the first electrical connection 81. The hole 20 may have a radius of approximately 0.3 mm.

[0089] As illustrated in [Fig. 3B], the second metal wafer 3, which is adapted to produce the Rout re-emission radiation with circular polarization, also has a pattern. This pattern of the second metal wafer 3 comprises a first peripheral portion 30, continuous between a first outer edge 31, which is preferably square, and a first circular inner edge 32. The pattern further comprises a first feed segment 33, preferably straight, a second feed segment 34, preferably straight, and an intermediate band 35.

[0090] The first circular inner edge 32 defines a first internal zone of the pattern of the second metal plate 3. The first circular inner edge 32 is centered on the axis AA. The first electrical connection 81 terminates at the center of the first circular inner edge 32. The first power supply segment 33 radially connects the first circular inner edge 32 to the first electrical connection 81. The second power supply segment 34 terminates radially at the first circular inner edge 32, forming an angle θ with the longitudinal direction of the first power supply segment 33, around the axis AA. The angle θ may be between 80° and 100°, and is preferably equal to 90°.

[0091] The intermediate strip 35 connects two respective ends 33e and 34e of the feed segments 33 and 34, which are opposite the circular inner edge 32. In the embodiment shown, the intermediate strip 35 consists of a connecting portion 35a and a curved portion 35b. The curved portion 35b can have an angular extension of approximately 240° around the axis AA, and the two portions 35a and 35b are arranged in series to connect the end 33e of the first feed segment 33 to the end 34e of the second feed segment 34. The method for determining the total length of the intermediate strip 35 will be described later.

[0092] The first outer edge 31 of the second metal plate 3 has dimensions Lpatch3 and Wpatch3. Preferably, Lpatch3 and Wpatch3 are identical and can be on the order of 6.13 mm. The first circular inner edge 32 of the second metal plate 3 has a radius Rcyi3, which is preferably equal to 2 mm. The first feed segment 33 of the second metal plate 3 has a width Wiine3, which is preferably equal to 0.44 mm. The second feed segment 34 and the intermediate strip 35, in its two parts 35a and 35b, have a common width Wstrip3, which is preferably equal to 0.43 mm.

[0093] As illustrated in [Fig. 3B], the second metal plate 3 may, for example, include a conductive arm 36. According to this example, the cell C includes a third electrical connection 83 linking the second metal plate 3 to the portion of metal film 2 through the conductive arm 36. The third electrical connection 83 may be a via that passes through the second dielectric layer 60, preferably parallel to the axis of the cell AA, as illustrated in [Fig. 1]. The biasing of the active components 15a, 15b is preferably achieved with a DC (Direct Current) voltage, the voltage being negative or positive and denoted ±VCC. This ±VCC voltage is preferably applied by a single supply line. Consequently, the second metal plate 3 is advantageously referenced to the ground plane formed by the portion of metal film 2.

[0094] The conductive arm 36 forms a high-impedance quarter-wave line, which ensures a connection of the first metal plate 1 to ground via the third electrical connection 83. The second metal plate 3 is connected to the first metal plate 1, through which a direct current flows. This can cause interference with the RF currents. Since the second metal plate 3 is circularly biased, no zero electric field is present in the plane of the second metal plate 3. It is therefore advantageous to isolate the RF current from the ground connection to prevent a short circuit. The conductive arm 36 creates an open circuit at its input. In this way, the RF current considers the ground connection as an open circuit, thus preventing a short circuit. Only the DC bias currents of the active components 15a, 15b can pass through the third electrical connection 83.This conductive arm 36 is therefore optimized to improve the radiating system, taking into account the DC biasing circuit.

[0095] As illustrated in [Fig. 3C], the first metal plate 1, which is suitable when the incident radiation Rin has linear polarization, has a pattern. This pattern of the first metal plate 1 comprises a second peripheral portion 10, continuous between a second outer edge 11 and a second circular inner edge 12. The second circular inner edge 12 delimits a second internal pattern area of ​​the first metal plate 1. The second circular inner edge 12 is preferably centered on the axis AA. The first electrical connection 81 terminates at the center of this second circular inner edge 12.

[0096] The design of the first metal plate 1 further includes a third power supply segment 13 in the second internal zone. The third power supply segment 13 includes a central portion in which the connection of the first electrical connection 81 to the first metal plate 1 is located, as illustrated in [Fig. 3C]. The third power supply segment 13 further includes two peripheral portions arranged on either side of the central portion. The two peripheral portions radially connect, on either side of the central portion, the circular inner edge 12 to the first electrical connection 81. Each of the two peripheral portions includes one of the two active components 15a, 15b. The third power supply segment 13 allows the electrical current transmitted by the two second electrical connections 82 to be supplied to the two active components 15a, 15b, in order to bias them under direct current.

[0097] The active components 15a, 15b, of the switching element 15 are preferably connected in an "antiparallel" manner. They are thus biased with voltages of opposite signs, which allows their biasing states to be controlled with a single power supply line. This control of the polarization states of the active components 15a, 15b, allows electronic control of the transmission phase of cell C.

[0098] The active components 15a, 15b can be, for example, PIN diodes (Positive Intrinsic Negative). PIN diodes are commonly used in the design of reconfigurable transmitter networks. Their ease of use and relatively low losses explain this preference. The active phase shift of the radiation can be regulated by electronically controlling the bias state of the PIN diodes. The bias voltage applied to each diode can be +5 V or -5 V. Reversing the sign of the voltage reverses the direction of the current in the first metal plate 1, resulting in a controllable phase shift of 0° or 180°.

[0099] Other types of active components 15a, 15b, can be used, such as Varactor diodes (also known as variable reactor diodes), microelectromechanical systems (MEMS), or phase-change materials (PCMs). Varactor diodes can be used for certain frequencies such as the C-band. PCMs can operate in the high millimeter wave frequencies (towards the 110 GHz band).

[0100] Commercially available and manufactured PIN diodes for frequencies up to 50 GHz are available. These PIN diodes allow their use in millimeter-wave bands, such as the Ka band. Furthermore, the biasing of PIN diodes is relatively simple compared to that of MEMS components.

[0101] As illustrated in [Fig. 3C], the second outer edge 11 of the first metal plate 1 has dimensions Lpatchi and Wpatchi. Preferably, Lpatchi and Wpatchi are identical and can be on the order of 6.13 mm. The circular inner edge 12 of the first metal plate 1 has a radius Rcyn, which can be on the order of 2 mm. The third feed segment 13 has a width Wiinei, which is preferably on the order of 0.46 mm. Such a first metal plate 1 is suitable for absorbing the incident radiation Rin when this incident radiation has a linear polarization of its electric field that is parallel to the longitudinal extension direction of the third feed segment 13.

[0102] As illustrated in [Fig. 3D], the third metal plate 4 has a pattern adapted to widen the bandwidth of cell C. This pattern of the third metal plate 4 can be an annular band bounded between a circular outer edge 41 and a circular inner edge 42. The two edges 41 and 42 are preferably centered on the axis AA. The third metal plate 4 is electrically isolated from all the other metal layers of cell C. Its effect on the operation of cell C results from electromagnetic coupling. the distance that exists between the second metal plate 3 and the third metal plate 4. The outer circular edge 41 and the inner circular edge 42 have radii Rcyl_ext4 and Rcyl_int4, respectively. These radii are two dimensional parameters that can be adjusted to control the broadening of the resonance band of cell C. The radius Rcyl_ext4 can be on the order of 3.7 mm and the radius Rcyl_int4 can be on the order of 1.2 mm.

[0103] As illustrated in [Fig. 3E], the metallic supply layer 5, known as the "biasing layer," may include 51 and 52. The supply lines 52 are routed in the plane of the metallic supply layer 5, which is preferably parallel to the portion of metallic film 2. The supply lines 52 may be connected to an electrical circuit external to cell C. The supply lines 52 are thus supplied with DC voltages through the external electrical circuit. These supply lines 52 may exhibit high impedance due to their narrow width in the plane of the metallic supply layer 5.

[0104] The metal feed level 5 may further comprise metal pads 51 arranged on either side of the axis of cell AA, in the plane of the metal feed level 5, as illustrated in [Fig. 2]. These metal pads 51 preferably have a rectangular shape. They allow the power lines 52 to be electrically connected to the second electrical connections 82. The connections of the second electrical connections 82 to the metal pads 51 may preferably be located at the center of the metal pads 51.

[0105] These metal pads 51 can be manufactured by printing, for example, and form capacitors that improve the decoupling between the DC bias current and the RF current present in cell C. These capacitors are formed between the metal pads 51 and the ground plane of the metal film portion 2. The latter is separated from the metal feed layer 5 by the first assembly layer 56, which preferably has a thickness on the order of a few hundred micrometers. This thickness is sufficiently thin to bring the metal film portion 2 closer to the metal feed layer 5, thus promoting capacitor formation and reducing parasitic radiation from the feed lines 52. The face of the metal film portion 2 that faces the Pin plane is separated from the surface of the metal pads 51 that faces Pout by a distance d25 taken along the axis of cell AA.The choice of the d25 distance depends on the specifications of cell C, and can be between 89 pm and 178 pm.

[0106] This cell C enables the conversion of the polarization state of the incident radiation Rin by producing re-emission radiation Rout having a polarization state different from that of the incident radiation Rin, according to the process described below. The process of converting the polarization state by the Cell C may include a stage for receiving the incident radiation Rin on the first metal plate 1, at the inlet plane Pin. This incident radiation Rin on the first metal plate 1 may, for example, exhibit linear polarization. The process further includes at least partial absorption of the incident radiation Rin by the first metal plate 1. This absorption by the first metal plate 1 depends on the architecture of the first metal plate 1, particularly its pattern.

[0107] The method further comprises a first active and controlled phase shift of the absorbed incident radiation Rin, produced by the switching element 15. This first active phase shift is controlled by applying a DC voltage to the first metal plate 1, which biases the active components 15a, 15b, of the switching element. The method also comprises the production of re-emission radiation Rout by the second metal plate 3, from the incident radiation Rin. This step of producing the re-emission radiation Rout includes a second passive phase shift produced by the first 33 and second 34 power supply segments. This second phase shift is produced during the transmission of the first and second electric currents, respectively, to the first peripheral portion 30.The second electric current is delayed in quadrature phase relative to the first electric current at the level of the first circular inner edge 32, in particular when the incident radiation Rin has a wavelength value which belongs to a resonance band of the cell C.

[0108] Indeed, when cell C receives the incident radiation Rin on the first metal plate 1, in the input plane Pin, this radiation Rin induces electric currents within the first metal plate 1, which cause at least partial absorption of the radiation Rin's power. For the first metal plate 1 arrangement described above, this absorption is maximal when the incident radiation Rin is linearly polarized with its electric field parallel to the longitudinal direction of the third feed segment 13. The portion of metal film 2 produces a screening effect for a residual portion of the incident radiation Rin that has not been absorbed by the first metal plate 1. To enhance this screening effect of the portion of metal film 2, it can be connected to an electrical ground terminal. Thus, the portion of metal film 2 constitutes a ground plane for cell C.The electric currents that were generated by the incident radiation Rin in the first metal plate 1 are transmitted to the second metal plate 3 by the first electrical connection 81, through the portion of metal film 2.

[0109] By an electrical operation inverse to that which occurred in the first metal plate 1, these electric currents which arrive at the plate 3 by the first electrical connection 81 are transmitted to the peripheral portion 30 of the latter by each of the supply segments 33 and 34. The part of these electric currents which is transmitted by the supply segment 33 produces a component of the re-emission radiation Rout which has a linear polarization parallel to this supply segment 33. Simultaneously, the other part of the electric currents, transmitted by the supply segment 34, produces another component of the re-emission radiation Rout which has a polarization parallel to this other supply segment 34.

[0110] The intermediate strip 35 is designed to have a total length that produces a transmission delay of one phase quadrature for the electrical currents it transmits. This total length can be easily adjusted by selecting the angular orientation of the connecting portion 35a with respect to the longitudinal direction of the supply segment 33, and adapting accordingly the angular length of the curved portion 35b to join the supply segment 34.Given that the two feed segments 33 and 34 are perpendicular (0=90°), and that the intermediate band 35 delivers to the peripheral portion 30, via the feed segment 34, the part of the electric currents it transmits with a delay of one quadrature with respect to the part of the electric currents that is transmitted by the feed segment 33, the two components of the re-emission radiation Rout combine to produce this re-emission radiation with a circular polarization.

[0111] The widths Wiine3 and Wstlip3 can be selected so that the electrical currents transmitted by the supply segments 33 and 34, respectively, have equal amplitudes. The complementary effect of the optional third metal plate 4 has already been described above. This second phase shift produced by the conjunction of the second 3 and the third 4 metal plates is a so-called "passive" phase shift because it depends on the geometry of these two metal layers and cannot be controlled dynamically. Once cell C is manufactured, this second passive phase shift remains unchanged.

[0112] A transmitting network 100 comprising a plurality of cells C, is now described with reference to Figures 4A to 5B.

[0113] As illustrated in [Fig. 4A], the transmitter network 100 can be fabricated by placing a large number of C cells, as described above, on large printed circuit boards. These C cells are arranged side by side in a plane parallel to the Pin plane, so as to form a matrix of C cells having Nx number of rows and Ny number of columns. This matrix of C cells forms a radiating aperture of the transmitter 100 array at the input plane Pin. The matrix of C cells can have dimensions Nx * X / 2 and Ny * X / 2. The transmitter 100 array illustrated in [Fig. 4A], for example, is formed of Nx = 7 rows and Ny = 7 columns of C cells.

[0114] According to one example, the C cells can be arranged in a matrix arrangement, which has a pitch X / 2 = 14.3 mm. The portions of metallic film 2 of the C cells forming the matrix extend continuously between neighboring C cells in the matrix. Inside the input plane Pin, the first metallic wafers 1 of all the C cells of the transmitting array 100 can be oriented so that their respective feed segments 13 are all parallel, as illustrated in [Fig. 4A]. Parallel to the output plane Pout, the second metallic wafers 3 of all the C cells of the transmitting array 100 can also be oriented so that their respective feed segments 33 are all parallel.

[0115] In this C-cell matrix, each C-cell of the transmitting array 100 is preferably supplied with a voltage independent of the other C-cells in the array. Thus, by applying a particular voltage distribution to the different C-cells of the radiating aperture, a reconfigurable active phase shift distribution can be obtained. This allows manipulation of the wavefront of the incident radiation Rin. For example, the re-emitted radiation beam Rout can exhibit a higher gain at the aperture output compared to the incident radiation Rin during beam formation. The direction of the maximum re-emitted radiation beam Rout can be redirected, enabling the scanning of the re-emitted radiation beam.

[0116] A 100-cell C-transmitter network comprising two active components 15a, 15b enables a phase distribution produced by the active control of the polarization states of the active components 15a, 15b of each C-cell, known as a "1-bit" distribution. This distribution is designated "1-bit" because only two phase states are used, 0° and 180°. The use of a "1-bit" configuration is a compromise between the network's openness efficiency, the network's manufacturing complexity, and the reliability of the final product.

[0117] Another variant, not shown, of a 2-bit transmitter network is possible by introducing two pairs of active components 15a, 15b. This allows for the generation of four phase states, which further reduces the phase error. However, the presence of two additional active components induces higher insertion losses due to the parasitic resistance of these components, and increases the manufacturing complexity of the transmitter network.

[0118] In order to correct 1-bit distributions, another approach is possible, called "pseudo 2-bit", as described below.

[0119] As illustrated in [Fig. 4B], according to another example, the C cells of the array can be oriented such that the respective feed segments 33 of two juxtaposed C cells form an angle α. These two neighboring C cells produce respective contributions to the Rout radiation exhibiting a passive phase shift between them equal to α. This phase shift arises from the equivalence between a rotation of the electric field and a phase lag for circular polarization. It is then possible to select the respective orientations of the second metal plates 3 of all the C cells of the transmitting array 100, parallel to the output plane Pout, in order to obtain a beamforming effect for the re-emission radiation Rout.A person skilled in the art will be able to determine, through numerical simulations, an appropriate distribution of angle α values ​​in the matrix of the transmitting array 100, in order to reduce or adapt a divergence of the re-emitted radiation beam Rout. Figure 4B symbolically shows a distribution of variable angle α values ​​in a portion of the transmitting array 100. This phase shift is considered passive, because once the phase distribution is imprinted on the array, it is no longer possible to modify it to change the direction of the main beam.

[0120] This passive phase distribution at the second and / or third metal plates of the transmitting array can thus be used, within a special configuration of the transmitting array, to generate a pseudo 2-bit phase correction, thereby widening the angular range of pointing at low ellipticity and thus widening the field of view of the array. This configuration is still a correction of the "1-bit" configuration, but the multi-state passive phase distribution at the second 3rd and / or third 4th metal plates improves the performance of the transmitting array, particularly in pointing the Rout* re-emission radiation beam.

[0121] Figures 5A and 5B illustrate examples of 1-bit and 2-bit phase distributions. Figure 5A illustrates an example of a 1-bit distribution of active phases at the radiating aperture or the input plane Pin, obtained by controlling the phase states of the active components 15a, 15b of each cell C of the transmitting network 100 independently of the others. This distribution is shown in a two-dimensional (2D) plane along a first position on the ordinate axis 301 expressed in millimeters, and a second position on the abscissa axis 302 expressed in millimeters. This 1-bit distribution of active phases exhibits two phase states 401 and 402 corresponding respectively to the 0° and 180° phases. of the two active components 15a, 15b, or PIN diodes. These phase states 401 and 402, correspond to DC voltages of -5 V and +5 V applied across the terminals of the PIN diodes.

[0122] Figure 5B illustrates an example of a pseudo 2-bit passive phase distribution at the output plane Pout, obtained by the relative rotations of the second metal plates 3 of the cells C of the transmitter network. This pseudo 2-bit passive phase distribution exhibits discrete phase states 501, 502, 503, and 504 corresponding respectively to the 0°, 90°, 180°, and 270° phases corresponding to the values ​​of angles α. This pseudo 2-bit distribution is an example of a correction to the corresponding 1-bit distribution illustrated in Figure 5A.

[0123] As illustrated in [Fig. 0A], the transmitting array 100 can be used with a radiation source 200 to constitute a radio transmitting antenna 300, referred to as a transmitting array antenna. The source 200 can be of the horn type, which produces the radiation Rin in the X-band, with a center transmission frequency of 10.5 GHz. Such a source 200 produces the radiation Rin with a linear electric field polarization parallel to the x-axis, and with a nominal gain of 15.5 dBi, being effective throughout the entire 8 GHz - 12 GHz transmission spectral range. Typically, the nominal gain of a radio emission source is understood to be the value expressed in decibels (dB) of the ratio between the power emitted by this source in its main direction of emission and the power value that would be produced in this direction by an isotropic emission source, for the same total power value emitted.The z-axis designates the main emission direction of the source 200. The transmitting array 100 is then arranged perpendicular to the z-axis, at a distance D = 214 mm from the emission focus of the source 200, and is oriented around the z-axis so that the feed segments 13 are all parallel to the x-axis. In addition, the transmitting array 100 is rotated so that the source 200 is on the side of the first metal plates 1.

[0124] The distribution of bias voltages on each cell C is achieved by the presence of the feed lines 52 in the feed metal level 5. Each line is connected on one end to the first metal plate 1 via printed capacitors, and on the other end to a connector allowing the antenna to be connected by cables to a computer controlling the radiating system known as the "back-end," corresponding to a rear section. This back-end system allows the digital command to be sent to reconfigure the antenna pattern according to user needs. The routing (tracing of the feed lines 52) can be carried out exclusively on the feed metal level 5, or it can be divided between the feed metal level 5 and the first metal plate 1, depending on the spacing constraints between the cells C of the array. The routing on The metallic power supply level 5 is preferable to reduce coupling between DC and RF currents. In particular, it is preferable to ensure that each cell is controlled independently, i.e., that there is no electrical connection between two lines 52 of two different C cells. This ensures complete control over the active phases of the radiating aperture, allowing for complete 2D formation and scanning.

[0125] According to an exemplary embodiment of a transmitting array antenna 300, the transmitting array 100 may have a square perimeter in the xy plane with sides of 199.85 mm, and comprise 14 x 14 C cells juxtaposed in a matrix arrangement parallel to the x and y axes. These dimensions correspond to the individual size of the C cells of 14.275 mm x 14.275 mm, i.e., a matrix pitch equal to X / 2 for the transmit frequency of 10.5 GHz. The pattern of the second metal plates 3 of the transmitting array 100 is selected to produce the re-emitted radiation Rout with left-hand circular polarization. According to this example, the source 200 is of the horn type and emits Rin radiation in a frequency range between 8 GHz and 12 GHz, with a gain of approximately 15.4 dB. Rin radiation exhibits horizontal linear polarization.The reconfigurability of this transmitter network 100, according to this example, allows a maximum pointing error of the order of ±60° in two planes perpendicular to each other and perpendicular to the output plane Pout. .

[0126] The maximum gain of such a 100 transmitting array can be on the order of 21 dB at the center frequency, a value that is +6.5 dB higher than that of the primary source. Furthermore, for a so-called "broadside" pointing (corresponding to a pointing in the direction perpendicular to Pout), a left-handed circular polarization level at the output of this 100 transmitting array can be more than 26 dB higher than the right-handed circular polarization level, which confirms a high level of circular polarization purity. The "broadside" ellipticity ratio of the re-emitted Rout radiation is on the order of 0.86 dB at the transmission frequency of 10.5 GHz, which demonstrates the high purity of the left-handed circular polarization in this re-emitted Rout radiation. Finally, the 100 transmitting array antenna has the following additional characteristics: - a bandwidth Af / f at -1 dB gain: 13%, corresponding to the bandwidth Af = 1.3 GHz for the transmitting antenna 300 to transmitting array 100, - a bandwidth with an ellipticity rate of less than 3 dB: 12%, - a ratio of the directivity of the transmitting antenna 300 to the transmitting array to the maximum theoretical directivity that can be obtained with the same antenna surface, called aperture efficiency: 22.83%, and - a ratio of the power that is actually radiated by the 300 transmitting array antenna to the supply power of the 200 source, called power efficiency: 58%.

[0127] Another transmitting network has been implemented according to the present invention, sized for use within the Ka band, with a center frequency value of 30 GHz. Such a transmitting network 100 may have the following characteristics: - a horn-type 200 source, emitting Rin radiation in a frequency range between 26 GHz and 40 GHz, with a gain of approximately 15.5 dB, - a focal distance between the primary source and the radiating aperture of approximately 100 mm, - radiating aperture dimensions of approximately 100 mm x 100 mm for 20x20 cells, - a central frequency: 27 GHz, - an input polarization of the horizontal linear radiation Rin, - a polarization at the output of the re-emitted radiation Rout, left circular, - a maximum gain of approximately 22 dB at the center frequency, a value that is +7.5 dB higher than the primary source, - an ellipticity rate of the re-emitted radiation Rout of the order of 0.8 dB at the central emission frequency, - a bandwidth Af / f at -1 dB gain: between 15% and 20%, corresponding to a bandwidth Af equal to 4 GHz and 5.4 GHz, - a bandwidth in ellipticity rate less than 3 dB: greater than 20% - an opening efficiency of the order of 21.5%, and - a power efficiency of the order of 58%.

[0128] Thus, according to this example of a 100 transmitting network operating in the Ka band, high efficiency can be achieved with the reconfigurable C cell, as well as very wide bandwidths and very high polarization purity. A wide bandwidth and a wide pointing angle range can be targeted to meet the needs of 5th generation telecom applications, such as satellite links in LEO orbit, and 5G front-end and backhaul (point-to-point and point-to-multipoint links).

[0129] Finally, as illustrated in [Fig.6B], a transmitting network 100 which conforms to the invention can also be used to constitute a radio receiving antenna. The receiving antenna with a transmitting array is generally designated by the reference 500. In addition to the transmitting array 100, the receiving antenna 500 includes a radiation detector 400, which is located on the side of the transmitting array 100 that has the first metal plates 1. In the receiving antenna 500, the transmitting array 100 operates in the reverse direction of that described previously: external circularly polarized radiation Rext, incident on the transmitting array 100 on the side of the second metal plates 3, is absorbed by these plates when its polarization direction is appropriate. The electrical currents produced by this absorption are transmitted through the first connections 81 to the first metal plates 1, which then emit receiving radiation Rrecep towards the detector 400.The transmitting array 100 is selected to have a pattern of its first metal plates 1 that is compatible with a polarization state required by the detector 400. For example, the detector 400 may require the receive radiation RreCeP to have a suitably oriented linear polarization to provide optimal detection efficiency. In particular, the detector 400 may consist of a horn antenna used for reception. For such a receive antenna with a transmitting array 500, the beamforming function of the transmitting array 100 allows the receive radiation Rrecep to converge onto the detector 400.

[0130] A reconfigurable 100 transmitter network according to the invention allows for pointing in the two principal planes (E and H). Cell C of this network enables a wide-gain bandwidth while maintaining a very low ellipticity rate for a bandwidth of 12%. Furthermore, a fairly high gain level can be achieved with this 100 transmitter network. An improvement in bandwidth and aperture efficiency is obtained compared to state-of-the-art networks. The invention is particularly relevant for ground stations using the new LEO communication bands in the Ku / Ka band, as well as for services such as communication with high-altitude platforms (HAPs).Other applications are also conceivable, such as automotive radar applications with an adaptation of the TA structure to reduce the antenna profile, for example by using a configuration known as a "Folded Transmitarray" (FTA). Furthermore, the network architecture according to the invention is simpler in design (only one feed line per cell), and therefore less expensive. In particular, in the Ka band, it covers the entire FR2 band (24.5 GHz - 29.5 GHz) for 5th generation telecom applications.

[0131] It is understood that the invention can be reproduced by modifying secondary aspects of the embodiments described in detail above, while retaining at least some of the advantages mentioned. In particular, all the numerical values ​​cited are for illustrative purposes only and may be changed depending on the application and the radio transmission band involved.

Claims

1. Demands Polarizing cell (C), configured to receive incident radiation (Rin) on a first side of the cell (C), and to produce, from the incident radiation (Rin), re-emission radiation (Rout) on a second side of the cell opposite to the first side, said cell (C), comprising: • a portion of a metallic film (2), which is configured to form a ground plane for the cell (C) and which is provided with a hole (20); • a first metallic plate (1), which is located on the first side of the cell (C) with respect to the portion of metallic film (2), which is parallel to said portion of metallic film (2) and electrically insulated from said portion of metallic film (2), and which is configured to absorb at least partially the incident radiation (Rin); • a second metallic plate (3), which is located on the second side of the cell (C) relative to the portion of metallic film (2), which is parallel to said portion of metallic film (2) and electrically insulated from said portion of metallic film (2), and which is configured to produce the re-emission radiation (Rout); and • a first electrical connection (81), which connects the first metal plate (1) to the second metal plate (3) by passing through the portion of metal film (2) via the hole (20), while being electrically insulated from said portion of metal film (2), the second metal plate (3) having a pattern which includes the following parts of the second metal plate (3): • a first peripheral portion (30), which is comprised between a first external edge (31) and a first circular internal edge (32), the first circular internal edge (32) delimiting a first internal pattern zone of the second metal plate (3), and the first electrical connection (81) terminating at the center of the first circular internal edge (32); and

2. • a first power supply segment (33), which radially connects the first circular inner edge (32) to the first electrical connection (81), in the internal pattern area, the cell (C) being characterized in that the first metal plate (1) comprises a switching element (15), said switching element (15) being configured to produce in a controlled manner a first active phase shift of the incident radiation (Rin), and in that the pattern of the second metal plate (3) further comprises the following other parts of the second metal plate, which are also in the internal pattern area: • a second feed segment (34), which terminates radially at the first circular inner edge (32) at an angle between 80° and 100° with the first feed segment (33), the angle being measured at the center of the first circular inner edge (32); and • an intermediate band (35), which connects the first power supply segment (33) at the level of the first electrical connection (81) to one end of the second power supply segment (34) opposite the first circular inner edge (32), so that the first (33) and second (34) supply segments produce a second passive phase shift, by transmitting to the first peripheral portion (30) the first and second electric currents, respectively, and the intermediate band (35) has a length such that the second electric current is delayed in phase quadrature with respect to the first electric current at the level of the first circular inner edge (32), when the incident radiation (Rin) has a wavelength value which belongs to a resonance band of the cell (C) to produce the re-emission radiation (Rout) from the incident radiation (Rin). Cell (C) according to the preceding claim, comprising a metallic feed level (5) located between the portion of metallic film (2) and the first metallic wafer (1), the level metallic power supply (5) being parallel to the portion of metallic film (2) and electrically isolated from the portion of metallic film (2), the metallic power supply level (5) being configured to supply the switching element (15) with an electric current through two second electrical connections (82) linking the metallic power supply level (5) to the first metallic wafer (1).

3. Cell (C) according to the preceding claim, wherein the two second electrical connections (82) are vias arranged along an axis, called cell axis (AA) perpendicular to the portion of metallic film (2), on either side of the switching element (15), such that the connections of said vias with the first metallic plate (1) are located in areas of the first metallic plate (1) where the electric field is substantially zero.

4. Cell (C) according to any one of the two preceding claims, wherein the metallic feed level (5) is separated from the metallic film portion (2) by a distance along an axis, called the cell axis (AA) perpendicular to the metallic film portion (2), of between 89 pm and 178 pm.

5. Cell (C) according to any one of the preceding claims, wherein the switching element (15) comprises at least two active components (15a, 15b), configured to exhibit opposite polarization states controlled by the electric current transmitted through the two second electrical connections (82).

6. Cell (C) according to the preceding claim, wherein the pattern of the first metal plate (1) comprises the following parts of the first metal plate (1): • a second peripheral portion (10), which is comprised between a second outer edge (11) and a second circular inner edge (12), the second circular inner edge (12) delimiting a second internal pattern area of ​​the first metal plate (1), and the first electrical connection (81) terminating at a center of this second circular inner edge (12); and • a third power supply segment (13) in the second internal pattern area of ​​the first metal plate (1), said third power supply segment (13) comprising a central portion in which the connection of the first electrical connection (81) with the first metal plate (1) is located, and two peripheral portions disposed on either side of the central portion, the two peripheral portions radially connecting, on either side of the central portion, the second circular inner edge (12) to the first electrical connection (81) and each of the two peripheral portions comprising one, different, of the at least two active components (15a, 15b), said third power segment (13) being configured to transmit to the at least two active components (15a, 15b) the electrical current transmitted by the two second electrical connections (82).

7. Cell (C) according to any one of the two preceding claims, wherein the at least two active components (15a, 15b) are taken from the following group of active components: PIN type diodes, Varactor type diodes, microelectromechanical systems (MEMS) and phase change materials (PCM).

8. Cell (C) according to any one of the preceding claims, wherein the second metal plate (3) comprises a conductive arm (36), the cell (C) further comprising a third electrical connection (83) linking the second metal plate (3) to the portion of metal film (2) through the conductive arm (36).

9. Cell (C) according to any one of the preceding claims, wherein the intermediate strip (35) has a connecting part (35a) and a curved part (35b), the connecting part connecting the first power segment (33) at the first electrical connection (81) to a first end of the curved part, and a second end of said curved part being connected to the end of the second power segment (34) opposite the first circular inner edge (32).

10. A cell (C) according to any one of the preceding claims, further comprising, on the second side of the cell (C) and on one side of the second metal plate (3) opposite the portion of metal film (2), a third metal plate (4) parallel to the portion of metal film (2), and which is insulated electrically of each of said portion of metallic film (2) and of the first (1) and second (3) metallic plates, the third metallic plate (4) having a shape with rotational symmetry around the cell axis (AA), which passes through the center of the first circular inner edge (32) of the second metallic plate (3) and which is perpendicular to the portion of metallic film (2).

11. A transmitting network (100) comprising a plurality of identical cells (C) according to any one of the preceding claims, juxtaposed such that the portions of metallic film (2) extend continuously between neighboring cells, to form a flat, perforated screen, the cells (C) being arranged such that the respective first metallic plates (1) of said cells (C) are all on the same side of the transmitting network (100), and the cells (C) being spaced parallel to the flat, perforated screen such that: the respective first metallic plates (1) are disjointed, the respective second metallic plates (3) are disjointed, the respective third metallic plates (4), when said third metallic plates (4) are present in the cells, are disjointed, and the respective metallic levels (5),when said metallic levels (5) are present in the cells (C), are also disjoint.

12. Transmitting network (100) according to the preceding claim, wherein the switching elements (15) of each of the plurality of cells (C) are electrically powered by supply voltages independently of each other.

13. Transmitter array (100) according to any one of the two preceding claims, wherein the respective first metal plates (1) of the cells (C) are all identically oriented within an input plane (Pin) which is parallel to the perforated planar screen, and wherein the respective second metal plates (3) of the cells (C) have variable orientations within another plane which is also parallel to the perforated planar screen, said variable orientations being adapted to produce a beamforming function for radiation which is re-emitted by the transmitter array.

14. Radio transmitting antenna (300) comprising: • a source (200), configured to produce electromagnetic radiation exhibiting a polarization state; • a transmitting network (100) according to claim 11, arranged opposite a radiation output of the source (200), a first face of the transmitting network (100) which is opposite the radiation output of the source (200) having the first metal plates (1), in which the patterns of the first metal plates (1) are configured to absorb the radiation produced by the source (200), as incident radiation (Rin) for each cell (C) of the transmitting network (100), according to the polarization state of said incident radiation (Rin) as produced by the source.

15. Radio receiving antenna (500) comprising: • a detector (400), configured to detect a receive radiation (RreCeP) exhibiting a polarization state prescribed for said detector (400); and • a transmitting network (100) according to claim 11, arranged opposite the detector (400), a first face of the transmitting network (100) which is opposite the detector (400) having the first metal plates (1), in which the pattern of the first metal plates (1) is adapted to the polarization state prescribed for the detector (400), so that when an external radiation (Rext) having a circular polarization allowing absorption of said external radiation (Rext) by the second metal plates (3) of the transmitting network (100), arrives on a second face of said transmitting network (100) opposite to the first face of the transmitting network (100), the first metal plates (1) re-emit towards the detector (400) the receiving radiation (RreCeP) having the polarization state prescribed for said detector.

16. A method for converting the polarization state, using a polarizing cell (C) according to any one of claims 1 to 10, of incident radiation (Rin) having a first polarization state, producing from the incident radiation (Rin) re-emission radiation (Rout) having a second polarization state, said method comprising: reception of incident radiation (Rin) on the first side of the cell (C); at least partial absorption of the incident radiation (Rin) by the first metal plate (1); a first active and controlled phase shift of the absorbed incident radiation (Rin), produced by the switching element (15); a production of re-emission radiation (Rout) by the second metallic plate (3), from the incident radiation (Rin), said production comprising: • a second passive phase shift produced by the first (33) and second (34) supply segments, during a transmission to the first peripheral portion (30) of the first and second electric currents, respectively, the second electric current being delayed in quadrature of phase with respect to the first electric current at the level of the first circular inner edge (32), when the incident radiation (Rin) has a wavelength value which belongs to a resonance band of the cell (C).