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

Abstract

The invention relates to a polarising cell (C) configured to receive radiation incident on a first side of the cell, and to produce, from the incident radiation, on a second side of the cell opposite the first side, re-emission radiation that exhibits circular polarisation. The cell comprises a switching element (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 network, in particular as a component of a radio transmitting antenna or of a radio receiving antenna. A beam-forming and beam-scanning function can be achieved by controlling the active phase shift in each cell of the transmitting array.

Description

[0001] Active polarizing cell, transmitting network and radio transmitting and receiving antennas

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the field of radio frequency electronic engineering, particularly the design of reconfigurable transmitting array antennas. Its applications are particularly advantageous in satellite communications, high-speed communications, including the 5G standard, and automotive radar.

[0004] STATE OF THE ART

[0005] Transmitting arrays are increasingly used to create 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 array antennas consist of multiple radiation sources that are out of phase with each other, instead of a single radiation source for each transmitting array antenna.

[0006] 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.

[0007] To achieve high communication efficiency between a linearly polarized transmitted radio antenna and a linearly polarized receiving antenna, the polarization directions of the two antennas must be identical or nearly identical. In other words, an angular alignment step is required between the two radio antennas around the transmission direction, which can be particularly problematic or difficult to implement in certain circumstances, such as satellite communications. The use of circularly polarized beam antennas overcomes this difficulty.

[0008] Furthermore, most transmitter arrays rely on the passive unit cell concept, meaning a cell whose transmission coefficient phase is fixed by its geometric structure and remains unchanged after manufacturing. These are referred to as fixed-beam transmitter arrays, whose radiation direction can only be modified by multi-source excitation or by moving the focal source. Both of these methods exhibit limited beam shifting due to the significant phase aberrations caused by passive phase correction. Although techniques exist to expand the angular coverage of passive transmitter arrays, these solutions have reduced aperture efficiency, slower beam shifting speeds due to limitations in the mechanical movement of the focal source, and higher maintenance costs due to the presence of constantly moving mechanical parts.

[0009] 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.

[0010] SUMMARY OF THE INVENTION

[0011] 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 metal film through the hole, while being electrically insulated from said portion of 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 included between a first external edge and a first circular internal edge, the first circular internal edge delimiting a first internal pattern area of ​​the second metal plate, and the first electrical connection ending at the level of a center of the first circular internal edge;and a first feed segment, which radially connects the first circular inner edge to the first electrical connection, in the inner 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 inner pattern area: a second feed segment, which radially terminates at the first circular inner edge at 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 segment at the first electrical connection to one end of the second power segment opposite the first circular inner edge, such that the first and second power 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 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.

[0012] The cell described above is a reconfigurable cell, combining both a polarizer and a phase shifter function. Indeed, the reconfigurable and active aspect of the cell is achieved through 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 in the switching element. The first active phase shift produced by the switching element can be electronically regulated, allowing for a controllable phase shift of either 0° or 180°.

[0013] As for the polarization conversion, this is achieved through the combined action of the first and second metal plates. Indeed, during operation of the polarizing cell of the invention, the first electrical connection transmits a variable electric current to the second metal plate, resulting from the absorption of incident radiation by the first metal plate. This electric current is then transmitted simultaneously to the first peripheral portion of the second metal plate, partly via the first power supply segment of the second metal plate, and partly via 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 supply segments, and due to the angle between the respective connections of these two 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 area of ​​the pattern. This rotating electric current then produces the re-emission radiation field with a circular polarization and a specific direction of rotation, and with a high level of purity compared to the other direction of rotation with circular polarization.

[0014] 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 with 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 with a specific linear polarization, the polarizing cell of the invention performs a function of converting this linear polarization into circular polarization.

[0015] Such a reconfigurable polarizing cell eliminates the need for potentially expensive external polarizers or phase shifters. This cell can be manufactured using any available technology, including printed circuit boards. Its cost, as well as that of a transmitter network composed of such cells, can therefore be low.

[0016] A second aspect of the invention relates to a transmitting network comprising a plurality of identical cells, juxtaposed with each other so that the portions of metallic film extend continuously between neighboring cells, to form a flat screen with holes, the cells being arranged so that the respective first metallic plates of said cells are all on one side of the transmitting network, and the cells being spaced parallel to the flat screen with holes so 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 said metallic levels are present in the cells, are also disjointed.

[0017] The transmitter array, based on reconfigurable, polarizing unit cells, enables dynamic beam formation and scanning by controlling the polarization of the active components of the array. This allows for 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 array.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%.

[0018] A third aspect of the invention relates to a radio transmitting antenna comprising: a source, configured to produce electromagnetic radiation having a polarization state; a transmitting array, disposed opposite a radiation output of the source, a first face of the transmitting array 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 array, in accordance with the polarization state of said incident radiation as produced by the source.

[0019] A fourth aspect of the invention relates to a radio receiving antenna comprising: a detector, configured to detect a receiving radiation having a polarization state prescribed for said detector; and a transmitting array, disposed opposite the detector, a first face of the transmitting array which is opposite the detector having the first metal plates, in which the pattern of the first metal plates is adapted to the polarization state prescribed for the detector, so that when an 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 receiving radiation having the polarization state prescribed for said detector.

[0020] 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 a re-emission radiation having a second polarization state, said method comprising: receiving the incident radiation on the first side of the cell; at least partial absorption of the incident radiation by the first metal 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: o 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 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.;

[0021] BRIEF DESCRIPTION OF THE FIGURES

[0022] 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:

[0023] Figure 1 schematically illustrates a cross-sectional view of a polarizing cell according to an example embodiment.

[0024] Figure 2 schematically illustrates a perspective view of the metallic layers of the polarizing cell according to an example embodiment.

[0025] Figure 3A schematically illustrates a plan view of a portion of a metallic film of the polarizing cell according to an example of an embodiment.

[0026] Figure 3B schematically illustrates a plan view of a second metal plate of the polarizing cell according to an example of an embodiment.

[0027] Figure 3C schematically illustrates a plan view of a first metal plate of the polarizing cell according to an example of an embodiment.

[0028] Figure 3D schematically illustrates a plan view of a third metal plate of the polarizing cell according to an example of an embodiment.

[0029] Figure 3E schematically illustrates a plan view of a metallic power level for the polarizing cell according to an example embodiment.

[0030] Figure 4A schematically illustrates a view of an input plane of a transmitting network according to an example of an implementation.

[0031] Figure 4B schematically illustrates a view of part of another plane of the transmitting network according to an example of implementation.

[0032] Figure 5A schematically illustrates a "1-bit" phase distribution of a transmitting network, according to an example implementation.

[0033] Figure 5B schematically illustrates a "pseudo 2-bit" phase distribution of a transmitting network, according to an example implementation.

[0034] Figure 6A schematically illustrates a schematic view of a transmitting array antenna according to an example embodiment.

[0035] Figure 6B schematically illustrates a schematic view of a receiving antenna with a transmitting array according to an example of an embodiment.

[0036] The drawings are provided as examples and are not intended to limit the scope of the invention. They are schematic representations of the 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 various layers, patterns, and reliefs are not representative of reality.

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] Before proceeding with a detailed review of embodiments of the invention, optional features that may be used in combination or alternatively are listed below:

[0039] According to one example, the cell includes a metallic feed level situated 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 isolated 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 feed level to the first metallic wafer.

[0040] The metallic power supply delivers a direct current to the switching element of a cell. This metallic power supply 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.

[0041] As an example, the metallic feed level includes feed lines. These feed lines can exhibit high impedance due to their narrow width in a plane parallel to the metallic film portion.

[0042] As an example, the metallic power supply level includes metallic pads configured to electrically connect the power lines to the secondary electrical connections. These metallic pads, which form capacitors, can be manufactured by printing. This improves the decoupling between electromagnetic radiation and direct current.

[0043] 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.

[0044] The arrangement of the vias that connect 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.

[0045] According to one example, the metallic feed level is separated from the metallic film portion by a distance along an axis, called the cell axis perpendicular to the metallic film portion, between 89 pm and 178 pm.

[0046] This distance promotes the formation of a capacitance between the metal pads and the ground plane formed by the portion of metallic film, which helps to reduce the parasitic radiation that can be generated by the power lines.

[0047] 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.

[0048] By controlling the opposing polarization states of the active components in a cell, the initial phase shift of the incident radiation can be controlled. Specifically, 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, which allows the re-emitted radiation beam to be scanned.

[0049] According to one example, the pattern of the first metal plate includes 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 inner pattern area of ​​the first metal plate, and the first electrical connection ending 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 portion in which the connection of the first electrical connection with the first metal plate 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 internal edge to the first electrical connection and each of the two peripheral portions comprising one, different, of 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.

[0050] 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).

[0051] Varactor diodes (also known as variable reactor diodes or variable capacitance diodes) can be used for certain frequencies, such as the C-band. PIN diodes (Positive Intrinsic Negative) are commonly used in the design of reconfigurable transmitter arrays. These PIN diodes exhibit relatively low losses and are operable in a frequency range up to 50 GHz, allowing their use in millimeter-wave bands, such as the Ka-band. MCP materials can operate in the higher millimeter-wave frequencies (towards the 110 GHz band).

[0052] 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 metallic film through the conductive arm.

[0053] The conductive arm acts as a high-impedance quarter-wave transmission line, connecting the first metal plate to ground via the third electrical connection. The second metal plate is connected to the first, through which a direct current flows, potentially interfering with the RF currents. The second metal plate is circularly biased, and no zero electric field is present in its plane. The conductive arm creates an open circuit at its input, thus isolating the RF current from ground and preventing a short circuit. Only the currents intended to bias the active components can pass through the third electrical connection.

[0054] According to one example, the intermediate strip has a connecting part and a curved part, the connecting part connecting the first feed 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 feed segment opposite the first circular inner edge.

[0055] With this 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 electrical current it transmits to the second feed 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 overall 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 feed segments to the first peripheral portion of the second wafer.Preferably, the curved portion of the intermediate band can have an arc-shaped form within the pattern area, with an angular extent between 210° and 270°. Such an arc-shaped form of the curved portion also helps to reduce parasitic inductances that could degrade the operation of the polarizing cell.

[0056] As an example, the polarizing cell can be sized so that the resonance band of this cell is between 8 GHz (Gigahertz) and 12 GHz, corresponding to the X band.

[0057] As an example, the polarizing cell can be sized so that the resonance band of this cell is between 26.5 GHz and 40 GHz, corresponding to the Ka band.

[0058] However, the polarizing cell of the invention can alternatively be sized so that its resonance band is in other spectral areas assigned to listed types of radio communication.

[0059] 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.

[0060] Such a third metal plate is therefore electromagnetically coupled at a distance to the second metal plate. It allows the frequency band within which the polarizing cell is effective to be broadened.

[0061] According to one example, the third metal plate is an annular strip that is centered with respect to the cell axis.

[0062] According to one example, the third metal plate has dimensions adapted to widen the resonance band of the cell, compared to the cell when it lacks a third metal plate.

[0063] 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.

[0064] In the transmitting network, the cells can be arranged in a matrix, located at the intersections of rows and columns of a matrix. A matrix step, parallel to the rows and columns, can be approximately equal to half a wavelength value associated with a frequency value within the cell bandwidth. The relationship between a wavelength value, denoted Δ, and the associated frequency value, denoted f, is: Δ = C / f, where C is the speed of propagation of electromagnetic radiation in a vacuum.

[0065] As an example, in the transmitter network, the switching elements of each of the plurality of cells are electrically powered by supply voltages independently of each other.

[0066] These independent supply voltages between the cells of the transmitting network allow for complete control over the phase distribution within the radiating aperture of the network. Electronic beamforming and scanning can thus be performed in all 2D planes.

[0067] 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. Using a "1-bit" configuration is a compromise between network opening efficiency, network manufacturing complexity, and the reliability of the final product.

[0068] According to one example, in the transmitting array, the respective first metal plates of the cells are all identically oriented within an input plane that is parallel to the perforated planar screen, and in which the respective second metal plates of the cells have variable orientations within another plane that is also parallel to the perforated planar screen, said variable orientations being adapted to produce a beamforming function for radiation that is re-emitted by the transmitting array.

[0069] 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. Therefore, an appropriate selection of the respective orientations of the second metal plates of all the cells in this transmitting array 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 beam's secondary lobes.

[0070] This passive phase distribution at the second and / or third metal plates of the transmitting array can be used in a special configuration to generate a so-called "pseudo 2-bit" phase correction. This widens the angular range of pointing at low ellipticity and thus expands the array's field of view. While this configuration is still a correction of the "1-bit" configuration, the multi-state distribution of passive phase at the second and / or third metal plates improves the transmitting array's performance, particularly in pointing the re-emission radiation beam.

[0071] 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.

[0072] A substrate is understood to be a layer based on a species A, a substrate is a layer comprising only that species A, or that species A and possibly other species.

[0073] A parameter that is "approximately equal to / greater than / less than" a given value means that the parameter is equal to / greater than / less than the given value, within ±10% of that value. A parameter that is "approximately between" two given values ​​means that the parameter is at least equal to the smaller of the two given values, within ±10% of that value, and at most equal to the larger of the two given values, within ±10% of that value.

[0074] 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.

[0075] The steps of the process are understood in the broad sense of carrying out 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.

[0076] Furthermore, the term "step" does not necessarily imply that the actions carried out during a step are simultaneous or immediately successive. Some actions in a first step may 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 refer to unitary actions that are inseparable in time and in the sequence of phases of the process.

[0077] A polarizing cell C is now described with reference to figures 1 to 3E, according to an example of an embodiment.

[0078] As illustrated in Figure 1, the polarizing cell C comprises a first metallic plate 1 supported by a face of a first dielectric layer 50 which is opposite an entrance plane Pj nof cell C. Cell C further comprises a portion of metallic film 2 carried by a face of a second dielectric layer 60 which is opposite the entrance plane P in 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 it. The second metal plate 3 is carried by the other face of the second layer 60 that is opposite an exit plane P ou t of cell C, opposite the entry plane P in .

[0079] Cell C is configured to receive incident radiation Rj n on its entry plan P in , and to produce, from the incident radiation R in , a re-emission radiation R out from its exit plan P ou t.

[0080] 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 Rj n .

[0081] The cell C may further comprise a third metallic plate 4, carried by a third dielectric layer 70, on a face of the third dielectric layer 70 which is opposite the exit plane P ou t. 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.

[0082] The cell C may also include a metallic power supply level 5, carried on the other side of the first dielectric layer 50 which is opposite the output plane P out. The metallic feed level 5 is located between the portion of metallic film 2 and the first metallic wafer 1. The metallic feed level 5 is preferably parallel to the portion of metallic film 2 and electrically isolated from the portion of metallic film 2.

[0083] The first, second, and third dielectric layers 50, 60, 70 can be joined together by a first 56 and a second 67 assembly layer, commonly called a pre-preg. The dielectric layers, assembly layers, and metallic layers together form a stack of superimposed layers along an axis, called the cell axis AA, which is preferably perpendicular to the metallic film portion 2 and to the entrance planes Pj n and output P ou t.

[0084] The metal plates 1, 3, and 4 may have thicknesses of approximately 43 µm, 43 µm, and 35 µm, respectively. 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.

[0085] The polarizing cell C is preferably sized to operate within the X band, with a central bandwidth wavelength, denoted A, 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 Pj planes. n and P ou t, with sides equal to approximately A / 2 = 14.3 mm.

[0086] The portion of metallic film 2 forms a ground plane for cell C and is provided with a hole 20. The first metallic plate 1 is configured to absorb at least partially the incident radiation Rj n The second metal plate is configured to produce the re-emission radiation R ou t.

[0087] Figure 2 illustrates a three-dimensional view of cell C, in which the dielectric and assembly layers are hidden. Only the metallic layers are visible in Figure 2.

[0088] 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 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 may preferably be a via. The via may be made of a copper-based alloy and have an outer radius of 0.15 mm.

[0089] 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 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.

[0090] 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.

[0091] 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.

[0092] The geometries of the different metallic layers of cell C are now described with reference to figures 3A to 3E.

[0093] As illustrated in Figure 3A, the portion of metallic film 2 extends in a principal extension plane of cell C parallel to the planes Pj n and P ou t. This extension of the metallic film portion 2 is continuous except at the hole 20, which is preferably circular and centered on the axis AA. The hole 20 ensures electrical insulation of the metallic film portion 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.

[0094] As illustrated in Figure 3B, the second metallic plate 3, which is adapted to produce the re-emission radiation R out with circular polarization, also presents a pattern. This pattern of the second metal plate 3 comprises a first peripheral portion 30, continuous between a first outer edge 31 which is preferably square, and a first inner circular 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.

[0095] 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°.

[0096] The intermediate strip 35 connects the 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.

[0097] The first outer edge 31 of the second metal plate 3 has dimensions L pa tch3 and W pa tch3. Dimensions L patC h3 and W patCh3 are preferably 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 R cy i3, which is preferably equal to 2 mm. The first power supply segment 33 of the second metal plate 3 has a width Wij ne 3, 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 W s tn P 3, which is preferably equal to 0.43 mm.

[0098] As illustrated in Figure 3B, the second metal plate 3 may, in one example, include a conductive arm 36. According to this example, 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 cell AA, as illustrated in Figure 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 ±V œ This voltage ±V CC is preferably applied by a single power line. Therefore, the second metal plate 3 is advantageously referenced to the ground plane formed by the portion of metal film 2.

[0099] 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 current. Since the second metal plate 3 is circularly biased, there is no zero electric field 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 and 15b can pass through the third electrical connection 83.This conducting arm 36 is therefore optimized to improve the radiating system, taking into account the DC biasing circuit.

[0100] As illustrated in Figure 3C, the first metallic plate 1, which is adapted when the incident radiation Rj n It has a linear polarization and presents a pattern. This pattern of the first metal plate 1 includes 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 zone 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.

[0101] 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 comprises a central portion in which the connection of the first electrical connection 81 to the first metal plate 1 is located, as illustrated in Figure 3C. The third power supply segment 13 further comprises 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 passed to the two active components 15a, 15b, in order to bias them under direct current.

[0102] The active components 15a and 15b of the switching element 15 are preferably connected in an antiparallel configuration. This polarizes them with voltages of opposite signs, allowing their polarization states to be controlled by a single supply line. This control of the polarization states of the active components 15a and 15b enables electronic control of the transmission phase of cell C.

[0103] The active components 15a and 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°.

[0104] Other types of active components 15a, 15b can be used, such as Varactor diodes (also known as variable reactor diodes or variable capacitance 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 range (around the 110 GHz band).

[0105] Commercially available PIN diodes manufactured for frequencies up to 50 GHz are available. These PIN diodes allow their use in millimeter-wave bands, such as the Ka-band. Furthermore, biasing PIN diodes is relatively simple compared to biasing MEMS components. As illustrated in Figure 3C, the second outer edge 11 of the first metal wafer 1 has dimensions L pa tchi and W patC Hi. The dimensions L patChi and Wpatchi are preferably 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 R cy n, 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 Rj n when this incident radiation has a linear polarization of its electric field which is parallel to the longitudinal extension direction of the third feed segment 13.

[0106] As illustrated in Figure 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. Preferably, the two edges 41 and 42 are centered on the AA axis. The third metal plate 4 is electrically isolated from all other metal layers of cell C. Its effect on the operation of cell C results from long-range electromagnetic coupling between the second metal plate 3 and the third metal plate 4. The circular outer edge 41 and the circular inner edge 42 have radii Rcyl_ext4 and Rcyl_int4, respectively. These radii are two dimensional parameters that can be adjusted to control the widening 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.

[0107] As illustrated in Figure 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.

[0108] The metal feed level 5 may further include metal studs 51 arranged on either side of the axis of cell AA, in the plane of the metal feed level 5, as illustrated in Figure 2. These metal studs 51 preferably have a rectangular shape. They allow the power supply lines 52 to be electrically connected to the second electrical connections 82. The connections of the second electrical connections 82 to the metal studs 51 may preferably be located at the center of the metal studs 51.

[0109] These metallic 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 metallic pads 51 and the ground plane of the metallic film portion 2. The latter is separated from the metallic 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 thin enough to bring the metallic film portion 2 closer to the metallic feed layer 5, thus promoting capacitor formation and reducing parasitic radiation from the feed lines 52. The face of the metallic film portion 2 that faces the plane P in , is separated from the surface of the metal studs 51 which is opposite P out, of a distance d25 taken along the axis of cell AA. The choice of the distance d25 depends on the specifications of cell C, and can be between 89 pm and 178 pm.

[0110] This cell C enables the conversion function of the polarization state of the incident radiation Rj. n by producing re-emission radiation R ou t exhibiting a polarization state different from that of the incident radiation Rj n , according to the process described below. The process for converting the polarization state by cell C may include a step of receiving the incident radiation Rj n on the first metal plate 1, at the level of the entry plane P in This incident radiation Rj nThe 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, in particular that of the pattern.

[0111] The process also includes a first active and controlled phase shift of the incident radiation Rj n absorbed, 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 process also includes the production of re-emission radiation Rout by the second metal plate 3, from the incident radiation Rj n This stage of production of re-emission radiation R out includes a second passive phase shift produced by the first 33 and second 34 supply segments. This second phase shift is produced during transmission to the first peripheral portion 30 of the first and second electric currents, respectively. The second electric current is phase-quadrature delayed relative to the first electric current at the first circular inner edge 32, particularly when the incident radiation Rin has a wavelength value that belongs to a resonance band of cell C.

[0112] Indeed, when cell C receives the incident radiation Rj n on the first metal plate 1, in the entry plane P in , this Rj radiation n induces electric currents inside the first metal plate 1, which cause at least partial absorption of the radiation power Rj nFor the pattern of the first metal plate 1 described above, this absorption is maximum when the incident radiation Rj n is linearly polarized with its electric field parallel to the longitudinal direction of the third feed segment 13. The portion of metallic film 2 produces a screening effect for a residual part of the incident radiation Rj n which was not absorbed by the first metal plate 1. To improve 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 electrical currents that were generated by the incident radiation Rj n 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.

[0113] Through an electrical process inverse to that which occurred in the first metal plate 1, the electric currents arriving at plate 3 via the first electrical connection 81 are transmitted to its peripheral portion 30 by each of the supply segments 33 and 34. The portion of these electric currents transmitted by the supply segment 33 produces a component of the re-emission radiation R ou t which has a linear polarization parallel to this feed segment 33. Simultaneously, the other part of the electric currents, transmitted by the feed segment 34, produces another component of the re-emission radiation Rout which has a polarization parallel to this other feed segment 34.

[0114] The intermediate band 35 is designed to have a total length that produces a transmission delay of one quadrature of phase for the electrical currents it transmits. This total length can be easily adjusted by selecting the angular orientation of the connecting portion 35a relative to the longitudinal direction of the feed segment 33, and by adapting accordingly the angular length of the curved portion 35b to join the feed segment 34. Since the two feed segments 33 and 34 are perpendicular (0=90°), and the intermediate band 35 delivers to the peripheral portion 30, via the feed segment 34, the portion of the electrical currents it transmits with a delay of one quadrature relative to the portion of the electrical currents transmitted by the feed segment 33, the two components of the re-emission radiation R out combine to produce this re-emission radiation with circular polarization.

[0115] Wij widths ne 3 and W s sorting P Three layers can be selected so that the electrical currents transmitted by the power supply segments 33 and 34 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 dynamically controlled. Once cell C is manufactured, this second passive phase shift remains unchanged.

[0116] A 100 transmitting network comprising a plurality of C cells, is now described with reference to Figures 4A to 5B.

[0117] As illustrated in Figure 4A, the transmitter network 100 can be fabricated by placing a large number of C cells, as described previously, on large printed circuit boards. These C cells are arranged side by side in a plane parallel to plane P. in , so as to form a matrix of cells C with a number N x of lines and a number N y of columns. This cell matrix C forms a radiating opening of the transmitting network 100 at the level of the input plane Pj n The cell matrix C can have N dimensions x *At / 2 and N y *A / 2. The 100 transmitter network illustrated in Figure 4A, for example, is formed of N x =7 lines and N y =7 columns of cells C.

[0118] As an example, the C cells can be arranged in a matrix pattern with a pitch A / 2 = 14.3 mm. The metallic film portions 2 of the C cells forming the matrix extend continuously between neighboring C cells in the matrix. Inside the entry plane P in The first metal plates 1 of all the cells C of the transmitter network 100 can be oriented so that their respective feed segments 13 are all parallel, as illustrated in Figure 4A. Parallel to the output plane P ou t, the second metal plates 3 of all the cells C of the transmitter network 100 can also be oriented so that their respective supply segments 33 are all parallel.

[0119] 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 specific 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 Rj n For example, the re-emitted radiation beam R ou t can exhibit a higher gain at the aperture output compared to the incident radiation Rj n during beam formation. The direction of the re-emitted radiation beam R ou t maximum, can be redirected, which allows the scanning of the re-emitted radiation beam.

[0120] A 100-cell C-type transmitter network comprising two active components 15a, 15b, enables a phase distribution produced by actively controlling the polarization states of the active components 15a, 15b of each C-type 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 represents a compromise between the network's openness efficiency, the network's manufacturing complexity, and the reliability of the final product.

[0121] 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, resulting in a further reduction of the phase error. However, the presence of two additional active components leads to higher insertion losses due to their parasitic resistance, and increases the manufacturing complexity of the transmitter network.

[0122] To correct 1-bit distributions, another approach is possible, called "pseudo 2-bit", as described below.

[0123] As illustrated in Figure 4B, in another example, the C cells of the matrix 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 radiation R out exhibiting a passive phase shift between them equal to a. This phase shift arises from the equivalence between a rotation of the electric field and a phase delay for circular polarization. It is then possible to select the respective orientations of the second metal plates 3 of all the cells C of the transmitting network 100, parallel to the output plane P ou t, in order to obtain a beamforming effect for the re-emission radiation R ou t. A person skilled in the art will be able to determine, through numerical simulations, an appropriate distribution of angle values ​​α in the matrix of the transmitting network 100, in order to reduce or adapt a divergence of the beam of the re-emitted radiation R out. Figure 4B symbolically shows a distribution of variable values ​​of angle a in a part of the transmitting network 100. This phase shift is considered passive, because once the phase distribution is printed on the network, it is no longer possible to modify it to change the direction of the main beam.

[0124] This passive phase distribution at the second and / or third metal plates of the transmitting array can be used in a special configuration of the transmitting array to generate a pseudo 2-bit phase correction. This widens the angular range of pointing at low ellipticity and thus expands 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 and / or third metal plates improves the performance of the transmitting array, particularly in pointing the re-emission radiation beam R ou t.

[0125] 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 input plane P in This distribution was obtained by independently controlling the phase states of the active components 15a and 15b of each cell C in the transmitter network 100. This distribution is illustrated in a two-dimensional (2D) plane, with 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 and 15b, or PIN diodes. These phase states 401 and 402 correspond to DC voltages of -5 V and +5 V applied across the PIN diodes.

[0126] Figure 5B illustrates an example of a pseudo 2-bit passive phase distribution at the output plane P ou t, obtained by the relative rotations of the second metal plates 3 of the cells C of the transmitter network. This pseudo 2-bit distribution of passive phases exhibits discrete phase states 501, 502, 503, and 504 corresponding respectively to the phases 0°, 90°, 180°, and 270° corresponding to the values ​​of the angles a. This pseudo 2-bit distribution is an example of a correction to the corresponding 1-bit distribution illustrated in Figure 5A.

[0127] As illustrated in Figure 6A, the transmitting array 100 can be used with a radiation source 200 to form a radio transmitting antenna 300, known as a transmitting array antenna. The source 200 can be of the horn type, which produces the Rj radiation. nin the X band, with a center emission frequency of 10.5 GHz. Such a source produces 200 Rj radiation nwith a linear polarization of the electric field parallel to the x-axis, and with a nominal gain of 15.5 dBi, being effective throughout the entire 8 GHz - 12 GHz emission spectral range. Typically, the nominal gain of a radio emission source is defined as the value, expressed in decibels (dB), of the ratio between the power emitted by that source in its principal emission direction and the power that an isotropic emission source would produce in that direction, for the same total emitted power. The z-axis designates the principal 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 transmitter network 100 is rotated so that the source 200 is on the side of the first metal plates 1.

[0128] The distribution of bias voltages on each C cell is achieved by the presence of the feed lines 52 in the feed metal layer 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." This back-end system allows the digital command to be sent to reconfigure the antenna pattern according to user requirements. The routing (tracing of the feed lines 52) can be performed exclusively on the feed metal layer 5, or it can be divided between the feed metal layer 5 and the first metal plate 1, depending on the spacing constraints between the C cells of the array.Routing on the metallic feed 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 shaping and scanning.

[0129] According to an example of a transmitting array 300, the transmitting array 100 can have a square perimeter in the xy plane with sides of 199.85 mm, and comprise 14 x 14 juxtaposed C-cells 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 Å / 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 R ou t with left-hand circular polarization. According to this example, the source 200 is of the horn type, and emits Rj radiation n in a frequency range between 8 GHz and 12 GHz, with a gain of approximately 15.4 dB. The Rj radiation nexhibits horizontal linear polarization. The reconfigurability of this transmitter network 100 allows, in this example, a maximum pointing offset of approximately ±60° in two planes perpendicular to each other and perpendicular to the output plane P. ou t.

[0130] The maximum gain of such a 100 transmitter network 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 direction perpendicular to P) ou t), a left-handed circular polarization level at the output of this transmitting network 100 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 radiation R out is on the order of 0.86 dB at the emission frequency of 10.5 GHz, which shows the high purity of the left-handed circular polarization in this re-emitted radiation R ou t. Finally, the transmitting antenna with transmitter array 100 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 with transmitter array 100, a bandwidth in ellipticity ratio less than 3 dB: 12%, a ratio of the directivity of the transmitting antenna 300 with transmitter array to the maximum theoretical directivity that can be obtained with the same antenna area, called aperture efficiency: 22.83%, and a ratio of the power that is actually radiated by the transmitting antenna 300 with transmitter array to the feed power of the source 200, called power efficiency: 58%.

[0131] Another transmitting network has been implemented according to the present invention, sized for use within the Ka band, with a center frequency of 30 GHz. Such a transmitting network 100 may have the following characteristics: a horn-type source 200, emitting Rj radiation n 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 center frequency of 27 GHz, and an input polarization of the radiation Rj n horizontal linear, a polarization at the output of the re-emitted radiation R out, left circular, a maximum gain of approximately 22 dB at the center frequency, a value that is +7.5 dB higher than that of the primary source, an ellipticity ratio of the re-emitted radiation R ou t of the order of 0.8 dB at the center emission frequency, a bandwidth Af / f at -1 dB gain: between 15% and 20%, corresponding to the bandwidth Af equal to 4 GHz and 5.4 GHz, a bandwidth in ellipticity ratio 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%.

[0132] Thus, according to this example of a 100-channel Ka-band transmitting network, 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 5-channel telecom applications. èmegeneration, such as satellite links in LEO orbit, 5G front and backhauling (point-to-point and point-to-multipoint link).

[0133] Finally, as illustrated in Figure 6B, a transmitting array 100 according to the invention can also be used to constitute a radio receiving antenna. The receiving antenna with a transmitting array is designated collectively by the reference numeral 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 opposite way to that described previously: external radiation R ext, which is circularly polarized and incident on the transmitting network 100, on the side of the second metal plates 3, is absorbed by these plates when its polarization direction is appropriate. The electric currents produced by this absorption are transmitted through the first connections 81 to the first metal plates 1, which then emit a receiving radiation R re cep towards 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 detector 400. For example, detector 400 may require that the receive radiation R recep has a linearly polarized beam, properly oriented to provide optimal detection efficiency. In particular, detector 400 can be a horn antenna used for reception. For such a receiving antenna with a transmitting array 500, the beamforming function of the transmitting array 100 allows the receiving radiation R to converge re cep on detector 400.

[0134] A reconfigurable 100-channel transmitter network according to the invention enables pointing in both principal planes (E and H). Cell C of this network allows for a wide gain bandwidth while maintaining a very low ellipticity rate for a bandwidth of 12%. Furthermore, a relatively high gain level can be achieved with this 100-channel transmitter network. An improvement in bandwidth and openness 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." 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 telecom applications. ème generation.

[0135] It is understood that the invention can be reproduced by modifying minor 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

DEMANDS 1. Polarizing cell (C), configured to receive incident radiation (Rj n ) on one side of the cell (C), and to produce, from the incident radiation (Rin), re-emission radiation (R ou t) on a second side of the cell opposite 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) 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 absorb at least partially the incident radiation (Rj n ) ; • 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 (R ou t); 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 • 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 way controlled a first active phase shift of the incident radiation (Rj n), 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 first electrical connection (81) to one end of the second power supply segment (34) opposite the first circular inner edge (32), such that the first (33) and second (34) power supply segments produce a second passive phase shift, transmitting first and second electrical currents, respectively, to the first peripheral portion (30), and the intermediate band (35) has a length such that the second electrical current is delayed in quadrature phase with respect to the first electrical current at the first circular inner edge (32), when the incident radiation (Rj) n ) has a wavelength value that belongs to a cell resonance band (C) to produce re-emission radiation (R ou t) from the incident radiation (Rj n ).

2. 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 metallic feed level (5) being parallel to the portion of metallic film (2) and electrically isolated from the portion of metallic film (2), the metallic feed level (5) being configured to supply the switching element (15) with an electric current through two second electrical connections (82) linking the metallic feed 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 zone 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 internal 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 supply 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 linking 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. 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) which is opposite the portion of metal film (2), a third metal plate (4) which is parallel to the portion of metal film (2), and which is electrically insulated from each of said portion of metal film (2) and from the first (1) and second (3) metal plates, the third metal plate (4) having a shape with rotational symmetry about the cell axis (AA), which passes through the center of the first circular inner edge (32) of the second metal plate (3) and which is perpendicular to the portion of metal film (2).

11. A transmitting network (100) comprising a plurality of identical cells (C), each according to any one of the preceding claims, juxtaposed with each other such that the portions of metallic film (2) extend continuously between neighboring cells, to form a flat screen with holes, 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 screen with holes 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. Transmitter network (100) according to the preceding claim, wherein the switching elements (15) of each of the plurality of cells (C) are electrically supplied by supply voltages independently of each other.

13. Transmitter network (100) according to any one of the two preceding claims, wherein the respective first metal plates (1) of the cells (C) are all oriented identically 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 network.

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, disposed 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), wherein the patterns of the first metal plates (1) are configured to absorb the radiation produced by the source (200), as incident radiation (Rj n ) for each cell (C) of the transmitting network (100), according to the polarization state of said incident radiation (Rj n ) 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 array (100) according to claim 11, disposed opposite the detector (400), a first face of the transmitting array (100) opposite the detector (400) having the first metal plates (1), wherein the pattern of the first metal plates (1) is adapted to the polarization state prescribed for the detector (400), such that when external radiation (R ex t) exhibiting a circular polarization allowing absorption of said external radiation (R ext ) via the second metal plates (3) of the transmitting array (100), arriving on a second face of said transmitting array (100) opposite the first face of the transmitting array (100), the first metal plates (1) re-emit towards the detector (400) the received radiation (R re cep) exhibiting 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, by producing from the incident radiation (Rj n ) a re-emission radiation (R ou (t) exhibiting a second polarization state, said process comprising: • reception of incident radiation (Rj n ) on the first side of cell (C); • at least partial absorption of the incident radiation (Rj n) by the first metal plate (1); • a first active and controlled phase shift of the incident radiation (Rj n ) absorbed, produced by the switching element (15); • a production of re-emission radiation (R ou (t) by the second metallic plate (3), from the incident radiation (Rin), said production comprising: o 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 phase quadrature with respect to the first electric current at the level of the first circular inner edge (32), when the incident radiation (Rj) n ) has a wavelength value that belongs to a resonance band of the cell (C).

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