Transmitter array antenna

Abstract

The invention relates to an antenna: a first wall and a second wall facing the first wall, the surfaces of the first and second walls facing each other being at least partially reflective and defining a cavity between them; at least one lateral wall connecting the first and second walls and having an internal surface within the cavity that is at least partially reflective; the cavity being a resonant cavity; the antenna further comprising at least one electromagnetic source on one of the walls; at least one transmitting array carried by the second wall comprising at least two elementary cells, each comprising: a receiver within the cavity, a transmitter outside the cavity, and an interconnector transmitting the wave from the receiver to the transmitter; one of the elementary cells being configured so that the phase of the wave is modified before transmission. Figure for the abstract: Fig. 1

Description

Title of the invention: Transmitting array antenna Technical field

[0001] The invention relates to a transmitting array antenna. Prior art

[0002] Many applications require the use of directional and / or reconfigurable antennas. By "reconfigurable", it is understood that at least one characteristic of the antenna can be modified during its lifetime, after its manufacture. The modifiable characteristic(s) are generally the frequency response (in amplitude and phase), the radiation pattern, and the polarization. The reconfiguration of the frequency response covers different functionalities such as frequency switching, frequency tuning, bandwidth variation, phase shift, frequency filtering. The reconfiguration of the radiation pattern covers in particular depointing, beam opening typically defined at half-power, spatial filtering, beam or multi-beam formation.

[0003] Regarding the directivity of the radiation pattern, there are different types of directional antenna, including: - reflectors and lenses, - reflect-array antennas which return the beam to the source, - the transmit-array antennas which transmit the beam.

[0004] The advantages of transmitting array antennas include good energy efficiency, and being relatively simple, inexpensive, and compact, thanks in particular to the fact that the transmitting arrays can be produced using planar technology, generally on a printed circuit.

[0005] Transmitting array antennas are particularly advantageous for the following applications: - automotive radars for assistance and driving assistance in K band (between 18 and 27 GHz) and W band (between 75 and 110 GHz), - very high resolution imaging and monitoring systems in high millimeter or sub-millimeter bands, - short-range, high-speed communication systems, operating in particular in the K (between 18 and 27 GHz) and V (between 40 and 75 GHz) bands, - satellite internet in the Ka band (between 26.5 and 40 GHz), - satellite broadcasting in Ku band (between 12 GHz and 18 GHz), - applications associated with the X band (between 8 and 12 GHz), in particular space or meteorological applications.

[0006] These antennas generally comprise several elementary cells, in particular planar cells, each comprising a receiver receiving an electromagnetic field emitted by one or more sources, in particular a horn source or compact antenna array, a transmitter transmitting a modified signal to the outside of the antenna and an interconnector between the receiver and the transmitter. The modification of the signal is in particular a phase modification and / or an amplitude weighting of the signal.

[0007] Such transmitting array antennas have reduced efficiency due to the loss of energy not intercepted by the transmitting array (loss by "spill-over"), in particular towards the rear of the source, by reflection, and by the sides. In addition, they are bulky due to the significant distance required between the source and the elementary cells.

[0008] There is therefore a need to improve transmitting array antennas, in particular to improve efficiency and have a reduced footprint. Presentation of the invention

[0009] The invention aims to meet this need by an antenna comprising: - a first wall and - a second wall extending at least partially opposite the first wall, the surfaces of the first and second walls opposite each other being at least partially reflective of electromagnetic waves and defining a cavity between them, - at least one side wall of the cavity connecting the first and second walls together and having an internal surface of the cavity at least partially reflecting electromagnetic waves, the cavity being a resonant cavity of the electromagnetic wave, the antenna further comprising - at least one electromagnetic source carried by one of the first wall, the second wall and the side wall and being configured to emit an electromagnetic wave into the resonant cavity, - at least one transmitter network carried at least by the second wall, the transmitter network comprising at least two elementary cells, each elementary cell comprising: • an electromagnetic receiver extending into the resonant cavity, • an electromagnetic transmitter extending outside the cavity, • an interconnector configured to transmit an electromagnetic wave picked up by the electromagnetic receiver to the transmitter, at least one of the elementary cells being configured so that the phase of the wave emitted by the transmitter is modified relative to that of Fonde received by the receiver.

[0010] By "resonant cavity", we understand a space between the emission and transmission walls in which an electromagnetic wave having a frequency equal to or close to a resonant frequency of the resonant cavity enters into resonance in the cavity, that is to say that a standing electromagnetic wave having antinodes, Fonde amplitude peak zones, and nodes, wave amplitude well zones, is formed in the cavity. A resonant cavity has several resonant frequencies corresponding in particular to a resonant frequency of the impedance, a resonant frequency of the admittance, a resonant frequency corresponding to an adaptation of the cavity.

[0011] By "at least partially reflecting electromagnetic waves", it is understood that a portion of the electromagnetic waves is reflected back into the cavity by said wall. Preferably, the surfaces internal to the resonant cavity of the first wall, the second wall and / or the side wall(s) reflect at least 50%, better still at least 70%, even better still at least 80%, even better still at least 90% of the electromagnetic waves. The surfaces internal to the resonant cavity of the first wall, the second wall and / or the side wall(s) may be metallic, metallized, or comprise a surface layer made of a metamaterial or a material which is a mixture of metals and metamaterials.

[0012] In the following, the term “wave” will be used alone to designate an electromagnetic wave.

[0013] The presence of the resonant cavity makes it possible to reduce the size of the antenna by eliminating the necessary significant focal distance between the source and the transmitting network. Such a reduction in the distance between the source and the transmitting network also makes it possible to reduce lateral losses, which makes it possible to increase the quality of the emitted Foundry, in particular by the elementary cells present at the edges of the transmitting network. The use of the different walls to form the cavity also makes it possible to reduce losses from the rear and laterally, which further improves the transmission efficiency, in particular by reducing the “spillover” (part of the radiation which does not reach the elementary cells).

[0014] Such an antenna, by the presence of the different walls, also allows better protection of the antenna from the environment in terms of rigidity and performance. Finally, the different walls offer numerous possibilities for fixing the antenna or additional elements to the antenna, in particular sensors or additional devices.

[0015] The antenna may or may not be reconfigurable. Resonant cavity

[0016] Preferably, the first wall and the second wall are substantially planar.

[0017] Preferably, the first wall and the second wall are parallel to each other.

[0018] Preferably, the first wall and the second wall have identical contours. By "identical contours" we mean that the contours have an outline of the same shape and the same dimensions.

[0019] The first wall and the second wall may be circular, elliptical or polygonal, in particular rectangular, square or in the shape of a regular polygon.

[0020] The cavity may be cylindrical in shape, the first wall and the second wall forming the bases of the cylindrical shape and the side wall at least partially forming the side surface of the cylindrical shape.

[0021] The antenna may comprise at least two opposite side walls of the resonant cavity which at least partially reflect the wave.

[0022] The cavity may be entirely delimited by one or more side walls, the antenna comprising as many side walls as there are side edges of the cavity. Alternatively, at least one edge, better still two edges, of the resonant cavity are open, i.e. devoid of walls.

[0023] The surfaces internal to the resonant cavity of the first wall, the second wall and / or the side wall(s) may comprise one or more zones transparent to the wave or reduced wave reflection, in particular having a wave transmission greater than or equal to 50%, better still greater than or equal to 70%, even better still greater than or equal to 80%. The first wall, the second wall and / or the side wall(s) may comprise through openings, in particular the side wall(s) may comprise lateral openings, in particular slots. Preferably, the lateral openings and / or the transparent or reduced reflection zones extend over less than 50%, in particular less than 30%, better still less than 20%, of the surface of the corresponding wall.

[0024] The cavity may be entirely delimited by the first wall, the second wall and one or more side walls, all of these walls being solid over their entire surface, that is to say without opening.

[0025] Preferably, the antenna is configured so that more than 50%, more preferably more than 70%, of the wave remains in the cavity to form the resonant standing wave.

[0026] Preferably, the distance between the first wall and the second wall is between X and 100X, better between X and 10X, X being the wavelength of the waves emitted by the source.

[0027] Preferably, the resonant cavity is filled with an electromagnetically conductive medium, in particular a dielectric medium. The dielectric medium may be air or a dielectric substrate. The term "dielectric substrate" means a substrate made of a material having an electrical conductivity at 300 K of less than 108 S / cm. Source

[0028] The antenna may comprise a plurality of electromagnetic sources.

[0029] Preferably, the antenna comprises a plurality of electromagnetic sources carried by the same wall, in particular the first wall, the electromagnetic sources being spaced apart to form a spatial network of electromagnetic sources. The electromagnetic sources may be arranged on the wall in a matrix, in particular a square matrix. The electromagnetic sources may be equally distributed on the wall in the matrix.

[0030] The antenna may comprise at least two electromagnetic sources carried by different walls.

[0031] Preferably, the, part or all of the electromagnetic sources are carried by the first wall.

[0032] The electromagnetic source or the matrix of electromagnetic sources may or may not be centered on the wall which carries it.

[0033] In the case of a plurality of electromagnetic sources, the sources may be coupled together.

[0034] The electromagnetic source(s) may be configured to emit a wave at a frequency between 1 GHz and ITHz, preferably between 5 GHz and 100 GHz.

[0035] The source(s) may emit a wave into the cavity at a non-zero distance from the wall carrying them. In the case of a plurality of sources, two of the sources may emit a wave into the cavity at different distances from the wall carrying them.

[0036] Preferably, the electromagnetic source(s) comprise a patch-type antenna. Additionally or alternatively, they may each comprise a plunger extending into the resonant cavity transversely to the mean plane of the wall carrying it and a disk forming an excess thickness at the end of the plunger extending into the resonant cavity. The plunger may extend into the cavity over a length greater than or equal to 5 mm, better still greater than or equal to 10 mm, even better still greater than or equal to 15 mm.

[0037] The electromagnetic source(s) may have a central axis substantially orthogonal to the mean plane of the wall carrying it, in particular of the first wall and in particular of the transmitting network. In the case of sources carried by the first wall, the source(s) may be aligned with the center of the transmitting network. The matrix of sources may be centered on the first wall. Transmitter network

[0038] The transmitter network may comprise more than two elementary cells arranged on the second wall in a matrix according to rows and / or columns. Preferably, the rows and / or columns have at least four elementary cells.

[0039] Preferably, the matrix of elementary cells is a square matrix. The elementary cells may be equally distributed in the matrix. Alternatively, the elementary cells are not equally distributed and may form a pattern on the transmitter network.

[0040] Preferably, the transmitter network has an even number of rows and columns, the center of the second wall being devoid of elementary cells.

[0041] Preferably, the transmitter network is produced using planar technology, for example on a printed circuit board. In a preferred embodiment, the network can be produced using PCB (Printed Circuit Board) technology.

[0042] Preferably, the elementary cells are patch-type antennas. The transmitter network may comprise at least one conductive layer forming a matrix of conductive zones extending over the second wall, on the outer side of the latter, and a ground plane spaced from the conductive layer by a dielectric layer, the conductive zones forming the emitters of the elementary cells. The conductive zones may be discontinuous so that the emitters of the different elementary cells are isolated from each other. The elementary cells may each comprise a plunger extending from the corresponding conductive zone through the dielectric layer and into openings in the ground plane, the plungers extending into the resonant cavity transversely to the second wall. The plungers may comprise a disk forming an excess thickness at their ends extending into the resonant cavity.Such plungers are configured to receive the wave and transmit it to the transmitter. The end discs form the receivers and the plungers form the interconnectors. The plungers may extend into the cavity over a length greater than or equal to 5 mm, better still greater than or equal to 10 mm, even better greater than or equal to 15 mm.

[0043] The conductive zones may each comprise a slot, in particular a U-shaped slot.

[0044] Alternatively or additionally, the transmitter network comprises at least one additional conductive layer on the internal side of the second wall, the ground plane being spaced from the additional conductive layer by an additional dielectric layer, the receivers of the elementary cells being formed in the additional conductive layer, the ground plane comprising passage openings of the interconnector extending between the receiver and the transmitter. The additional conductive layer may be discontinuous so that the receivers of the different elementary cells are isolated from each other.

[0045] The interconnectors can be passive or active.

[0046] The second wall extending between the receiver and the transmitter may be single or multi-layer.

[0047] Preferably, the transmitter network comprises N configurations of distinct elementary cells, N being greater than or equal to 2. Preferably, the N configurations have different pairs of phase shifts and amplitude weightings. By “different pairs of phase shifts and amplitude weightings”, it is understood that each of the N configurations is associated with a phase shift and an amplitude weighting of the wave received by the receiver and that the N configurations are different from each other either by the phase shift, or by the amplitude weighting, or by both, the elementary cells of the same configuration all having the same phase shift and the same amplitude weighting. This makes it possible in particular to have a predetermined transmitted radiation pattern depending on the source by acting on the N configurations and the positioning of the elementary cells of the different configurations on the second wall.

[0048] At least two of the N configurations may have different amplitude weightings. The plungers of the elementary cells of said two configurations may extend in the cavity over different lengths.

[0049] At least two of the N configurations may have different phase shifts. The slits of the elementary cells of the two configurations may be oriented differently. At least two elementary cells may have slits forming an angle of 180° between them.

[0050] The transmitter network may comprise several cells of each configuration.

[0051] The phase shift and / or the amplitude weighting of each elementary cell can be controllable and the antenna can comprise a member for controlling the phase shift and / or the amplitude weighting of the elementary cells in groups and / or individually. This makes it possible to have a reconfigurable antenna in which the radiation pattern can be modified.

[0052] Preferably, the transmitter network is symmetrical with respect to at least one transverse plane, better still at least two transverse planes.

[0053] Preferably, for each of the N configurations, the cells are symmetrical with respect to at least one transverse plane, better still at least two transverse planes.

[0054] Preferably, the elementary cells of the transmitter network are positioned at a non-zero distance from the or all of the electromagnetic sources, in particular the disks of the elementary cells in the cavity are spaced from the or all of the electromagnetic sources. Preferably, the distance between the elementary cells, in particular the disks of the elementary cells in the cavity, and all of the electromagnetic sources is greater than or equal to X / 2, better still greater than or equal to X, X being the wavelength of the waves emitted by the source. Preferably, no elementary cell is arranged opposite the or one of the electromagnetic sources on the second wall.

[0055] Preferably, the receivers of the transmitter network are each configured to pick up the electromagnetic wave in resonance in the cavity in an area not corresponding to a stationary Fonde well in resonance in the cavity. The receivers of the transmitter network may each be configured to pick up the electromagnetic wave in resonance in the cavity in an area corresponding substantially to an antinode of the stationary wave in resonance in the cavity.

[0056] The plunger(s) of the source(s) and of the elementary cell(s) may extend into the cavity along distinct longitudinal axes parallel to each other. Brief description of the drawings

[0057] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This is purely illustrative and must be read in conjunction with the appended drawings in which:

[0058] [Fig-1] is a schematic cross-sectional representation of an example of an antenna according to the invention,

[0059] [Fig.2] is a schematic sectional representation of an antenna variant according to the invention,

[0060] [Fig.3] is a schematic sectional representation of an antenna variant according to the invention,

[0061] [Fig.4] is a schematic sectional representation of an antenna variant according to the invention,

[0062] [Fig.5] represents a section of the amplitude of a resonance wave in the cavity,

[0063] [Fig.6] is a schematic representation of an example of an elementary cell in top view, and

[0064] [Fig.7] is a schematic representation of an example transmitter network in top view. Description of the embodiments

[0065] The same elements have been designated by the same references in the various figures and, moreover, the various figures are not drawn to scale. For the sake of clarity, only the elements useful for understanding the embodiments described have been shown and are detailed.

[0066] In particular, an antenna with a transmitting array will be described below; the manufacturing methods of the transmitting and source arrays will not be detailed, the production of the structures described being within the reach of those skilled in the art from the indications of the present description, for example using standard printed circuit manufacturing techniques.

[0067] [Fig. 1] is a schematic sectional view of an example of an antenna 10 according to the invention. Such an antenna comprises one or more electromagnetic sources 20 carried by a first wall 25 radiating into a resonant cavity 30 and a transmitter network 40 carried by a second wall 55. The network 40 comprises a plurality of elementary cells 45, for example arranged in a matrix according to regular rows and columns. Each cell 45 comprises a receiver 50 extending from a surface of the second wall 55 extending into the resonant cavity 30, an emitter 60 extending on the opposite surface of the second wall 55 towards the outside and an interconnector 65 connecting the receiver 50 to the emitter 60. Each cell 45 is capable of capturing a wave in the cavity 30 with the receiver 50 and of re-emitting this radiation from its emitter 60 by applying, preferably, a phase shift A <1> and / or an amplitude weighting A via interconnector 65.With such an antenna, the source(s) 20 emit a wave into the resonant cavity 30 at or near a resonant frequency of the cavity 30 so that a resonant standing wave is formed in the resonant cavity 30. The receivers 50 pick up the standing wave at their respective positions and transmit the picked up signal to the corresponding transmitter 60 via the interconnector 65 with a phase modification A <1> and / or amplitude A. The transmitters 60 then emit a wave having a predetermined radiation pattern.

[0068] The resonant cavity 30 is delimited by the first wall 25, the second wall 55 and at least one side wall 75. These walls have surfaces internal to the cavity at least partially reflecting towards the cavity, that is to say having a surface reflecting at least 50%, better still at least 70%, even better still at least 90% of the wave. Preferably, the cavity 30 is of cylindrical shape, the first wall 25 and second wall 55 may be parallel to each other as illustrated and of identical contours to form the bases of the cylinder. They may have circular, oval or polygonal contours.

[0069] In the case of a circular contour, the cavity 30 may be delimited by a single lateral wall. In the case of a polygonal contour, the cavity 30 may be delimited laterally by at least two opposite lateral surfaces. In this case, the cavity may have lateral edges without walls, in particular to facilitate access to the cavity or may have lateral edges all delimited by a wall. The walls may be solid and at least partially reflective on all their surfaces or have areas of less reflection or transparency, in particular through openings, in particular slots.

[0070] The cavity may have a thickness c of between X and 100 / ., better between X and 10X, X being the wavelength of the resonance wave.

[0071] The resonant cavity may be empty of any material other than air. Alternatively, the resonant cavity may be filled with a dielectric substrate.

[0072] The source(s) 20 are shown carried by the first wall. But the invention is not limited to this positioning. The source(s) could be carried by the side wall 75 or the second wall 55, as illustrated in [Fig. 4]. The formation of the resonance wave in the cavity 30 allows greater positioning versatility for the source(s) 20 because it is not necessary for the emitted wave to be in the direction of the transmitter network 40.

[0073] The source(s) may emit the wave at a non-zero distance from the wall carrying them. The source(s) 20 may comprise a plunger 22 extending into the resonant cavity 30 transversely to the mean plane of the first wall 25. The plunger 22 may comprise a disc 23 forming an excess thickness at its end extending into the resonant cavity 25. The plunger 22 may extend into the cavity over a length greater than or equal to 10 mm and less than or equal to 30 mm, for example equal to 17 mm. The source(s) may be electrically connected to a transmitter, in particular via a coaxial cable.

[0074] The or each source is advantageously configured to emit a wave at a frequency between 1 GHz and 1 THz, preferably between 10 GHz and 300 GHz.

[0075] In the example illustrated in [Fig. 1], the antenna comprises a source 20 positioned on the first wall substantially centrally relative to the cavity 30. As illustrated in [Fig. 2], the invention is not limited to such central positioning and it could be positioned elsewhere on the first wall 25. The wave emitted by the source 20 may be emitted transversely to the wall carrying the source as illustrated. Alternatively, it may be emitted in a direction forming an angle with the wall other than 90°.

[0076] In the example illustrated in [Fig. 1], the antenna comprises a single source 20 positioned on the first wall centrally relative to the cavity. As illustrated in [Fig. 3], the invention is not limited to a single source 20. The antenna may comprise a plurality of sources 20 arranged on one of the walls, in particular the first wall 25, to emit a wave into the cavity 30. The sources 20 may be arranged in a regular matrix. The sources may or may not be coupled and emit a wave at identical or different distances from the first wall.

[0077] The standing wave forming in the cavity can be as shown in [Fig.5], representing the amplitude of the electric field in a section of the cavity for a resonant cavity in its TM440 mode at 2833 MHz. It can be seen that the standing wave has amplitude peak zones 200 called antinodes and amplitude trough zones 250 called wells.

[0078] The transmitter network 40 may comprise elementary cells 45 arranged according to a regular square matrix as illustrated in [Fig.7]. The structure of this transmitter network is possibly adapted for a resonant cavity in its mode TM440 at 2833 MHz according to the standing wave of [Fig.5].

[0079] [Fig.6] illustrates an example of a possible elementary cell adapted for a resonant cavity on its TM440 mode at 2833 MHz according to the standing wave of [Fig.5]. The invention is not limited to this type of elementary cell. All types of elementary cells known for use on a transmitter network can be used as a variant of the example described below.

[0080] The elementary cell 45 may comprise a conductive zone 100 extending over the second wall on a dielectric layer, in particular on the outer side of the latter, and a ground plane (not shown) spaced from the conductive zone by the dielectric layer. The conductive zone may comprise a slot 130, in particular U-shaped. The orientation of the slot 130 may at least partially define the phase shift. The ground plane may be a single continuous conductive layer for all the elementary cells of the transmitter network connected to ground and comprising holes at the level of each cell. The elementary cells may each comprise a plunger 110 extending from the conductive zone 100 through the dielectric layer and into a hole in the ground plane. The plungers 110 extend into the resonant cavity preferably transversely to the second wall 55.The plungers 110 may comprise a disc 120 forming an excess thickness at their ends extending into the resonant cavity 30. Such plungers 110 are configured to receive the energy and transmit it to the conductive layer 100 forming the emitter. The discs form the receivers and the plungers form the interconnectors. The plungers 110 extend into the cavity over a length greater than or equal to 10 mm and less than or equal to 30 mm. The plungers may have a diameter less than or equal to 3 mm, for example substantially equal to 1.2 mm. The disc 120 may have a thickness less than or equal to 3 mm, for example substantially equal to 1 mm and a diameter greater than the diameter of the plunger and less than or equal to 10 mm, for example substantially equal to 4 mm. Preferably, the plunger extends from the center of the conductive zone forming the emitter.

[0081] The elementary cells are all substantially the same shape apart from their orientation.

[0082] In the case of the elementary cell described above, the orientation of the slit defines the phase shift of the wave and the length of the plunger defines the amplitude weighting of the wave.

[0083] The length L of the conductive layer may be between 20 mm and 100 mm, for example substantially equal to 47 mm. The width l of the conductive layer may be between 10 mm and 80 mm, for example substantially equal to 30 mm. The slot 130 may comprise a main axis of extension extending over the width, the slot being centered on the length of the conductive layer. The U-shaped slot 130 may have a length F greater than or equal to 50% of the width of the conductive layer, for example substantially equal to 18 mm, and a total width of the U of between 2 and 10 mm, for example substantially equal to 5 mm. The width d of the slot is between 0.5 mm and 3 mm, for example substantially equal to 1.5 mm. The U may be offset in the width of the conductive layer so that the ends of the U are closer to the edge of the conductive layer than the base of the U. The ends of the U may be substantially 2 mm from the nearest edge of the conductive layer.

[0084] The elementary cells 45 are preferably decoupled from each other, the emitters and the receivers not being electrically connected to each other. Their conductive layers 100 may be spaced apart from each other by spaces in the width dx and in the length dy of dimension greater than or equal to 5 mm, better still greater than or equal to 10 mm, for example substantially equal to 10 mm in the length of the elementary cells 100 and substantially equal to 28 mm in the width of the elementary cells 100.

[0085] The plungers of the elementary cells in the cavity are arranged so as to be spaced from the plunger(s) of the end(s) of the plunger(s) of the sources by a distance p, illustrated in [Fig.l], greater than or equal to X / 2, better still greater than or equal to X.

[0086] In the example illustrated, the transmitter network 40 comprises 16 elementary cells. In practice, the transmitter network 40 may comprise a much higher number of elementary cells 45, for example of the order of 1000 elementary cells or more. The transmitter network may be symmetrical with respect to at least two transverse planes X and Y.

[0087] Preferably, the elementary cells 45 of the transmitter network take N different configurations, corresponding to the N different phase shift / amplitude weighting pairs, N being greater than or equal to 2. Each configuration can be taken by one or more elementary cells depending on the wave to be transmitted.

[0088] In the embodiment illustrated in [Fig.7], the transmitter network 40 has three different configurations denoted 45b, 452, and 453 having the phase shift / amplitude weighting pairs represented by the following slot orientation / plunger length pairs [0°, 12 mm] for the 45b cells, [0°, 24 mm] for the 452 cells, and [180°, 18 mm] for the 453 cells. This distribution of the elementary cells of each configuration was chosen as a function of the standing wave in the cavity and the desired transmitted wave, the identical cells corresponding to substantially identical points of the standing wave and preferably to antinodes 200 of the standing wave. The plungers 110i, 1102, and 1103 are visible in [Fig.5] at their respective positions relative to the amplitude of the section of the standing wave illustrated. Having a different length of the plungers in the cavity allows to capture Fonde at a different depth in the cavity, which allows to have an amplitude weighting by the variation of amplitude of the standing wave in the thickness of the cavity.

[0089] The characteristics of the wave transmitted by the antenna, and in particular its shape and its pointing direction, depend on the values ​​of the phase shifts A <1> and amplitude weighting A introduced by the different cells 45.

[0090] The conductive layer and the ground plane of the transmitter network 40 of the figures can be produced in planar technology, for example on a printed circuit board, or on a substrate made of silicon, quartz, etc. as is known.

[0091] In the illustrated embodiment, the phase shift and the amplitude weighting are imposed by the structure of the elementary cells, in particular the length of the plunger and the orientation of the slot. The invention is however not limited to passive interconnectors. The elementary cells can be configured so that the phase shift and / or the amplitude weighting are configurable, in particular via a control member for these parameters for each cell or for groups of cells.

[0092] The example antenna described is particularly useful for application in nano-satellites. Nevertheless, use in other fields such as those mentioned above is perfectly conceivable, possibly with some adaptations.

[0093] The invention is not limited to the embodiments described. Those skilled in the art are able to consider their technically operational combinations, and to substitute equivalents for them or to replace the elementary cells described with other elementary cells known in particular in the context of a transmitter network, in particular those described in the following articles:

[0094] - H. Kaouach, “Design and characterization of circularly-polarized discrete lens antennas in 60-GHz,” IEEE Antennas and Wireless Propagation Letters, vol. 15, pp. 1200-1203, 2016.

[0095] - H. Kaouach, A. Kabashi, “High-Efficiency Wideband Transmit-array Antenna with Linear Polarization in Q-Band”, Elsevier, AEUE - International Journal of Electronics and Communications, Vol. 70, No. 9, pp. 1275-1281, Sept. 2016- H. Kaouach, A. Kabashi, “Simple Tri-Layer Linearly-polarized Discrète Lens Antenna with High-Efficiency for mmWave Applications”IEEE Antennas and Wireless Propagation Letters, Vol. 15, pp. 259-262, 2015

[0096] - H. Kaouach, “Wideband high-efficiency unit-cell for 1 -bit and 2-bit transmit-arrays operating in X-Band” 1 Ith European Conférence on Antennas and Propagation (EUCAP 2017), Pages: 2320 - 2324, Paris, France, 2017.- H. Kaouach, et al, "Wideband Low-Loss Linear and Circulai Polarization Transmit-Arrays in V-Band," in IEEE Transactions on Antennas and Propagation, vol. 59, no. 7, pp. 2513-2523, July 2011, doi: 10.1109 / TAP.2011.2152331,

[0097] - Antonio Clemente, et al. “Wideband 400-element electronically reconfigurable transmitterray in X band.” IEEE Transactions on Antennas and Propagation, 2013, 61(10), pp. 5017–5027

[0098] - H. Kaouach and O. Pigaglio, "Operating Wideband 196-Element Transmit-Arrays." in mmWave Bands; Design & Demonstration," 2021 IEEE Conference on Antenna Measurements & Applications (CAMA), Antibes Juan-les-Pins, France, 2021, pp. 177-180, doi: 10.1109 / CAMA49227.2021.9703574.

[0099] - Antonio Clemente, et al.. « Reconfigurable unit-cells for beam-scanning trans- mitarrays in X band.” European Conf. on Antennas and Propagation, EuCAP 2013, Apr 2013, Gothenburg, Sweden.

[0100] - Alessandro de Oliveira Goat Junior, Jeanne Pages-Mounic, Andre Barka, Hamza Kaouach. Linearly Polarized Transmit-array Operating in cmWave Bands, Design, Op-timization and Démonstration. 16th European Conférence on Antennas and Propagation (EuCAP) 2022, Mar 2022, Madrid, Spain. pp.1-5.

Claims

Claims

1. Antenna (10) comprising: - a first wall (25) and - a second wall (55) extending at least partially opposite the first wall (25), the surfaces of the first and second walls opposite each other being at least partially reflective of electromagnetic waves and defining between them a cavity (30), - at least one lateral wall (75) of the cavity (30) connecting the first and second walls (25, 55) together and having a surface internal to the cavity (30) at least partially reflective of electromagnetic waves, the cavity being a resonant cavity of the electromagnetic wave, the antenna further comprising - at least one electromagnetic source (20) carried by one of the first wall (25), the second wall (55) and the lateral wall (75) and being configured to emit an electromagnetic wave into the resonant cavity (30),- at least one transmitter network (40) carried at least by the second wall (55), the transmitter network (40) comprising at least two elementary cells (45), each elementary cell comprising: • an electromagnetic receiver (120) extending into the resonant cavity (30), • an electromagnetic transmitter (60) extending outside the resonant cavity (30), • an interconnector (110) configured to transmit an electromagnetic wave picked up by the electromagnetic receiver (120) to the electromagnetic transmitter (60), at least one of the elementary cells (45) being configured so that the phase of the wave emitted by the transmitter (60) is modified relative to that of the wave received by the receiver (120).,

2. An antenna according to claim 1, wherein the resonant cavity (30) is cylindrical in shape, the first wall and the second wall (25, 55) forming the bases of the cylindrical shape and the side wall (75) at least partially forming the side surface of the cylindrical shape.

3. Antenna according to any one of the preceding claims, in which the first wall (25), second wall (55) and / or the side wall(s) (75) comprise one or more through openings and / or zones transparent to the wave or for reflection of the reduced wave.

4. An antenna according to any preceding claim, wherein the antenna is configured such that more than 50%, more preferably more than 70%, of the wave remains in the resonant cavity (30) to form the resonant standing wave.

5. Antenna according to any one of the preceding claims, in which the distance c between the first wall (25) and the second wall (55) is between X and 100X, better between X and 10X, X being the wavelength of the waves emitted by the source (20).

6. Antenna according to any one of the preceding claims, comprising a plurality of electromagnetic sources (20) carried by the same wall (25, 55, 75).

7. Antenna according to any one of the preceding claims, in which the source(s) (20) are configured to emit a wave into the resonant cavity (30) at a non-zero distance from the wall (25, 55, 75) carrying them, in particular the source(s) (20) each comprising a plunger (22) extending into the resonant cavity (30) transversely to the mean plane of the wall (25, 55, 75) carrying it, in particular extending and a disc (23) forming an excess thickness at the end of the plunger (22) extending into the resonant cavity (30).

8. Antenna according to any one of the preceding claims, in which the transmitter network (40) comprises more than two elementary cells (45) arranged on the second wall in a matrix according to rows and / or columns, in particular in a square matrix with the elementary cells (45) equally distributed in the matrix.

9. Antenna according to any one of the preceding claims, in which the transmitting network (40) is symmetrical with respect to at least one transverse plane, more preferably at least two transverse planes.

10. An antenna according to any preceding claim, wherein the transmitting array (40) comprises at least one layer forming a matrix of conductive zones (100) extending over the second wall (55), on the outer side of the latter, and a ground plane spaced from the conductive layer (100) by a dielectric layer, the conductive zones (100) forming the emitters (60) of the elementary cells (45), the elementary cells (45) each comprising a plunger (110) extending from the corresponding conductive zone (100) through the dielectric layer and into openings in the ground plane, the plungers (110) extending into the resonant cavity (30) transversely to the second wall (55) and comprising a disc (120) forming an excess thickness at their ends extending into the resonant cavity (30), the conductive zones (100) each comprising a slot (130), in particular U-shaped.

11. Antenna according to any one of the preceding claims, in which the transmitter network (40) comprises N configurations of distinct elementary cells (45), N being greater than or equal to 2, the N configurations having different pairs of phase shifts and amplitude weightings.

12. Antenna according to claim 11, in which at least two of the N configurations have different amplitude weightings, in particular the plungers (110) of the elementary cells (45) of said two configurations extending in the resonant cavity (30) over different lengths.

13. Antenna according to claim 11 or 12, in which at least two of the N configurations have different phase shifts, in particular the slots (130) of the elementary cells (45) of the two configurations being oriented differently.

14. Antenna according to any one of the preceding claims, in which the elementary cells (45) of the transmitter network (40) are positioned at a non-zero distance from the or all of the electromagnetic sources (20), in particular the discs (120) of the elementary cells (45) in the resonant cavity (30) being spaced from the or all of the electromagnetic sources (20), by a distance p greater than or equal to X / 2, better still greater than or equal to X, X being the wavelength of the waves emitted by the source.

15. An antenna according to any preceding claim, wherein the receivers (120) of the transmitter array are each configured to pick up the electromagnetic wave in resonance in the resonant cavity (30) in an area not corresponding to a well of the standing wave in resonance in the resonant cavity (30), preferably capturing the wave in an area corresponding substantially to a stationary Fonde antinode in resonance in the cavity.

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