EP4207493B1 - Passive directional rf antenna with one or two-dimensional scanning - Google Patents

Description

Technical area :

The invention lies in the field of antennas, and more particularly directional antennas. It applies in particular to antennas operating in the HF (Hyper Frequencies) frequency band, spanning the 300 MHz to 300 GHz band, but can apply to any frequency band for which the waves electromagnetics can be transmitted by waveguides.

Prior technique :

In order to maximize the link budget of radio frequency communications, or to make a link more selective in space, it is customary to use directional antennas, which make it possible to precisely orient the antenna or its maximum radiation in the desired direction, often without moving the antenna.

For this, the most common solution consists of using passive electronic scanning antennas (in English the term Passive Electronic Scanner Array, PESA) or active (in English Active Electronic Scanner Array, AESA), which make it possible to direct the beam of antenna radiation without mechanical intervention. However, these solutions are complex to implement, both in hardware and software. Indeed, the principle is to use one phase shifter element per unit antenna of the network, resulting in quickly thousands of phase shifters to be controlled simultaneously. These antennas are therefore complex to implement and expensive. JP H06 82969 B2 discloses a directional antenna array including a waveguide. The waveguide cavity includes a dielectric element that moves in translation to change the direction of radiation of the guide.

Another family of scanning antennas brings together “quasi-optical” devices, based on transmission (lens) or reflection (mirror), in which the position of the source is varied to direct the antenna beam. . However, these devices are most often bulky (lenses, mirrors or the like) and not very effective.

Other types of devices are known, such as for example the VICTS device (in English Variable Inclination Continuons Transverse Stub ) described in the patent US 9,413,073 B2 . It uses the rotation of two superimposed plates, each acting as a “prism” deflecting the beam in azimuth and elevation. However, although the lens thickness of this device is reduced compared to quasi-optical devices, it remains bulky. Additionally, rotation-based VICTS devices can only address circular antennas.

Generally speaking, rotation-based devices only address circular antennas, while non-rotation-based devices generally require significant movement of the radio frequency (RF) source with respect to the focusing system (mirror). , lens), hence problems of junctions, losses, etc.

Also known from the prior art are slot array antennas, comprising a waveguide on which a plurality of radiating elements, generally slots, are arranged. The wave propagating in the guide is emitted by each of the slots, with a phase shift which depends on the spacing between the radiating elements and the guided wavelength. The direction of the beam of such an antenna can therefore be directed by modifying the wavelength of the signal propagating in the guide. However, such a modification generally involves a modification of the frequency, which is generally incompatible with the rest of the radio chain whose frequency is dictated by other requirements.

An object of the invention is therefore to propose a simple antenna system making it possible to control a network of N phased antennas without having to resort to N "electronic" phase shifters (that is to say electrically powered and independently controlled), and without use optical or quasi-optical systems.

Summary of the invention :

To this end, the present invention describes a directional antenna array according to claim 1.

In the directional antenna array according to the invention, the bottom part of the rectangular waveguide is movable in translation in a direction of movement Oz parallel to the side faces, the maximum distance between the bottom part and the upper face being less than the distance between the side faces.

In one embodiment of the invention, the bottom part comprises a core extending along the longitudinal axis Oy. It further comprises at least a first row of bars extending respectively from the core in a direction Ox perpendicular to the longitudinal axis Oy and to the direction of movement of the bottom piece Oz.

• N réseaux d'antennes directifs selon l'invention, avec N supérieur ou égal à 1,
• des moyens d'ajustement de la position de la pièce de fond des N réseaux d'antennes directifs, configurés pour ajuster la position de la pièce de fond des N guides d'ondes en fonction d'une direction de faisceau antennaire recherchée.

The invention also relates to a directional radio frequency antenna comprising:

• N directional antenna networks according to the invention, with N greater than or equal to 1,
• means for adjusting the position of the bottom piece of the N directional antenna arrays, configured to adjust the position of the bottom piece of the N waveguides as a function of a desired antenna beam direction.

In one embodiment, the directional radio frequency antenna according to the invention comprises N identical directional antenna arrays arranged in parallel directions and aligned. Adjusting the position of the bottom piece of the waveguides of the N antenna arrays makes it possible to orient the antenna beam in a plane Oyz comprising said longitudinal axis Oy and an axis Oz perpendicular to the axis longitudinal and parallel to the lateral faces of the waveguide(s) of the directional antenna array.

In another embodiment of the directional radio frequency antenna according to the invention, where N is greater than or equal to three, it comprises N-1 identical directional antenna arrays arranged in parallel and aligned directions, and a separate directional antenna array configured so that its radiating elements radiate into ports of said N-1 directional antenna arrays. This last antenna network is therefore used as a divider with one input and N-1 outputs (reciprocally a combiner with one output and N-1 inputs) whose phase shift is adjustable.

• l'écart entre la face supérieure et la pièce de fond des guides d'ondes des N -1 réseaux d'antennes directifs est le même pour chacun de ces guides d'ondes, et l'ajustement de la position des pièces de fond des guides d'ondes des N -1 réseaux d'antennes directifs permet d'orienter le faisceau de l'antenne dans un plan Oyz comprenant un axe Oy parallèle à l'axe longitudinal des N-1 réseaux d'antennes directifs, et un axe Oz perpendiculaire à ces axes longitudinaux et parallèle aux faces latérales des guides d'ondes des N-1 réseaux d'antennes directifs ;
• la position de la pièce de fond du guide d'ondes du réseau d'antennes directif distinct permet d'orienter le faisceau de l'antenne dans un plan Oxz orthogonal à l'axe longitudinal Oy des N-1 réseaux d'antennes directifs.

Advantageously:

• the distance between the upper face and the bottom piece of the wave guides of the N -1 directional antenna arrays is the same for each of these wave guides, and the adjustment of the position of the bottom pieces of the waveguides of the N -1 directional antenna arrays make it possible to orient the antenna beam in a plane Oyz comprising an axis Oy parallel to the longitudinal axis of the N-1 directional antenna arrays, and an axis Oz perpendicular to these longitudinal axes and parallel to the lateral faces of the waveguides of the N-1 directional antenna arrays;
• the position of the bottom piece of the waveguide of the distinct directional antenna array makes it possible to orient the antenna beam in a plane Oxz orthogonal to the longitudinal axis Oy of the N-1 directional antenna arrays.

The invention also relates to a method of configuring the pointing direction of a directional radio frequency antenna according to claim 7.

Finally, the invention relates to a computer program comprising program code instructions for executing the steps of the method according to the invention when said program is executed on a computer.

Brief description of the figures :

• [Fig. 1a] La figure 1a représente un premier mode de réalisation d'un réseau d'antennes directif passif selon l'invention ;
• [Fig. 1b] La figure 1b est une représentation de l'intérieur du réseau d'antennes de la figure 1a ;
• [Fig. 2a] La figure 2a illustre schématiquement le fonctionnement du réseau d'antennes, pour une longueur d'ondes donnée ;
• [Fig. 2b] La figure 2b illustre schématiquement le fonctionnement du même réseau d'antennes qu'a la figure 2a, pour une autre longueur d'ondes ;
• [Fig. 3a] La figure 3a représente le diagramme de rayonnement obtenu par un réseau d'antennes directif selon un mode de réalisation de l'invention, pour un déphasage donné ;
• [Fig. 3b] La figure 3b représente le diagramme de rayonnement obtenu par le même réseau d'antennes directif qu'à la figure 3a, pour un autre déphasage ;
• [Fig. 4] La figure 4 représente un guide d'ondes électromagnétique permettant de mettre en oeuvre l'invention ;
• [Fig. 5a] La figure 5a représente un mode de réalisation d'une antenne RF directive 2D selon l'invention ;
• [Fig. 5b] La figure 5b représente est une représentation de l'intérieur de l'antenne RF directive 2D de la figure 5a ;
• [Fig. 6a] La figure 6a représente le diagramme de rayonnement obtenu par une antenne RF directive 2D selon un mode de réalisation de l'invention, pour un déphasage donné ;
• [Fig. 6b] La figure 6b représente le diagramme de rayonnement obtenu par la même antenne RF directive 2D qu'à la figure 6a, pour un autre déphasage ;
• [Fig. 7] La figure 7 décrit schématiquement les étapes d'un procédé de configuration de la direction de pointage d'une antenne radiofréquence directive mise en oeuvre à partir des réseaux d'antennes selon l'invention.

The invention will be better understood and other characteristics, details and advantages will appear better on reading the description which follows, given on a non-limiting basis, and thanks to the appended figures, given by way of example.

• [ Fig. 1a ] There figure 1a represents a first embodiment of a passive directional antenna array according to the invention;
• [ Fig. 1b ] There figure 1b is a representation of the interior of the antenna array of the figure 1a ;
• [ Fig. 2a ] There figure 2a schematically illustrates the operation of the antenna array, for a given wavelength;
• [ Fig. 2b ] There figure 2b schematically illustrates the operation of the same antenna network as in the figure 2a , for another wavelength;
• [ Fig. 3a ] There figure 3a represents the radiation pattern obtained by a directional antenna array according to one embodiment of the invention, for a given phase shift;
• [ Fig. 3b ] There figure 3b represents the radiation pattern obtained by the same directional antenna array as in the figure 3a , for another phase shift;
• [ Fig. 4 ] There figure 4 represents an electromagnetic waveguide making it possible to implement the invention;
• [ Fig. 5a ] There figure 5a represents an embodiment of a 2D directive RF antenna according to the invention;
• [ Fig. 5b ] There figure 5b represents is a representation of the interior of the 2D directive RF antenna of the figure 5a ;
• [ Fig. 6a ] There figure 6a represents the radiation pattern obtained by a 2D directive RF antenna according to one embodiment of the invention, for a given phase shift;
• [ Fig. 6b ] There figure 6b represents the radiation pattern obtained by the same 2D directive RF antenna as in the figure 6a , for another phase shift;
• [ Fig. 7 ] There Figure 7 schematically describes the steps of a method of configuring the pointing direction of a directional radio frequency antenna implemented from antenna networks according to the invention.

Identical references are used in different figures when they designate identical or comparable elements.

Detailed description :

In order to respond to the defects of the prior art, the invention describes a slot guide type antenna making it possible to direct the pointing direction of the beam by mechanical action on the position of a bottom wall of the guide.

There figure 1a represents a first embodiment of a passive directional antenna array 100 according to the invention.

It comprises a rectangular waveguide 101, adapted to the propagation of an electromagnetic wave having a given maximum frequency. For example, the waveguide may have a waveguide width of order of magnitude approximately half the guided wavelength it carries. The waveguide 101 extends along a longitudinal axis Oy (O being the center of the waveguide). On the waveguide are arranged a plurality of radiating elements 102, regularly along the axis Oy. The waveguide comprises an input and an output, which can either be accesses 103 or 104. When the The antenna is used in transmission, the signal to be transmitted is injected onto an access point of the guide, radiated by the radiating elements as it propagates in the waveguide, and ends up in the output, which is generally connected to a residual signal absorption element, such as a charge. When the antenna is used in reception, the ambient radio frequency signal is captured successively by the radiating elements, and propagates in the waveguide until the exit of the guide, connected to elements allowing it to be processed (radiofrequency chain, analog/digital converter, digital processing means, etc.).

Subsequently, the directional antenna array according to the invention is described in connection with a transmitting antenna, but applies in the same manner regardless of whether the antenna array is used for transmission or reception.

The simplest way of implementing the radiating elements 102 of the directional antenna network consists of making slots in the waveguide. However, other embodiments are possible, for example by using as radiating elements patch type antennas, a printed dipole, a printed spiral, or others, powered by a means making it possible to couple the energy of the guide towards the radiating element, such as for example a coaxial cable plunging into the waveguide. Subsequently, the invention will be described using slots as radiating elements, but can be implemented in different ways.

.An electromagnetic wave propagating between access 103 and access 104 of the wave guide successively excites the different radiating elements 102. Each radiating element captures part of the energy of the wave proportional to its surface, and the emits outside the waveguide. Two adjacent radiating elements spaced a distance Δ y therefore emit the electromagnetic wave with a phase shift Δ ϕ , which depends on Δ y and the wavelength λ of the electromagnetic wave. This phase shift makes it possible to shift the beam of the antenna array along the axis Oy by an angle α relative to the normal of the array such that $\mathit{\Delta \varphi }=2\pi .\mathit{\Delta y}.\sin \left(\raisebox{1ex}{$\alpha $}\!\left/ \!\raisebox{-1ex}{$\lambda $}\right.\right)$

.

The phase shift between two radiating elements of the passive antenna array therefore depends on the wavelength of the transmitted signal, the shape of the slots and their spacing. The direction of the antenna beam depends directly on this phase shift.

This operation corresponds to the state of the art of slotted guide type antennas.

The invention stands out from the state of the art in that the waveguide comprises a fixed part, comprising the upper face and the two sides of the waveguide (the sides corresponding to the shortest lengths of the slice of the rectangular waveguide) and a bottom part movable in translation between the two sides, so that the height of the cavity located inside the waveguide can be adjusted without modifying the width of the guide, and therefore without modifying its cutoff frequency. The movable bottom part constitutes the lower face, or bottom wall, of the waveguide.

In the representation of the figures, the radiating elements are positioned on the upper face of the waveguide. Alternatively, they can be positioned on one side of the waveguide, or on both sides.

There figure 1b is a representation of the interior of the antenna array of the figure 1a . We see the bottom part 110 of the waveguide, movable in translation along the axis Oz. The variation in the height of the waveguide, obtained by modifying the position of the movable bottom part, modifies the length of the electromagnetic wave passing through the waveguide, and therefore the direction of radiation of the beam emitted by the antenna network.

THE figures 2a and 2b schematically illustrate the operation of the antenna network according to the invention.

On the figure 2a show the upper face 201 and the movable bottom part 202 of the waveguide, which constitutes its lower face. On the upper face are made slots 203, which have the function of radiating elements for an electromagnetic wave 204 transmitted in the waveguide. The upper face and the bottom piece are separated by a distance h ₁ . The electromagnetic wave propagates in the waveguide with a wavelength λ ₁ .

There figure 2b uses the same elements, but with a distance h ₂ greater than h ₁ between the upper face and the bottom piece. As a result, the electromagnetic wave propagates with a wavelength λ ₂ less than λ ₁ . In the example of figures 2a and 2b , we have λ ₁ = 2.λ ₂ , for the same distance Δy between the radiating elements. Changing the position of the bottom piece 202 causes a change in the wavelength of the guided signal, which modifies the phase shift of the signals radiated by the radiating elements 203, and therefore the pointing direction of the antenna.

THE figures 3a and 3b represent the radiation pattern obtained by a directional antenna array according to one embodiment of the invention. By changing the position of the bottom piece of the waveguide, the guided wavelength in the waveguide of the figure 3a is different from that of the figure 3b , which has the consequence that the lobe of the radiation diagram in the Oyz plane, plane comprising the longitudinal axis Oy in which the antenna array extends and the axis Oz perpendicular to this longitudinal axis and parallel to the lateral faces of the waveguide, does not have the same inclination in the two figures.

The implementation of the invention requires the production of a waveguide having a bottom wall movable in translation. Such a waveguide (not shown) can be produced by separating the bottom wall of a waveguide, and by controlling it in translation by any mechanical element. This solution, however, has the disadvantage of having to be machined very finely since the movement of the bottom wall can be subject to friction deforming the waveguide and therefore deforming the guided electromagnetic waves, and since the connections between the back wall and sides must be electrically hermetic, again so as not to distort and attenuate the electromagnetic wave which propagates in the guide.

The inventors filed the patent application FR 2109055 (publication: FR 3 126 553 ), in which they describe a waveguide having a non-solid movable bottom part, presenting periodic patterns making it possible to close the waveguide in an electrically hermetic manner without the edges touching.

There figure 4 represents an electromagnetic waveguide as described in the patent application FR 2109055 , particularly suitable for the implementation of the invention.

This waveguide with a rectangular section comprises a fixed part with two side faces 402 and 403 facing each other on the short sides of the rectangle, and an upper face 401 joining the two side faces orthogonally. The waveguide also comprises a bottom part 404 movable in translation between the two side faces in the direction of movement D, parallel to the side faces, and which constitutes the lower face of the guide. The upper face, the two side faces and the bottom piece then form a conduit 410 of height H and width L, configured to guide the propagation of an electromagnetic wave in the waveguide. In order not to affect the cutoff frequency of the waveguide, the assembly is defined so that the height H is always less than the width L.

• une âme 405 s'étendant selon une direction parallèle à l'axe longitudinal du guide d'ondes, située à mi-distance des faces latérales 402 et 403, avec un bord supérieur en regard de la face supérieure du guide d'ondes ;
• une première rangée de barres 406 et 407 disposées régulièrement et s'étendant depuis le bord supérieur de l'âme 405 vers les faces latérales du guide d'ondes dans une direction parallèle à la face supérieure 401. Ces barres délimitent, avec le bord supérieur de l'âme 405, la pièce de fond 404 ;
• une deuxième rangée de barres 408 et 409 disposées régulièrement et s'étendant depuis l'âme 405 vers les faces latérales du guide d'ondes dans une direction parallèle à la face supérieure 401, positionnées sous la première rangée de barres.

In one embodiment, the bottom piece comprises:

• a core 405 extending in a direction parallel to the longitudinal axis of the waveguide, located halfway between the side faces 402 and 403, with an upper edge facing the upper face of the waveguide;
• a first row of bars 406 and 407 arranged regularly and extending from the upper edge of the core 405 towards the side faces of the waveguide in a direction parallel to the upper face 401. These bars delimit, with the upper edge of the soul 405, the bottom piece 404;
• a second row of bars 408 and 409 arranged regularly and extending from the core 405 towards the side faces of the waveguide in a direction parallel to the upper face 401, positioned under the first row of bars.

According to other embodiments, the bottom piece may comprise only a single row of bars, or more than two rows of bars. The bars of successive rows can be of identical geometries and/or aligned.

According to one embodiment, the bottom part 404 or the upper face 401 of the waveguide may comprise a rib extending inside the cavity 410 over the entire length of the waveguide in a direction parallel to its longitudinal axis. Such a rib makes it possible to reduce the dimension of the waveguide relative to the guided wavelength.

A clearance is preferably formed between the bars and the side faces, which allows the bottom part 404 to move without friction with the side faces 402 and 403.

Bars 406 to 408 are dimensioned as explained in the article from Berenguer, Antonio & Fusco, VF & Baquero, M. & Boria, Vicente: “A frequency-dependent equivalence between groove gap waveguide and rectangular waveguide”, 2016 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting .

Due to its geometric properties, the bottom piece forms an electrically hermetic wall for the electromagnetic waves transmitted in the waveguide. Not necessarily being joined to the side walls, it can be easily moved in translation between these two walls.

The assembly formed by the fixed part and the mobile part is made of a conductive material, such as copper, brass, silver or titanium, or a plastic material covered with a thin metallic layer.

A means of adjusting the position of the bottom part, such as a motor, for example a stepper motor, a piezoelectric motor or a coil motor controlled by a regulating device, can be configured to adjust the position of the bottom piece, and therefore the height H of the conduit 410 of the waveguide.

The waveguide shown in figure 4 is therefore particularly suitable for the implementation of an array antenna according to the invention since it makes it possible to vary the volume of the internal cavity of the waveguide while being electrically hermetic and without friction with the lateral faces.

The antenna array shown in figure 1a can be used as a directional radio frequency antenna for which the radiation pattern can be controlled in one plane, i.e. a 1D RF antenna.

However, several antenna arrays according to the invention can be implemented jointly so as to form a directive RF antenna whose radiation pattern can be controlled in two directions, i.e. a 2D RF antenna.

THE figures 5a and 5b represent an embodiment of a 2D directive RF antenna according to the invention.

• un premier réseau d'antennes 501, et
• N-1 réseaux d'antennes 502, 503, ..., 50N.

It includes the implementation of N antenna networks, with N greater than or equal to three:

• a first antenna network 501, and
• N-1 antenna arrays 502, 503, ..., 50N.

The N-1 directional antenna arrays 502 to 50N are identical and arranged so as to form aligned parallel lines. By identical we mean that the dimension of the waveguide of these antenna arrays are equal, and that they all include the same number of radiating elements spaced identically.

The waveguides which form the N-1 directional antenna arrays are each arranged along a longitudinal axis parallel to the axis Oy shown in the figure, with O the center of the array formed by the N-1 antenna arrays directives 502 to 50N.

The assembly is configured so that the radiating elements of the directional antenna array radiate into one of the access points of the N-1 other directional antenna arrays. This can be done, for example, by arranging the antenna array 501 in a direction perpendicular to the direction of the N-1 antenna arrays 502 at 50N, and by connecting the slots of the array 501 with the accesses of the arrays 502 to 50N, as on the figure 5a . In another embodiment, the waveguide 501 can have any orientation, the radiating elements of the waveguide 501 being connected to the accesses of the networks 502 to 50N by coaxial links of the same lengths. Other embodiments are possible.

The number of radiating elements of the antenna array 501 is equal to N-1. The length of the waveguide of the antenna array 501 and the spacing Δy' between its radiating elements of the array 501 are not necessarily equal to those of the waveguides of the arrays 502 at 50N.

There figure 5b represents the moving background parts of the access networks of the figure 5a . The bottom pieces 512 to 51N of the access networks 502 to 50N are configured so that the distance between the upper face of the waveguide and the bottom piece is the same for each of these waveguides. One possible embodiment consists of synchronizing the adjustment means ensuring the translation of these bottom parts. Another embodiment consists of making these bottom pieces integral, the bottom pieces being moved in translation by the same adjustment device.

The bottom piece 511 of the isolated antenna array 501 is moved in translation by an adjustment means independent of that of the other antenna arrays.

Thus, an electromagnetic wave injected into an access of the waveguide of the network 501 propagates through the waveguide, and radiates into the different accesses of the waveguides of the antenna networks 502 at 50N with a phase shift Δϕ '. It then propagates in each of the waveguides of the antenna arrays 502 at 50N by successively exciting the radiating elements with a phase shift Δϕ, identical for all the waveguides 502 at 50N.

Adjusting the height of the bottom piece of the wave guides 502 to 50N therefore makes it possible to vary the wavelength of the guided wave inside these wave guides, and therefore to orient the beam of the RF antenna in a plane Oyz comprising the axis Oy passing through the center of the network formed by the networks 502 to 50N and parallel to the axis in which each of the networks 502 to 50N extend, and the axis Oz perpendicular to Oy and parallel to the lateral faces of the waveguides of the networks 502 to 50N.

Adjusting the height of the bottom piece of the waveguide 501 makes it possible to vary the wavelength of the guided wave inside this waveguide, and therefore to orient the beam of the RF antenna in an Oxz plane orthogonal to the Oy axis.

THE figures 6a and 6b represent the radiation pattern obtained by a 2D directional antenna array according to one embodiment of the invention. In these figures given as an example, the antenna network represented resembles that of the figures 3a and 3b , however the simulations making it possible to generate the radiation pattern were carried out from a 2D antenna array with N = 9 antenna arrays arranged as on the figures 5a and 5b .

The guided wavelength of the antenna array 501 of the figure 6a is different from those of the figure 6b , by translation of the movable bottom part of the waveguide 501. It is observed that the insertion of several waveguides 503 at 50N in parallel and of the network 501 has modified the beam of the antenna, so that the radiation pattern of the 1D antenna presenting a large main lobe (around 180°) in the Oxz plane has become very directional, and therefore has a greater gain. We also observe, by difference between the figures 6a and 6b , that the beam can be directed in the Oxz plane, by adjusting the height of the bottom wall of the antenna array 501. In addition, the pointing direction can also be modified in the Oyz plane by translation of the part of bottom of waveguides 502 to 50N.

In another embodiment, not shown, the directional radio frequency antenna comprises N arrays of directional antennas according to the invention, with N greater than or equal to 2, arranged in parallel directions and aligned, like the guides 502 to 50N of there figure 5a . The bottom pieces of these guides are adjusted in a similar manner, so that at any given moment the wavelength guided is the same in all waveguides. The guides are powered by the same signal in phase. Such a device constitutes a directive RF antenna of which it is possible to direct the beam in the Oyz plane, as for the network of the figure 1a , but differs from it in that the main lobe of the radiation pattern of this antenna is reduced (and therefore has more gain) in the Oxz plane.

The antenna networks according to the invention, made from waveguides having a bottom part movable in translation making it possible to modify the height of the cavity of the waveguide in which the electromagnetic waves are transported, therefore make it possible to implement directional and orientable RF antennas in one or two dimensions, without mechanical action other than the presence of a motor making it possible to modify the bottom wall, and without active elements (phase shifters). They therefore respond to the technical problem posed.

The invention relates to an antenna array comprising a waveguide with a movable bottom piece and radiating elements and a directional radio frequency antenna implementing one or more of the antenna arrays according to the invention. It also relates to a method for configuring the pointing direction of a directive radio frequency antenna implemented from antenna networks according to the invention.

• une première étape 701 de calcul de la position des pièces de fond des guides d'ondes du ou des réseaux d'antennes de l'antenne radiofréquence directive. Cette étape consiste à calculer une position de pièce de fond dans le cas d'une antenne 1D, et deux positions (une position pour les guides alignés 502 à 50N et une position pour le guide isolé 501) dans le cas d'une antenne 2D. Les positions sont obtenues en considérant la direction de pointage recherchée, et le nombre, la position et l'espacement des éléments rayonnants sur les guides d'ondes ;
• une deuxième étape 702 de modification de la position des pièces de fond des guides d'ondes du ou des réseaux d'antennes directif. Cette étape se fait en actionnant les moyens d'ajustement (moteurs) reliés aux pièces de fond des guides d'ondes du ou des réseaux d'antennes, de manière à ce qu'ils soient positionnés comme calculé lors de la première étape.

The process is described schematically in Figure 7 . It is implemented on a directional radio frequency antenna comprising one or more antenna arrays according to the invention, and comprises:

• a first step 701 of calculating the position of the bottom pieces of the waveguides of the antenna array(s) of the directional radio frequency antenna. This step consists of calculating a bottom part position in the case of a 1D antenna, and two positions (one position for the aligned guides 502 to 50N and one position for the insulated guide 501) in the case of a 2D antenna . The positions are obtained by considering the desired pointing direction, and the number, position and spacing of the radiating elements on the waveguides;
• a second step 702 of modifying the position of the bottom parts of the waveguides of the directional antenna array(s). This step is done in actuating the adjustment means (motors) connected to the bottom pieces of the waveguides of the antenna array(s), so that they are positioned as calculated during the first step.

Finally, the invention also relates to a computer program comprising program code instructions for executing the steps of the method described above when said program is executed on a computer, or on any other calculation means such as a microprocessor, a DSP ( Digital Signal Processor) , an FPGA ( Field Programmable Gate Array ), an ASIC ( Application-Specific Integrated Circuit), or integrated circuit specific to an application), any combination of these means, or any hardware component making it possible to execute the steps of the method of configuring the pointing direction of a directive radio frequency antenna implemented from antenna networks according to the invention, and to send to the adjustment means instructions relating to the adjustment of the position of the bottom parts of the waveguides.

Claims (8)

1. A directional antenna array, comprising:

   - a rectangular waveguide (101) with two feeds (103, 104), the guide extending along a longitudinal axis (Oy), said rectangular waveguide comprising:

   • a fixed portion with two lateral faces (402, 403) facing each other and an upper face (401) joining the two lateral faces orthogonally, and

   • a bottom part (404) placed between the two lateral faces and forming the lower face of the waveguide;

   - a plurality of radiating elements (102) placed regularly along said longitudinal axis on the fixed portion of the waveguide,

   the directional antenna array being characterised in that the bottom part of the rectangular waveguide is movable translationally in a direction of movement (Oz) parallel to the lateral faces, the maximum distance (H) between the bottom part and the upper face being smaller than the distance (L) between the lateral faces.
2. The directional antenna array according to claim 1, wherein the bottom part comprises a core (405) extending along the longitudinal axis (Oy), the bottom part further comprising at least a first row of bars (406, 407) respectively extending from the core in a direction (Ox) perpendicular to the longitudinal axis (Oy) and to the direction of movement of the bottom part (Oz).
3. A directional radio-frequency antenna, comprising:

   - N directional antenna arrays according to one of claims 1 and 2, with N higher than or equal to 1,

   - means for adjusting the position of the bottom part of the N directional antenna arrays, configured to adjust the position of the bottom part of the N waveguides depending on a desired antenna-beam direction.
4. The directional radio-frequency antenna according to the preceding claim, comprising N identical directional antenna arrays placed in parallel directions and aligned, where adjustment of the position of the bottom part (404) of the waveguides of the N antenna arrays allows the beam of the antenna to be oriented in a plane (Oyz) comprising said longitudinal axis (Oy) and an axis (Oz) perpendicular to the longitudinal axis and parallel to the lateral faces (402, 403) of the waveguide(s) of the directional antenna array.
5. The directional radio-frequency antenna according to claim 3, with N higher than or equal to three, comprising N-1 identical directional antenna arrays placed in parallel directions and aligned, and a separate directional antenna array configured so that its radiating elements radiate into feeds of said N-1 directional antenna arrays.
6. The directional radio-frequency antenna according to the preceding claim, where:

   - the separation (H) between the upper face (401) and the bottom part (404) of the waveguides of the N-1 directional antenna arrays (502 to 50N) is the same for each of these waveguides, and where adjustment of the position of the bottom parts of the waveguides of the N-1 directional antenna arrays allows the beam of the antenna to be oriented in a plane (Oyz) comprising an axis (Oy) parallel to the longitudinal axis of the N-1 directional antenna arrays, and an axis (Oz) perpendicular to these longitudinal axes and parallel to the lateral faces (402, 403) of the waveguides of the N-1 directional antenna arrays;

   - the position of the bottom part of the waveguide of the separate directional antenna array (501) allows the beam of the antenna to be oriented in a plane (Oxz) orthogonal to the longitudinal axis (Oy) of the N-1 directional antenna arrays.
7. A method for configuring the pointing direction of a directional radio-frequency antenna, said radio-frequency antenna comprising:

   - N directional antenna arrays (100, 502 to 50N) according to one of claims 1 and 2, with N higher than or equal to 1,

   - means for adjusting the position of the bottom part of the N directional antenna arrays, configured to adjust the position of the bottom part of the N waveguides depending on a desired antenna-beam direction,

   the method being characterised in that it comprises:

   - a step (701) of computing the position of the bottom parts (404) of the waveguides of the directional antenna array(s) of the directional radio-frequency antenna, and

   - a step (702) of modifying the position of the bottom parts of the waveguides of the directional antenna array(s) as computed in the first step (701).
8. A computer program comprising program-code instructions for executing the steps of the method according to the preceding claim when said program is executed on a computer.

Images