Waveguide array with rounded cross-section

Abstract

Waveguide array (1) obtained by additive manufacturing, comprising an even number of waveguides arranged two-by-two so as to form at least one pair of waveguides, each pair of waveguides comprising: a first waveguide channel (10), and a second waveguide channel (11); wherein the first and second channels have a non-circular oval cross-section with an axis of symmetry (x) and at least one non-rectilinear portion, wherein the first waveguide and the second waveguide share a wall portion (100).

Description

Rounded section waveguide network Technical field

[0001] The present invention relates to a waveguide array and to an antenna array comprising such a waveguide array. State of the art

[0002] Radiofrequency waveguide networks are widely used in many areas of telecommunications, particularly in satellite telecommunications.

[0003] Satellite payload constraints limit the space and weight available for all onboard components, including antenna components and other passive radio frequency devices.

[0004] Additive manufacturing of such devices advantageously allows for complex geometries to be obtained, allowing optimization of the space occupied by the devices as well as a manufacturing method requiring very few assembly steps, thus reducing manufacturing time and cost. However, additive manufacturing also has certain constraints, particularly in terms of device geometry, in order to be feasible.

[0005] There is therefore a need for passive radiofrequency devices whose compactness is optimized, whose weight is reduced to a minimum and whose geometry is adapted for additive manufacturing.

[0006] There is also a need for alternative waveguide grating geometries, to provide the designer with greater design freedom.

[0007] Waveguide arrays often include matrix arrangements of rectangular cross-section waveguides, or honeycomb arrangements of hexagonal cross-section waveguides. In these arrangements, each waveguide except those at the edge of the array shares all of its walls with adjacent waveguides. This sharing of walls reduces the weight and size of the array.

[0008] Contrary to what one might intuitively imagine, these arrangements in which all the walls are shared do not always allow for an optimal ratio between the surface area of ​​the channels and the surface area of ​​the walls. Indeed, the walls of the waveguides must have sufficient thickness to guarantee the rigidity of the network as well as the evacuation of heat. This significant thickness of all the walls tends to weigh down the network and increase its size.

[0009] Furthermore, additive manufacturing of waveguide gratings with rectangular or hexagonal cross-section is difficult, due to the number of cantilevered walls during printing.

[0010] Arrays of circular waveguides arranged in a matrix have also been devised. In this arrangement, each waveguide shares only a very limited length of its contour with its neighbors, for example, four points. The ratio between the surface area of ​​the channels and the surface area of ​​the walls is therefore unfavorable. Brief summary of the invention

[0011] An object of the present invention is to provide a waveguide network free from the limitations present in the prior art.

[0012] Another aim of the invention is to propose a network of waveguides facilitating its additive manufacturing.

[0013] Another aim of the invention is to propose a waveguide network making it possible to limit the assembly steps during its manufacture.

[0014] Another aim of the invention is to propose a waveguide network with optimized compactness.

[0015] Another object of the invention is to provide a waveguide network that is lighter than the waveguide networks of the prior art.

[0016] According to the invention, these aims are achieved in particular by means of a network of waveguides obtained by additive manufacturing comprising waveguides arranged two by two so as to form at least one pair of waveguides, each pair of waveguides comprising: a first waveguide channel, and a second waveguide channel; the first and second channels comprise a non-circular oval cross-section with an axis of symmetry and at least one non-rectilinear portion, and in that the first waveguide and the second waveguide have a common wall portion.

[0017] An oval section is a section formed by a differentiable closed curve, which has at least one axis of symmetry and which resembles more or less an ellipse. Ellipse, egg, stadium, peanut shapes are for example considered in the present application as ovals.

[0018] Compared to networks formed from circular-section waveguides, the oval shape makes it possible to increase the portion of common walls shared between neighboring waveguides, and therefore to improve the ratio between the wall surface and the channel surface.

[0019] The oval shape also offers the advantage of being generally simpler to produce by additive manufacturing than other shapes which have more overhanging portions.

[0020] Oval shapes cannot be perfectly juxtaposed on a plane without leaving areas between these shapes. These areas, usually considered undesirable, are used in the invention by filling them, at least partially, so as to locally create thicker walls which reinforce the rigidity of the device and improve heat dissipation. Consequently, the other portions of shared walls, between these reinforcement areas, can be printed with a thinner thickness. Thus, and contrary to what one might think a priori, the imperfect juxtaposition of waveguide channels with the claimed shape makes it possible to create reinforcement areas which ultimately make it possible to reduce the thickness of the other walls, and therefore to reduce the weight and size of the network compared to networks formed from waveguides with a rectangular or hexagonal section in which all the walls are shared.

[0021] Alternatively, these reinforcement areas can be pierced with openings to dissipate heat and further reduce the weight of the network.

[0022] In a first embodiment, the first and second channels comprise a non-circular oval section with two axes of symmetry.

[0023] The waveguide channels alternately comprise, along their largest dimension, a first convex end, a concave connecting portion, and a second convex end.

[0024] The connecting portion may comprise two concave walls facing each other.

[0025] The dimension of the channel in a direction perpendicular to said largest dimension is greater at said ends than in the connecting portion.

[0026] In this embodiment, the section of the channel is thus substantially a section in the geometric shape of a peanut.

[0027] The contour of the ends forms for example a circular arc of at least 190°, preferably at least 210°. The connecting portion can connect to these ends are a direction tangential to these circular arcs.

[0028] A concave wall of the concave connecting portion may have a groove.

[0029] Two inner walls of the first waveguide and two inner walls of the second waveguide may each comprise a groove.

[0030] The array may comprise a first row (or slice) of waveguides juxtaposed in the direction of their greatest elongation, and a second row (or slice) of waveguides juxtaposed in the direction of their greatest elongation, the second row being offset half a waveguide length from the first line. Thus, a convex portion of each waveguide presses against the convex connecting portion of a waveguide on an adjacent line.

[0031] In another embodiment, the waveguide channels alternately comprise, along their largest dimension, a first convex end, and a second end formed of two non-parallel walls.

[0032] The waveguide channels then have a roughly water drop shape.

[0033] The non-parallel walls meet to form the second end of the canal.

[0034] The outline of the first convex end may form an arc of at least 180°.

[0035] Non-parallel walls can extend the first convex end along two tangents.

[0036] Each channel may have one or more grooves.

[0037] The network according to this second embodiment may comprise a first line of waveguides juxtaposed in a direction perpendicular to their greatest elongation, and a second line of waveguides juxtaposed in the direction of their greatest elongation, the two lines being head to tail, the second line being offset by half the width of the waveguide relative to the first line.

[0038] The array may comprise a third line of waveguides juxtaposed in a direction perpendicular to their greatest elongation, and a fourth line of waveguides juxtaposed in the direction of their greatest elongation, the third line being juxtaposed to the second line.

[0039] The waveguide network may further include Y-junctions to function as a combiner network.

[0040] An additively manufactured dual-polarized antenna array may include a waveguide array as above, and a plurality of radiating elements, each radiating element being coupled to the end of exactly one pair of waveguides in the array.

[0041] A section matching portion may be provided between each waveguide and each radiating element.

[0042] A septum may be provided between each radiating element and a pair of waveguides.

[0043] Such an antenna array may comprise at least eight waveguides and the pairs of waveguides being arranged contiguously in a first direction and in a second direction, such that two successive pairs in the first direction have at least one waveguide wall in common and such that two successive pairs in the second direction have at least one waveguide wall in common.

[0044] The invention may also relate to a waveguide array for transmitting a single polarization, comprising several rows (or slices) of waveguides, each row comprising power combiners, bent waveguides and straight sections, in which the straight waveguides of each row have sections as described according to the first or second embodiment. 03 / 21 / 2024

[0045] The invention may also relate to a waveguide network intended to transmit two polarizations, comprising at least one line (or slice) of waveguide intended to transmit a signal of first polarization and at least one second line (or slice) of waveguides intended to transmit a signal of second polarization, each line comprising power combiners, bent waveguides and straight sections, in which the straight waveguides of each line have sections as described according to the first or second embodiment. Brief description of the figures

[0046] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: • Figure 1 schematically illustrates a cross-sectional view of a waveguide according to a first embodiment. • Figure 2 schematically illustrates a cross-sectional view of a waveguide according to a first embodiment, here provided with a single groove. • Figure 3 schematically illustrates a cross-sectional view of a waveguide network according to the first embodiment. • Figure 4 schematically illustrates a cross-sectional view of a waveguide network according to a second embodiment. Example(s) of embodiment of the invention

[0047] Figure 1 illustrates the cross-section of a waveguide according to a first embodiment, substantially peanut-shaped. The waveguide comprises a core 100 produced by additive manufacturing, by RECTIFIED SHEET (RULE 91) ISA / EP example a metallic core, and a conductive coating 101 on an internal wall of this core.

[0048] The cross-section of the waveguide channel 10 is oval, not circular, and has a first axis of symmetry along the direction of greatest elongation x, as well as a second axis of symmetry along a direction y perpendicular to this direction of greatest elongation.

[0049] According to the direction of greatest elongation x, the channel 10 alternately comprises a first convex end 110, a concave connecting portion 111, and a second convex end 112. The dimension of the channel in the direction y perpendicular to said greatest elongation x is greater at said ends than in the connecting portion.

[0050] The connecting portion 11 comprises two concave portions 1110, 1111 facing each other. These concave portions form two grooves facing each other allowing certain transmission modes to be filtered. An additional groove 14 may be provided on one of the concave sections in order to reinforce this filtering, as illustrated in FIG. 2. It is also possible to provide more than one groove of this type in the channel.

[0051] The walls of the ridges 14 may be adapted to facilitate their additive manufacturing. For example, the angles between the walls of the ridges and the printing direction may be adapted to limit the overhanging portions. Alternatively or additionally, the ridges may include rounded portions to facilitate additive printing.

[0052] The contour of the ends 110, 112 may form an arc of at least 190°, preferably at least 210°. It is also possible to provide ends of a different shape.

[0053] The sections of the connecting portion 1110 extend the end sections with which they connect according to tangents, so as to produce a continuous and differentiable curve.

[0054] The wall of the waveguide illustrated in Figure 1 is substantially constant. An array is formed by juxtaposing several waveguides of this shape, as illustrated in Figure 3. Portions of the walls of adjacent waveguides are then shared.

[0055] The juxtaposition of waveguides according to figures 1 and 2 leaves areas not occupied by the elementary patterns of figure 1. These areas can be filled with metal, during additive manufacturing, and thus form areas for mechanical reinforcement and for heat dissipation. Since the mechanical rigidity and heat evaluation are reinforced thanks to these areas, it is possible to reduce the thickness of the waveguide walls in other places, and therefore to reduce the weight and size of the network.

[0056] Optional longitudinal openings 21 may be provided in these reinforcement zones 20, in order to cool the network and further lighten it.

[0057] The waveguide network advantageously comprises an even number of waveguides. The waveguides of the network are arranged two by two so as to form pairs of waveguides. Each pair of waveguides comprises a first waveguide 10 for propagating an electromagnetic wave having a first polarization P1 and a second waveguide 11 for propagating an electromagnetic wave having a second polarization P2. Thus, each pair of waveguides can support two polarizations. These pairs are characterized in that the waveguides that form them share a portion of wall.

[0058] It is also possible to provide a network of one of the types described in this description, but in which each waveguide transmits the same polarization.

[0059] The waveguide array is formed by creating lines of waveguides. A first line 120 is formed by juxtaposing waveguides in an x-direction perpendicular to their greatest elongation. A second line 121 is formed by juxtaposing other waveguides in the direction of their greatest elongation. The two lines are assembled by offsetting the second line 121 by half a waveguide width relative to the first line 120.

[0060] Figure 4 illustrates a waveguide network produced by additive manufacturing, according to a second embodiment. Each waveguide 10, 11 has a cross section substantially in the shape of a drop of water.

[0061] The waveguide comprises a core 100 produced by additive manufacturing, for example a metal core, and a conductive coating 101 on an internal wall of this core.

[0062] The cross-section of the waveguide channel 10 is oval, not circular, and has a single axis of symmetry along the direction of longest elongation x.

[0063] In the direction of longest elongation x, the channel 10 alternately comprises a first convex end 113, and a second end formed of two non-parallel walls 114, 115. These non-parallel walls meet. The non-parallel walls 114, 115 extend the first convex end 113 along two tangents.

[0064] In this example, the contour of the first convex end forms an arc of at least 180°. Other convex curves can be imagined.

[0065] Channel 10, 11 may be provided with a groove (not shown), or several grooves, on any portion of the channel, in order to filter certain modes of transmission.

[0066] The waveguides according to the first and second embodiments described may be straight or bent. It is also possible to provide combiners, for example Y or H combiners, with several branches of section as described.

[0067] The waveguide array is formed by creating rows of waveguides. A first row 130 is formed by juxtaposing waveguides in an x-direction perpendicular to their greatest elongation. A second row 131 is formed by juxtaposing other waveguides in the direction of their greatest elongation. The two rows are assembled head to tail, offsetting the second row 131 by half a waveguide width relative to the first row 130. This allows the non-parallel walls 114, 115 to be shared between waveguides of two rows.

[0068] The waveguide may comprise a third row 132 of waveguides juxtaposed in the x direction, and a fourth row 133 of waveguides juxtaposed and out of phase with respect to the third row by half the waveguide width. The second and third rows are adjacent, the waveguides being in contact via a portion of their convex first end wall.

[0069] The juxtaposition of water droplet-shaped waveguides leaves areas not occupied by the elementary patterns, particularly between lines 2 and 3. These areas can be filled with metal during additive manufacturing, thus forming areas of mechanical reinforcement and for heat dissipation. Since mechanical rigidity and heat dissipation are enhanced through these areas, it is possible to reduce the thickness of the waveguide walls in other locations, in order to reduce the weight and size of the network.

[0070] The present invention also relates to a dual-polarization antenna array 2 obtained by additive manufacturing and including a waveguide array 1 as described above as well as a plurality of radiating elements coupled to the pairs of waveguides.

[0071] In one embodiment, each radiating element is connected to a pair of waveguides 10, 11 so as to transmit or receive a dual-polarization signal (P1, P2), the first waveguide 10 of the pair propagating the first polarization P1 and the second waveguide 11 of the pair propagating the second polarization P2.

[0072] Additive manufacturing is particularly suitable for the production of such waveguide and antenna networks. Indeed, it allows for an optimized density of the different waveguide networks. Furthermore, it drastically reduces manufacturing time and cost. Indeed, the production of monolithic parts using additive manufacturing allows for the minimization of the number of parts that need to be assembled to obtain the final device. In some cases, this number of parts is equal to one and requires no assembly.

[0073] In one embodiment, the waveguide array 1 operates as a combiner / splitter and / or as a beamforming array. Typically, the waveguide array further comprises Y-junctions to operate as a combiner array.

[0074] In some embodiments, the waveguide and / or antenna array further comprises elements such as a septum, impedance matching elements, power combiners and / or dividers, passive filters.

[0075] The networks described are typically intended to operate in the X, Ku, Ka, QV, Ku / Ka and / or Ka / QV frequency bands.

Claims

Claims 1. Waveguide network (1) obtained by additive manufacturing comprising waveguides arranged two by two so as to form at least one pair of waveguides, each pair of waveguides comprising: a first waveguide channel (10), and a second waveguide channel (11); characterized in that the first and second channels comprise a non-circular oval cross-section with an axis of symmetry (x) and at least one non-rectilinear portion, and in that the first waveguide and the second waveguide have a common wall portion (100).

2. Network according to claim 1, wherein the first waveguide channel is intended to propagate a first polarization (P1) and wherein the second waveguide channel is intended to propagate a second polarization (P2).

3. Network according to one of the preceding claims, in which the first and second channels comprise a non-circular oval section with two axes of symmetry (x, y).

4. Network according to the preceding claim, in which said waveguide channels alternately comprise, along their largest dimension (x), a first convex end (110), a concave connecting portion (111), and a second convex end (112).

5. Network according to the preceding claim, in which the dimension of the channel (10, 11) in a direction (y) perpendicular to said largest dimension (x) is greater at said ends than in the connecting portion.

6. Network according to the preceding claim, in which said connecting portion comprises two concave segments facing each other.

7. Network according to the preceding claim, in which the outline of said ends forms an arc of a circle of at least 210°.

8. Network according to one of claims 6 or 7, in which a concave segment further comprises a groove (14).

9. Network according to one of the preceding claims, in which two internal walls of the first waveguide (10) and two internal walls of the second waveguide (11) comprise a groove (14).

10. Network according to one of claims 3 to 9, said waveguide channels having substantially a geometric peanut shape.

11. Network according to one of the preceding claims, comprising a first line (120) of waveguides juxtaposed in the direction (x) of their greatest elongation, and a second line (121) of waveguides juxtaposed in the direction of their greatest elongation, the second line being offset by half a waveguide length relative to the first line.

12. Network according to the preceding claim, in which the spaces between said channels (20) form solid reinforcement zones.

13. Network according to the preceding claim, in which the spaces between said channels form reinforcement zones (20) provided with openings (21).

14. Network according to claim 1, wherein said waveguide channels alternately comprise, along their largest dimension (x), a first convex end (113), and a second end formed by two non-parallel walls (114, 115).

15. A network according to claim 14, wherein said non-parallel walls (114, 115) meet.

16. Network according to one of claims 14 or 15, in which the contour of the first convex end (113) forms an arc of a circle of at least 180°.

17. Network according to one of claims 14 to 16, in which said non-parallel walls (114, 115) extend the first convex end along two tangents.

18. Network according to one of claims 14 to 17, in which each said channel (10, 11) comprises a groove.

19. Network according to one of claims 14 to 18, comprising a first line (130) of waveguides juxtaposed in a direction (x) perpendicular to their greatest elongation, and a second line (131) of waveguides juxtaposed in the direction of their greatest elongation, the two lines being head to tail, the second line being offset by half the width of the waveguide relative to the first line.

20. Network according to the preceding claim, comprising a third line (132) of waveguides juxtaposed in a direction (x) perpendicular to their greatest elongation, and a fourth line (133) of waveguides juxtaposed in the direction of their greatest elongation, the third line being juxtaposed to the second line.

21. A waveguide array according to any preceding claim further comprising Y junctions for functioning as a combiner array.

22. Dual polarization antenna array (2) obtained by additive manufacturing comprising: a waveguide array (1) according to one of the preceding claims, a plurality of radiating elements, each radiating element being coupled to the end of exactly one pair of waveguides of the array.

23. Antenna array (2) according to the preceding claim, the waveguide array (1) comprising at least eight waveguides and the pairs of waveguides being arranged contiguously in a first direction and in a second direction, such that two successive pairs in the first direction have at least one waveguide wall in common and such that two successive pairs in the second direction have at least one waveguide wall in common.

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