Waveguide array with circular cross-section

Abstract

A waveguide array (1) obtained by additive manufacturing, comprising an even number of waveguides arranged in pairs to form at least one waveguide pair, each waveguide pair comprising: a first waveguide channel (10) and a second waveguide channel (11); wherein the first channel and the second channel have a non-circular elliptical cross-section having an axis of symmetry (x) and at least one non-linear portion, and wherein the first waveguide and the second waveguide share a wall portion (100).

Description

TECHNICAL FIELD

[0001] The present invention relates to a waveguide array and to an antenna array comprising such a waveguide array. BACKGROUND

[0002] Radio frequency waveguide arrays are widely used in many fields of telecommunication, in particular satellite telecommunication.

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

[0004] Additive manufacturing of such devices offers the advantage of complex geometries that optimize the space occupied by the device and of manufacturing methods that require very few assembly steps, thus reducing manufacturing time and cost. However, to be viable, additive manufacturing also has certain constraints, in particular in terms of device geometry.

[0005] There is therefore a need for passive radio frequency devices that are optimized for compactness, minimization in terms of weight and have a geometry that is suitable for additive manufacturing.

[0006] There is also a need for alternative waveguide array geometries to offer designers greater design freedom.

[0007] Waveguide networks usually comprise a matrix arrangement of rectangular cross-section waveguides or a honeycomb arrangement of hexagonal cross-section waveguides. In these arrangements, each waveguide, except the waveguides at the edges of the array, shares all its walls with adjacent waveguides. This sharing of walls reduces the weight and the space occupation of the array.

[0008] Contrary to what one might intuitively think, these arrangements that share all walls do not always allow for an optimal ratio between the surface area of the channels and the surface area of the walls. This is because the walls of the waveguides must be thick enough to ensure the rigidity and the heat dissipation of the network. This significant thickness of all walls tends to make the network heavier and bulkier.

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

[0010] Networks formed by circular cross-section waveguides arranged in a matrix have also been designed. In this arrangement, each waveguide shares only very limited lengths of its contour, for example four points, with its neighboring waveguides. The ratio between the surface area of the channels and the surface area of the walls is therefore unfavorable. SUMMARY

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

[0012] It is another object of the present invention to provide a waveguide network that facilitates additive manufacturing.

[0013] Another object of the application is to provide a waveguide array limiting the number of assembly steps during manufacturing.

[0014] Another object of the application is to provide a waveguide array having optimized compactness.

[0015] Another object of the application is to provide a waveguide network lighter than in the prior art.

[0016] According to the application, these objects are achieved in particular by means of a waveguide network obtained by additive manufacturing, comprising waveguides arranged in pairs to form at least one waveguide pair, each waveguide pair comprising:

[0017] a first waveguide channel, and

[0018] a second waveguide channel;

[0019] the first and second channels comprising a non-circular elliptical cross-section having an axis of symmetry and at least one non-straight portion,

[0020] and the first and second waveguides having a common wall portion.

[0021] The elliptical cross-section is a cross-section formed by a closed differentiable curve having at least one axis of symmetry and more or less similar to an ellipse. For example, elliptical, egg-shaped, stadium-shaped and peanut-shaped morphologies are considered as elliptical in the present application.

[0022] The elliptical shape increases the common wall portion shared between adjacent waveguides compared to a network formed by waveguides having a circular cross-section, thus improving the ratio between wall surface area and channel surface area.

[0023] The elliptical shape also offers the advantage of generally being easier to produce by additive manufacturing compared to other shapes having more overhanging portions.

[0024] The elliptical shape cannot be perfectly juxtaposed on a plane without leaving gaps between them. These gaps, generally considered undesirable, are exploited in the present application by filling them at least partially to create locally thicker walls, thus reinforcing the rigidity of the device and improving heat dissipation. Other portions of the wall shared between these reinforced areas can thus be printed with a thinner thickness. Thus, contrary to what one might initially think, the imperfect juxtaposition of the waveguide channels having the claimed shape makes it possible to create reinforced zones that ultimately reduce the thickness of other walls, and thus reduce the weight and volume of the network compared to a network formed by waveguides having a rectangular or hexagonal cross-section in which all the walls are shared.

[0025] In variants, these reinforcement zones can be perforated with openings to dissipate heat and further reduce the weight of the network.

[0026] In a first embodiment, the first and second channels comprise a non-circular elliptical cross-section having two axes of symmetry.

[0027] The waveguide channel comprises alternately along its longest dimension a first convex end, a concave connection and a second convex end.

[0028] The connection can comprise two concave walls facing each other.

[0029] The dimension of the channel in a direction perpendicular to said longest dimension is greater at said ends than in the connection.

[0030] In this embodiment, the channel cross-section is thus substantially peanut-shaped.

[0031] The profile of the ends forms a circular arc of at least 190°, preferably at least 210°. The connection can be connected to the ends in a direction tangential to these circular arcs.

[0032] The concave walls of the concave connection can have ridges.

[0033] The two inner walls of the first waveguide and the two inner walls of the second waveguide can each comprise a ridge.

[0034] The network can comprise a first row (or sheet) of waveguides juxtaposed in their direction of maximum elongation and a second row (or sheet) of waveguides juxtaposed in their direction of maximum elongation, the second row being offset by half a waveguide length relative to the first row. The convex portions of each waveguide thus abut against the convex connections of the waveguides on the adjacent row.

[0035] In another embodiment, the waveguide channel has alternately along its longest dimension a first convex end and a second end formed by two non-parallel walls.

[0036] The waveguide channel then has a substantially drop shape.

[0037] The non-parallel walls meet to form the second end of the channel.

[0038] The profile of the first convex end can form a circular arc of at least 180°.

[0039] The non-parallel walls can cause the first convex end to extend along two tangents.

[0040] Each channel can have one or more ridges.

[0041] A network according to the second embodiment can comprise a first row of waveguides juxtaposed in a direction perpendicular to their maximum elongation and a second row of waveguides juxtaposed in their maximum elongation direction, the two rows being end-to-end, the second row being offset by half a waveguide width relative to the first row.

[0042] The network can comprise a third row of waveguides juxtaposed in a direction perpendicular to their maximum elongation and a fourth row of waveguides juxtaposed in their maximum elongation direction, the third row being juxtaposed with the second row.

[0043] The waveguide network can further comprise Y junctions for operating as a combiner network.

[0044] A dual polarized antenna array obtained by additive manufacturing can comprise a waveguide network as described above, and a plurality of radiating elements, each coupled to the end of exactly one pair of waveguides of the network.

[0045] A cross-section matching section can be provided between each waveguide and each radiating element.

[0046] A partition can be provided between each radiating element and the pair of waveguides.

[0047] Such an antenna array can comprise at least eight waveguides, wherein the pairs of waveguides are arranged consecutively in a first direction and in a second direction, such that two consecutive pairs in the first direction have at least one common waveguide wall, and such that two consecutive pairs in the second direction have at least one common waveguide wall.

[0048] The invention can also relate to a waveguide network for transmitting a single polarization comprising several rows (or tiles) of waveguides, each row comprising a power combiner, a curved waveguide and a straight section, wherein the straight waveguides of each row have a cross-section as described in the first embodiment or in the second embodiment.

[0049] The invention can also relate to a waveguide network for transmitting two polarizations comprising at least one row (or tile) of waveguides for transmitting a first polarization signal and at least one second row (or tile) of waveguides for transmitting a second polarization signal, each row comprising a power combiner, a curved waveguide and a straight section, wherein the straight waveguides of each row have a cross-section as described in the first embodiment or in the second embodiment. BRIEF DESCRIPTION OF DRAWINGS

[0050] Examples of embodiments of the invention are illustrated in the description given with reference to the drawings, in which:

[0051] · Figure 1 A cross-section of a waveguide according to the first embodiment is schematically illustrated.

[0052] · Figure 2 A cross-section of a waveguide according to the first embodiment is schematically illustrated, here provided with a single ridge.

[0053] · Figure 3 A cross-section of a waveguide network according to a first embodiment is schematically shown.

[0054] · Figure 4 A cross-section of a waveguide network according to a second embodiment is schematically shown. DETAILED DESCRIPTION

[0055] Figure 1 A cross-section of a waveguide according to a first embodiment is shown, which is substantially peanut-shaped. The waveguide comprises a core 100, for example a metallic core, produced by additive manufacturing, and an electrically conductive coating 101 on the inner wall of the core.

[0056] The cross-section of the waveguide channel 10 is elliptical non-circular and has a first axis of symmetry in the direction of maximum elongation x and a second axis of symmetry in the direction y perpendicular to the direction of maximum elongation.

[0057] In the direction of maximum elongation x, the channel 10 has alternately a first convex end 110, a concave connection 111 and a second convex end 112. The dimension of the channel in the direction y perpendicular to the direction of maximum elongation x is greater at the ends than in the connections.

[0058] The connection 11 has two concave parts 1110, 1111 facing each other. These concave parts form two ridges facing each other, thus enabling certain transmission modes to be filtered. As Figure 2 shown, an additional ridge 14 can be provided on one of the concave sections to enhance the filtering. More than one ridge of this type can also be provided in the channel.

[0059] The walls of the ridges 14 can be adapted to facilitate their additive manufacturing. For example, the angle between the walls of the ridges and the printing direction can be adapted to limit overhangs. Alternatively or additionally, the ridges can comprise rounded parts to facilitate additive printing.

[0060] The profile of the ends 110, 112 can form an arc of at least 190°, preferably at least 210°. Ends of different shapes can also be provided.

[0061] The cross-section of the connections 1110 extends the cross-section of the ends they connect along a tangent, so as to form a continuous and differentiable curve.

[0062] Figure 1 The walls of the waveguides shown are substantially constant. A network is formed by juxtaposing several waveguides of this shape, as Figure 3 shown. A portion of the walls of adjacent waveguides is then common.

[0063] According to Figure 1 and Figure 2The juxtaposition of the waveguides leaves areas not occupied by Figure 1 These areas can be filled with metal during additive manufacturing, thereby forming areas of mechanical reinforcement and for heat dissipation. Since these areas reinforce mechanical rigidity and heat dissipation, it is possible to reduce the thickness of the waveguide walls in other areas, thereby reducing the weight and size of the network.

[0064] Optional longitudinal openings 21 can be provided in these reinforcement zones 20 to cool the network and make it lighter.

[0065] The waveguide network advantageously comprises an even number of waveguides. The waveguides of the network are arranged in pairs to form waveguide pairs. Each waveguide pair comprises a first waveguide 10 for propagating electromagnetic waves having a first polarization PI and a second waveguide 11 for propagating electromagnetic waves having a second polarization P2. Each waveguide pair can thus support two polarizations. The pairs are characterized in that the waveguides forming them share a portion of a wall.

[0066] It is also possible to provide a network of the type described in the present specification, but in which each waveguide transmits the same polarization.

[0067] The waveguide network is formed by creating rows of waveguides. A first row 120 is formed by juxtaposing waveguides in a direction x perpendicular to their maximum elongation. A second row 121 is formed by juxtaposing other waveguides in their maximum elongation direction. The two rows are assembled by shifting the second row 121 relative to the first row 120 by half a waveguide width.

[0068] Figure 4 A waveguide network produced by additive manufacturing is shown according to a second embodiment. Each waveguide 10, 11 has a substantially drop-shaped cross-section.

[0069] The waveguide comprises a core 100 produced by additive manufacturing, for example a metal core, and an electrically conductive coating 101 on the inner wall of the core.

[0070] The cross-section of the waveguide channel 10 is elliptical non-circular and has a single axis of symmetry in the maximum elongation direction x.

[0071] In the maximum elongation direction x, the channel 10 alternately has a first convex end 113 and a second end formed by two non-parallel walls 114, 115. The non-parallel walls meet. The non-parallel walls 114, 115 cause the first convex end 113 to extend along two tangents.

[0072] In this example, the profile of the first convex end forms a circular arc of at least 180°. Other convex curves can be envisaged.

[0073] The channels 10, 11 can be provided with one ridge (not shown) or several ridges on any portion of the channel, in order to filter certain transmission modes.

[0074] The waveguides according to the first and second embodiments described can be straight or curved. Combiners with several branches of cross-section as described, for example Y or H combiners, can also be provided.

[0075] A waveguide network is formed by creating rows of waveguides. A first row 130 is formed by juxtaposing waveguides in a direction x perpendicular to their maximum elongation. A second row 131 is formed by juxtaposing other waveguides in their maximum elongation direction. The two rows are assembled end to end so that the second row 131 is shifted by half a waveguide width with respect to the first row 130. This enables non-parallel walls 114, 115 to be shared between the waveguides of the two rows.

[0076] The waveguides can comprise a third row 132 of waveguides juxtaposed in the x direction and a fourth row 133 of waveguides juxtaposed and shifted by half a waveguide width with respect to the third row. The second and third rows are adjacent, the waveguides contacting via a portion of their first convex end wall.

[0077] The juxtaposition of drop-shaped waveguides leaves areas not occupied by the elementary pattern, in particular between row 2 and row 3. These areas can be filled with metal during additive manufacturing, thereby forming areas of mechanical reinforcement and for heat dissipation. Since these areas reinforce mechanical rigidity and heat dissipation, it is possible to reduce the thickness of the waveguide walls in other areas, thereby reducing the weight and size of the network.

[0078] The invention also relates to a dual-polarized antenna array 2 obtained by additive manufacturing, comprising a waveguide network 1 as described above and a plurality of radiating elements coupled to pairs of waveguides.

[0079] In one embodiment, each radiating element is connected to a pair 10, 11 of waveguides to emit or receive dual-polarized signals (P1, P2), the first waveguide 10 in the pair propagating a first polarization P1 and the second waveguide 11 in the pair propagating a second polarization P2.

[0080] Additive manufacturing is particularly well suited to producing such waveguide networks and antenna arrays. It makes it possible to optimize the density of the various waveguide networks. In addition, it also greatly reduces manufacturing time and cost. The use of additive manufacturing to produce monolithic components minimizes the number of components that need to be assembled to obtain the final device. In some cases, this number of components is equal to one and no assembly is required.

[0081] In one embodiment, the waveguide network 1 operates as a combiner / splitter and / or a beamforming network. Typically, the waveguide network also comprises Y junctions for operating as a combiner network.

[0082] In some embodiments, the waveguide network and / or antenna array further includes elements such as septums, impedance matching elements, power combiners and / or splitters, and passive filters.

[0083] The networks described are generally intended to operate in the X, Ku, Ka, QV, Ku / Ka, and / or Ka / QV bands.

Claims

1. A waveguide network (1) obtained by additive manufacturing, comprising waveguides arranged in pairs 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 - said first channel and said second channel comprise a non-circular elliptical cross section having a symmetry axis (x) and at least one non-straight portion, - and said first waveguide and said second waveguide have a common wall portion (100).

2. The network of claim 1, wherein, - said first waveguide channel is intended to propagate a first polarization (PI), and wherein said second waveguide channel is intended to propagate a second polarization (P2).

3. Network according to one of the preceding claims, wherein, - said first channel and said second channel comprise a non-circular elliptical cross section having two symmetry axes (x, y).

4. The network of the preceding claim, wherein, - said waveguide channel comprises alternately along its longest dimension (x) a first convex end (110), a concave connection portion (111) and a second convex end (112).

5. The network of the preceding claim, wherein, - said channels (10, 11) have a dimension in a direction (y) perpendicular to said longest dimension (x) which is greater at said ends than in said connection portions.

6. The network of the preceding claim, wherein, - said connection portion comprises two concave segments facing each other.

7. The network of the preceding claim, wherein, - the profile of said ends forms an arc of at least 210°.

8. The network of one of claims 6 or 7, wherein, - the concave segments further comprise a ridge (14).

9. Network according to one of the preceding claims, wherein, - the two inner walls of said first waveguide (10) and the two inner walls of said second waveguide (11) comprise a ridge (14).

10. The network of one of claims 3 to 9, wherein, - said waveguide channel has a substantially peanut-shaped geometry.

11. The network according to one of the preceding claims, comprising a first row (120) of waveguides juxtaposed in the direction of maximum elongation (x) of the waveguides and a second row (121) of waveguides juxtaposed in the direction of maximum elongation of the waveguides, the second row being offset by half a waveguide length with respect to the first row.

12. The network of the preceding claim, wherein, - the space between said channels (20) forms a solid reinforcement zone.

13. The network of the preceding claim, wherein, - the space between said channels forms a reinforcement zone (20) provided with openings (21).

14. The network of claim 1, wherein, - said waveguide channel comprises alternately along its longest dimension (x) a first convex end (113) and a second end formed by two non-parallel walls (114, 115).

15. The network of claim 14, wherein, - said non-parallel walls (114, 115) intersect.

16. The network of one of claims 14 or 15, wherein, - the profile of said first convex end (113) forms an arc of at least 180°.

17. The network of one of claims 14 to 16, wherein, - said non-parallel walls (114, 115) cause said first convex end to extend along two tangents.

18. The network of one of claims 14 to 17, wherein, - each of said channels (10, 11) comprises a ridge.

19. The network according to one of claims 14 to 18, comprising a first row (130) of waveguides juxtaposed in a direction (x) perpendicular to the maximum elongation of the waveguides and a second row (131) of waveguides juxtaposed in the direction of maximum elongation of the waveguides, the two rows being end to end, the second row being offset by half a waveguide width with respect to the first row.

20. The network according to the preceding claim, comprising a third row (132) of waveguides juxtaposed in a direction (x) perpendicular to the maximum elongation of the waveguides and a fourth row (133) of waveguides juxtaposed in the direction of maximum elongation of the waveguides, the third row being juxtaposed with the second row.

21. The waveguide network according to one of the preceding claims, further comprising Y-junctions for operating as combiner networks.

22. A dual polarized antenna array (2) obtained by additive manufacturing, comprising: a waveguide network (1) according to one of the preceding claims, a plurality of radiating elements, each coupled to the end of exactly one waveguide pair of the network.

23. The antenna array (2) according to the preceding claim, the waveguide network (1) comprising at least eight waveguides, and the waveguide pairs being arranged consecutively in a first direction and in a second direction, such that two consecutive pairs in the first direction have at least one common waveguide wall, and such that two consecutive pairs in the second direction have at least one common waveguide wall.

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