Method for the additive manufacture of an antenna array

Abstract

The present invention relates to a method for manufacturing an antenna array (1000), the method comprising the following steps: additively manufacturing a first layer (1) on a manufacture support (S) in a manufacture direction (z), the first layer (1) comprising a plurality of radiating elements (10); manufacturing a second layer (2) on top of the first layer (1) in the manufacture direction (z), the second layer (2) comprising a first vertical beamforming network (20) coupled to the plurality of radiating elements (10), characterised in that the first vertical beamforming network (20) is entirely supported by the first layer (1) during its additive manufacture. The invention also relates to an antenna array (1000) obtained using the above method.

Description

Additive manufacturing process for an antenna array technical field

[0001] The present invention relates to an additive manufacturing process for an antenna array and an antenna array manufactured according to this process. State of the art

[0002] Additive manufacturing of radio frequency components, particularly passive components, has recently gained popularity. The various additive manufacturing processes make it possible to obtain lighter and less expensive components, and therefore more attractive to market players, especially in the space sector where component weight is a major concern.

[0003] Additive manufacturing processes, however, require the development of sophisticated 3D printing strategies, particularly due to the difficulty of printing overhanging sections. During 3D printing, successive layers are placed one on top of the other. These layers are supported only by the preceding layers, which, when overhanging sections are present, can generate stresses that make manufacturing complex, or even impossible, without the aid of external supports. The use of external supports, generally manufactured simultaneously with the device itself, is not advantageous from an economic or device optimization standpoint, as such supports must be removed manually after printing or contribute significantly to the final weight of the device.

[0004] It is also known to adapt the orientation of the printed part in order to minimize the number of overhanging portions during STO12-148-PCT manufacturing, or even adapting the design to reduce constraints by tilting certain portions of the part relative to the printing direction.

[0005] These drawbacks are obviously multiplied when manufacturing devices with a large number of cantilevered sections. Some radio frequency devices, such as antenna arrays, can contain dozens or even hundreds of individual antennas, each of which itself has several cantilevered walls or elements, further increasing the number of constraints to consider during printing. The proliferation of auxiliary support structures, sometimes located in hard-to-reach places, makes their use very expensive, if not impossible. Brief summary of the invention

[0006] One aim of the present invention is to propose an additive manufacturing method for antenna arrays free from the limitations present in the prior art.

[0007] Another objective of the present invention is to propose an additive manufacturing process for antenna arrays that allows limiting, or even eliminating, the use of external additive manufacturing supports.

[0008] According to the invention, these objectives are achieved in particular by means of a method for manufacturing an antenna array comprising the following steps: additively fabricating a first layer on a fabrication support along a fabrication direction, the first layer comprising a plurality of radiating elements; fabricating a second layer above the first layer along the fabrication direction, the second layer comprising a STO12-148-PCT first vertical beamforming array coupled to the plurality of radiating elements, characterized in that the first vertical beamforming array is fully supported by the first layer during its additive manufacturing.

[0009] According to one embodiment, a maximum area of ​​the first vertical beamforming array measured in a plane orthogonal to the manufacturing direction is less than or equal to a minimum area of ​​the first layer measured in a plane orthogonal to the manufacturing direction.

[0010] According to one embodiment, the process according to the invention further comprises the following step: additively manufacturing a third layer on top of the second layer, the third layer comprising a second vertical beamforming array coupled to the first vertical beamforming array, the second vertical beamforming array being fully supported by the second layer during its additive manufacturing.

[0011] A maximum area of ​​the second vertical beamforming array measured in a plane orthogonal to the manufacturing direction may be less than or equal to a minimum area of ​​the second layer measured in a plane orthogonal to the manufacturing direction.

[0012] A greater number of such vertical beamforming arrays can thus be fabricated by being supported by the preceding layer. It is therefore possible to fabricate a multi-layered antenna array in a pyramidal fashion, meaning that the footprint (i.e., the maximum surface area) of each vertical array is smaller than the footprint of the preceding layer that supports it. STO12-148-PCT

[0013] According to one embodiment, the radiating elements are arranged contiguously along a first direction so as to form a one-dimensional network.

[0014] Additionally, the radiating elements can be arranged contiguously along a second direction to form a two-dimensional array. The radiating elements thus form a two-dimensional matrix in a plane perpendicular to the manufacturing direction.

[0015] According to one embodiment, each antenna in the antenna array is dual-polarized, and each radiating element includes a stepped septum for combining / splitting two wave propagation modes within the radiating element. Each septum comprises portions parallel to the additive manufacturing direction and portions inclined at an angle α to the additive manufacturing direction, the angle α being between 30° and 60°, preferably between 40° and 50°.

[0016] According to one embodiment, the first vertical beamforming array comprises a plurality of waveguides, the walls of the waveguides being either parallel to the manufacturing direction or inclined with respect to the manufacturing direction at an angle P between 30° and 60°, preferably between 40° and 50°.

[0017] When the antenna array includes the second vertical beamforming array coupled to the first, the second vertical array may also include a plurality of waveguides, the walls of the waveguides being either parallel to the direction of manufacture, or inclined with respect to the direction of manufacture at an angle between 30° and 60°, preferably between 40° and 50°.

[0018] According to one embodiment, the process according to the invention comprises a manufacturing and / or coupling step of a first network STO12-148-PCT horizontal beamforming to the first or second vertical beamforming array, the first horizontal beamforming array allowing two radiating elements arranged contiguously along the second direction to be coupled.

[0019] Additionally, each antenna in the array can be dual-polarized. In addition to the first horizontal beamforming array for propagating a first polarization, the method according to the invention may include a step of manufacturing and / or coupling a second horizontal beamforming array to the first or second vertical beamforming array, the second horizontal beamforming array propagating a second polarization orthogonal to the first polarization.

[0020] According to an advantageous embodiment, the additive manufacturing steps are carried out by powder bed fusion (for example SLM for "selective laser melting" in Anglo-Saxon terminology).

[0021] According to one embodiment, the antenna array is made monolithically, for example without the need for additional fixing steps between the elements made by additive manufacturing.

[0022] According to the invention, these goals are achieved in particular by means of an antenna array obtained by the antenna array manufacturing process described above. Brief description of the figures

[0023] Examples of implementation of the invention are given in the description illustrated by the accompanying figures, in which: [Fig. 1] Figure 1 illustrates a cross-sectional view of a two-layer antenna array printed on a manufacturing substrate. STO12-148-PCT [Fig. 2] Figure 2 illustrates a cross-sectional view of a three-layer antenna array printed on a manufacturing substrate. • [Fig. 3] Figure 3 illustrates a perspective view of a one-dimensional, three-layer antenna array printed on a manufacturing substrate. • [Fig. 4] Figure 4 illustrates a perspective view of a two-dimensional, three-layer antenna array printed on a manufacturing substrate. • [Fig. 5] Figure 5 illustrates a cross-sectional view of radiating elements equipped with septa. • [Fig. 6] Figure 6 illustrates a cross-sectional view of an antenna array whose radiating elements are equipped with septa. • [Fig. 7] Figure 7 illustrates a perspective view of a two-dimensional, three-layer, dual-polarized antenna array printed on a manufacturing substrate. Example(s) of an embodiment of the invention

[0024] The present invention relates to a method for the additive manufacturing of an antenna array. An antenna array is a set of separate antennas fed in such a way that the phase shift between any two antennas is fixed. In the context of the present invention, an antenna array extends from a radiating end, generally intended for transmitting into or receiving from free space, to a coupling end, typically intended for coupling to electronic equipment such as a PCB. Several passive radio frequency components, such as waveguides, can be arranged between these two ends. STO12-148-PCT filters, power combiners / dividers, various impedance matching elements, etc.

[0025] The terms "additive manufacturing", "3D printing" and "printing" are used interchangeably throughout this text.

[0026] In one aspect, the present invention proposes an additive manufacturing process for a self-supporting, multi-layered antenna array. Each 3D-printed layer serves as a support for the next. The term "layer" here refers to a "stage" or "position" within the antenna array, and not to an additive manufacturing layer as defined by the layer of material deposited during a pass of the additive manufacturing device. The "layers" of the present invention comprise structural radio frequency elements of the array (e.g., radiating elements, distribution network, etc.).

[0027] According to the invention, and as illustrated in Figure 1, a first layer 1 is additively fabricated on a build platform S along a build direction z. This first layer 1 of the antenna array comprises a plurality of radiating elements 10 whose function is to radiate electromagnetic energy into free space in transmission and / or to receive electromagnetic energy from free space in reception. The printing direction z corresponds to the direction orthogonal to the plane in which the material is deposited during additive manufacturing. The build platform S (also called the build platform or build plate) is an external support onto which the antenna array is printed. At the end of the antenna array fabrication process, the array is detached from the build platform S.

[0028] In a second step, a second layer 2 is additively fabricated on top of the first layer 1 along the fabrication direction z. The second layer 2 comprises a first vertical beamforming array 20 coupled to the plurality of radiating elements 10. STO12-148-PCT

[0029] A beamforming array (also called a spatial filtering array or pathforming array) is an array of combining electromagnetic waves in the antenna array so that the waves interfere constructively or destructively depending on the directions.

[0030] The first vertical beamforming array 20 is coupled to the plurality of radiating elements 10. In this way, the first array 20 can feed the radiating elements 10 during transmission and, conversely, be fed by the radiating elements 10 during reception. On the other hand, the first array 20 may include a coupling port allowing it to be coupled to electronic antenna components or to another coupling array.

[0031] In order to enable additive manufacturing of the antenna array while minimizing the use of external support structures (printed during the manufacturing of the array and / or additionally arranged to support certain portions of the array), the first vertical beamforming array 20 is fully supported by the first layer 1 during the second stage.

[0032] In other words, the footprint of the first vertical beamforming array 20 is smaller than the footprint of the first layer 1 so that the entire first array 20 is supported by the first layer 1. The footprint here refers to the maximum surface area of ​​the first array 20 measured in a plane orthogonal to the manufacturing direction z. The antenna array 1000 is thus manufactured in the manner of a pyramid.

[0033] Thus, the first layer 1 acts as a natural support for the first network 20 and therefore does not need to be removed after the manufacture of the second layer 2.

[0034] According to one embodiment, a maximum surface area of ​​the first vertical beamforming array 20 measured in a plane STO12-148-PCT orthogonal to the manufacturing direction z is less than or equal to a minimum area of ​​the first layer 1 measured in a plane orthogonal to the manufacturing direction z. In this way, the support function of the first layer 1 is improved since the area of ​​the first network 20 is less than that of the first layer 1.

[0035] As illustrated in Figure 3, the process may include an additive manufacturing step of a third layer 3 above the second layer 2. The third layer 3 comprises a second vertical beamforming array 30 coupled to the first vertical beamforming array 20. Thus, this second array 30 feeds the first array 20 for transmission and is fed by it for reception. According to this embodiment, the second layer 2 serves as a natural support for the second vertical beamforming array 30.

[0036] Similarly, the process may include the additive manufacturing of an arbitrary number of additional layers including, for example, coupling networks as above, such that each additional network is fully supported by the previous layer.

[0037] As before, a maximum area of ​​the second vertical beamforming array 30 measured in a plane orthogonal to the manufacturing direction z can be less than or equal to a minimum area of ​​the second layer 2 measured in a plane orthogonal to the manufacturing direction z so as to improve the support function of the second layer 2.

[0038] As illustrated in Figure 3, the 10 radiating elements can be arranged contiguously along a first direction x. The resulting 1000 antenna array is thus one-dimensional. This means that if one mentally associates the 1000 antenna array with a matrix, then the matrix has only one row and a number of columns equal to the number of 10 radiating elements. STO12-148-PCT

[0039] According to this embodiment, the footprint of the first layer 1 along the x direction is larger than the footprint of the first vertical beamforming array 20, so that the first layer 1 fully supports this first array 20.

[0040] Alternatively, and as illustrated in Figure 4, the radiating elements can be arranged contiguously along both the first x-direction and a second y-direction to form a two-dimensional array. If we mentally associate the antenna array with a matrix, then this matrix has several rows and a number of columns equal to the number of radiating elements, 10.

[0041] According to this embodiment, the footprint of the first layer 1 both in the x direction and also in the y direction is larger than the footprint of the first vertical beamforming array 20, so that the first layer 1 fully supports this first array 20.

[0042] It is thus possible to print antenna arrays 1000 comprising several dozen, or even several hundred, radiating elements 10, whose weight, and therefore printing constraints, can become significant, while avoiding the use of very numerous auxiliary manufacturing supports, e.g. in each radiating element 10.

[0043] According to one embodiment, each antenna in the antenna array 1000 is dual-polarized, i.e., each antenna can propagate two orthogonal polarizations. To this end, each radiating element 10 includes a stepped septum 100 which allows the two modes propagated by the radiating element 10 in question to be divided and / or combined.

[0044] Typically, stepped septa include 90° steps, creating significant cantilevered sections that require a support structure if they are to be additively fabricated along the z-direction. Thus, the geometric complexity of these antenna arrays STO12-148-PCT Including such septa generally constrains additive manufacturing by starting with the end intended to be coupled to the electronics and finishing with the radiating elements. This orientation limits the number of supports in hard-to-reach areas of the array; however, it introduces the need for additional supports due to the "flared" nature of the antenna array. Indeed, the surface area of ​​the array's end at the level of the radiating elements (front zone) is generally larger than the surface area at the level of the electronics (rear zone). This difference in surface area naturally results in overhanging sections requiring support during printing.

[0045] Surprisingly, the present invention proposes to manufacture septa whose stair steps are inclined with respect to the manufacturing direction z.

[0046] As illustrated in Figure 5, each radiant element 10 can be provided with a septum 100 comprising a succession of stair steps, each comprising a portion parallel 101 to the manufacturing direction z and a portion inclined 102 at an angle α with respect to the manufacturing direction z. Thus, the cantilevered portions are limited and it is no longer necessary to use support structures for printing.

[0047] According to one embodiment, the angle a is between 30° and 60° relative to the manufacturing direction, or preferably between 40° and 50° with an optimal value at 45°.

[0048] This embodiment proves particularly useful for manufacturing antenna arrays comprising a large number of radiating elements 10. Indeed, if each radiating element 10 is equipped with a septum 100, conventional additive manufacturing would require an equivalent number of external support structures (one to support each step of each septum). Such supports are then extremely tedious and costly to remove after printing, which is why the methods STO12-148-PCT Traditional additive manufacturing methods consist of manufacturing such networks by starting with printing the end opposite the radiating elements and ending with the radiating elements.

[0049] To further limit the presence of cantilevered sections in the antenna array, one or more of the different waveguides composing the first vertical array 20 can be inclined at an angle P with respect to the manufacturing direction z. This means that the walls of these waveguides are oriented during manufacturing in a direction forming an angle with the manufacturing direction z. This angle P is between 30° and 60°, preferably between 40° and 50°, with 45° being the optimal angle minimizing sagging stresses.

[0050] As illustrated in Figure 6, some waveguides forming part of the first vertical array 20 are oriented at an angle P relative to the manufacturing direction of between 30° and 60°. Other portions, in particular the coupling portions to the radiating elements 10 or the coupling portions between the first vertical array 20 and the second vertical array 30, are manufactured vertically, that is, parallel to the manufacturing direction z. It is thus possible to manufacture an antenna array 1000 with a minimum of cantilevered portions.

[0051] Such an inclination of the walls of the waveguides of the second vertical array 30 can also be advantageous. As illustrated in Figure 6, these walls can thus be inclined at an angle with respect to the vertical direction z. This angle is also between 30° and 60°, preferably between 40° and 50°, with 45° constituting the optimal angle minimizing sagging stresses.

[0052] It is thus possible to obtain a pyramid-shaped array of 1000 level antennas, each vertical array having waveguides inclined so as to converge gradually. This optimal shape STO12-148-PCT This allows for a self-supporting network during manufacturing with a minimum of cantilevered sections.

[0053] Figure 7 illustrates a 1000 dual-polarized antenna array. The second vertical beamforming array 30 comprises a plurality of vertical sub-arrays aligned along the y-direction. Each of these sub-arrays feeds a line of radial elements 10 aligned along the x-direction. In addition, each of these sub-arrays includes two input ports, one for each polarization.

[0054] When the antenna array 1000 is two-dimensional, that is, when it comprises contiguous radiating elements 10 in both the first x direction and the second y direction, it is advantageous to be able to couple two adjacent radiating elements 10 along the second y direction in addition to coupling along the first x direction. Thus, according to an embodiment not shown, the present manufacturing process includes a step of manufacturing and / or coupling a first horizontal beamforming array that allows coupling two contiguous radiating elements 10 along the second y direction. This first horizontal array can be coupled to the first or second vertical array 20, 30, or to any other additional vertical array.

[0055] When the grating is not only two-dimensional but also doubly polarized, it is also advantageous to be able to couple contiguous radiating elements 10 along the second y-direction for each of the two polarizations. Thus, according to an embodiment not shown, the present manufacturing process includes a step of manufacturing and / or coupling a first and a second horizontal beamforming grating. The first horizontal grating allows the coupling of two contiguous radiating elements 10 along the second y-direction in order to propagate a first polarization, and the second horizontal grating allows the coupling of these two radiating elements 10 in order to propagate a second polarization. These first and second horizontal beamforming gratings STO12-148-PCT beams can be coupled to the first or second vertical array 20, 30, or to any other additional vertical array.

[0056] Advantageously, the first and / or second horizontal beamforming array can also be manufactured by 3D printing following the other antenna array elements. However, it is also possible to manufacture it using another process and then attach it to the antenna array by welding, brazing, gluing, screwing, or any other fastening method.

[0057] In an advantageous embodiment, the additive manufacturing steps are performed by selective laser melting (SLM). However, other advantageous additive manufacturing processes include metal binder jetting, electron beam melting (EBM), direct metal laser sintering (DMLS), and directed energy deposition (DED). This list of processes is provided by way of example and does not limit the 3D printing techniques that can be used to implement the invention.

[0058] According to an advantageous embodiment, all the elements of the 1000 antenna array are made monolithically, meaning that no assembly is required after the 3D printing stage. This makes it possible to avoid using flanges to fix the elements to each other and therefore obtain a lighter and less bulky device.

[0059] The present invention also relates to an antenna array obtained by the process described above. STO12-148-PCT Reference numbers used in the figures 1 First layer 10 Radiant Element 100 Septum 101 Parallel Portion 102 Sloping Portion 1000 Antenna Network 2 Second layer 20 First vertical beamforming array 3 Third layer 30 Second vertical beamforming array S Manufacturing support z Manufacturing direction X First direction y Second direction STO12-148-PCT

Claims

Demands 1. Method for manufacturing an antenna array (1000) comprising the following steps: additively manufacturing a first layer (1) on a manufacturing support (S) along a manufacturing direction (z), the first layer (1) comprising a plurality of radiating elements (10), manufacturing a second layer (2) above the first layer (1) along the manufacturing direction (z), the second layer (2) comprising a first vertical beamforming array (20) coupled to the plurality of radiating elements (10), characterized in that the first vertical beamforming array (20) is entirely supported by the first layer (1) during its additive manufacturing.

2. Method according to claim 1, wherein a maximum area of ​​the first vertical beam-forming array (20) measured in a plane orthogonal to the manufacturing direction (z) is less than or equal to a minimum area of ​​the first layer (1) measured in a plane orthogonal to the manufacturing direction (z).

3. A method according to any one of the preceding claims, further comprising the following step: additively manufacturing a third layer (3) above the second layer (2), the third layer (3) comprising a second vertical beamforming array (30) coupled to the first vertical beamforming array (20), the second vertical beamforming array (30) being fully supported by the second layer (2) during its additive manufacturing.

4. A method according to the preceding claim wherein a maximum surface area of ​​the second vertical beam-forming array (30) measured in a plane orthogonal to the manufacturing direction (z) is STO12-148-PCT less than or equal to a minimum area of ​​the second layer (2) measured in a plane orthogonal to the manufacturing direction (z).

5. Method according to any one of the preceding claims, the radiating elements (10) being arranged contiguously along a first direction (x) so as to form a one-dimensional lattice.

6. Method according to the preceding claim, the radiant elements (10) being further arranged contiguously along a second direction (y) so as to form a two-dimensional network.

7. A method according to any one of the preceding claims, each antenna of the antenna array (1000) being dual-polarized and each radiating element (10) comprising a stepped septum (100) allowing two propagation modes of a wave to be combined / divided in the radiating element (10), the septum (100) comprising portions parallel (101) to the additive manufacturing direction and portions inclined (102) at an angle (a) with respect to the additive manufacturing direction, the angle (a) being between 30° and 60°, preferably between 40° and 50°.

8. A method according to any one of the preceding claims, the first vertical beamforming array (20) comprising a plurality of waveguides, the walls of the waveguides being either parallel to the direction of manufacture, or inclined with respect to the direction of manufacture at an angle (P) between 30° and 60°, preferably between 40° and 50°.

9. Method according to claim 3, the second vertical beamforming array (30) comprising a plurality of waveguides, the walls of the waveguides being either parallel to the direction of manufacture, or inclined with respect to the direction of manufacture at an angle (y) between 30° and 60°, preferably between 40° and 50°. STO12-148-PCT 10. Method according to claim 6, comprising a manufacturing and / or coupling step of a first horizontal beamforming array to the first or second vertical beamforming array (30), the first horizontal beamforming array allowing the coupling of two radiant elements (10) arranged contiguously along the second direction (y).

11. Method according to the preceding claim, each antenna of the antenna array (1000) being dual-polarized, the first horizontal beamforming array enabling the propagation of a first polarization, the method comprising a step of manufacturing and / or coupling a second horizontal beamforming array to the first or second vertical beamforming array (20; 30), the second horizontal beamforming array enabling the propagation of a second polarization orthogonal to the first polarization.

12. A method according to any one of the preceding claims, wherein the additive manufacturing steps are carried out by powder bed fusion.

13. Method according to any one of the preceding claims, the antenna array (1000) being made monolithically.

14. Antenna array (1000) obtained by the manufacturing process according to one of the preceding claims. STO12-148-PCT

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