FLEXIBLE WAVEGUIDE DEVICE AND METHOD FOR MANUFACTURING SUCH A DEVICE

Abstract

The invention concerns a flexible waveguide device (10), of the bellows type, for guiding a radio frequency signal at a given frequency range. The device comprises: a core (12) comprising outer and inner side walls (14a, 14b), the inner walls (14b) delimiting a waveguide channel (16); two fixing flanges (18a, 18b) connected to or integral with respective ends of the core (12), and at least one flexible corrugated portion (20) formed on a part of the outer side walls (14a) of the core (12) and comprising a plurality of circumferential ribs (22) adjacent to each other. Each rib (22) is devoid of corrugation along its circumference. The invention also relates to a method of manufacturing the flexible waveguide device.

Claims

1. Method of manufacturing a flexible waveguide device (10), of the bellows type, comprising a core (12) through which a channel (16) passes in order to guide a radio frequency signal at a given frequency. The method comprises the following steps: making by additive manufacturing a mandrel (30) having an outer shell comprising a corrugated portion (20) having a plurality of adjacent circumferential ribs (22), depositing a metal layer (25) on the outer shell of the mandrel (30) by electroforming to form the core (12) of the device (10), and removing the mandrel (30) from the electroformed metal layer to define the channel (16).

2. Method according to claim 1, wherein the electroformed metal layer has a homogeneous thickness between 0.05 to 5 mm and preferably between 0.1 to 0.5 mm.

3. Method according to any preceding claim, wherein the mandrel (30) is manufactured so as to obtain a hollow mandrel.

4. Method according to any preceding claim, wherein the mandrel (30) is dissolved away with a dissolving solution.

5. Method according to any preceding claim, wherein the mandrel (30) and the metal layer (25) formed on the outer shell of the mandrel are immersed in a solvent bath.

6. Method according to any preceding claim, wherein two fixing flanges (18a, 18b) are fixed to the respective ends of the core (129, preferably by brazing.

7. Method according to any of claims 1 to 5, wherein two fixing flanges (18a, 18b) are integrated into the geometry of the mandrel so that the fixing flanges are integral with the respective ends of the core (12).

8. Method according to any preceding claim, wherein inserts or other fixing elements are assembled on the mandrel (30) and then encapsulated in the metal layer (25) when the latter is electroformed onto the outer shell of the mandrel (30) to form the core (12) of the device (10).

9. Flexible waveguide device (10), of the bellows type, for guiding a radio frequency signal at a given frequency range, the device (10) comprising: a core (12) comprising outer and inner side walls (14a, 14b), the inner walls (14b) delimiting a waveguide channel (16), two fixing flanges (18a, 18b) connected to or integral with respective ends of the core (12), and at least one flexible corrugated portion (20) formed on a part of the outer side walls (14a) of the core (12) and comprising a plurality of circumferential ribs (22) adjacent to each other, characterized in that each rib (22) is devoid of corrugation along its circumference.

10. Device (10) according to the preceding claim, characterized in that the flexible corrugated portion (20) may or may not be centered with respect to the two fixing flanges (18a, 18b).

11. Device (10) according to the preceding claim, characterized in that the distance between each adjacent rib (22) may vary between 0.1 and 5.0 mm and preferably between 0.5 and 2.0 mm as the device moves from a compressed configuration to an expanded configuration.

12. Device (10) according to any of claims 9 to 11, characterized in that a plurality of distinct flexible corrugated portions are formed on respective parts of the outer side walls (14b) of the core (12).

13. Device (10) according to the preceding claim, characterized in that three flexible corrugated portions are formed on the outer sidewall part (14a) of the core (12), two of the three flexible corrugated portions being respectively adjacent to the first and second fixing flanges (18a, 18b) while one of the three flexible corrugated portions is centered or not with respect to said fixing flanges (18a, 18b).

14. Device (10) according to any of claims 9 to 13, characterized in that the cross-section of the core (12) along the channel (16) is circular, elliptical, oval, hexagonal, square or rectangular.

15. Device (10) according to any of claims 9 to 14, characterized in that the cross-section of the core (12) is non-constant along the channel (16).

16. Device (10) according to any of claims 9 to 15, characterized in that the two fixing flanges (18a, 18b) comprise each a reinforcement in order to increase the rigidity of the flanges.

17. Device (10) according to any of claims 9 to 16, characterized in that the outer side walls (14a) of the core (12) are an electroformed part and in that inserts or other fixing elements are encapsulated in the electroformed part.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] Examples of embodiments of the invention are shown in the description illustrated by the attached figures in which.

[0042] FIG. 1 shows a perspective view of a flex waveguide device, of the bellows type, in a folded configuration, according to an embodiment of the invention,

[0043] FIG. 2 shows a side view of the waveguide device of FIG. 1 in a second position in which the device is arranged along a longitudinal axis when the bellows is in an extended configuration,

[0044] FIG. 3 shows a view similar to FIG. 2 when the bellows is in a compressed configuration,

[0045] FIG. 4 shows a view similar to FIG. 2 when the bellows is in a folded configuration,

[0046] FIG. 5 shows a side view of a mandrel used to manufacture the flexible waveguide device according to FIGS. 1 to 4,

[0047] FIG. 6 shows an axial section of a mandrel with a metal layer formed by electrodeposition,

[0048] FIG. 7 shows a view similar to FIG. 6 after the mandrel has been dissolved away with two flanges to be fixed to both ends of the flexible waveguide device,

[0049] FIG. 8 shows a perspective view of a waveguide in another embodiment when the bellows is in an unfolded configuration, and

[0050] FIG. 9 shows the waveguide of FIG. 8 in a folded configuration.

EXAMPLE(S) OF EMBODIMENTS OF THE INVENTION

[0051] The flexible waveguide device 10, of the bellows type, illustrated in FIGS. 1 to 4 comprises a core 12 having outer side walls 14a and inner side walls 14b (FIG. 6). The inner walls 14b define a waveguide channel 16.

[0052] Two fixing flanges 18a, 18b are connected to respective ends of the core 12. One or both of the fixing flanges 18a, 18b may include a reinforcement (not shown) so as to increase the rigidity thereof.

[0053] A flexible corrugated portion 20, of the bellows type, is formed on the outer side walls 14a of the core 12

[0054] The flexible portion 20 of the waveguide device 10 is centered with respect to the two fixing flanges 18a, 18b and comprises a plurality of adjacent ribs 22. These ribs 22 extend along the perimeter of the core 12 in a substantially rectangular trajectory. However, the trajectory of the ribs may vary depending on the geometry of the core 12.

[0055] For example, the ribs 22 may follow a circular trajectory. The distance between each adjacent rib may vary between 0.1 and 5.0 mm and preferably between 0.5 and 2.0 mm as the device moves from a compressed configuration to an extended configuration.

[0056] The waveguide device 10, illustrated in particular in FIG. 1, is made from a mandrel 30, illustrated in FIG. 5, which defines the outer shell of the device 10. The mandrel 30 is made by additive manufacturing.

[0057] In the present application, the term additive manufacturing refers to any method of manufacturing the mandrel 30 by adding material, according to computer data stored on the computer medium and defining the geometric shape of the mandrel.

[0058] In addition to stereolithography, the term also refers to other manufacturing methods such as liquid or powder curing or coagulation, including but not limited to binder jetting, DED (Direct Energy Deposition), EBFF (Electron Beam Freedom fabrication), FDM (Fused Deposition Modeling) PFF (Plastic Free Forming), aerosol, BPM (Ballistic Particle Manufacturing), SLM (Selective Laser Melting), SLS (Selective Laser Sintering), ALM (Additive Layer Manufacturing), polyjet, EBM (Electron Beam Melting), photopolymerisation, etc.

[0059] The mandrel 30 is preferably manufactured so as to obtain a hollowed mandrel with a minimum wall thickness determined so that the mandrel 30 has sufficient mechanical strength for the electrodeposition step while having the advantage of being able to be dissolved rapidly, the minimum time for dissolving the mandrel being of the order of 4 hours.

[0060] The mandrel 30 obtained by additive manufacturing is subjected to a surface treatment to make it suitable for the deposition of a metal layer 25 by electrodeposition (FIG. 6).

[0061] Copper or copper alloys, such as copper-tin, copper-zinc, or silver or silver alloy with a thickness varying between 0.05 mm and 5 mm is deposited on the surface of the mandrel by electrodeposition. Uniformity of thickness over the entire layer of deposited metal is very important to obtain a flexible waveguide with good mechanical properties.

[0062] Once the metal layer is deposited on the outer shell of the mandrel 30 by electroforming to form the core 12 of the device 10, the mandrel 30 and the metal layer 25 formed on the outer shell of the mandrel are immersed in a solvent bath.

[0063] The dissolving bath may be a succession of acidic or basic baths with immersion times ranging from 1 hour to 48 hours.

[0064] In an embodiment, during manufacturing of the flexible waveguide device 10, the two fixing flanges 18a, 18b are fixed to the respective ends of the core 12, for example by brazing. In an alternative embodiment, the two fixing flanges 18a, 18b are integrated into the geometry of the mandrel so that the fixing flanges are integral with the respective ends of the core 12.

[0065] Inserts or other (non-illustrated) fixing elements may be assembled onto the mandrel 30 and then encapsulated in the metal layer when the latter is electroformed onto the outer shell of the mandrel 30 to form the core 12 of the device 10.

[0066] The waveguide device 10 may comprise a plurality of separate flexible corrugated portions formed on respective parts of the outer side walls of the core.

[0067] For example, the waveguide device 10 may comprise three flexible corrugated portions that are formed on the outer sidewall portion 14a of the core 12. Two of the three flexible corrugated portions are respectively adjacent to the first and second fixing flanges 18a, 18b while one of the three flexible corrugated portions is centered or not with respect to the two fixing flanges 18a, 18b.

[0068] The cross-section of the core 12 along the channel 16 of the waveguide device may for example be circular, elliptical, oval, hexagonal, square or rectangular.

[0069] FIGS. 7 and 8 illustrate a waveguide device 10 of rectangular cross-section according to another embodiment in an unfolded and folded configuration respectively. In this embodiment, the device 10 comprises a flexible corrugated portion 20 having a plurality of adjacent circumferential ribs 22. Each adjacent rib 22 does not have a corrugation along its circumference. When the waveguide device 10 is in an unfolded configuration, the circumferential ribs 22 each lie in a plane orthogonal to the central axis of the channel of the waveguide device 10.

[0070] The waveguide device obtained by this manufacturing method has a high mechanical bending strength and thus facilitates its assembly.