6-port orthogonal mode junction

Abstract

A six-port orthogonal mode transducer suitable for additive manufacturing and capable of distinguishing between two frequency bands is provided. The present invention relates to a six-port orthomode transducer (1) manufactured by additive manufacturing, the transducer (1) comprising: a dual-polarized input port (10) and a dual-polarized output port (11), the input port and the output port defining a main direction (100) corresponding to the direction of propagation of a signal between the input port (10) and the output port (11); a first single polarization side port (12) extending along a first axis (120) intersecting the main direction (100); a second single-polarization side port (13) extending along a second axis (line 130) intersecting the main direction (100) and facing the first side port (12); a third single polarization side port (14) extending along a third axis (140) intersecting the main direction (100); a fourth single-polarization side port (15) extending along a fourth axis (150) intersecting the main direction (100) and facing the third side port (14); The transducer (1) has its first, second, third and fourth intersecting axes each forming an angle between 15° and 75° with respect to the main direction (100), characterized by a high-pass filter arranged between the side port and the output port and comprising at least two filtering slots (21). The invention also relates to such an orthogonal mode transducer and a transmit / receive antenna comprising a plurality of low-pass filters.

Description

[Technical Field]

[0001] The present invention relates to a six-port orthomode transducer suitable for additive manufacturing. [Background technology]

[0002] In the field of radio frequency transmission, a dual-polarized antenna is an antenna that can emit and receive electromagnetic waves according to two orthogonal polarizations. These antennas generally consist of a radiating element (usually horn-shaped) and a feed chain. This feed chain must be able to distinguish between the two orthogonal polarizations, combining the two signals when transmitting and separating them when receiving. This distinction can be achieved by a dual-polarized orthogonal mode transformer (OMT), such as a "rotary" junction with an input port connected to the horn and two pairs of side ports arranged opposite each other. Each pair allows the separation of one of the polarizations.

[0003] If such antennas are additionally dual-band, i.e. capable of operating in two frequency bands, the supply chain must also be able to distinguish between the two frequency bands, which is usually done by bandpass filters placed in the supply chain.

[0004] Although the operations of polarization coupling and decoupling and frequency filtering are entirely different, certain orthogonal mode converters known in the prior art allow for combined polarization and frequency discrimination in a single device. Such devices typically have a total of six ports, including an input port and an output port (usually dual-polarized and arranged coaxially), and four side ports (usually single-polarized). Polarization discrimination is performed at the side ports, and frequency band discrimination can be performed, for example, using a high-pass filter connected to the output port and a low-pass filter connected to the side ports.

[0005] However, with the recent rapid growth of additive manufacturing in the field of radio frequency transmission, there is an increasing need to improve the design of such antennas so that they can be manufactured by additive manufacturing. In particular, cross-polarized antennas, and orthomode transducers in general, have relatively large cantilevered sections, such as parts of lateral waveguides or bandpass filters, which make efficient and inexpensive additive manufacturing impossible. This is because the overhanging sections need to be supported during manufacturing, and then the supports must be removed manually, which is both time-consuming and expensive.

[0006] Patent Document 1 describes a six-port orthogonal mode converter that can distinguish two orthogonally polarized waves propagating in a main waveguide using two pairs of rectangular cross-section side ports. The four side ports extend radially relative to the main propagation direction of the signal in the main waveguide, i.e., perpendicular to this main propagation direction. A low-pass filter is connected to the port of the orthogonal mode converter that is parallel to the main propagation direction, and four high-pass filters are connected to the four side ports. As mentioned above, in this device, the four side ports and low-pass filters are not suitable for additive manufacturing.

[0007] Non-Patent Document 1 describes a six-port orthogonal mode transducer suitable for additive manufacturing. Frequency discrimination is achieved by a virtual filter constructed by gradually narrowing the inner diameter of the main waveguide, and also by a low-pass filter connected to the side ports. The side ports are oriented so that the input port, i.e., the port to be connected to the horn antenna, and the port with the H-plane divider form two pairs of side ports. In other words, the longest side of the side port opening is aligned with the propagation direction. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2013 / 0342282 [Non-patent literature]

[0009] [Non-Patent Document 1] G. Addamo et al., “3D Printing of a Monolithic K / Ka-Band Dual-Circular Polarization Antenna-Feeding Network,” IEEE Access, vol. 9, pp. 88243-88255, 2021, DOI:10.1109 / ACCESS.2021.3089826 Summary of the Invention [Problem to be solved by the invention]

[0010] One of the objects of the present invention is to provide a six-port orthomode transducer that is not limited by those known in the prior art.

[0011] It is another object of the present invention to provide a six-port orthomode transducer that is suitable for additive manufacturing.

[0012] Another object of the present invention is to propose a six-port orthogonal mode transducer that can distinguish between two frequency bands. [Means for solving the problem]

[0013] According to the invention, these objects are achieved in particular by a six-port orthomode transducer manufactured by additive manufacturing, the six-port orthomode transducer comprising: a dual-polarized input port; and a dual-polarized output port, the input port and the output port defining a main direction corresponding to a direction of propagation of a signal between the input port and the output port; a first single polarization side port extending along a first axis that intersects the primary direction; a second single polarization side port opposite the first side port, the second single polarization side port extending along a second axis that intersects the primary direction; a third single polarization side port extending along a third axis that intersects the primary direction; a fourth single polarization side port opposite the third side port, the fourth single polarization side port extending along a fourth axis that intersects the main direction; Equipped with In the six-port orthogonal mode transducer, each of the first intersecting axis, the second intersecting axis, the third intersecting axis, and the fourth intersecting axis forms an angle between 15° and 75° with respect to the main direction; The high-pass filter is disposed between a plurality of side ports and the output port and includes at least two filtering slots.

[0014] The orthomode transducer may be characterized in that the high-pass filter comprises a platform extending radially from the main direction, and the at least two filtering slots may be provided in the platform.

[0015] The platform may include at least one support arch extending radially from the main direction.

[0016] To allow for additive manufacturing of the transducer, the at least one support arch may comprise at least one cantilevered surface that forms an angle of between 15° and 75° with respect to the main direction.

[0017] The orthomode transducer may have the shorter dimension of each of the four side ports parallel to the major direction.

[0018] The output port may include at least one ridge on an inner wall thereof.

[0019] The platform may include a protruding impedance matching element extending in the main direction.

[0020] The diameter of the input port may be greater than the diameter of the output port.

[0021] The orthomode transducer may be characterized by a double symmetry along two mutually orthogonal planes, said two orthogonal planes comprising said main directions.

[0022] The above-mentioned objects are also achieved by an antenna for transmitting and / or receiving dual polarized signals, comprising an orthogonal mode converter as described above, the antenna comprising four low pass filters, each side port connected to one of the four low pass filters.

[0023] Each of the four low pass filters may include at least one knurled inner surface.

[0024] The antenna may be characterized by a double symmetry along two mutually orthogonal planes, said two orthogonal planes comprising said main direction.

[0025] Several embodiments of the present invention are set forth in the following description, which are illustrated by the accompanying drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 shows a three-quarter perspective view (a view seen from the front and at an angle) of a six-port orthogonal mode transducer. [Figure 2] FIG. 2 shows a longitudinal cross section of a six-port orthomode transducer. [Figure 3] FIG. 3 shows a longitudinal cross section of a six-port orthomode transducer. [Figure 4] FIG. 4 shows a top view of a six-port orthomode transducer including a filtering platform. [Figure 5a] FIG. 5a shows a filtering platform suitable for additive manufacturing. [Figure 5b] FIG. 5b shows a top view of a filtering platform suitable for additive manufacturing. [Figure 6] FIG. 6 shows a longitudinal cross section of a filtering platform suitable for additive manufacturing. [Figure 7] FIG. 7 shows a cross-sectional side view of a dual-polarization diplexer with a six-port orthogonal mode transformer and a side filter with a notch on one side. [Figure 8] FIG. 8 shows a side cross section of a dual-polarization diplexer with a six-port orthogonal mode transformer and side filters notched on both sides. DETAILED DESCRIPTION OF THE INVENTION

[0027] 1 shows an orthomode transducer 1 according to the present invention, comprising an input port 10 and an output port 11. A main direction 100 is defined, which corresponds to the direction of propagation of the signal between the input and output ports. Four side ports (12, 13, 14, 15) are connected to the orthomode transducer along four axes intersecting the main direction.

[0028] In this specification, the orthogonal mode converter of the present invention is defined such that the main direction of propagation between the input port 10 and the output port corresponds to the z-direction, which coincides with the 3D printing direction. The x- and y-directions lie in a plane orthogonal to the z-direction and correspond to the orthogonal directions of each polarization.

[0029] The input port 10 may be a standard waveguide with a circular or rectangular cross section to receive and transmit signals with circular, elliptical, or linear polarization. In general, the cross section of the input port may be any geometric shape deemed appropriate by those skilled in the art, including, for example, a pentagonal, hexagonal, or polygonal cross section with more than six sides, or a combination of polygonal cross sections with curved sides. For use in a dual-polarized antenna, the input port 10 is typically connected to a waveguide or directly to an emitting element such as a horn. The output port 11 has a portion coaxial with the input port 10 and is dual-polarized. Similarly, the output port 11 may be a waveguide with any geometric shape deemed appropriate by those skilled in the art, including, for example, a pentagonal, hexagonal, polygonal section with more than six sides, or a combination of polygonal sections with curved sides.

[0030] Between the input 10 port and the output 11 port, a first side port 12 is provided, extending along a first axis 120 intersecting the main direction 100, facing a second side port 13 extending along a second axis 130 intersecting the main direction 100. The first and second ports allow signals to be separated or combined according to a first polarization P1. The third side port 14 extends along a third axis 140 intersecting the main direction 100, facing a fourth side port 15 extending along a fourth axis 150 intersecting the main direction 100. The third and fourth ports allow signals to be separated or combined according to a second polarization P2. Each of the four side ports is thus single polarized.

[0031] 1, the side ports (12, 13, 14, 15) are rectangular in cross section, with the smallest side of the rectangular cross section aligned with the main direction 100. This results in the combination of input port 10 and a pair of opposing side ports (i.e., corresponding to the same polarization) forming an E-plane divider or combiner. The electric field directions of waves propagating through two side ports corresponding to the same polarization are therefore opposite.

[0032] As shown in FIG. 3 , the first, second, third, and fourth axes (120, 130, 140, 150) each form an angle of 15° to 75°, preferably 35° to 55°, with the main direction 100. This tilt with respect to the z-direction enables additive manufacturing of the side ports. Indeed, because the z-axis generally coincides with the 3D printing direction, tilting the side ports with respect to this direction reduces the physical constraints imposed by gravitational forces on the side ports, thereby reducing or even eliminating the need for supports during manufacturing. The tilt of the side ports limits the external volume of the orthomode transducer, thereby enabling its miniaturization.

[0033] In one embodiment shown in FIG. 4, the arrangement of the side ports (12, 13, 14, 15) and the input 10 and output 11 ports allows the entire orthogonal mode converter 1 according to the present invention to be arranged along two mutually orthogonal planes: One of these two planes of symmetry comprises a first axis and a second axis (120, 130) and a main direction 100; The other plane of symmetry comprises the third and fourth axes (140, 150) and the main direction 100. It has become something.

[0034] The orthogonal mode converter 1 according to the present invention comprises a high-pass filter disposed between the side port and the output port 11. The high-pass filter comprises at least two filtering slots 21 for removing long waves so that only short waves can pass through the output port 11.

[0035] In the context of the present invention, the terms "high frequency" ("short wave") and "low frequency" ("long wave") may correspond to different ranges of values depending on the embodiment. Indeed, the present invention can be implemented in different devices covering various frequency bands depending on the application. For example, the present invention can typically be used in devices covering at least one or all of the X, Ku, Ka, QV, Ku / ka, and Ka / QV bands.

[0036] In the X-band, longwave is typically between 7.25 GHz and 7.75 GHz, and shortwave is between 7.9 GHz and 8.4 GHz.

[0037] In the Ku band, long wave typically extends from 10.7 GHz to 12.75 GHz and short wave from 13.25 GHz to 4.5 GHz, or a subrange (segment) of these particular bands.

[0038] In the Ka band, long wave typically ranges from 17.3 GHz to 21.2 GHz, and short wave ranges from 27 GHz to 31 GHz, or any subrange of these particular bands.

[0039] In the QV band, long wave typically ranges between 37.5 GHz and 42.5 GHz, and short wave ranges between 42.5 GHz and 52.5 GHz, or any subrange of these particular bands.

[0040] In the Ku / Ka bands, long wave typically comprises between 10.7 GHz and 12.75 GHz, and short wave between 13.25 GHz and 21 GHz, or subranges of these particular bands, respectively. Alternatively or complementary, long wave typically comprises from 13.25 GHz to 21.2 GHz, short wave from 13.25 GHz to 21.2 GHz, and very short wave from 27 GHz to 31 GHz, or subranges of these particular bands.

[0041] In the Ka / QV bands, long wave typically comprises 27 GHz to 42.5 GHz and short wave from 42.5 GHz to 52.5 GHz, or subranges of these particular bands.

[0042] In one embodiment, the output port 11 has a cross-section with a diameter smaller than the cross-section of the input port 10. This causes part of the frequency band of the input port to correspond to a range below the cutoff frequency of the output port. This reduced diameter therefore allows for the addition of "virtual" filtering in addition to the high-pass filter.

[0043] For long waves, they are propagated through side ports (12, 13, 14, 15), which themselves can be connected to low-pass filters for high frequency rejection.

[0044] In a preferred embodiment, the high-pass filter comprises a platform 20 provided with filtering slots 21. The platform 20 extends radially around the main direction 100. This platform is shown in Figure 3 and includes an upper surface facing the input port 10 and a lower surface facing the output port 11. Preferably, the upper surface of the platform is perpendicular to the main direction 100.

[0045] The filtering slots 21 may be defined on the one hand by the platform 20 and on the other hand by the inner wall of the output port 11. Alternatively or complementary, the filtering slots 21 may be defined entirely by the platform 20, in the sense that the sides of each slot are defined by part of the platform.

[0046] 4, four triangular filtering slots 21 are formed by the platform 20 and the interior wall 110 of the output port 11. The platform comprises four arms extending from the main direction 100 towards the interior wall 110 of the output port 11.

[0047] The platform 20 may include at least one support arch 22 to enhance stability of the platform during additive manufacturing and / or during use of the orthomode transducer. As shown in Figure 5a, the platform 20 may include multiple support arches 22 that converge at the center of the platform in the primary direction.

[0048] To facilitate additive manufacturing of the platform 20 and the support arch 22, the cantilevered surfaces 220 of the support arches relative to the z-direction advantageously form an angle REF with the axis (z) between 15° and 75°, preferably between 35° and 55°. Figure 6 shows a cross-section of the platform, with two support arches 220 forming an angle β with the main direction 100. As with the side ports, from an additive manufacturing perspective, the optimal inclination is approximately 45°. However, for reasons related to, for example, the internal geometry of the orthomode transducer, cantilevered surfaces with an inclination in the range of 15° to 75° are also possible.

[0049] In one embodiment, ridges 23 parallel to the main direction may be provided on the inner surface of the output port 11. These ridges may, for example, allow for widening the frequency band and / or matching the impedance of the output port 11. As shown in Figure 4, the coupling slots of the high-pass filter may divide the output port 11 into multiple waveguides, the inner walls of which may be provided with ridges 23. The platform 20 may, for example, divide the output port 11 into four triangular waveguide sections, each with a side corresponding to a side defined by the inner wall 110 of the output port and provided with a ridge 23 on that side.

[0050] The platform 20 may include a protruding impedance matching element 24. As shown in Figure 5a, the protruding element may extend from the platform 20 in a main direction 100, allowing the platform to act as a support for the protruding element during additive manufacturing.

[0051] The orthomode converter 1 is typically used in the supply chain of a radio frequency antenna, which further comprises an antenna horn connected to the input port 11. Such antennas also usually include a low pass filter 30 connected to the side ports (12, 13, 14, 15).

[0052] 7 shows an embodiment in cross section, in which each side port is connected to a low-pass filter 30, e.g., a sawtooth low-pass filter on the side wall. Each low-pass filter extends along the main direction 100. These filters are advantageously symmetrical along the two planes of symmetry mentioned above, i.e., along the plane comprising the main direction 100 and the first and second intersecting axes (120, 130), as well as along the plane comprising the main direction 100 and the third and fourth intersecting axes (140, 150). In this way, the orthogonal mode transducer and low-pass filter assembly maintains double-plane symmetry.

[0053] 8 shows an embodiment in which the low-pass filters 30 connected to the side ports have two sawtooth internal walls, also extending along the main direction 100. Again, double symmetry of the orthogonal-mode transducer and low-pass filter assembly can be achieved.

[0054] In a supply chain comprising the above-mentioned low-pass filters and the orthogonal mode converter according to the invention, the two pairs of low-pass filters corresponding to the first and second polarizations can then be recombined using two single-band combiners. In such a supply chain, the output ports may be connected to single-band orthogonal mode converters. Advantageously, the single-band combiners and the single-band orthogonal mode converters are also arranged to maintain the two-way symmetry of the supply chain. [Explanation of symbols]

[0055] 1 Orthogonal mode transducer 10 input ports 100 main direction 11 output ports 110 Inner wall of output port 12 First side port 13 Second side port 14 Third side port 15 4th side port 120 First Intersecting Axis 130 Second Intersecting Axis 140 Third Intersecting Axis 150 Fourth Intersecting Axis 20 Platform 21 Filter groove 22 Support Arch 220 Cantilevered 23 Ridge 24 Protruding impedance matching element 30 Low-pass filter

Claims

1. A six-port orthomode transducer (1) manufactured by additive manufacturing, comprising: a dual-polarized input port (10); and a dual-polarized output port (11), said input port and said output port defining a main direction (100) corresponding to the direction of propagation of a signal between said input port (10) and said output port (11), a first single-polarization side port (12) extending along a first axis (120) intersecting the main direction (100); a second single-polarization side port (13) facing the first side port (12), the second single-polarization side port (13) extending along a second axis (130) intersecting the main direction (100); a third single-polarization side port (14) extending along a third axis (140) intersecting the main direction (100); a fourth single-polarized side port (15) facing the third side port (14), the fourth single-polarized side port (15) extending along a fourth axis (150) intersecting the main direction (100); In the six-port orthogonal mode transducer (1), each of the first intersecting axis, the second intersecting axis, the third intersecting axis, and the fourth intersecting axis forms an angle between 15° and 75° with respect to the main direction (100), A six-port orthogonal mode transducer (1) characterized by a high-pass filter arranged between the plurality of side ports and the output port and comprising at least two filtering slots (21).

2. 2. The orthogonal mode converter (1) of claim 1, characterized in that the high-pass filter comprises a platform (20) extending radially from the main direction (100), and the at least two filtering slots (21) are provided in the platform.

3. The orthomode transducer (1) of claim 2, wherein the platform (20) comprises at least one support arch (22) extending radially from the main direction (100).

4. 4. The orthogonal mode converter (1) according to claim 3, wherein the at least one support arch (22) comprises at least one cantilever beam (220) that forms an angle (β) between 15° and 75° with respect to the main direction (100).

5. An orthogonal mode converter (1) according to any one of claims 1 to 4, characterized in that the shorter dimension of each of the four side ports (12, 13, 14, 15) is parallel to the main direction (100).

6. 6. The orthogonal mode converter (1) according to any one of claims 1 to 5, wherein the output port (11) comprises at least one ridge (23) provided on an inner wall (110) of the output port (11).

7. An orthogonal mode transducer (1) according to any one of claims 2 to 5 and claim 6 relying on claim 2, wherein the platform (20) comprises a protruding impedance matching element (24).

8. The orthomode transducer (1) according to any one of claims 1 to 7, wherein the diameter of the input port (10) is greater than the diameter of the output port (11).

9. 9. An orthogonal mode converter (1) according to any one of claims 1 to 8, characterized by a double symmetry along two mutually orthogonal planes, said two orthogonal planes comprising said main direction (100).

10. An antenna for transmitting and / or receiving dual polarized signals, comprising an orthogonal mode converter (1) according to any one of claims 1 to 9, The antenna comprises four low-pass filters (30), each side port (12, 13, 14, 15) being connected to one of the four low-pass filters (30).

11. 11. The antenna of claim 10, wherein each of the four low pass filters (30) comprises at least one inner surface having a plurality of knurls.

12. 12. Antenna according to claim 10 or 11, characterized by a double symmetry along two mutually orthogonal planes, said two orthogonal planes comprising said main direction (100).

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