Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
  • H01P1/161—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion sustaining two independent orthogonal modes, e.g. orthomode transducer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/12—Coupling devices having more than two ports

Definitions

• the present invention relates to a linearly polarized orthomode transducer which is both compact and dual-band.
• Orthomode transducers are passive components widely used in radio frequency antennas to enable their operation in both reception and transmission.
• TOMs such as side-arm TOMs, which are compact but not wideband.
• a side arm can be extended to operate in a second frequency band, however this extension is only possible for one of the two polarizations.
• TOMs such as "Boifot” junctions or "Turnstile” junctions, which are wideband, but which are not compact since they have an aperture greater than the wavelength X of a wave having the highest operating frequency of the TOM.
• Document EP2330681 A1 describes a single-band orthomode transducer comprising a septum polarizer whose septum allows a phase shift of 180° so as to produce a 45° polarization.
• Document EP2047564B1 describes an orthomode transducer comprising a coupling portion in the form of a side arm coupled to the transducer via a slot, allowing a 90° rotation of the side waveguide.
• the side arm increases the footprint of the transducer.
• broadband performance is not demonstrated for this type of transducer.
• An object of the present invention is to provide an orthomode transducer free from the limitations of known orthomode transducers.
• Another aim of the invention is to propose a wideband orthomode transducer with reduced bulk.
• a linearly polarized, broadband orthomode transducer obtained by additive manufacturing comprising: a hybrid coupler comprising: a first waveguide comprising a first input port and a first single-polarized output port; and a second waveguide, comprising a second input port and a second single-polarized output port; and a coupling portion connecting the first waveguide to the second waveguide; the orthomode transducer further comprising: a septum polarizer comprising: a third single-polarized input port connected to the first output port; and a fourth single-polarized input port connected to the second output port; and a third single-polarized output port; wherein the first and second waveguides are arranged symmetrically with respect to a plane of symmetry containing a septum of the septum polarizer.
• the symmetrical arrangement of the first and second waveguides of the coupler makes it possible to limit the footprint of the transducer, i.e. to obtain a compact cross-section over the entire length of the transducer. This results in a reduced size, for example allowing the densification of such devices in an antenna array.
• the coupling portion connects a first lateral face of the first waveguide and a second lateral face of the second waveguide, the first and second lateral faces being arranged in the same plane.
• the first side face may correspond to a face of the first waveguide of minimum dimension
• the second side face corresponds to a face of the second waveguide of minimum dimension
• this configuration makes it possible to further reduce the bulk by arranging the two waveguides of the coupler so that the largest lateral faces of these waveguides are opposite each other.
• the footprint of the coupler is reduced.
• the coupling portion comprises a prism with a trapezoidal base, a first portion of a rectangular face of the prism being in contact with the first lateral face of the first waveguide and a second portion of the rectangular face of the prism being in contact with the second lateral face of the second waveguide.
• This geometry of the coupling portion makes it easier to manufacture the additive coupler by limiting the overhanging portions.
• the coupling portion may include an impedance matching element.
• the coupling portion connects a first lateral face of the first waveguide and a second lateral face of the second waveguide, the first and second lateral faces being arranged in distinct and parallel planes.
• This arrangement advantageously makes it possible to limit the footprint of the transducer by placing the coupling portion between the two waveguides. Indeed, the external faces of the coupler, that is to say the faces of a waveguide not directly facing a face of the other waveguide, do not comprise a protruding element which would increase the footprint of the transducer.
• the coupling portion may comprise a plurality of branches, a first end of each branch being connected to the first waveguide and a second end of each branch being connected to the second waveguide.
• each branch forms a two-sided roof, a first side of the roof being adjacent to the first lateral face and a second side of the roof being adjacent to the second lateral face.
• a roof edge formed by the junction of the first and second sections may be contained in a plane perpendicular to a printing direction.
• the first pan may form an angle with the first lateral face of the first waveguide of between 35° and 55° and the second pan may form an angle with the second lateral face of the second waveguide of between 35° and 55°.
• each branch may form a double roof with two sides comprising a first roof with two sides, a first side of which is adjacent to the first lateral face and a second side of which is adjacent to the second lateral face, and comprising a second roof with two sides, a third side of which is adjacent to the first lateral face and a fourth side of which is adjacent to the second lateral face.
• the first side and the third side can advantageously form an angle with the first lateral face of between 35° and 55° and the second and the fourth side can form an angle with the second lateral face of between 35° and 55°.
• An edge of the first roof formed by the junction of the first and second panes may form an angle with a printing direction of between 35° and 55° and an edge of the second roof formed by the junction of the third pane and the fourth pane may form an angle with the printing direction of between 35° and 55°.
• Figure 1 schematically illustrates an orthomode transducer according to the invention.
• Figure 2 illustrates a septum polarizer
• Figure 3 illustrates a hybrid coupler comprising a trapezoidal coupling portion.
• Figures 4a and 4b illustrate an orthomode transducer incorporating the hybrid coupler of Figure 3.
• Figures 5a and 5b illustrate a hybrid coupler whose coupling portion comprises a plurality of branches suitable for additive manufacturing.
• Figures 6a and 6b illustrate a hybrid coupler whose coupling portion comprises a plurality of branches suitable for additive manufacturing.
• Figures 7a and 7b illustrate an orthomode transducer incorporating the hybrid coupler illustrated in Figures 6a and 6b.
• the orthomode transducer of the present invention comprises a hybrid coupler 1 connected to a septum polarizer 2.
• the hybrid coupler 1 comprises two waveguides (10,11) arranged in parallel and connected together by a coupling portion 12.
• the septum polarizer 2 is connected to the output ports of the hybrid coupler 1 via two input ports.
• an electromagnetic wave is propagated from the hybrid coupler 1 to the septum polarizer 2, and when it operates in reception, from the septum polarizer to the hybrid coupler.
• the terminology used in the context of the present invention such as “input port” or “output port”, corresponds to a transmission mode of operation although the transducer can operate indifferently in transmission and/or in reception.
• the direction of propagation of the waves in the transducer is therefore parallel to the longitudinal direction of the waveguides of the coupler 1 and the polarizer 2.
• the orthomode transducer of the present invention is obtained by additive manufacturing.
• additive manufacturing describes any method of manufacturing parts by adding material, according to computer data stored on a computer medium and defining a model of the part.
• the expression also designates other manufacturing methods by hardening or coagulation of liquid or powder in particular, including without limitation methods based on ink jets (binder jetting), DED (Direct Energy Deposition), EBFF (Electron beam freeform fabrication), FDM (fused deposition modeling), PFF (plastic freeforming), by aerosols, BPM (ballistic particle manufacturing), powder bed, SLS (Selective Laser Sintering), ALM (additive Layer Manufacturing), polyjet, EBM (electron beam melting), photopolymerization, etc.
• the orthomode transducer comprises two elements whose functions differ, i.e. a hybrid coupler and a septum polarizer, its manufacture does not require any assembly after the 3D printing steps.
• the coupler and the polarizer are therefore typically made in one piece.
• Hybrid couplers are four-port directional couplers used to separate or combine waves with particular phase relationships. There are mainly two types of hybrid couplers, one producing a 90° phase shift between the two output ports and the other producing a 180° phase shift between the two output ports. Hybrid couplers also work as power dividers since typically the wave undergoes an attenuation of 3dB, i.e. the waves propagated by each of the output ports have a power equal to 50% of the power of the input wave.
• Figure 2 illustrates a prior art hybrid coupler of the Riblet type consisting of two waveguides coupled together through an opening in the adjoining walls of the two waveguides.
• the first waveguide 10 thus comprises a first input port 100 and a first output port 101
• the second waveguide comprises a second input port 110 and a second output port 111.
• the phase shift at the output ports depends on the coupling portion 12.
• Each of these four ports is single-polarized.
• the coupling portion 12 of the coupler 1 allows a wave propagating in the first waveguide 10 to pass, at least partially, into the second waveguide 11 and a wave propagating in the second waveguide 11 to pass, at least partially, into the first waveguide 10.
• a wave propagating through the first input port 100 of the first waveguide 10 will be distributed between the first and second waveguides (10, 11) via the coupling portion 12 and thus exit the hybrid coupler 1 through the first and second output ports (100, 101).
• the output ports (101,111) of the hybrid coupler are connected to the septum polarizer 2 via a third input port 200 and a fourth input port 210 of the polarizer, respectively.
• the other end of the polarizer 2 comprises a third output port 201.
• the third output port may be connected to a radiating element of the antenna, or even function as a radiating element itself in certain embodiments.
• Each of the third and fourth input ports (200,210) of the polarizer are single-polarized.
• the third output port 201 of the polarizer is dual-polarized.
• first and second waveguides (10, 11) as well as the septum polarizer 2 can also have a circular, elliptical, polygonal (regular or irregular), eg triangular, pentagonal, hexagonal, octagonal, etc. section.
• the hybrid coupler 1 is used to excite the third and fourth input ports of the polarizer 2 simultaneously so as to create two circular polarizations.
• the combination of these two circular polarizations by the septum of the polarizer results in a linear polarization in the third output port 201.
• the septum 22 of the polarizer 2 is arranged in a plane parallel to the direction of propagation of the waves in the transducer.
• the septum is typically of variable height, the highest portion of the septum being arranged at the end of the polarizer comprising the third and fourth input ports (200, 210).
• the height of the septum may typically decrease linearly or in steps.
• FIG. 2 illustrates a polarizer 2 comprising a septum 22 decreasing in steps.
• the orthomode transducer of the present invention can be implemented in different radio frequency devices for various frequency bands depending on their application.
• the present invention can be typically implemented in devices for the bands: X, Ku, Ka, QV, Ku/Ka, Ka/QV.
• the first and second waveguides (10, 11) of the hybrid coupler 1 are arranged symmetrically with respect to a plane of symmetry containing the septum 22 of the polarizer 2.
• the section of the septum polarizer 2 measured perpendicular to the direction of propagation of the waves in the orthomode transducer is the same as the section of the hybrid coupler 1 measured perpendicular to this same direction of propagation.
• the diameter of the orthomode transducer (or footprint of the transducer) measured in a plane perpendicular to the direction of propagation is essentially constant along the direction of propagation. This characteristic allows to increase the compactness of the transducer and therefore reduce its size, particularly with a view to use in a compact antenna network.
• the hybrid coupler 1 produces a phase shift of 90° or 180°.
• an electromagnetic wave propagating through the first or second input port (100, 110) of the hybrid coupler will be divided into two waves phase-shifted relative to each other by 90° or 180° between the first and second output ports (101, 111).
• Each of the two output waves is further attenuated by -3 dB relative to the input wave.
• the hybrid coupler receives two waves phase-shifted by 90° or 180° and combines them into a wave whose power is doubled, i.e. increased by 3 dB. Two main embodiments are described below, each corresponding to one of the two phase shifts.
• a hybrid coupler 1 according to a first embodiment is illustrated in FIG. 3.
• the first and second waveguides 10, 11 are connected by the coupling portion 12.
• this coupler divides a wave propagated by the first or second input port (100, 110) into two waves phase-shifted by 90° via the coupling portion 12.
• the two input ports of the septum polarizer 2 are thus each excited simultaneously by one of these two waves phase-shifted by 90°, thus creating two circular polarizations phase-shifted by 90°.
• the two circular polarizations are then combined in the septum polarizer 2, creating in the output port 201 of the septum polarizer, a linearly polarized wave inclined at 45° relative to the input wave of the hybrid coupler 1.
• the first and second waveguides (10, 11) of the hybrid coupler 1 may have a rectangular section and are arranged parallel to each other, as illustrated in FIG. 3.
• one of the long sides of the rectangular section of the first waveguide is parallel to one of the long sides of the rectangular section of the second waveguide, so that the largest walls rectangular sidewalls of the first and second waveguides are arranged in parallel planes.
• the two waveguides (10, 11) are connected to each other by a coupling portion 12. More precisely, this coupling portion 12 connects one of the small rectangular side walls of the first waveguide 10 with one of the small rectangular side walls of the second waveguide 11.
• the two small rectangular walls are arranged in the same plane, this plane being perpendicular to the larger rectangular side walls of each waveguide.
• Each of the smaller walls is provided with an opening at the coupling portion so as to allow a wave to pass from the first waveguide to the second or from the second to the first.
• the coupling portion comprises a waveguide portion extending between these two openings so as to propagate the wave between these two openings.
• the waveguide portion of the coupling portion 12 has a trapezoidal geometry. More precisely, this waveguide portion comprises a rectangular base contiguous to the smaller side walls of the first and second waveguides (10, 11). The waveguide portion extends in a direction perpendicular to the rectangular base and its section parallel to the base decreases until it forms a rectangular upper face opposite the base, this rectangular face thus having dimensions smaller than those of the base.
• the coupling portion 12 may be provided with one or more impedance matching elements such as grooves, internal protrusions or openings in a wall of the coupling portion. These elements aim to optimize the transmission of signals in the coupling portion. As illustrated in FIG. 3, an opening on the upper face of the coupling portion may be provided in order to improve the transmission of a signal between the first and second waveguides (10, 11).
• Figures 4a and 4b illustrate an orthomode transducer according to the first embodiment mentioned above.
• the hybrid coupler 1 and the septum polarizer 2 are made in one piece by additive manufacturing so that no assembly is necessary to obtain the transducer of the present invention.
• the printing direction of the layers for additive manufacturing coincides with the propagation direction of the waves in the orthomode transducer.
• certain portions of the transducer are adapted for additive manufacturing. In particular, certain cantilevered portions are inclined so as to form an angle significantly less than 90° with the printing direction.
• the coupling portion 12 of the hybrid coupler may comprise side faces forming an angle of between 35° and 55° with the direction of propagation so as to eliminate the need for any printing media.
• the orthomode transducer comprises a hybrid coupler 1 producing a phase shift of 180° between the two waves at the outputs of the coupler when the device operates in transmission.
• the coupling portion 12 of the hybrid coupler 1 connects a first lateral face of the first waveguide 10 and a second lateral face of the second waveguide 11, the first and second lateral faces being arranged in distinct and parallel planes.
• this hybrid coupler 1 divides a wave propagated by the first or second input port (100, 110) into two waves phase-shifted by 180° via the coupling portion 12.
• the two input ports of the septum polarizer 2 are thus each excited simultaneously by one of these two waves phase-shifted by 180°, thus creating two circular polarizations phase-shifted by 180°.
• the coupling portion 12 comprises a plurality of branches 121, each branch being connected on the one hand to the first lateral face of the first waveguide 10 and on the other hand to the second lateral face of the second waveguide 11.
• each branch 121 intersects the plane of symmetry of the first and second waveguides (10, 11).
• Each branch 121 comprises a waveguide for propagating a wave via an opening in the first waveguide 10 towards the second waveguide 11 via an opening in the wall of the second side face, or vice versa.
• each branch 121 comprises a waveguide extending perpendicular to the lateral faces of the first and second waveguides (10, 11).
• the section of this waveguide may be triangular, square, rectangular, pentagonal, hexagonal, or more generally polygonal.
• the section of this waveguide may also comprise curved portions in addition to or replacing rectilinear portions.
• certain portions of the hybrid coupler according to the second main embodiment are inclined relative to the printing direction.
• the printing direction is illustrated in FIGS. 5a and 5b by the z axis and corresponds to the direction of propagation of a signal in the coupler.
• branches 121 may comprise inclined portions so as to limit the cantilever sections and thus facilitate, or even make possible, the additive manufacturing of the device.
• each branch 121 advantageously forms a two-sided roof, each of the sides being adjacent to one or the other of the first and second waveguides (10, 11).
• the edge of the roof formed by the junction of the two sides is typically contained in a plane perpendicular to the printing direction z.
• the inclination of the two sides may be such that the edge of the roof points towards the septum polarizer 2 or towards the first and second input ports (100, 110).
• the two-sided roof has a V-shaped profile pointing in one direction or the other along the printing axis z.
• Such a geometry of the branches 121 advantageously makes it possible to reduce the overhanging portions and therefore to facilitate their additive manufacturing, in particular by eliminating the need for printing support.
• each panel forms an angle with the lateral face of the waveguide to which it is adjacent of between 35° and 55°, preferably between 40° and 50°.
• the branches 121 are symmetrical with respect to the plane of symmetry of the first and second waveguides (10, 11). In other words, each pan is symmetrical to the other with respect to the plane of symmetry of the first and second waveguides.
• each branch 121 advantageously forms a double roof with two sides. More precisely, each branch 121 comprises a first roof with two sides, each of the sides of which is adjacent to the first or second waveguide (10, 11) and a second roof with two sides, each of the sides of which is adjacent to the first or second waveguide (10, 11).
• the first and second roof with two sides are connected to each other such that the edge of the first roof and the edge of the second roof are contained in the same plane.
• the edge of the first roof forms an angle with the edge of the second roof at the location of the connection between the two roofs.
• FIGS. 6a and 6b is similar to that illustrated in FIGS. 5a and 5b, except that each branch of the coupling portion forms a bend in the plane containing the edges of the branches.
• each branch 121 has a double symmetry. Indeed, each branch has a first symmetry with respect to the plane of symmetry of the first and second waveguides (10, 11) and a second symmetry with respect to the plane perpendicular to the plane of symmetry of the first and second waveguides containing the printing direction z.
• the orthomode transducer including the branch coupler has overall symmetry along a plane containing the septum 22.
• Reference numbers used in the figures are used in the figures.

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• Waveguide Switches, Polarizers, And Phase Shifters (AREA)
• Optical Integrated Circuits (AREA)

Applications Claiming Priority (2)

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ID=87554507

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Family Cites Families (4)

• 2023
  • 2023-03-10 FR FR2302229A patent/FR3146549B1/fr active Active
• 2024
  • 2024-03-07 KR KR1020257033158A patent/KR20250160981A/ko active Pending
  • 2024-03-07 IL IL322804A patent/IL322804A/en unknown
  • 2024-03-07 EP EP24712298.9A patent/EP4677690A1/de active Pending
  • 2024-03-07 CN CN202480014664.5A patent/CN120770093A/zh active Pending
  • 2024-03-07 WO PCT/IB2024/052216 patent/WO2024189480A1/fr not_active Ceased

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