WO2022053160A1 - Appareil d'alimentation en deux ondes radio dans un réflecteur décalé - Google Patents

Appareil d'alimentation en deux ondes radio dans un réflecteur décalé Download PDF

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Publication number
WO2022053160A1
WO2022053160A1 PCT/EP2020/075625 EP2020075625W WO2022053160A1 WO 2022053160 A1 WO2022053160 A1 WO 2022053160A1 EP 2020075625 W EP2020075625 W EP 2020075625W WO 2022053160 A1 WO2022053160 A1 WO 2022053160A1
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WO
WIPO (PCT)
Prior art keywords
mirror
feeder
radio wave
band
dielectric
Prior art date
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PCT/EP2020/075625
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English (en)
Inventor
Roberto Giusto
Original Assignee
Huawei Technologies Co., Ltd.
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Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Priority to PCT/EP2020/075625 priority Critical patent/WO2022053160A1/fr
Publication of WO2022053160A1 publication Critical patent/WO2022053160A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/18—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces
    • H01Q19/19—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface
    • H01Q19/191—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface wherein the primary active element uses one or more deflecting surfaces, e.g. beam waveguide feeds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
    • H01Q15/0033—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective used for beam splitting or combining, e.g. acting as a quasi-optical multiplexer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/12—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems
    • H01Q3/16—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device
    • H01Q3/20—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device wherein the primary active element is fixed and the reflecting device is movable
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
    • H01Q5/45—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements using two or more feeds in association with a common reflecting, diffracting or refracting device

Definitions

  • the present invention relates to the field of wireless communications. More specifically, the invention relates to an apparatus for feeding two radio waves into an offset reflector of an antenna, and to an antenna comprising such an apparatus.
  • Dual-band microwave/millimeter-wave dish antennas have been used for microwave backhaul applications. Usually such antennas operate in compliance with certain technical standards, such as the European ETSI Standard EN30221704, wherein Class 3 applies to the microwave band portion and Class 2 to the millimeter-wave band portion of such dual band antennas. It is desirable to have dual-band microwave/millimeter-wave dish antennas with low side-lobe levels. This would allow, for instance, in the framework of Terrestrial Wireless Networks, to operate a large number of dual-band microwave/millimeter-wave dish antennas in dense regions making frequency reuse.
  • a first aspect relates to an apparatus for feeding a first and a second radio wave to an offset reflector (108).
  • the first radio wave and the second radio wave are in a first radio frequency, RF, band and in a second RF band, respectively, the second RF band being above the first RF band.
  • the feed apparatus comprises a first feeder (101), a second feeder (102), a first mirror (105), a second mirror (106) and a dichroic filter (107).
  • the first feeder (101) is configured to emit the first radio wave (e.g. from its phase center) toward the offset reflector (108).
  • the second feeder (102) is configured to emit the second radio wave (e.g. from its phase center) toward the first mirror (105).
  • the first mirror (105) is configured to reflect the second radio wave toward the second mirror (106).
  • the second mirror (106) is configured to reflect the second radio wave toward the dichroic filter (107).
  • the dichroic filter (107) is configured to pass the first radio wave and to reflect the second radio wave toward the offset reflector (108).
  • the feed apparatus allows to control and minimize the sidelobe levels of a dual-band antenna using low-cost components and, at the same time, can provide an antenna beam steering mechanism which is performant, rugged, simple, low-cost and reliable.
  • the first feeder (101 ) may be placed such that a phase center of the first radio wave is located at a first focal point (121 ), the first focal point (121) being a focal point of the offset reflector (108) and the dichroic filter (107) in the first frequency band.
  • the first mirror (105) and the second mirror (106) may be configured to focus the second radio wave at or near a second focal point (122), the second focal point (122) being a focal point of the offset reflector (108) and the dichroic filter (107) in the second frequency band.
  • the apparatus may comprise a support (112), the first mirror (105) and the second mirror (106) each being mounted to the support (112).
  • the first mirror (105) may be rotatable about a first axis (R1 ) and the second mirror (106) may be rotatable about a second axis (R2) which is orthogonal to the first axis (R1).
  • Rotating the first mirror about the first axis may displace the focus of the second radio wave along a curve (also known as quasi-parabolic Petzval’s curve) belonging to one principal curvature of the focal surface which passes through the focus of the offset reflector.
  • Rotating the second mirror about the second axis (R2) may displace the focus of the second radio wave along another curve belonging to the second principal curvature of that focal surface.
  • the combined action of rotating both the first and the second mirror controls, with two degrees of freedom, the focusing of the second radio wave to any point of the focal surface.
  • the support may comprise one or more flexible metallic foils arranged in solid contact with the first mirror and/or the second mirror.
  • the one or more flexible foils of metallic alloy can enable elastic deformation such that the first and the second mirror can each rotate back and forth in a reversible elastic motion. The motion will not be affected by wear and tear in the vicinity of the respective rotation axis passing through the respective mirror center.
  • the second feeder may comprise a dielectric feeder horn, for feeding the second radio wave towards the first mirror.
  • the directivity of the dielectric feeder horn is high enough towards the first mirror such that at the edges of the first mirror the level of illumination may be set as low as required for designing a low side-lobe antenna radiation pattern of the offset reflector.
  • the second feeder may further comprise a circular waveguide that supports any polarization of the second radio wave and comprises a two-groove circular choke (803) at the edge of a metal wall distal end.
  • the dielectric feeder horn comprises a portion embedded into an end section of the circular waveguide for operating as a broadband matching transformer.
  • the broadband matching transformer is a broadband impedance transformer for properly matching the fundamental mode TE11 of the electromagnetic broadband signal propagating into the metallic waveguide with the different type of fundamental hybrid mode HE11 propagating into the emitting and radiating sections of the dielectric horn.
  • the portion may be as short as a quarter wavelength.
  • the front-end section of the circular waveguide may comprise at least two concentric grooves, as deep as about a quarter wavelength, for improving horn directivity and efficiency.
  • the dielectric feeder horn comprises a hollow conical flare with axisymmetric walls progressively thinning along the flare from the matching transformer portion towards a distal radiating end of the dielectric feeder horn.
  • the hollow conical flare may have a length in the range of about 4 to 5 wavelengths.
  • the dielectric feeder horn comprises a low-dielectric constant constitutive material, preferably low-loss Teflon.
  • the walls of the hollow conical flare may be milled with an interleaved pattern of holes of about a quarter wavelength diameter and spacing, in order to gradually reduce their index of refraction towards the distal end of the dielectric feeder horn.
  • the dielectric feeder horn further comprises a solid cone of dielectric foam embedding the hollow conical flare.
  • the additional solid cone may provide an increased directivity using a dielectric foam of low dielectric constant, preferably a closed-cells foam with dielectric constant lower than 1 .1 and extremely low loss.
  • the length of the cone of dielectric foam may be about 13 wavelengths.
  • the diameter of the distal radiating end of the cone may be about 5 wavelengths.
  • the proximal end of this cone may be arranged and configured to fill the concentric grooves of the front-end section of the circular waveguide.
  • the cone of dielectric foam may have an extended length of about 15 wavelengths and the diameter of a distal radiating end of the foam cone may be proportionally increased to about 5.5 wavelengths, in order to keep the same directivity.
  • the second feeder further comprises a graded-index lens configured to guide and focus the second radio wave towards the first mirror for increasing the directivity of the dielectric feeder horn.
  • the graded-index lens allows setting the level of illumination at the mirror edges as low as required by the design of a low side-lobe antenna radiation pattern of the main reflector dish.
  • the graded-index lens comprises a coiled or rolled strip of dielectric material, wherein the strip of dielectric material defines an interleaved pattern of holes.
  • the strip of dielectric material is preferably made from Teflon.
  • the holes may have a diameter and spacing of a quarter wavelength.
  • the thickness of the strip may be half a wavelength.
  • the holes may be drilled at high speed on the planar sheet of the dielectric constituent material, along the thickness direction of the sheet.
  • the holes may be interleaved with a spacing of about quarterwavelength, wherein the pattern of interleaved holes controls a desired gradual variation of the refraction index inside the graded-index lens.
  • the first frequency band is a microwave band and the second frequency band is the E-band or the D-band or any higher frequency band.
  • the second frequency band any implementation form of the second dielectric feeder horn described above can be adopted, while, for the first microwave frequency band, a compact and flat dual polarization array feeder assembly, fed by two independent ports and a waveguide beam-forming network may be adopted together with a microwave band graded-index lens designed for radiation pattern directivity enhancement as described above.
  • the dichroic filter is a planar dichroic filter screen.
  • the planar dichroic filter screen may be either a multilayer surface, in which the broadband frequency selective filtering is accomplished by the regular, periodic pattern of metallic resonators on the surface or a single layer surface, in which the broadband frequency selective filtering is operated by the regular periodic pattern of multimode dielectric resonators on the surface.
  • the dichroic filter comprises a planar alldielectric screen.
  • the planar dichroic filter screen may be made of a background support matrix (117), wherein a triangular lattice of equal blind-holes (118) comprises a resonator (119) in each hole.
  • the resonator may be a ceramic multimode resonator (119), characterized by a pattern of seven holes (120).
  • the first mirror and/or the second mirror is a quasi-parabolic mirror.
  • the rotational movement of the first mirror and/or the second mirror may be motorized by means of a brushless moving solenoid actuator or by means of a piezoelectric actuator.
  • the first mirror and the second mirror are arranged in an offset Dragonian configuration such that a focal point of the first mirror (105) coincides with a phase center of the second feeder (102) and a focal point of the second mirror (106) coincides with a focus (122) of the offset reflector (108) and the dichroic mirror (107) for the second frequency band.
  • the first mirror has a first focal length and the second mirror has a second focal length f 2 , wherein the ratio between the first focal length and the second focal length f 2 obeys the following equation: wherein 9 denotes an offset angle of the first mirror and 9 2 denotes an offset angle of the second mirror.
  • a second aspect relates to a dual-band antenna comprising an offset reflector.
  • the offset reflector may be a parabolic or quasi-parabolic offset reflector.
  • the dual-band antenna comprises a feeder apparatus according to the first aspect for providing and focusing the first radio wave in the first frequency band at the first focal point of the offset reflector and for providing and focusing the second radio wave in the second frequency band at the second focal point of the offset reflector.
  • the offset reflector dish preferably has a focal ratio of about 0.7.
  • Fig. 1 a is a diagram illustrating a dual-band antenna according to an embodiment with a feed apparatus according to an embodiment
  • Fig. 1 b is a diagram illustrating an aspect of a dual-band antenna according to an embodiment with a feed apparatus according to an embodiment
  • Figs. 2a and 2b are diagrams illustrating the antenna radiation patterns in a first band of frequency versus two different edge-illumination taper of an offset reflector of a dual-band antenna according to an embodiment
  • Figs. 3a and 3b are diagrams illustrating aspects of frequency band diplexing scheme
  • Fig. 4a is a diagram illustrating aspects of frequency band diplexing scheme
  • Fig. 4b and 4c are diagrams illustrating an aspect of a dual-band antenna according to an embodiment with an all-dielectric dichroic filter according to an embodiment
  • Figs. 4d and 4e are diagrams illustrating the frequency diplexing performance in a second band of frequency and in a first band of lower frequency, respectively, with reference to an embodiment of all-dielectric dichroic filter shown in the Fig. 4b and 4c;
  • Fig. 5a is a diagram illustrating a dual-band antenna according to an embodiment with a feed apparatus according to an embodiment
  • Fig. 5b is a diagram illustrating a more detailed view of the feed apparatus of figure 5a;
  • Figs. 5c and 5d are diagrams illustrating a mirror adjustment mechanism of the feed apparatus of figure 5a;
  • Fig. 6 schematically shows an example of a mirror adjustment mechanism, illustrating a rotational axis R1 of the first mirror and a rotational axis R2 of the second mirror.
  • Figs. 7a, 7b, 8a and 8b are diagrams illustrating the antenna radiation patterns in a second band of frequency with reference to the limited-scan performances of the antenna of figure 5a relevant to the mirror adjustment operation;
  • Figs. 9a and 9b are diagrams illustrating a second band of high frequency feeder of a feed apparatus according to an embodiment
  • Figs. 10a and 10b are diagrams illustrating aspects of a first band of low frequency feeder of a feed apparatus according to an embodiment
  • Figs. 11a and 11 b are diagrams illustrating a second band of high frequency feeder of a feed apparatus according to an embodiment
  • Figs. 12a and 12b are diagrams illustrating aspects of a high frequency feeder horn of a second feeder of a feed apparatus according to an embodiment
  • Figs. 13a, 13b and 13c are diagrams illustrating a manufacturing method for manufacturing the graded-index lens, which is a component of a first feeder and/or a second feeder of a feed apparatus according to an embodiment.
  • a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa.
  • a corresponding device may include one or a plurality of units, e.g. functional units, to perform the described one or plurality of method steps (e.g. one unit performing the one or plurality of steps, or a plurality of units each performing one or more of the plurality of steps), even if such one or more units are not explicitly described or illustrated in the figures.
  • a specific apparatus is described based on one or a plurality of units, e.g.
  • a corresponding method may include one step to perform the functionality of the one or plurality of units (e.g. one step performing the functionality of the one or plurality of units, or a plurality of steps each performing the functionality of one or more of the plurality of units), even if such one or plurality of steps are not explicitly described or illustrated in the figures. Further, it is understood that the features of the various exemplary embodiments and/or aspects described herein may be combined with each other, unless specifically noted otherwise.
  • Figure 1 a shows a dual-band antenna 100 according to an embodiment with a feed apparatus according to an embodiment and an offset reflector 108 (herein also referred to as dish 108).
  • the reflector 108 may be a parabolic reflector or a quasi-parabolic reflector.
  • Figure 1b illustrates the offset configuration of the offset reflector 108.
  • the feed apparatus is configured to provide and focus a first radio wave in a first low frequency band at a first focal point 121 of the offset reflector 108 and to provide and focus a second radio wave in a second high frequency band at or near a second focal point 122 by means of the offset reflector 108 and the dichroic filter 107.
  • the first frequency band is a microwave band
  • the second frequency band is the E-band or the D-band or any higher frequency band.
  • the offset reflector dish 108 has a focal ratio of about 0.7.
  • the feed apparatus comprises a first feeder 101 configured to emit the first radio wave in the first frequency band with phase center at the first focal point 121 of the offset reflector 108 and a second feeder 102 configured to emit the second radio wave in the second frequency band above the first frequency band.
  • the feed apparatus comprises a first mirror 105 and a second mirror 106.
  • the first mirror 105 is configured to receive the second radio wave from the second feeder 102 and to reflect the second radio wave in the direction of the second mirror 106.
  • the second mirror 106 is configured to receive the second radio wave from the first mirror 105 and to focus the second radio wave phase center at the second focal point 122 of the combination of offset reflector 108 and dichroic filter 107.
  • the first mirror 105 and/or the second mirror 106 may be quasi- parabolic mirrors.
  • the first mirror 105 and the second mirror 106 are arranged in an offset Dragonian configuration such that in the steady neutral configuration without any mirror rotation the focal point of the first mirror 105 coincides with the phase center of the second feeder 102 and the focal point of the second mirror 106 coincides with the second focal point 122 of the offset reflector 108.
  • the first mirror 105 has a first focal length and the second mirror 106 has a second focal length f 2 , wherein the ratio between the first focal length and the second focal length f 2 obeys the following equation: wherein 9 denotes an offset angle of the first mirror 105 and 9 2 denotes an offset angle of the second mirror 106.
  • the feed apparatus further comprises a dichroic filter 107 configured to transmit the first radio wave from the first feeder 101 towards the offset reflector 108 and configured to receive the second radio wave from the second mirror 106 and to reflect the second radio wave towards the offset reflector 108.
  • the first focal point 121 corresponds to the focus of the offset reflector 108
  • the second focal point 122 corresponds to the mirroring action of the dichroic filter 107 combined with the offset reflector 108.
  • the dichroic filter 107 is a planar dichroic filter screen 107.
  • the planar dichroic filter screen 107 may be a multilayer surface, wherein the broadband frequency selective filtering is accomplished by a regular, periodic pattern of metallic resonators on the surface.
  • the planar dichroic filter screen 107 may be a single-layer surface, wherein the broadband frequency selective filtering is accomplished by a regular, periodic pattern of dielectric multimode resonators on the surface.
  • a dichroic filter 107 comprises a planar screen made of an all-dielectric background support matrix 117, wherein a triangular lattice of equal blind-holes 118 comprises in each hole a type of resonator 119, wherein this resonator may be a ceramic type multimode resonator 119, characterized by an holey pattern of seven holes 120.
  • the antenna 100 and/or the feed apparatus may further comprise absorbing material 109 and 110 arranged at suitable locations as well as a first radio unit 103 for driving the first low frequency feeder 101 and a second radio unit 104 for driving the second high frequency feeder 102.
  • Figures 2a and 2b are diagrams illustrating the relationship between the edge-illumination taper and the radiation pattern performance of the offset reflector 108 in the first low frequency band of the dual-band antenna 100 according to an embodiment. More specifically, figure 2a shows how the feed apparatus allows limiting the edge-illumination taper of the offset reflector 108 at an exemplary value of -12dB for achieving low close-in sidelobes, while figure 2b shows an even further reduction of nonethelessclose-in“ sidelobes achievable by the feed apparatus by means of a reasonable sacrifice of antenna efficiency (-27%) and with a corresponding reduction of gain (-1 .4dB), as a direct consequence of the further limitation of the illumination taper (-25dB) at the edges of the offset reflector dish 108.
  • the feed apparatus implements a frequency diplexing scheme for providing the dual band antenna 100 enabling independent optimization of the first feeder 101 for a lower microwave frequency band (e.g. 15-18-23-38 GHz) and the separate second feeder 102 for a millimeter waveband (e.g. E-band from 71 GHz up to 86GHz or D-band from 130GHz up to 175GHz).
  • a millimeter waveband e.g. E-band from 71 GHz up to 86GHz or D-band from 130GHz up to 175GHz.
  • the dichroic filter screen 107 behaves as a mirror for the rays of the second radio wave generated in the millimeter waveband by the second feeder 102.
  • the dichroic filter screen 107 is transparent for the rays of the first radio wave generated in the lower microwave band by the first feeder 101 .
  • a straight-forward combination of the configurations shown in figures 3a and 3b is shown in figure 4a for trying to compensate swaying motions of the offset reflector 108 by means of a simple one-axis rotation of the dichroic filter screen 107, wherein the axis of rotation lies within the offset-plane of the antenna.
  • FSS frequency selective surface
  • the embodiments disclosed herein employ the configuration of the first mirror 105 and the second mirror 106 as illustrated, for instance, in figure 1a.
  • the feed apparatus may be configured and/or may comprise further components for rotating the first mirror 105 about a first rotation axis R1 that passes through a center point of the first mirror 105 and/or for rotating the second mirror 106 about a second rotation axis R2 that is orthogonal to the first rotation axis R1 and passes through a center point of the second mirror 106.
  • Rotating the first mirror 105 displaces the focusing of the second radio wave along the curve (also known as quasi-parabolic Petzval’s curve) belonging to one principal curvature of the focal surface which passes through the focus 122 of the main offset reflector 108 combined with the dichroic filter 107 of the antenna 100.
  • Rotating the second mirror 106 displaces the focusing of the second radio wave along another curve belonging to the second principal curvature of this focal surface.
  • the combined action of rotating both the first and the second mirror 105, 106 displaces, with two degrees of freedom, the focusing point of the second radio wave on the focal surface.
  • FIG. 5a-d An embodiment of the antenna 100 and the feed apparatus, including a mechanism 112 for rotating the first mirror 105 and/or the second mirror 106, is shown in figures 5a-d.
  • Figures 6a and 6b show two extreme rotational positions of the second mirror 106 and the consequent opposite displacements near the second focus 122 of the bundle of rays, representing the re-focusing of the second radio wave phase centre operated by the mirrors 105 and 106.
  • Figures 7a and 7b are diagrams illustrating the radiation pattern performance and the optical aberrations computed for the whole antenna of figure 1 a when rotating the second mirror 106 at the positions shown in Fig. 6a and 6b.
  • the second radio wave emitted by the second feeder 102 at a phase center point and reflected by mirrors 105 and 106, can be focused at or near the second focal point 122, such that the second radio wave, after further reflections by the dichroic filter 107 and by the offset reflector 108, will have minimal spread, i.e. have nearly planar wavefronts and will propagate parallel or nearly parallel with the first radio wave along the axial direction of the offset reflector 108.
  • the new phase center point of the second radio wave can be moved at any arbitrary point located near the focal point 122, enabling a precise steering of the second radio wave beam radiation (after further reflection by the dichroic filter 107 and the offset reflector 108) around the axial direction of the offset reflector 108.
  • This beam steering of the second radio wave does not impair the far-field properties of the antenna radiation pattern envelope, provided that a limited angle of steering (i.e. a limited scanning angle) is concerned, comprised in a range of ⁇ 3 antenna beam-widths.
  • the mirrors 105 and 106 may each be rotated by a precise small angle about their respective rotational axis, i.e. about the axis R1 (for mirror 105) or R2 (for mirror 106). Therefore, a small rotation (less than ⁇ 3°) of mirror 105 about its axis R1 operates the steering of the second radio wave antenna beam along one direction (e.g. elevation), while, a small rotation (less than ⁇ 3°) of mirror 106 about its axis R2 operates the steering of the second radio wave antenna beam along an orthogonal direction (e.g.
  • Such elementary rotations of the mirrors may be properly coupled, i.e. rotation of the first mirror 105 about the axis R1 by an angle a can be combined with a rotation of the second mirror 106 about the axis R2 by an angle p, such that the final beam steering results a linear combination of these rotation angles:
  • Figures 8a and 8b illustrate the limited-scan capability of the antenna beam around the “boresight direction” of the axis of offset reflector 108, computed for the whole antenna of Fig. 1 a, when the second mirror 106 is set at the rotational positions of Fig. 6a and 6b.
  • the feed apparatus shown in figure 5a further comprises a support 112 (illustrated in the more detailed view of figure 5b) configured to support and rotate, by way of example, the first mirror 105, wherein the support 112 is a mechanism comprising one or more flexible metallic foils 111 a, 111 b arranged in solid contact with the first mirror 105.
  • the one or more flexible foils 111 a, 111b of metallic alloy enable elastic deformation, such that the first mirror 105 is supported and may rotate in a reversible elastic motion that is not affected by wear and tear in the vicinity of the rotation axis R1 passing through the center of the first mirror 105.
  • Typical rotation angles for the rotation of the first mirror 105 are usually within a range of less than ⁇ 5°.
  • Rotations of the first mirror 105 and/or the second mirror 106 may be motorized by a brushless moving solenoid actuator or by a piezoelectric actuator.
  • Further embodiments for controlling the position, i.e. to rotate the first mirror 105 and/or the second mirror 106, are disclosed in WO/2020/083478, which may be implemented by the antenna 100 and the feed apparatus and which are fully incorporated herein by reference.
  • Figure 9a is a diagram illustrating an embodiment of the high frequency second feeder 102 of the feed apparatus.
  • the second feeder 102 comprises a dielectric feeder horn 804 for feeding the second radio wave towards the first mirror 105.
  • the directivity of the dielectric feeder horn 804 is high enough towards the first mirror 105 such that at the edges of the first mirror 105 the level of illumination may be set as low as required for designing a low side-lobe antenna radiation pattern of the offset reflector 108.
  • the dielectric feeder horn 804 allows improving the radioelectric matching between the feeding circular waveguide 801 characterized by the TE11 fundamental mode of guided-wave propagation and the dielectric feeder horn 804 characterized by the HE11 hybrid mode of wave propagation and radiation. This may be achieved by a matching transformer 802 and/or a two-groove choke 803 at the edge of the solid wall of the circular waveguide 801 in order to sustain more efficiently the HE11 hybrid mode such that the directivity of the dielectric feeder 804 may be increased by up to 20%, while the corresponding gain may be increased by one dB.
  • the second feeder 102 comprises, in addition to the dielectric feeder horn 804 of figure 9a, a graded-index (GRIN) lens 805 configured to guide and focus the second radio wave towards the first mirror 105 for increasing the directivity of the dielectric feeder horn 804.
  • the graded-index lens 805 allows setting the level of illumination at the mirror edges as low as required by the design of a low side-lobe antenna radiation pattern of the main reflector dish 108.
  • the graded-index lens 805 may comprise a coiled or rolled strip of dielectric material 806, wherein the strip 806 of dielectric material defines an interleaved pattern of holes.
  • the strip 806 of dielectric material is preferably made from Teflon.
  • the holes may have a diameter and spacing of a quarter wavelength.
  • the thickness of the strip 806 may be half a wavelength.
  • the holes may be drilled at high speed on the planar sheet of the dielectric constituent material, along the thickness direction of the sheet.
  • the holes may be interleaved with a spacing of about quarter-wavelength, wherein the pattern of interleaved holes controls a desired gradual variation of the refraction index inside the graded-index lens 805.
  • Figures 10a and 10b are diagrams illustrating aspects of the first low frequency feeder 101 of the feed apparatus according to an embodiment.
  • the first low frequency feeder 101 comprises a compact dual- polarization planar array 900.
  • the array can comprise two separate interleaved 4x4 16-slot arrays 901 and 902 with orthogonal linear polarizations and corresponding independent rectangular waveguide ports 903 and 904.
  • the first low frequency feeder 101 may comprises a dielectric graded-index (GRIN) lens 905, as illustrated in figure 10b.
  • GRIN dielectric graded-index
  • the GRIN lens 905 of the first low frequency feeder 101 may comprise a coiled or rolled strip of dielectric material, wherein the strip of dielectric material defines an interleaved pattern of holes.
  • the strip of dielectric material is preferably made from Teflon.
  • the holes may have a diameter and spacing of a quarter wavelength at the first low frequency band.
  • the thickness of the strip may be half a wavelength at the first low frequency band.
  • the holes may be drilled at high speed on the planar sheet of the dielectric constituent material, along the thickness direction of the sheet.
  • the holes may be interleaved with a spacing of about quarter-wavelength at the first low frequency band, wherein the pattern of interleaved holes controls a desired gradual variation of the refraction index inside the graded-index lens 905.
  • FIGs 11 a and 1 1 b illustrate the second high frequency feeder 102 of the feed apparatus according to a variant of the embodiment shown in figures 9a and 9b.
  • the second high frequency feeder 102 does not comprise a GRIN lens (as in the embodiment shown in figure 9b).
  • a directivity enhancement of the second high frequency feeder 102 of the feed apparatus is achieved by additional dielectric cone 807, as shown in Fig. 11 a.
  • the dielectric cone 807 may have an axial length of up to about 13 wavelengths and may be made of a low density dielectric material having low losses and a dielectric constant lower than 1 .1 (that is, the corresponding refraction index is lower than 1 .05).
  • the dielectric cone 807 comprises a planar end section 808 on the radiating side.
  • the tip of the cone 807 is properly shaped in order to match well with the two grooves 803 present at the edge of the solid metal circular waveguide 801 .
  • figures 1 1 a and 1 1 b show an embodiment of the second high frequency feeder 102 of the feed apparatus, where the additional dielectric cone 807 is embedding the dielectric feeder horn shown in figures 9a and 9b
  • figures 12a and 12b show a further embodiment of the second high frequency feeder 102 of the feed apparatus, where the dielectric portion 804 of the embodiment shown in figures 9a and 9b has been removed.
  • the dielectric cone 807 preferably has an axial length of about 15 wavelengths.
  • Figures 13a, 13b and 13c are diagrams illustrating a manufacturing method applicable either for manufacturing the GRIN lens 805 of the second high frequency feeder 102 according to an embodiment or for manufacturing the GRIN lens 905 of the first low frequency feeder 101 according to an embodiment.
  • the disclosed system, apparatus, and method may be implemented in other manners.
  • the described embodiment of an apparatus is merely exemplary.
  • the unit division is merely logical function division and may be another division in an actual implementation.
  • a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed.
  • the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces.
  • the indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.
  • the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.
  • functional units in the embodiments of the invention may be integrated into one processing unit, or each of the units may exist alone physically, or two or more units are integrated into one unit.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

Deux ondes radio sont fournies à un réflecteur décalé (108) comme suit. Un premier dispositif d'alimentation (101) émet la première onde radio en direction du réflecteur décalé (108). Un second dispositif d'alimentation (102) émet une seconde onde radio en direction d'un premier miroir (105) qui réfléchit la seconde onde radio en direction d'un second miroir (106). Le second miroir (106) réfléchit la seconde onde radio en direction d'un filtre dichroïque (107). Le filtre dichroïque (107) passe la première onde radio et réfléchit la seconde onde radio en direction du réflecteur décalé (108). Les orientations du premier miroir (105) et du second miroir (106) peuvent être réglables.
PCT/EP2020/075625 2020-09-14 2020-09-14 Appareil d'alimentation en deux ondes radio dans un réflecteur décalé WO2022053160A1 (fr)

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PCT/EP2020/075625 WO2022053160A1 (fr) 2020-09-14 2020-09-14 Appareil d'alimentation en deux ondes radio dans un réflecteur décalé

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PCT/EP2020/075625 WO2022053160A1 (fr) 2020-09-14 2020-09-14 Appareil d'alimentation en deux ondes radio dans un réflecteur décalé

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2281660A1 (fr) * 1974-08-09 1976-03-05 Thomson Csf Dispositif muni d'une grille de filtrage
US4062018A (en) * 1973-12-21 1977-12-06 Kokusai Denshin Denwa Kabushiki Kaisha Scanning antenna with moveable beam waveguide feed and defocusing adjustment
US4260993A (en) * 1978-06-20 1981-04-07 Thomson-Csf Dual-band antenna with periscopic supply system
US4785310A (en) * 1986-08-14 1988-11-15 Hughes Aircraft Company Frequency selective screen having sharp transition
WO2020083478A1 (fr) 2018-10-24 2020-04-30 Huawei Technologies Co., Ltd. Système d'antenne à alimentation périscopique
US20200185835A1 (en) * 2017-06-30 2020-06-11 Huawei Technologies Co., Ltd. Antenna Feeder Assembly Of Multi-Band Antenna And Multi-Band Antenna

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062018A (en) * 1973-12-21 1977-12-06 Kokusai Denshin Denwa Kabushiki Kaisha Scanning antenna with moveable beam waveguide feed and defocusing adjustment
FR2281660A1 (fr) * 1974-08-09 1976-03-05 Thomson Csf Dispositif muni d'une grille de filtrage
US4260993A (en) * 1978-06-20 1981-04-07 Thomson-Csf Dual-band antenna with periscopic supply system
US4785310A (en) * 1986-08-14 1988-11-15 Hughes Aircraft Company Frequency selective screen having sharp transition
US20200185835A1 (en) * 2017-06-30 2020-06-11 Huawei Technologies Co., Ltd. Antenna Feeder Assembly Of Multi-Band Antenna And Multi-Band Antenna
WO2020083478A1 (fr) 2018-10-24 2020-04-30 Huawei Technologies Co., Ltd. Système d'antenne à alimentation périscopique

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