EP0275062B1 - Antenne à faisceaux multiples - Google Patents

Antenne à faisceaux multiples Download PDF

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Publication number
EP0275062B1
EP0275062B1 EP19880100249 EP88100249A EP0275062B1 EP 0275062 B1 EP0275062 B1 EP 0275062B1 EP 19880100249 EP19880100249 EP 19880100249 EP 88100249 A EP88100249 A EP 88100249A EP 0275062 B1 EP0275062 B1 EP 0275062B1
Authority
EP
European Patent Office
Prior art keywords
reflector
antenna
paraboloid
subreflector
partial
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19880100249
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German (de)
English (en)
Other versions
EP0275062A3 (en
EP0275062A2 (fr
Inventor
Ryuichi C/O Nec Corporation Iwata
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP453587A external-priority patent/JPS63173404A/ja
Priority claimed from JP975387A external-priority patent/JPH0612853B2/ja
Application filed by NEC Corp filed Critical NEC Corp
Publication of EP0275062A2 publication Critical patent/EP0275062A2/fr
Publication of EP0275062A3 publication Critical patent/EP0275062A3/en
Application granted granted Critical
Publication of EP0275062B1 publication Critical patent/EP0275062B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/007—Antennas or antenna systems providing at least two radiating patterns using two or more primary active elements in the focal region of a focusing device

Definitions

  • the present invention relates to a multibeam antenna capable of communicating with a plurality of satellites which are positioned on stationary orbits at the same time.
  • a prior art multibeam antenna is constituted by a plurality of primary radiators and a single parabolic reflector for reflecting an electromagnetic wave radiating from each primary radiator in a different direction.
  • the primary radiators are located in the vicinity of the focus of the parabolic reflector, or paraboloid, at a suitable distance from each other.
  • a feeder section and a low-noise amplifier are associated with each of the primary radiators in such a manner as to extend along the axis of the antenna.
  • the deviation of the beams radiating from the parabolic reflector cannot be increased without increasing the distance between the primary radiators.
  • an increase in the distance between the nearby primary radiators necessarily results in the shift of the primary radiators away from the focus of the parabolic reflector, whereby the wavefront in the aperture plane of the parabolic reflector is disturbed to lower antenna gain.
  • Another problem with the prior art antenna is that the feeder section and amplifier section directly connected to each of the primary reflectors increase the length of antenna axis because they are arranged along the antenna axis (see e.g. US-A-3, 852, 763).
  • JF-A-53-57727 discloses a multiple shaped beam antenna with a main reflex mirror and partial reflex mirrors combined with the main reflex mirror. Relative positions and directions of the partial reflex mirrors and the primary radiators are selected so that the sectional shapes of a plurality of beams will be shaped into specific shapes deviated from a round shape.
  • the feeding of the main reflex mirror is perfomed by a plurality of primary radiators directly or via the associated reflex mirrors thereby realizing a plurality of shaped beam antennas.
  • the multibeam antenna according to the invention allows the length of an antenna axis to be reduced, suppresses the decrease in the phase performance in an aperture plane, and allows the reduction of the lateral dimension of a main reflector.
  • an exemplary multibeam antenna 10 includes a plurality of, three for example, primary radiators 12, 14 and 16, and a single parabolic reflector 18 which reflects each of electromagnetic waves radiated from the primary radiators in a different direction.
  • the primary radiators 12, 14 and 16 are located in the vicinity of the focus F of the parabolic reflector 18 at a suitable distance from each other.
  • a feeder section 12a and a low-noise amplifier 12b are associated with each of the primary radiators, as represented by the radiator 12 in the figure, and so arranged as to extend along the axis of the antenna.
  • a problem with the prior art antenna 10 is that an increase in the distance between the primary radiators 12, 14 and 16 causes them to be shifted away from the focus F, disturbing the wavefront in the aperture plane of the parabolic reflector 18 and, thereby, lowering antenna gain.
  • the feeder section and low-noise amplifier directly connected to each of the primary radiators extend in the axial direction of the antenna, increasing the overall length of the antenna axis.
  • a multibeam antenna is shown and generally designated by the reference numeral 20.
  • the antenna 20 comprises two-beam antenna which is made up of a main reflector 22 and two main radiators 24 and 26.
  • the main reflector 22 is constituted by two partial reflectors 22A and 22B which are defined by, respectively, a part of a paraboloid A and a part of a paraboloid B.
  • the partial reflectors 22A and 22B are joined to each other along a boundary line 32 such that the axis of rotation 28 of the paraboloid A and the axis of rotation 30 of the paraboloid B intersect each other.
  • Each of the axes of rotation 28 and 30 is inclined by an angle of ⁇ /2 relative to the center axis 34 of the antenna.
  • the foci Fa and Fb of the paraboloids A and B, respectively, which are located on the individual axes are spaced apart by a distance of 2d from each other.
  • the primary radiator 24 is positioned at the focus Fa on the axis 28 while the primary radiator 26 is positioned at the focus Fb on the axis 30.
  • the primary radiator 24 mainly irradiates a region 22a of the partial reflector 22A
  • the primary reflector 26 mainly irradiates a region 22b of the partial reflector 22B.
  • the regions 22a and 22b overlap each other as at 22c along the boundary line 32.
  • the region 22a is constituted by the partial reflector 22A and a part of the partial reflector 22B while the region 22b is constituted by the partial reflector 22B and a part of the partial reflector 22A.
  • the surface curve of the region 22a and that of the region 22b can be approximately equalized to the paraboloids A and B, respectively, by adequately selecting the distance 2d between the primary radiators 24 and 26.
  • rays radiating from the focus Fa are reflected by the region 22a of the main reflector 22 to become rays which are substantially parallel to the center axis 28 of the paraboloid A (radiation direction of beam A).
  • rays radiating from the focus Fb are reflected by the region 22b of the main reflector 22 to become rays which are substantially parallel to the center axis 30 of the paraboloid B (radiation direction of beam B).
  • electromagnetic waves coming out of the primary radiators 24 and 26 are radiated in different directions from each other, i.e., in the direction of the axis 28 and that of the axis 30.
  • the construction described above constitutes a two-beam antenna.
  • a second embodiment of a multibeam antenna is shown. While in the first embodiment the primary radiators 24 and 26 and their associated partial reflectors 22A and 22B are located on the same side with respect to the center axis 34 of the antenna 20, in the second embodiment the radiators 24 and 26 and their associated partial reflectors 22A and 22B are located at the opposite sides. Specifically, as shown in Figs. 3A and 3B, the partial reflector 22A associated with the primary reflector 24 is constituted by a part of the paraboloid B while the partial reflector 22B associated with the primary radiator 26 is constituted by a part of the paraboloid A. The rest of the second embodiment is identical in construction as the first embodiment.
  • the multibeam antenna 50 includes a flat reflector 52 which is located between the main reflector 22 and the two foci Fa and Fb.
  • the primary radiators 24 and 26 are located at, respectively, the inverted image points fa and fb of the foci Fa and Fb as defined by the flat reflector 52, the radiators 24 and 26 each facing the flat reflector 52.
  • electromagnetic waves radiating from the primary radiators 24 and 26 are individually reflected by the flat reflector 52 and, then, by the main reflector 22 to be radiated in two different directions.
  • the flat reflector 52 simply serves to bend the paths of electromagnetic waves and, therefore, the antenna 50 per se shares the same principle of operation as the antenna 20 of the first embodiment.
  • An advantage attainable with the flat reflector 52 is the reduction of the axial length of the antenna.
  • a multibeam antenna 60 is constructed to function as a three-beam antenna.
  • the main reflector 22 includes three partial reflectors 22A, 22B and 22C.
  • the partial reflectors 22A and 22B join each other along the boundary line 32, and the partial relectors 22B and 22C join each other along a boundary line 62.
  • the reflectors 22A, 22B and 22C are constituted by, respectively, a part of the paraboloid A, a part of the paraboloid B, and a part of a parabolic plane C.
  • the parabolic planes A, B and C have, respectively, foci Fa, Fb and Fc which are different from each other and axes of rotation 28, 30 and 64 which are different in direction from each other.
  • the primary radiators 24 and 26 and a primary radiator 66 are located at, respectively, the foci Fa, Fb and Fc of the axes 28, 30 and 64.
  • the principle of operation of the antenna 60 is the same as that of the first embodiment and, therefore, will not be described to avoid redundancy.
  • the overlapping portion 22c of the radiation regions on the main reflector in any of the first to fourth embodiments will be described in more detail.
  • the regions 22a and 22b can be aligned with the paraboloids A and B, respectively, by adequately selecting the distance 2d between, for example, the primary radiators 24 and 26 of Figs. 3A and 3B.
  • the alignment is only approximate and not precise. Specifically, that part of the region 22b which lies in the overlapping portion 22c has a surface curve which is defined by the paraboloid B, and that part of the region 22a which lies in the overlapping portion 22c has a surface curve which is defined by the paraboloid A.
  • phase error does not affect the usefulness of the first to fourth embodiments at all because the phase error is not noticeable, because the curve of the major part of the region 22b is defined by the paraboloid A, and because the curve of the region 22a is defined by the paraboloid B.
  • the decrease in the phase efficiency in the aperture plane which is ascribable to the phase error is lower than that ascribable to a phase error which would be caused if any of the primary radiators of the prior art multibeam antenna shown in Fig. 1 were deviated from the focus.
  • the regions 22b and 22a mainly use the partial reflectors 22A and 22B, respectively, i.e., the overlapping portion 22c be reduced. This, however, brings about another drawback that the lateral dimension of the main reflector 22 is increased.
  • a multibeam antenna 70 of Fig. 6 includes the main reflector 22, two primary radiators 24 and 26, and a single subreflector 72.
  • the main reflector 22 is constituted by the partial reflectors 22A and 22B which constitute, respectively, a part of the paraboloid A and a part of the paraboloid B.
  • the partial reflectors 22A and 22B are joined to each other along the boundary line 32 such that their center axes 28 and 30 intersect each other.
  • the subreflector 72 is located between the focus Fa of the paraboloid A which is positioned on the axis 28 and the focus Fb of the paraboloid B which is located on the axis 30.
  • the subreflector 72 is made up of three portions, i.e., a curved portion 72A close to the partial reflector 22A, a curved portion 72B close to the partial reflector 22B, and a flat intermediate portion 72C which interconnect the two curved portions 72A and 72B.
  • the surface curves of the curved portions 72A and B are individually determined as will be describe later.
  • the primary radiators 24 and 26 are located at, respectively, inverted image points F'a and F'b which are symmetrical to the foci Fa and Fb with respect to the subreflector 72, each radiating an electromagnetic wave toward the subreflector 72.
  • Fig. 9 is a view similar to Fig. 8, showing rays which are radiating from the other point F ⁇ b toward the axis 30. Details of Fig. 9 will be understood by analogy from Fig. 8.
  • the gist is that the surface curves of the curved portions 72A and 72B of the subreflector 72 are so selected as to compensate for or reduce the phase error in the event when electromagnetic waves reflected by the curved portions are radiated by their associated partial reflectors.
  • the size of the curved portion 72A and that of the curved portion 72B are dependent upon the sizes and focuses of their associated partial reflectors and the location of the subreflector 72. While the intermediate portion 72c is shown as being sized substantially the same size as the curved portions 72A and 72B, its size is variable depending upon, for example, the difference in focal length between the two paraboloids. By comparing Figs. 8 and 9, it will be understood that that area of the subreflector 72 to which the rays radiating from the point F ⁇ a and those radiating from the point F ⁇ b are incident is included in the intermediate portion 72C.
  • the subreflector 24 is capable of simultaneously compensating for phase errors which occur on the main reflector 22 with respect to the two different directions of radiations. Consequently, since that part of an electromagnetic wave radiating from the primary radiator 24 which is incident to the partial reflector 22B is compensated for in phase error, the limitation that, for example, the wave from the radiator 24 should mainly use the partial reflector 22A is eliminated. Hence, as shown in Figs. 8 and 9, the same region of the main reflector 22 can be shared by two different beams, promoting the decrease in the lateral dimension of the main reflector 22.
  • the foregoing description has concentrated on a situation wherein a plurality of focuses and the axes of rotation of a plurality of paraboloids are positioned in the same plane, such is only illustrative and may be replaced with a situation wherein, for example, the axes 28 and 30 of the paraboloids A and B, respectively, are in a distorted relationship. Specifically, the axes 28 and 30 may each be extended in any desired direction other than the same plane.
  • focal lengths of the paraboloids may not be equal to each other, and the contour of the main reflector is open to choice.
  • the present invention provides a highly efficient multibeam antenna despite that nearby ones of a plurality of radiation regions which are defined on a single main reflector overlap each other. This is because the curve of each radiation region is provided with substantially the same paraboloid as the surface curve of a radiation region which is defined on a single main reflector and, hence, each of the radiation regions can be regarded as a parabolic reflector which is independent of the others.
  • Another advantage attainable with the present invention is that the length of antenna axis can be reduced by transmitting electromagnetic radiations from a plurality of primary radiators indirectly to a main reflector by way of a single flat reflector.
  • a subreflector capable of compensating for phase errors particular to the radiation of electromagnetic waves by a main reflector is interposed between the main reflector and primary radiators, whereby the decrease in the phase efficiency in the aperture plane is suppressed. Since phase errors are compensated for by the subreflector as stated, it is not necessary to accurately match the primary reflectors with partial reflectors which constitute the main reflector and, therefore, the lateral dimension of the main reflector can be reduced.

Landscapes

  • Aerials With Secondary Devices (AREA)

Claims (2)

  1. Antenne à faisceaux multiples comprenant:
    - un réflecteur principal (22) constitué d'au moins un premier et un second réflecteur partiel (22A, 22B), ledit premier réflecteur partiel (22A) étant défini par une partie d'une première paraboloïde qui présente un premier foyer (Fa) et un premier axe de rotation, ledit second réflecteur partiel (22B) étant défini par une partie d'une seconde paraboloïde qui présente un second foyer (Fb) et un second axe de rotation, lesdits premier et second réflecteurs partiels étant réunis l'un à l'autre avec lesdits premier et second axes orientés dans des directions différentes l'une de l'autre;
    caractérisée en ce que :
    a) un sous-réflecteur (72) est situé entre ledit réflecteur principal et lesdits premier et second foyers,
    b) un premier et un second radiateur primaire (24, 26) sont placés, respectivement, à un premier et à un second point d'image inversée (F'a, F'b) qui sont symétriques, respectivement, desdits premier et second foyers par rapport audit sous-réflecteur, lesdits premier et second radiateurs primaires rayonnant chacun une onde électromagnétique de manière indirecte vers ledit réflecteur principal via ledit sous-réflecteur;
    c) ledit sous-réflecteur comprend une première partie incurvée (72A) située sur le même côté que ledit premier réflecteur partiel qui est placé sur un côté par rapport à l'axe de ladite antenne, une seconde partie incurvée (72B) située sur le même côté que ledit second réflecteur partiel qui est placé sur l'autre côté par rapport audit axe, et une partie intermédiaire (72C) interconnectant lesdites première et seconde parties incurvées, et
    d) ladite partie intermediaire (72C) a une surface plate.
  2. Antenne à faisceaux multiples selon la revendication 1, dans laquelle lesdites première et seconde parties incurvées ont des courbes de la surface sélectionnées chacune de façon à compenser une erreur de phase qui se produit lorsqu'une onde électromagnétique réfléchie par ladite première ou ladite seconde partie incurvée rayonne via lesdits premier ou second réflecteurs partiels.
EP19880100249 1987-01-12 1988-01-11 Antenne à faisceaux multiples Expired - Lifetime EP0275062B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP453587A JPS63173404A (ja) 1987-01-12 1987-01-12 マルチビ−ムアンテナ
JP4535/87 1987-01-12
JP9753/87 1987-01-19
JP975387A JPH0612853B2 (ja) 1987-01-19 1987-01-19 マルチビ−ムアンテナ

Publications (3)

Publication Number Publication Date
EP0275062A2 EP0275062A2 (fr) 1988-07-20
EP0275062A3 EP0275062A3 (en) 1989-10-11
EP0275062B1 true EP0275062B1 (fr) 1993-11-03

Family

ID=26338338

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880100249 Expired - Lifetime EP0275062B1 (fr) 1987-01-12 1988-01-11 Antenne à faisceaux multiples

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EP (1) EP0275062B1 (fr)
AU (1) AU605227B2 (fr)
CA (1) CA1296422C (fr)
DE (1) DE3885308D1 (fr)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2227609A (en) * 1989-01-30 1990-08-01 David James George Martin Double aerial [daerial]
ES1008936Y (es) * 1989-01-31 1989-12-16 Televes S.A. Soporte para alimentadores de antenas parabolicas de recepcion multisatelite.
US5258767A (en) * 1989-03-14 1993-11-02 Kokusai Denshin Denwa Co., Ltd. Antenna system for shaped beam
FR2674377B1 (fr) * 1991-03-22 1993-06-04 Alcatel Espace Antenne radioelectrique a reflecteur multifocales.
FR2677815B1 (fr) * 1991-06-14 1994-03-18 Claude Chapu Reception de 3 satellites sur une parabole fixe.
FR2684809B1 (fr) * 1991-12-09 1994-01-21 Alcatel Espace Antenne passive multifaisceaux a reflecteur(s) conforme (s).
US6258895B1 (en) * 1992-06-26 2001-07-10 The Procter & Gamble Company Polymers having spiro orthoester groups, process of manufacturing and using
IT1271871B (it) * 1994-03-03 1997-06-09 Space Eng Srl Antenna multifascio in grado di ricevere/trasmettere segnali alla stessa frequenza, da/verso piu' direzioni coplanari, simultaneamente.
US5945960A (en) * 1996-12-02 1999-08-31 Space Systems/Loral, Inc. Method and apparatus for reconfiguring antenna radiation patterns
RU2694813C1 (ru) * 2018-10-10 2019-07-17 Федеральное государственное бюджетное учреждение наук Институт проблем машиноведения Российской академии наук (ИПМаш РАН) Способ формирования отражающих зеркальных поверхностей антенны космического радиотелескопа
WO2024044956A1 (fr) * 2022-08-30 2024-03-07 华为技术有限公司 Antenne et dispositif de communication

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3852763A (en) * 1970-06-08 1974-12-03 Communications Satellite Corp Torus-type antenna having a conical scan capability
JPS5357727A (en) * 1976-11-04 1978-05-25 Nec Corp Multiple shaped beam antenna
US4259674A (en) * 1979-10-24 1981-03-31 Bell Laboratories Phased array antenna arrangement with filtering to reduce grating lobes
US4482897A (en) * 1982-06-28 1984-11-13 At&T Bell Laboratories Multibeam segmented reflector antennas
JPS6094508A (ja) * 1983-10-28 1985-05-27 Nec Corp 成形ビ−ムアンテナ

Also Published As

Publication number Publication date
CA1296422C (fr) 1992-02-25
AU605227B2 (en) 1991-01-10
DE3885308D1 (de) 1993-12-09
AU1016988A (en) 1988-07-14
EP0275062A3 (en) 1989-10-11
EP0275062A2 (fr) 1988-07-20

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