EP0275062A2 - Antenne à faisceaux multiples - Google Patents

Antenne à faisceaux multiples Download PDF

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Publication number
EP0275062A2
EP0275062A2 EP88100249A EP88100249A EP0275062A2 EP 0275062 A2 EP0275062 A2 EP 0275062A2 EP 88100249 A EP88100249 A EP 88100249A EP 88100249 A EP88100249 A EP 88100249A EP 0275062 A2 EP0275062 A2 EP 0275062A2
Authority
EP
European Patent Office
Prior art keywords
reflector
antenna
partial
partial reflector
multibeam antenna
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.)
Granted
Application number
EP88100249A
Other languages
German (de)
English (en)
Other versions
EP0275062A3 (en
EP0275062B1 (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 electomagnetic 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.
  • a multibeam antenna of the present invention comprises a main reflector constituted by at least a first and a second partial reflector, the first partial reflector being defined by a part of a first paraboloid which has a first focus and a first axis or rotation, the second partial reflector being defined by a part of a second paraboloid which has a second focus and a second axis of rotation, the first and second partial reflectors being joined to each other with the first and second axis oriented in different directions from each other, a first primary radiator radiating an electomagnetic wave toward the main reflector to irradiate the first partial reflector and a part of the second reflector, and a second primary radiator for radiating an electromagnetic wave toward the main reflector to irradiate the second partial reflector and a part of the first partial reflector.
  • an exemplary multibeam anenna 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 antenns 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 embodying the present invention 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.
  • the partial reflectors 22A and 22B are joined to each other along a boundary line 32 such that the axis or 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 26 mainly irradiates a region 22b 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 22.
  • 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 the multibeam antenna in accordance with the present invention 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 invervted 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 electomagnetic 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 ovelapping 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 reflectors 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.
  • the subreflector 72 when the subreflector 72 is absent, among rays radiating from the focus Fa, those which are incident to the partial reflector (paraloloid B) 22B are reflected by the paraboloid B to become generally parallel to the axis 28.
  • the distances measured from the focus Fa to the plane which is parallel to the axis 28 by way of the paraboloid B are not the same as each other and involve some error.
  • that part (curved portion 72A) of the subreflector 72 which is associated with the paraboloid is provided with a predetermined curve which is slightly deviated from a plane.
  • 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.

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  • Aerials With Secondary Devices (AREA)
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 true EP0275062A2 (fr) 1988-07-20
EP0275062A3 EP0275062A3 (en) 1989-10-11
EP0275062B1 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

Country Status (4)

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

Cited By (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]
FR2642569A1 (fr) * 1989-01-31 1990-08-03 Televes Sa Support pour alimentateurs d'antennes paraboliques de reception multisatellite
FR2674377A1 (fr) * 1991-03-22 1992-09-25 Alcatel Espace Antenne radioelectrique a reflecteur multifocales.
FR2677815A1 (fr) * 1991-06-14 1992-12-18 Chapu Claude Reception de 3 satellites sur une parabole fixe.
FR2684809A1 (fr) * 1991-12-09 1993-06-11 Alcatel Espace Antenne passive multifaisceaux a reflecteur(s) conforme (s).
US5258767A (en) * 1989-03-14 1993-11-02 Kokusai Denshin Denwa Co., Ltd. Antenna system for shaped beam
EP0670609A1 (fr) * 1994-03-03 1995-09-06 SPACE ENGINEERING S.p.A. Antenne multifaisceau pour réception/émission simultanée de signaux de même fréquence de/à une ou plusieurs directions coplanaires
EP0845834A2 (fr) * 1996-12-02 1998-06-03 Space Systems/Loral, Inc. Méthode et appareil de réconfiguration des diagrammes d'antenne de rayonnement
US6258895B1 (en) * 1992-06-26 2001-07-10 The Procter & Gamble Company Polymers having spiro orthoester groups, process of manufacturing and using
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

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5357727A (en) * 1976-11-04 1978-05-25 Nec Corp Multiple shaped beam antenna
EP0028018A1 (fr) * 1979-10-24 1981-05-06 Western Electric Company, Incorporated Système d'antennes du type à réseau à déphasage
US4482897A (en) * 1982-06-28 1984-11-13 At&T Bell Laboratories Multibeam segmented reflector antennas

Family Cites Families (2)

* 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
JPS6094508A (ja) * 1983-10-28 1985-05-27 Nec Corp 成形ビ−ムアンテナ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5357727A (en) * 1976-11-04 1978-05-25 Nec Corp Multiple shaped beam antenna
EP0028018A1 (fr) * 1979-10-24 1981-05-06 Western Electric Company, Incorporated Système d'antennes du type à réseau à déphasage
US4482897A (en) * 1982-06-28 1984-11-13 At&T Bell Laboratories Multibeam segmented reflector antennas

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CONFERENCE RECORD 1978 INTERNATIONAL CONFERENCE ON COMMUNICATIONS, Toronto, 4th-7th June 1978, vol. 3, pages 35.4.1 - 35.4.5, IEEE, New York, US; H. YOKOI et al.: "Improving the radiation characteristics of aperture antennas" *
PATENT ABSTRACTS OF JAPAN, no. (E-78)[4354], page 4354 E 78; & JP-A-53 057 727 (NIPPON DENKI K.K.) 25-05-1978 *

Cited By (12)

* 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]
FR2642569A1 (fr) * 1989-01-31 1990-08-03 Televes Sa Support pour alimentateurs d'antennes paraboliques de reception multisatellite
US5258767A (en) * 1989-03-14 1993-11-02 Kokusai Denshin Denwa Co., Ltd. Antenna system for shaped beam
FR2674377A1 (fr) * 1991-03-22 1992-09-25 Alcatel Espace Antenne radioelectrique a reflecteur multifocales.
FR2677815A1 (fr) * 1991-06-14 1992-12-18 Chapu Claude Reception de 3 satellites sur une parabole fixe.
FR2684809A1 (fr) * 1991-12-09 1993-06-11 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
EP0670609A1 (fr) * 1994-03-03 1995-09-06 SPACE ENGINEERING S.p.A. Antenne multifaisceau pour réception/émission simultanée de signaux de même fréquence de/à une ou plusieurs directions coplanaires
EP0845834A2 (fr) * 1996-12-02 1998-06-03 Space Systems/Loral, Inc. Méthode et appareil de réconfiguration des diagrammes d'antenne de rayonnement
EP0845834A3 (fr) * 1996-12-02 1999-10-06 Space Systems/Loral, Inc. Méthode et appareil de réconfiguration des diagrammes d'antenne de rayonnement
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

Also Published As

Publication number Publication date
EP0275062A3 (en) 1989-10-11
AU605227B2 (en) 1991-01-10
CA1296422C (fr) 1992-02-25
DE3885308D1 (de) 1993-12-09
AU1016988A (en) 1988-07-14
EP0275062B1 (fr) 1993-11-03

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