WO1990006004A1 - Antenne a reflecteur parabolique excentree - Google Patents

Antenne a reflecteur parabolique excentree Download PDF

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Publication number
WO1990006004A1
WO1990006004A1 PCT/AU1989/000485 AU8900485W WO9006004A1 WO 1990006004 A1 WO1990006004 A1 WO 1990006004A1 AU 8900485 W AU8900485 W AU 8900485W WO 9006004 A1 WO9006004 A1 WO 9006004A1
Authority
WO
WIPO (PCT)
Prior art keywords
reflector
antenna
receiver
feed
aperture
Prior art date
Application number
PCT/AU1989/000485
Other languages
English (en)
Inventor
Eric George Jones
Nicholas John Stevens
Original Assignee
Crooks Michell Peacock Stewart (Qld) Pty. Limited
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
Application filed by Crooks Michell Peacock Stewart (Qld) Pty. Limited filed Critical Crooks Michell Peacock Stewart (Qld) Pty. Limited
Publication of WO1990006004A1 publication Critical patent/WO1990006004A1/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
    • H01Q19/12—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 wherein the surfaces are concave
    • H01Q19/13—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 wherein the surfaces are concave the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination
    • H01Q19/132—Horn reflector antennas; Off-set feeding
    • 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
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/16—Reflecting surfaces; Equivalent structures curved in two dimensions, e.g. paraboloidal
    • H01Q15/161—Collapsible reflectors
    • H01Q15/162—Collapsible reflectors composed of a plurality of rigid panels

Definitions

  • THIS INVENTION relates to an improved antenna.
  • the invention is directed to an improved offset parabolic reflector antenna suitable for use in the microwave frequency range assignment for "C” Band and "Ku" Band satellite communications.
  • the paraboloidal reflectors used in known earth stations are usually of integral or one-piece construction, being made of metal or alternatively, plastic or fibreglass with a metallic reflective layer. As such reflectors may be 2 to 3 metres in diameter, they are difficult and cumbersome to handle and transport. In order to overcome these difficulties, composite reflector dishes have been developed. Such known composite reflectors typically are assembled from two halves to form a paraboloidal reflective surface. The reflector halves however, are still relatively cumbersome to handle and transport.
  • C-band is normally understood to be between 3.65 and 6.5 GHz
  • Ku-band is normally understood to be between 10.5 and 14.5 GHz
  • the known antennas are designed to operate in a single band, they are often limited to communicating with a single satellite, or a limited number of satellites. Cons quently, when access to alternate satellite communications is desired, it is necessary to install a different reflector dish as well as a different feed/receiver. Although multi-band antennas are known, such antennas are usually of complex and consequently expensive construction and hence unsuitable for most single consumer earth stations .
  • the present invention provides an antenna operable in at least two microwave frequency bands comprising: a reflector of paraboloidal shape; and support means connected to said reflector for mounting an antenna feed and/or receiver so that the antenna feed and/or receiver aperture is located offset relative to the aperture of the antenna reflector; characterised in that the ratio F/D is within the range of about 1 to about 1.12 and the ratio d/D is within the range of about 0.052 to about 0.11, where F is the focal length of the reflector, D is the diameter of the projected beam of the reflector and d is the displacement of the projected beam edge referenced to the focal plane of the axisy metric parent paraboloid of the reflector. (See Fig. 5).
  • the minimisation of F/D is desirable for economic and practical reasons, but on the contrary is undesirable on the grounds that the axial symmetry is improved with increasing F/D ratio.
  • the minimisation of d/D is desirable for the purpose, of minimising the order of beam asymmetry, but undesirable on the basis that increasing d/D allows feed horns to be accommodated without obstructing the projected aperture.
  • the specific design configuration of the offset parabolic reflector antenna of this invention results in an antenna which is suitable for satellite communication in a number of bands, such as the C and Ku bands, yet is of simple and economical construction.
  • F/D is about 1 while ' d/D is about 0.052.
  • the reflector is of composite construction, being assembled from four quadrant portions.
  • the reflector quadrants are preferably constructed of moulded plastics material, provided with a thin conductive layer. Surface distortion should be less than 0.25mm r.m.s.
  • the four quadrants can be dismantled and packaged in a relatively small container for ease of handling and transport.
  • each of the four quadrants of the reflector has a flange along each radial edge, the flanges of adjacent quadrants being in abutment when the quadrants are assembled, and held together by a U-shaped rib member to form the composite reflector.
  • complementary protrusions and recesses are provided in the mating faces of the edge flanges.
  • the projected diameter of the antenna is 2.6 metres, which is also equal to the focal length.
  • This antenna is suitable for transmitting and receiving operations in both the C-band and Ku-band.
  • the antenna is suitably fed by low flare angle horn feeds, typically corrugated horns, having a flare semi-angle of about 10 degrees, appropriate for the band of application.
  • the combination of versatile performance over a number of frequency bands, and compact portability when dissembled, give the antenna of this invention useful application in interactive communications with satellites yet the antenna can be erected on site at consumer level. Moreover, the simple construction of the antenna reduces the cost thereof and renders it suitable for single user earth stations.
  • FIG. 1 is a perspective view from the front of the antenna of the preferred embodiment of the invention.
  • Fig. 2 is a side elevation view of the antenna of Fig. 1,
  • Fig. 3 is a perspective view from the rear of the antenna of Fig. 1 ,
  • Fig. 4 is an exploded view of enlarged detail, of- abutting flanges of the reflector of Fig. 1, and
  • Fig. 5 is a schematic diagram illustrating configuration parameters of the antenna of Fig. 1.
  • the antenna of the preferred embodiment comprises a reflector 10 of paraboloidal shape.
  • the reflector 10 is of composite construction, being assembled from four different, ribbed reflector quadrants,
  • the reflector quadrants 10A, 10B, 10C, 10D The reflector quadrants 10A, 10B, 10C,
  • flanges 20A, 20B, 20C, 20D are provided with flanges 20A, 20B, 20C, 20D along their radial edges, and are clamped together at their abutting flanges by steel U-shaped ribs 16 and threaded fasteners 17.
  • the mating faces of the abutting flanges are provided with complementary slots 19 and protrusions 18 in order to ensure correct alignment of the quadrants, and to prevent relative movement thereof.
  • the reflector quadrant panels can be shipped in a package of small size, and assembled on site without the need for formal realignment as the jointing process minimises the possibility of assembly errors.
  • the steel ribs 16 form the main support structure for the reflector 10.
  • the support structure of the assembled reflector is pivotally mounted at 11 on a mounting pole 12
  • FIG. 3 An adjustable link 15 is connected between a rib 16 and the mounting post 12 to vary the elevation of the antenna, as can be seen more clearly in Fig. 2.
  • the reflector 10 is of pressed SMC (sheet moulding compound) moulded at temperatures in the order of 150 degrees C and at pressures in the order of 1500 psi.
  • SMC sheet moulding compound
  • the constituents of the SMC suitably incorporate doping to minimise the effects of distortion of the required quadrant profile. Such distortion is minimised in this process to a root mean square surface accuracy of 0.25mm.
  • the four dissimilar quadrant segments are typically manufactured separately in four discreet and dedicated moulds. If reinforced plastic is used as the material for the reflector, the weight of a 2.6-2.7 metre reflector plus backing structure is approximately 12-0 Kg. Such a reflector has a wind survivability of 67 metres per second.
  • An antenna feed and/or receiver 13 is mounted on an arm 14 which is connected to the steel backing ribs 16 of the antenna.
  • item 13 will be referred to as an antenna feed.
  • it will be apparent to those skilled in the art that it may in use be an antenna feed and/or receiver, as required.
  • the antenna feed 13 is mounted offset relative to the aperture of the reflector 10.
  • the feed support arm 14 is designed to position the antenna feed 13 so as to locate the feed component phase centre at the precise focal point. However, some adjustment potential is preferably included in the design to allow minimisation of crosspolar interference and optimisation of focal position.
  • the antenna is modelled using conventional techniques associated with offset paraboloidal antennas.
  • the principal parameters of focal length and angle of offset of the feed axis with respect to the parent paraboloid have been chosen to allow the antenna to be fed from low flare angle horns which do not obstruct the reflected wavefront and that also allow clearance of a minimum of a half wavelength to thereby minimise horn diffraction at the lower frequency constraint of the C- band.
  • the focal length (F) to projected .diameter (D) ratio is nominated as approximately unity, and the ratio of vertical displacement of projected aperture (d) -to projected diameter (D) is correspondingly about 0.052 (See Fig. 5).
  • the projected diameter of the antenna reflector of the preferred embodiment is 2.6m. This diameter has been chosen after evaluation of mean satellite operating parameters employed over the wider surface areas worldwide and with particular consideration to use in the thinner route applications of voice and data.
  • the antenna can be applied affordably in the TVRO arena for applications for Ku-band broadcast fringe and lower power video information and entertainment services.
  • the antenna is particularly suitable for earth stations in relatively underserved areas having low levels of technical expertise and limited financial resources .
  • the antenna is profiled to be fed, in use, from corrugated horns having a small flare semi-angle of about 10 degrees in order that the focal length can be retained within practical limits while maintaining the crosspolar performance within internationally acceptable levels. The use of small angle horns enables the offset angle to be minimised while still establishing the required removal of aperture blockage.
  • the technical result of this design selection is a versatile reflector antenna that can be used with appropriate feed horns to provide transmit and receive communications capability yet complying with the international standards of CCIR 580-1 with due regard for the performance of satellite earth station antennas after 1991.

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

Abstract

L'antenne décrite, qui est destinée à être utilisée pour les transmissions à la fois sur la bande C et sur la bande Ku (3,65 GHz à 14,5 GHz), comprend un réflecteur parabolique (10) avec organe de support (14) permettant un montage de l'alimentation de l'antenne et/ou du récepteur (13) de manière excentrée par rapport à l'ouverture du réflecteur. L'antenne est conçue pour que le rapport F/D soit compris entre 1 et 1,12 et pour que le rapport d/D soit compris entre 0,052 et 0,11, F étant la longueur focale, D le diamètre du faisceau projeté du réflecteur et d le déplacement du bord du faisceau projeté par rapport à l'axe focal du paraboloïde parent axisymétrique du réflecteur. L'antenne est alimentée de façon appropriée par un cornet d'alimentation cannelé à petit angle d'évasement.
PCT/AU1989/000485 1988-11-14 1989-11-14 Antenne a reflecteur parabolique excentree WO1990006004A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPJ141188 1988-11-14
AUPJ1411 1988-11-14

Publications (1)

Publication Number Publication Date
WO1990006004A1 true WO1990006004A1 (fr) 1990-05-31

Family

ID=3773498

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1989/000485 WO1990006004A1 (fr) 1988-11-14 1989-11-14 Antenne a reflecteur parabolique excentree

Country Status (1)

Country Link
WO (1) WO1990006004A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2288072A (en) * 1994-03-31 1995-10-04 Thomson Consumer Electronics Horn mounting arrangement for a satellite dish
EP0921590A2 (fr) * 1997-12-04 1999-06-09 Nec Corporation Antenne pour communiquer avec satellite à orbite basse
WO2009131177A1 (fr) * 2008-04-23 2009-10-29 マスプロ電工株式会社 Antenne parabolique décalée
CN102683855A (zh) * 2012-04-28 2012-09-19 深圳光启创新技术有限公司 一种便携式卫星天线

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3696435A (en) * 1970-11-24 1972-10-03 Bell Telephone Labor Inc Offset parabolic reflector antenna
US4232322A (en) * 1977-11-25 1980-11-04 Cselt - Centro Studi E Laboratori Telecomunicazioni S.P.A. Antenna having radiation pattern with main lobe of generally elliptical cross-section
EP0058215A1 (fr) * 1981-02-16 1982-08-25 Kathrein-Werke Kg Antenne pour la réception des ondes électro-magnétiques polarisées circulairement et émises par satellite de radiodiffusion
DE3530809A1 (de) * 1985-08-29 1987-03-05 Kolbe & Co Hans Parabolspiegelantenne

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3696435A (en) * 1970-11-24 1972-10-03 Bell Telephone Labor Inc Offset parabolic reflector antenna
US4232322A (en) * 1977-11-25 1980-11-04 Cselt - Centro Studi E Laboratori Telecomunicazioni S.P.A. Antenna having radiation pattern with main lobe of generally elliptical cross-section
EP0058215A1 (fr) * 1981-02-16 1982-08-25 Kathrein-Werke Kg Antenne pour la réception des ondes électro-magnétiques polarisées circulairement et émises par satellite de radiodiffusion
DE3530809A1 (de) * 1985-08-29 1987-03-05 Kolbe & Co Hans Parabolspiegelantenne

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CCIR Recommendation 580-1 (1982-1986). *
PROCEEDINGS OF THE IEEE, Volume 66, No. 12, December 1978 New York, A W RUDGE et al.: "Offset-Parabolic-Reflector Antennas: A Review", see pages 1592 to 1617. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2288072A (en) * 1994-03-31 1995-10-04 Thomson Consumer Electronics Horn mounting arrangement for a satellite dish
GB2288072B (en) * 1994-03-31 1998-02-18 Thomson Consumer Electronics Mechanism for mounting a receiving/transmitting horn in a satellite dish
EP0921590A2 (fr) * 1997-12-04 1999-06-09 Nec Corporation Antenne pour communiquer avec satellite à orbite basse
EP0921590A3 (fr) * 1997-12-04 1999-09-15 Nec Corporation Antenne pour communiquer avec satellite à orbite basse
WO2009131177A1 (fr) * 2008-04-23 2009-10-29 マスプロ電工株式会社 Antenne parabolique décalée
CN102683855A (zh) * 2012-04-28 2012-09-19 深圳光启创新技术有限公司 一种便携式卫星天线

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