EP0361294A1 - Drehsymmetrischer Antennenreflektor - Google Patents

Drehsymmetrischer Antennenreflektor Download PDF

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Publication number
EP0361294A1
EP0361294A1 EP89117371A EP89117371A EP0361294A1 EP 0361294 A1 EP0361294 A1 EP 0361294A1 EP 89117371 A EP89117371 A EP 89117371A EP 89117371 A EP89117371 A EP 89117371A EP 0361294 A1 EP0361294 A1 EP 0361294A1
Authority
EP
European Patent Office
Prior art keywords
antenna according
reflector
antenna
revolution
access
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.)
Withdrawn
Application number
EP89117371A
Other languages
English (en)
French (fr)
Inventor
Nhu Bui-Hai
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.)
Alcatel CIT SA
Original Assignee
Alcatel Telspace SA
Alcatel Transmission par Faisceaux Hertziens SA
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 FR8812459A external-priority patent/FR2637130B1/fr
Priority claimed from FR8812458A external-priority patent/FR2637129B1/fr
Priority claimed from FR8813781A external-priority patent/FR2640087B1/fr
Application filed by Alcatel Telspace SA, Alcatel Transmission par Faisceaux Hertziens SA filed Critical Alcatel Telspace SA
Publication of EP0361294A1 publication Critical patent/EP0361294A1/de
Withdrawn legal-status Critical Current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
    • 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
    • H01Q15/141—Apparatus or processes specially adapted for manufacturing reflecting surfaces

Definitions

  • the invention relates to an antenna with a reflector of revolution.
  • Such an antenna can be of several types: it can first of all be a monoreflective antenna.
  • Such an antenna comprises a reflector, generally of revolution, and a primary source generally of the horn type when the operating wavelength is centimeter, and of the dipole type with reflector when it is decimetric.
  • the efficiency of such an antenna is between 0.45 and 0.55.
  • the present invention consists in considerably reducing these influences.
  • Such an antenna can also be a cassegrain optic antenna.
  • the antennas with cassegrain optics with reflectors of revolution are well known. They include a main reflector of the paraboloidal type, a sub-reflector of either hyperboloidal or ellipsoidal shape, and a primary source.
  • the performance of a cassegrain antenna depends essentially on the mechanical qualities of the reflectors, namely: - accuracy of the profiles of the main reflector and the sub-reflector, - accuracy of the relative positioning between the two reflectors, - shape, quantity and positioning accuracy of the strands of the sub-reflector support.
  • the source which must be placed at the focal point located between the main reflector and the sub-sub-reflector, constitutes a certain mask for the waves emitted or received by the antenna.
  • the object of the invention is therefore also to solve these various problems.
  • an antenna with a reflector of revolution characterized in that this reflector is made of a material having a liquid phase and a solid phase and in that it is obtained by centrifugation of the material in its liquid phase, subsequently passed into its solid phase.
  • centrifugal reflector antenna makes it possible to gain: - about 0.3 dB on gain; - ten decibels on the diffuse level of radiation; - a contra-polar level lowered by approximately 10 to 15 decibels; - these performances being obtained with the same primary source.
  • a first variant of the antenna of the invention shown in FIGS. 1 and 2 is a monoreflective antenna comprising a primary source 10 here unipolar with an access flange 11, and a reflector 12 obtained by centrifugation of a material in a liquid form which was then solidified.
  • the source 10 is held in place by support struts 13, the cross section of which can be triangular, the apex of the triangle looking at the parabolic concave face of the reflector 12.
  • the invention therefore consists in replacing the conventional paraboloid reflector of revolution, manufactured either in glass laminate or in metal, by a paraboloid reflector of extremely low surface tolerance obtained by centrifugation of a material in liquid form such as molten plastic, or molten metal (copper or aluminum for example).
  • the reflector When the reflector is obtained by centrifugation of a plastic material (polyester for example), it then receives the deposit of a layer of metal (for example the shooping of a layer of zinc of a few tens of micrometers).
  • a layer of metal for example the shooping of a layer of zinc of a few tens of micrometers.
  • the radius of curvature and the focal length of such a reflector depend on the speed of centrifugation.
  • the tolerance of a reflector thus obtained is of the order of 0.1 mm.
  • the support pins 13 of the primary source are coated with a microwave absorbent 17.
  • the level of cross-polar radiation can thus drop from a few decibels to ten decibels.
  • the replacement, in an antenna, of a conventional paraboloidal reflector by a centrifugal paraboloidal reflector according to the invention of the same diameter and of the same focal length does not change the fixing and mounting system. Only the radio performance, which is much better, is changed.
  • an antenna with a centrifugal paraboloid reflector illuminated by a primary source placed at the focus such as: - antenna diameter: 3.60 m; - focal / diameter ratio: 0.43; - surface tolerance of the centrifugal reflector: ⁇ ⁇ 0.1 mm; - frequency band: 5.925 - 6.425 GHz.
  • the main reflector 110 is obtained by the so-called "centrifugation" technique defined above, either by using metal (copper or aluminum), or by depositing a metallic layer 126 on polyester by example.
  • the sub-reflector 111 can be obtained by mass machining. The accuracy of the paraboloidal profiles is therefore excellent: less than ⁇ 0.1 mm peak-to-peak.
  • a primary source 112 of corrugated horn type with exponential profile 118 It is defined to have a phase center 0 as stationary as possible which allows, in a wide frequency band, to maintain its excellent counter-polar performance.
  • a polarization duplexer 113 is arranged at the free end of the corrugated horn 118.
  • This polarization duplexer 113 operating according to two vertical and horizontal orthogonal polarizations, comprises a portion 114 in circular guide and two accesses 115 and 116 in rectangular guide, the second access 116 being aligned with the circular guide 114, a reflective plate 117 being disposed between the level of the first access 115 and the second access 116.
  • This duplexer therefore serves to group these two linear polarizations orthogonal vertical and horizontal: If a bipolar wave arrives by the entry of the circular guide 114, the wave with horizontal polarization strikes the reflective plate 117 which is parallel to it. It is reflected and passes through the first port 115 while the vertically polarized wave normally crosses (and perpendicularly) the reflective plate 117 and arrives at the second port 116.
  • the reciprocity is as follows: a wave arriving through the first port 115 reflects on the reflecting plate 117 and leaves through the circular guide 114.
  • the second access 116 is in a way "balanced" because the wave coming from this access attacks the circular guide 114 from the center. While the first access 115, attacking the circular guide 114 from the edge, is rather “asymmetrical” and unbalanced.
  • a lens 119 is located at the opening of the corrugated horn 118. Its role is to transform the spherical wave coming from the corrugated horn into a plane wave. It is of "dish-dish” shape, the hearth of this lens 119 being merged with the phase center 0 of the corrugated horn 118. It is made of dielectric material, for example polytetrafluoroethylene or "teflon".
  • the current high-performance cassegrain antennas can have main 110 and auxiliary 111 reflectors, with "shaped" profiles, that is to say, deformed in such a way that the phase d the reflected illumination of the main reflector 110 becomes practically very low (a few degrees instead of several tens of degrees), and that the amplitude reflected by the sub-reflector 111 is uniform.
  • the profile of the main reflector 110 must be paraboloidal due to the centrifugation technique. A "deformed" or shaped profile cannot therefore be obtained by this centrifugation.
  • the sub-reflector 111 which, being machined in the mass, can be shaped by changing the profile. The efficiency of this antenna is around 0.65 / 0.70.
  • the two reflectors 110, 111 can be kept as described above and in addition use such a lens 119 "shaped" in profile, by modifying its phase diagram to allow illumination of the main reflector 110 as close to equiphase illumination as possible.
  • the efficiency in this case will increase a little more, being around 0.67 - 0.72, that is to say that for a main reflector 110 centrifuged, and a sub-reflector 111 shaped, the lens 19 undergoes a conformation such that, for the waves emitted or received by the main reflector 110, it is practically equivalent to a conformation of this main reflector 110.
  • Such a variant of the antenna according to the invention can therefore be produced in particular in two ways - the first including: . a main reflector 110 centrifuged with a necessarily paraboloidal profile, . a sub-reflector 111 machined in the mass with a shaped profile but this solution corresponds to a "half conformation". - the second including . a main reflector 110 which is centrifuged and therefore has a paraboloid profile, . a sub-reflector 111 machined in the mass with a shaped profile, . and in addition a lens 119 with a profile shaped in phase.
  • the support of the sub-reflector 111 is constituted by four strands 120 (or arms) positioning and supporting this sub-reflector 111 with precision. They are advantageously placed "crosswise". These four arms 120 are fixed on the circumference of the main reflector 110. In this way the profile of the latter keeps a perfect paraboloidal continuity and is therefore not modified at the places where the four arms are fixed, as in the antennas of the known art. Likewise, the "cross" and not "X" profile of these four arms makes it possible not to influence the counter-polarization whose field is concentrated at 45 ° from the vertical and horizontal axes.
  • each arm 120 is preferably triangular (isosceles triangle), the apex looking at the paraboloidal face of the main reflector 110. In this way, any reflection of the radiated field on the four arms 120 will be minimized; which contributes to the contra-polar decrease.
  • the first access 115 is obtained by a "magic T" whose two arms 122 and 123 join two rectangular accesses 124 and 125 (of dimension of the waveguide) diametrically opposite on the circumference of the circular guide 114. This device is balanced.
  • the corrugated horn can be "folded" using a 45 ° plane as shown in FIG. 10, the horn being in a vertical position.
  • a spherical wave ⁇ 1 is formed at the opening of the horn 118. It is transformed into a plane wave ⁇ 2 after passing through the lens 119. This last wave ⁇ 2 after reflection on the paraboloidal sub-reflector 111, becomes a spherical wave ⁇ 3 which, reflecting on the main paraboloidal reflector 110, becomes a plane wave ⁇ 4 at the outlet of the antenna.
  • a plane wave ⁇ 4 coming from infinity is reflected on the main paraboloidal reflector 110. It becomes a spherical wave ⁇ 3 after reflection and strikes the paraboloidal sub-reflector 111. At the exit it becomes a plane wave ⁇ 2 which strikes the lens 119 . The latter transforms it into a spherical wave ⁇ 1 which propagates in the corrugated horn 118 and exits through the ports of the polarization duplexer 113.
  • - Frequency band 6.43 - 7.11 GHz
  • - Focal / diameter ratio 0.45
  • - Main reflector 110 manufactured by centrifugation this reflector being, for example, obtained by centrifugation of a plastic material then by deposition of a layer of metal: for example by shooping (or projection with a flame gun of a molten metal) a zinc layer of a few tens of micrometers, - Sub-reflector 111 manufactured by mass machining, for example in a metal such as aluminum; - Profile tolerance of the reflectors: ⁇ 0.1 mm; - Primary source 112: corrugated horn with exponential profile, opening 0.60 m in diameter and 0.90 m long; Lens 119 in the opening of the horn: 0.60 m in diameter; - Four
  • the primary source 112 may be square, rectangular or circular, respectively supplied by a waveguide of square, rectangular or circular section.
  • the sub-reflector 111 may not be confocal with the main reflector 110, but may be hyperboloidal or ellipsoidal.
  • the primary source is a horn not equipped with a lens.
  • the antenna efficiency is, in this case, lower but the characteristics remain very good thanks to the centrifugal main reflector.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)
  • Waveguide Aerials (AREA)
EP89117371A 1988-09-23 1989-09-20 Drehsymmetrischer Antennenreflektor Withdrawn EP0361294A1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
FR8812459 1988-09-23
FR8812459A FR2637130B1 (fr) 1988-09-23 1988-09-23 Antenne a optique cassegrain a haut rendement
FR8812458 1988-09-23
FR8812458A FR2637129B1 (fr) 1988-09-23 1988-09-23 Antenne a optique cassegrain a reflecteurs de revolution
FR8813781A FR2640087B1 (fr) 1988-10-20 1988-10-20 Antenne paraboloidale monoreflecteur
FR8813781 1988-10-20

Publications (1)

Publication Number Publication Date
EP0361294A1 true EP0361294A1 (de) 1990-04-04

Family

ID=27251696

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89117371A Withdrawn EP0361294A1 (de) 1988-09-23 1989-09-20 Drehsymmetrischer Antennenreflektor

Country Status (4)

Country Link
EP (1) EP0361294A1 (de)
JP (1) JPH02121506A (de)
AU (1) AU627493B2 (de)
CA (1) CA1314972C (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU627493B2 (en) * 1988-09-23 1992-08-27 Alcatel N.V. A circularly symmetrical reflector
EP1134838A1 (de) * 2000-03-14 2001-09-19 Lucent Technologies Inc. Antennengehäuse (Radom)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2986376B1 (fr) * 2012-01-31 2014-10-31 Alcatel Lucent Reflecteur secondaire d'antenne a double reflecteur
JP6143281B2 (ja) * 2013-03-04 2017-06-07 日本無線株式会社 レーダアンテナ
CN110429371B (zh) * 2019-08-07 2021-04-09 中国科学院新疆天文台 一种射电望远镜的馈电模式切换机构

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2551545A1 (de) * 1975-11-17 1977-05-26 Siemens Ag Drehsymmetrische cassegrain-antenne
GB2145569A (en) * 1980-06-03 1985-03-27 Mitsubishi Electric Corp Reflector antenna

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2412961A1 (fr) * 1977-12-22 1979-07-20 Thomson Csf Systeme d'antenne a balayage conique pour radar de poursuite
DE3380008D1 (en) * 1982-10-11 1989-07-06 Cambridge Electronic Ind Dish aerial
AU627493B2 (en) * 1988-09-23 1992-08-27 Alcatel N.V. A circularly symmetrical reflector

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2551545A1 (de) * 1975-11-17 1977-05-26 Siemens Ag Drehsymmetrische cassegrain-antenne
GB2145569A (en) * 1980-06-03 1985-03-27 Mitsubishi Electric Corp Reflector antenna

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
CONFERENCE RECORD - 1978 INTERNATIONAL CONFERENCE ON COMMUNICATIONS, Toronto, 4-7 juin 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" *
ELECTRONICS, vol. 35, no. 48, 30 novembre 1962, pages 134,136,138,140,142; J.W. DAWSON: "Spuncast plastics achieve reflector precision" *
GEC TELECOMMUNICATIONS, no. 40, 1975, pages 52-56; D.W. BOLWELL: "A high-efficiency Cassegrain antenna" *
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 87 (E-108)[965], 25 mai 1982; & JP-A-57 23 304 (NIPPON DENKI K.K.) 06-02-1982 *
PATENT ABSTRACTS OF JAPAN, vol. 8, no. 131 (E-251)[1568], 19 juin 1984; & JP-A-59 41 905 (FUJITSU K.K.>) 08-03-1984 *
THE MICROWAVE JOURNAL, vol. 4, no. 6, juin 1961, pages 74-76; J.R. JENNESS Jr. et al.: "Centrifugal forming of paraboloidal antennas" *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU627493B2 (en) * 1988-09-23 1992-08-27 Alcatel N.V. A circularly symmetrical reflector
EP1134838A1 (de) * 2000-03-14 2001-09-19 Lucent Technologies Inc. Antennengehäuse (Radom)
US6445360B2 (en) 2000-03-14 2002-09-03 Lucent Technologies Inc. Antenna structure for fixed wireless system

Also Published As

Publication number Publication date
AU627493B2 (en) 1992-08-27
CA1314972C (fr) 1993-03-23
AU4110389A (en) 1990-03-29
JPH02121506A (ja) 1990-05-09

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