EP0017589A1 - In einem Radom eingebaute Cassegrain-Antenne - Google Patents

In einem Radom eingebaute Cassegrain-Antenne Download PDF

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Publication number
EP0017589A1
EP0017589A1 EP80400447A EP80400447A EP0017589A1 EP 0017589 A1 EP0017589 A1 EP 0017589A1 EP 80400447 A EP80400447 A EP 80400447A EP 80400447 A EP80400447 A EP 80400447A EP 0017589 A1 EP0017589 A1 EP 0017589A1
Authority
EP
European Patent Office
Prior art keywords
radome
reflector
fixed
cassegrain
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.)
Withdrawn
Application number
EP80400447A
Other languages
English (en)
French (fr)
Inventor
François Gautier
Pierre Crochet
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.)
Thales SA
Original Assignee
Thomson CSF 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
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0017589A1 publication Critical patent/EP0017589A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
    • H01Q1/425—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising a metallic grid
    • 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
    • H01Q19/195—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 a reflecting surface acts also as a polarisation filter or a polarising device

Definitions

  • the present invention relates to microwave antennas of the Cassegrain type mounted inside a radome.
  • the antenna according to the invention aims to remedy these drawbacks according to the invention, the fixed curved reflector is fixed by one or more points of its periphery to the wall of the radome by any fixing means, this arrangement having the effect of reducing of the total weight and an increase of the useful surface the main result of which is an increase in total antenna gain.
  • Figure 1 shows a Cassegrain antenna mounted in a radome according to the prior art. It comprises a radome 3, inside which is located a source 1 radiating a polarized electromagnetic wave, oriented in such a way that its emission direction coincides with the axis of symmetry of the radome, a 2 plane reflector reflecting the waves. by rotating the polarization by 90 °, a second reflector 4 polarization filter and mounted on a support 5, itself rigidly positioned by a fixing means 6.
  • the reflector 4 is constituted by a network of parallel metallic wires which are bonded to a substrate 5 designed so as to avoid parasitic reflections. This is achieved by using a substrate of the "sandwich" type, that is to say composed of two films with high dielectric constant surrounding a plate of low dielectric constant and whose thickness is , celebrating the wavelength emitted by the source 1. Its shape, for example, is a hyperboloid or a paraboloid of revolution.
  • This reflector 4 has drawbacks due to both the material used and its physical design.
  • the material with a low dielectric constant is fragile and its precise machining is delicate and the bonding of the metallic wires constituting the reflector 4, which also requires great precision, can be the source of parasitic reflections due to the adhesive which can mismatch the substrate 5 due to slight variations in thickness.
  • the reflector 4 and substrate 5 assembly requires a particular support 6 which provides it with good mechanical rigidity.
  • This support is for example made up of a cylinder of revolution produced according to the same structure as the substrate 5.
  • Such a support has the disadvantage, in addition to its construction difficulties, of reducing the useful surface of the reflector and therefore the gain of the 'antenna.
  • the invention aims to remedy these defects of the prior art.
  • Figure 2 shows a Cassegrain mid-round antenna mounted in a radome. It takes up the elements of FIG. 1 by removing the support 6 from the fixed reflector 4 and possibly adding thereto means for absorbing or filtering 8 electromagnetic waves and means 9 for fixing the stationary reflector 4 on the radome 3.
  • the reflector 4 is directly fixed to the radome 3 thus giving a larger useful surface and therefore an increase in the gain.
  • Means 8 for absorbing or filtering electromagnetic waves can optionally be placed around the Cassegrain antenna, on the walls of the radome 3 limited by the reflector 4, in order to avoid parasitic reflected waves and waves whose polarization n is not in a defined direction.
  • the reflector 4 used in the device according to the invention is a metal polarization filter with slot, of which FIG. 3 shows an exemplary embodiment.
  • This type of filter is known and we will only quickly recall its use. We can usefully refer to the article on these filters published in the IEEE review on pages 1 to 6 of the January 1973 issue, by CHEN.
  • It consists of a metal plate pierced with slots 7 of width a and length b which determine the resonance frequency. These slots 7 are arranged in several parallel rows such that for two successive rows the slots are for example staggered. The interval between two slots in the same row is constant and denoted x and the interval between two rows is Ay.
  • An angle 6 determines the orientation of the diagonal alignment due to the staggered arrangement of the slots. This angle is for example chosen to be equal to .
  • the set of these slots determines a polarization filter such that the waves polarized in the direction Y'Y are fully reflected, and those in the direction X'X pass through the filter without attenuation.
  • this type of reflector comes from the ease of machining the slots, from the forming of the reflector, for example by stamping, and especially from its rigidity allowing the removal of the substrate 5 and thus the disadvantage of the stray reflections due to its presence and to the unevenness of the gluing of the metallic wires. This better adjustment precision and stability over time improves the characteristics of the antenna. In addition, its small thickness makes it possible to limit the effects of diffusion of the edges of this reflector 4. Finally, this type of filter is more selective in frequency and its use in Cassegrain antennas integrated into a radome 3 can contribute to reducing the interference coming from frequencies. neighbors.
  • metal polarization filters with slots constitutes a preferred example, which does not prevent the antenna from being produced with any type of reflector of equal rigidity giving the same results as polarization filters.
  • the fixing of the reflector 4 on the radome 3 can be carried out by any means 9 such as for example a screwing or direct bonding on the radome.

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  • Aerials With Secondary Devices (AREA)
EP80400447A 1979-04-09 1980-04-03 In einem Radom eingebaute Cassegrain-Antenne Withdrawn EP0017589A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7908966 1979-04-09
FR7908966A FR2454190A1 (fr) 1979-04-09 1979-04-09 Antenne cassegrain montee dans un radome

Publications (1)

Publication Number Publication Date
EP0017589A1 true EP0017589A1 (de) 1980-10-15

Family

ID=9224141

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80400447A Withdrawn EP0017589A1 (de) 1979-04-09 1980-04-03 In einem Radom eingebaute Cassegrain-Antenne

Country Status (2)

Country Link
EP (1) EP0017589A1 (de)
FR (1) FR2454190A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003026065A1 (en) * 2001-09-14 2003-03-27 The Boeing Company Reflector assembly disposed within a radome

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1584348A (de) * 1968-07-16 1969-12-19
US4070678A (en) * 1976-04-02 1978-01-24 Raytheon Company Wide angle scanning antenna assembly
NL7809306A (nl) * 1977-09-13 1979-03-15 Marconi Co Ltd Antennesystemen voor op de grond geplaatste radarappa- ratuur.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1584348A (de) * 1968-07-16 1969-12-19
US4070678A (en) * 1976-04-02 1978-01-24 Raytheon Company Wide angle scanning antenna assembly
NL7809306A (nl) * 1977-09-13 1979-03-15 Marconi Co Ltd Antennesystemen voor op de grond geplaatste radarappa- ratuur.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003026065A1 (en) * 2001-09-14 2003-03-27 The Boeing Company Reflector assembly disposed within a radome
US6570540B2 (en) 2001-09-14 2003-05-27 The Boeing Company Reflector assembly for minimizing reflections of electromagnetic energy from an antenna disposed within a radome
US6856295B2 (en) 2001-09-14 2005-02-15 The Boeing Company Attenuation apparatus for minimizing reflections of electromagnetic energy from an antenna disposed within a radome

Also Published As

Publication number Publication date
FR2454190B1 (de) 1983-05-20
FR2454190A1 (fr) 1980-11-07

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Designated state(s): DE GB IT

17P Request for examination filed

Effective date: 19801029

STAA Information on the status of an ep patent application or granted ep patent

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18W Application withdrawn

Withdrawal date: 19830820

RIN1 Information on inventor provided before grant (corrected)

Inventor name: GAUTIER, FRANCOIS

Inventor name: CROCHET, PIERRE