EP0145510A1 - Antenne - Google Patents

Antenne Download PDF

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Publication number
EP0145510A1
EP0145510A1 EP84401723A EP84401723A EP0145510A1 EP 0145510 A1 EP0145510 A1 EP 0145510A1 EP 84401723 A EP84401723 A EP 84401723A EP 84401723 A EP84401723 A EP 84401723A EP 0145510 A1 EP0145510 A1 EP 0145510A1
Authority
EP
European Patent Office
Prior art keywords
filter
radar
aerial
axis
radiation
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
EP84401723A
Other languages
English (en)
French (fr)
Other versions
EP0145510B1 (de
Inventor
Claude Aubry
Jean Bouko
Serge Drabowitch
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 EP0145510A1 publication Critical patent/EP0145510A1/de
Application granted granted Critical
Publication of EP0145510B1 publication Critical patent/EP0145510B1/de
Expired legal-status Critical Current

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Classifications

    • 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
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices

Definitions

  • the invention mainly relates to a method making it possible to reduce the amplitude of the microwave energy reflected in the axis of an aerial, in particular of a radar and the radar using such a method.
  • the invention proposes to place in a radar aerial with a non-zero inclination relative to its axis, a frequency selective filter.
  • a frequency selective filter reflects the radiation of the enemy radar, according to the laws of Descartes, without significantly affecting the radiation of the radar where it is placed, since they work at different frequencies.
  • the energy returned in the axis of the air, to the enemy radar is considerably reduced.
  • the invention relates mainly to a method for reducing the amplitude of the microwave energy reflected in the axis of an aerial from an incident wave, characterized in that a selective filter is placed on the axis of the air and inclined relative to it, the selective filter reflecting microwave energy incident, and not significantly affecting the microwave energy emitted by said aerial.
  • the invention relates mainly to a radar characterized in that it comprises a source of microwave radiation and an aerial, the aerial comprising a frequency selective filter, arranged on the axis of the aerial and inclined relative to the latter .
  • FIGS. 1 to 3 the same references have been used to designate the same elements.
  • a radar 1 of conventional type receives, on an axis 3 of its aerial, incident electromagnetic radiation 4. As illustrated by the line 41, the radiation 4, arriving on the aerial 1, is focused on a source 5 of microwave radiation from the radar 1. The radiation is reflected on the source 5. Thus the reflected radiation 14 is in the axis of the aerial 1 with a very large amplitude.
  • the equivalent area in the axis of the air 1 is proportional to: SxGxR 2 , S being the area of the opening of the air, G being the gain in the axis of the air at the frequencies of the enemy radar , R 2 being the power reflection coefficient of the source 5.
  • the radar It is a tracking radar telepoint.
  • the telepoint radar 11 follows the movement of a missile 2.
  • a main lobe 7 of the radar 11 permanently lights the missile 2.
  • the missile 2 is permanently on the axis 3 of the aerial of the radar 11.
  • the missile 2 comprises an active seeker, it emits electromagnetic radiation 4 which arrives in the axis 3 of the radar 11.
  • a filter 6 inside the aerial of the radar 11. The filter 6 is such that it reflects the radiation 4, without affecting the radiation emitted by the radar 11. The normal to the filter 6 is not confused with the axis 3.
  • an axis 8 of the reflected radiation 40 forms an angle G with the axis 3.
  • the angle of the normal to the filter 6 and of the axis 3 is sufficient so that no energy is returned by the filter 6 in the direction of the missile 2.
  • Such a value of 9 takes into account the fact that the radiation 40 not being focused by the radar 11 is dispersed.
  • Such a filter 6 makes it possible to reduce for example by 20 decibels the gain G along the axis 3 of the aerial 11 at the frequencies of the enemy radar.
  • the filter 6 must reflect the radiation 4 of FIG. 2, without notably affecting the radiations of the main lobe 7 emitted by the source 5 of FIG. 2.
  • the radar according to the invention works with a frequency different from that of the seeker of the missile 2.
  • the telepoint uses the X band while a filter 6 is used which can reflect the energies included in the bands KU, KA and W.
  • the filter 6 can be either of the low-pass type or of the band-pass type.
  • the filter 6 is a dichroic mirror.
  • a dichroic low-pass mirror has been described in the patent filed by Applicant on December 18, 1981 published under number 2,518,828.
  • Such a filter comprises three low-loss dielectric plates 10, 12, 13 separated by two arrays of metal rectangles 44 and 15.
  • the filter 6 can be permanently placed, for example as a radome, in front of the source 5. In an alternative embodiment, there is a set of filters 6. The filter 6 is placed according to for example the theater of operation, and therefore according to the radiation frequency band of the opposing missile.
  • one of these filters 6 is set up in real time in front of the source 5, after the detection of electromagnetic radiation 4 by means not shown.
  • the filter 6 chosen will be best suited to reflect this radiation.
  • the invention is not limited to radar aerials.
  • the invention applies whenever there is a device focusing and reflecting the electromagnetic radiation of an opposing radar.
  • the method according to the invention applies in particular to radio-relay systems, as well as to antennas for connection with telecommunications satellites.

Landscapes

  • Aerials With Secondary Devices (AREA)
EP19840401723 1983-09-09 1984-08-28 Antenne Expired EP0145510B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8314404A FR2551921B1 (fr) 1983-09-09 1983-09-09 Procede permettant de reduire l'amplitude de l'energie hyperfrequence reflechie dans l'axe d'un aerien, radar et aerien de station de communication avec satellite utilisant un tel procede
FR8314404 1983-09-09

Publications (2)

Publication Number Publication Date
EP0145510A1 true EP0145510A1 (de) 1985-06-19
EP0145510B1 EP0145510B1 (de) 1989-11-02

Family

ID=9292100

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840401723 Expired EP0145510B1 (de) 1983-09-09 1984-08-28 Antenne

Country Status (3)

Country Link
EP (1) EP0145510B1 (de)
DE (1) DE3480369D1 (de)
FR (1) FR2551921B1 (de)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3403403A (en) * 1966-03-08 1968-09-24 Army Usa Antenna filter window
US3769623A (en) * 1972-09-21 1973-10-30 Nasa Low loss dichroic plate
FR2349968A1 (fr) * 1976-04-27 1977-11-25 Thomson Csf Guide d'ondes a acces lateral et multiplexeur-demultiplexeur muni d'un tel guide
US4126866A (en) * 1977-05-17 1978-11-21 Ohio State University Research Foundation Space filter surface
US4284992A (en) * 1979-12-26 1981-08-18 Bell Telephone Laboratories, Incorporated Wide scan quasi-optical frequency diplexer
EP0076760A1 (de) * 1981-10-05 1983-04-13 Thomson-Csf Radant Adaptives Mikrowellenraumfilter für eine Antenne mit irgendeiner Polarisation und Verfahren zu seiner Anwendung
FR2518828A1 (fr) * 1981-12-18 1983-06-24 Thomson Csf Filtre spatial de frequences et antenne comportant un tel filtre

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3403403A (en) * 1966-03-08 1968-09-24 Army Usa Antenna filter window
US3769623A (en) * 1972-09-21 1973-10-30 Nasa Low loss dichroic plate
FR2349968A1 (fr) * 1976-04-27 1977-11-25 Thomson Csf Guide d'ondes a acces lateral et multiplexeur-demultiplexeur muni d'un tel guide
US4126866A (en) * 1977-05-17 1978-11-21 Ohio State University Research Foundation Space filter surface
US4284992A (en) * 1979-12-26 1981-08-18 Bell Telephone Laboratories, Incorporated Wide scan quasi-optical frequency diplexer
EP0076760A1 (de) * 1981-10-05 1983-04-13 Thomson-Csf Radant Adaptives Mikrowellenraumfilter für eine Antenne mit irgendeiner Polarisation und Verfahren zu seiner Anwendung
FR2518828A1 (fr) * 1981-12-18 1983-06-24 Thomson Csf Filtre spatial de frequences et antenne comportant un tel filtre

Also Published As

Publication number Publication date
FR2551921B1 (fr) 1986-02-21
FR2551921A1 (fr) 1985-03-15
EP0145510B1 (de) 1989-11-02
DE3480369D1 (en) 1989-12-07

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