EP0378838A1 - Verfahren zur Senkung der Rückstreuung elektromagnetischer Strahlung an einseitig offenen Hohlraumstrukturen - Google Patents

Verfahren zur Senkung der Rückstreuung elektromagnetischer Strahlung an einseitig offenen Hohlraumstrukturen Download PDF

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Publication number
EP0378838A1
EP0378838A1 EP89123645A EP89123645A EP0378838A1 EP 0378838 A1 EP0378838 A1 EP 0378838A1 EP 89123645 A EP89123645 A EP 89123645A EP 89123645 A EP89123645 A EP 89123645A EP 0378838 A1 EP0378838 A1 EP 0378838A1
Authority
EP
European Patent Office
Prior art keywords
electromagnetic radiation
cavity structure
cavity
reduction
cavity structures
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Withdrawn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
EP89123645A
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German (de)
English (en)
French (fr)
Inventor
Joachim Bettermann
Manfred Hochmann
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.)
Airbus Defence and Space GmbH
Original Assignee
Deutsche Aerospace AG
Messerschmitt Bolkow Blohm AG
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 Deutsche Aerospace AG, Messerschmitt Bolkow Blohm AG filed Critical Deutsche Aerospace AG
Publication of EP0378838A1 publication Critical patent/EP0378838A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems

Definitions

  • the invention relates to a method for reducing the backscattering of electromagnetic radiation on cavity structures that are open on one side, such as engine inlets of missiles, aircraft and helicopters. It also relates to a cavity structure that is open on one side.
  • Cavity structures such as the engine inlets of missiles, aircraft or helicopters, caused by multiple reflections of the incident radar energy on the inner walls of the inlets and subsequent reflection at the rear end, for example at the first compressor blade ring, show a high degree of backscattering of the incident radar radiation. This gives for a large aspect angle range and a broad frequency band of the incident electromagnetic radiation. Because of this high Reflection rate, such aircraft can be detected even at a comparatively large distance.
  • the object of the invention is therefore to provide a method by means of which the probability of detection of aircraft equipped with such cavity structures is significantly reduced. Furthermore, the invention is intended to provide a cavity structure which is open on one side and has a significantly reduced radar cross section.
  • the invention solves the problem by a method with the characterizing features of claim 1 and to carry out the method, a cavity structure is formed according to the features of the claim.
  • the method according to the invention leads to a broadband lowering of the radar backscatter cross section of such cavity structures, such as engine inlets, while at the same time requiring little space for any additional structural elements that may be used. Furthermore, the arrangement is characterized by an extremely small restriction of the effective inlet cross-section of the cavity structure while at the same time optimally suppressing the reflection of the incident radar radiation.
  • a largely radar-absorbing design of the inner walls of cavity structures with at least one opening, in particular engine inlets, is therefore provided.
  • These inner walls can be designed as a primary, secondary or non-load-bearing structure.
  • the inner walls of the cavity structure can also be the surfaces of inlet dividers, so-called duct splitters, which are designed according to aerodynamic, structural and / or operational aspects.
  • the cavity structure in the inlet area can be filled with a straight or diagonally arranged mesh which, due to its frequency selectivity, only allows radar energy from certain frequency areas to enter the inlet and reflects radar energy from the other frequency areas.
  • the frequency-dependent absorption profiles of the absorbers on the inner walls in front of and behind the grating are advantageously matched to the reflection characteristics of the grating.
  • the geometric shape of the grille depends on its operationally required filter properties and the aerodynamic and structural boundary conditions.
  • the grid can consist of completely or limited conductive or absorbent material.
  • FIG. 1 The arrangement shown in FIG. 1 is a cross-section through an engine inlet 1, the inlet opening 2 of which is located on the left-hand side of the picture and leads to a first stage (not shown in the figure) of a compressor blade.
  • the inlet opening 2 is inserted in relation to the direction of flow mesh grid 3 which is shown in the left part of Fig. 1 again in plan view.
  • a first absorber 4 is arranged in the form of a thin, approximately 1 millimeter thick layer made of a material that absorbs the electromagnetic radiation.
  • a second absorber 5 is arranged in the area of the greatest curvature of the engine inlet 1 over the entire inner circumference, and finally an inlet divider 6 arranged in the center line of the engine inlet 1 is provided with an absorber layer 7 made of an absorber material.
  • the materials for the three absorbers 4, 5 and 7 mentioned are selected so that their maximum adsorption capacity is in each case at different frequencies of the incident radar radiation, so that due to these mutually offset adsorption profiles, as shown in FIG. 2, in combination with the reflection characteristic of the mesh 3, the broadband suppression of the reflection of the incident radar radiation already described sets.
  • the measures described above are suitable both for newly manufactured engine inlets and for retrofitting existing engines. However, they are not on engine intakes limited, but applicable to all cavity structures on an aircraft that are open on one side and whose radar backscatter cross section is to be reduced.
  • the absorbers 4, 5 and 7 are made of elastomer material, but fiber composite materials or thermoplastics, for example, are also suitable as absorber materials.

Landscapes

  • Radar Systems Or Details Thereof (AREA)
  • Aerials With Secondary Devices (AREA)
  • Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
EP89123645A 1989-01-14 1989-12-21 Verfahren zur Senkung der Rückstreuung elektromagnetischer Strahlung an einseitig offenen Hohlraumstrukturen Withdrawn EP0378838A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3901010 1989-01-14
DE19893901010 DE3901010C1 (enrdf_load_stackoverflow) 1989-01-14 1989-01-14

Publications (1)

Publication Number Publication Date
EP0378838A1 true EP0378838A1 (de) 1990-07-25

Family

ID=6372114

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89123645A Withdrawn EP0378838A1 (de) 1989-01-14 1989-12-21 Verfahren zur Senkung der Rückstreuung elektromagnetischer Strahlung an einseitig offenen Hohlraumstrukturen

Country Status (2)

Country Link
EP (1) EP0378838A1 (enrdf_load_stackoverflow)
DE (1) DE3901010C1 (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2859702A1 (fr) * 1994-07-08 2005-03-18 Aerospatiale Systeme de prise d'air pour aeronef, notamment missile, a conduit double
EP2676099B1 (en) * 2011-02-14 2017-04-26 Leonardo S.P.A. Equipment for the reduction of the radar marking for aircrafts
EP2675712B1 (en) * 2011-02-14 2018-07-04 Leonardo S.P.A. Aircraft with improved aerodynamic performance.
CN111005807A (zh) * 2019-11-22 2020-04-14 北京机电工程研究所 一种应用吸波材料的腔体结构
CN112448110A (zh) * 2020-11-17 2021-03-05 四川天邑康和通信股份有限公司 一种可应用于5g无源das系统的腔体功分器
CN116767497A (zh) * 2023-07-19 2023-09-19 西北工业大学 一种带有人工表面等离激元吸波格栅、方法及进气道

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4007986C1 (en) * 1990-03-13 1991-09-19 Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De Aircraft structure with cavities - filled with material absorbing or reflecting radar vanes for camouflage or imaging
DE4121584A1 (de) * 1991-06-29 1993-01-21 Messerschmitt Boelkow Blohm Verfahren und einrichtung zur radartarnung bei triebwerken
DE4216837C2 (de) * 1992-05-21 1995-11-16 Daimler Benz Aerospace Ag Radartarnung für langsamfliegende rollstabilisierte Flugkörper
DE19528343C2 (de) * 1995-08-02 1997-05-22 Markus Muehleisen Vorrichtung zur reflexionsarmen Absorption von Mikrowellen
DE19807556B3 (de) * 1998-02-23 2013-11-28 Friedrich-Ulf Deisenroth Multispektral signaturreduzierend wirkendes Tarnelement
DE102012023718A1 (de) * 2012-12-05 2014-06-05 Eads Deutschland Gmbh Einlauf für ein Triebwerk eines Luftfahrzeugs
RU2623031C1 (ru) * 2016-06-30 2017-06-21 Публичное акционерное общество "Авиационная холдинговая компания "Сухой" Воздухозаборник самолета

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3509568A (en) * 1968-07-08 1970-04-28 North American Rockwell Inlet attenuator assembly
US4148032A (en) * 1977-10-27 1979-04-03 The United States Of America As Represented By The Secretary Of The Navy Method and means for defocusing engine cavity reflected energy
DE3426990A1 (de) * 1984-07-21 1986-01-30 Messerschmitt-Bölkow-Blohm GmbH, 8012 Ottobrunn Radarschutz an einem fluggeraet
DE3605430A1 (de) * 1986-02-20 1987-08-27 Messerschmitt Boelkow Blohm Einrichtung zur verringerung der radarrueckstrahlung
DE3713875C1 (en) * 1987-04-25 1988-07-07 Messerschmitt Boelkow Blohm Air inlet on aircraft

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3509568A (en) * 1968-07-08 1970-04-28 North American Rockwell Inlet attenuator assembly
US4148032A (en) * 1977-10-27 1979-04-03 The United States Of America As Represented By The Secretary Of The Navy Method and means for defocusing engine cavity reflected energy
DE3426990A1 (de) * 1984-07-21 1986-01-30 Messerschmitt-Bölkow-Blohm GmbH, 8012 Ottobrunn Radarschutz an einem fluggeraet
DE3605430A1 (de) * 1986-02-20 1987-08-27 Messerschmitt Boelkow Blohm Einrichtung zur verringerung der radarrueckstrahlung
DE3713875C1 (en) * 1987-04-25 1988-07-07 Messerschmitt Boelkow Blohm Air inlet on aircraft

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
INTERNATIONAL SYMPOSIUM DIGEST ANTENNAS AND PROPAGATION, Syracuse, 6.-10. Juni 1988, Band 2, Seiten 790-793, IEEE; Hsueh-Jyh Li et al.: "Diaphanization by Absorber Covering" *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2859702A1 (fr) * 1994-07-08 2005-03-18 Aerospatiale Systeme de prise d'air pour aeronef, notamment missile, a conduit double
EP2676099B1 (en) * 2011-02-14 2017-04-26 Leonardo S.P.A. Equipment for the reduction of the radar marking for aircrafts
EP2675712B1 (en) * 2011-02-14 2018-07-04 Leonardo S.P.A. Aircraft with improved aerodynamic performance.
CN111005807A (zh) * 2019-11-22 2020-04-14 北京机电工程研究所 一种应用吸波材料的腔体结构
CN112448110A (zh) * 2020-11-17 2021-03-05 四川天邑康和通信股份有限公司 一种可应用于5g无源das系统的腔体功分器
CN116767497A (zh) * 2023-07-19 2023-09-19 西北工业大学 一种带有人工表面等离激元吸波格栅、方法及进气道

Also Published As

Publication number Publication date
DE3901010C1 (enrdf_load_stackoverflow) 1990-08-23

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