EP0669674B1 - Device for camouflaging antennas - Google Patents
Device for camouflaging antennas Download PDFInfo
- Publication number
- EP0669674B1 EP0669674B1 EP94119638A EP94119638A EP0669674B1 EP 0669674 B1 EP0669674 B1 EP 0669674B1 EP 94119638 A EP94119638 A EP 94119638A EP 94119638 A EP94119638 A EP 94119638A EP 0669674 B1 EP0669674 B1 EP 0669674B1
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- EP
- European Patent Office
- Prior art keywords
- layer
- antenna
- polarisator
- microwaves
- layers
- 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.)
- Expired - Lifetime
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- 239000006096 absorbing agent Substances 0.000 claims description 5
- 238000010521 absorption reaction Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- 229910000859 α-Fe Inorganic materials 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 2
- 239000002223 garnet Substances 0.000 claims description 2
- 230000009466 transformation Effects 0.000 claims description 2
- 230000010287 polarization Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- BGPVFRJUHWVFKM-UHFFFAOYSA-N N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] Chemical compound N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] BGPVFRJUHWVFKM-UHFFFAOYSA-N 0.000 description 2
- 239000006117 anti-reflective coating Substances 0.000 description 2
- TVEXGJYMHHTVKP-UHFFFAOYSA-N 6-oxabicyclo[3.2.1]oct-3-en-7-one Chemical compound C1C2C(=O)OC1C=CC2 TVEXGJYMHHTVKP-UHFFFAOYSA-N 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002044 microwave spectrum Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 230000003319 supportive effect Effects 0.000 description 1
Images
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
- H01Q17/007—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems with means for controlling the absorption
-
- 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
- H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
-
- 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
- H01Q15/148—Reflecting surfaces; Equivalent structures with means for varying the reflecting properties
-
- 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
- H01Q15/22—Reflecting surfaces; Equivalent structures functioning also as polarisation filter
Definitions
- the present invention relates to a device for Antennae camouflaged against microwaves.
- Camouflage When camouflaging against radar of military equipment Antennas pose a particular problem.
- the conventional one Camouflage is using very narrow band frequency-selective layers only the useful signal frequency of the radio system belonging to the antenna reach the detector let, however, deflect all other frequencies and / or to absorb.
- the main reflector a parabolic antenna made from a broadband radar absorber be built, the outer surface of which on the Radio frequency-tuned frequency-selective reflective tape owns.
- the radome in frequency-selective manner, i.e. only for them Usable frequency transparent and for other frequencies be reflective.
- the present invention has for its object a Device for camouflaging antennas against the location by To create microwaves that have a significantly better camouflage enables, especially against impinging microwaves, whose frequencies differ only slightly from the frequencies distinguish the useful waves of the antenna.
- the Device from an electromagnetic non-reciprocal Component exists in the direction of incidence of the microwaves seen in front of the antenna.
- the non-reciprocal Component in the form of a distance in front of the Antenna arranged radome and contains one magneto-optical layer surrounded by a ring magnet and on both sides of one Polarizer layer is covered, which is a high Transparency for a given linear polarization direction have and a high absorption for the perpendicular Have directions of polarization, the two Polarization layers rotated by 45 ° to each other are arranged.
- the magneto-optical layer is advantageously a so-called Faraday lathe operator who enforces them electromagnetic, linearly polarized waves by 45 ° twisted and which consists of a ferrite and / or garnet.
- the polarizer layers advantageously consist of thin strips arranged parallel to one another Absorber.
- Each polarizer layer can be on the Faraday rotator facing surface with a quarter wavelength layer from a uniaxial anisotropic material for transformation circularly polarized waves into linearly polarized waves be provided.
- the magneto-optical layer directly on the incident microwave surface of the antenna is applied and when the two by 45 ° to each other twisted polarizer layers on the one hand Radomapertur and on the other on the subreflector or Exciter or detector are arranged.
- Electromagnetic by the use according to the invention The advantage of non-reciprocal layers is achieved that Radio signals in the range of the useful frequency to a certain one Time either only get from the outside to the antenna or can be radiated outwards from the antenna. Radio signals of different frequencies can be used in a known manner be distracted and / or absorbed, here too again frequency selective layers and broadband Radar absorbers can also be supportive.
- a detection by an opposing radar system which points to operates at almost the same frequency as the one to be camouflaged Antenna, is therefore quite well with conventional camouflage possible, but not when using the invention Contraption.
- Another advantage is that the Selectivity of a frequency selective layer for supplementary external frequency camouflage lower requirements subject to; it can affect the range of effectiveness of the non-reciprocal layer are weakened; at sufficient effective range of non-reciprocal Shift may not need to be supplemented by conventional camouflage measures.
- non-reciprocal appearances are here preferably understood magneto-optical effects on the reciprocity law formulated by Helmholtz for electromagnetic waves are based and which presuppose that there is an additional magnetic field (Bergmann / Schaefer “Textbook of Experimental Physics", volume III Optik (Walter de Gruyter-Verlag, Berlin). Other non-reciprocal Effects may also be useful.
- Fig. 1 denotes an antenna which has a Line 2 with a radio system, not shown connected is.
- 3 the level is in the radomaperture referred to, with an inventive according to this level Device for camouflaging the antenna 1 against the location is arranged by opposing microwaves.
- the Device consists of an electromagnetic non-reciprocal Component that is a non-reciprocal layer 4 has, which is arranged in level 3 of the Radomapertur is.
- the non-reciprocal layer 4 is of one Ring magnet 5 surrounding the necessary magnetic field in the aperture creates. It can be both electrical and Permanent magnets are used. Offer electromagnets the benefit of switching between Transparent states of the component.
- suitable Shaping can be a homogeneous field in the non-reciprocal field Layer 4 of the component can be achieved.
- a variation of the magnetic field over the Aperture may increase the effective Bandwidth can be exploited or prevented at opposite the aperture has a smaller cross-sectional area of the antenna Effectiveness reduction of the camouflage, since on the edge of Aperture penetrating waves of the locating radar not on the Hit the antenna and therefore not be reflected.
- the non-reciprocal layer 4 As material for the non-reciprocal layer 4, which under the influence of the magnetic field caused by the Ring magnet 5 is generated, the polarization plane twisted electromagnetic linearly polarized waves, a so-called Faraday lathe comes from ferrites and / or Grenades in question, as they are used in HF technology Directional lines are used. Layer 4 is designed for a 45 ° rotation for frequencies in here area of interest.
- this non-reciprocal layer There is 4 on both sides of this non-reciprocal layer a polarizer layer 6, 7 applied, each one high transparency for a given direction of polarization and a high absorption for the perpendicular Have direction of polarization.
- the two Polarizer layers 6, 7 are at 45 ° to each other twisted arranged.
- With 8 is also a holder for the ring magnet, the non-reciprocal layer and the called two polarizer layers.
- an electromagnet determines the direction of the applied magnetic field (inside or outside directed) the transparency state of the radome, i.e. the Send or receive transparency.
- the polarizer layers 6, 7 can advantageously be made of thin strips of an absorber arranged in parallel be built up, with the field shares parallel to the Stripes are absorbed, but perpendicular to them be transmitted.
- the antenna is also to transmit, the Direction of transparency are reversed, for which the cause of the the non-reciprocal effects (at magneto-optical effect the applied magnetic field) reversed Need to become.
- the electromagnetic wave of the locating radar not the radome penetrate.
- suitable anti-reflective coatings the radome as they are known from optics, penetrates the Wave into the radome and is absorbed there.
- the camouflaged antenna can transmit their signals with only a small amount Send out damping.
- Anti-reflective coatings on the radome are except for that Absorption of incident waves in the state of Transmission transparency also useful for increasing the Radome transparency for the transmitted ones Useful signals, as well as the reflection reduction in the state of Reception transparency.
- the antenna to be camouflaged is one Mirror antenna, e.g. a parabolic antenna 11, as in Fig. 2 is shown, so instead of the radome or in Combination with it part of the antenna itself is non-reciprocal be carried out.
- the non-reciprocal Layer 14 i.e. the Faraday lathe, in the form the antenna surface 19 applied to this.
- the two polarizer layers 16, 17 rotated relative to one another by 45 ° can in this case on the one hand on the Radomapertur whose Level in Fig. 2 is designated 13, and on the other the subreflector or exciter and / or detector 20 to be ordered.
- At 18 there is one again Bracket for the Radomapertur, with 15 a the non-reciprocal Layer surrounding ring magnet and with 12 one Connection to a radio system called.
- the useful signal remains with the device according to the invention the antenna to be camouflaged practically undisturbed when it is linearly polarized, the orientation of the Polarization layers 6, 7; 16, 17 and antenna 1 or 11 matched to the desired direction of polarization must become.
- the antenna 1 to be camouflaged circularly polarized waves receive or send, this can be done in that additionally on the two, facing away from the Faraday lathe 4 Outside of the polarizer layers 6, 7 one each so-called quarter-wave layer 9, 10 from uniaxial anisotropic material is applied.
- the additional layers 9, 10 transform circularly polarized waves into linear polarized waves and vice versa.
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Aerials With Secondary Devices (AREA)
- Radar Systems Or Details Thereof (AREA)
Description
Die vorliegende Erfindung betrifft eine Vorrichtung zur Tarnung von Antennen gegen die Ortung durch Mikrowellen.The present invention relates to a device for Antennae camouflaged against microwaves.
Bei der Tarnung gegen Radar militärischer Geräte stellen Antennen ein besonderes Problem dar. Die herkömmliche Tarnung besteht darin, unter Ausnutzung sehr schmalbandiger frequenzselektiver Schichten nur die Nutzsignalfrequenz des zur Antenne gehörenden Funksystems zum Detektor gelangen zu lassen, alle anderen Frequenzen jedoch abzulenken und/oder zu absorbieren. Beispielsweise kann der Hauptreflektor einer Parabolantenne aus einem breitbandigen Radarabsorber aufgebaut werden, dessen Außenfläche eine auf die Funkfrequenz abgestimmte frequenzselektive Reflexionsfolie besitzt. Alternativ kann auch das Radom in frequenzselektiver Weise aufgebaut werden, d.h. nur für die Nutzfrequenz transparent und für andere Frequenzen reflektierend sein.When camouflaging against radar of military equipment Antennas pose a particular problem. The conventional one Camouflage is using very narrow band frequency-selective layers only the useful signal frequency of the radio system belonging to the antenna reach the detector let, however, deflect all other frequencies and / or to absorb. For example, the main reflector a parabolic antenna made from a broadband radar absorber be built, the outer surface of which on the Radio frequency-tuned frequency-selective reflective tape owns. Alternatively, the radome in frequency-selective manner, i.e. only for them Usable frequency transparent and for other frequencies be reflective.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine Vorrichtung zur Tarnung von Antennen gegen die Ortung durch Mikrowellen zu schaffen, die eine erheblich bessere Tarnung ermöglicht, insbesondere gegen auftreffende Mikrowellen, deren Frequenzen sich nur geringfügig von den Frequenzen der Nutzwellen der Antenne unterscheiden. The present invention has for its object a Device for camouflaging antennas against the location by To create microwaves that have a significantly better camouflage enables, especially against impinging microwaves, whose frequencies differ only slightly from the frequencies distinguish the useful waves of the antenna.
Zur Lösung dieser Aufgabe wird vorgeschlagen, daß die Vorrichtung aus einem elektromagnetisch nicht-reziproken Bauelement besteht, das in Einfallsrichtung der Mikrowellen gesehen vor der Antenne angeordnet wird.To solve this problem it is proposed that the Device from an electromagnetic non-reciprocal Component exists in the direction of incidence of the microwaves seen in front of the antenna.
Bei einem bevorzugten Ausführungsbeispiel weist das nicht-reziproke Bauelement die Form eines im Abstand vor der Antenne angeordneten Radoms auf und enthält eine magnetooptische Schicht, die von einem Ringmagneten umgeben ist und die auf beiden Seiten von je einer Polarisatorschicht bedeckt ist, welche eine hohe Transparenz für eine gegebene lineare Polarisationsrichtung aufweisen und eine hohe Absorption für die dazu senkrechten Polarisationsrichtungen aufweisen, wobei die beiden Polarisationsschichten um 45° zueinander verdreht angeordnet sind.In a preferred embodiment, the non-reciprocal Component in the form of a distance in front of the Antenna arranged radome and contains one magneto-optical layer surrounded by a ring magnet and on both sides of one Polarizer layer is covered, which is a high Transparency for a given linear polarization direction have and a high absorption for the perpendicular Have directions of polarization, the two Polarization layers rotated by 45 ° to each other are arranged.
Vorteilhafterweise ist die magnetooptische Schicht ein sogenannter Faraday-Dreher, der die sie durchsetzenden elektromagnetischen, linear polarisierten Wellen um 45° verdreht und der aus einem Ferrit und/oder Granat besteht.The magneto-optical layer is advantageously a so-called Faraday lathe operator who enforces them electromagnetic, linearly polarized waves by 45 ° twisted and which consists of a ferrite and / or garnet.
Die Polarisatorschichten bestehen vorteilhafterweise aus parallel zueinander angeordneten dünnen Streifen eines Absorbers.The polarizer layers advantageously consist of thin strips arranged parallel to one another Absorber.
Jede Polarisatorschicht kann auf der dem Faraday-Dreher abgewandten Oberfläche mit einer Viertelwellenlängenschicht aus einem einachsig anisotropen Material zur Transformation zirkular polarisierter Wellen in linear polarisierte Wellen versehen sein.Each polarizer layer can be on the Faraday rotator facing surface with a quarter wavelength layer from a uniaxial anisotropic material for transformation circularly polarized waves into linearly polarized waves be provided.
Im Falle von Parabolantennen ist es besonders vorteilhaft, wenn die magnetooptische Schicht direkt auf der den einfallenden Mikrowellen zugewandten Oberfläche der Antenne aufgebracht ist und wenn die beiden um 45° zueinander verdrehten Polarisatorschichten zum einen auf einer Radomapertur und zum anderen auf dem Subreflektor bzw. Erreger oder Detektor angeordnet sind.In the case of parabolic antennas, it is particularly advantageous if the magneto-optical layer directly on the incident microwave surface of the antenna is applied and when the two by 45 ° to each other twisted polarizer layers on the one hand Radomapertur and on the other on the subreflector or Exciter or detector are arranged.
Durch die erfindungsgemäße Verwendung elektromagnetisch nicht-reziproker Schichten wird der Vorteil erzielt, daß Funksignale im Bereich der Nutzfrequenz zu einer bestimmten Zeit nur entweder von außen bis zur Antenne vordringen oder von der Antenne nach außen abgestrahlt werden können. Funksignale abweichender Frequenz können in bekannter Weise abgelenkt und/oder absorbiert werden, wobei auch hier wieder frequenzselektive Schichten und breitbandige Radarabsorber zusätzlich unterstützend sein können.Electromagnetic by the use according to the invention The advantage of non-reciprocal layers is achieved that Radio signals in the range of the useful frequency to a certain one Time either only get from the outside to the antenna or can be radiated outwards from the antenna. Radio signals of different frequencies can be used in a known manner be distracted and / or absorbed, here too again frequency selective layers and broadband Radar absorbers can also be supportive.
Gegenüber der konventionellen Tarnung mittels frequenzselektiver Schichten wird auch die Rückstreuung im Bereich der Nutzfrequenz unterbunden. Dies ist besonders vorteilhaft, da sich die Arbeitsfrequenzen der Radarsysteme um typische Frequenzstellen im Mikrowellenspektrum gruppieren.Compared to conventional camouflage using frequency-selective layers, the backscatter in the Range of the useful frequency prevented. This is special advantageous because the working frequencies of the radar systems around typical frequency points in the microwave spectrum group.
Ein Ortung durch ein gegnerisches Radarsystem, welches auf der nahezu gleichen Frequenz arbeitet, wie die zu tarnende Antenne, ist somit bei konventioneller Tarnung durchaus möglich, nicht jedoch bei Anwendung der erfindungsgemäßen Vorrichtung.A detection by an opposing radar system, which points to operates at almost the same frequency as the one to be camouflaged Antenna, is therefore quite well with conventional camouflage possible, but not when using the invention Contraption.
Ein weiterer Vorteil ist darin zu sehen, daß die Trennschärfe einer frequenzselektiven Schicht zur ergänzenden Fremdfrequenz-Tarnung geringeren Anforderungen unterliegt; sie kann auf die Bandbreite der Wirksamkeit der nicht-reziproken Schicht abgeschwächt werden; bei ausreichender wirksamer Bandbreite der nicht-reziproken Schicht erübrigt sich gegebenenfalls die Ergänzung durch konventionelle Tarnmaßnahmen.Another advantage is that the Selectivity of a frequency selective layer for supplementary external frequency camouflage lower requirements subject to; it can affect the range of effectiveness of the non-reciprocal layer are weakened; at sufficient effective range of non-reciprocal Shift may not need to be supplemented by conventional camouflage measures.
Unter nicht-reziproken Erscheinungen werden hier vorzugsweise magnetooptische Effekte verstanden, die auf dem von Helmholtz formulierten Reziprozitätsgesetz für elektromagnetische Wellen beruhen und die voraussetzen, daß ein zusätzliches Magnetfeld vorhanden ist (Bergmann/Schaefer "Lehrbuch der Experimentalphysik", Band III Optik (Walter de Gruyter-Verlag, Berlin). Andere nicht-reziproke Effekte könnten eventuell auch nützlich sein.Among non-reciprocal appearances are here preferably understood magneto-optical effects on the reciprocity law formulated by Helmholtz for electromagnetic waves are based and which presuppose that there is an additional magnetic field (Bergmann / Schaefer "Textbook of Experimental Physics", volume III Optik (Walter de Gruyter-Verlag, Berlin). Other non-reciprocal Effects may also be useful.
Eine bekannte Anwendung des nicht-reziproken Effektes im Zusammenhang mit Spiegel für Ringlaser ist beispielsweise in der deutschen Patentanmeldung P 32 33 035 beschrieben.A known application of the non-reciprocal effect in Connection with mirror for ring laser is for example described in German patent application P 32 33 035.
Im folgenden wird die Erfindung anhand der Zeichnung näher erläutert, in der vorteilhafte Ausführungsbeispiele dargestellt sind. Es zeigen:
- Fig. 1
- einen Schnitt durch ein erstes Ausführungsbeispiel und
- Fig. 2
- einen Schnitt durch ein zweites Ausführungsbeispiel.
- Fig. 1
- a section through a first embodiment and
- Fig. 2
- a section through a second embodiment.
In Fig. 1 ist mit 1 eine Antenne bezeichnet, die über eine
Leitung 2 mit einem nicht dargestellten Funksystem
verbunden ist. Mit 3 ist die Ebene in der Radomapertur
bezeichnet, wobei in dieser Ebene eine erfindungsgemäße
Vorrichtung zur Tarnung der Antenne 1 gegen die Ortung
durch gegnerische Mikrowellen angeordnet ist. Die
Vorrichtung besteht aus einem elektromagnetisch nicht-reziproken
Bauelement, das eine nicht-reziproke Schicht 4
aufweist, die in der Ebene 3 der Radomapertur angeordnet
ist. Die nicht-reziproke Schicht 4 ist von einem
Ringmagneten 5 umgeben, der das notwendige Magnetfeld in
der Apertur erzeugt. Es können sowohl Elektro- als auch
Permanentmagnete verwendet werden. Elektromagnete bieten
den Vorteil eines Umschaltens zwischen den
Transparenzzuständen des Bauelementes. Durch geeignete
Formgebung kann ein homoges Feld im Bereich der nicht-reziproken
Schicht 4 des Bauelementes erzielt werden.
Andererseits kann eine Variation des Magnetfeldes über der
Apertur gegebenenfalls zu einer Erhöhung der wirksamen
Bandbreite ausgenutzt werden oder verhindert bei gegenüber
der Apertur kleineren Querschnittsfläche der Antenne eine
Wirksamkeitsreduzierung der Tarnung, da am Rande der
Apertur eindringende Wellen des Ortungsradars nicht auf die
Antenne treffen und somit nicht reflektiert werden.In Fig. 1, 1 denotes an antenna which has a
Als Material für die nicht-reziproke Schicht 4, welches
unter dem Einfluß des Magnetfeldes, das durch den
Ringmagneten 5 erzeugt wird, die Polarisationsebene
elektromagnetischer linear polarisierter Wellen verdreht,
kommt ein sogenannter Faraday-Dreher aus Ferriten und/oder
Granaten in Frage, wie sie in der HF-Technik auch für
Richtungsleitungen verwendet werden. Die Schicht 4 ist
ausgelegt für eine Drehung um 45° für Frequenzen im hier
interessierenden Bereich.As material for the
Auf beiden Seiten dieser nicht-reziproken Schicht 4 ist
eine Polarisatorschicht 6, 7 aufgebracht, die jeweils eine
hohe Transparenz für eine vorgegebene Polarisationsrichtung
und eine hohe Absorption für die dazu senkrechte
Polarisationsrichtung aufweisen. Die beiden
Polarisatorschichten 6, 7 sind um 45° gegeneinander
verdreht angeordnet. Mit 8 ist ferner eine Halterung für
den Ringmagneten, die nicht-reziproke Schicht und die
beiden Polarisatorschichten bezeichnet. There is 4 on both sides of this non-reciprocal layer
a
Im Falle eines Elektromagneten bestimmt die Richtung des angelegten Magnetfeldes (nach innen oder nach außen gerichtet) den Transparenzzustand des Radoms, d.h. die Sende- oder Empfangstransparenz.In the case of an electromagnet determines the direction of the applied magnetic field (inside or outside directed) the transparency state of the radome, i.e. the Send or receive transparency.
Die Polarisatorschichten 6, 7 können vorteilhafterweise aus
parallel angeordneten dünnen Streifen eines Absorbers
aufgebaut werden, wobei die Feldanteile parallel zu den
Streifen absorbiert werden, solche senkrecht dazu hingegen
transmittiert werden.The
Wie aus der Beschreibung dieses Ausführungsbeispiels deutlich geworden ist, führt die Verwendung nicht-reziproker Effekte zum Zwecke der Tarnung der Antenne dazu, daß die Rückstreuung der zur Ortung eingesetzten gegnerischen elektromagnetischen Wellen weitgehend vermieden wird. Bei ungetarnten Antennen kann der Rückstreuquerschnitt sehr große Werte annehmen und so die an anderen Stellen angewandten Tarnmaßnahmen zunichte machen. Wenn jedoch die Transmission des Radoms in der Empfangsrichtung sehr hohe Werte und in der Senderichtung sehr niedrige Werte annimmt, so kann die einfallende Welle des Ortungsradars zwar zur Antenne vordringen, nicht jedoch wieder austreten, um so dem Ortungsradar ein Echo zu liefern. Andererseits kann die so getarnte Antenne einfallende Signale mit nur geringer Dämpfung empfangen.As from the description of this embodiment has become clear, the use of non-reciprocal leads Effects for the purpose of camouflaging the antenna that the backscatter used for the location opposing electromagnetic waves largely is avoided. With camouflaged antennas, the Backscatter cross section take very large values and so the camouflage measures applied elsewhere do. However, if the transmission of the radome in the Direction of reception very high values and in the direction of transmission assumes very low values, so the incident wave of the radar find their way to the antenna, but not exit again in order to echo the location radar deliver. On the other hand, the antenna so camouflaged receive incoming signals with little attenuation.
Soll die Antenne auch senden, so muß die Transparenzrichtung umgekehrt werden, wofür die Ursache der die nicht-reziproken Effekte hervorrufenden Maßnahmen (beim magnetooptischen Effekt das angelegte Magnetfeld) umgekehrt werden müssen. In diesem Zustand kann die elektromagnetische Welle des Ortungsradars das Radom nicht durchdringen. Bei geeigneten Entspiegelungsschichten auf dem Radom, wie sie aus der Optik bekannt sind, dringt die Welle in das Radom ein und wird dort absorbiert. Die getarnte Antenne kann dagegen ihre Signale mit nur geringer Dämpfung aussenden.If the antenna is also to transmit, the Direction of transparency are reversed, for which the cause of the the non-reciprocal effects (at magneto-optical effect the applied magnetic field) reversed Need to become. In this state, the electromagnetic wave of the locating radar not the radome penetrate. With suitable anti-reflective coatings the radome, as they are known from optics, penetrates the Wave into the radome and is absorbed there. The camouflaged antenna, on the other hand, can transmit their signals with only a small amount Send out damping.
Soll eine Bordradar-Antenne auf diese Weise getarnt werden, so muß in den relativ kurzen Sendephasen das Radom auf "Sendetransparenz" und in der übrigen Zeit auf "Empfangstransparenz" geschaltet werden.If a radar antenna is to be camouflaged in this way, the radome must open in the relatively short transmission phases "Send Transparency" and the rest of the time "Receive transparency" can be switched.
Entspiegelungsschichten auf dem Radom sind außer für die Absorption einfallender Wellen im Zustand der Sendetransparenz auch nützlich für die Erhöhung der Radomtransparenz für die jeweils durchgelassenen Nutzsignale, sowie die Reflexionsminderung im Zustand der Empfangstransparenz.Anti-reflective coatings on the radome are except for that Absorption of incident waves in the state of Transmission transparency also useful for increasing the Radome transparency for the transmitted ones Useful signals, as well as the reflection reduction in the state of Reception transparency.
Handelt es sich bei der zu tarnenden Antenne um eine
Spiegelantenne, z.B. eine Parabolantenne 11, wie sie in
Fig. 2 dargestellt ist, so kann anstelle des Radoms oder in
Kombination mit ihm ein Teil der Antenne selbst nicht-reziprok
ausgeführt werden. Zu diesem Zweck wird die nicht-reziproke
Schicht 14, d.h. der Faraday-Dreher, in der Form
der Antennenoberfläche 19 auf diese aufgebracht. Die beiden
um 45° zueinander verdrehten Polarisatorschichten 16, 17
können in diesem Fall zum einen auf der Radomapertur, deren
Ebene in Fig. 2 mit 13 bezeichnet ist, und zum anderen auf
dem Subreflektor bzw. Erreger und/oder Detektor 20
angeordnet werden. Mit 18 ist auch hier wieder eine
Halterung für die Radomapertur, mit 15 ein die nicht-reziproke
Schicht umgebender Ringmagnet und mit 12 eine
Verbindung zu einem Funksystem bezeichnet.If the antenna to be camouflaged is one
Mirror antenna, e.g. a
Mit der erfindungsgemäßen Vorrichtung bleibt das Nutzsignal
der zu tarnenden Antenne praktisch ungestört, wenn es
linear polarisiert ist, wobei die Orientierung der
Polarisationsschichten 6, 7; 16, 17 und der Antenne 1 bzw.
11 auf die gewünschte Polarisationsrichtung abgestimmt
werden muß.The useful signal remains with the device according to the invention
the antenna to be camouflaged practically undisturbed when it
is linearly polarized, the orientation of the
Soll bei dem in Fig. 1 dargestellten Ausführungsbeispiel
die zu tarnende Antenne 1 zirkular polarisierte Wellen
empfangen oder senden, so kann dies dadurch erfolgen, daß
zusätzlich auf den beiden, dem Faraday-Dreher 4 abgewandten
Außenseiten der Polarisatorschichten 6, 7 je eine
sogenannte Viertelwellenlängenschicht 9, 10 aus einachsig
anisotropem Material aufgebracht wird. Die Zusatzschichten
9, 10 transformieren zirkular polarisierte Wellen in linear
polarisierte Wellen und umgekehrt.Should in the embodiment shown in Fig. 1
the
Claims (6)
- Device for camouflaging antennae from detection by microwaves, in particular by microwaves of frequencies which differ only slightly from the frequencies of operational waves of antennae to be camouflaged, characterised in that it is composed of an electro-magnetically non-reciprocal assembly element arranged in front of the antenna, as seen in the direction of incidence of the microwaves, and comprises polarisator layers which are turned by 45° toward each other.
- Device according to Claim 1, characterised in that the non-reciprocal assembly element has the shape of a radome arranged at a distance in front of the antenna and contains a magneto-optical layer (4) which is encapsulated by a circular magnet (5) and on both sides covered by a respective polarisator layer (6, 7) of high transparency for a given linear polarisation direction and high absorption for a thereto vertical polarisation direction, and both polarisator layers (6, 7) are turned by 45° towards to each other.
- Device according to Claims 1 and 2, characterised in that the magneto-optical layer is a so-called Faraday rotor which rotates the electromagnetic linearly polarised waves which pass through it by 45° and that it is made of a ferrite and/or garnet.
- Device according to one of Claims 1 to 3, characterised in that the polarisator layer (6, 7) are composed of parallel thin stripes of an absorber.
- Device according to Claims 1 to 4, characterised in that each polarisator layer (6, 7) is on the surface facing away from the Faraday rotor (4) provided with a quarterwave longitudinal layer (9, 10) of a uni-axial anisotrope material for transformation of circularly polarised waves into linearly polarised waves.
- Device according to Claim 1, characterised in that in the event of parabola antennae the magneto-optical layer (14) is applied directly onto the surface (19) of the antenna (11) facing towards incidental microwaves, and both polarisator layers (16, 17), which are turned by 45° towards to each other, are arranged, on the one hand, on the radome aperture and, on the other hand, on the subreflector or exciter or detector (20).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4405996A DE4405996C2 (en) | 1994-02-24 | 1994-02-24 | Antenna camouflage device |
| DE4405996 | 1994-02-24 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0669674A1 EP0669674A1 (en) | 1995-08-30 |
| EP0669674B1 true EP0669674B1 (en) | 1999-02-24 |
Family
ID=6511109
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP94119638A Expired - Lifetime EP0669674B1 (en) | 1994-02-24 | 1994-12-13 | Device for camouflaging antennas |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0669674B1 (en) |
| DE (2) | DE4405996C2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3003700B1 (en) * | 2013-03-19 | 2016-07-22 | Thales Sa | ANTENNA RADAR SIGNATURE REDUCTION DEVICE AND ASSOCIATED ANTENNA SYSTEM |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3309704A (en) * | 1965-09-07 | 1967-03-14 | North American Aviation Inc | Tunable absorber |
| GB1416343A (en) * | 1972-02-16 | 1975-12-03 | Secr Defence | Radomes |
| DE3222035A1 (en) * | 1981-06-13 | 1983-03-24 | Teldix Gmbh, 6900 Heidelberg | Laser rotational speed measuring device |
| US5034750A (en) * | 1983-10-31 | 1991-07-23 | Raytheon Company | Pulse radar and components therefor |
| GB8905904D0 (en) * | 1989-03-15 | 1989-04-26 | Cambridge Computer | Improvements in antenna polarizers |
| DE3920110A1 (en) * | 1989-06-20 | 1991-02-07 | Dornier Luftfahrt | Radome or radar absorber with adjustable transparency - has photosensitive layer with inside light source controlling EM state from reflection to transparency |
| SE505054C2 (en) * | 1992-04-30 | 1997-06-16 | Celsiustech Electronics Ab | Screen device and radome including screen device |
| US5278562A (en) * | 1992-08-07 | 1994-01-11 | Hughes Missile Systems Company | Method and apparatus using photoresistive materials as switchable EMI barriers and shielding |
-
1994
- 1994-02-24 DE DE4405996A patent/DE4405996C2/en not_active Expired - Fee Related
- 1994-12-13 EP EP94119638A patent/EP0669674B1/en not_active Expired - Lifetime
- 1994-12-13 DE DE59407846T patent/DE59407846D1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE59407846D1 (en) | 1999-04-01 |
| EP0669674A1 (en) | 1995-08-30 |
| DE4405996C2 (en) | 1996-01-11 |
| DE4405996A1 (en) | 1995-08-31 |
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