EP0170726A1 - Dual reflector directional antenna - Google Patents

Dual reflector directional antenna Download PDF

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Publication number
EP0170726A1
EP0170726A1 EP84115744A EP84115744A EP0170726A1 EP 0170726 A1 EP0170726 A1 EP 0170726A1 EP 84115744 A EP84115744 A EP 84115744A EP 84115744 A EP84115744 A EP 84115744A EP 0170726 A1 EP0170726 A1 EP 0170726A1
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EP
European Patent Office
Prior art keywords
directional antenna
foam body
antenna according
reflector
antenna
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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.)
Ceased
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EP84115744A
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German (de)
French (fr)
Inventor
Eberhard Dipl.-Ing. Tauschek
Karl-Peter Ing. Gessner
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Siemens AG
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Siemens AG
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Publication of EP0170726A1 publication Critical patent/EP0170726A1/en
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    • 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
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/40—Radiating elements coated with or embedded in protective material

Definitions

  • the invention relates to an externally closed two-directional directional antenna (Cassegrain antenna, Gregory antenna) with a main reflector having the shape of a paraboloid of revolution, a catch reflector and an exciter horn antenna that is passed through a central opening of the main reflector.
  • an externally closed two-directional directional antenna (Cassegrain antenna, Gregory antenna) with a main reflector having the shape of a paraboloid of revolution, a catch reflector and an exciter horn antenna that is passed through a central opening of the main reflector.
  • Parabolic mirror antennas are increasingly being used for directional radio connections in the frequency bands P, K, R, in which small mirror diameters of 0.4 m to 1.2 m are usually sufficient.
  • the introduction of TV satellites brings a need for X-band mirror antennas with a mirror diameter of 0.9 - 1.2 m.
  • Most applications of such mirror antennas require either dual linear polarization or e.g. in the TV application left / right circular polarization with good electrical specification values.
  • Microwave antennas with so-called high performance behavior usually consist of three main units in their mechanical design.
  • the first unit is the main reflector, which is a section of a paraboloid of revolution and can be corrected in some cases.
  • the second unit is the excitation unit, which can be integrated with an auxiliary mirror.
  • the third main unit consists of a radome with an absorber collar, screens, supports for the exciter, compressed air seal, etc. These three Main units have to be assembled to each other in a complex manner using precise mechanical designs.
  • special protective measures are required, since such directional antennas usually have to be designed for all-weather use on towers.
  • the object of the invention is to show a new technology for the construction of relatively small two-directional directional antennas with high performance behavior, which guarantees high precision at relatively low manufacturing costs, which are easy to maintain, particularly in the TV application, even in large series can.
  • this object is achieved in that the metallic reflector surfaces on a surrounded by a compacted skin and its outer shape to the contour of the main reflector and the contour of the catch reflector are matched plastic foam body which has a shape in the region of the central opening of the main reflector for receiving the exciter horn.
  • the foam body is made of polyurethane, for example. Rigid foam. Such a body can be produced in a preferably selectively heatable form by the integral foam process.
  • the reflector surfaces can be metallized using a suitable process and fixed using protective layers.
  • the exciter horn radiator which can also be designed as an open circular waveguide, can be screwed into a molded holder.
  • the exciter horn radiator with its flange can also be removed by metallization form the speaking structure of the foam body.
  • preformed metal surfaces are also possible as inserts for the implementation of the two reflectors.
  • the plastic foam body advantageously has no densified skin in the area of the aperture of the exciter horn.
  • the directional antenna according to the invention forms a very stable unit.
  • the manufacturing process provides an exact assignment of the reflector excitation system that corresponds to the quality of the shape.
  • the figure shows in a sectional side view a section of a two-reflector directional antenna which is constructed according to the Cassegrain principle.
  • This antenna consists of a foam body 4, for example made of rigid polyurethane foam, which is enclosed by a compressed skin 3, which has the contour of a parabolic reflector cutout for attaching a correspondingly shaped main reflector 1 and the contour of a catch reflector 2 and forms additional functional units.
  • the foam body 4 can be produced by the integral foam process in a preferably selectively heatable form.
  • the reflector surfaces 1 and 2 are formed by a metallization layer and are fixed by protective layers.
  • An exciter horn 7 is inserted into a shape 6, which is designed as a holder, with which the exciter horn 7, which has a screw flange 9, is screwed as an insert.
  • the shape 6 for receiving the exciter horn 7 lies in the area of a central opening 5 of the main reflector 1.
  • the plastic foam body 4 has no compacted skin.
  • areas 10 of the foam body 4 are designed pyramid-shaped and also by metallization in the figure Aperture-like structures 11 shown in broken lines are provided, so that a targeted improvement in the secondary and retroreflective behavior of the antenna can be achieved.
  • reinforcements 14 for the assembly and in the extension of the molding 6 to the rear are foamed housing parts 15, which can serve as a space for accommodating a polarization switch, electronic assemblies and assembly parts.
  • the skin 3 in the exemplary embodiment consists of an approximately 0.5-1 mm thick non-porous layer which, in a region of approximately 7 mm, merges into the foam of uniform density of approximately 40 kg / m 3 .
  • Reinforcements for mast assembly or the like can be provided by inserting parts into the foaming device.
  • the antenna according to the invention forms a dense unit, which is broken only on its rear side by a feed waveguide 17 and possibly on the front side by a balancing device which acts in the apex of the catch reflector 2.
  • the space between the main reflector 1, the subreflector 2 and the excitation horn antenna 7 filled with air in the exemplary embodiment of the invention has a tg ⁇ of approximately 0.0001 to 0.001 with a dielectric constant ⁇ r of 1.04 due to the foam to 1.25.
  • values of ⁇ 1.04 and tg ⁇ ⁇ 0.0001 apply.
  • the medium of the foam body 4 steadily condenses to the skin 3. Any changes in the amplitudes / phase conditions compared to an imaginary directional antenna filled with air can be compensated for by corrections to the main reflector 1 or the catch reflector 2.
  • the actual losses in the foam and on the skin areas of the aperture surface 12 and the reflectors 1 and 2 can be exactly determined after a model measurement in the corresponding frequency band. Area efficiency of the antennas of around 50% can be expected. The space between the subreflector 2 and the exciter horn 7 is not disturbed by any discontinuities, so that very good cross-polarization and secondary radiation behavior can be achieved. This is a great advantage of the directional antenna constructed according to the invention.
  • the aperture surface 12, which consists of a skin 3 which is preferably somewhat thinner ( ⁇ 0.5 mm), can be designed by inclination 16 and possibly by spatial structures such as knobs 13 in such a way that no disturbing reflection at the feed point of the antenna is brought about by this.

Abstract

The reflector surfaces (1, 2) of the dual reflector directional antenna (Cassegrain antenna, Gregory antenna) are mounted according to the invention on a plastic-foam body (4), which is enclosed by a sealed skin (3) and is matched in terms of its external shape to the contours of the two reflectors (main reflector with a central opening, catchment reflector), the body (4) having a cut-out for holding an excitation horn emitter (7) in the region of the central opening (5) of the main reflector (1). The antenna according to the invention, which is externally closed, is very stable because of its shell structure and can be produced using an integral-foam process, is suitable for use as a directional radio antenna, TV antenna or radar antenna. <IMAGE>

Description

Die Erfindung bezieht sich auf eine nach außen geschlossene Zweireflektor-Richtantenne (Cassegrain-Antenne, Gregory-Antenne) mit einem die Form eines Rotationsparaboloidausschnitts aufweisenden Hauptreflektor, einem Fangreflektor und einem durch eine zentrale Öffnung des Hauptreflektors durchgeführten Erregerhornstrahler.The invention relates to an externally closed two-directional directional antenna (Cassegrain antenna, Gregory antenna) with a main reflector having the shape of a paraboloid of revolution, a catch reflector and an exciter horn antenna that is passed through a central opening of the main reflector.

In zunehmendem Maße werden Parabolspiegelantennen für Richtfunkverbindungen in den Frequenzbändern P, K, R eingesetzt, in denen kleine Spiegeldurchmesser von 0,4 m bis 1,2 m zumeist ausreichen. Daneben bringt die Einführung von TV-Satelliten einen Bedarf von X-Band-Spiegelantennen mit einem Spiegeldurchmesser von 0,9 - 1,2 m. Die meisten Anwendungen derartiger Spiegelantennen erfordern entweder dual lineare Polarisation oder z.B. bei der TV-Anwendung links/rechts zirkulare Polarisation bei guten elektrischen Spezifikationswerten.Parabolic mirror antennas are increasingly being used for directional radio connections in the frequency bands P, K, R, in which small mirror diameters of 0.4 m to 1.2 m are usually sufficient. In addition, the introduction of TV satellites brings a need for X-band mirror antennas with a mirror diameter of 0.9 - 1.2 m. Most applications of such mirror antennas require either dual linear polarization or e.g. in the TV application left / right circular polarization with good electrical specification values.

Richtfunkspiegelantennen mit sogenanntem High Performance-Verhalten bestehen in üblicher Weise in ihrem mechanischen Aufbau aus drei Haupteinheiten. Die erste Einheit ist der Hauptreflektor, welcher ein Ausschnitt aus einem Rotationsparaboloid ist und in einigen Fällen korrigiert sein kann. Die zweite Einheit bildet die Erregereinheit, die mit einem Hilfsspiegel integriert sein kann. Die dritte Haupteinheit besteht aus einem Radom mit Absorberkragen, Blenden, Stützen für den Erreger, Druckluftdichtung usw. Diese drei Haupteinheiten müssen in aufwendiger Weise durch präzise mechanische Konstruktionen exakt zueinander montiert werden. Außerdem sind besondere Schutzmaßnahmen erforderlich, da solche Richtantennen gewöhnlich für den Allwettereinsatz auf Türmen ausgelegt werden müssen.Microwave antennas with so-called high performance behavior usually consist of three main units in their mechanical design. The first unit is the main reflector, which is a section of a paraboloid of revolution and can be corrected in some cases. The second unit is the excitation unit, which can be integrated with an auxiliary mirror. The third main unit consists of a radome with an absorber collar, screens, supports for the exciter, compressed air seal, etc. These three Main units have to be assembled to each other in a complex manner using precise mechanical designs. In addition, special protective measures are required, since such directional antennas usually have to be designed for all-weather use on towers.

Aufgabe der Erfindung ist es, für den Aufbau verhältnismäßig kleiner Zweispiegel-Richtantennen mit High Performance-Verhalten eine neue Technik aufzuzeigen, die bei relativ geringen Herstellungskosten eine hohe Präzision verbürgt, die insbesondere bei der TV-Anwendung, auch bei großen Serien, einfach eingehalten werden kann.The object of the invention is to show a new technology for the construction of relatively small two-directional directional antennas with high performance behavior, which guarantees high precision at relatively low manufacturing costs, which are easy to maintain, particularly in the TV application, even in large series can.

Gemäß der Erfindung, die sich auf eine Zweireflektor-Richtantenne (Cassegrain-Antenne, Gregory-Antenne) der eingangs genannten Art bezieht, wird diese Aufgabe dadurch gelöst, daß die metallischen Reflektorflächen auf einem von einer verdichteten Haut umschlossenen und hinsichtlich seiner Außenform an die Kontur des Hauptreflektors und die Kontur des Fangreflektors angepaßten Kunststoffschaumkörper aufgebracht sind, der im Bereich der zentralen Öffnung des Hauptreflektors eine Ausformung zur Aufnahme des Erregerhornstrahlers aufweist.According to the invention, which relates to a two-directional directional antenna (Cassegrain antenna, Gregory antenna) of the type mentioned, this object is achieved in that the metallic reflector surfaces on a surrounded by a compacted skin and its outer shape to the contour of the main reflector and the contour of the catch reflector are matched plastic foam body which has a shape in the region of the central opening of the main reflector for receiving the exciter horn.

Der Schaumkörper besteht beispielsweise aus Polyurethan- . Hartschaum. Ein solcher Körper ist nach dem Integralschaumverfahren in einer vorzugsweise selektiv beheizbaren Form herstellbar.The foam body is made of polyurethane, for example. Rigid foam. Such a body can be produced in a preferably selectively heatable form by the integral foam process.

Die Reflektorflächen lassen sich durch ein geeignetes Verfahren metallisieren und durch Schutzschichten fixieren.The reflector surfaces can be metallized using a suitable process and fixed using protective layers.

Der Erregerhornstrahler, der auch als offener Rundhohlleiter ausgebildet sein kann, läßt sich in eine mitgeformte Halterung einschrauben..Der Erregerhornstrahler mit seinem Flansch läßt sich auch durch Metallisierung einer entsprechenden Struktur des Schaumkörpers bilden. Es sind allerdings auch vorgeformte Metallflächen als Einlegeteile für die Realisierung der beiden Reflektoren möglich.The exciter horn radiator, which can also be designed as an open circular waveguide, can be screwed into a molded holder. The exciter horn radiator with its flange can also be removed by metallization form the speaking structure of the foam body. However, preformed metal surfaces are also possible as inserts for the implementation of the two reflectors.

Der Kunststoffschaumkörper weist im Bereich der Apertur des Erregerhornstrahlers in vorteilhafter Weise keine verdichtete Haut auf.The plastic foam body advantageously has no densified skin in the area of the aperture of the exciter horn.

Die Richtantenne nach der Erfindung bildet durch ihre Schalenstruktur eine sehr stabile Einheit. Der Herstellungsprozess liefert eine der Güte der Form entsprechende exakte Zuordnung des Reflektor-Erregersystems.Due to its shell structure, the directional antenna according to the invention forms a very stable unit. The manufacturing process provides an exact assignment of the reflector excitation system that corresponds to the quality of the shape.

Es ist ohne Schwierigkeiten möglich, an allen Stellen im Volumen der Richtantenne nach der Erfindung elektrisch wirksame Teile exakt und geschützt zu positionieren, um die Eigenschaften der Antenne, z.B. deren Nebenstrahlungsverhalten, zu verbessern. Durch Ausformung, Verdichtung es Materials, Beschichtung mit verlustreichem Material, Metallisierung oder dergleichen an beliebigen Stellen des Schaumkörpers lassen sich derartige elektrisch wirksame Teile so positionieren, daß sich eine gezielt gewünschte Verbesserung des Strahlungsverhaltens der Antenne ergibt. Gestaltet man Bereiche des Schaumkörpers pyramidenförmig, z.B. am Rande der Antenne, und beschichtet mit verlustreichem Material oder metallisiert blendenartige Gebilde, formt Abweichungen von der kreisförmigen Apertur usw., so ist eine gezielte Verminderung der Neben- und Rückstrahlung der Richtantenne erreichbar. Alle diese Maßnahmen sind bei wesentlich geringerem Aufwand im Vergleich zu dem bekannten Verfahren bei der Metallbearbeitung durch das Schäumen in einer entsprechenden Form exakt reproduzierbar. Insbesondere lassen sich auch an Stellen im dreidimensionalen Raumvolumen des Hauptreflektors wettergeschützt "quasi frei" hängende und sonst durch störende Stützen zu haltende Teile anbringen, die z.B. nach Entfernen von für den Schäumungsvorgang montierten Hilfsstreben im Schaumkörper störungsarm fixiert sind. Beispielsweise können solche "quasi frei" hängenden Teile Drähte oder Metallstäbe für ein polarisierendes Gitter im Bereich der Antennenapertur sein.It is possible without difficulty to position electrically effective parts exactly and protected at all points in the volume of the directional antenna according to the invention in order to improve the properties of the antenna, for example its secondary radiation behavior. By shaping, compressing the material, coating with lossy material, metallization or the like at any point on the foam body, such electrically effective parts can be positioned in such a way that a specifically desired improvement in the radiation behavior of the antenna results. If you design areas of the foam body in a pyramid shape, for example at the edge of the antenna, and coat them with lossy material or metallized screen-like structures, form deviations from the circular aperture, etc., then a targeted reduction of the secondary and back radiation of the directional antenna can be achieved. All of these measures can be reproduced exactly in a corresponding form with much less effort compared to the known method in metal processing by foaming. In particular, it can also be protected from the weather in places in the three-dimensional volume of the main reflector Attach "quasi free" hanging parts that are otherwise to be held by disruptive supports, which are fixed in the foam body with little interference, for example after removal of auxiliary struts mounted for the foaming process. For example, such "quasi free" hanging parts can be wires or metal rods for a polarizing grating in the area of the antenna aperture.

Die Erfindung wird im folgenden anhand eines in einer Figur dargestellten Ausführungsbeispiels erläutert.The invention is explained below with reference to an embodiment shown in a figure.

Die Figur zeigt in einer geschnittenen Seitenansicht einen Ausschnitt einer Zweireflektor-Richtantenne, die nach dem Cassegrain-Prinzip aufgebaut ist. Diese Antenne besteht aus einem Schaumkörper 4, beispielsweise aus Polyurethan-Hartschaum, der von einer verdichteten Haut 3 umschlossen ist, welche die Kontur eines Parabolreflektorausschnitts zur Anbringung eines entspechend geformten Hauptreflektors 1 und die Kontur eines Fangreflektors 2 aufweist und zusätzliche Funktionseinheiten bildet. Der Schaumkörper 4 läßt sich nach dem Integralschaumverfahren in einer vorzugsweise selektiv beheizbaren Form herstellen. Die Reflektorflächen 1 und 2 sind im Ausführungsbeispiel durch eine Metallisierungsschicht gebildet und werden durch Schutzschichten fixiert. Ein Erregerhornstrahler 7 ist in eine'Ausformung 6 eingeführt, welche als Halterung ausgebildet ist, mit welcher der einen Schraubflansch 9 aufweisende Erregerhornstrahler 7 als Einlegeteil verschraubt ist. Die Ausformung 6 zur Aufnahme des Erregerhornstrahlers 7 liegt im Bereich einer zentralen Öffnung 5 des Hauptreflektors 1. Im Bereich der Apertur 8 des Erregerhornstrahlers 7 weist der Kunststoffschaumkörper 4 keine verdichtete Haut auf. Am Rand der Antenne sind Bereiche 10 des Schaumkörpers 4 pyramidenförmig gestaltet und außerdem durch Metallisierung in der Figur gestrichelt dargestellte blendenartige Gebilde 11 vorgesehen, so daß eine gezielte Verbesserung des Neben- und Rückstrahlungsverhaltens der Antenne erreichbar wird. An der Rückseite des Kunststoffschaumkörpers 4 sind Verstärkungen 14 für die Montage und in Verlängerung der Ausformung 6 nach hinten Gehäuseteile 15 angeschäumt, welche als Raum zur Aufnahme einer Polarisationsweiche, von Elektronikbaugruppen und Montageteilen dienen können.The figure shows in a sectional side view a section of a two-reflector directional antenna which is constructed according to the Cassegrain principle. This antenna consists of a foam body 4, for example made of rigid polyurethane foam, which is enclosed by a compressed skin 3, which has the contour of a parabolic reflector cutout for attaching a correspondingly shaped main reflector 1 and the contour of a catch reflector 2 and forms additional functional units. The foam body 4 can be produced by the integral foam process in a preferably selectively heatable form. In the exemplary embodiment, the reflector surfaces 1 and 2 are formed by a metallization layer and are fixed by protective layers. An exciter horn 7 is inserted into a shape 6, which is designed as a holder, with which the exciter horn 7, which has a screw flange 9, is screwed as an insert. The shape 6 for receiving the exciter horn 7 lies in the area of a central opening 5 of the main reflector 1. In the area of the aperture 8 of the exciter horn 7, the plastic foam body 4 has no compacted skin. At the edge of the antenna, areas 10 of the foam body 4 are designed pyramid-shaped and also by metallization in the figure Aperture-like structures 11 shown in broken lines are provided, so that a targeted improvement in the secondary and retroreflective behavior of the antenna can be achieved. On the back of the plastic foam body 4, reinforcements 14 for the assembly and in the extension of the molding 6 to the rear are foamed housing parts 15, which can serve as a space for accommodating a polarization switch, electronic assemblies and assembly parts.

Für einen Hauptreflektor 1 mit einem f/D-Verhältnis von 0,25 (f = Brennweite, D= Hauptreflektordurchmesser) sind in der nachfolgenden Tabelle Werte zusammengestellt:For a main reflector 1 with an f / D ratio of 0.25 (f = focal length, D = main reflector diameter), the following table summarizes values:

Figure imgb0001
Je nach Herstellungsbedingungen besteht die Haut 3 im Ausführungsbeispiel aus einer etwa 0,5 - 1 mm starken porenfreien Schicht, die in einem Bereich von etwa 7 mm in den Schaum gleichmäßiger Dichte von etwa 40 kg/m3 übergeht. Verstärkungen für die Mastmontage oder dergl. lassen sich durch Einlegeteile in die Schäumvorrichtung vorsehen. Insgesamt bildet die Antenne nach der Erfindung eine dichte Einheit, die nur an ihrer Rückseite von einem Speisehohlleiter 17 und möglicherweise an der Frontseite durch eine Abgleichvorrichtung, die im Scheitel des Fangreflektors 2 wirkt, durchbrochen wird.
Figure imgb0001
 Depending on the manufacturing conditions, the skin 3 in the exemplary embodiment consists of an approximately 0.5-1 mm thick non-porous layer which, in a region of approximately 7 mm, merges into the foam of uniform density of approximately 40 kg / m 3 . Reinforcements for mast assembly or the like can be provided by inserting parts into the foaming device. Overall, the antenna according to the invention forms a dense unit, which is broken only on its rear side by a feed waveguide 17 and possibly on the front side by a balancing device which acts in the apex of the catch reflector 2.

Der bei den bekannten Cassegrain-Antennen mit Luft gefüllte Raum zwischen dem Hauptreflektor 1, dem Subreflektor 2 und dem Erregerhornstrahler 7 hat im Ausführungsbeispiel der Erfindung durch den Schaum ein tg δ von etwa 0,0001 bis 0,001 bei einer Dielektrizitätskonstante εr von 1,04 bis 1,25. Für den Großteil des Raumes 4 gelten Werte von ≈ 1,04 und tg δ ≈ 0,0001. Vor den metallischen Reflektorflächen 1 und 2 verdichtet sich das Medium des Schaumkörpers 4 stetig zur Haut 3. Eventuelle Änderungen der Amplituden/Phasenbedingungen im Vergleich zu einer gedachten, mit Luft gefüllten Richtantenne sind durch Korrekturen am Hauptreflektor 1 oder am Fangreflektor 2 kompensierbar. Die tatsächlichen Verluste im Schaum und an den Hautbezirken der Aperturfläche 12 und der Reflektoren 1 und 2 sind nach einer Modellmessung im entsprechenden Frequenzband exakt bestimmbar. Es ist mit Flächenwirkungsgraden der Antennen von etwa 50 % zu rechnen. Der Raum zwischen dem Subreflektor 2 und dem Erregerhornstrahler 7 wird durch keine Diskontinuitäten gestört, so daß ein sehr gutes Kreuzpolarisations- und Nebenstrahlungsverhalten erreichbar ist. Dies ist ein großer Vorteil der gemäß der Erfindung aufgebauten Richtantenne. Die Aperturfläche.12, die aus einer vorzugsweise etwas dünner geformten Haut 3 besteht ( < 0,5 mm), kann durch Neigung 16 und evtl. durch räumliche Strukturen, wie Noppen 13, so gestaltet werden, daß keine störende Reflexion am Speisepunkt der Antenne dadurch bewirkt wird.In the case of the known Cassegrain antennas, the space between the main reflector 1, the subreflector 2 and the excitation horn antenna 7 filled with air in the exemplary embodiment of the invention has a tg δ of approximately 0.0001 to 0.001 with a dielectric constant ε r of 1.04 due to the foam to 1.25. For the majority of room 4, values of ≈ 1.04 and tg δ ≈ 0.0001 apply. In front of the metallic reflector surfaces 1 and 2, the medium of the foam body 4 steadily condenses to the skin 3. Any changes in the amplitudes / phase conditions compared to an imaginary directional antenna filled with air can be compensated for by corrections to the main reflector 1 or the catch reflector 2. The actual losses in the foam and on the skin areas of the aperture surface 12 and the reflectors 1 and 2 can be exactly determined after a model measurement in the corresponding frequency band. Area efficiency of the antennas of around 50% can be expected. The space between the subreflector 2 and the exciter horn 7 is not disturbed by any discontinuities, so that very good cross-polarization and secondary radiation behavior can be achieved. This is a great advantage of the directional antenna constructed according to the invention. The aperture surface 12, which consists of a skin 3 which is preferably somewhat thinner (<0.5 mm), can be designed by inclination 16 and possibly by spatial structures such as knobs 13 in such a way that no disturbing reflection at the feed point of the antenna is brought about by this.

Claims (17)

1. Nach außen geschlossene Zweireflektor-Richtantenne (Cassegrain-Antenne, Gregory-Antenne) mit einem die Form eines Rotationsparaboloidausschnitts aufweisenden Hauptreflektor, einem Fangreflektor und einem durch eine zentrale Öffnung des Hauptreflektors durchgeführten Erregerhornstrahler,
dadurch gekennzeichnet, daß die metallischen Reflektorflächen (1,2) auf einem von einer verdichteten Haut (3) umschlossenen und hinsichtlich seiner Außenform an die Kontur des Hauptreflektors (1) und die Kontur des Fangreflektors (2) angepaßten Kunststoffschaumkörper (4) aufgebracht sind, der im Bereich der zentralen Öffnung (5) des Hauptreflektors (1) eine Ausformung (6) zur Aufnahme des Erregerhornstrahlers (7) aufweist.1. Two-directional directional antenna (Cassegrain antenna, Gregory antenna), which is closed to the outside, with a main reflector which has the shape of a paraboloid of revolution, a catch reflector and an exciter horn antenna which is passed through a central opening in the main reflector,
characterized in that the metallic reflector surfaces (1, 2) are applied to a plastic foam body (4) which is enclosed by a compacted skin (3) and whose outer shape is adapted to the contour of the main reflector (1) and the contour of the catch reflector (2), which in the area of the central opening (5) of the main reflector (1) has a shape (6) for receiving the exciter horn (7). 2. Richtantenne nach Anspruch 1,
dadurch gekennzeichnet, daß der Kunststoffschaumkörper (4) im Bereich der Apertur (8) des Erregerhornstrahlers (7) keine verdichtete Haut aufweist.2. directional antenna according to claim 1,
characterized in that the plastic foam body (4) has no densified skin in the region of the aperture (8) of the exciter horn (7). 3. Richtantenne nach Anspruch 1 oder 2,
dadurch gekennzeichnet, daß die Reflektorflächen (1,2) durch eine Metallisierungsschicht gebildet sind.3. Directional antenna according to claim 1 or 2,
characterized in that the reflector surfaces (1, 2) are formed by a metallization layer. 4. Richtantenne nach Anspruch 3,
dadurch gekennzeichnet, daß auf den Metallisierungsschichten noch jeweils eine Schutzschicht zur Fixierung vorgesehen ist.4. directional antenna according to claim 3,
characterized in that a protective layer is also provided for fixation on the metallization layers. 5. Richtantenne. nach Anspruch 1 oder 2,
dadurch gekennzeichnet, daß die Reflektorflächen (1,2) durch vorgeformte Metallflächen gebildet sind, welche als Einlegeteile auf die verdichtete Haut (3) des Schaumkörpers (4) verwendet werden.5. Directional antenna. according to claim 1 or 2,
characterized in that the reflector surfaces (1, 2) are formed by preformed metal surfaces which are used as inserts on the compressed skin (3) of the foam body (4). 6. Richtantenne nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Ausformung (6) zur Aufnahme des Erregerhornstrahlers (7) im Schaumkörper (4) als Halterung ausgebildet ist, mit welcher der einen Schraubflansch (9) aufweisende Erregerhornstrahler (7) verschraubbar ist.6. Directional antenna according to one of the preceding claims, characterized in that the shape (6) for receiving the exciter horn (7) in the foam body (4) is designed as a holder with which the screw flange (9) having exciter horn (7) can be screwed . 7. Richtantenne nach einem der Ansprüche 1 bis 5,
dadurch gekennzeichnet, daß der Erregerhornstrahler (7) durch eine Metallisierungsschicht gebildet ist, welche auf der geeignet strukturierten Ausformung (6) im Schaumkörper (4) aufgebracht ist.7. directional antenna according to one of claims 1 to 5,
characterized in that the exciter horn (7) is formed by a metallization layer which is applied to the suitably structured formation (6) in the foam body (4). 8. Richtantenne nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß an beliebigen Stellen der Schaumkörper (4) durch Ausformung, Verdichtung des Materials, Beschichtung mit verlustreichem Material, Metallisierung oder dergleichen elektrisch wirksame Teile so positioniert sind, daß sich eine gezielt gewünschte Verbesserung des Antennenstrahlungsverhaltens ergibt.8. Directional antenna according to one of the preceding claims, characterized in that at any point of the foam body (4) by molding, compression of the material, coating with lossy material, metallization or the like electrically effective parts are positioned so that a specifically desired improvement of Antenna radiation behavior results. 9. Richtantenne nach Anspruch 8,
dadurch gekennzeichnet, daß insbesondere am Antennenrand Bereiche (10) des Schaumkörpers (4) pyramidenförmig gestaltet sind.9. directional antenna according to claim 8,
characterized in that regions (10) of the foam body (4) in particular are designed pyramid-shaped at the edge of the antenna. 10. Richtantenne nach Anspruch 8,
gekennzeichnet durch die Metallisierung blendenartiger Gebilde'(11).10. Directional antenna according to claim 8,
characterized by the metallization of aperture-like structures' (11). 11. Richtantenne nach Anspruch 8,
gekennzeichnet durch Abweichungen des Schaumkörpers (4) von der kreisförmigen Apertur.11. Directional antenna according to claim 8,
characterized by deviations of the foam body (4) from the circular aperture. 12. Richtantenne nach Anpruch 8,
dadurch gekennzeichnet, daß insbesondere auch an Stellen im dreidimensionalen Raumvolumen des Hauptreflektors (1) wettergeschützt "quasi frei" hängende und sonst durch störende Stützen zu haltende Teile angebracht sind, die z.B. nach Entfernen von für den Schäumungsvorgang montierten Hilfsstreben im Schaumkörper (4) störungsarm fixiert sind.12. Directional antenna according to Claim 8,
characterized in that in particular also in places in the three-dimensional spatial volume of the main reflector (1) weather-proof "quasi freely" hanging parts which are otherwise to be held by disruptive supports are attached, which, for example after removal of auxiliary struts mounted for the foaming process, are fixed in the foam body (4) with little interference are. 13. Richtantenne nach Anspruch 12,
dadurch gekennzeichnet, daß die "quasi frei" hängenden Teile Drähte oder Metallstäbe für ein polarisierendes Gitter im Bereich der Apertur sind.13. Directional antenna according to claim 12,
characterized in that the "quasi free" hanging parts are wires or metal rods for a polarizing grating in the area of the aperture. 14. Richtantenne nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die verdichtete Haut (3) auf der Aperturfläche (12) des Schaumkörpers (4) dünner ausgebildet ist als in den übrigen Bereichen des Schaumkörpers.14. Directional antenna according to one of the preceding claims, characterized in that the compressed skin (3) on the aperture surface (12) of the foam body (4) is formed thinner than in the other areas of the foam body. 15. Richtantenne nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Aperturfläche des Schaumkörpers (4) durch Neigung (16) und/oder räumliche Struktur, wie z.B. Noppen (13), so gestaltet ist, daß keine störenden Reflexionen an der Antennenspeisestelle hervorgerufen werden.15. Directional antenna according to one of the preceding claims, characterized in that the aperture surface of the foam body (4) by inclination (16) and / or spatial structure, such as e.g. Knobs (13), is designed so that no disturbing reflections are caused at the antenna feed point. 16. Richtantenne nach .einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Schaumkörper (4) aus Polyurethan-Hartschaum besteht.16. Directional antenna according to one of the preceding claims, characterized in that the foam body (4) consists of rigid polyurethane foam. 17. Richtantenne nach einem der vorhergehenden Ansprüche, gekennzeichnet durch eine Herstellung nach dem Integralschaumverfahren in einer vorzugsweise selektiv beheizbaren Form.17. Directional antenna according to one of the preceding claims, characterized by a production according to the integral foam process in a preferably selectively heatable form.
EP84115744A 1984-07-13 1984-12-18 Dual reflector directional antenna Ceased EP0170726A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3425945 1984-07-13
DE3425945 1984-07-13

Publications (1)

Publication Number Publication Date
EP0170726A1 true EP0170726A1 (en) 1986-02-12

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Application Number Title Priority Date Filing Date
EP84115744A Ceased EP0170726A1 (en) 1984-07-13 1984-12-18 Dual reflector directional antenna

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EP (1) EP0170726A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0452077A1 (en) * 1990-04-09 1991-10-16 Marconi Electronic Devices Limited Antenna arrangements
EP2615688A1 (en) * 2010-09-07 2013-07-17 Comba Telecom System (China) Ltd. Microwave antenna and its outer cover
WO2017152988A1 (en) * 2016-03-10 2017-09-14 Telefonaktiebolaget Lm Ericsson (Publ) A reflector antenna arrangement
WO2020160763A1 (en) * 2019-02-06 2020-08-13 Rosemount Tank Radar Ab Antenna for a radar level gauge system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2246650A1 (en) * 1971-09-22 1973-03-29 Thomson Csf APLANATIC HIGH FREQUENCY ANTENNA
DE2240893A1 (en) * 1972-08-19 1974-03-07 Gruenzweig & Hartmann MIRROR ANTENNA, IN PARTICULAR FOR THE 12 GHZ BAND
DE2821375A1 (en) * 1977-05-20 1978-11-30 Philips Nv METHOD FOR MANUFACTURING A PLASTIC REFLECTOR AND DEVICE FOR IMPLEMENTING IT
EP0084420A2 (en) * 1982-01-19 1983-07-27 P.A. Consulting Services Limited An antenna, particularly for the reception of satellite communications
DE3231097A1 (en) * 1982-08-20 1984-02-23 Siemens AG, 1000 Berlin und 8000 München Antenna in accordance with the Cassegrain principle, having a holder for the subreflector
EP0108515A1 (en) * 1982-10-11 1984-05-16 Cambridge Electronic Industries plc Dish aerial

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2246650A1 (en) * 1971-09-22 1973-03-29 Thomson Csf APLANATIC HIGH FREQUENCY ANTENNA
DE2240893A1 (en) * 1972-08-19 1974-03-07 Gruenzweig & Hartmann MIRROR ANTENNA, IN PARTICULAR FOR THE 12 GHZ BAND
DE2821375A1 (en) * 1977-05-20 1978-11-30 Philips Nv METHOD FOR MANUFACTURING A PLASTIC REFLECTOR AND DEVICE FOR IMPLEMENTING IT
EP0084420A2 (en) * 1982-01-19 1983-07-27 P.A. Consulting Services Limited An antenna, particularly for the reception of satellite communications
DE3231097A1 (en) * 1982-08-20 1984-02-23 Siemens AG, 1000 Berlin und 8000 München Antenna in accordance with the Cassegrain principle, having a holder for the subreflector
EP0108515A1 (en) * 1982-10-11 1984-05-16 Cambridge Electronic Industries plc Dish aerial

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0452077A1 (en) * 1990-04-09 1991-10-16 Marconi Electronic Devices Limited Antenna arrangements
WO1991015880A1 (en) * 1990-04-09 1991-10-17 Marconi Electronic Devices Limited Antenna arrangements
EP2615688A1 (en) * 2010-09-07 2013-07-17 Comba Telecom System (China) Ltd. Microwave antenna and its outer cover
EP2615688A4 (en) * 2010-09-07 2014-07-16 Comba Telecom System China Ltd Microwave antenna and its outer cover
WO2017152988A1 (en) * 2016-03-10 2017-09-14 Telefonaktiebolaget Lm Ericsson (Publ) A reflector antenna arrangement
US10263343B2 (en) 2016-03-10 2019-04-16 Telefonaktiebolaget Lm Ericsson (Publ) Reflector antenna arrangement
WO2020160763A1 (en) * 2019-02-06 2020-08-13 Rosemount Tank Radar Ab Antenna for a radar level gauge system

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