EP0086399B1 - Aerial with several reflectors - Google Patents
Aerial with several reflectors Download PDFInfo
- Publication number
- EP0086399B1 EP0086399B1 EP83100957A EP83100957A EP0086399B1 EP 0086399 B1 EP0086399 B1 EP 0086399B1 EP 83100957 A EP83100957 A EP 83100957A EP 83100957 A EP83100957 A EP 83100957A EP 0086399 B1 EP0086399 B1 EP 0086399B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- radiators
- reflector
- individual
- group
- auxiliary
- 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
Links
- 230000005855 radiation Effects 0.000 claims description 29
- 230000010287 polarization Effects 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Classifications
-
- 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
Definitions
- the invention relates to a multi-reflector antenna for a geostationary satellite, with a parabolic main reflector, at least one auxiliary reflector and a number of individual emitters which emit on the main reflector in the direction of different target areas on earth, the entirety of the individual emitters being formed into a plurality of adjacent individual emitters Spotlight groups is divided.
- Multi-reflector antennas which are carried by geostationary communication satellites, are intended to illuminate a coverage area below them on the earth's surface, subject to certain conditions. This is done by a number of radiation lobes. the neighboring target areas are assigned. Each lobe is generated by a single radiator, the radiation of which is directed from the main reflector to the corresponding target area. Each lobe illuminates the generally circular target area assigned to it on the surface of the earth in such a way that the incident radiation intensity falls radially outwards from the center of this target area. Adjacent radiation lobes overlap in their outer areas and are closer to each other the less the drop in intensity at the edges of a target area should be.
- a multi-reflector antenna in which an intermediate reflector is switched between the individual radiators and the parabolic main reflector, which deflects the radiation of the individual radiators towards the main reflector. Both the main and the intermediate reflector are offset with respect to the parabolic axis, so that shadowing of the radiation emanating from the main reflector is avoided by the intermediate reflector.
- a central single radiator is directed so that its radiation is centered on the centers of the intermediate and the main reflector and leaves the latter parallel to the parabolic axis assigned to the main reflector.
- the individual emitters adjacent to this central single emitter are directed such that their radiation after reflection by the intermediate reflector is also centered on the center of the main reflector, but is reflected by the latter in different spatial directions that are not parallel to the parabolic axis.
- a single antenna for such two-reflector antennas which are assigned to the Cassegrain or Gregory type, are usually used horn antenna.
- the dimensions of these, in particular with regard to their aperture, depend on the frequency and the reflector diameters. For this reason, the individual radiators cannot be moved as close together as desired. However, this proves to be very cumbersome if the requirement is to be met that the radiation drop at the edges of the adjacent target areas on the earth's surface should not exceed a certain predetermined value.
- the stricter the requirements in this regard the closer the lobes, the width of which is approximately fixed at a given frequency and diameter of the main reflector, must be close together.
- the radiation intensity in the target area should not drop by more than 3 dB, for example, this is the case with the arrangement described above far no longer realizable.
- a multi-reflector antenna of the type mentioned is known.
- This is also a two-reflector antenna, in which the entirety of the individual radiators directed at the auxiliary reflector is, however, broken down into radiator groups of adjacent individual radiators.
- the individual emitters of a radiation group are also assigned adjacent radiation lobes or target areas. Since the individual emitters have certain minimum dimensions purely geometrically, the radiation lobes cannot move as close together as desired and thus only overlap to a limited extent. It follows from this that in the target area, with increasing distance from the center of the radiation lobe, the intensity of the received radiation power decreases more and more until the intensity in the area of the neighboring radiation lobe rises again. On the other hand, there is a requirement that the intensity drops in the area of a radiation lobe should be as small as possible.
- the invention has for its object to provide a multi-reflector antenna of the type mentioned, with which it is possible to illuminate a larger target area on the earth with the help of overlapping radiation lobes so that the occurring drops in intensity can be kept as low as possible.
- each radiator group is assigned its own auxiliary reflector, which is irradiated by the individual radiators of the group and reflects the radiation towards the main reflector, and the individual radiators are directed to each radiator group in such a way that neighboring target areas are supplied by individual radiators from different radiator groups .
- auxiliary reflectors are now used, each of which is assigned a radiator group consisting of individual radiators that are adjacent to one another.
- the individual emitters in a group of emitters no longer need to be aimed at directly adjacent, for example circular, target areas on the earth's surface.
- the gaps between the radiation lobes of one radiator group that arise with regard to the permissible intensity fluctuations can be supplied by appropriately aligned radiation lobes of other radiator groups. Immediately adjacent circular target areas are therefore served by individual emitters from different emitter groups.
- auxiliary reflectors When using three auxiliary reflectors, for example, there is a grid of circular, overlapping target areas on the surface of the earth, of which any one is supplied by a single radiator of the first radiator group and is surrounded in a symmetrical manner by six target areas, which alternate between the two other radiator groups are operated, with a total of three individual radiators from the second and the third radiator group being involved.
- This grid can also be traced back to a regular basic structure, which consists of three mutually displaced networks based on equilateral triangles, the centers of the radiation lobes assigned to the individual emitters each lying in the corner points.
- the grid from the target areas assigned to the individual radiators can be designed to be as complicated as desired.
- the spatial directions assigned to the individual radiators of a radiator group can be further apart in terms of angle, the more individual radiators are distributed over the more radiator groups or auxiliary reflectors.
- the auxiliary reflectors In the further configuration of the multi-reflector antenna according to the invention, it proves to be expedient to equip the auxiliary reflectors with curved reflector surfaces each having two focal points. It is important to ensure that one focal point coincides with the focal point of the parabolic main reflector and that the radiator group assigned to the auxiliary reflector is arranged at its other focal point.
- the radiator groups are all mapped onto the focal area of the parabolic main reflector.
- the reflector surfaces of the auxiliary reflectors can, according to the Cassegrain type, be excerpts from rotational hyperboloids or, according to the Gregory type, excerpts from rotational ellipsoids.
- optical multi-mirror systems instead of auxiliary reflectors, each of which must have two focal points.
- the invention is preferably applicable to multi-reflector antennas in an offset arrangement.
- the use of axisymmetric arrangements is also within the scope of the invention, although shadowing by the auxiliary reflectors must be accepted.
- the focal point axes given by the focal points of the auxiliary reflectors are inclined relative to the axis of the parabolic main reflector.
- a simple way of orienting several auxiliary reflectors is to arrange their other focal points on a tiny circular line of this type.
- completely identical reflector surfaces are used, which are only pivoted around different angles of rotation with respect to the axis of the parabolic main reflector.
- the inclination of the assigned focal axis with respect to the named axis is the same for all auxiliary reflectors.
- the focal point distances on the focal point axes assigned to the individual auxiliary reflectors can be at least partially different.
- the reflector surfaces of the individual auxiliary reflectors can therefore be based on differently curved rotational hyperboloids, the auxiliary reflectors can thus be arranged at different distances from the focal point of the parabolic main reflector.
- the inclinations of the focal axes can be different from the axis of the main reflector.
- auxiliary reflectors partially overlap each other. Then only care must be taken to ensure that these neighboring auxiliary reflectors are selective for orthogonal polarization directions or different frequency ranges.
- grid-like structures consisting of rigid or tensioned parallel metal strips can be used. If about three auxiliary reflectors are provided, of which the middle one at its two opposite edges is overlapped by one of the two outer edges, the latter can be designed, for example, for horizontal, the former for vertical polarization.
- auxiliary reflectors In a similar manner, frequency-selective reflectors known per se can be used as auxiliary reflectors which partially overlap one another.
- the invention also includes the case that one of the radiator groups resulting from the subdivision of the totality of the individual radiators is not assigned an auxiliary reflector, rather this radiator group is arranged at the focal point of the parabolic main reflector and illuminates it directly.
Landscapes
- Aerials With Secondary Devices (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
Description
Die Erfindung betrifft eine Mehrreflektorantenne für einen geostationären Satelliten, mit einem parabolischen Hauptreflektor, mindestens einem Hilfsreflektor und einer Anzahl von Einzelstrahlern, die über den Hauptreflektor in Richtung jeweils unterschiedlicher Zielgebiete auf der Erde abstrahlen, wobei die Gesamtheit der Einzelstrahler in mehrere von jeweils benachbarten Einzelstrahlern gebildete Strahlergruppen unterteilt ist.The invention relates to a multi-reflector antenna for a geostationary satellite, with a parabolic main reflector, at least one auxiliary reflector and a number of individual emitters which emit on the main reflector in the direction of different target areas on earth, the entirety of the individual emitters being formed into a plurality of adjacent individual emitters Spotlight groups is divided.
Mehrreflektorantennen, welche von geostationären Nachrichtensatelliten mitgeführt werden, sollen ein unter ihnen auf der Erdoberfläche gelegenes Versorgungsgebiet unter Einhaltung bestimmter Bedingungen ausleuchten. Dies geschieht durch eine Anzahl von Strahlungskeulen. die benachbarten Zielgebieten zugeordnet sind. Jede Strahlungskeule wird von einem Einzelstrahler erzeugt, dessen Strahlung vom Hauptreflektor auf das entsprechende Zielgebiet gelenkt wird. Jede Strahlungskeule leuchtet das ihr zugeordnete, im allgemeinen kreisförmige Zielgebiet auf der Erdoberfläche aus, und zwar derart, dass die einfallende Strahlungsintensität von der Mitte dieses Zielgebietes radial nach aussen hin abfällt. Benachbarte Strahlungskeulen überlappen sich in ihren Aussenbereichen und liegen um so enger beieinander, je geringer der Intensitätsabfall an den Rändern eines Zielgebietes sein soll.Multi-reflector antennas, which are carried by geostationary communication satellites, are intended to illuminate a coverage area below them on the earth's surface, subject to certain conditions. This is done by a number of radiation lobes. the neighboring target areas are assigned. Each lobe is generated by a single radiator, the radiation of which is directed from the main reflector to the corresponding target area. Each lobe illuminates the generally circular target area assigned to it on the surface of the earth in such a way that the incident radiation intensity falls radially outwards from the center of this target area. Adjacent radiation lobes overlap in their outer areas and are closer to each other the less the drop in intensity at the edges of a target area should be.
Aus der DE-OS-2 503 594 ist eine Mehrreflektorantenne bekannt, bei der zwischen den Einzelstrahlern und dem parabolischen Hauptreflektor ein Zwischenreflektor eingeschaltet ist, der die Strahlung der Einzelstrahler zum Hauptreflektor hin umlenkt. Sowohl der Haupt- als auch der Zwischenreflektor sind gegenüber der Parabolachse versetzt angeordnet, so dass eine Abschattung der vom Hauptreflektor ausgehenden Strahlung durch den Zwischenreflektor vermieden wird. Ein zentraler Einzelstrahler ist so gerichtet, dass seine Strahlung auf die Mitten des Zwischen- und des Hauptreflektors zentriert ist und letzteren parallel zu der dem Hauptreflektor zugeordneten Parabolachse verlässt. Die diesem zentralen Einzelstrahler benachbarten Einzelstrahler sind so gerichtet, dass ihre Strahlung nach Reflektion durch den Zwischenreflektor ebenfalls auf die Mitte des Hauptreflektors zentriert ist, von diesem aber in unterschiedliche Raumrichtungen reflektiert wird, die zur Parabolachse nicht parallel sind.From DE-OS-2 503 594 a multi-reflector antenna is known, in which an intermediate reflector is switched between the individual radiators and the parabolic main reflector, which deflects the radiation of the individual radiators towards the main reflector. Both the main and the intermediate reflector are offset with respect to the parabolic axis, so that shadowing of the radiation emanating from the main reflector is avoided by the intermediate reflector. A central single radiator is directed so that its radiation is centered on the centers of the intermediate and the main reflector and leaves the latter parallel to the parabolic axis assigned to the main reflector. The individual emitters adjacent to this central single emitter are directed such that their radiation after reflection by the intermediate reflector is also centered on the center of the main reflector, but is reflected by the latter in different spatial directions that are not parallel to the parabolic axis.
Ein Einzelstrahler für derartige Zweireflektorantennen, die dem Cassegrain- oder Gregory-Typ zuzuordnen sind, werden gewöhnlich Hornstrahler eingesetzt. Diese richten sich in ihren Abmessungen, insbesondere bezüglich ihrer Apertur, nach der Frequenz sowie den Reflektordurchmessern. Deswegen können die Einzelstrahler nicht beliebig dicht aneinandergerückt werden. Dies erweist sich aber als sehr hinderlich, wenn die Forderung zu erfüllen ist, dass der Strahlungsabfall an den Rändern der einander benachbarten Zielgebiete auf der Erdoberfläche einen bestimmten vorgegebenen Wert nicht überschreiten solle. Je strenger die Anforderungen in dieser Hinsicht sind, desto enger müssen die Strahlungskeulen, deren Breite bei vorgegebener Frequenz und Durchmesser des Hauptreflektors in etwa festliegt, beieinanderliegen. Soll bei einer Frequenz von 20 GHz und einem Durchmesser des Hauptreflektors von 4,2 m, woraus eine Halbwertbreite der Strahlungskeulen von 0,255° folgt, die Strahlungsintensität im Zielgebiet beispielsweise nirgends um mehr als 3 dB absinken, so ist dies mit der oben beschriebenen Anordnung bei weitem nicht mehr realisierbar.A single antenna for such two-reflector antennas, which are assigned to the Cassegrain or Gregory type, are usually used horn antenna. The dimensions of these, in particular with regard to their aperture, depend on the frequency and the reflector diameters. For this reason, the individual radiators cannot be moved as close together as desired. However, this proves to be very cumbersome if the requirement is to be met that the radiation drop at the edges of the adjacent target areas on the earth's surface should not exceed a certain predetermined value. The stricter the requirements in this regard, the closer the lobes, the width of which is approximately fixed at a given frequency and diameter of the main reflector, must be close together. If, at a frequency of 20 GHz and a diameter of the main reflector of 4.2 m, which results in a half-value width of the radiation lobes of 0.255 °, the radiation intensity in the target area should not drop by more than 3 dB, for example, this is the case with the arrangement described above far no longer realizable.
Aus der US-A-4 236 161 ist eine Mehrreflektorantenne der eingangs genannten Art bekannt. Auch hier handelt es sich um eine Zweireflektorantenne, bei der die auf den Hilfsreflektor gerichtete Gesamtheit der Einzelstrahler jedoch in Strahlergruppen einander benachbarter Einzelstrahler aufgegliedert ist. Den Einzelstrahlern einer.Strahiergruppe sind auch einander benachbarte Strahlungskeulen bzw. Zielgebiete zugeordnet. Da die Einzelstrahler rein geometrisch gewisse Mindestabmessungen besitzen, können die Strahlungskeulen nicht beliebig dicht aneinander rücken und sich somit nur in begrenztem Ausmass überlappen. Daraus folgt, dass im Zielgebiet mit zunehmender Entfernung vom Zentrum der Strahlungskeule immer stärkere Intensitätsabfälle der empfangenen Strahlungsleistung zu verzeichnen sind, bis die Intensität im Gebiet der benachbarten Strahlungskeule wieder ansteigt. Demgegenüber besteht aber die Forderung, dass die Intensitätsabfälle im Gebiet einer Strahlungskeule möglichst gering sein sollen.From US-A-4 236 161 a multi-reflector antenna of the type mentioned is known. This is also a two-reflector antenna, in which the entirety of the individual radiators directed at the auxiliary reflector is, however, broken down into radiator groups of adjacent individual radiators. The individual emitters of a radiation group are also assigned adjacent radiation lobes or target areas. Since the individual emitters have certain minimum dimensions purely geometrically, the radiation lobes cannot move as close together as desired and thus only overlap to a limited extent. It follows from this that in the target area, with increasing distance from the center of the radiation lobe, the intensity of the received radiation power decreases more and more until the intensity in the area of the neighboring radiation lobe rises again. On the other hand, there is a requirement that the intensity drops in the area of a radiation lobe should be as small as possible.
Aus der EP-A-0 028 018 (Fig. 7) ist eine Anordnung bekannt, die aus mehreren, direkt aneinandergerückten Zweireflektorantennen besteht. Diese weisen jeweils einen Haupt- und einen Hilfsreflektor auf, welcher wiederum jeweils von einem eigenen Einzelstrahler angestrahlt wird. Hierbei handelt es sich also lediglich um eine Anzahl von Zweireflektorantennen mit jeweils einem Einzelstrahler. Die Einzelstrahler sind relativ weit auseinandergerückt, da zu jedem Hauptreflektor jeweils nur ein Einzelstrahler gehört. Diese Anordnung ermöglicht nicht die Abstrahlung mehrerer Strahlungskeulen über einen einzigen Hauptreflektor und ist insofern wegen ihres verhältnismässig grossen Raumbedarfs kaum für die Anwendung bei Nachrichtensatelliten geeignet.From EP-A-0 028 018 (Fig. 7) an arrangement is known which consists of a plurality of two reflector antennas which are directly placed next to one another. These each have a main and an auxiliary reflector, which in turn is illuminated by its own individual radiator. This is therefore only a number of two-reflector antennas, each with a single radiator. The individual emitters are relatively far apart since only one individual emitter belongs to each main reflector. This arrangement does not allow the radiation of several radiation lobes via a single main reflector and is therefore hardly suitable for use with communications satellites because of its relatively large space requirement.
Der Erfindung liegt die Aufgabe zugrunde, eine Mehrreflektorantenne der eingangs genannten Art bereitzustellen, mit der es möglich ist, ein grösseres Zielgebiet auf der Erde mit Hilfe einander überlappender Strahlungskeulen so auszuleuchten, dass die auftretenden Intensitätsabfälle möglichst gering gehalten werden können.The invention has for its object to provide a multi-reflector antenna of the type mentioned, with which it is possible to illuminate a larger target area on the earth with the help of overlapping radiation lobes so that the occurring drops in intensity can be kept as low as possible.
Diese Aufgabe ist gemäss der Erfindung dadurch gelöst, dass jeder Strahlergruppe ein eigener, von den Einzelstrahlern der Gruppe angestrahlter und die Strahlung zum Hauptreflektor hin reflektierender Hilfsreflektor zugeordnet ist und die Einzelstrahler einer jeden Strahlergruppe so gerichtet sind, dass benachbarte Zielgebiete von Einzelstrahlern unterschiedlicher Strahlergruppen versorgt werden.This object is achieved according to the invention in that each radiator group is assigned its own auxiliary reflector, which is irradiated by the individual radiators of the group and reflects the radiation towards the main reflector, and the individual radiators are directed to each radiator group in such a way that neighboring target areas are supplied by individual radiators from different radiator groups .
Vorteilhafte Weiterbildungen der Erfindung sind den Unteransprüchen und dem einzigen nebengeordneten Anspruch zu entnehmen.Advantageous developments of the invention can be found in the subclaims and the only independent claim.
Anstelle eines einzigen Zwischenreflektors sind nunmehr mehrere Hilfsreflektoren verwendet, denen jeweils eine Strahlergruppe zugeordnet ist, die aus einander benachbarten Einzelstrahlern besteht. Die Einzelstrahler einer Strahlergruppe brauchen nun nicht mehr auf direkt benachbarte, beispielsweise etwa kreisförmige Zielgebiete auf der Erdoberfläche gerichtet zu sein. Die hinsichtlich der zulässigen Intensitätsschwankungen entstehenden Lücken zwischen den Strahlungskeulen einer Strahlergruppe können durch entsprechend ausgerichtete Strahlungskeulen anderer Strahlergruppen versorgtwerden. Unmittelbar benachbarte kreisförmige Zielgebiete werden also von Einzelstrahlern unterschiedlicher Strahlergruppen bedient. Bei der Verwendung von drei Hilfsreflektoren ergibt sich auf der Erdoberfläche beispielsweise ein Raster von kreisförmigen, sich am Rande überlappenden Zielgebieten, von denen ein beliebiges von einem Einzelstrahler der ersten Strahlergruppe versorgt wird und in symmetrischer Weise von sechs Zielgebieten umgeben ist, die abwechselnd von den beiden anderen Strahlergruppen bedient werden, wobei insgesamtjeweils drei Einzelstrahler der zweiten sowie der dritten Strahlergruppe beteiligt sind. Dieses Raster lässt sich auch auf eine regelmässige Grundstruktur zurückführen, die aus drei gegeneinander verschobenen Netzen auf der Basis gleichseitiger Dreiecke besteht, wobei in den Eckpunkten jeweils die Zentren der den Einzelstrahlern zugeordneten Strahlungskeulen liegen. Durch Vermehrung der Hilfsreflektoren lässt sich das Raster aus den den Einzelstrahlern zugeordneten Zielgebieten beliebig kompliziert gestalten.Instead of a single intermediate reflector, several auxiliary reflectors are now used, each of which is assigned a radiator group consisting of individual radiators that are adjacent to one another. The individual emitters in a group of emitters no longer need to be aimed at directly adjacent, for example circular, target areas on the earth's surface. The gaps between the radiation lobes of one radiator group that arise with regard to the permissible intensity fluctuations can be supplied by appropriately aligned radiation lobes of other radiator groups. Immediately adjacent circular target areas are therefore served by individual emitters from different emitter groups. When using three auxiliary reflectors, for example, there is a grid of circular, overlapping target areas on the surface of the earth, of which any one is supplied by a single radiator of the first radiator group and is surrounded in a symmetrical manner by six target areas, which alternate between the two other radiator groups are operated, with a total of three individual radiators from the second and the third radiator group being involved. This grid can also be traced back to a regular basic structure, which consists of three mutually displaced networks based on equilateral triangles, the centers of the radiation lobes assigned to the individual emitters each lying in the corner points. By increasing the number of auxiliary reflectors, the grid from the target areas assigned to the individual radiators can be designed to be as complicated as desired.
Die den Einzelstrahlern einer Strahlergruppe zugeordneten Raumrichtungen können winkelmässig umso weiter auseinanderliegen, auf je mehr Strahlergruppen bzw. Hilfsreflektoren die Gesamtheit der Einzelstrahler verteilt wird.The spatial directions assigned to the individual radiators of a radiator group can be further apart in terms of angle, the more individual radiators are distributed over the more radiator groups or auxiliary reflectors.
Bei der weiteren Ausgestaltung der Mehrreflektorantenne gemäss der Erfindung erweist es sich als zweckmässig, die Hilfsreflektoren mit gewölbten, je zwei Brennpunkte aufweisenden Reflektorflächen auszustatten. Dabei ist darauf zu achten, dass der eine Brennpunkt jeweils mit dem Brennpunkt des parabolischen Hauptreflektors zusammenfällt und die dem Hilfsreflektor jeweils zugeordnete Strahlergruppe an dessen anderem Brennpunkt angeordnet ist. Die Strahlergruppen werden damit sämtlich auf den Brennpunktsbereich des parabolischen Hauptreflektors abgebildet. Die Reflektorflächen der Hilfsreflektoren können, dem Cassegrain-Typ entsprechend, Ausschnitte aus Rotationshyperboloiden oder, dem Gregory-Typ entsprechend, Ausschnitte aus Rotationsellipsoiden sein. Es ist jedoch denkbar, anstelle von Hilfsreflektoren optische Mehrspiegelsysteme zu verwenden, die jeweils zwei Brennpunkte aufweisen müssen.In the further configuration of the multi-reflector antenna according to the invention, it proves to be expedient to equip the auxiliary reflectors with curved reflector surfaces each having two focal points. It is important to ensure that one focal point coincides with the focal point of the parabolic main reflector and that the radiator group assigned to the auxiliary reflector is arranged at its other focal point. The radiator groups are all mapped onto the focal area of the parabolic main reflector. The reflector surfaces of the auxiliary reflectors can, according to the Cassegrain type, be excerpts from rotational hyperboloids or, according to the Gregory type, excerpts from rotational ellipsoids. However, it is conceivable to use optical multi-mirror systems instead of auxiliary reflectors, each of which must have two focal points.
Die Erfindung ist bevorzugt auf Mehrreflektorantennen in Offset-Anordnung anwendbar. Allerdings liegt auch die Verwendung achsensymmetrischer Anordnungen im Bereich der Erfindung, wobei allerdings Abschattungen durch die Hilfsreflektoren in Kauf genommen werden müssen. Es ist vorteilhaft, wenn die durch die Brennpunkte der Hilfsreflektoren jeweils gegebenen Brennpunktachsen gegenüber der Achse des parabolischen Hauptreflektors geneigt sind. Durch Rotation einer derartigen Brennpunktachse um die Achse des parabolischen Hauptreflektors entsteht eine Kegelmantelfläche, deren Spitze vom Brennpunkt des parabolischen Hauptreflektors gebildet wird, der mit dem einen Brennpunkt der Reflektorfläche des Hilfsreflektors zusammenfällt, während der andere Brennpunkt eine koaxial zur Achse des parabolischen Hauptreflektors orientierte Kreislinie durchläuft. Eine einfache Möglichkeit der Orientierung mehrerer Hilfsreflektoren besteht nun darin, deren andere Brennpunkte sämtlich auf einer winzigen derartigen Kreislinie anzuordnen. Es werden in diesem Falle also völlig gleichartige Reflektorflächen verwendet, die lediglich um unterschiedliche Drehwinkel bezüglich der Achse des parabolischen Hauptreflektors herumgeschwenkt sind. Die Neigung der zugeordneten Brennpunktachsen gegenüber der genanten Achse ist jedoch bei allen Hilfsreflektoren dieselbe.The invention is preferably applicable to multi-reflector antennas in an offset arrangement. However, the use of axisymmetric arrangements is also within the scope of the invention, although shadowing by the auxiliary reflectors must be accepted. It is advantageous if the focal point axes given by the focal points of the auxiliary reflectors are inclined relative to the axis of the parabolic main reflector. By rotating such a focal axis about the axis of the parabolic main reflector, a conical surface is created, the tip of which is formed by the focal point of the parabolic main reflector, which coincides with the one focal point of the reflector surface of the auxiliary reflector, while the other focal point passes through a circular line oriented coaxially to the axis of the parabolic main reflector . A simple way of orienting several auxiliary reflectors is to arrange their other focal points on a tiny circular line of this type. In this case, completely identical reflector surfaces are used, which are only pivoted around different angles of rotation with respect to the axis of the parabolic main reflector. However, the inclination of the assigned focal axis with respect to the named axis is the same for all auxiliary reflectors.
Es sind jedoch auch andere, kompliziertere Ausführungsformen denkbar. So ist es möglich, dass die Brennpunktabstände auf den, den einzelnen Hilfsreflektoren zugeordneten Brennpunktachsen zumindest teilweise verschieden sind. Den Reflektorflächen der einzelnen Hilfsreflektoren können also unterschiedlich gekrümmte Rotationshyperboloide zugrundeliegen, die Hilfsreflektoren somit in unterschiedlichen Abständen vom Brennpunkt des parabolischen Hauptreflektors angeordnet sein. Weiterhin können die Neigungen der Brennpunktachsen gegenüber der Achse des Hauptreflektors verschieden sein. Insgesamt ergeben sich somit mannigfache Variationsmöglichkeiten bezüglich der Anordnung der Hilfreflektoren, so dass eine optimale Abstimmung auf den konkreten Anwendungsfall möglich wird. Insbesondere kann durch geschickte Anordnung vermieden werden, dass die Hilfsreflektoren sich gegenseitig stören oder den Strahlungsbereich des Hauptreflektors abschatten.However, other, more complicated embodiments are also conceivable. It is thus possible for the focal point distances on the focal point axes assigned to the individual auxiliary reflectors to be at least partially different. The reflector surfaces of the individual auxiliary reflectors can therefore be based on differently curved rotational hyperboloids, the auxiliary reflectors can thus be arranged at different distances from the focal point of the parabolic main reflector. Furthermore, the inclinations of the focal axes can be different from the axis of the main reflector. Overall, there are many possible variations in the arrangement of the auxiliary reflectors, so that an optimal adaptation to the specific application is possible. In particular, a clever arrangement can prevent the auxiliary reflectors from interfering with one another or shadowing the radiation area of the main reflector.
Andererseits kann auch zugelassen werden, dass benachbarte Hilfreflektoren sich gegenseitig teilweise überlappen. Dann muss nur dafür Sorge getragen werden, dass diese benachbarten Hilfsreflektoren für jeweils orthogonale Polarisationsrichtungen oder unterschiedliche Frequenzbereiche selektiv sind. Im ersteren Fall können gitterartige, aus steifen oder gespannten parallelen Metallbändern bestehende Strukturen verwendet werden. Sind etwa drei Hilfsreflektoren vorgesehen, von denen der mittlere an seinen beiden gegenüberliegenden Rändern jeweils von einem der beiden äusseren überlappt wird, so können letztere beispielsweise für horizontale, ersterer für vertikale Polarisation ausgelegt sein.On the other hand, it can also be allowed that neighboring auxiliary reflectors partially overlap each other. Then only care must be taken to ensure that these neighboring auxiliary reflectors are selective for orthogonal polarization directions or different frequency ranges. In the former case, grid-like structures consisting of rigid or tensioned parallel metal strips can be used. If about three auxiliary reflectors are provided, of which the middle one at its two opposite edges is overlapped by one of the two outer edges, the latter can be designed, for example, for horizontal, the former for vertical polarization.
Die einander überlappenden Randbereiche der Hilfsreflektoren wirken dann nicht störend auf die gewünschte Strahlungsreflektion. In ähnlicher Weise können an sich bekannte frequenzselektive Reflektoren als sich gegenseitig teilweise überlappende Hilfsreflektoren eingesetzt werden.The overlapping edge areas of the auxiliary reflectors then do not interfere with the desired radiation reflection. In a similar manner, frequency-selective reflectors known per se can be used as auxiliary reflectors which partially overlap one another.
Die Erfindung schliesst noch den Fall ein, dass einer der aus der Unterteilung der Gesamtheit der Einzelstrahler hervorgehenden Strahlergruppen kein Hilfsreflektor zugeordnet, diese Strahlergruppe vielmehr am Brennpunkt des parabolischen Hauptreflektors angeordnet ist und diesen direkt anstrahlt.The invention also includes the case that one of the radiator groups resulting from the subdivision of the totality of the individual radiators is not assigned an auxiliary reflector, rather this radiator group is arranged at the focal point of the parabolic main reflector and illuminates it directly.
Claims (8)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823204029 DE3204029A1 (en) | 1982-02-05 | 1982-02-05 | MULTI-REFLECTOR ANTENNA |
| DE3204029 | 1982-02-05 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0086399A1 EP0086399A1 (en) | 1983-08-24 |
| EP0086399B1 true EP0086399B1 (en) | 1988-06-22 |
Family
ID=6154924
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP83100957A Expired EP0086399B1 (en) | 1982-02-05 | 1983-02-02 | Aerial with several reflectors |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0086399B1 (en) |
| DE (1) | DE3204029A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3631735A1 (en) * | 1986-09-18 | 1988-04-07 | Messerschmitt Boelkow Blohm | MESSAGE TRANSFER DEVICE FOR SPACE VEHICLES |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0028018A1 (en) * | 1979-10-24 | 1981-05-06 | Western Electric Company, Incorporated | An improved phased array antenna system |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3414904A (en) * | 1966-05-16 | 1968-12-03 | Hughes Aircraft Co | Multiple reflector antenna |
| US3914768A (en) * | 1974-01-31 | 1975-10-21 | Bell Telephone Labor Inc | Multiple-beam Cassegrainian antenna |
| US3953858A (en) * | 1975-05-30 | 1976-04-27 | Bell Telephone Laboratories, Incorporated | Multiple beam microwave apparatus |
| US4090203A (en) * | 1975-09-29 | 1978-05-16 | Trw Inc. | Low sidelobe antenna system employing plural spaced feeds with amplitude control |
| US4236161A (en) * | 1978-09-18 | 1980-11-25 | Bell Telephone Laboratories, Incorporated | Array feed for offset satellite antenna |
| US4298877A (en) * | 1979-01-26 | 1981-11-03 | Solar Energy Technology, Inc. | Offset-fed multi-beam tracking antenna system utilizing especially shaped reflector surfaces |
-
1982
- 1982-02-05 DE DE19823204029 patent/DE3204029A1/en not_active Ceased
-
1983
- 1983-02-02 EP EP83100957A patent/EP0086399B1/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0028018A1 (en) * | 1979-10-24 | 1981-05-06 | Western Electric Company, Incorporated | An improved phased array antenna system |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0086399A1 (en) | 1983-08-24 |
| DE3204029A1 (en) | 1983-08-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| DE2503594C2 (en) | ||
| DE3879383T2 (en) | DETERMINISTALLY DISTINATED, PHASE CONTROLLED ANTENNA GROUP WITH RADIATION OPENINGS. | |
| EP2735055B1 (en) | Reflector antenna for a synthetic aperture radar | |
| DE2311439C2 (en) | Two reflector antenna rotatable about an azimuth axis and an elevation axis | |
| DE3536581C2 (en) | ||
| DE2505375A1 (en) | ANTENNA SYSTEM CONSISTS OF A PARABOLIC MIRROR AND AN EXCITER | |
| DE4026432A1 (en) | PLANAR ANTENNA | |
| DE69208706T2 (en) | Payload architecture in space technology | |
| DE60107939T2 (en) | REFLECTOR ANTENNA WITH COMMON APERTURE AND IMPROVED FEEDING DRAFT | |
| DE69611600T2 (en) | MULTIFUNCTIONAL CELLULAR TELEVISION SYSTEM WITH LOW PERFORMANCE | |
| EP0028836B1 (en) | Antenna arrangement for an omnidirectional search radar for target location with height detection | |
| DE2246650A1 (en) | APLANATIC HIGH FREQUENCY ANTENNA | |
| DE2058550C3 (en) | Antenna with a spherical main reflector | |
| DE2610506A1 (en) | ANTENNA | |
| DE2162068A1 (en) | Cylinder antenna | |
| DE60204946T2 (en) | REFLECTOR ANTENNA | |
| DE69212378T2 (en) | Antenna with shaped radiation beam and high gain | |
| DE60013792T2 (en) | Limited field-of-view antenna for space applications | |
| EP0086399B1 (en) | Aerial with several reflectors | |
| DE2319731A1 (en) | ECCENTRIC CASSEGRAIN ANTENNA | |
| DE3820920C2 (en) | ||
| DE60120909T2 (en) | Double reflector antenna with deflector | |
| DE1766019A1 (en) | High-frequency multi-beam antenna for the direction finding of an area spanning several octaves | |
| DE69830199T2 (en) | ANTENNA ARRANGEMENT AND METHOD CONNECTED WITH SUCH AN ARRANGEMENT | |
| DE2650603A1 (en) | Radiation supplied phase controlled group of radiators - consists of collector and emitter radiators distributed on surface of truncated cone |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| AK | Designated contracting states |
Designated state(s): FR GB IT SE |
|
| 17P | Request for examination filed |
Effective date: 19840221 |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): FR GB IT SE |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: SE Effective date: 19880630 |
|
| GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) | ||
| ET | Fr: translation filed | ||
| ITF | It: translation for a ep patent filed | ||
| PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
| 26N | No opposition filed | ||
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19900131 Year of fee payment: 8 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19900209 Year of fee payment: 8 |
|
| ITTA | It: last paid annual fee | ||
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19910202 |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee | ||
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Effective date: 19911031 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST |