EP0164466B1 - Antenne multifaisceau à rendement élevé - Google Patents

Antenne multifaisceau à rendement élevé Download PDF

Info

Publication number
EP0164466B1
EP0164466B1 EP19840304016 EP84304016A EP0164466B1 EP 0164466 B1 EP0164466 B1 EP 0164466B1 EP 19840304016 EP19840304016 EP 19840304016 EP 84304016 A EP84304016 A EP 84304016A EP 0164466 B1 EP0164466 B1 EP 0164466B1
Authority
EP
European Patent Office
Prior art keywords
reflector
antenna
beams
degree
divergency
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
Application number
EP19840304016
Other languages
German (de)
English (en)
Other versions
EP0164466A1 (fr
Inventor
Paul Gates Ingerson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Northrop Grumman Space and Mission Systems Corp
Original Assignee
TRW Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TRW Inc filed Critical TRW Inc
Priority to DE8484304016T priority Critical patent/DE3484684D1/de
Priority to EP19840304016 priority patent/EP0164466B1/fr
Publication of EP0164466A1 publication Critical patent/EP0164466A1/fr
Application granted granted Critical
Publication of EP0164466B1 publication Critical patent/EP0164466B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/007—Antennas or antenna systems providing at least two radiating patterns using two or more primary active elements in the focal region of a focusing device
    • 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
    • H01Q19/12—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 wherein the surfaces are concave
    • H01Q19/17—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 wherein the surfaces are concave the primary radiating source comprising two or more radiating elements

Definitions

  • This invention relates generally to antenna systems, and more particularly, to antenna systems used for communication to and from satellites.
  • satellite communication systems there is a need to provide high-gain independent beams covering an angular region of space.
  • the peak gains that one can achieve in the multiple beams are typically much lower that one can achieve using a single optimum antenna feed horn at the focal region of the lens or reflector.
  • the peak gain of each of the multiple beams may be 3 dB or more lower than that of an optimum single-feed antenna beam.
  • a multibeam antenna system on such a satellite has to to provide contiguous coverage of practically one hemisphere of the earth.
  • the half-angle subtended by the earth at the position of a synchronous satellite is approximately 8.68 degrees.
  • a desirable compromise is to provide contiguous coverage at a power of at least half the peak power of each beam.
  • HPBW half-power beamwidth
  • the HPBW is the angular width of the beam measured at a point where the gain is one-half of the peak gain at the center of the beam. If adjacent beams, as defined by their half-power beamwidths, overlap sufficiently to leave no gaps, the array of beams is said to provide contiguous coverage at the -3 dB level, or half-power level, or better.
  • a conventional high-frequency antenna system includes an antenna feed horn through which transmitted signals are directed, and a focusing element, such as a reflector or lens, to focus the energy radiated from the feed horn into a beam. If some of the energy from the feed horn does not impinge on the focusing element, the system is clearly not operating at maximum efficiency. The gain of the antenna system is maximized when the primary radiation from the feed horn is practically all incident on the focusing element, and none "spills over" the edges of the element.
  • the feed horn diameter to maximize gain is substantially larger than the feed horn diameter that will permit close packing, i.e. with coverage to the -3 dB level, in a single conventional focusing reflector or lens. Accordingly, horn aperture sizes that yield maximum gain lead to beam separations much larger than one half-power beamwidth.
  • a typical conventional reflector and lens system is disclosed in US-A-4236161.
  • the arrangement illustrated in this document is a Cassegranian antenna system having a main reflector and subreflector for producing a plurality of secondary beams of radiation from an equal plurality of primary beams of radiation impinging on the subreflector and a plurality of antenna feed horns positioned in an array to produce the plurality of primary radiation beams.
  • the feed horns are disposed on the focal surface of the reflector and subreflector and are arranged in clusters such that the beams of energy from the clusters are launched in plural frequency sub bands at one or both orthogonal polarisations, thus providing discrimination between the beams.
  • the only way to achieve a desired beam overlap for a given beamwidth is to vary the included angle of the lens or reflector of the system.
  • the lens or reflector included angle has to be reduced below its optimum value, and then there is "spillover" loss and lowered efficiency.
  • a possible solution to this problem is to provide multiple lenses or reflectors. Then each lens or reflector does not have to accommodate multiple beams in such a closely spaced relationship. However, the multiple lenses or reflectors introduce additional complexity, and must be maintained in very precise alignment for good results. It will be appreciated from the foregoing that there is a need for a single-reflector or single-lens multibeam antenna system capable of providing closely packed, secondary beams, but without degradation of the efficiency of the system.
  • the present invention fulfills this need.
  • the present invention resides in a multibeam antenna system, comprising: a single reflector or lens element for producing a plurality of secondary beams of radiation from an equal plurality of primary beams of radiation impinging on the reflector or lens element; and a plurality of antenna feed horns positioned in an array to produce the plurality of primary radiation beams; characterised in that the reflector or lens element and the antenna feed horns are configured to produce the secondary beams, as diverging beams the degree of divergency and the aperture size of the feed horns being selected to maximize the gain of the antenna system and to produce the secondary radiation beams with a desired beamwidth at a specified power level; and the diameter and focal distances of the reflector or lens element are scaled up to provide an overlap of the secondary radiation beams that produces contiguous coverage of an area by the secondary radiation beams at the specified power level, while maintaining the degree of divergency and the aperture size of the feed horns to preserve the maximized gain of the antenna system and the beamwidth of the secondary radiation beams.
  • the invention includes a related method for adapting an antenna system to provide a desired angular beam width and a desired beam pattern overlap.
  • the present invention also provides a method of adapting a multibeam antenna system to provide desired beam characteristics without significant loss of gain or efficiency, the method comprising the steps of: selecting a plurality of antenna feed horns engendering primary beams positioned in an array and a single antenna reflector, the antenna reflector and the antenna feed horns being configured to produce diverging secondary beams; selecting the degree of divergency and the aperture size of the feed horns to maximize the gain of the antenna system and to produce secondary radiation beams that diverge from the reflector with a desired angular beamwidth at a specified power level; and scaling the diameter and focal distances the reflector to adjust the secondary beam overlap to produce contiguous coverage of an area by the secondary radiation beams at the specified power level, while maintaining the degree of divergency and the aperture size of the feed horns to preserve the maximised gain of the antenna system and the beamwidth of
  • the angular beamwidth may be varied independently of the diameter of the antenna aperture.
  • the antenna aperture element may be a reflector or lens. More specifically, there are two basic configurations that fall into the "non-focused" category. It is convenient to define these in terms of reflector structures, although it will be appreciated that there are equivalent lens structures that perform in an analogous manner.
  • Existing antenna reflectors are of a parabolic or paraboloid shape and produce a nearly parallel beam from a diverging beam placed at the focus of the parabola.
  • One embodiment of the invention uses instead a hyperbolic or hyperboloid reflector, which produces a diverging beam instead of a parallel beam.
  • the angular beamwidth of the secondary beam from the hyperboloid reflector is a function of the magnification factor of the reflector, and is essentially independent of the reflector diameter. Independent control of the degree of beam pattern overlap is obtained by varying the diameter of lens or reflector while maintaining the same proportions, and hence the same magnification factor and beamwidth.
  • a close approximation to the hyperbolic reflector is obtained by instead using an axially defocused parabolic reflector to obtain the necessary divergent secondary beams from the reflector.
  • the beamwidth is controllable, in this case by varying the degree of defocusing, and the degree of beam pattern overlap can be varied by changing the reflector diameter without changing its proportions.
  • the present invention represents a significant advance in the field of multibeam antennas.
  • the invention provides a multibeam antenna system with a single antenna aperture, which may be a reflector or a lens, having the desirable characteristics of high gain and efficiency over a wide range of feed horn sizes and feed-to-feed separations.
  • the antenna system of the invention can be easily designed to provide any of a wide range of beam-to-beam separations or crossover levels, and to provide a beamwidth that is selectable independently of the antenna aperture.
  • the system allows for efficient and simple sidelobe control, to provide for minimal out-of-beam interference.
  • the present invention is concerned with multibeam antennas.
  • Such antennas are useful in a variety of applications, including some satellite and ground-based communications systems, and monopulse tracking systems.
  • the antenna of the invention is disclosed in relation to a satellite communication system requiring a closely packed array of multiple beams of high gain and high efficiency.
  • the antenna of the invention will be discussed in terms of its function as a transmitter, merely because the concepts involved can usually be more easily understood by consideration of the transmitter action. It will be appreciated, however, that similar but reciprocal considerations apply to the antenna system in its role as a receiver.
  • FIG. 1 shows the positions of thirty-seven antenna beams, shown as small circles, in relation to the earth, indicated by reference numeral 12, as viewed from the position of a synchronously orbiting satellite.
  • the earth as viewed from such a satellite subtends a half-angle of approximately 8.68 degrees.
  • the geometrical relationships are such that, to provide contiguous coverage of the visible earth surface at a gain of at least half the peak beam gain, the multiple beams must have a half-power beamwidth of approximately 3.3 degrees and an angular center-to-center separation of approximately 2.9 degrees.
  • the half-power beamwidth is the angular width of a beam taken at a circular line defining a constant gain of one-half the peak gain of the beam.
  • FIG. 2 shows the gain patterns for ten of the beams, indicated by letters a-j in both FIGS. 1 and 2. It will be observed that, in the regions where the beam patterns overlap, the curves defining a -3 dB gain always overlap to such a degree that no region between beam patterns is exposed to a gain that is more than 3 dB below the peak.
  • This diagram represents the desired coverage to be provided by an illustrative antenna system. However, before the invention can be described in detail there should be an understanding of the limitations of focused antenna systems of the prior art.
  • FIG. 6a shows a paraboloid reflector 16, receiving radiation from a focal point 18.
  • a parabola has associated with it a focal point at which parallel beams impinging on its surface will converge.
  • FIG. 6b shows an offset paraboloid reflector 16' on which primary radiation impinges from a focal point 18', resulting in a parallel beam 20'.
  • a lens 22 may be used to produce a parallel beam 24 from a source of radiation located at a focal point 26.
  • the size of the reflector and lens elements can have a significant influence on the behavior of the antenna system. For example, although a nearly parallel beam of light may be obtained from a parabolic mirror, generation of a parallel beam at radio frequencies is a practical impossibility. Because the diameter of the reflector is not infinitely larger than the wavelength of the radiation, diffraction effects result in a slightly diverging beam. Moreover, the angular beamwidth of the reflected beam is highly dependent on the diameter of the reflector.
  • a single antenna feed horn is used in conjunction with a reflector, such as the one in FIG. 6b, there is an optimum combination of reflector included angle and feed horn size needed to produce maximum gain.
  • a wider primary anglular beamwidth results.
  • the feed horn size is increased, the resulting primary beam has a correspondingly smaller angle. It will be apparent, then, that for a given size of reflector, the feed horn should be sized to produce a primary beam that practically fills the reflector aperture. Any larger primary angle will result in "spillover" loss of the energy not incident on the reflector. Any smaller angle also results in losses.
  • An alternative way to optimize a single beam is to keep the feed horn size constant and vary the reflector included angle, i.e. the angle subtended at the focus of the reflector by the reflector diameter. This is shown graphically in FIG. 3, which plots the variation of gain as a function of reflector included angle.
  • the feed horn diameter was fixed at one inch, corresponding to approximately four wavelengths at a frequency of 44.5 gigahertz (GHz), and the half-power beamwidth was kept nearly constant at 3.3 degrees.
  • Beamwidth control for a parabolic reflector is obtained by varying the diameter. Because of the diffraction effects mentioned earlier, the angular beamwidth varies inversely with the diameter of the reflector.
  • the included angle of the reflector can be varied by changing the focal length of the reflector. As the focal length is increased, the included angle is decreased. As FIG. 3 shows, the gain peaks at an included angle of approximately 32 degrees. At smaller included angles, some of the primary radiation spills over the edge of the reflector and the gain and efficiency are diminished.
  • FIG. 4 shows the same thirty-seven beam positions divided into three groups, so that in no group are there any two beams that were in adjacent positions in the original array.
  • the feed horn arrangements for the groups labelled a, b and c are shown in FIGS. 5a-5c, respectively. Since any two adjacent feeds in one of the groups now produce two more widely spaced beams in the composite array, the included angle for each reflector can be much greater than the 15-degree value needed to produce a -3 dB crossover for adjacent beams.
  • the closest spacing that occurs between beams produced by adjacent feed horns in the same group is about 1.73 times the half-power beam width. This larger separation allows the included angle to be about 24 degrees, and results in a spillover loss of less than 1 dB.
  • the reflector diameter for each of the three reflectors is about five inches, or close to twenty wavelengths.
  • the cost and alignment problems associated with multiple reflector apertures are substantial.
  • the edge illumination in the system is relatively high and there is no simple way to control the beam sidelobe levels.
  • FIGS. 7a and 7b show two non-focused antenna apertures that can be used in practicing the invention.
  • FIG. 7a shows a hyperboloid reflector 30 receiving a primary beam from a point 32 and reflecting a diverging secondary beam 34, which has a spherical wavefront 36 centered at a focal point 38 located behind the reflector 30.
  • FIG. 7b shows an equivalent lens structure, including a diverging lens 40 receiving primary radiation from a point 42, resulting in a diverging beam 44.
  • the diverging beam has a spherical wavefront 46 centered at a virtual source point 48 located on the same side of the lens as the primary source 42.
  • the magnification is defined as the ratio of the primary beam angle at point 32 (FIG. 7a) to the resulting secondary beam angle measured at point 38. For example, if the magnification is 10 the primary beam angle would have to be 33 degrees to produce a desired half-power beamwidth of 3.3 degrees.
  • the relationship between secondary half-power beamwidth and feed horn size is plotted in FIG. 11 for various magnifications. For relatively low magnifications, up to 10 or so, the secondary HPBW first decreases as the feed horn size is increased. It will be recalled that increasing the feed horn size provides a smaller primary beamwidth. This results in a correspondingly smaller secondary HPBW.
  • the primary beam becomes limited to a region quite close to the center of the reflector.
  • the resulting secondary beam is still divergent, the magnification of the reflector has less effect and the curves for the different magnifications tend to merge into one.
  • the behavior is practically that of a parabolic reflector.
  • the secondary beam is practically parallel for low feed horn sizes. Then, as the feed horn size is increased the diameter of the beam is reduced and diffraction effects reduce the degree of parallelism of the beam. In other words, the secondary HPBW increases as the horn size is increased. This curve also merges with the others in the region of a 7-10 wavelength horn size.
  • the most important aspect of FIG. 11 is that there is a range of feed horn sizes, up to about 5 wavelengths in diameter, over which the secondary HPBW is solely a function of magnification.
  • a secondary HPBW of 3.3 degrees by selecting a horn size of four wavelengths and a reflector with a magnification of 5.75.
  • a desired sidelobe performance can be first optimized, to provide a suitable degree of isolation between adjacent beams. Then, assuming that the magnification and feed horn design have been fixed to provide a desired secondary HPBW, the desired crossover level can be selected by adjusting the physical size of the reflector.
  • the reflector can be scaled up in size. Its focal distances are also scaled up, but their ratio, and so also the magnification, remain unchanged. However, the increase in focal length results in a crossover at the desired gain level.
  • the focal length which determines the spacing between the reflector and the feed horns, is also scaled up. If the reflector is initially optimized for maximum gain, i.e. if the primary beam energy is almost totally incident on the reflector, this optimization will still hold good after scaling of the reflector. Thus, the high gain and efficiency of the system will be maintained even if the degree of beam overlap is adjusted. Similarly, the optimization is not affected when the magnification of the reflector is changed to select a desired angular beamwidth.
  • the results obtained using the hyperbolic reflector characteristics shown in FIG. 11 can be closely approximated by defocusing a parabolic reflector.
  • defocusing may be effected by axial displacement of the feed horns supplying the primary beam to the reflector 50.
  • the effect is to produce a divergent beam 52, which is broadened in accordance with the relationship plotted in FIG. 9.
  • FIG. 9 shows is that, at the expense of a loss in gain, which is inherent in any divergent beam, the HPBW can be broadened substantially. This is equivalent to raising the lower curve in FIG. 11 by the HPBW broadening factor. By this means one can obtain the desired 3.3 degree HPBW from a defocused parabolic reflector.
  • the present invention represents a significant advance in the field of multibeam antennas.
  • the invention provides a novel technique for independently obtaining a desired angular beamwidth and beam spacing without loss of gain or antenna efficiency.

Landscapes

  • Aerials With Secondary Devices (AREA)

Claims (7)

  1. Système d'antenne multifaisceau comprenant:
    un unique élément réflecteur ou de lentille (30, 40, 50) pour produire plusieurs faisceaux de rayonnement secondaires à partir d'un nombre égal de faisceaux de rayonnement primaires venant heurter l'élément réflecteur ou de lentille (30, 40, 50) et
    plusieurs cornets d'alimentation d'antenne disposés en réseau pour produire plusieurs faisceaux de rayonnement primaires,
    caractérisé en ce que
    l'élément réflecteur ou de lentille (30, 40, 50) et les cornets d'alimentation d'antenne sont configurés pour produire les faisceaux secondaires sous forme de faisceaux divergents. le degré de divergence et la dimension de l'ouverture des cornets d'alimentation étant choisis pour rendre le gain du système d'antenne maximal et pour produire les faisceaux de rayonnement secondaires selon la largeur de faisceau désirée pour un niveau de puissance spécifié; et
    les diamètres et les distances focales de l'élément réflecteur ou de lentille (30, 40, 50) sont échelonnés pour déterminer un chevauchement des faisceaux de rayonnement secondaires qui produit une couverture contiguë d'une région par les faisceaux de rayonnement secondaires au niveau de puissance spécifié, tout en maintenant le degré de divergence et la dimension d'ouverture des cornets d'alimentation pour conserver le gain rendu maximal du système d'antenne et la largeur de faisceau des faisceaux de rayonnement secondaires.
  2. Système d'antenne multifaisceau selon la revendication 1, dans lequel:
    l'élément d'ouverture est un réflecteur parabolique (50);
    le degré de divergence est choisi en déplaçant axialement les cornets d'alimentation d'antenne par rapport au point focal du réflecteur parabolique; et
    le degré de divergence est maintenu pendant qu'est ajusté le diamètre de l'élément d'ouverture en ajustant de façon proportionnelle la longueur focale du réflecteur parabolique quand le diamètre du réflecteur parabolique est ajusté.
  3. Système d'antenne multifaisceau selon la revendication 1, dans lequel:
    l'élément réflecteur ou de lentille est un réflecteur hyperbolique (30);
    le degré de divergence est choisi en ajustant le facteur d'amplification du réflecteur hyperbolique; et
    le degré de divergence est maintenu pendant l'ajustage du diamètre de l'élément d'ouverture en ajustant de façon proportionnelle la longueur focale du réflecteur hyperbolique quand le diamètre du réflecteur hyperbolique est ajusté.
  4. Système d'antenne multifaisceau selon la revendication 1, dans lequel:
    l'élément réflecteur ou de lentille est une lentille divergente (40).
  5. Procédé pour adapter un système d'antenne multifaisceau pour obtenir des caractéristiques de faisceau désirées sans perte importante de gain ou de rendement, le procédé comprenant les étapes consistant à:
    sélectionner plusieurs cornets d'alimentation d'antenne engendrant des faisceaux primaires disposés en réseau et un unique réflecteur d'antenne, le réflecteur d'antenne et les cornets d'alimentation d'antenne étant configurés pour produire des faisceaux de rayonnement secondaires divergents;
    sélectionner le degré de divergence et la dimension d'ouverture des cornets d'alimentation pour porter au maximum le gain du système d'antenne et pour produire des faisceaux de rayonnement secondaires qui divergent à partir du réflecteur selon une largeur angulaire de faisceau désirée pour un niveau de puissance spécifié; et
    échelonner le diamètre et les distances focales du réflecteur pour ajuster le chevauchement des faisceaux secondaires et produire une couverture contiguë d'une région par les faisceaux de rayonnement secondaires au niveau de puissance spécifié, tout en maintenant le degré de divergence et la dimension d'ouverture des cornets d'alimentation pour conserver le gain porté au maximum du système d'antenne et la largeur de faisceau des faisceaux de rayonnement secondaires.
  6. Procédé selon la revendication 5, dans lequel:
    le réflecteur d'antenne est un réflecteur hyperbolique (30);
    le degré de divergence est sélectionné en ajustant le facteur d'amplification du réflecteur hyperbolique; et
    le degré de divergence est maintenu pendant l'ajustage du diamètre du réflecteur d'antenne en ajustant de façon proportionnelle la longueur focale du réflecteur hyperbolique quand le diamètre du réflecteur hyperbolique est ajusté.
  7. Procédé selon la revendication 5, dans lequel:
    le réflecteur d'antenne est un réflecteur parabolique (50);
    le degré de divergence est sélectionné en déplaçant axialement les cornets d'alimentation d'antenne par rapport au point focal du réflecteur parabolique; et
    le degré de divergence est maintenu pendant l'ajustage du diamètre du réflecteur d'antenne en ajustant de façon proportionnelle la longueur focale du réflecteur parabolique quand le diamètre du réflecteur parabolique est ajusté.
EP19840304016 1984-06-14 1984-06-14 Antenne multifaisceau à rendement élevé Expired EP0164466B1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE8484304016T DE3484684D1 (de) 1984-06-14 1984-06-14 Mehrstrahlantenne mit hohem wirkungsgrad.
EP19840304016 EP0164466B1 (fr) 1984-06-14 1984-06-14 Antenne multifaisceau à rendement élevé

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19840304016 EP0164466B1 (fr) 1984-06-14 1984-06-14 Antenne multifaisceau à rendement élevé

Publications (2)

Publication Number Publication Date
EP0164466A1 EP0164466A1 (fr) 1985-12-18
EP0164466B1 true EP0164466B1 (fr) 1991-06-05

Family

ID=8192663

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840304016 Expired EP0164466B1 (fr) 1984-06-14 1984-06-14 Antenne multifaisceau à rendement élevé

Country Status (2)

Country Link
EP (1) EP0164466B1 (fr)
DE (1) DE3484684D1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5206658A (en) * 1990-10-31 1993-04-27 Rockwell International Corporation Multiple beam antenna system
FR2684809B1 (fr) * 1991-12-09 1994-01-21 Alcatel Espace Antenne passive multifaisceaux a reflecteur(s) conforme (s).
IT1272984B (it) * 1994-05-17 1997-07-01 Space Eng Srl Antenna a riflettore o a lente, a fasci sagomati o a scansione di fascio
US5734345A (en) * 1996-04-23 1998-03-31 Trw Inc. Antenna system for controlling and redirecting communications beams

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4090203A (en) * 1975-09-29 1978-05-16 Trw Inc. Low sidelobe antenna system employing plural spaced feeds with amplitude control
US4201992A (en) * 1978-04-20 1980-05-06 Communications Satellite Corporation Multibeam communications satellite
US4236161A (en) * 1978-09-18 1980-11-25 Bell Telephone Laboratories, Incorporated Array feed for offset satellite antenna

Also Published As

Publication number Publication date
DE3484684D1 (de) 1991-07-11
EP0164466A1 (fr) 1985-12-18

Similar Documents

Publication Publication Date Title
US4855751A (en) High-efficiency multibeam antenna
US4618867A (en) Scanning beam antenna with linear array feed
US3835469A (en) Optical limited scan antenna system
US6396453B2 (en) High performance multimode horn
US7394436B2 (en) Multi-beam and multi-band antenna system for communication satellites
US6366256B1 (en) Multi-beam reflector antenna system with a simple beamforming network
Rotman Wide-angle scanning with microwave double-layer pillboxes
US4482897A (en) Multibeam segmented reflector antennas
US10566698B2 (en) Multifocal phased array fed reflector antenna
EP0028018B1 (fr) Système d'antennes du type à réseau à déphasage
US7522116B2 (en) Multibeam antenna
US7161549B1 (en) Single-aperture antenna system for producing multiple beams
US4145695A (en) Launcher reflectors for correcting for astigmatism in off-axis fed reflector antennas
JP2632457B2 (ja) 多重ビームアンテナシステム
EP0248886B1 (fr) Antenne optique a balayage limite de haut rendement
US6323815B1 (en) Antenna configuration for low and medium earth orbit satellites
WO2019170541A1 (fr) Réseaux de plans focaux à balayage extrême utilisant un concept à double réflecteur avec éclairage de réseau uniforme
EP0164466B1 (fr) Antenne multifaisceau à rendement élevé
EP1207584B1 (fr) Antenne à réflecteur intégrée à deux faisceaux
CN110739547A (zh) 一种卡塞格伦天线
US6424310B1 (en) Compact folded optics antenna system for providing adjacent, high gain antenna beams
US6882323B2 (en) Multi-beam antenna system with shaped reflector for generating flat beams
EP1184939B1 (fr) Antenne à réflecteur à grilles
GB2262387A (en) Multibeam antenna
US10777903B2 (en) Multi-beam antenna (variants)

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

AK Designated contracting states

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19860520

17Q First examination report despatched

Effective date: 19880218

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB NL

REF Corresponds to:

Ref document number: 3484684

Country of ref document: DE

Date of ref document: 19910711

ET Fr: translation 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: NL

Payment date: 19980324

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19980505

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19980603

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19980625

Year of fee payment: 15

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990614

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19990630

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000101

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19990614

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20000101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20000503

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST