EP0043689A2 - Beam waveguide feed for antenna - Google Patents
Beam waveguide feed for antenna Download PDFInfo
- Publication number
- EP0043689A2 EP0043689A2 EP81302955A EP81302955A EP0043689A2 EP 0043689 A2 EP0043689 A2 EP 0043689A2 EP 81302955 A EP81302955 A EP 81302955A EP 81302955 A EP81302955 A EP 81302955A EP 0043689 A2 EP0043689 A2 EP 0043689A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- reflector
- waveguide
- horn
- sub
- concave
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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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
- H01Q19/191—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 wherein the primary active element uses one or more deflecting surfaces, e.g. beam waveguide feeds
Definitions
- This invention relates to apparatus for feeding electromagnetic signals, particularly in the microwave and radio frequency areas of the spectrum between, on the one hand a reflector belonging to an antenna and, on the other hand, transmitting and/or receiving equipment for delivering signals to or receiving them from the antenna.
- FIG. 1 A typical known apparatus of the type described above is shown very schematically in Figure 1 of the accompanying drawings.
- a building 1 which houses microwave signal detecting and generating equipment lA.
- Microwave energy passes from lA along a short waveguide 2 which terminates in a large corrugated radiating horn 3. This emits a beam 4 of radiation which diverges from point 5 inside the mouth of the horn with an angle of divergance (a).
- the diverging beam 4 enters a beam waveguide 6 mounted on a support structure 7 which has wheels 8 riding on a circular track 9.
- the support structure 7 and the beam waveguide 6 can thus be rotated about a.vertical axis X-X.
- the means for effecting such rotation is not illustrated in the drawing.
- the beam waveguide 6 has a lower tubular portion containing a flat reflector 10 from which the diverging beam 4 is reflected to a parabolic reflector 11.
- the latter has its focus at or near point 5 and therefore produces an essentially parallel beam which is directed to another parabolic reflector 12.
- the reflector 12 brings the beam to a focus at point 13 after reflection from a flat reflector 14.
- the beam now diverging again, is scattered from a sub-reflector 15 to a main reflector 16 from where the signals are transmitted into the atmosphere or into space if the apparatus is located in an extra terrestrial position.
- the main reflector 16 has support arms 17 pivotted about a horizontal axis Y-Y to the support structure 7.
- the beam waveguide 6 is divided as indicated at 6A into upper and lower parts so as to enable the upper part to rotate with the reflector 16 about the axis Y-Y.
- the means for rotating the reflector 16 about the horizontal axis Y-Y is not shown in the drawing. By selecting the appropriate positions of rotation about the axes X-X and Y-Y the reflector 16 can be made to point in any desired direction.
- the horn 3 needs to radiate most of the energy within a narrow angle (a), so that an acceptable proportion of the energy is incident upon reflectors 10 and 11.
- a the horn must be very large, possibly several metres high.
- the horn is therefore very expensive, particularly if, as is usually the case, the horn is internally corrugated along its entire length.
- This invention provides apparatus for transmitting or receiving electromagnetic signals comprising a path for the signals extending: from a signal generator or detector to a member located in front of a concave reflector; from the said member to the concave reflector; from the concave reflector, past opposite sides of the said member to a beam waveguide; and from the beam waveguide to a main reflector.
- the concave reflector provided by this invention enables a widely diverging beam, from for example a small horn, to be converted into a beam having a smaller angle of divergance, such as would be obtained from a large horn.
- the cost of the conventional large horn is thus substantially eliminated at the expense of a relatively inexpensive concave reflector.
- the concave reflector can be designed to give a beam having as small an angle of divergance as may be required or even a parallel beam or a converging beam. The invention therefore makes it possible in cases to eliminate the need for concave reflectors in the beam waveguide thus further reducing the cost of the system.
- the said "member” can be a relatively small horn positioned in front of the concave reflector and directed towards the latter.
- a horn requires a waveguide feed which, because of its necessary cross- sectional area, obstructs to a significant.extent the path between the concave reflector and the beam waveguide.
- the said "member” be a sub-reflector positioned axially in front of the concave reflector and arranged so that the said path passes through an aperture in the centre of the concave reflector between the sub-reflector and a horn or equivalent member located behind the concave reflector.
- a sub-reflector as described above can be supported on relatively slender supports which do not present any significant obstacle to the passage of radiation along the aforementioned path.
- this apparatus has components 1,1A,2,6,7,8,9,10,11,12,14,15,16 and 17 identical to those shown in Figure 1. Of these only components 10 and 11 and part of component 6 are shown in Figure 2.
- the large horn 3 of Figure 1 is replaced, in Figure 2, by a small horn 18 which emits, or receives, a beam 19 whose angle of divergance, or convergance, is denoted by the letter (b). This angle (b) is much greater than the corresponding angle (a) of Figure 1 because of the smaller horn size.
- the beam 19 passes through a central aperture in a concave reflector 20 behind which the horn 18 is situated.
- The,beam is then reflected from a sub-reflector 21 onto the front of the concave reflector 20.
- the concave reflector 20 is elliptical in section having one focus at the point 5, which is the same as the point 5 shown in Figure l; and its other focus at a point 5A.
- the convex reflector 2l is hyperbolic in section, having one focus at 5A and its other focus at 5B inside the mouth of the horn 18. Accordingly, the beam eflected from the reflector 20 is brought to a focus at point 5.
- the angle of convergance and divergance at point 5 is chosen to be equal to the angle (a) of Figure 1 so that after passing point 5 the beam behaves exactly as described with reference to Figure 1.
- the apparatus depicted in Figure 2 can thus be used as a direct replacement for the large horn 3 of Figure 1 without the need arising for any other modifications to the equipment.
- Figure 3 shows an apparatus similar to that of Figure 2 but modified by the replacement of the elliptical reflector 20 by a parabolic reflector 22 having its focus at the point 5A. This produces a parallel beam which is directed into the beam waveguide 6. Since the beam is parallel there is no need for curved reflectors in the beam waveguide. Thus the reflectors 11 and 12 of Figure 1 can be replaced by planar reflectors such as shown at 11A.
- the sub-reflector 21 is preferably shaped so that it directs no radiation, or a relatively low intensity of radiation to the central portion of the reflector 22. This is illustrated in Figure 4 where regions of the beam having maximum intensity values are shown by the shaded areas. From Figure 4 it is apparent that the sub-reflector 21 is effective to shape the beam 4 into an annular configuration which is incident on the part 23 of the reflector 22 but not to a substantial extent on the central part of this reflector. As a consequence the sub-reflector 21 does not, to a substantial extent, obstruct energy flowing between the concave reflector 22 and the beam waveguide.
Abstract
In microwave communication systems it is common practice to use a beam waveguide to transmit energy between a waveguide (2) connected to transmitting and receiving equipment located at ground level and a main antenna reflector (not shown in Figure 3) mounted above ground level. Hitherto the waveguide (2) has terminated in a very large, accurately machined, horn which is necessary to produce a beam having a small angle of divergence suitable for entry into the beam waveguide (6).
The present invention proposes that this large (and very expensive) horn be replaced by a relatively small horn (18) which produces a beam having a relatively wide angle of divergence. By using a concave reflector (22) and a sub-reflector (21) in Cassegrain configuration this widely diverging beam is converted into a more nearly parallel (or a totally parallel) beam which enters the beam waveguide (6) as illustrated.
Description
- This invention relates to apparatus for feeding electromagnetic signals, particularly in the microwave and radio frequency areas of the spectrum between, on the one hand a reflector belonging to an antenna and, on the other hand, transmitting and/or receiving equipment for delivering signals to or receiving them from the antenna.
- Particularly when large reflectors are required, such as is normal for satellite communication systems, it is necessary for practical reasons that the transmitting and/or receiving equipment be at ground level whilst the reflector be raised above ground level. An ordinary waveguide provided with rotating joints can be used for feeding energy between the equipment on the ground and the reflector but such waveguides are inefficient in that much of the energy is lost during transmission along them. It is therefore generally preferred to use what is known as a "beam waveguide" which is defined for the purpose of this Specification as an arrangement of reflectors designed to direct radiation along a desired path.
- A typical known apparatus of the type described above is shown very schematically in Figure 1 of the accompanying drawings. Referring to Figure 1 there is shown a building 1 which houses microwave signal detecting and generating equipment lA. Microwave energy passes from lA along a
short waveguide 2 which terminates in a large corrugated radiating horn 3. This emits a beam 4 of radiation which diverges frompoint 5 inside the mouth of the horn with an angle of divergance (a). - The diverging beam 4 enters a
beam waveguide 6 mounted on a support structure 7 which has wheels 8 riding on a circular track 9. The support structure 7 and thebeam waveguide 6 can thus be rotated about a.vertical axis X-X. The means for effecting such rotation is not illustrated in the drawing. - The
beam waveguide 6 has a lower tubular portion containing aflat reflector 10 from which the diverging beam 4 is reflected to aparabolic reflector 11. The latter has its focus at ornear point 5 and therefore produces an essentially parallel beam which is directed to anotherparabolic reflector 12. Thereflector 12 brings the beam to a focus atpoint 13 after reflection from aflat reflector 14. The beam, now diverging again, is scattered from a sub-reflector 15 to amain reflector 16 from where the signals are transmitted into the atmosphere or into space if the apparatus is located in an extra terrestrial position. - The
main reflector 16 has supportarms 17 pivotted about a horizontal axis Y-Y to the support structure 7. Thebeam waveguide 6 is divided as indicated at 6A into upper and lower parts so as to enable the upper part to rotate with thereflector 16 about the axis Y-Y. The means for rotating thereflector 16 about the horizontal axis Y-Y is not shown in the drawing. By selecting the appropriate positions of rotation about the axes X-X and Y-Y thereflector 16 can be made to point in any desired direction. - In arrangements such as shown in Figure 1 the horn 3 needs to radiate most of the energy within a narrow angle (a), so that an acceptable proportion of the energy is incident upon
reflectors - This invention provides apparatus for transmitting or receiving electromagnetic signals comprising a path for the signals extending: from a signal generator or detector to a member located in front of a concave reflector; from the said member to the concave reflector; from the concave reflector, past opposite sides of the said member to a beam waveguide; and from the beam waveguide to a main reflector.
- The concave reflector provided by this invention enables a widely diverging beam, from for example a small horn, to be converted into a beam having a smaller angle of divergance, such as would be obtained from a large horn. The cost of the conventional large horn is thus substantially eliminated at the expense of a relatively inexpensive concave reflector. The concave reflector can be designed to give a beam having as small an angle of divergance as may be required or even a parallel beam or a converging beam. The invention therefore makes it possible in cases to eliminate the need for concave reflectors in the beam waveguide thus further reducing the cost of the system.
- The aforementioned comments with regard to the angle of divergance of the beam refer to the system when operating as a transmitter. Similar comments of course apply to the apparatus when operating as a receiver in which case the aforementioned angle of divergance will be the angle of convergance.
- The said "member" can be a relatively small horn positioned in front of the concave reflector and directed towards the latter. However, such a horn requires a waveguide feed which, because of its necessary cross- sectional area, obstructs to a significant.extent the path between the concave reflector and the beam waveguide. It is therefore preferred that the said "member" be a sub-reflector positioned axially in front of the concave reflector and arranged so that the said path passes through an aperture in the centre of the concave reflector between the sub-reflector and a horn or equivalent member located behind the concave reflector.
- A sub-reflector as described above can be supported on relatively slender supports which do not present any significant obstacle to the passage of radiation along the aforementioned path.
- An example of how the invention may be performed will now be described with reference to Figures 2,3 and 4 of the accompanying drawings in which:-
- Figure 2 is a schematic vertical cross-section through apparatus constructed in accordance with the invention;
- Figure 3 is similar to Figure 2 but shows a modification; and
- Figure 4 is a more detailed view of part of the apparatus shown in Figure 3.
- Referring firstly to Figure 2, this apparatus has
components only components component 6 are shown in Figure 2. The large horn 3 of Figure 1 is replaced, in Figure 2, by asmall horn 18 which emits, or receives, abeam 19 whose angle of divergance, or convergance, is denoted by the letter (b). This angle (b) is much greater than the corresponding angle (a) of Figure 1 because of the smaller horn size. Thebeam 19 passes through a central aperture in aconcave reflector 20 behind which thehorn 18 is situated. The,beam is then reflected from asub-reflector 21 onto the front of theconcave reflector 20. - The
concave reflector 20 is elliptical in section having one focus at thepoint 5, which is the same as thepoint 5 shown in Figure l; and its other focus at apoint 5A. - The convex reflector 2l is hyperbolic in section, having one focus at 5A and its other focus at 5B inside the mouth of the
horn 18. Accordingly, the beam eflected from thereflector 20 is brought to a focus atpoint 5. The angle of convergance and divergance atpoint 5 is chosen to be equal to the angle (a) of Figure 1 so that after passingpoint 5 the beam behaves exactly as described with reference to Figure 1. The apparatus depicted in Figure 2 can thus be used as a direct replacement for the large horn 3 of Figure 1 without the need arising for any other modifications to the equipment. - Figure 3 shows an apparatus similar to that of Figure 2 but modified by the replacement of the
elliptical reflector 20 by aparabolic reflector 22 having its focus at thepoint 5A. This produces a parallel beam which is directed into thebeam waveguide 6. Since the beam is parallel there is no need for curved reflectors in the beam waveguide. Thus thereflectors - In order to avoid any reduction in efficiency of the system by obstruction of the beam by the
sub-reflector 21, the latter is preferably shaped so that it directs no radiation, or a relatively low intensity of radiation to the central portion of thereflector 22. This is illustrated in Figure 4 where regions of the beam having maximum intensity values are shown by the shaded areas. From Figure 4 it is apparent that thesub-reflector 21 is effective to shape the beam 4 into an annular configuration which is incident on thepart 23 of thereflector 22 but not to a substantial extent on the central part of this reflector. As a consequence thesub-reflector 21 does not, to a substantial extent, obstruct energy flowing between theconcave reflector 22 and the beam waveguide.
Claims (4)
1. Apparatus for transmitting or receiving electromagnetic signals comprising a path for the signals extending: from a signal generator or detector to a member located in front of a concave reflector; from the said member to the concave reflector and past opposite sides of the said member to a beam waveguide; and from the beam waveguide to a main reflector.
2. Apparatus according to claim 1 in which the said member is a sub-reflector and in which that part of the path which extends from the transmitter or receiver to the sub-reflector passes through an aperture in the concave reflector to a sub-reflector and thence to the said concave reflector.
3. Apparatus according to claim 2 in which the said part of the path includes a horn located behind the concave reflector and pointing through the aperture towards the sub-reflector.
4. Apparatus according to claim 2 or 3 in which the sub-reflector is shaped so that the said path extends past opposite sides of the sub-reflector but is not to a substantial extent intercepted thereby.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8022088A GB2079538A (en) | 1980-07-04 | 1980-07-04 | Beam waveguide feed for antenna |
GB8022088 | 1980-07-04 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0043689A2 true EP0043689A2 (en) | 1982-01-13 |
EP0043689A3 EP0043689A3 (en) | 1982-01-20 |
Family
ID=10514563
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP81302955A Withdrawn EP0043689A3 (en) | 1980-07-04 | 1981-06-29 | Beam waveguide feed for antenna |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0043689A3 (en) |
JP (1) | JPS5748805A (en) |
GB (1) | GB2079538A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1071109C (en) * | 1995-05-19 | 2001-09-19 | 花王株式会社 | Hair care product |
US6890894B2 (en) | 2000-02-22 | 2005-05-10 | The Procter & Gamble Company | Fatty acids, soaps surfactant systems, and consumer products based thereon |
US6916777B2 (en) | 1997-10-23 | 2005-07-12 | The Procter & Gamble Company | Fatty acids, soaps, surfactant systems, and consumer products based thereon |
WO2009064608A1 (en) | 2007-11-16 | 2009-05-22 | Raytheon Company | Systems and methods for waveguides |
CN102324596A (en) * | 2011-06-09 | 2012-01-18 | 中国工程物理研究院电子工程研究所 | TE01 mode Bend structure of millimeter wave boardband plane mirror type |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7352150B2 (en) * | 2019-08-27 | 2023-09-28 | 三菱電機株式会社 | Beam reflection mechanism, reflector drive mechanism and reflector antenna device |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1245072A (en) * | 1958-11-21 | 1960-11-04 | Improvements in the transmission of electromagnetic wave beams | |
US3521288A (en) * | 1968-07-10 | 1970-07-21 | Us Air Force | Antenna array employing beam waveguide feed |
JPS5261458A (en) * | 1975-11-17 | 1977-05-20 | Mitsubishi Electric Corp | Beam power supply antenna system |
-
1980
- 1980-07-04 GB GB8022088A patent/GB2079538A/en not_active Withdrawn
-
1981
- 1981-06-29 EP EP81302955A patent/EP0043689A3/en not_active Withdrawn
- 1981-07-03 JP JP10434381A patent/JPS5748805A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1245072A (en) * | 1958-11-21 | 1960-11-04 | Improvements in the transmission of electromagnetic wave beams | |
US3521288A (en) * | 1968-07-10 | 1970-07-21 | Us Air Force | Antenna array employing beam waveguide feed |
JPS5261458A (en) * | 1975-11-17 | 1977-05-20 | Mitsubishi Electric Corp | Beam power supply antenna system |
Non-Patent Citations (4)
Title |
---|
IEEE International Antennas and Propagation Symposium, Dec. 1969, Austin, Mac Graw-Hill, New York, (US) Y TAKEICHI et al.: "The Dual-Reflector Launcher for the Beam Waveguide", pages 70-77 * |
IEEE International Antennas and Propagation Symposium, Sept. 1970, Columbus, Mac Graw-Hill, New York, (US) T. KITSUREGAWA et al.: "The Four Reflector Launcher for the Beam Waveguide", pages 94-99 * |
L'ONDE ELECTRIQUE, Vol. 51, Nr. 6, June 1971, Masson Paris, (FR) S. DRABOWITCH et al.: "Conception Radioelectrique d'une Antenne Experimentale de Telecommunication Spatiale dans la Gamme 10-35 GHz", pages 502-508 * |
PATENT ABSTRACTS OF JAPAN, Vol. 1, No. 127, page 5601E77, & JP-A-52 061 458 (20-05-1977) * |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1071109C (en) * | 1995-05-19 | 2001-09-19 | 花王株式会社 | Hair care product |
US6916777B2 (en) | 1997-10-23 | 2005-07-12 | The Procter & Gamble Company | Fatty acids, soaps, surfactant systems, and consumer products based thereon |
US6949502B2 (en) | 1997-10-23 | 2005-09-27 | The Procter & Gamble Company | Fatty acids, soaps, surfactant systems, and consumer products based thereon |
US6890894B2 (en) | 2000-02-22 | 2005-05-10 | The Procter & Gamble Company | Fatty acids, soaps surfactant systems, and consumer products based thereon |
US6992057B2 (en) * | 2000-02-22 | 2006-01-31 | The Procter & Gamble Company | Fatty acids, soaps, surfactant systems, and consumer products based thereon |
WO2009064608A1 (en) | 2007-11-16 | 2009-05-22 | Raytheon Company | Systems and methods for waveguides |
EP2215522A1 (en) * | 2007-11-16 | 2010-08-11 | Raytheon Company | Systems and methods for waveguides |
EP2215522A4 (en) * | 2007-11-16 | 2015-02-25 | Raytheon Co | Systems and methods for waveguides |
CN102324596A (en) * | 2011-06-09 | 2012-01-18 | 中国工程物理研究院电子工程研究所 | TE01 mode Bend structure of millimeter wave boardband plane mirror type |
CN102324596B (en) * | 2011-06-09 | 2013-10-09 | 中国工程物理研究院电子工程研究所 | TE01 mode Bend structure of millimeter wave boardband plane mirror type |
Also Published As
Publication number | Publication date |
---|---|
JPS5748805A (en) | 1982-03-20 |
EP0043689A3 (en) | 1982-01-20 |
GB2079538A (en) | 1982-01-20 |
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Inventor name: BRAIN, JOHN RICHARD |