US3553702A - Waveguide radiator with perpendicular scattering posts at aperture - Google Patents

Waveguide radiator with perpendicular scattering posts at aperture Download PDF

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Publication number
US3553702A
US3553702A US750784A US3553702DA US3553702A US 3553702 A US3553702 A US 3553702A US 750784 A US750784 A US 750784A US 3553702D A US3553702D A US 3553702DA US 3553702 A US3553702 A US 3553702A
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waveguide
posts
aperture
scattering
radiator
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US750784A
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William M Spanos
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TDK Micronas GmbH
ITT Inc
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Deutsche ITT Industries GmbH
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/02—Arrangements for de-icing; Arrangements for drying-out ; Arrangements for cooling; Arrangements for preventing corrosion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/02—Waveguide horns
    • H01Q13/0241—Waveguide horns radiating a circularly polarised wave
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/06—Waveguide mouths
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/24—Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction

Definitions

  • a waveguide radiator is provided having perpendicular scattering posts placed within "a shaped aperture end of the waveguide to produce a circularly polarized microwave radiator as a result of spherically scattering of th waves by the posts.
  • this invention relates to waveguide radiators and more particularly to microwave high power, hemispherical coverage, circularly polarized radiators.
  • the basic problem in designing a'hernispherical cover,- age waveguide radiator is that of obtaining a sufiiciently broad E-plane and H-plane pattern.
  • broad H-plane coverage has been obtained by removing the side walls of the guide and inserting a scattering post in the mouth of the aperture.
  • a broader E-plane pattern can be obtained by closing up the aperture the E-plane.
  • An object of this invention is to providc a microwave, high power, hemispherical coverage, circularly polarized waveguide radiator.
  • Another object of this invention is to provide a circular polarization over a broad beamwidth.
  • Still another object of this invention is to provide cooling means for use during high power operation of the radiator.
  • a waveguide having shaped aperture in which is mounted perpendicular scatteringposts which cooperate with said shaped aperture to produce a space radiation pattern having a broad E-plane and H-plane.
  • a feature of this invention is that the scattering pins are designed to permit a coolant to flow therethrough for cooling the structure during high power applications.
  • FIG. 2 illustrates the waveguide radiator according to the invention.
  • FIG. 1 shows a metallic scattering post 1 1; Patent 0 inside ,theaperturefi, at its center.
  • the waveguide corners 4 have been removed by a symmetrical cut so as to pro- ;duce the broadened-pattern."
  • the beam broadening occurs in the H-plane so that a broad beam linearly polarized wave guide radiator results.
  • a broader E-plane pattern can be obtained by closing up the aperture in the E-plane.
  • FIG. 2 shows how the circularly ,polarized. hemispherical coverage antenna is structured.
  • Asquare waveguide 5 is shown for purposes of illustratio'n into -which is coupled acircularly polarized input 6.
  • Symmetrical scattering posts 8 having a diameter d and a'length L are mounted within the shaped aperture end 7 of the waveguide to provide a symmetrical radiator.
  • the symmetrically shaped aperture 7 has an effective diameter D and a length l which has been removed from all four corner sections of the waveguide 5. In the case of the circular waveguide, the removed portions would be 90 apart and at the effective diameter D.
  • the scattering posts 8 are hollow and connected to coolant line inputs 9 and cooling line odtputs 10.
  • Control of the radiation pattern in the H-plane is accomplished by selection ofthe diameter of d and the length l of the waveguide wall which is removed.
  • Control of the radiation pattern in the E-plane is accomplished by control of the effective diameter D of the waveguide and the length L of the scattering post 8 which is also the separation of the parallel walls.
  • Dielectric loading is used in the aperture region 7 so that the initial diameter of the aperture is as small as possible and the pattern of the square waveguide is as broad as possible without the additional pattern broadening means. Teflon can be used for the dielectric loading because its loss is low and it can withstand the resultant temperature rises which occur.
  • a quartz" dielectric matching section can be inserted within the dielectrically loaded waveguide.
  • Cooling must be provided for the aperture region of the radiator.
  • the dielectric, and copper losses will be greatest in the mouth ofjthe aperture because of the fringing fields which occur and because of the manner by which the radiation is being forced.
  • the scattering posts are driven strongly in order to produce a radiation back toward the input throat of the waveguide. This will cause considerable heat to be generated in the posts which must be removed to prevent an unreasonable temperature rise.
  • the means for preventing the temperature rise is to provide cooling by forcing liquid coolant through the interior of the posts.
  • the liquid can be removed through the coolant output lines so as to provide continual circulation through the posts.
  • the coolant lines 9, 10 are made of copper and run along the metallic forces of the transition and the waveguide to conduct heat away from the aperture region.
  • a waveguide radiator having an aperture produced by cutting away the corners of the waveguide and placing within the mouth of said aperture scattering posts to provide a circularly polarized high powered microwave antenna which results from spherically scattering the input wave by the symmetrical scattering posts.
  • the scattering posts are designed hollow so that a coolant may flow therethrough for cooling the structure during high powered power applications.
  • a hemispherical coverage waveguide radiator comprising:
  • perpendicular scattering posts mounted within a shaped aperture of said waveguide which cooperates with said posts to determine the space radiation pattern
  • a radiator according to claim 2 wherein:
  • said H-plane radiation pattern is controlled by the diameter (d) of the scattering posts and the length (l) of the waveguide wall which has been removed;
  • said E-plane radiation pattern is controlled by the diameter (D) at the mouth of said aperture and the length (L) of the scattering posts.
  • a hemispherical coverage waveguide radiator for radiating a circularly polarized microwave comprising:
  • a square Waveguide having its corner portions removed; perpendicular scattering posts symmetrically mounted in the aperture mouth of said waveguide, the combined configuration determining the space radiation pattern; and t i a circularly polarized input wave coupled to said waveguide, whereby, a broad E-plane and H-plane pattern is produced by the spherical scattering of said input wave by said posts.
  • said H-plane' radiation pattern is controlled by the diameter (d) of the scattering posts and the length (l) of the waveguide corners which has been removed from the walls;
  • said E-plane radiation pattern is controlled by the diameter (D) at the mouth of said aperture and the length (L) of the scattering posts between the walls 8.

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Abstract

A WAVEGUIDE RADIATOR IS PROVIDED HAVING PERPENDICULAR SCATTERING POSTS PLACED WITHIN A SHAPED APERTURE END OF THE WAVEGUIDE TO PRODUCE A CIRCULARLY POLARIZED MICROWAVE RADIATOR AS A RESULT OF SPHERICALLY SCATTERING OF THE WAVES BY THE POSTS.

Description

Jan. 5, 1971 w. M. SPANOS WAVEGUIDE RADIATOR WITH PERPENDICULAR SCATTERING POSTS AT APERTURE Filed Aug. '7, 1968 (PR/0R ART) INVENTOR v WILL/AM M. SPA/V05 MJM ATTORNEY U.S. Cl. 343-756 .8 Claims ABSTRACT OF THE DISCLOSURE A waveguide radiator is provided having perpendicular scattering posts placed within "a shaped aperture end of the waveguide to produce a circularly polarized microwave radiator as a result of spherically scattering of th waves by the posts.
' BACKGROUND OF THE INVENTION In general this invention relates to waveguide radiators and more particularly to microwave high power, hemispherical coverage, circularly polarized radiators.
At low frequencies, where coaxial cables are used to transmit high power, hemispherical coverage, circularly polarized antennas have been designed using crossed dipoles in front of a conical reflector. At microwave frequencies, waveguide radiators must be used to handle high average powers which can range from two to 50 kilowatts. The design described here. consists of a waveguide radiator which has the capability of handling these high powers.
The basic problem in designing a'hernispherical cover,- age waveguide radiator is that of obtaining a sufiiciently broad E-plane and H-plane pattern. With rectangular guide radiating a single polarization; broad H-plane coverage has been obtained by removing the side walls of the guide and inserting a scattering post in the mouth of the aperture. A broader E-plane pattern can be obtained by closing up the aperture the E-plane.
SUMMARY OF THE INVENTION An object of this invention is to providc a microwave, high power, hemispherical coverage, circularly polarized waveguide radiator.
Another object of this invention is to provide a circular polarization over a broad beamwidth.
Still another object of this invention is to provide cooling means for use during high power operation of the radiator.
According to the broader aspects of this invention, I have provided a waveguide having shaped aperture in which is mounted perpendicular scatteringposts which cooperate with said shaped aperture to produce a space radiation pattern having a broad E-plane and H-plane.
A feature of this invention is that the scattering pins are designed to permit a coolant to flow therethrough for cooling the structure during high power applications.
to the prior art; and
FIG. 2 illustrates the waveguide radiator according to the invention.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT To obtain a broader pattern than from an ordinary waveguide, FIG. 1 shows a metallic scattering post 1 1; Patent 0 inside ,theaperturefi, at its center. The waveguide corners 4 have been removed by a symmetrical cut so as to pro- ;duce the broadened-pattern." In the arrangement, according to the prior art, the beam broadening occurs in the H-plane so that a broad beam linearly polarized wave guide radiator results. A broader E-plane pattern can be obtained by closing up the aperture in the E-plane.
Therefore, to obtain a broad pattern for two simulta- .neous orthogonal polarizations which are required for circular polarization, a square or circular waveguide must be used with symmetrically shaped side walls and symmetrical scattering posts, FIG. 2 shows how the circularly ,polarized. hemispherical coverage antenna is structured.
Asquare waveguide 5 is shown for purposes of illustratio'n into -which is coupled acircularly polarized input 6. Symmetrical scattering posts 8 having a diameter d and a'length L are mounted within the shaped aperture end 7 of the waveguide to provide a symmetrical radiator. The symmetrically shaped aperture 7 has an effective diameter D and a length l which has been removed from all four corner sections of the waveguide 5. In the case of the circular waveguide, the removed portions would be 90 apart and at the effective diameter D. The scattering posts 8 are hollow and connected to coolant line inputs 9 and cooling line odtputs 10.
Control of the radiation pattern in the H-plane is accomplished by selection ofthe diameter of d and the length l of the waveguide wall which is removed. Control of the radiation pattern in the E-plane is accomplished by control of the effective diameter D of the waveguide and the length L of the scattering post 8 which is also the separation of the parallel walls.
Dielectric loading is used in the aperture region 7 so that the initial diameter of the aperture is as small as possible and the pattern of the square waveguide is as broad as possible without the additional pattern broadening means. Teflon can be used for the dielectric loading because its loss is low and it can withstand the resultant temperature rises which occur. For broadband impedance matching a quartz" dielectric matching section can be inserted within the dielectrically loaded waveguide.
Cooling must be provided for the aperture region of the radiator. The dielectric, and copper losses will be greatest in the mouth ofjthe aperture because of the fringing fields which occur and because of the manner by which the radiation is being forced. In addition, the scattering posts are driven strongly in order to produce a radiation back toward the input throat of the waveguide. This will cause considerable heat to be generated in the posts which must be removed to prevent an unreasonable temperature rise.
The means for preventing the temperature rise is to provide cooling by forcing liquid coolant through the interior of the posts. The liquid can be removed through the coolant output lines so as to provide continual circulation through the posts. The coolant lines 9, 10 are made of copper and run along the metallic forces of the transition and the waveguide to conduct heat away from the aperture region.
Tests results indicate that the following characteristics are typical of a radiator according to the design described herein:
Frequency: 4400-5000 mc.
SWR: Less than 1.25
Power: 10-20 kw. average Polarization: Circular Pattern Coverage: i degrees from the axis of radia- .tor (200 degree spherical sector omnidirectional around axis).
According to illustrated embodiment I have shown and described a waveguide radiator having an aperture produced by cutting away the corners of the waveguide and placing within the mouth of said aperture scattering posts to provide a circularly polarized high powered microwave antenna which results from spherically scattering the input wave by the symmetrical scattering posts. Also, the scattering posts are designed hollow so that a coolant may flow therethrough for cooling the structure during high powered power applications.
While I have described above the principles of my invention according to specific apparatus, this description is to be considered only by way of example and not as a limitation to the scope of my invention as set forth in the objects and features thereof and in the accompanying claims. I i.
I claim:
1. A hemispherical coverage waveguide radiator comprising:
a symmetrical waveguide;
perpendicular scattering posts mounted within a shaped aperture of said waveguide which cooperates with said posts to determine the space radiation pattern; and
a circularly polarized input wave coupled to said waveguide, whereby, a broad E-plane and H-plane pattern is radiated due to the spherical scattering of said input wave by said posts.
2 A radiator according to claim 1 wherein said perpendicular scattering posts are symmetrical shaped and mounted to symmetrical portions of said shaped aperture.
3. A radiator according to claim 2 wherein:
said H-plane radiation pattern is controlled by the diameter (d) of the scattering posts and the length (l) of the waveguide wall which has been removed; and
said E-plane radiation pattern is controlled by the diameter (D) at the mouth of said aperture and the length (L) of the scattering posts. v
4. A radiator according to claim 3 wherein said posts are hollow and. have a coolant flowing therethrough for cooling the structure during high power applications.
5. A hemispherical coverage waveguide radiator for radiating a circularly polarized microwave comprising:
a square Waveguide having its corner portions removed; perpendicular scattering posts symmetrically mounted in the aperture mouth of said waveguide, the combined configuration determining the space radiation pattern; and t i a circularly polarized input wave coupled to said waveguide, whereby, a broad E-plane and H-plane pattern is produced by the spherical scattering of said input wave by said posts.
6. A radiator according to claim 5 wherein said perpendicular scattering posts are symmetrical shaped and mounted to the remaining symmetrical portions of the side walls of said waveguide.
7. A radiator according to claim 6 wherein:
said H-plane' radiation pattern is controlled by the diameter (d) of the scattering posts and the length (l) of the waveguide corners which has been removed from the walls; and
said E-plane radiation pattern is controlled by the diameter (D) at the mouth of said aperture and the length (L) of the scattering posts between the walls 8. A radiator according to claim 7 wherein said posts are hollow and have a forced liquid coolant flowing through the interior of the posts during high power applications.
References Cited UNITED STATES PATENTS 2,756,419 7/1956 Foley et al. 343-772 3,382,501 5/1968 Fee 343-772 3,445,852 5/ 1969 Karlson 343-772 FOREIGN PATENTS v 787,756 12/1957 Great Britain 343786 ELI LIEBERMAN, Primary Examiner US. Cl. X.R. 343--786
US750784A 1968-08-07 1968-08-07 Waveguide radiator with perpendicular scattering posts at aperture Expired - Lifetime US3553702A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4119951A (en) * 1977-02-16 1978-10-10 Gilles Garon Microwave intrusion sensing units and antenna therefor
EP0017530A1 (en) * 1979-03-28 1980-10-15 Thomson-Csf Radiating source constituted by a dipole excited by a waveguide, and its use in an electronic scanning antenna
GB2396485A (en) * 2002-12-23 2004-06-23 Toshiba Res Europ Ltd Antenna array with scattering structure
US7924564B1 (en) 2009-10-30 2011-04-12 Raytheon Company Integrated antenna structure with an embedded cooling channel

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4119951A (en) * 1977-02-16 1978-10-10 Gilles Garon Microwave intrusion sensing units and antenna therefor
EP0017530A1 (en) * 1979-03-28 1980-10-15 Thomson-Csf Radiating source constituted by a dipole excited by a waveguide, and its use in an electronic scanning antenna
FR2452804A1 (en) * 1979-03-28 1980-10-24 Thomson Csf RADIANT SOURCE CONSTITUTED BY A DIPOLE EXCITED BY A WAVEGUIDE, AND ELECTRONIC SCANNING ANTENNA COMPRISING SUCH SOURCES
GB2396485A (en) * 2002-12-23 2004-06-23 Toshiba Res Europ Ltd Antenna array with scattering structure
GB2396485B (en) * 2002-12-23 2005-03-16 Toshiba Res Europ Ltd Method and apparatus for increasing the number of strong eigenmodes multiple-input multiple-output (MIMO) radio channel
EP1434306B1 (en) * 2002-12-23 2017-10-04 Kabushiki Kaisha Toshiba Method and apparatus for increasing the number of strong eigenmodes in a mutliple-input multiple output (MIMO) radio channel
US7924564B1 (en) 2009-10-30 2011-04-12 Raytheon Company Integrated antenna structure with an embedded cooling channel
EP2317601A1 (en) * 2009-10-30 2011-05-04 Raytheon Company An integrated antenna structure with an imbedded cooling channel
US20110103018A1 (en) * 2009-10-30 2011-05-05 Raytheon Company Integrated antenna structure with an embedded cooling channel

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