EP0527569A1 - Mikrowellenantenne - Google Patents

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Publication number
EP0527569A1
EP0527569A1 EP92306789A EP92306789A EP0527569A1 EP 0527569 A1 EP0527569 A1 EP 0527569A1 EP 92306789 A EP92306789 A EP 92306789A EP 92306789 A EP92306789 A EP 92306789A EP 0527569 A1 EP0527569 A1 EP 0527569A1
Authority
EP
European Patent Office
Prior art keywords
horn
mouth
ridges
antenna according
ridge
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Withdrawn
Application number
EP92306789A
Other languages
English (en)
French (fr)
Inventor
Hari Lajpat Jairam
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.)
BAE Systems Electronics Ltd
Original Assignee
GEC Marconi Ltd
Marconi Co Ltd
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
Priority claimed from GB919116330A external-priority patent/GB9116330D0/en
Application filed by GEC Marconi Ltd, Marconi Co Ltd filed Critical GEC Marconi Ltd
Publication of EP0527569A1 publication Critical patent/EP0527569A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • H01Q13/0275—Ridged horns
    • 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
    • H01Q19/06—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 refracting or diffracting devices, e.g. lens
    • H01Q19/08—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 refracting or diffracting devices, e.g. lens for modifying the radiation pattern of a radiating horn in which it is located

Definitions

  • This invention relates to microwave antennas.
  • the invention relates to microwave antennas having a wide beamwidth in both azimuth and elevation and being operable over a wide frequency band for orthogonally polarized signal components.
  • Such antennas find application, for example, in airborne ground surveillance radar systems where the antenna is mounted on the nose of the aircraft and directed ahead of the aircraft.
  • One such antenna is described in our co-pending patent application No.9104319.
  • One object of the present invention is to provide a novel form of microwave antenna which, while maintaining the large bandwidth and return loss performance of the antenna referred to above has improved power handling and/or weight characteristics.
  • a microwave horn antenna for use with signals having orthogonal polarization plane components, comprises a circular horn adapted to interface with a square polarizer having axial metallic ridges providing differential polarization-plane phase-shifting, the horn comprising corresponding metallic ridges adapted to abut the polarizer ridges, the internal face of each horn ridge being continuous with the internal face of the corresponding polarizer ridge, the horn ridges extending to the mouth of the horn and being tapered down to substantially zero radial dimension at the mouth, and dielectric means disposed at the mouth providing beam shaping and matching.
  • the dielectric means preferably comprises a lens mounted on the mouth of the horn and tapered dielectric matching means disposed within the horn mouth.
  • the lens preferably comprises a cylindrical annulus surrounding the horn mouth and extending forward of it.
  • the lens may comprise a cylindrical block having an axial cylindrical hole in one end face to accommodate the horn mouth and a smaller diameter axial cylindrical hole in the opposite face, the two holes being separated by a wall of dielectric material.
  • the matching means preferably comprises tapered ridge portions, each extending from the axis of the horn to the tapered face of a respective horn ridge throughout the axial length of the horn ridge, each ridge portion being aligned with a respective horn ridge.
  • the ridge portions may be integrated in a conical member of cruciform cross-section, the base of the conical member abutting the wall of said lens.
  • Figure 1 shows the combined polarizer and antenna horn making up the antenna unit.
  • the polarizer 1 is shown to the left of an interface plane 3 and the circular horn 5 to the right of this interface.
  • the polarizer 1 is a standard waveguide component of square section and the horn 5 is circular,or rather, cylindrical, having an internal diameter slightly greater than the internal side dimension of the square polarizer 1. Both components are provided with flanges (4,6) by means of which they are screwed together.
  • the antenna transmits (and in some applications may receive) signals having electric field components in both horizontal and vertical planes.
  • Circularly polarized signals in space are derived from (or are converted to) plane polarized signals in the transmitter/receiver associated with the antenna. This requires a 90° differential phase shift between the horizontal and vertical signal components and it is the function of the polarizer 1 to provide this shift.
  • the polarizer consists of a square metallic waveguide 7 having longitudinal metal ridges 9 fixed centrally along each internal face. One pair of opposing ridges 9 are plain while the other pair, ie in the orthogonal plane containing the waveguide axis, are corrugated.
  • Components in the 'corrugated ridge plane' are delayed relative to those in the orthogonal plane and the length of the polarizer is chosen to produce a relative delay of 90°.
  • the left hand end of the polarizer 1 (not shown) is coupled to the transmitter/receiver in known manner.
  • the present invention is concerned with the design of the antenna horn when the horn is required to couple to a standard polarizer of the above kind and is also required to be circular to obtain, as far as possible, rotational symmetry of the radiation characteristic, ie the same radiation pattern in all axial planes.
  • An object of the presently described antenna design is that the bandwidth and return loss performance should be comparable with that of the antenna referred to above, but that the power handling capacity and weight factor should be significantly improved.
  • a major problem in the design of the present antenna is the limitation imposed by the need to interface with the existing polarizer, of fixed dimensions, which has to be employed.
  • the square polarizer being considered has an internal side dimension of 19.4 millimetres which cannot be increased.
  • the ridges 9 have a radial depth of 5 millimetres.
  • the internal diameter of the cylindrical metallic horn is set at 22 millimetres.
  • Metallic ridges 13 are provided in the circular horn 5 to correspond with and abut those (9) in the polarizer.
  • the ridges 13 have inner faces and lateral faces continuous with the corresponding faces of the polarizer ridges 9.
  • the horn ridges thus have a radial dimension of 6.38 millimetres.
  • the ridges 13 may be formed integrally with the cylindrical horn 5, eg by extrusion and machining, fixed on to it by brazing, or more simply by screws passing through the wall 15 of the circular guide, into tapped holes in the ridges.
  • the ridges 13 extend from the interface 3 to the plane 17 of the mouth of the horn. They have a length, which is not critical, of 40 millimetres. However, it is kept to a minimum consistent with maintaining the performance, in the interests of weight reduction, At the mouth end they taper down to zero radial dimension over an axial extent of 15 millimetres, giving a taper angle of about 23°.
  • a 'conical' member 19 of dielectric material eg PTFE.
  • This member 19 comprises essentially four tapered ridge portions 20 as illustrated in Figure 5, whose taper faces complement the taper faces of the horn ridges 13, as shown in Figure 1.
  • the power handling capacity of the antenna is to some extent limited by the mass of dielectric material used for matching and beam-forming purposes, It has been found that the mass can be reduced in certain ways without detracting significantly from the matching capabilities.
  • an axial hole 22 is provided in the cone member 19, this hole 22 being open ended.
  • a further mass reduction is provided by relieving the base of the cone member to provide a cylindrical recess 24 having an axis aligned with that of the cone.
  • the hole 19 breaks out into this recess 24.
  • the diameter of the hole 22 is 5 millimetres, ie about one-quarter wavelength at an opening frequency of about 15 GHz, ie towards the upper end of the operating band.
  • the diameter of the cylindrical recess 24 is 12 millimetres, about three-quarters of a wavelength at 18 GHz, while its depth is 4 millimetres. The dimensions may be varied about these values and the latter depth value may vary between the hole 22 diameter and a value one-quarter down from this.
  • the cruciform nature of the conical member 19 may also be seen in Figure 4, the cone ridges 20 being in alignment with and partly obscured by the horn ridges 13.
  • This lens produces a widening of the beam (ie the radiation characteristic) to give a beam angle of about 90° at the 3dB points.
  • the lens is 40 millimetres outside diameter, 16 millimetres inside diameter (ie the front bore 23), 20 millimetres axial length and has an internal shoulder in which the horn cylinder 5 fits snugly to a depth of 10 millimetres.
  • a feature of the present design is that the forward bore 23 of the lens 27 does not extend right through the lens. There is a remaiming wall 29, of thickness 2 millimetres which assists considerably in achieving a good match between the horn and free space.
  • the basic dielectric lens 27 inherently reacts differently to horizontally and vertically polarized signal components.
  • the beam pattern is widened for vertically polarized components (ie components transverse to this azimuth beam plane) as compared with its response to horizontally polarized components, because of the inherent nature of the characteristics of the circular horn.
  • a simple dielectric lens would thus produce a departure from the desired rotational symmetry for both polarization components since, in the azimuth plane the vertical component is transverse to the plane so that the 'vertical polarization' beam is widened, whereas, in the elevation plane the horizontal component is transverse to the plane so that the 'horizontal polarization' beam is widened.
  • the lens 27 requires matching to free space to improve the return loss characteristic, ie to level out and reduce the peaks In the characteristic.
  • the wall 29 of the lens 27 produces a good free space match but the solution adopted in Application No.9104319 may be incorporated additionally to provide further improvement.
  • This solution comprises grooving the radiating surface of the lens with, either, concentric equi-spaced grooves (or a single groove), or with radial grooves, or a combination of the two. Slots generally do of course tend to reduce beamwidth.
  • radial slots tend to reduce the beamwidth for polarization transverse to the scanning plane, eg for vertical polarization in the azimuth plane, to a much greater extent than they affect the beamwidth for polarization aligned with the scanning plane.
  • radial slots improve the matching considerably, and particularly above 12 GHz, for polarization transverse to the scanning plane (eg for vertical polarization in the azimuth plane).
  • the arrangement which could be adopted in the present embodiment to take best advantage of these various effects is a combination of eight radial slots spaced at 45°, and one concentric slot. These slots would have a width of 2 millimetres and a depth of 5 millimetres.

Landscapes

  • Waveguide Aerials (AREA)
  • Aerials With Secondary Devices (AREA)
EP92306789A 1991-07-29 1992-07-24 Mikrowellenantenne Withdrawn EP0527569A1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9116330 1991-07-29
GB919116330A GB9116330D0 (en) 1991-07-29 1991-07-29 Microwave antenna
GB9200042 1992-01-03
GB9200042A GB2258345B (en) 1991-07-29 1992-01-03 Microwave antenna

Publications (1)

Publication Number Publication Date
EP0527569A1 true EP0527569A1 (de) 1993-02-17

Family

ID=26299305

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92306789A Withdrawn EP0527569A1 (de) 1991-07-29 1992-07-24 Mikrowellenantenne

Country Status (1)

Country Link
EP (1) EP0527569A1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995001661A1 (en) * 1993-06-29 1995-01-12 Antenna Down Link, Inc. Multiple-frequency microwave feed assembly
GB2284908A (en) * 1993-12-17 1995-06-21 Ford Motor Co Fuel injection pulse width compensation
WO1999063624A1 (en) * 1998-06-02 1999-12-09 Cambridge Industries Limited Antenna feed and a reflector antenna system and a low noise (lnb) receiver, both with such an antenna feed
WO2002087018A1 (de) * 2001-04-21 2002-10-31 Woetzel Frank E Anordnung zur erregung einer zentralfokussierten reflektorantenne
DE102008015409A1 (de) * 2008-03-20 2009-09-24 KROHNE Meßtechnik GmbH & Co. KG Dielektrische Hornantenne
CN108565555A (zh) * 2018-06-21 2018-09-21 河南师范大学 高增益h面喇叭天线

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE556362A (de) * 1955-09-16
US3205500A (en) * 1961-02-24 1965-09-07 North American Aviation Inc Circularly polarizing horn antenna having dielectric insert which provides reduced axial ratio over broad band
US3758882A (en) * 1970-11-11 1973-09-11 Licentia Gmbh Polarization converter for microwaves
EP0131328A1 (de) * 1983-07-01 1985-01-16 Rtc-Compelec Sende-Empfangseinrichtung für ein Radar zur Anwesenheitswahrnehmung und Verfahren zur Herstellung
WO1987006066A1 (en) * 1986-03-25 1987-10-08 The Marconi Company Limited Wideband horn antenna
WO1988002933A1 (en) * 1986-10-20 1988-04-21 Hughes Aircraft Company Orthogonal mode electromagnetic wave launcher

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE556362A (de) * 1955-09-16
US3205500A (en) * 1961-02-24 1965-09-07 North American Aviation Inc Circularly polarizing horn antenna having dielectric insert which provides reduced axial ratio over broad band
US3758882A (en) * 1970-11-11 1973-09-11 Licentia Gmbh Polarization converter for microwaves
EP0131328A1 (de) * 1983-07-01 1985-01-16 Rtc-Compelec Sende-Empfangseinrichtung für ein Radar zur Anwesenheitswahrnehmung und Verfahren zur Herstellung
WO1987006066A1 (en) * 1986-03-25 1987-10-08 The Marconi Company Limited Wideband horn antenna
WO1988002933A1 (en) * 1986-10-20 1988-04-21 Hughes Aircraft Company Orthogonal mode electromagnetic wave launcher

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995001661A1 (en) * 1993-06-29 1995-01-12 Antenna Down Link, Inc. Multiple-frequency microwave feed assembly
GB2284908A (en) * 1993-12-17 1995-06-21 Ford Motor Co Fuel injection pulse width compensation
GB2284908B (en) * 1993-12-17 1998-07-15 Ford Motor Co Fuel injector pulse width compensation
WO1999063624A1 (en) * 1998-06-02 1999-12-09 Cambridge Industries Limited Antenna feed and a reflector antenna system and a low noise (lnb) receiver, both with such an antenna feed
US6831612B2 (en) 1998-06-02 2004-12-14 Channel Master Limited Antenna feed and a reflector antenna system and a low noise block (LNB) receiver, both with such an antenna feed
WO2002087018A1 (de) * 2001-04-21 2002-10-31 Woetzel Frank E Anordnung zur erregung einer zentralfokussierten reflektorantenne
US6876335B2 (en) 2001-04-21 2005-04-05 Frank E. Woetzel Arrangement for feeding a centrally focused reflector antenna
CN100376059C (zh) * 2001-04-21 2008-03-19 弗郎克·E·沃兹尔 中央聚焦式反射器天线的激励装置
HRP20030859B1 (en) * 2001-04-21 2008-04-30 Frank Device for exciting a centrally focused reflector antenna
DE102008015409A1 (de) * 2008-03-20 2009-09-24 KROHNE Meßtechnik GmbH & Co. KG Dielektrische Hornantenne
DE102008015409B4 (de) * 2008-03-20 2015-07-30 KROHNE Meßtechnik GmbH & Co. KG Dielektrische Hornantenne
CN108565555A (zh) * 2018-06-21 2018-09-21 河南师范大学 高增益h面喇叭天线

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