US3438040A - Horn antenna having plural convergent waveguide paths - Google Patents

Horn antenna having plural convergent waveguide paths Download PDF

Info

Publication number
US3438040A
US3438040A US581954A US3438040DA US3438040A US 3438040 A US3438040 A US 3438040A US 581954 A US581954 A US 581954A US 3438040D A US3438040D A US 3438040DA US 3438040 A US3438040 A US 3438040A
Authority
US
United States
Prior art keywords
paths
aperture
aerial
plates
wave guide
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 - Lifetime
Application number
US581954A
Other languages
English (en)
Inventor
Mathew Frederick Radford
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
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
Application filed by Marconi Co Ltd filed Critical Marconi Co Ltd
Application granted granted Critical
Publication of US3438040A publication Critical patent/US3438040A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H01Q21/08—Arrays of individually energised antenna units similarly polarised and spaced apart the units being spaced along or adjacent to a rectilinear path
    • 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

Definitions

  • This invention relates to directional aerials and has for its object to provide improved directional aerials which are suitable for use in radar systems and shall have a direction of maximum directivity which is substantially independent of frequency over its useful range and which shall also have wide band characteristics.
  • a directional aerial comprises means providing a plurality of pairs of convergent wave guide paths opening into a common aerial aperture surface, the ends of said paths remote from said surface opening into a further wave guide path having a central feed, the paths of each said convergent pair being at opposite acute angles to said further path and the overall path lengths from said central feed to the ends of said convergent paths in said aperture surface being substantially the same throughout.
  • the common aerial aperture may be a planar rectangular aperture but preferably it is composed of two planar rectangular portions which meet at a common shorter side and at obtuse angle at the middle of the aperture so that said aperture is swept back from its centre to its ends.
  • the convergent wave guide paths are provided by means of inclined plates extending from the aperture surface to the further wave guide path and which are substantially parallel at least over a portion of their lengths starting from the further wave guide.
  • These plates may be parallel over their whole lengths but, preferably, their ends near the aperture are curved to provide curved matching sections.
  • a preferred construction is of very approximately segmental shape defined by two side plates, and an angled back plate having a straight, in-line, central portion which is symmetrical about the central feed and continues into two similar straight outer portions extending to the aerial aperture and at opposite obtuse angles with said central portion, there being provided between said side plates, a central structure which at least approximates in shape to that of an isosceles triangle and has its base spaced from parallel to and substantially co-extensive with the in-line central portion of said back plate, there being also provided between said side plates a plurality of spaced plates having at least a portion of their lengths parallel to one side of said triangular structure and extending from the aperture to an imaginary surface spaced from one of said outer portions of the back plate and a symmetrically arranged like plurality of spaced plates having at least a portion of their lengths parallel to the other side of said structure and similarly extending from the aperture to an imaginary surface similarly spaced from the other of said outer portions of the back plate, the lengths of the acute angled paths
  • the ends of the plates near the aperture are curved so as to provide curved matching sections;
  • the side plates are so shaped that the aperture surface is composed of two rectangular surface portions which meet at a common shorter side at an obtuse angle so that said aperture is swept back from the centre to its ends by amount of between a quarter of a wave length and one wavelength; and the sides of the approximately triangular structure are curved near the apex so as to meet at a very acute angle at the centre of the aperture.
  • the side plates may be parallel to one another or they may be divergent in the direction of the aerial aperture so that the approximately segmental aerial is flared.
  • the feed may be a simple central feed provided by a wave guide opening into the middle of the length of the further wave guide path, i.e. in the preferred cheese-like embodiments, opening into the middle of the length of the space between the in-line central portion of the back plate and the base of the at least approximately triangular structure.
  • a wave guide opening into the middle of the length of the further wave guide path i.e. in the preferred cheese-like embodiments, opening into the middle of the length of the space between the in-line central portion of the back plate and the base of the at least approximately triangular structure.
  • there may be a separate feed to each half of the aerial the middle of the length of the further wave guide path being interrupted and the two inner ends of the two paths produced by said interruption connected to two feeders fed through a 3 db coupler.
  • the best arrangement is that in which the spacing, measured in the aerial aperture surface, between the ends of adjacent paths terminating in that surface is half a wave length and the spacing between the other ends of said paths terminating in the aforesaid further wave guide path is a quarter of a wave length.
  • the former spacing is increased to approximately two-thirds of a wave length and the latter spacing to one half of this.
  • the worst arrangement, from the point of view of impedance matching, is that in which the former spacing is increased to one wave length and the latter to half this and such dimensioning should be avoided in carrying out the invention.
  • FIGURES 1 and 2 are mutually perpendicular views of one embodiment
  • FIGURE 3 is a part view of the same nature as FIG- URE 2, illustrating a modification
  • FIGURE 4 is a View showing a preferred embodiment
  • FIGURE 5 is a diagram showing two of the paths through the aerial of FIGURE 4.
  • the aerial therein shown is of very approximately segmental form.
  • the sides are defined by two side plates 1 and 2 which, in the example illustrated, are parallel to one another though they could be divergent in the direction of the aerial aperture if a flared construction is required.
  • the back of the aerial is defined by an angled back plate consisting of a straight, in-line central portion 3 which continues into two similar straight outer portions 4 and 5 extending to the aperture of the aerial which is planar and rectangular.
  • each plate 7 or 8 extends from the aerial aperture to one or other of two imaginary surfaces, one spaced from and slightly inclined with respect to the outer portion 4 of the back plate and the other spaced from and slightly inclined with respect to the outer portion 5 thereof.
  • a single feeder 11 opens into the space between the central portion 3 of the base plate and the base 6 of triangular structure.
  • the aerial aperture is rectangular and planar and a plurality of paths exist between the feeder 11 and the said aperture.
  • these paths have a common portion between the portion 3 of the back plate and the base 6 of the triangular structure and then turn through acute angles near the outer portion 4 to go through the spaces at either side of each of the plates 7.
  • the paths have a common portion between the portion 3 and the base 6 and then turn through acute angles near the outer portion 5 to go through the spaces on either side of each of the plates 8. All these paths are made of the same length. Accordingly the direction of maximum directivity, which will be quite sharp, is at right angles to the plane of the aerial aperture, the direction of the maximum lobe being perpendicular to said aperture at the middle of its length.
  • FIGURE 1 there is a simple central feed. It is obviously possible, however, to use a double feed, i.e. an input arrangement for so-called static split.
  • FIGURE 3 illustrates this.
  • the middle of the common portion of the paths to the aerial aperture is interrupted so as to form two paths, one directed to the left and the other to the right, with their adjacent ends close together. These paths are fed by two waveguides, one of which is referenced 11' and the other 11".
  • These waveguides are fed via a 3 db coupler 12, the right hand input being applied via the wave guide 13 and the left hand input being applied via the wave guide 14.
  • Aerials in accordance with this invention may be constructed to operate at any of a wide range of frequencies and are particularly suitable for use at frequencies in the range of 1,000 mc./s. to 10,000 mc./s. They are remarkably free from frequency-dependent directivity. Moreover, as compared with the commonly employed linear arrays of the slotted wave guide type, they are wide band. Experiment indicates that a bandwidth ratio of 3:2 is readily obtainable. This compares very favourably with the bandwidth ratio of about 11:10 which is approximately all that is generally obtained with linear arrays of the slotted wave guide type. Also it will be noted that the structure is simple and strong mechanically.
  • aerials in accordance with the invention may be used conjointly, e.g. end to end with their apertures in a common plane, in order to obtain high powers.
  • FIGURES 1 to 3 may with advantage be modified in such manner that the paths (of equal length) through the aerial are continued by extending the plates 7 and 8 into extensions each approximately of a wavelength long, lying in planes at right angles to the plane of the aperture and positioned between the side plates 1 and 2. In this construction, therefore, each of the equal length paths is bent through an angle near the aerial aperture.
  • An additional extension plate parallel to the other extensions extends from the apex of the triangular structure.
  • matching means are preferably provided at or near the angles in the separate paths.
  • the change in direction between the plates 7 and 8 and the extension plates may be made gradually e.g. by curving the plates where the angular change occurs or altering the plate directions in that position in a series of small steps.
  • the plates 7 and 8 are curved at their aperture ends to form curved matching sections and the aerial aperture is swept back by an amount indicated by the dimension S.
  • a small change (compared to FIG- URES 1 and 2) is made in the geometry of the platesthere being a small departure from the isosceles triangle shape of FIGURES l and 2to correct for defocussing error introduced by the sweep back.
  • the apex end of the sides 9, 10 of the triangular structure are curved to come together at a very acute angle.
  • the reflections from the aperture ends of the paths are staggered without appreciably interfering with the frequency independence.
  • FIGURE 4 the right hand half of which is drawn with the side plate (the top one in FIGURE 4) removed to show the plates 8, the parts below the top plate being shown in broken lines in the left hand half of the figure. Also in FIGURE 4, is indicated a flare FL formed by extending the top and bottom side plates (corresponding to the plates 1 and 2 of FIGURE 1) beyond the ends of the plates 7 and 8 and diverging them.
  • FIGURE 4 is a diagram showing two of the paths (the extreme left and right hand paths through the right hand half of the aerial of FIGURE 4) through the aerial of FIGURE 4.
  • the parts of the paths are represented as though they were all straight. Different points on these paths are indicated by reference letters which are also shown in FIGURE 4. It may be shown that, for perfect compensation Where kg. is the guided wave length and A the wavelength in free space. Theoretically this question can be satisfied only at one frequency (the mid-band frequency) since A is not proportional to Ag. However the error is negligible over a practically adequate wide band, since the amount of sweepback, EF, is relatively small.
  • FIGURE 4 there is shown a simple central feed as in FIGURE 2. Obviously a double feed, as in FIGURE 3, providing static split, could be used.
  • a directional aerial comprising means providing a plurality of pairs of convergent wave guide paths opening into a common aerial aperture surface, the ends of said paths remote from said surface opening into a further wave guide path having a central feed, the paths of each said convergent pair being at opposite acute angles to said further path and the overall path lengths from said central feed to the ends of said convergent paths in said aperture surface being substantially the same throughout.
  • an aerial as claimed in claim 6 wherein the ends of the plates near the aperture are curved so as to provide curved matching sections; the side plates are so shaped that the aperture surface is composed of two rectangular surface portions which meet at a common shorter side at an obtuse angle so that said aperture is swept back from the centre to its ends by an amount of between a quarter of a wave length and one wave length; and the sides of the approximately triangular structure are curved near the apex so as to meet at a very acute angle at the centre of the aperture.
  • An aerial as claimed in claim 1 wherein the feed is a simple central feed provided by a Wave guide opening into the middle of the length of the further wave guide path.
  • An aerial as claimed in claim 1 wherein there is a separate feed to each half of the aerial, the middle of the length of the further wave guide path being interrupted and the two inner ends of the two paths produced by said interruption connected to two feeders fed through a 3 db coupler.

Landscapes

  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Aerials With Secondary Devices (AREA)
US581954A 1965-10-15 1966-09-26 Horn antenna having plural convergent waveguide paths Expired - Lifetime US3438040A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB43919/65A GB1148888A (en) 1965-10-15 1965-10-15 Improvements in or relating to directional aerials

Publications (1)

Publication Number Publication Date
US3438040A true US3438040A (en) 1969-04-08

Family

ID=10430921

Family Applications (1)

Application Number Title Priority Date Filing Date
US581954A Expired - Lifetime US3438040A (en) 1965-10-15 1966-09-26 Horn antenna having plural convergent waveguide paths

Country Status (4)

Country Link
US (1) US3438040A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1148888A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL6614534A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
SE (1) SE345346B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0524622A1 (fr) * 1991-07-26 1993-01-27 Alcatel Espace Antenne-réseau pour ondes hyperfréquences
EP0677889A1 (en) * 1994-04-15 1995-10-18 Telefonaktiebolaget Lm Ericsson Distribution network
WO2017175782A1 (en) * 2016-04-05 2017-10-12 Nidec Elesys Corporation Waveguide device and antenna array

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2628311A (en) * 1948-11-04 1953-02-10 Rca Corp Multiple slot antenna
GB894342A (en) * 1959-08-25 1962-04-18 Decca Record Co Ltd Improvements in or relating to directional aerial systems

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2628311A (en) * 1948-11-04 1953-02-10 Rca Corp Multiple slot antenna
GB894342A (en) * 1959-08-25 1962-04-18 Decca Record Co Ltd Improvements in or relating to directional aerial systems

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0524622A1 (fr) * 1991-07-26 1993-01-27 Alcatel Espace Antenne-réseau pour ondes hyperfréquences
FR2679704A1 (fr) * 1991-07-26 1993-01-29 Alcatel Espace Antenne-reseau pour ondes hyperfrequences.
US5327147A (en) * 1991-07-26 1994-07-05 Alcatel Espace Microwave array antenna having sources of different widths
EP0677889A1 (en) * 1994-04-15 1995-10-18 Telefonaktiebolaget Lm Ericsson Distribution network
US5565878A (en) * 1994-04-15 1996-10-15 Telefonaktiebolaget Lm Ericsson Distribution network
WO2017175782A1 (en) * 2016-04-05 2017-10-12 Nidec Elesys Corporation Waveguide device and antenna array
JP2019514281A (ja) * 2016-04-05 2019-05-30 日本電産株式会社 導波路装置およびアンテナアレイ
US10594045B2 (en) 2016-04-05 2020-03-17 Nidec Corporation Waveguide device and antenna array

Also Published As

Publication number Publication date
NL6614534A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1967-04-17
GB1148888A (en) 1969-04-16
SE345346B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1972-05-23

Similar Documents

Publication Publication Date Title
US2764757A (en) Metallic lens antennas
US3568204A (en) Multimode antenna feed system having a plurality of tracking elements mounted symmetrically about the inner walls and at the aperture end of a scalar horn
US4843403A (en) Broadband notch antenna
US4218686A (en) Yagi-type antennas and method
US3110030A (en) Cone mounted logarithmic dipole array antenna
US2650985A (en) Radio horn
CN111201672A (zh) 使端射天线和低频天线并置的系统、设备和方法
US3290688A (en) Backward angle travelling wave wire mesh antenna array
Mailloux An overlapped subarray for limited scan application
US3099836A (en) V-strip antenna with artificial dielectric lens
US2718592A (en) Antenna
US3050730A (en) Broadband plate antenna
US3193831A (en) Logarithmic periodic antenna
US2290800A (en) Antenna
US3509572A (en) Waveguide fed frequency independent antenna
US3355740A (en) Log-periodic zig zag antenna
US4005433A (en) Small wavelength high efficiency antenna
US3438040A (en) Horn antenna having plural convergent waveguide paths
USRE25740E (en) Log periodic backward wave antenna array
US2895134A (en) Directional antenna systems
US2714659A (en) Broad band unidirectional antenna
US5142290A (en) Wideband shaped beam antenna
US3273159A (en) Log periodic antenna comprised of parallel fed quad elements
US2785397A (en) Annular lens antenna
US2807800A (en) High frequency directional aerials