US3453632A - Single aperture multiple beam antennas - Google Patents

Single aperture multiple beam antennas Download PDF

Info

Publication number
US3453632A
US3453632A US585228A US3453632DA US3453632A US 3453632 A US3453632 A US 3453632A US 585228 A US585228 A US 585228A US 3453632D A US3453632D A US 3453632DA US 3453632 A US3453632 A US 3453632A
Authority
US
United States
Prior art keywords
channels
leaky
channel
antenna
walls
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
US585228A
Inventor
Jay Howard Harris
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.)
US Air Force
Original Assignee
US Air Force
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 US Air Force filed Critical US Air Force
Application granted granted Critical
Publication of US3453632A publication Critical patent/US3453632A/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
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • 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
    • H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/22—Longitudinal slot in boundary wall of waveguide or transmission line
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements

Definitions

  • This invention relates generally to multiple channel antennas and, more particularly, to multiple channel antennas which are capable of radiating a plurality of beams of microwave energy from a single aperture. Additionally, the beams from the antenna may be at widely different frequencies wherein the beams are arbitrarily oriented in space.
  • multiple beam antennas require extensive structures which, for aircraft purposes, increases the weight.
  • a plurality of apertures which are not capable of flush mounting to an aircraft or space vehicle cause added expense and structural modification to allow for this installation.
  • Another object of this invention is to provide a multiple channel antenna having beams at widely different frequencies which are arbitrarily oriented in space.
  • Still another object of this invention involves the production of multiple channel antennas which do not employ lenses or reflectors or directional couplers to produce multiple beams. Further, when a single frequency is used, the antenna is still capable of providing multiple beams.
  • a further object of this invention involves a multiple channel antenna of multiple frequencies which does not employ either optical or multiple mode wave guide techniques or spatial orientation in the aperture plane.
  • a still further object of this invention involves the production of multiple channel antennas which are economical to fabricate of conventional, currently available materials that lend themselves to mass production manufacturing techniques.
  • FIGURE 1 is a schematic representation of a multiple channel antenna capable of radiating two or more narrow, identical polarized beams of a microwave energy from a single aperture;
  • FIGURE 2 is a representation of the leaky wire grid wall details of the embodiments of FIGURE 1;
  • FIGURE 3 is a representation of a multiple frequency, multiple channel antenna utilizing leaky wire grid walls.
  • the antenna techniques of this invention provide for leaky wave propagation in each channel with a phase velocity that is determined by the width of the channel and the properties of the walls.
  • the wave loses power at a regular rate, radiation into space to form beams plus a coupling into leaky waves of other channels is eifected.
  • the ratio of power radiated into space to that coupled into the other channels is high, a multiple beam antenna with port isolation is obtained.
  • the waves are stated to be of the leaky type because some portion of the instant energy is transmitted through the wall at each reflection.
  • leaky waves are essentially radial wave guide modes and when leaky wire grids and free space layers are alternated, the volume bounded by the leaky grids may be employed as propagation channels to produce a multiple beam antenna that radiates from a single aperture.
  • the antenna may be thought of as being the equivalent to having one antenna in front of another.
  • the obtaining of leaky waves require a layer of permeability less than that of free space, which in these embodiments is provided by walls comprised of regular arrays of wires.
  • FIGURE 1 there is shown a multiple channel antenna having upper and lower opposed, generally parallel, rectangular, metallic, conducting planes 10 and 12 which are interconnected by means of a metallic, conducting, rear side wall 14 extending along opposed edges of the planes 10 and 12.
  • Leaky wire grid walls 16 define separate propagation channels, the wall details of which are illustrated most clearly in FIGURE 2.
  • Each leaky wire grid wall 16 is comprised of at least two parallel layers or rows of wires 18 which make electrical contact with both of the metallic, conducting planes 10 and 12.
  • a plurality of rows of wires are utilized in order to provide thickness to the walls 16, since, when the walls of the channel are thick, well defined leaky waves may be propagated; however, the attenuation rate of the waves must also be considered into the selection of the wall thickness. If the thickness is too great, the rate of power loss may be insuflicient for practical applications. It has been experimentally verified that a spacing of .25 inch to .3 inch between the rows of wires 18 produced the required waves. The spacing between adjacent wires in a row is determined by the frequency of the energy in the channels.
  • a planar array is formed from stacked linear arrays and multiple beams are produced in the plane that is parallel to the linear arrays.
  • Microwave energy is introduced into one or more of the channels which form linear arrays in the region between the leaky wire grid walls 16 of FIGURE 1 in order to have energy propagate as a TE leaky wave mode with the propagation constant controlled by the width of the channel and the properties of the walls 16.
  • Power is radiated by the leaky wave mode and forms a beam in space from each channel which is directly related to the propagation constant of the leaky wave mode.
  • the critical angle of a leaky wire grid wall 16 is selected so that it lies between the beam pointing angle of the channel below the wall and the beam pointing angle of the channel above the wall.
  • the width of each channel is selected such that succeeding channels which are closer to the aperture on the side opposite the rear side wall 14 generate beams which are closer to end-fire.
  • An antenna, as described relative to FIGURE 1, with only two channels could be employed as a Doppler velocity sensor radar antenna since four beams with the same polarization may be generated and the velocity information may be obtained by measurement of the frequency shift of each beam.
  • the antenna of FIGURE 3 is capable of radiating a plurality of beams at widely different frequencies with arbitrary orientations in space.
  • This antenna is comprised of metallic, conducting planes 10' and 12' with a metallic, conducting, rear side wall 14 connected as described rela- 3 tive to FIGURE 1.
  • leaky wire grid walls 16 are also provided; however, metallic conducting walls 20 are added parallel to the metallic, conducting, planes and 12' thus defining a series of K,, band channels 22 with a pair of X-band channels 24 adjacent thereto.
  • an S-band channel 26 is provided. Each channel in this embodiment would be fed its energy from appropriately tapered wave guides.
  • beams may be produced at more than one frequency with each beam generated by the same wave guide mode. All of this is done with a single aperture opposite the rear side wall 14 wherein the sensitivity of the antenna to fabrication errors is small.
  • the propagation channels of this embodiment are bounded above and below the conducting planes and on the sides by the leaky wire grid walls except for the rear side wall.
  • a TE leaky wave mode at appropriate frequency is launched in each channel by an appropriate, tapered wave guide (not shown).
  • the height of each channel is selected for design convenience while the width is dictated by the propagation constant to yield the beam in a desired direction.
  • the walls 16 are designed to appear effectively impermeable to frequencies propagating to the left While they are semi permeable to the channel to the left and invisible to frequencies propagated in channels further to the left. This design is obtained if the equivalent frequency of a wall is taken equal to the frequency of the channel to the left of the wall; therefore, closer spacings of the wires 18' forming the leaky wire grid walls 16 are used for the higher frequencies.
  • the channels may be formed by inserting polyfoam spacers between the leaky grid walls 16, which may be constructed of narrow strips of very thin, etched circuit boards.
  • the wires may be etched on one side of the strip and a conducting material on the edges of the strip would insure electrical contact between the wires 18' and the conducting planes 10, 12 or 10', 12.
  • a single wall is formed by more than one row of wires, thus at least a pair of the strips would be utilized for each wall.
  • conventional microwave energy absorbent material may be provided at the end of the channels remote from the feed in order to avoid the unwanted radiation of energy therefrom.
  • Means for radiating a plurality of polarized beams of microwave energy from a single aperture comprising:
  • each forming a linear array said channels being formed by a pair of opposed, generally parallel, metallic, conducting planes,
  • leaky wire grid walls in electrical contact with and extending between said opposed conducting planes and parallel to said rear side wall.
  • leaky wire grid walls are formed of at least two parallel rows of wires which make contact with said opposed conducting walls.
  • Means as defined in claim 4 including additional metallic, conducting planes between and parallel with said pair of opposed, generally parallel, metallic, conducting planes, said additional metallic, conducting planes being in contact with said rear side wall.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Waveguide Aerials (AREA)

Description

J. H. HARRIS July 1, 1969 SINGLE APERTURE MULTIPLE BEAM ANTENNAS Filed Oct. 6, 1966 United States Patent 3 453 632 SINGLE APERTURE MULTIPLE BEAM ANTENNAS Jay Howard Harris, Bellevue, Wash., assignor to the United States of America as represented by the Secretary of the Air Force Filed Oct. 6, 1966, Ser. No. 585,228 Int. Cl. H01q 13/02 US. Cl. 343-772 6 Claims This invention relates generally to multiple channel antennas and, more particularly, to multiple channel antennas which are capable of radiating a plurality of beams of microwave energy from a single aperture. Additionally, the beams from the antenna may be at widely different frequencies wherein the beams are arbitrarily oriented in space.
Generally, multiple beam antennas require extensive structures which, for aircraft purposes, increases the weight. In addition, a plurality of apertures which are not capable of flush mounting to an aircraft or space vehicle cause added expense and structural modification to allow for this installation.
Accordingly, it is a primary object of this invention to provide multiple channel antennas capable of radiating two or more beams of microwave energy from a single aperture.
It is another object of this invention to provide multiple channel antennas for a plurality of beams which are identically polarized.
It is still another object of this invention to provide antennas having a plurality of channels which radiate from a single aperture.
It is a further object of this invention to provide multiple channel antennas wherein the beam for each channel originates from an independent feed.
It is a still further object of this invention to provide a multiple channel antenna capable of radiating a plurality of beams of more than one microwave frequency.
Another object of this invention is to provide a multiple channel antenna having beams at widely different frequencies which are arbitrarily oriented in space.
Still another object of this invention involves the production of multiple channel antennas which do not employ lenses or reflectors or directional couplers to produce multiple beams. Further, when a single frequency is used, the antenna is still capable of providing multiple beams.
A further object of this invention involves a multiple channel antenna of multiple frequencies which does not employ either optical or multiple mode wave guide techniques or spatial orientation in the aperture plane.
A still further object of this invention involves the production of multiple channel antennas which are economical to fabricate of conventional, currently available materials that lend themselves to mass production manufacturing techniques.
These and other advantages, features and objects of the invention will become more apparent from the following description taken in connection with the illustrative, embodiments in the accompanying drawings, wherein:
FIGURE 1 is a schematic representation of a multiple channel antenna capable of radiating two or more narrow, identical polarized beams of a microwave energy from a single aperture;
FIGURE 2 is a representation of the leaky wire grid wall details of the embodiments of FIGURE 1; and
FIGURE 3 is a representation of a multiple frequency, multiple channel antenna utilizing leaky wire grid walls.
The antenna techniques of this invention provide for leaky wave propagation in each channel with a phase velocity that is determined by the width of the channel and the properties of the walls. When the wave loses power at a regular rate, radiation into space to form beams plus a coupling into leaky waves of other channels is eifected. When the ratio of power radiated into space to that coupled into the other channels is high, a multiple beam antenna with port isolation is obtained. The waves are stated to be of the leaky type because some portion of the instant energy is transmitted through the wall at each reflection.
It has been found that leaky waves are essentially radial wave guide modes and when leaky wire grids and free space layers are alternated, the volume bounded by the leaky grids may be employed as propagation channels to produce a multiple beam antenna that radiates from a single aperture. The antenna may be thought of as being the equivalent to having one antenna in front of another. The obtaining of leaky waves require a layer of permeability less than that of free space, which in these embodiments is provided by walls comprised of regular arrays of wires.
Referring to FIGURE 1 there is shown a multiple channel antenna having upper and lower opposed, generally parallel, rectangular, metallic, conducting planes 10 and 12 which are interconnected by means of a metallic, conducting, rear side wall 14 extending along opposed edges of the planes 10 and 12. Leaky wire grid walls 16 define separate propagation channels, the wall details of which are illustrated most clearly in FIGURE 2. Each leaky wire grid wall 16 is comprised of at least two parallel layers or rows of wires 18 which make electrical contact with both of the metallic, conducting planes 10 and 12.
A plurality of rows of wires are utilized in order to provide thickness to the walls 16, since, when the walls of the channel are thick, well defined leaky waves may be propagated; however, the attenuation rate of the waves must also be considered into the selection of the wall thickness. If the thickness is too great, the rate of power loss may be insuflicient for practical applications. It has been experimentally verified that a spacing of .25 inch to .3 inch between the rows of wires 18 produced the required waves. The spacing between adjacent wires in a row is determined by the frequency of the energy in the channels.
Thus, a planar array is formed from stacked linear arrays and multiple beams are produced in the plane that is parallel to the linear arrays. Microwave energy is introduced into one or more of the channels which form linear arrays in the region between the leaky wire grid walls 16 of FIGURE 1 in order to have energy propagate as a TE leaky wave mode with the propagation constant controlled by the width of the channel and the properties of the walls 16. Power is radiated by the leaky wave mode and forms a beam in space from each channel which is directly related to the propagation constant of the leaky wave mode. The critical angle of a leaky wire grid wall 16 is selected so that it lies between the beam pointing angle of the channel below the wall and the beam pointing angle of the channel above the wall. The width of each channel is selected such that succeeding channels which are closer to the aperture on the side opposite the rear side wall 14 generate beams which are closer to end-fire.
An antenna, as described relative to FIGURE 1, with only two channels could be employed as a Doppler velocity sensor radar antenna since four beams with the same polarization may be generated and the velocity information may be obtained by measurement of the frequency shift of each beam.
The antenna of FIGURE 3 is capable of radiating a plurality of beams at widely different frequencies with arbitrary orientations in space. This antenna is comprised of metallic, conducting planes 10' and 12' with a metallic, conducting, rear side wall 14 connected as described rela- 3 tive to FIGURE 1. In this embodiment, leaky wire grid walls 16 are also provided; however, metallic conducting walls 20 are added parallel to the metallic, conducting, planes and 12' thus defining a series of K,, band channels 22 with a pair of X-band channels 24 adjacent thereto. Finally, an S-band channel 26 is provided. Each channel in this embodiment would be fed its energy from appropriately tapered wave guides.
Thus, beams may be produced at more than one frequency with each beam generated by the same wave guide mode. All of this is done with a single aperture opposite the rear side wall 14 wherein the sensitivity of the antenna to fabrication errors is small. The propagation channels of this embodiment are bounded above and below the conducting planes and on the sides by the leaky wire grid walls except for the rear side wall. A TE leaky wave mode at appropriate frequency is launched in each channel by an appropriate, tapered wave guide (not shown). The height of each channel is selected for design convenience while the width is dictated by the propagation constant to yield the beam in a desired direction. The walls 16 are designed to appear effectively impermeable to frequencies propagating to the left While they are semi permeable to the channel to the left and invisible to frequencies propagated in channels further to the left. This design is obtained if the equivalent frequency of a wall is taken equal to the frequency of the channel to the left of the wall; therefore, closer spacings of the wires 18' forming the leaky wire grid walls 16 are used for the higher frequencies.
By having a frequency channel antenna of the type described relative to FIGURE 3, communication may be effected on one beam while ground mapping may be accommodated on another with the same aperture.
Although the invention has been described relative to particular embodiments, it should be understood that the invention is capable of a variety of alternative embodiments within the spirit and scope of the appended claims. For example, the channels may be formed by inserting polyfoam spacers between the leaky grid walls 16, which may be constructed of narrow strips of very thin, etched circuit boards. The wires may be etched on one side of the strip and a conducting material on the edges of the strip would insure electrical contact between the wires 18' and the conducting planes 10, 12 or 10', 12. A single wall is formed by more than one row of wires, thus at least a pair of the strips would be utilized for each wall. In addition, conventional microwave energy absorbent material may be provided at the end of the channels remote from the feed in order to avoid the unwanted radiation of energy therefrom.
I claim:
1. Means for radiating a plurality of polarized beams of microwave energy from a single aperture comprising:
a plurality of channels, each forming a linear array, said channels being formed by a pair of opposed, generally parallel, metallic, conducting planes,
a rear side wall extending along an edge of each of said opposed conducting planes, and
leaky wire grid walls in electrical contact with and extending between said opposed conducting planes and parallel to said rear side wall.
2. Means as defined in claim 1 wherein said leaky wire grid walls are formed of at least two parallel rows of wires which make contact with said opposed conducting walls.
3. Means as defined in claim 2 wherein the wires of said rows of wires forming said leaky wire grid walls are equally spaced.
4. Means as defined in claim 2 wherein said wires of said rows of Wires forming said leaky wire grid walls are equally spaced in each row but the wires in some of said walls do not have the same spacing as in others of said walls.
5. Means as defined in claim 4 wherein the aperture from which said antenna radiates is opposite said rear side and the channels are arranged such that the channels having higher frequencies and closer spacing of the wires in said wall are remote from said aperture.
6. Means as defined in claim 4 including additional metallic, conducting planes between and parallel with said pair of opposed, generally parallel, metallic, conducting planes, said additional metallic, conducting planes being in contact with said rear side wall.
References Cited UNITED STATES PATENTS 2,957,173 10/1960 Rotman 343772 3,015,100 12/1961 Rotman 343772 ELI LIEBERMAN, Primary Examiner.
U.S.Cl.X.R.

Claims (1)

1. MEANS FOR RADIATING A PLURALITY OF POLARIZED BEAMS OF MICROWAVE ENERGY FROM A SINGLE APERTURE COMPRISING: A PLURALITY OF CHANNELS, EACH FORMING A LINEAR ARRAY, SAID CHANNELS BEING FORMED BY A PAIR OF OPPOSED, GENERALLY PARALLEL, METALLIC, CONDUCTING PLANES, A REAR SIDE WALL EXTENDING ALONG AN EDGE OF EACH OF SAID OPPOSED CONDUCTING PLANES, AND LEAKY WIRE GRIDE WALLS IN ELECTRICAL CONTACT WITH AND EXTENDING BETWEEN SAID OPPOSED CONDUCTING PLANES AND PARALLEL TO SAID REAR WALL.
US585228A 1966-10-06 1966-10-06 Single aperture multiple beam antennas Expired - Lifetime US3453632A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US58522866A 1966-10-06 1966-10-06

Publications (1)

Publication Number Publication Date
US3453632A true US3453632A (en) 1969-07-01

Family

ID=24340563

Family Applications (1)

Application Number Title Priority Date Filing Date
US585228A Expired - Lifetime US3453632A (en) 1966-10-06 1966-10-06 Single aperture multiple beam antennas

Country Status (1)

Country Link
US (1) US3453632A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2507825A1 (en) * 1981-06-15 1982-12-17 Trt Telecom Radio Electr Thin structure HF directional aerial for guided missile - has two conducting plates separated by dielectric layer of width determined by dielectric constant and cone angle of radiation
FR2687849A1 (en) * 1981-12-31 1993-08-27 Thomson Csf Flared-guide antenna provided with coupling bars with self-inductive impedance
US6864851B2 (en) * 2002-09-26 2005-03-08 Raytheon Company Low profile wideband antenna array

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2957173A (en) * 1957-03-20 1960-10-18 Rotman Walter Variable conductance trough waveguide antennas
US3015100A (en) * 1957-03-20 1961-12-26 Rotman Walter Trough waveguide antennas

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2957173A (en) * 1957-03-20 1960-10-18 Rotman Walter Variable conductance trough waveguide antennas
US3015100A (en) * 1957-03-20 1961-12-26 Rotman Walter Trough waveguide antennas

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2507825A1 (en) * 1981-06-15 1982-12-17 Trt Telecom Radio Electr Thin structure HF directional aerial for guided missile - has two conducting plates separated by dielectric layer of width determined by dielectric constant and cone angle of radiation
FR2687849A1 (en) * 1981-12-31 1993-08-27 Thomson Csf Flared-guide antenna provided with coupling bars with self-inductive impedance
US6864851B2 (en) * 2002-09-26 2005-03-08 Raytheon Company Low profile wideband antenna array

Similar Documents

Publication Publication Date Title
US4447811A (en) Dielectric loaded horn antennas having improved radiation characteristics
US4755821A (en) Planar antenna with patch radiators
US6297774B1 (en) Low cost high performance portable phased array antenna system for satellite communication
US4716415A (en) Dual polarization flat plate antenna
US2756421A (en) Beacon antenna
US6429825B1 (en) Cavity slot antenna
US5103241A (en) High Q bandpass structure for the selective transmission and reflection of high frequency radio signals
US3868695A (en) Conformal array beam forming network
US3039097A (en) Frequency-sensitive rapid-scanning antenna
US5467100A (en) Slot-coupled fed dual circular polarization TEM mode slot array antenna
US3225351A (en) Vertically polarized microstrip antenna for glide path system
WO1999034477A1 (en) Low cost high performance portable phased array antenna system for satellite communication
US3990079A (en) Log-periodic longitudinal slot antenna array excited by a waveguide with a conductive ridge
US3721988A (en) Leaky wave guide planar array antenna
US3419870A (en) Dual-plane frequency-scanned antenna array
US4180818A (en) Doppler navigation microstrip slanted antenna
US3290688A (en) Backward angle travelling wave wire mesh antenna array
JP3464107B2 (en) Dielectric waveguide slot antenna
CN217788798U (en) MxN millimeter wave terahertz planar dipole end-fire array antenna
Lechtreck Effects of coupling accumulation in antenna arrays
US5559523A (en) Layered antenna
US4746923A (en) Gamma feed microstrip antenna
US2659005A (en) Microwave antenna
US3453632A (en) Single aperture multiple beam antennas
CN116014454B (en) Low sidelobe high XPD millimeter wave gap waveguide slot array antenna