US2459768A - Apparatus for the radiation or reception of electromagnetic waves - Google Patents

Apparatus for the radiation or reception of electromagnetic waves Download PDF

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Publication number
US2459768A
US2459768A US536324A US53632444A US2459768A US 2459768 A US2459768 A US 2459768A US 536324 A US536324 A US 536324A US 53632444 A US53632444 A US 53632444A US 2459768 A US2459768 A US 2459768A
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US
United States
Prior art keywords
plane
conductor
dimensions
radiation
elements
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Expired - Lifetime
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US536324A
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English (en)
Inventor
Cork Edward Cecil
Bowman-Manifold Michael
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EMI Ltd
Electrical and Musical Industries Ltd
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EMI Ltd
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Filing date
Publication date
Application filed by EMI Ltd filed Critical EMI Ltd
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Publication of US2459768A publication Critical patent/US2459768A/en
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    • 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

Definitions

  • This invention relates to apparatus for the radiation or reception of electromagnetic waves. It is sometimes a requirement to provide a radiating or receiving element of electromagnetic waves which possesses at least in one plane a directivity pattern like that of a dipole element but not at the same time possessing the marked frequency selectivity of such an element.
  • transmitting or receiving apparatus for the radiation or reception of electromagnetic waves or" a given wavelength
  • a radiating or receiving element in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, the ratio ofsaid dimensions being at least twelve to one with the smaller dimensions no larger than one-sixth of the wavelength of the transmitted or received I waves.
  • the apparatus operates to radiate or receive electromagnetic waves polarised so that the electric component of force lies in the direction of said small dimensions. Waves of the H10 mode are. then set up in the space enclosed by said tubular conductor.
  • the directivity pattern of the apparatus in a plane parallel with the electric component force is a single lobe substantially as is obtained with a dipole, but is more concentrated in a plane normal to the electric component of force depending upon the magnitude of the larger dimensions of cross-section of said tubular conductor.
  • these dimensions sufliciently large a very high degree of directivity may be obtained in the latter plane.
  • said dimensions are chosen to be substantially one-half wavelength at the operating frequency then the directivity in said latter plane is not appreciably different from the broad lobe of a dipole.
  • an aerial according to the invention pact character Radiating elements as just described are suitable when arranged in an array for providing-a directivity pattern in a given plane which is substantially uniform in all directions.
  • apparatus for the radiation of electromagnetic waves comprising a plurality of radiating elements each in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, said radiating elements being radially arranged so that said waves Will be radiated by said apparatus substantially uniformly inall directions in a plane.
  • Such apparatus may be arranged to radiate waves having the electric component of force lying parallel to said plane or, normal thereto. Since wave-guide radiators are highly unselective such apparatus is particularly suitable for radiating Waves of a wide range of frequencies as in television transmission. s
  • the directivity diof highly comagrams may be distorted or may tend to be un- V stable.
  • the directivity diagram beside the single forwardly-directed lobe other lobes which are directed backwardly. Such other lobes may be undesirable.
  • a wave-guide trans mitting or receiving aerial comprising a tubular conductonwherein in order to attenuate currents of a certain frequency at the rim of said con ductor a further conductor is provided electrical,-
  • Figures 2 and 3 illustrate forms consisting of four elements and suitable for giving a circular diagram such as is required in broadcasting.
  • the radiating or receiving element is indicated by the reference numeral l and consists essentially of a tubular conductor of rectangular cross-section free to radiate or receive electromagnetic waves at its open end II, but electrically short-circuited at its other end l2.
  • the element [0 has dimensions in cross-section with which in one direction are small compared with those in a direction perpendicular thereto.
  • the greater of the two dimensions of cross-section is shown vertically in Figure 1 and the ratio of the larger to the smaller dimension of said crosssection is twelve to one or greater.
  • the greater dimension is a half wavelength or more at the operating frequency, whilst the smaller dimension is shown horizontally and is not greater than one-sixth of a wavelength and is preferably of the order of an eighth of a wavelength or less.
  • Energy is fed to or removed from the element ID by means of the coaxial feeder line I 3 which enters at one of the larger sides of the element ID at the point l4, and the inner conductor I 5 is continued into the space within the element in, as shown at l6, so as to be capable of exciting waves of the H mode in the space.
  • the exposed continuation I6 is tuned to resonance at the operating frequency by means of a short length of coaxial line in a manner that will be explained more fully with reference to Figure 2.
  • the radiation resistance of the continuation l6 depends not only upon the dimensions of crosssection of the element 1 0, but also on the distance of the element 16 from the reflecting end surface at the closed end i2 of the element [0 and from the sides of lesser dimensions, proper matching of the feeder l3 to the element I0 may be achieved by suitable location of the point of entry of the feeder into the side of the element I I). Said point of entry may be located at a distance of approximately one-quarter of a guide wavelength from the reflecting end of the element ID to provide suitable matching of said feeder to said element.
  • the portion of the tubular conductor [0 lying in front of the feeder may be of any length or may be omitted.
  • the space within the element I 0 may be filled With a dielectric material such as the material known by the registered trade-mark Polythene.
  • the arrangement may thereby be rendered highly compact.
  • a further conductor is provided surrounding the conductor l0 and electrically connected thereto.
  • the effective length of said conductor II, he, its length from the open end of the conductor l0 towards its rear is a quarter of a wavelength at the operating frequency so asto present a high impedance to currents at the operating frequency.
  • the directional diagram of the aerial is a single lobe pointing in the direction of the open end II of the element [0.
  • the lobe In the plane of the electric vector, which is the plane of the lesser dimension of cross-section of the element 10 the lobe is broad and gradually reduces to a minimum in the direction of the closed end of the element.
  • the plane of the magnetic vector which is vertical with the particular disposition of the figure there is a much greater directivity which depends on the greater dimension of cross-section of the element ID.
  • the nature of this directivity is indicated by the following table in which values of the greater dimension are given in the left-hand column and in the right-hand column the corresponding values of gain as compared with a dipole:
  • FIG 2 there is shown a radially-disposed arrangement of elements 20 similar to the element l0 described with reference to Figure l and joined to form a cruciform structure.
  • the elements 20 have their greater dimension of cross-section lying in the plane of the cruciform. This dimension is of the order of the operating wavelength so as to give directive diagrams to the individual elements 20 that add up to provide a substantially uniform diagram in said plane.
  • the aerial is thus suitable for broadcast transmission with a vertical polarisation.
  • Rim currents at the open ends of the elements 20 may be attenuated by quarter wavelength conductors (not shown but similar to that indicated in Figure 1 by the reference numeral I 1).
  • Waves of H10 mode are excited in the elements 20 by means of an energising element 22 similar to that designated at I6 in Figure 1 and arranged normal to the plane of the cruciform at the centre thereof.
  • the element 22 is a continuation of the coaxial feeding line 2
  • a cruciform structure may be formed of four radially-arranged radiating elements 24 having their greater dimension of cross-section lying vertically instead of horizontally, as in Figure 2.
  • Each radiating element is provided with an energising element 25 and these elements consist of the bent end portions of a feeding structure comprising four radial arms connected to the inner conductor of the coaxial line 21.
  • the feeding structure is arranged to lie in the mid-plane of the cruciform.
  • the feeding structure is tuned to resonance at the operating frequency by the provision of the further portion of coaxial line 23 after the manner of the like arrangement of Figure 2.
  • quarter-Wave conductors I! may be provided at the open ends of the radiating elements (these not however being shown in the figure)
  • the radiating elements may be flared out towards their openings and they may also be fed by guide type feeders instead of coaxial lines as described.
  • Apparatus for the radiation of electromagnetic waves comprising a plurality of radiating elements each in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, said radiating elements being radially arranged so that said waves will be radiated by said apparatus substantially uniformly in all directions in a plane and each of said radiating elements being energized by an energizing element including a portion of the inner conductor of a coaxial line disposed substantially at the center of the radially-arranged radiating elements, the outer conductor of said coaxial line being connected to said tubular conductors.
  • Apparatus for the radiation of electromagnetic waves comprising a pluralit of radiating elements each in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, said radiating elements being radially arranged so that said waves will be radiated by said apparatus substantially uniformly in all directions in a plane, said elements being so arranged that said small dimensions lie normally to said plane of radiation, said radiating elements being energized by a single energizing element comprising an integral portion of the inner conductor of a coaxial line disposed substantially at the center of said radially-arranged radiating elements, the outer conductor of said coaxial line being connected to said tubular conductors.
  • Apparatus for the radiation of electromagnetic waves comprising a plurality of radiating elements each in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, said radiating elements being radially arranged so that said Waves will be radiated by said apparatus substantially uniformly in all directions in a plane, said elements being so arranged that said small dimensions lie in said plane of radiation, said radiating elements being energized respectively by energizing elements carried by radially disposed conductors emanating substantially from the center of the radially-arranged radiating elements.
  • Apparatus for the radiation of electromagnetic waves comprising a plurality of radiating elements each in the form of a tubular conductor having dimensions in a plane lying transversely of said conductor which in one direction are small compared with those in a direction perpendicular thereto, said radiating elements being radially arranged so that said waves Will be radiated by said apparatus substantially uniformly in all directions in a plane, said elements being so arranged apparatus substantially uniformly in all directions in a.
  • said elements being so arranged that said small dimensions lie in said plane of radiation, said radiating elements being energized repectively by energizing elements carried by radially disposed arms connected to the inner conductor of a coaxial line, the outer conductor of said coaxial line being connected to said tubular conductors.
  • MICHAEL BOWMAN -MANIFOLD MICHAEL BOWMAN -MANIFOLD.

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  • Aerials With Secondary Devices (AREA)
US536324A 1943-05-21 1944-05-19 Apparatus for the radiation or reception of electromagnetic waves Expired - Lifetime US2459768A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB249519X 1943-05-21

Publications (1)

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US2459768A true US2459768A (en) 1949-01-18

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US (1) US2459768A (US07223432-20070529-C00017.png)
BE (1) BE465944A (US07223432-20070529-C00017.png)
CH (1) CH249519A (US07223432-20070529-C00017.png)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2589664A (en) * 1949-08-30 1952-03-18 Airborne Instr Lab Inc Antenna system
US2591486A (en) * 1949-12-31 1952-04-01 Rca Corp Electromagnetic horn antenna
US2649575A (en) * 1951-10-20 1953-08-18 Gen Precision Lab Inc Microwave hollow guide power divider
US2727232A (en) * 1952-07-19 1955-12-13 North American Aviation Inc Antenna for radiating elliptically polarized electromagnetic waves
US2742640A (en) * 1951-03-21 1956-04-17 Gen Electric Co Ltd Aerial systems
US2824305A (en) * 1954-09-30 1958-02-18 Richard F Ohlemacher Microwave antenna feed
US2832955A (en) * 1953-03-24 1958-04-29 Jasik Henry Antenna system
US3155925A (en) * 1961-12-18 1964-11-03 Airtron Inc Axial fed nu-sided cavity with triggering control for selectively energizing individual faraday rotator switches for multi-channel communication
EP1258948A2 (en) * 2001-05-17 2002-11-20 Hitachi Kokusai Electric Inc. Semicircular radial antenna

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2844878A (en) * 1956-02-15 1958-07-29 Zwierzynski Alexander Combined micrometer instrument
DE2604210C3 (de) * 1976-02-04 1981-07-09 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Hohlleitererreger für eine Parabolantenne

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2589664A (en) * 1949-08-30 1952-03-18 Airborne Instr Lab Inc Antenna system
US2591486A (en) * 1949-12-31 1952-04-01 Rca Corp Electromagnetic horn antenna
US2742640A (en) * 1951-03-21 1956-04-17 Gen Electric Co Ltd Aerial systems
US2649575A (en) * 1951-10-20 1953-08-18 Gen Precision Lab Inc Microwave hollow guide power divider
US2727232A (en) * 1952-07-19 1955-12-13 North American Aviation Inc Antenna for radiating elliptically polarized electromagnetic waves
US2832955A (en) * 1953-03-24 1958-04-29 Jasik Henry Antenna system
US2824305A (en) * 1954-09-30 1958-02-18 Richard F Ohlemacher Microwave antenna feed
US3155925A (en) * 1961-12-18 1964-11-03 Airtron Inc Axial fed nu-sided cavity with triggering control for selectively energizing individual faraday rotator switches for multi-channel communication
EP1258948A2 (en) * 2001-05-17 2002-11-20 Hitachi Kokusai Electric Inc. Semicircular radial antenna
EP1258948A3 (en) * 2001-05-17 2004-04-07 Hitachi Kokusai Electric Inc. Semicircular radial antenna
US6930647B2 (en) 2001-05-17 2005-08-16 Hitachi Kokusai Electric Inc. Semicircular radial antenna

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Publication number Publication date
BE465944A (US07223432-20070529-C00017.png)
CH249519A (de) 1947-06-30

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