US2762044A - Slot aerials - Google Patents

Slot aerials Download PDF

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Publication number
US2762044A
US2762044A US305658A US30565852A US2762044A US 2762044 A US2762044 A US 2762044A US 305658 A US305658 A US 305658A US 30565852 A US30565852 A US 30565852A US 2762044 A US2762044 A US 2762044A
Authority
US
United States
Prior art keywords
slot
rods
cylinder
radiation pattern
wavelength
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
US305658A
Other languages
English (en)
Inventor
Boys Thomas Rex
Martin John Ernest
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.)
Marconis Wireless Telegraph Co Ltd
STC PLC
BAE Systems Electronics Ltd
Original Assignee
Marconi Co Ltd
Standard Telephone and Cables PLC
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, Standard Telephone and Cables PLC filed Critical Marconi Co Ltd
Application granted granted Critical
Publication of US2762044A publication Critical patent/US2762044A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01Q13/10—Resonant slot antennas
    • H01Q13/12—Longitudinally slotted cylinder antennas; Equivalent structures

Definitions

  • the present invention relates to slot aerials of the type comprising an elongated, hollow conducting body in which a slot is formed, the longitudinal axis of the slot being substantially parallel to the longitudinal axis of the hollow conducting body.
  • the hollow conducting body is usually of circular cross section but it will be understood that the cross section of the conducting body may be of any one of a number of shapes such as square or rectangular.
  • Aerials of the type specified are normally used to radiate horizontally polarised waves, in which case the hollow body is arranged with its longitudinal axis vertical.
  • the electrical length of the slot is approximately half a wavelength long at the operating frequency and more than one such slot may be used, the several slots being arranged in a vertical line.
  • the object in using more than one slot is to increase the power radiated in the horizontal directions and thus improve the aerial directivity.
  • the same object can be achieved within limits by using a single longer slot but this is sometimes inconvenient from a mechanical point of view.
  • the conducting body is a cylinder and it is required to produce a substantially circular radiationfpattern in the horizontal plane it is usual to make the diameter of the cylinder equal to a small fraction of a wavelength at the operating frequency. It is sometimes required, however, to provide a horizontal radiation pattern which is other than circular. For example Where two transmitters are operating on the same frequency or on closely spaced frequencies, it may become necessary, to avoid interference, to restrict the power radiated from at least one of the transmitters in the direction of the other without reducing the power radiated in other directions. Furthermore, when the radiated signals occupy a large frequency band as in television, it is necessary to maintain the aforesaid reduction in power in the same proportion over the whole of the requisite frequency band.
  • One object of the present invention is to provide an improved slot aerial of the type specified which can be arranged to provide a non-circular radiation pattern whose shape remains substantially unchanged over a substantial band of frequencies.
  • Another object of the an improved slot aerial of the type specified whose input admittance remains substantially constant over a substantial band of frequencies.
  • a slot aerial of the type specified comprises two or more conductors disposed on or near the hollow conducting body, the longitudinal axis of the conductors being disposed substantially at right angles to the longitudinal axis of the conducting body.
  • the number, length and spacing of the conductors from one another and from the hollow conducting body is dependent upon the shape of radiation pattern required.
  • the conductors may be energised solely by incident radiation from the slot or they may be energised directly from a transmitter by way of a transmission line, the same transmitter being used to energise the slot.
  • Figure 1 is a diagrammatic elevation of one embodiment of the invention
  • Figure 2 is a cross-section taken at 22 in Figure 1
  • Figure 3 is a diagrammatic elevation of a second embodiment of the invention.
  • Figure 4 is a cross-section taken at 4-4 in Figure 3.
  • avertical metal cylinder 10 whose diameter is approximately wavelength at the operating frequency has a straight slot 11 formed therein parallel to the axis of the cylinder and about two wave lengths long.
  • a transmitter shown diagrammatically at 12 is concerned by a balanced feeder 13 to the centre of the slot, the two conductors of the feeder being connected to the centres of the two longitudinal edges respectively or" the slot.
  • Each of four horizontal rods 14 to 17 of insulating material has one of its ends fixed to the cylinder 10 and the other ends of the rods 14 to 17 carry four rods 18 to 21 respectively of conducting material.
  • the axes of the four separating rods 14 to 17 lie in a common vertical plane which includes the axis of the cylinder 10 and the centre'line of the slot 11 and the rods are equally spaced in that vertical plane by half a wavelength at the operating frequency.
  • the supporting rods are fixed to the cylinder at four points respectively along the line on the cylinder where the said vertical plane cuts the cylinder.
  • Each of the supporting rods 14 to 17 is a quarter of a wavelength long at the operating frequency.
  • the axes of the rods 18 to 21 fixed to the supporting rods 14 to 17 are also horizontal and lie in a common vertical plane which is at right angles to the plane containing the axes of the supporting rods 14 to 17.
  • the junctions between the rods 18 to 21 and the supporting rods 14 to 17 respectively are at the centres of the rods 18 to 21 respectively.
  • the shape of the horizontal radiation pattern can be varied substantially by varying the length of the rods 18 to 21.
  • the length of the rods 18 to 21 is approximately equal to 0.6 of a wavelength the radiation pattern is of the aforesaid cardioid shape and the ratio of the maximum field strength of the present invention is to provide minimum, field strength may be about 4:1.
  • the radiation pattern remains of substantially con: stant shape and the input admittance of the aerial is of a form suitable for matching to a transmission line Within close. limits over a substantial band of frequencies for example. i4% of the mid-band frequency;
  • the cylinder 10, transmitter 12 and feeder 13 are identical with those shown in Figures l and 2..
  • the rods 14 to 21 of Figures 1 and 2 are, however, replaced by 8 rods of conducting material of which 4 are shown at 22 to 25 in Figure 3 and a fifth is shown at 23 in Figure. 4.
  • the rods in Figures 3 and 4. are arranged in coaxial pairs such as 23, and 23' in Figure 4 and are fixed to and project from opposite sides? of the cylinder.
  • The. aXes f. the rodsv are horizontal and lie in a common vertical plane which contains the. axis of. the cylinder and lies at. right angles to the plane containing the axis of the cylinder and the centre line of the slot.
  • each rod on each Side of, the cylinder are. spaced by half a wavelength and; each rod may have a length of 0.2 of a wavelength.
  • Such an arrangement is suitable for producing a horizontal radiation pattern of the same shape as that produced by a slottedcylinder whose diameter is a large fraction of the operating wavelength. The. inconvenience of having a; large mechanical structure is however avoided.
  • the invention may be used in both transmitting and receiving aerials.
  • Figs. 1 and 2 it is desired to utilize the conducting rods as active rather than as passive elements, they may be coupled to the same feeder as the slot provided that a. suitable impedance matching device is employed between the feeder and the rods.
  • a suitable impedance matching device will be apparent to those skilled in the art.
  • An aerial comprising a plurality of conductors mounted ona hollow conducting body, including a slot extending along one surface of the body, the conductors being of equal lengths and insulated from the hollowbody, the mid points or the conductors lying along a line which is parallel to the longitudinal axis of the hollow body and is in a plane which includes the longitudinal axis of the hollow conducting body and the centre line of the slot, and is spaced from the hollow body in a direction proceeding from the centre line of the slot through the longitudinal axis of the hollow body, the

Landscapes

  • Waveguide Aerials (AREA)
  • Meter Arrangements (AREA)
US305658A 1951-08-21 1952-08-21 Slot aerials Expired - Lifetime US2762044A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB19736/51A GB737873A (en) 1951-08-21 1951-08-21 Improvements in and relating to slot aerials

Publications (1)

Publication Number Publication Date
US2762044A true US2762044A (en) 1956-09-04

Family

ID=10134335

Family Applications (1)

Application Number Title Priority Date Filing Date
US305658A Expired - Lifetime US2762044A (en) 1951-08-21 1952-08-21 Slot aerials

Country Status (5)

Country Link
US (1) US2762044A (en, 2012)
BE (1) BE513628A (en, 2012)
DE (1) DE957857C (en, 2012)
FR (1) FR1061569A (en, 2012)
GB (1) GB737873A (en, 2012)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7123200B1 (en) * 1990-05-02 2006-10-17 Nortel Networks Limited Sea surface antenna

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1218560B (de) * 1960-11-25 1966-06-08 Marcel Portenseigne Sa Ets Breitbandige Schlitzantenne fuer sehr kurze Wellen
KR101944340B1 (ko) * 2012-12-28 2019-01-31 엘지디스플레이 주식회사 슬롯 안테나와 이를 이용한 정보 단말 장치

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234293A (en) * 1939-09-19 1941-03-11 Rca Corp Antenna system
US2510290A (en) * 1947-06-10 1950-06-06 Rca Corp Directional antenna
US2611867A (en) * 1946-08-31 1952-09-23 Alford Andrew Slotted winged cylindrical antenna

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234293A (en) * 1939-09-19 1941-03-11 Rca Corp Antenna system
US2611867A (en) * 1946-08-31 1952-09-23 Alford Andrew Slotted winged cylindrical antenna
US2510290A (en) * 1947-06-10 1950-06-06 Rca Corp Directional antenna

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7123200B1 (en) * 1990-05-02 2006-10-17 Nortel Networks Limited Sea surface antenna

Also Published As

Publication number Publication date
FR1061569A (fr) 1954-04-13
DE957857C (de) 1957-01-17
GB737873A (en) 1955-10-05
BE513628A (en, 2012)

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