EP0134688B1 - Antenne losange - Google Patents

Antenne losange Download PDF

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Publication number
EP0134688B1
EP0134688B1 EP19840305136 EP84305136A EP0134688B1 EP 0134688 B1 EP0134688 B1 EP 0134688B1 EP 19840305136 EP19840305136 EP 19840305136 EP 84305136 A EP84305136 A EP 84305136A EP 0134688 B1 EP0134688 B1 EP 0134688B1
Authority
EP
European Patent Office
Prior art keywords
aerial
resistor
arms
rhombic
transmission line
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
Application number
EP19840305136
Other languages
German (de)
English (en)
Other versions
EP0134688A1 (fr
Inventor
Eric John Patrick May
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.)
University of Exeter
Original Assignee
University of Exeter
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 University of Exeter filed Critical University of Exeter
Publication of EP0134688A1 publication Critical patent/EP0134688A1/fr
Application granted granted Critical
Publication of EP0134688B1 publication Critical patent/EP0134688B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength

Definitions

  • This invention relates to rhombic aerials for radio transmission and reception, and is more particularly applicable to the manner in which connections are made to such aerials.
  • a standard rhombic aerial consists of two active elements in the form of wires having a section in which they are close together and a section in which the wires from two arms which first diverge at the same angle and then converge to a connection point, so that the latter section is in the shape of a rhombus.
  • Such rhombic aerials are disclosed in e.g. US-A-2285565, pages 4-30 to 4-35 of "Antenna Engineering Handbook” edited by H. Jasik published by McGraw Hill in New York in 1962, and pages 8 and 9 of the 1949 edition of "Microwave Antenna Theory and Design” edited by S. Silver.
  • a resistor In a rhombic aerial it is important that only travelling waves are generated, and to suppress standing waves it is usual for there to be a resistor connecting the wires at the connection point.
  • This resistor which usually has a resistance of about 6000 to 8000, absorbs the electrical power that the aerial has not converted to a travelling wave and would otherwise set up a standing wave.
  • the power dissipated by the resistor may be up to 60% of the power input to the aerial, but despite the disadvantage of power loss, the rhombic aerial is desirable because of its large bandwidth.
  • the inventor of the present application decided to use conductive tubes, bent at a suitable angle, to form the active elements of the rhombus.
  • the rigidity of the tubes enabled the aerial to be self- supporting.
  • the input transmission lines are in the form of a co-axial cable.
  • an aerial with tubular conductors was connected to a co-axial cable it was found that the outer conductor of the cable acted as an extension of the arm of the aerial to which it was connected, causing the performance of the aerial to deteriorate.
  • the present invention provides a rhombic aerial having two active elements in the form of conductive arms together forming a rhombus, one pair of adjacent ends of the active elements having a gap therebetween and each end of the pair being connected to a corresponding conductor of a transmission line, the other pair of adjacent ends of the active element being connected together by a resistor; characterized in that:
  • the resistor is tubular, the transmission line enters the resistor through a hole in the tube, and extends along a path from the resistor, substantially the whole of the path being at least partially enclosed within an active element, such that one of the conductors of the transmission line forms a part of that active element.
  • the improved efficiency of the rhombic aerial according to the present invention has the additional advantage that the value of the resistance of the resistor is less critical than in a standard rhombic aerial, and indeed satisfactory performance can be obtained with almost any resistance, although a resistance of about 200Q has been found to give good results.
  • the resistor is a tubular resistor with a hole through which passes the cable containing the conductors.
  • a tubular resistor may be fabricated by coating a hollow tubular insulator with conductive material.
  • the aerial in the figure comprises two arms formed by lengths of hollow tube 34, 35 having 130° bends 36 and arranged in rhombic form.
  • the angle of the bends 36 is an important factor in determining the performance of the aerial. The precise value selected depends on the wavelength and the aerial dimensions, but can be determined in a known way.
  • the bends 36 are spaced apart and supported by a plastics support member 38.
  • the tubes 34, 35 are connected together by a tubular resistor 42 and secured by a plastics nut 44 and bolt 46.
  • the tubular resistor 42 is preferably made by coating a hollow cylindrical insulator with an external coating of conductive material, e.g. by sputtering or printing.
  • the resistance of the resistor 42 may be selected to suit the use of the aerial, and in special cases may be infinite (an insulator) or negligibly small. Preferably, however, the resistance of the resistor 42 is between 100O. and 3000, and 2000 is often a suitable value.
  • the earth plane of this aerial is indicated by the dotted line 48. Unlike a prior art rhombic aerial, little power is dissipated by the resistor 42 when the aerial is used as a transmission aerial, and so the cooling methods used in the prior art may be unnecessary.
  • the signal feed to or from the aerial comprises a co-axial cable 18 which passes through a hole in the resistor 42, in the earth plane 48, and thence along the interior of the tube 34 to the connection points at the far end of the aerial.
  • the outer conductor of the cable is connected to the tube 34 e.g. by a suitable screw connected and the inner conductor 22 passes through an opening at the end of tube 34, extends across the gap between the ends of the tubes 34 and 35 and is connected to the tube 35 e.g. a suitable screw connector.
  • the illustrated embodiment may be modified without losing the advantages of the present invention.
  • the material of the arms can be any conductive material; metals such as copper or aluminium are suitable, and conductive plastics materials have been developed which are particularly advantageous, due to their lightness.
  • one of the conductors as the active element e.g. by removing the outer insulation from a co-axial cable or by using known strip conductors in which a pair of flat outer conductors are separated by insulation from an inner conductor.
  • the embodiment described above is supported by a support member 38 extending between the arms 34, 35. It would also be possible for the support member to extend from the resistor 42 to the connection end of the aerial, or even for the aerial to be supported from the tubular resistor itself.

Claims (4)

1. Antenne en losange ayant deux éléments actifs sous la forme de bras conducteurs (34, 35) formant ensemble un losange, une paire d'extrémités adjacentes des éléments actifs ayant un écartement entre elles et chaque extrémité de la paire étant connecté à un conducteur correspondant d'une ligne de transmission (18), les deux autres extrémités adjacentes de l'élément actif étant connectées par une résistance (42); caractérisée en ce que la résistance (42) est tubulaire, la ligne de transmission entre dans la résistance (42) par un trou dans le tube et s'étend le long d'un trajet à partir de la résistance (42), sensiblement la totalité du trajet étant au moins partiellement enfermée dans un élément actif, de manière que l'un des conducteurs de la ligne de transmission (18) fasse partie de cet élément actif.
2. Antenne en losange selon la revendication 1, où les bras (34, 35) sont des tubes conducteurs creux et la ligne de transmission traverse l'intérieur de l'un des tubes (34).
3. Antenne en losange selon la revendication 1, où les bras (34, 35) sont des gorges conductrices et la ligne de transmission passe dans la gorge de l'un des bras (34).
4. Antenne en losange selon la revendication 1, où l'un des éléments actifs est formé par un conducteur de la ligne de transmission (18).
EP19840305136 1983-07-28 1984-07-27 Antenne losange Expired EP0134688B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB838320420A GB8320420D0 (en) 1983-07-28 1983-07-28 Aerials
GB8320420 1983-07-28

Publications (2)

Publication Number Publication Date
EP0134688A1 EP0134688A1 (fr) 1985-03-20
EP0134688B1 true EP0134688B1 (fr) 1988-03-30

Family

ID=10546458

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840305136 Expired EP0134688B1 (fr) 1983-07-28 1984-07-27 Antenne losange

Country Status (3)

Country Link
EP (1) EP0134688B1 (fr)
DE (1) DE3470256D1 (fr)
GB (1) GB8320420D0 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2285565A (en) * 1931-02-03 1942-06-09 Bell Telephone Labor Inc Directive antenna
GB906301A (en) * 1960-05-28 1962-09-19 Standard Telephones Cables Ltd Improvement in radio-electric antennae
FR2298200A1 (fr) * 1975-01-17 1976-08-13 France Etat Doublet replie epais accordable dans une bande de frequence de deux octaves

Also Published As

Publication number Publication date
EP0134688A1 (fr) 1985-03-20
GB8320420D0 (en) 1983-09-01
DE3470256D1 (en) 1988-05-05

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