US3909757A - Leaky coaxial cable - Google Patents

Leaky coaxial cable Download PDF

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Publication number
US3909757A
US3909757A US448680A US44868074A US3909757A US 3909757 A US3909757 A US 3909757A US 448680 A US448680 A US 448680A US 44868074 A US44868074 A US 44868074A US 3909757 A US3909757 A US 3909757A
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US
United States
Prior art keywords
coaxial cable
leaky coaxial
cable
conductor
inner conductor
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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
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US448680A
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English (en)
Inventor
Yoshio Miyamoto
Toshiyuki Ikemiya
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Sumitomo Electric Industries Ltd
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Sumitomo Electric Industries Ltd
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Publication date
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Publication of US3909757A publication Critical patent/US3909757A/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
    • H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/203—Leaky coaxial lines

Definitions

  • ABSTRACT A leaky coaxial cable wherein the inner conductor is helically wound with its Winding direction reversed alternately at a predetermined interval which is approximately equal to H2 of the wave length of the operating frequency and the outer conductor is a conductor tube having a gap or straight array of slots provided along the cable axis.
  • the leaky coaxial cable of the present invention which is installed horizontally, leaks out a vertically polarized leaky wave which is very suitable for use in radio communication systems.
  • the present invention relates to a leaky coaxial cable used forradidcomm-unication systems.
  • a leaky coaxial cable is'ordinally used to overcome the difficulty.
  • FIG. 1 denotes an outer corrugated conductor generally having slots 2,, 2 in the axial direction with apredetermined slot periodicity, each slot being slanted with a predetermined angle with respect to the cable axis, and 5. denotes an inner cond t 1 I '5 Y
  • the radio communication wave energy propagates in the coaxial cable and apart of it leaks out from'the slot array of the horizontally installed'leaky coaxial cable.
  • the leaked wave is polarized vertically andcouples with the antenna of a receiver.
  • the essential point in the construction of a cable of this kind is that the slot shape and'slot pitch must be made 'with a high degree of precision.
  • the outer conductor is usually made of thin-corrugated aluminum plate.
  • In thelnianufa'c'turin'g method for such aleaky 'coaxial cablei 'th'e r e" are known processes of perforating the slots at a predetermined interval in a thin metal band. of corrugating the plate in such a manner that straight small parallel ridges are produced in the direction lateral to the metal band.
  • the adjacent slots must have a predetermined precise interval and each of the slots must have a predetermined slot angle with respect to the cable axis with the band in its corrugated state.
  • the corrugated plate is bent longitudinally so as to make a tube including the inner conductor, and a plastic sheath is applied over the coaxial structure.
  • the conventional leaky coaxial cable as shown in FIG. 1 has a great disadvantage in manufacturing cost.
  • the leaky coaxial cable of the present invention is manufactured very economically.
  • the transmission properties of the cable of the present invention also are not different from those of the conventional ones.
  • the leaky coaxial cable may be broadly used for service in weak field areas of radio communication systems, for example, CATV systems and vehicle communication systems.
  • FIG. 1 isjan obliqueview with portions removed of a leaky cable of the prior art.
  • FIG. 2 is an oblique view with portions removed of the leaky coaxial cable of the present invention.
  • FIG. 3 (a) is an oblique view ofthe inner conductor of the leaky coaxial cable with the current distribution thereon diagrammatically illustrated.
  • FIG. 3 (b) is an oblique view of the outer conductor of the leaky coaxial cable of the present invention with the current distribution thereon diagrammatically illustrated.
  • FIG. 3 (c) is an oblique view illustrating another type of outer conductor for the leaky coaxial cable of the present invention.
  • FIG. 2 a slant view of the leaky coaxial cable is shown with the outer conductor 3 having gap means provided by gap 4 is continuous in the axial di-' rection of the cable and with an inner conductor 5 which is made by helically winding a suitable strip conductor and reversing its winding direction alternately at a predetermined periodicity d.
  • FIGS. 3 (a) and (b) show drawings for assisting in the explanation the principle of the leaky coaxial cable of the present invention.
  • FIG. 3 (a) shows an inner conductor 5' which is divided into sections 5,, 5 each of a predetermined length d. In each section, the conductor wire is wound helically at the same pitch and its winding direction is reversed at each adjacent section. The length d of each section is selected to be approximately one-half of the wave length of the operating frequency in the coaxial cable.
  • the currents distributed on each section 5,, 5 are shown by 6,, 6 in FIG. 3 ((1). Since the length of each section is approximately equal to one-half of the wave length in the coaxial cable, the current directions 6,, 6 are reversed from section to section.
  • the magnetic fields generated by the currents 6,, 6 at sections 5,, 5 are shown by 7,, 7 respectively.
  • the directions of the magnetic fields 7,, 7 are not reversed from section to section, because the direction of the current is reversed from section to section but the direction of winding of the helical inner conductor is also reversed from section to section.
  • FIG. 3 (b) shows an outer conductor 3 having gap means provided by gap 4 extending straight in the axial direction in parallel with the cable axis.
  • the width of the gap 4 is sufficiently smaller than the operating wave length.
  • the magnetic fields 7,, 7 induce respectively induced currents 8,, 8 in the outer conductor and at the gap 4 flowing circumferentially in the same direction.
  • the induced currents 8,, 8 at the gap 4 radiates a circumferentially polarized wave which is very suitable for a radio communication system. There are, however, no induced currents in the vicinity of the points where the winding direction of the inner conductor is reversed.
  • the leaky coaxial cable which consists of the combination of the inner conductor as shown in FIG. 3 (a) and the outer conductor with gap means provided by a straight array of slots extending in parallel with the cable axis as shown in FIG. 3 (c), is equally as good for use in place of such leaky coaxial cables having the outer conductor as shown in FIG. 3(b).
  • 9 9 indicate the straight slots posi tioned in the axial direction and corresponding to the sections 5,, 5 of the inner conductor respectively.
  • the length of each slot is slightly shorter than the periodicity d and the width of each of the slots is the same and sufficiently smaller than the operating wavelength.
  • the leaky coaxial cable according to the present invention can be used effectively for mobile radio bands utilizing VHF, UHF, etc.
  • a flexible body of magnetic material or of insulating material therein having a magnetic material may be used as a winding mandrel for the central helical conductor with the object of further improving the excitation efficiency of the opening of the outer conductor by enhancing the contraction effect of the wavelength in the waveguide.
  • the present invention makes it possible to obtain a leaky coaxial cable which leaks out a vertically polarized wave which is very suitable for use in a radio communication system.
  • the structure comprises an inner conductor of a helically wound wire whosc winding direction is reversed alternately at a predetermined length and an outer conductor having an opening such as either a straight gap or straight array of slots in the direction of the cable axis.
  • the leaky coaxial cable of the present invention has a very stable and simple mechanical structure so that it has good productivity with high precision in manufacture and is easy to handle for installation and maintenance.
  • the leaky coaxial cable further makes it very easy to regulate the amount of leaky wave energy per unit length radiating from the opening by partially shielding the radiation area of the opening with a conductor plate such as a metal plate.
  • a conductor plate such as a metal plate.
  • the helical structure of the inner conductor may be made up of two or more parallel conductor wires or strips instead of a single wire or strip as shown in FIG. 3 (a).
  • a leaky coaxial cable comprising an inner conductor of at least one helically wound conductor with its winding direction reversed alternately at a predetermined interval approximately equal to one-half of the wave length of the operating frequency, and a coaxial outer conductor having gap means extending along in parallel with the cable axis to leak wave energy propagating in the cable.
  • said gap means consists of an end-to-end series of spaced slots of the same length which is slightly smaller than the length of the winding reversion of said inner conductor, the space between said slots being positioned at the reversal points of winding of said inner conductor.

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  • Waveguide Aerials (AREA)
  • Near-Field Transmission Systems (AREA)
US448680A 1973-03-13 1974-03-06 Leaky coaxial cable Expired - Lifetime US3909757A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48029254A JPS49116587A (enExample) 1973-03-13 1973-03-13

Publications (1)

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US3909757A true US3909757A (en) 1975-09-30

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US448680A Expired - Lifetime US3909757A (en) 1973-03-13 1974-03-06 Leaky coaxial cable

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US (1) US3909757A (enExample)
JP (1) JPS49116587A (enExample)
GB (1) GB1415485A (enExample)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2381399A1 (fr) * 1977-02-22 1978-09-15 Aeg Telefunken Kabelwerke Cable coaxial haute frequence et son procede de fabrication
US4157518A (en) * 1977-07-27 1979-06-05 Belden Corporation Leaky coaxial cable having shield layer with uniform gap
US4495503A (en) * 1982-02-19 1985-01-22 Morman William H Slow wave antenna
FR2732820A1 (fr) * 1995-04-07 1996-10-11 Inst Scient De Service Public Ligne haute frequence rayonnante
US5809429A (en) * 1995-09-22 1998-09-15 Andrew Corporation Radiating coaxial cable and radio communication system using same
US5936203A (en) * 1997-10-15 1999-08-10 Andrew Corporation Radiating coaxial cable with outer conductor formed by multiple conducting strips
US6480163B1 (en) 1999-12-16 2002-11-12 Andrew Corporation Radiating coaxial cable having helically diposed slots and radio communication system using same
US6624358B2 (en) 2001-12-13 2003-09-23 Andrew Corporation Miniature RF coaxial cable with corrugated outer conductor
EP1657828A1 (de) * 2004-11-10 2006-05-17 Beumer Maschinenfabrik GmbH & Co. KG Vorrichtung mit einem entlang einer Fahrstrecke bewegbaren Basissystem
US8059045B1 (en) 2008-08-18 2011-11-15 Hrl Laboratories, Llc Antenna having an impedance matching section for integration into apparel
US8180183B1 (en) 2008-07-18 2012-05-15 Hrl Laboratories, Llc Parallel modulator photonic link
US8750709B1 (en) 2008-07-18 2014-06-10 Hrl Laboratories, Llc RF receiver front-end assembly
US8995838B1 (en) 2008-06-18 2015-03-31 Hrl Laboratories, Llc Waveguide assembly for a microwave receiver with electro-optic modulator
US9335568B1 (en) 2011-06-02 2016-05-10 Hrl Laboratories, Llc Electro-optic grating modulator
CN106340703A (zh) * 2016-11-16 2017-01-18 江苏亨鑫科技有限公司 一种高隔离三同轴漏泄同轴电缆
US11008841B2 (en) 2017-08-11 2021-05-18 Acceleware Ltd. Self-forming travelling wave antenna module based on single conductor transmission lines for electromagnetic heating of hydrocarbon formations and method of use
US11729870B2 (en) 2019-03-06 2023-08-15 Acceleware Ltd. Multilateral open transmission lines for electromagnetic heating and method of use
US11773706B2 (en) 2018-11-29 2023-10-03 Acceleware Ltd. Non-equidistant open transmission lines for electromagnetic heating and method of use

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5717411A (en) * 1995-04-19 1998-02-10 Andrew Corporation Radiating waveguide and radio communication system using same
CN110854519B (zh) * 2019-11-23 2022-08-12 武汉市联华飞创科技有限公司 一种共形体天线装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781725A (en) * 1972-05-04 1973-12-25 Sumitomo Electric Industries Leaky coaxial cable

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5522505B2 (enExample) * 1972-04-07 1980-06-17

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781725A (en) * 1972-05-04 1973-12-25 Sumitomo Electric Industries Leaky coaxial cable

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2381399A1 (fr) * 1977-02-22 1978-09-15 Aeg Telefunken Kabelwerke Cable coaxial haute frequence et son procede de fabrication
US4157518A (en) * 1977-07-27 1979-06-05 Belden Corporation Leaky coaxial cable having shield layer with uniform gap
US4495503A (en) * 1982-02-19 1985-01-22 Morman William H Slow wave antenna
FR2732820A1 (fr) * 1995-04-07 1996-10-11 Inst Scient De Service Public Ligne haute frequence rayonnante
BE1010528A5 (fr) * 1995-04-07 1998-10-06 Inst Scient De Service Public Ligne haute frequence rayonnante.
US5809429A (en) * 1995-09-22 1998-09-15 Andrew Corporation Radiating coaxial cable and radio communication system using same
US5936203A (en) * 1997-10-15 1999-08-10 Andrew Corporation Radiating coaxial cable with outer conductor formed by multiple conducting strips
US6480163B1 (en) 1999-12-16 2002-11-12 Andrew Corporation Radiating coaxial cable having helically diposed slots and radio communication system using same
US6624358B2 (en) 2001-12-13 2003-09-23 Andrew Corporation Miniature RF coaxial cable with corrugated outer conductor
EP1657828A1 (de) * 2004-11-10 2006-05-17 Beumer Maschinenfabrik GmbH & Co. KG Vorrichtung mit einem entlang einer Fahrstrecke bewegbaren Basissystem
US8995838B1 (en) 2008-06-18 2015-03-31 Hrl Laboratories, Llc Waveguide assembly for a microwave receiver with electro-optic modulator
US8180183B1 (en) 2008-07-18 2012-05-15 Hrl Laboratories, Llc Parallel modulator photonic link
US8750709B1 (en) 2008-07-18 2014-06-10 Hrl Laboratories, Llc RF receiver front-end assembly
US8059045B1 (en) 2008-08-18 2011-11-15 Hrl Laboratories, Llc Antenna having an impedance matching section for integration into apparel
US9335568B1 (en) 2011-06-02 2016-05-10 Hrl Laboratories, Llc Electro-optic grating modulator
CN106340703A (zh) * 2016-11-16 2017-01-18 江苏亨鑫科技有限公司 一种高隔离三同轴漏泄同轴电缆
CN106340703B (zh) * 2016-11-16 2022-01-25 江苏亨鑫科技有限公司 一种高隔离三同轴漏泄同轴电缆
US11008841B2 (en) 2017-08-11 2021-05-18 Acceleware Ltd. Self-forming travelling wave antenna module based on single conductor transmission lines for electromagnetic heating of hydrocarbon formations and method of use
US11773706B2 (en) 2018-11-29 2023-10-03 Acceleware Ltd. Non-equidistant open transmission lines for electromagnetic heating and method of use
US11729870B2 (en) 2019-03-06 2023-08-15 Acceleware Ltd. Multilateral open transmission lines for electromagnetic heating and method of use
US11991810B2 (en) 2019-03-06 2024-05-21 Acceleware Ltd. Multilateral open transmission lines for electromagnetic heating and method of use

Also Published As

Publication number Publication date
GB1415485A (en) 1975-11-26
JPS49116587A (enExample) 1974-11-07
DE2412139A1 (de) 1974-09-26
DE2412139B2 (de) 1975-06-26

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