US3646479A - Directional coupler comprising different transmission lines on opposite sides of dielectric board - Google Patents

Directional coupler comprising different transmission lines on opposite sides of dielectric board Download PDF

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Publication number
US3646479A
US3646479A US103061A US3646479DA US3646479A US 3646479 A US3646479 A US 3646479A US 103061 A US103061 A US 103061A US 3646479D A US3646479D A US 3646479DA US 3646479 A US3646479 A US 3646479A
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United States
Prior art keywords
coupling
gap
transmission lines
line
lines
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Expired - Lifetime
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US103061A
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English (en)
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Frans Christiaan De Ronde
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P5/00—Coupling devices of the waveguide type
    • H01P5/12—Coupling devices having more than two ports
    • H01P5/16—Conjugate devices, i.e. devices having at least one port decoupled from one other port
    • H01P5/18—Conjugate devices, i.e. devices having at least one port decoupled from one other port consisting of two coupled guides, e.g. directional couplers

Definitions

  • ABSTRACT A reciprocal directional coupling comprising a strip line pro- [52] U5. M vided on a dielectric upporting plate and a line provided [51] f CL i 1 5/14 on the opposite surface so that the longitudinal axes of the [58] Fleld ofSearch 333/10, 84 M transmission lines cross each m at a small angle so that a m .wide, effective frequency bandwidth is obtained.
  • the invention relates to a reciprocal directional coupling.
  • Such directional couplings usually comprise two relatively coupled transmission lines or waveguides whose four terminals in total form coupling points.
  • Directional couplings have the property that wave energy fed to one terminal of one transmission line can be conducted away at least partly only via one of the terminals of the other transmission line and cannot be conducted via the other terminal of the other transmission line.
  • wave energy fed to the other terminal of the first transmission line can be coupled out only via the other terminal of the second transmission line.
  • Such directional couplings are employed, for example, for coupling out energy from a continuous transmission line, for example, in television distribution systems. ln this case one of the coupling points may be connected to a television receiver and a further coupling point may be connected to a load resistor, in which normally no energy is dissipated. In general, this resistor is integral with the directional coupling.
  • phase difierence will appear between the waved coupled over at the respective places along the line so that as a whole the coupling intimately depends upon frequency, which means that the coupling is at a maximum when the length of the conductors is an odd multiple of one-quarter wavelength and is equal to zero when the length is an even multiple of one-quarter wavelength.
  • the invention provides a directional coupling whose coupling factor is substantially constant in a very wide frequency range, for example, between 1 and gl-lz.
  • the directional coupling according to the invention comprises two relatively coupled transmission lines arranged on opposite faces of a dielectric support, the coupling points being formed by the terminals of the transmission lines.
  • one transmission line is formed by a strip line constituted by an electric conductor on one surface of the support, whereas the other transmission line is a gap line formed by the gap between two electrically conductive faces on the other side of the support, while the longitudinal axis of the conductor, at least in the proximity of the gap, is at a small angle differing fromzero to the longitudinal axis of the gap.
  • the effect of the directional coupling is based on a difierence of properties between strip lines and. gap lines, which are known per se.
  • both the electrical and mag netic lines of force mainly extend in planes at right angles to the longitudinal axes of the transmission lines.
  • Gap lines are essentially symmetric transmission lines and coupling occurs between the two conductive faces on either side of the gap.
  • the coupling is destructive, like in the aforesaid waveguide directional coupling, which means that due to the phase differences resulting from differences in transit time the various partial couplings counteract each other so that the waves will cancel each other.
  • the coupling in the reverse direction is of a periodical character as a function of the frequency and at the maximum it is equal to the energy coupled over a coupling length of one-quarter wavelength. According as the angle between the two transmission lines is smaller and hence the coupling trajectory is longer (particularly a higher number of wavelengths); the ovcrcoupled energy per quarter wavelength will be lower and hence the coupling in the undesired direction is weaker.
  • the drawing shows schematically one embodiment of a. directional coupling in accordance with the invention.
  • FIG. 1 is a plan view on the side of the gap line
  • - FlGS. 2a and 2b are partial cross-sectional views at various. places along the line at right angles to the longitudinal axis.
  • a sheetlike support 1 of dielectric material is provided with a thin conductive layer 2 having a narrow gap 3.
  • the width of this gap may be a few 10 microns.
  • a conductive strip 4 is provided, which crosses the gap 3 at a very small angle so that a long coupling trajectory is formed.
  • the gap 3 terminates at both ends in recessesS and 6.
  • the gap transmission line 3 is coupled at the terminals with concentric transmission lines 7 and 8, the outer sheaths and the inner conductors of which are connected to the conductive layer 2 at points on either side of the gap 3.
  • the recesses 5 and 6 form a high impedance-between the coupling points.
  • the tap may extend as far as to the edges of the conductive layer 2.
  • the terminals of the strip line 4 may be coupled with concentric conductors (not'shown), the inner conductors being connected to the terminals of the strip 4 and the outer conductors being connected to the conductive layer 2.
  • the terminals may be coupled with a different type of transmission line, for example, a difi'erent strip line.
  • the coupling factor was equal to about 'l0 db. in a frequency range from 1 to 12 gHz.
  • the coupling factor depends inter alia upon the thickness of 10 the dielectric intermediate layer. If this layer is sufficiently thin, a coupling factor of 3 db. can be easily attained.
  • the coupling length is preferably greater than 5 wavelengths.
  • a reciprocal directional coupling comprising two relatively coupled transmission lines arranged on opposite faces of a dielectric support, the coupling points being formed by the terminals of the transmission lines, characterized in that one transmission line is a strip line formed by an electric conductor on one face of the support and the other transmission line is a gap line formed by the gap between two electrically conductive surfaces on the other side of the support, the longitudinal axis of the conductor, at least in the proximity of the gap, being at a small angle differing from zero to the longitudinal axis of the gap.

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  • Waveguides (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Waveguide Aerials (AREA)
US103061A 1970-02-14 1970-12-31 Directional coupler comprising different transmission lines on opposite sides of dielectric board Expired - Lifetime US3646479A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7002118A NL7002118A (enExample) 1970-02-14 1970-02-14

Publications (1)

Publication Number Publication Date
US3646479A true US3646479A (en) 1972-02-29

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ID=19809337

Family Applications (1)

Application Number Title Priority Date Filing Date
US103061A Expired - Lifetime US3646479A (en) 1970-02-14 1970-12-31 Directional coupler comprising different transmission lines on opposite sides of dielectric board

Country Status (6)

Country Link
US (1) US3646479A (enExample)
JP (1) JPS5139506B1 (enExample)
DE (1) DE2102554C3 (enExample)
FR (1) FR2079432B1 (enExample)
GB (1) GB1324577A (enExample)
NL (1) NL7002118A (enExample)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114204241A (zh) * 2021-12-07 2022-03-18 杭州电子科技大学 微带-开路槽线耦合双频带90度定向耦合器

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2838317C2 (de) * 1978-09-01 1984-03-29 Siemens AG, 1000 Berlin und 8000 München Richtungskoppler
CN104078739A (zh) * 2014-07-29 2014-10-01 电子科技大学 一种基于石墨烯的定向耦合器

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2914766A (en) * 1955-06-06 1959-11-24 Sanders Associates Inc Three conductor planar antenna

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114204241A (zh) * 2021-12-07 2022-03-18 杭州电子科技大学 微带-开路槽线耦合双频带90度定向耦合器
CN114204241B (zh) * 2021-12-07 2022-10-21 杭州电子科技大学 微带-开路槽线耦合双频带90度定向耦合器

Also Published As

Publication number Publication date
DE2102554A1 (de) 1971-09-02
NL7002118A (enExample) 1971-08-17
JPS5139506B1 (enExample) 1976-10-28
DE2102554C3 (de) 1979-03-22
FR2079432A1 (enExample) 1971-11-12
GB1324577A (en) 1973-07-25
DE2102554B2 (de) 1978-07-20
FR2079432B1 (enExample) 1976-05-28

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