US2848696A - Electromagnetic wave transmission - Google Patents

Electromagnetic wave transmission Download PDF

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Publication number
US2848696A
US2848696A US416316A US41631654A US2848696A US 2848696 A US2848696 A US 2848696A US 416316 A US416316 A US 416316A US 41631654 A US41631654 A US 41631654A US 2848696 A US2848696 A US 2848696A
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United States
Prior art keywords
helix
wave
mode
transmission
tem
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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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US416316A
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English (en)
Inventor
Stewart E Miller
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AT&T Corp
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Bell Telephone Laboratories Inc
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Publication date
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US416316A priority Critical patent/US2848696A/en
Priority to FR1118560D priority patent/FR1118560A/fr
Priority to DEW15821A priority patent/DE1021044B/de
Priority to NL194602A priority patent/NL99249C/xx
Priority to GB7235/55A priority patent/GB764737A/en
Priority to BE536466D priority patent/BE536466A/xx
Application granted granted Critical
Publication of US2848696A publication Critical patent/US2848696A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P3/00—Waveguides; Transmission lines of the waveguide type
    • H01P3/12—Hollow waveguides
    • H01P3/13—Hollow waveguides specially adapted for transmission of the TE01 circular-electric mode

Definitions

  • This invention relates to electromagnetic wave transmission systems, and more particularly, to the transmission of the circular electric or TEM mode of wave propagation over long distances in a guided wave transmission system which either through choice or inherency does not follow a perfectly straight path.
  • the TEM mode is not the dominant mode supported in a circular wave guide, and consequently energy may be lost to other modes also capable of transmission therein.
  • an ideal wave guide which is perfectly straight, uniform and conducting, the propagation of TEM waves therethrough is undisturbed, but slight imperfections in the guide and especially curvature of the wave-guide axis may excite waves of other :modes and produce serious losses. These losses are attributed mainly to the fact that the bending of the guide produces a coupling between the desired TBM and other transmission modes, mainly the TMll mode.
  • the prior art has provided a large number of devices for negotiating bends or turns in the guides.
  • the phase velocity of the TMll mode (which is normally equal to that of the TEM mode) is changed relative to that of the TEM mode, to increase the relative differences in their propagation constants and to reduce the effective coupling therebetween.
  • a spaced ring line comprises a plurality of conductive ring-shaped sections, coaxially arranged, and successively spaced from each other at a uniform distance by insulating material.
  • the desired circular electric TEM mode produces circumferential currents which are not appreciahly interfered with by the ring structure.
  • the undesired modes produce predominantly longitudinal currents which are seriously affected by the division of the guide into the short cylindrical sections and therefore these modes are given velocities of propagation different from the TEM mode.
  • Lil 2,848,696' Patented Aug. 19, 1958 transmit circular electric mode wave energy over long distances without its degenerating into other modes.
  • the dissipative material comprises a cylinder-like casing having an inside surface contiguous with the outermost part of the helical conductor.
  • Fig. l diagrammatically illustrates a guided microwave communication system employing the circular electric wave and having a long distance transmission line of the type provided by the present invention
  • Figs. 2 and 3 illustrate the transverse electric and magnetic field patterns of the TEM and TMm waves, respectively;
  • Fig. 4 partially in cross section, illustrates the construction of a small section of transmission line in accordance with the present invention
  • Figs. 5 and 6 are cross-sectional views showing first and second alternative constructions of sections of transmission line in accordance with the invention.
  • Fig. 7 shows the structure and also one method of assembling the structure of another alternative embodiment of the invention.
  • a long distance guided microwave communication system is schematically shown.
  • the system is characterized as long to distinguish it from the short distances found in terminal equipment and to define a system in which the factor of transmission attenuation becomes relatively important.
  • the length of such a system would be measured in terms of thousands of feet and perhaps miles as opposed to several inches or a few feet in the terminal equipment.
  • This System comprises a terminal station 11 which may be a transmitter, or if this is an intermediate station, a repeater 11 which is to be connected to a receiver or subsequent repeater comprising station 12.
  • the circular electric TEol mode is the mode in which energy is transmitted between stations and since this mode is not usually produced or utilized directly in the components of a station, transducers 13 and 14 are interposed between stations V11 and 12 and the long distance transmission line 15.
  • Transducers 13 and 14 may be of any suitable well known ⁇ types for'converting TEM wave energy to and from a dominant wave mode conguration.
  • they may be structures of the types disclosed in United States Patent 2,656,513 granted to A. P. King, October 20, 1953, or of the copending applications of S. E. Millen'Serial No. 245,210, filed September 5, 1951, which on May 29, 19.56, issued as United VStates Patent 2,748,35Q, and S. E. Miller, Serial No. 357,665, led May 27, 19,53.
  • lLine, 15 is not completely straight along its entire length since in practical installation it is substantially impossible to maintain the line along a precisely straight path over a long distance. Intentional bends may also he included in order that the linev may follow right of ways .or turn corners. It is these bends that produce the characteristic moding or degeneration of the TEM into TMH wave power. As noted above, this moding is ascribed to the fact that these waves have substantially the same phase constants, i. e., phase velocity and wavelength and, therefore, interact Strongly in a manner analogous to coupled transmission lines.
  • Fig. 2 illustrates the distribution of the electric and magnetic fields in a transverse section of a circular conductive -wave guide supporting the TEol transmission mode.
  • This wave i s designated the circular electric type inasmuch as the electric eld, shown by the solid lines 16, consists of circular lines coaxial with the guide and lying transversely thereto Without any longitudinal ccmponents.
  • the transverse component of the magnetic field, indicated by the dotted lines 17, forms at variouspoints along the guide in a radial pattern.
  • the electric field intensity attains a maximum approximately half Way between the axis and surface of the guide and drops to zero at the surface.
  • the current ow associated with the TEO! wave is predominantly circular around the per riphery of the guide as illustrated in Fig. 2.V
  • the configuration of the transverse TMH mode is shown in Fis. .3 and is Similar t that 0f a Shielded ccnductor pair.
  • the magnetic field pattern is entirely transverse without any longitudinal components and is indicated by the dotted lines 13 encircling the respective poles P and P. Since the magnetic lines must form closed paths, they tend to spread out near the center of the guide and to crown close together at the inner surface mostly near the axis passing through poles P and P', thus inducing a considerable longitudinal conduction of current in the wall of the guide.
  • the direction of this current flow is shown conventionally by the symbols 19 and 20 on Fig. 3.
  • Fig. 4 shows in detail a short section of the transmission line 15 of Fig. 1.
  • line 15 comprises a conductor 41 wound in a helix having an internal diameter d.
  • Conductor 41 may be solid or stranded and may comprise a base metal such as iron or steel plated by a highly conductive material such as copper or silver.
  • Adjacent turns such as 42 or 43 of the helix are electrically insulated from each other, and this may be provided by a small air gap such as 44.
  • the pitch distance ot"V the helix i'.V e., the distance between Vthe center of turns 4,2 and 43, and therefore the pitch angle of the helix, should be as small as consistent with the aboveL mentioned insulating' requirement. This distance in all events must be less than one quarter wavelength and is kpreferably such that theY gap 44 between adjacent turns is less.- than.
  • gap 44 is exposed to electrically dissipative or lossy. material.
  • helix 41 This may bey done by'enclosing helix 41 in,y a 75 substantially equal to the outside diameter of helixV 41.
  • Casing 45 also serves as a protective and supporting structure for helix 41 and may therefore be either semi-rigid, forming a more or less permanent structure, or pliable, forming a flexible one.
  • Casing 45 may then be covered with'a nonfcorrosive conductive shield 46 which serves to protect the line from outside mechanical influences such as weather, moisture and insects and from electrical influences such as stray radiation from adjacent transmission lines.
  • lt is desirable that the cross Section of helix 41 be maintained as nearly circular as possible. This condition may be maintained by the resilience of casings 45 and 46. It may, however, be maintained by employing for the con ductor of helix 41 a spiral of spring steel plated by a highly conductive material. Thus the effect of the spring itself will maintain the desired circularity and shield 45 may be wound of overlapping, thin strips or may be made of a woven braid.
  • the inside diameter ci of helix 41 is related to the i diameter of the circular pipe guide which would transmit waves of the same frequency.
  • the diameter d must be greater than the critical or cut-off diameter for the TEM mode in a circular guide. is equal to 1.22%, where )to is the wavelength in free space of the longest wave in the transmission band.
  • Vpractice d might be in the range 1.25 to 1() times the smallcomponent of the wave is presented with a small reactance caused by the discontinuity:between adjacent turns. This reactance will have the eifect of changing the phase velocity of the total wave very slightly. Very little of the total TEM current willpass through the resistive material of casing 45 and therefore the attenuation constant of the TEM Wave is changed very little.
  • the TMm mode however, has a predominantly longitudinal current tlow along the wave-guiding path and will be seriously affected by the discontinuity between adjacent turns of helix 41. Not only is the phase constant of this mode increased by the ⁇ reactance of each discontinuity, but the longitudinal currents are forced to ow through the dissipative material of casing 45. lt may be shown that the amount of degeneration of the TEM mode into the TMll mode along a bent section of waveguide is proportional to the coeicient of coupling between these two modes along such bend and may be expressed C: RA.,
  • r is the radius of the circular wave-guiding path, )to is the free space wavelength of the wave energy
  • helix 51 is illustrated as being Wound of a conducting material of the type that forms a high resistance oxide coating upon the surfaces thereof exposed to air, such as aluminum.
  • oxide coating 52 forms upon helix 51 which provides a uniform insulating separation between adjacent turns.
  • Lossy casing 53 of the type already described is laid over helix 51. Since materials such as aluminum have little resilience, a helix 54 of spring steel may be wound over casing 53 to maintain the circularity of helix 51. An outer weather proof casing 55 may then form the outside shield.
  • Fig. 6 another embodiment of the invention is shown that is suitable for application where unusual mechanical strength is required of the transmission line, such as in an underground or underwater application.
  • the line comprises a solid core 61 of low loss dielectric material. Core 61 may be extruded from a semiflexible material such as polyethylene. Helix 62 is wound directly upon core 61. A high loss casing 63, in accordance with the invention is applied over helix 62.
  • Fig. 7 a novel method and apparatus for assembling a transmission line is shown in diagrammatic form.
  • the conductive helix 71 is wound upon a suitably held mandrel 72 of diameter equal to the required internal diameter of the helix. Over this is spirally wound a Cil 6 tape or ribbon 75 of the lossy, resistive material suspended in a binder of thermal setting plastic such as Minnesota Mining and Manufacturing Company type EC-880. Over this is Wound the supporting spring 73 or protective casing or both as a particular application may require.
  • this assembled combination is slipped or drawn from the free end 76 of mandrel 72, it is passed through an oven or near a heating element 74, which causes successive turns of ribbon 75 to melt, fuse or blend together to form a substantially unitary cylindrical casing.
  • a ribbon of lossy, resistive material may be coated on one or both sides by a thermal bonding adhesive before it is wound. Upon heating, the adhesive binds all of the assembled components together.
  • the conductive and supporting helical members in the above described embodiments have been illustrated as having substantially circular cross-sections certain advantages have been found to making these members of elongated materials of rectangular cross section.
  • the helix should be wound with the Wide dimension of the rectangular cross section extending parallel to the axis of the helix. This provides a maximum of longitudinal coverage along the helix with a minimum of the material being used.
  • means for producing the circular electric mode of said wave energy means for utilizing said circular electric Wave energy
  • transmission means connecting said utilizing means to said producing means comprising an elongated member of conductive material wound in a substantially helical form and a jacket of electrically dissipative material surrounding said conductive material, said helix having a diameter greater than one Wavelength of said Wave energy, said helix having adjacent turns thereof electrically insulated from each other to expose all longitudinal current components to said electrically dissipative material at least once every quarter wavelength of high frequency wave energy propagated along said transmission means and spaced substantially less than one quarter Wavelength to expose circumferential current components of said circular electric mode to said dissipative material to a substantially smaller degree than the exposure of said longitudinal current components.

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  • Waveguides (AREA)
US416316A 1954-03-15 1954-03-15 Electromagnetic wave transmission Expired - Lifetime US2848696A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US416316A US2848696A (en) 1954-03-15 1954-03-15 Electromagnetic wave transmission
FR1118560D FR1118560A (fr) 1954-03-15 1955-01-13 Dispositif de transmission d'ondes électromagnétiques
DEW15821A DE1021044B (de) 1954-03-15 1955-01-25 Hohlleiter zur UEbertragung hochfrequenter elektromagnetischer Wellen eines H -Typs
NL194602A NL99249C (OSRAM) 1954-03-15 1955-02-07
GB7235/55A GB764737A (en) 1954-03-15 1955-03-11 Improvements in or relating to electromagnetic wave transmission systems
BE536466D BE536466A (OSRAM) 1954-03-15 1955-03-14

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US416316A US2848696A (en) 1954-03-15 1954-03-15 Electromagnetic wave transmission

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US2848696A true US2848696A (en) 1958-08-19

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US416316A Expired - Lifetime US2848696A (en) 1954-03-15 1954-03-15 Electromagnetic wave transmission

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US (1) US2848696A (OSRAM)
BE (1) BE536466A (OSRAM)
DE (1) DE1021044B (OSRAM)
FR (1) FR1118560A (OSRAM)
GB (1) GB764737A (OSRAM)
NL (1) NL99249C (OSRAM)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2915715A (en) * 1956-07-20 1959-12-01 Bell Telephone Labor Inc Helical wave guides
US2950454A (en) * 1958-10-30 1960-08-23 Bell Telephone Labor Inc Helix wave guide
US2968775A (en) * 1957-12-20 1961-01-17 Bell Telephone Labor Inc Electromagnetic wave attenuator
US2978657A (en) * 1959-04-30 1961-04-04 Bell Telephone Labor Inc Microwave mode filter
US3008102A (en) * 1957-01-16 1961-11-07 Varian Associates Cavity resonator methods and apparatus
US3016503A (en) * 1959-12-29 1962-01-09 Bell Telephone Labor Inc Helix wave guide
US3020501A (en) * 1956-05-12 1962-02-06 Emi Ltd Waveguides
US3056710A (en) * 1958-12-12 1962-10-02 Bell Telephone Labor Inc Method for constructing a wave guide
US3066268A (en) * 1955-08-05 1962-11-27 Int Standard Electric Corp Electric waveguide construction
US3066269A (en) * 1957-05-17 1962-11-27 Barlow Harold Everar Monteagle Tubular waveguides
US3090019A (en) * 1959-02-24 1963-05-14 Andrew Corp Flexible waveguide
US3110001A (en) * 1957-08-23 1963-11-05 Bell Telephone Labor Inc Unwanted mode absorbing circular wave guide having circumferential gaps coupled, by intermediate dielectric, to external dissipative sheath
US3126517A (en) * 1964-03-24 Tapered waveguide transition sections
US3158824A (en) * 1957-03-27 1964-11-24 Siemens Ag Tubular wave guide for transmitting circular-electric waves
US3210695A (en) * 1960-12-05 1965-10-05 Gen Bronze Corp Waveguide assembled from four thin sheets and strengthened by external reinforcement, and its method of manufacture
US3257630A (en) * 1961-04-07 1966-06-21 Post Office Variable phase shifter, utilizing extensible helical waveguide, for circular te modes
US3573681A (en) * 1969-03-12 1971-04-06 Bell Telephone Labor Inc Helical waveguide formed from dielectric ribbon having symmetrically disposed conductive strips on opposite sides
US3605046A (en) * 1969-03-12 1971-09-14 Bell Telephone Labor Inc Deflection-free waveguide arrangement
US3678420A (en) * 1970-10-27 1972-07-18 Bell Telephone Labor Inc Spurious mode suppressing waveguide
US3748606A (en) * 1971-12-15 1973-07-24 Bell Telephone Labor Inc Waveguide structure utilizing compliant continuous support
US3750058A (en) * 1971-12-08 1973-07-31 Bell Telephone Labor Inc Waveguide structure utilizing compliant helical support
US3771077A (en) * 1970-09-24 1973-11-06 F Tischer Waveguide and circuit using the waveguide to interconnect the parts
US5013130A (en) * 1989-07-31 1991-05-07 At&T Bell Laboratories Method of making a carbon coated optical fiber
US5057781A (en) * 1989-07-31 1991-10-15 At&T Bell Laboratories Measuring and controlling the thickness of a conductive coating on an optical fiber
US20050184880A1 (en) * 2004-02-24 2005-08-25 Li Gao Method and system for well telemetry
WO2012128866A1 (en) 2011-03-22 2012-09-27 Giboney Kirk S Gap-mode waveguide
US20230008455A1 (en) * 2021-07-06 2023-01-12 Quaise, Inc. Multi-piece corrugated waveguide

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL121090C (OSRAM) * 1957-08-23
GB890799A (en) * 1957-08-23 1962-03-07 Western Electric Co Improvements in or relating to transmission media for electromagnetic wave energy in the circular electric mode
US2940057A (en) * 1957-11-01 1960-06-07 Bell Telephone Labor Inc Selective mode filters
NL257671A (OSRAM) 1960-01-14
US4401363A (en) 1979-10-15 1983-08-30 National Research Development Corporation Optical waveguide and method of propagating waves therein
FR2477766A1 (fr) * 1980-03-05 1981-09-11 Anvar Cellule d'absorption destinee a recevoir un gaz ou une vapeur rarefie, utilisable pour la stabilisation en frequence d'un oscillateur electrique et la spectrometrie

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR427599A (fr) * 1911-02-02 1911-08-08 Harle Et Cie Soc Conducteur pour le courant électrique
FR869734A (fr) * 1939-09-19 1942-02-13 Fides Gmbh Câble diélectrique à ondes ultra-courtes
US2416177A (en) * 1944-06-20 1947-02-18 Callenders Cable & Const Co Wave guide for high-frequency electric currents
US2626371A (en) * 1948-07-16 1953-01-20 Philco Corp Traveling wave tube attenuator
US2779006A (en) * 1949-12-02 1957-01-22 Bell Telephone Labor Inc Spurious mode suppressing wave guides

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE915099C (de) * 1945-04-19 1954-07-15 Siemens Ag Koaxiales Hochfrequenzkabel mit einem mit kleiner Steigung gewickelten Innenleiter
DE874475C (de) * 1949-09-04 1953-04-23 Siemens Ag Koaxiales Hochfrequenzkabel mit einem mit kleiner Steigung um einen Traeger gewickelten Innenleiter

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR427599A (fr) * 1911-02-02 1911-08-08 Harle Et Cie Soc Conducteur pour le courant électrique
FR869734A (fr) * 1939-09-19 1942-02-13 Fides Gmbh Câble diélectrique à ondes ultra-courtes
US2416177A (en) * 1944-06-20 1947-02-18 Callenders Cable & Const Co Wave guide for high-frequency electric currents
US2626371A (en) * 1948-07-16 1953-01-20 Philco Corp Traveling wave tube attenuator
US2779006A (en) * 1949-12-02 1957-01-22 Bell Telephone Labor Inc Spurious mode suppressing wave guides

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3126517A (en) * 1964-03-24 Tapered waveguide transition sections
US3066268A (en) * 1955-08-05 1962-11-27 Int Standard Electric Corp Electric waveguide construction
US3020501A (en) * 1956-05-12 1962-02-06 Emi Ltd Waveguides
US2915715A (en) * 1956-07-20 1959-12-01 Bell Telephone Labor Inc Helical wave guides
US3008102A (en) * 1957-01-16 1961-11-07 Varian Associates Cavity resonator methods and apparatus
US3158824A (en) * 1957-03-27 1964-11-24 Siemens Ag Tubular wave guide for transmitting circular-electric waves
US3066269A (en) * 1957-05-17 1962-11-27 Barlow Harold Everar Monteagle Tubular waveguides
US3110001A (en) * 1957-08-23 1963-11-05 Bell Telephone Labor Inc Unwanted mode absorbing circular wave guide having circumferential gaps coupled, by intermediate dielectric, to external dissipative sheath
US2968775A (en) * 1957-12-20 1961-01-17 Bell Telephone Labor Inc Electromagnetic wave attenuator
US2950454A (en) * 1958-10-30 1960-08-23 Bell Telephone Labor Inc Helix wave guide
US3056710A (en) * 1958-12-12 1962-10-02 Bell Telephone Labor Inc Method for constructing a wave guide
US3090019A (en) * 1959-02-24 1963-05-14 Andrew Corp Flexible waveguide
US2978657A (en) * 1959-04-30 1961-04-04 Bell Telephone Labor Inc Microwave mode filter
US3016503A (en) * 1959-12-29 1962-01-09 Bell Telephone Labor Inc Helix wave guide
US3210695A (en) * 1960-12-05 1965-10-05 Gen Bronze Corp Waveguide assembled from four thin sheets and strengthened by external reinforcement, and its method of manufacture
US3257630A (en) * 1961-04-07 1966-06-21 Post Office Variable phase shifter, utilizing extensible helical waveguide, for circular te modes
US3573681A (en) * 1969-03-12 1971-04-06 Bell Telephone Labor Inc Helical waveguide formed from dielectric ribbon having symmetrically disposed conductive strips on opposite sides
US3605046A (en) * 1969-03-12 1971-09-14 Bell Telephone Labor Inc Deflection-free waveguide arrangement
US3771077A (en) * 1970-09-24 1973-11-06 F Tischer Waveguide and circuit using the waveguide to interconnect the parts
US3678420A (en) * 1970-10-27 1972-07-18 Bell Telephone Labor Inc Spurious mode suppressing waveguide
US3750058A (en) * 1971-12-08 1973-07-31 Bell Telephone Labor Inc Waveguide structure utilizing compliant helical support
US3748606A (en) * 1971-12-15 1973-07-24 Bell Telephone Labor Inc Waveguide structure utilizing compliant continuous support
US5057781A (en) * 1989-07-31 1991-10-15 At&T Bell Laboratories Measuring and controlling the thickness of a conductive coating on an optical fiber
US5013130A (en) * 1989-07-31 1991-05-07 At&T Bell Laboratories Method of making a carbon coated optical fiber
US20050184880A1 (en) * 2004-02-24 2005-08-25 Li Gao Method and system for well telemetry
US7046164B2 (en) 2004-02-24 2006-05-16 Halliburton Energy Services, Inc. Method and system for well telemetry
WO2012128866A1 (en) 2011-03-22 2012-09-27 Giboney Kirk S Gap-mode waveguide
US20230008455A1 (en) * 2021-07-06 2023-01-12 Quaise, Inc. Multi-piece corrugated waveguide
US11613931B2 (en) * 2021-07-06 2023-03-28 Quaise, Inc. Multi-piece corrugated waveguide
US11959382B2 (en) 2021-07-06 2024-04-16 Quaise Energy, Inc. Multi-piece corrugated waveguide
US12270300B2 (en) 2021-07-06 2025-04-08 Quaise Energy, Inc. Multi-piece corrugated waveguide

Also Published As

Publication number Publication date
BE536466A (OSRAM) 1959-01-16
NL99249C (OSRAM) 1961-10-16
FR1118560A (fr) 1956-06-07
DE1021044B (de) 1957-12-19
GB764737A (en) 1957-01-02

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