US3573681A - Helical waveguide formed from dielectric ribbon having symmetrically disposed conductive strips on opposite sides - Google Patents

Helical waveguide formed from dielectric ribbon having symmetrically disposed conductive strips on opposite sides Download PDF

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Publication number
US3573681A
US3573681A US806662A US3573681DA US3573681A US 3573681 A US3573681 A US 3573681A US 806662 A US806662 A US 806662A US 3573681D A US3573681D A US 3573681DA US 3573681 A US3573681 A US 3573681A
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United States
Prior art keywords
strips
ribbon
helix
conductive strips
waveguide
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Expired - Lifetime
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US806662A
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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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    • 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

  • a helix waveguide structure is adapted to printed circuit techniques.
  • the wire helix of the prior art is replaced by pairs of helices printed on opposite sides of a low loss dielectric member.
  • the structure is advantageously fabricated by printing conductive strips on both sides of a dielectric ribbon and winding the ribbon into helix form.
  • the propagation of microwave energy in the form of TE waves in circular waveguides is ideally suited for the long distance transmission of wide band signals since the attenuation characteristic of this transmission mode, unlike that of all other modes, decreases with increasing frequency.
  • one difficulty with this method of transmission is that the TE mode is not the dominant mode supported in a circular waveguide, and consequently energy may be lost to other modes also capable .of transmission therein.
  • the propagation of TE waves therethrough is undisturbed, but slight imperfections in the guide and especially curvature of the waveguide 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 TE and other transmission modes, mainly the TM TE and TE modes.
  • the prior art has provided a large number of devices for negotiating bends or turns in the guides.
  • the phase velocity of the TM mode (which is normally equal to that of the TE mode) is changed relative to that of the TE mode, to increase the relative differences in their propagation constants and to reduce the effective coupling therebetween.
  • the waveguide such as is described in US. Pat. No. 2,848,696, issued to S. E. Miller on Aug. 19, I958.
  • the waveguide comprises an elongated member of insulated conducting material, such as enameled wire, would in a circular helix.
  • the helix is typically covered with an electrically lossy material and surrounded by an outer shielding jacket, such as a steel tube, to protect it from external mechanical and electrical influences.
  • the helix When the inside diameter of the helix is greater than 1.22 times the free space wavelength of the lowest frequency wave to be propagated and the spacing between the centers of ad-- jacent turns of the helix is less than 0.25 times the wavelength of the highest frequency to be propagated, the helix will propagate frequencies within this bandwidth in the circular electric TE mode.
  • the undesired TM modes produce predominantly longitudinal wall currents and are seriously affected by the insulated separation between adjacent turns of the helix.
  • the circular electric mode produces circumferential currents which are not appreciably interfered with by the helical structure.
  • the longitudinal currents of the undesired TM modes are forced to flow through the lossy material resulting in increased attenuation for these modes.
  • the field of the circular electric mode does not penetrate through the space between adjacent conductors into the lossy material (provided the diameter of the conducting wire is comparable to or larger than the spacing between adjacent turns) because the two adjacent conductors act as a waveguide beyond cutoff.
  • the phase velocity of the TM mode in such a waveguide is significantly different from that of the TE, mode, and the power transferred between the two modes in a bend is substantially reduced.
  • the conductive strips must be thicker than can be conveniently made by conventional printed circuit techniques.
  • the conductive layers should have a thickness comparable to or greater than the spacing between adjacent strips in order to prevent loss to the TE. mode.
  • the minimum allowable spacing is limited by the requirement that the capacitance between adjacent strips be kept low. Consequently, in waveguides for the millimetric range, the conductor thickness should be on the order of a few mils while conventional printed circuit techniques are typically limited to conductors on the order of one mil or less.
  • a new waveguide structure has been devised to permit the use of printed circuit techniques in the fabrication of helical waveguides.
  • the wire helix of the prior art is replaced by a double helix which can be advantageously provided by printing pluralities of pairs of thin conductive strips on opposite sides of a low loss dielectric ribbon.
  • FIG. 1 is a perspective view of a printed circuit tape useful in fabricating a helical waveguide in accordance with the invention.
  • FIG. 2 is a partially cross-sectional view of a typical helical waveguide in accordance with the invention.
  • FIG. 1 is a perspective view of a printed circuit tape useful in fabricating a helical waveguide in accordance with the invention. It shows a plurality of thin strips 10 of conductive material such as copper disposed on opposite parallel sides of a flexible, low loss dielectric ribbon such as mylar tape. The conductive strips are substantially coextensive across the dielectric. As in the prior art the center-to-center spacing, D, between adjacent conductive strips 10 is less than one-quarter wavelength. For millimetric waves, this spacing is typically on the order of 4 mils. The spacing, S, between the edges of adjacent strips is determined by the desired capacitance and is typically on the order of a mil. The thickness, T, of the strips can be chosen for convenience of fabrication.
  • the strips are fabricated by printed circuited techniques and the thickness is on the order of 0.1 mil.
  • the thickness T of the dielectric ribbon 11 is comparable to or larger than the spacing S but less than one-half wavelength of the highest frequency wave to be propagated. For millimetric waveguide this can be on the order of 3 mils.
  • the length L of the dielectric tape is determined by the maximum allowable pitch angle in the helical waveguide. Typically it can be at least enough to hold two or three conducting strips.
  • this printed circuit tape can be fabrication of the helix.
  • the helix is formed by windconveniently fabricated by using printed circuit techniques to produce the conductive strips.
  • the tape can then be wound into a helical waveguide using substantially the same processes as used in the prior art with the tape substituted for a single strand of wire. Since the tape is stronger than a single thin strand of wire, breakage is less likely; and since the tape carries more than one conducting strip, the number of turns required to produce a given length of helix is proportionately reduced. In addition, since much thinner conductors are used, there is a saving of this material.
  • FIG. 2 is a partially cross-sectional view of a typical helical waveguide structure made in accordance with the invention.
  • the waveguide comprises a helix 20 of printed circuit tape as described in FIG. 1, an electrically lossy layer 21, i.e. typically a material having a resistivity on the order of one ohm-centimeter, surrounding and bonded to helix 20 and an outer shielding jacket 22 to protect the helix from external mechanical and electricalinfluences.
  • the conductive strips form a helical waveguide.
  • little or no TE mode energy propagates through the spaces between adjacent conductive strips.
  • the adjacent inner diameter strips and outer diameter strips behave as a waveguide surrounding the space between them. Thus, so long as the thickness T is comparable to or greater than the spacing S, the TE mode energy will see the space between adjacent strips as a waveguide beyond cutoff.
  • a transmission medium for guiding wave energy in the circular electric mode of wave propagation within a given band of frequencies comprising:
  • an elongated dielectric ribbon member having a plurality of conductive strips symmetrically located on opposite surfaces thereof;
  • said strips are conductively insulated from each other and have a center-to-center spacing of less than onequarter wavelength of the highest frequency of said wave energy;
  • the thickness of said ribbon is comparable to or greater than the spacing between the edges of adjacent strips, but less than one-half wavelength of said highest frequency wave energy

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US806662A 1969-03-12 1969-03-12 Helical waveguide formed from dielectric ribbon having symmetrically disposed conductive strips on opposite sides Expired - Lifetime US3573681A (en)

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US80666269A 1969-03-12 1969-03-12

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US3573681A true US3573681A (en) 1971-04-06

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Country Status (7)

Country Link
US (1) US3573681A (fr)
JP (1) JPS4821238B1 (fr)
BE (1) BE747064A (fr)
DE (1) DE2011554A1 (fr)
FR (1) FR2034853B1 (fr)
GB (1) GB1271611A (fr)
SE (1) SE354153B (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3771076A (en) * 1971-02-03 1973-11-06 British Insulated Callenders Combined electromagnetic waveguide and mode filter
US3771078A (en) * 1971-02-02 1973-11-06 British Insulated Callenders Mode filter for an electromagnetic waveguide
US4419671A (en) * 1981-10-28 1983-12-06 Bell Telephone Laboratories, Incorporated Small dual frequency band hybrid mode feed
US5364136A (en) * 1991-11-12 1994-11-15 Alcatel Italia S.P.A. Flanges and bodies for microwave waveguides components
GB2550414A (en) * 2016-05-20 2017-11-22 Creo Medical Ltd Antenna structure
US11135006B2 (en) 2016-05-17 2021-10-05 Creo Medical Limited Electrosurgical cutting tool
US11613931B2 (en) * 2021-07-06 2023-03-28 Quaise, Inc. Multi-piece corrugated waveguide

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5113044U (fr) * 1974-07-16 1976-01-30
JPS5115740U (fr) * 1974-07-24 1976-02-04
JPS52121723U (fr) * 1976-03-12 1977-09-16
DE3906587A1 (de) * 1989-03-02 1990-09-06 Galvano T Electroforming Plati Hohlleiter aus einem elektrisch und thermisch gut leitenden metall

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2704829A (en) * 1951-10-01 1955-03-22 Rca Corp Delay line
DE950133C (de) * 1954-08-28 1956-10-04 Siemens Ag Elektrische Wellenfuehrungsanordnung
US2774046A (en) * 1952-05-08 1956-12-11 Itt Microwave transmission line
US2848696A (en) * 1954-03-15 1958-08-19 Bell Telephone Labor Inc Electromagnetic wave transmission
US2905858A (en) * 1953-06-30 1959-09-22 Bell Telephone Labor Inc Impedance matching by means of coupled helices
US2915718A (en) * 1955-08-05 1959-12-01 Itt Microwave transmission lines
US2950454A (en) * 1958-10-30 1960-08-23 Bell Telephone Labor Inc Helix wave guide
US3047822A (en) * 1957-12-23 1962-07-31 Thompson Ramo Wooldridge Inc Wave communicating device
US3106768A (en) * 1958-12-19 1963-10-15 Int Standard Electric Corp Waveguides
US3407366A (en) * 1964-10-06 1968-10-22 Vikoa Inc Antenna coupling apparatus for multiple receivers
US3411116A (en) * 1964-07-30 1968-11-12 Comp Generale Electricite Parasitic mode filter

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB934779A (en) * 1959-02-16 1963-08-21 Ass Elect Ind Improvements relating to radio wave polarisation rotators

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2704829A (en) * 1951-10-01 1955-03-22 Rca Corp Delay line
US2774046A (en) * 1952-05-08 1956-12-11 Itt Microwave transmission line
US2905858A (en) * 1953-06-30 1959-09-22 Bell Telephone Labor Inc Impedance matching by means of coupled helices
US2848696A (en) * 1954-03-15 1958-08-19 Bell Telephone Labor Inc Electromagnetic wave transmission
DE950133C (de) * 1954-08-28 1956-10-04 Siemens Ag Elektrische Wellenfuehrungsanordnung
US2915718A (en) * 1955-08-05 1959-12-01 Itt Microwave transmission lines
US3047822A (en) * 1957-12-23 1962-07-31 Thompson Ramo Wooldridge Inc Wave communicating device
US2950454A (en) * 1958-10-30 1960-08-23 Bell Telephone Labor Inc Helix wave guide
US3106768A (en) * 1958-12-19 1963-10-15 Int Standard Electric Corp Waveguides
US3411116A (en) * 1964-07-30 1968-11-12 Comp Generale Electricite Parasitic mode filter
US3407366A (en) * 1964-10-06 1968-10-22 Vikoa Inc Antenna coupling apparatus for multiple receivers

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3771078A (en) * 1971-02-02 1973-11-06 British Insulated Callenders Mode filter for an electromagnetic waveguide
US3771076A (en) * 1971-02-03 1973-11-06 British Insulated Callenders Combined electromagnetic waveguide and mode filter
US4419671A (en) * 1981-10-28 1983-12-06 Bell Telephone Laboratories, Incorporated Small dual frequency band hybrid mode feed
US5364136A (en) * 1991-11-12 1994-11-15 Alcatel Italia S.P.A. Flanges and bodies for microwave waveguides components
US11135006B2 (en) 2016-05-17 2021-10-05 Creo Medical Limited Electrosurgical cutting tool
GB2550414A (en) * 2016-05-20 2017-11-22 Creo Medical Ltd Antenna structure
US20190081403A1 (en) * 2016-05-20 2019-03-14 Creo Medical Limited Antenna structure
US11799206B2 (en) * 2016-05-20 2023-10-24 Creo Medical Limited Helical antenna structure
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

Also Published As

Publication number Publication date
JPS4821238B1 (fr) 1973-06-27
FR2034853A1 (fr) 1970-12-18
DE2011554A1 (de) 1970-10-01
FR2034853B1 (fr) 1974-05-24
BE747064A (fr) 1970-08-17
GB1271611A (en) 1972-04-19
SE354153B (fr) 1973-02-26

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