US3729644A - Helix traveling-wave tube - Google Patents

Helix traveling-wave tube Download PDF

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Publication number
US3729644A
US3729644A US00204218A US3729644DA US3729644A US 3729644 A US3729644 A US 3729644A US 00204218 A US00204218 A US 00204218A US 3729644D A US3729644D A US 3729644DA US 3729644 A US3729644 A US 3729644A
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United States
Prior art keywords
conductor
travelling
wave tube
helix
pitch
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Expired - Lifetime
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US00204218A
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English (en)
Inventor
T Okazaki
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.)
NEC Corp
Original Assignee
Nippon Electric Co Ltd
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/36—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy
    • H01J23/40—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy to or from the interaction circuit
    • H01J23/48—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy to or from the interaction circuit for linking interaction circuit with coaxial lines; Devices of the coupled helices type
    • H01J23/50—Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy to or from the interaction circuit for linking interaction circuit with coaxial lines; Devices of the coupled helices type the interaction circuit being a helix or derived from a helix

Definitions

  • a helix travelling-wave tube comprises coupling devices for matching the impedance discontinuity between the helix and the input or output elements.
  • the coupling device is provided with a conductor tape or rod near one end of the helix across at least one pitch of the helix.
  • HELIX TRAVELING-WAVE TUBE This invention relates to travelling-wave tubes using the helix as the slow wave circuit to interact with the electron beam, and particularly, the coupling structures at input and output terminals.
  • the coupling structure comprises, around each of the input and the output ends of the helix, a ringshaped electrode of the length of one-quarter wavelength at the center frequency and of an inner diameter closely fitting the helix.
  • a travelling-wave tube including a helical slow wave structure and means coupled to said structure adjacent one end thereof for transmitting a high-frequency electric signal between said structure and the external circuit, wherein the improvement comprises a conductor attached to the outer periphery of said structure substantially parallel to the axis of said structure adjacent said one end, said conductor bridging at least one pitch (i.e., one revolution) of said helical structure.
  • FIG. 1 shows an axial sectional view of one embodiment of this invention
  • FIG. 2 is an enlarged perspective view illustrating the coupling portion at which the helix is connected to the center conductor ofa coaxial cable;
  • FIG. 3 is a graph illustrating the matching characteristic of the embodiment of FIG. 2.
  • FIG. 4 shows a perspective view of the coupling structure employed in another embodiment of this invention.
  • FIGS. 1 and 2 there is shown a travelling-wave tube of 6 GI-Iz band wherein one end of the helix 1 is directly connected with the center conductor 3 of coaxial cable 2 for connecting the tube to an external circuit (not shown for purposes of simplicity).
  • the helix 1 is supported in a vacuum envelope 4 of non-magnetic metal on the center axis of the vacuum envelope 4 by conventional supporting means (not shown) of an insulating material, i.e., ceramic or quartz.
  • the helix 1 may be made ofa molybdenum wire having a diameter of 0.2 mm and provided with a mean diameter of 2 mm and a pitch P of 0.56 mm, the pitch P being increased at the end portion.
  • the pitches P and P shown in FIG. 1 may be 1.3 mm and 0.9 mm, respectively.
  • An elongated platinum tape 5 having a rectangular cross section of 0.5 mm X 0.1 mm is attached to the helix 1 by welding and is aligned so as to be substantially parallel with the center axis 9.
  • the tape 5 is mounted across the enlarged two pitches at the outer periphery of the helix 1.
  • FIG. 3 there is shown the matching characteristic of frequency f(GI-Iz) versus voltage standing wave ratio (V. S. W. R.) in which curve A is for the embodiment thus described, and curve B is for the case in which this invention is not applied thereto. As is apparent from the curves A and B, this invention remarkably improves the matching characteristic over wide frequency band.
  • conductor rod 5a is mounted at the end portion of the tape helix 1a.
  • the conductor rod 5a has about one pitch length, bridging the second turn and the third turn of the helix la at the end portion.
  • the helix may be provided with an extended pitch portion to which the conductor rod 5a is mounted.
  • the length of the helix bridged by the conductor, such as platinum tape 5 should be about one-quarter wavelength long along the helix at the center frequency. It is possible to achieve the best results by experimentally determining the length and the cross-sectional diameters of the conductor and the circumferential and the axial positions of the conductor relative to the helix. Furthermore, the helix as shown in FIGS. 1 and 2 may be preferably provided with the pitch tapered portions to obtain better matching characteristics.
  • a travelling-wave tube including a helical slow wave structure comprising a helical wire having a plurality of turns and means coupled to said structure adjacent one end thereof for transmitting a high-frequency electric signal between said structure and the external circuit, wherein the improvement comprises a conductor attached to the outer periphery of said structure substantially parallel to the longitudinal axis of said structure and adjacent said one end, said conductor bridging at least two adjacent turns of said wire, said adjacent turns constituting one pitch of said structure.
  • said signal transmitting means is a coaxial cable having a center conductor and a concentric outer conductor; the center conductor of said cable being directly connected to said one end of said structure.

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  • Microwave Tubes (AREA)
US00204218A 1970-12-04 1971-12-02 Helix traveling-wave tube Expired - Lifetime US3729644A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45107266A JPS5123146B1 (enrdf_load_stackoverflow) 1970-12-04 1970-12-04

Publications (1)

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US3729644A true US3729644A (en) 1973-04-24

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US00204218A Expired - Lifetime US3729644A (en) 1970-12-04 1971-12-02 Helix traveling-wave tube

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US (1) US3729644A (enrdf_load_stackoverflow)
JP (1) JPS5123146B1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104599924A (zh) * 2014-12-24 2015-05-06 中国电子科技集团公司第十二研究所 一种多级互作用系统螺旋线行波管

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2708727A (en) * 1952-06-12 1955-05-17 Bell Telephone Labor Inc Helix coupling arrangements
US2761915A (en) * 1952-02-08 1956-09-04 Bell Telephone Labor Inc Helix couplers
US2849651A (en) * 1952-08-23 1958-08-26 Bell Telephone Labor Inc Traveling wave tubes
US2890370A (en) * 1953-03-26 1959-06-09 Int Standard Electric Corp Travelling wave tubes
GB860451A (en) * 1959-07-17 1961-02-08 Mullard Ltd Travelling-wave tubes
US3114857A (en) * 1959-07-17 1963-12-17 Philips Corp Travelling-wave tube with connectors for the end turns of the helix

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761915A (en) * 1952-02-08 1956-09-04 Bell Telephone Labor Inc Helix couplers
US2708727A (en) * 1952-06-12 1955-05-17 Bell Telephone Labor Inc Helix coupling arrangements
US2849651A (en) * 1952-08-23 1958-08-26 Bell Telephone Labor Inc Traveling wave tubes
US2890370A (en) * 1953-03-26 1959-06-09 Int Standard Electric Corp Travelling wave tubes
GB860451A (en) * 1959-07-17 1961-02-08 Mullard Ltd Travelling-wave tubes
US3114857A (en) * 1959-07-17 1963-12-17 Philips Corp Travelling-wave tube with connectors for the end turns of the helix

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104599924A (zh) * 2014-12-24 2015-05-06 中国电子科技集团公司第十二研究所 一种多级互作用系统螺旋线行波管

Also Published As

Publication number Publication date
JPS5123146B1 (enrdf_load_stackoverflow) 1976-07-14

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