US2624859A - Traveling wave amplifier tube - Google Patents

Traveling wave amplifier tube Download PDF

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Publication number
US2624859A
US2624859A US758848A US75884847A US2624859A US 2624859 A US2624859 A US 2624859A US 758848 A US758848 A US 758848A US 75884847 A US75884847 A US 75884847A US 2624859 A US2624859 A US 2624859A
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US
United States
Prior art keywords
wave
helix
travelling
mode
tube
Prior art date
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
Application number
US758848A
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English (en)
Inventor
Louis D Smullin
Gordon C Dewey
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.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE483594D priority Critical patent/BE483594A/xx
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Priority to US758848A priority patent/US2624859A/en
Priority to GB9305/48A priority patent/GB660793A/en
Priority to FR968664D priority patent/FR968664A/fr
Application granted granted Critical
Publication of US2624859A publication Critical patent/US2624859A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
    • H01J23/24—Slow-wave structures, e.g. delay systems
    • H01J23/30—Damping arrangements associated with slow-wave structures, e.g. for suppression of unwanted oscillations

Definitions

  • Our invention relates -tofamplers of the travelling wave type and has for its object the prevention of ringing and oscillatlngfof such ampliers.
  • Travelling wave tubes known generally to the art today, consist of a tightly Wound helix down which 'an 'electromagnetic wave can propagate.
  • the phase velocity of propagation of .the electromagnetic wave along the axis of the helix is small compared to the vvelocity of light and the mode of propagation of this wave i's-called the slowed-up mode.
  • An electron beam is arranged to direct astreamlof electrons'axially through the helix.
  • vWe accomplish these and other objects by placing lossy or absorbing material (that is, a material that will attenuate electromagnetic Waves that pass therethrough) adjacent the helix of the conventional travelling wave amplifier' tubein a region in which the electromagnetic Wave travelling in-a fastm'ode through said helix is'strongfand the wave travelling in thev slowedup -rnode is extremely weak or effectively Vnegligible.
  • lossy or absorbing material that is, a material that will attenuate electromagnetic Waves that pass therethrough
  • Fig. 1 is-a cross-sectional view of a travelling -Wave tubeshowing features of my invention
  • Fig. 2 is a graph'of the magnitudes of the intensities of *the electro-magnetic waves travelling in the slowed-up mode and in another Amode relative'to their maximum values through the helix as a'function of the distance from the center-of the-helix;
  • Figs. 3 and 4 are ycross-sectional views of Ya seriously travelling wave tube showing two other embodiments of our'invention.
  • the tube of our invention is generally illustrated'in'Figl. vAn ⁇ envelope l encloses an electron gun 2, Ifocusing electrodes '3 and 4, tightly woun'd helix '5, and collector electrode 6, arranged in the order named from end to end of ⁇ the tube.
  • the axis of the helix li is aligned with theelectron gun 2 whiohi's indirectlyheated by Yc oil"l.,"leads 8 fand 9 'of said coal being connected across abattery l0.
  • a lead Il from the electron gun is connected tothe negative side of a high tensionsource I2.
  • Leads I3 and I4 Afrorn focusing electrodes v3 and 4 are connected to low voltage points of said source l2.
  • a lead l5 from collectorelectrode Bis also connected to a low voltage point of 'the source. 'This is done so that the unconverted portion yof the kinetic energy of the beam does'no't necessarily appear as dissipated power at the collector electrode.
  • a lead I8 from the helix 5 is connected to the positive end of the high tension source l2.
  • the helix 5 is connected at either end to metal cylinders or collars 'I'I and I8, each arranged coaxially about the beam path and adapted to fit inside the glass envelope.
  • the helix 5 is connected to the collars H and I8 by means of straight conducting stubs l 9 and 20.
  • provided with apertures therethrough and closed at one end 22 is arranged with the envelope of the tube through the apertures such that the stub I9 which is connected to the helix at the end adjacent the electron gun projects into the guide 2l.
  • the guide 2l consttutes the input wave guide.
  • an apertured rectangular wave guide 23 with a closed end 24 is arranged with the stub 20 projecting therein.
  • the guide 23 constitutes the output wave guide.
  • a solenoid 25 is arranged coaxially about the helix 5 for focusing ⁇ the beam therethrough.
  • a lossy material 26 such as granulated carbon in a binder or a thin metallic illm or coating whose thickness is small compared to their skin depth, is arranged coaxially about the glass envelope between the envelope and the solenoid or coated in the glass envelope on the outside thereof see Fig. 3) or on the inside thereof (see Fig. 4)
  • the operation of the device is as follows: An ultra high frequency wave is fed through wave guide 2
  • the helix 5 propagates the -wave therealong from the end adjacentthe electron gun to--the end adjacent the collector electrode in a slowed-up mode.
  • the axial velocity of the wave is small compared to the velocity of light.
  • An electron beam is directed axially through the helix at a velocity slightly greater than the axial phase velocity.
  • the wave has an axial electric field component which slows up the electrons in the beam and thus the kinetic energy of the beam is transformed into electromagnetic energy and the wave taken off in the output guide is amplified.
  • the impedance matching between the output guide 23 and the helical guide via the stub 2i) is not perfect there will be reflection of the electromagnetic waves through the helix from the collector towards the electron gun.
  • the reflected waves constitute feedback and they cause the tube to oscillate.
  • the helix may be made lossy, that is, it may be made to attenuate the reflected wave.
  • experiment shows that oscillations occur with a lossy helix in which G L 1. This suggests that there exists a wave travelling in a faster mode along the axis of the helix. In fact the wave travels with approximately the velocity of light.
  • the fast mode suiers much less attenuation due to the lossy helix since there are fewer wave lengths of it than of the Wave of the slowed-up mode.
  • absolute values of the electric field intensities of waves travelling in the slow and the fast modes are a maximum at a radius r1 from the center of the helix, the helix itself having a radius r1.
  • the eld intensity of the slowed up wave falls off rapidly for values of radius greater than r1 and is practically negligible for a radius T2.
  • the electric eld intensity of the fast wave falls 01T much less rapidly for values of the radius greater than r1 and is of substantial intensity at the distance r2 from the center of the helix.
  • a lossy material of proper attenuation characteristic and of cylindrical shape of radius r2 will attenuate the wave of the unwanted fast mode and will have negligible eiTect upon that of the wanted slow mode.
  • a travelling wave amplifier comprising an electron gun and a collector electrode dening an electron beam path therebetween, an envelope about said gun and said collector electrode, a wave guide including a helix of wire located about said beam path for propagating an electromagnetic wave along said beam path in the direction from said gun to said collector electrode, said electromagnetic wave being propagated along said wave guide with an axial phase velocity slightly less than the velocity of the electrons in said beam and a length of electromagnetic field attenuation material disposed and extending therealong for substantially the entire length thereof, said attenuation material comprising a cylindrical form of lossy material located coaxially about said helix of wire, said helix being located inside said envelope and said attenuation material being located outside and about said envelope.
  • a travelling wave amplifier comprising an electron gun and a collector electrode dening an electron beam path therebetween, an envelope about said gun and said collector electrode, a wave guide including a helix of wire located about said beam path for propagating an electromagnetic wave along said beam path in the direction from said gun to said collector electrode, said electromagnetic wave being propagated along said wave guide with an axial phase velocity slightly less than the velocity of the electrons in said beam and a length of electromagnetic iield attenuation material disposed and extending therealong for substantially the entire length thereof, said attenuation material comprising a cylindrical form of lossy material located coaxially about said helix of wire, said helix being located inside said envelope and said attenuation material comprising a coating of lossy material on the outside of said envelope.

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  • Microwave Tubes (AREA)
US758848A 1947-07-03 1947-07-03 Traveling wave amplifier tube Expired - Lifetime US2624859A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE483594D BE483594A (fr) 1947-07-03
US758848A US2624859A (en) 1947-07-03 1947-07-03 Traveling wave amplifier tube
GB9305/48A GB660793A (en) 1947-07-03 1948-04-02 Method of preventing oscillations in travelling wave tubes
FR968664D FR968664A (fr) 1947-07-03 1948-07-01 Procédés pour empêcher des oscillations nuisibles dans des tubes à onde progressive

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US758848A US2624859A (en) 1947-07-03 1947-07-03 Traveling wave amplifier tube

Publications (1)

Publication Number Publication Date
US2624859A true US2624859A (en) 1953-01-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
US758848A Expired - Lifetime US2624859A (en) 1947-07-03 1947-07-03 Traveling wave amplifier tube

Country Status (4)

Country Link
US (1) US2624859A (fr)
BE (1) BE483594A (fr)
FR (1) FR968664A (fr)
GB (1) GB660793A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2850704A (en) * 1955-02-04 1958-09-02 Hughes Aircraft Co Waveguide coupling
US2892121A (en) * 1954-03-25 1959-06-23 Varian Associates Electron discharge device
US3411033A (en) * 1967-02-21 1968-11-12 Hughes Aircraft Co Electron beam focusing device employing a foil wound solenoid

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE973327C (de) * 1951-04-19 1960-01-21 Standard Elek K Lorenz Ag Wanderfeldwendelroehre mit selbsttragendem Roehrensystem
DE974255C (de) * 1954-08-05 1960-11-10 Standard Elek K Lorenz Ag Wanderfeldverstaerkerroehre mit mindestens zwei in Elektronenstrahlrichtung hintereinanderliegenden Wendeln
US3397339A (en) * 1965-04-30 1968-08-13 Varian Associates Band edge oscillation suppression techniques for high frequency electron discharge devices incorporating slow wave circuits

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1957538A (en) * 1931-06-13 1934-05-08 Bell Telephone Labor Inc Electrical network
US2233126A (en) * 1933-10-23 1941-02-25 Rca Corp Device for and method of controlling high frequency currents
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2367295A (en) * 1940-05-17 1945-01-16 Bell Telephone Labor Inc Electron discharge device
US2413608A (en) * 1945-03-12 1946-12-31 Hazeltine Research Inc Time-delay network

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1957538A (en) * 1931-06-13 1934-05-08 Bell Telephone Labor Inc Electrical network
US2233126A (en) * 1933-10-23 1941-02-25 Rca Corp Device for and method of controlling high frequency currents
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2367295A (en) * 1940-05-17 1945-01-16 Bell Telephone Labor Inc Electron discharge device
US2413608A (en) * 1945-03-12 1946-12-31 Hazeltine Research Inc Time-delay network

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892121A (en) * 1954-03-25 1959-06-23 Varian Associates Electron discharge device
US2850704A (en) * 1955-02-04 1958-09-02 Hughes Aircraft Co Waveguide coupling
US3411033A (en) * 1967-02-21 1968-11-12 Hughes Aircraft Co Electron beam focusing device employing a foil wound solenoid

Also Published As

Publication number Publication date
FR968664A (fr) 1950-12-01
GB660793A (en) 1951-11-14
BE483594A (fr)

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