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US3315118A - High power travelling wave tube having a negative circuiarly polarized electric field component - Google Patents

High power travelling wave tube having a negative circuiarly polarized electric field component Download PDF

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Publication number
US3315118A
US3315118A US189474A US18947462A US3315118A US 3315118 A US3315118 A US 3315118A US 189474 A US189474 A US 189474A US 18947462 A US18947462 A US 18947462A US 3315118 A US3315118 A US 3315118A
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United States
Prior art keywords
electron beam
delay line
wave
velocity
travelling wave
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
US189474A
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English (en)
Inventor
Muller Rudolf
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.)
Siemens and Halske AG
Siemens Corp
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Siemens Corp
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Filing date
Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H01J25/38—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field the forward travelling wave being utilised
    • 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
    • H01J23/26—Helical slow-wave structures; Adjustment therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/49—Tubes using the parametric principle, e.g. for parametric amplification
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/78—Tubes with electron stream modulated by deflection in a resonator

Definitions

  • the invention disclosed herein is concerned with a high power travelling wave tube for producing and amplifying highest frequencies, comprising a delay line along which is propagated an electromagnetic wave which enters into reciprocal action with an electron beam guided in a longitudinal homogeneous magnetic field.
  • the average electron velocity is as to magnitude and direction approximated to the phase velocity of an electromagnetic wave propagated along the delay line.
  • a longitudinal magnetic field usually serves for guiding the electron beam. However, this magnetic field is not of direct importance for the high frequency mechanism of travelling wave tubes.
  • the operation respectively with regard to amplification and excitation of the electromagnetic wave along the line is based upon the reciprocal action with the so-called slow space charge wave in the electron beam.
  • the advantage of the travelling wave tube resides in its broad band characteristic.
  • the eiiiciency is however relatively low. The reason may be found in the velocity modulation of the electron beam effected by the reciprocal action between the electromagnetic wave and the space charge wave. It is due to this velocity modulation that the kinetic energy of the electron beam can be converted into high frequency only to a small percentage and that the kinetic energy remaining in the beam cannot be fully recovered. However, efiiciency is especially in connection with high capacity tubes of paramount importance.
  • the invention makes use of knowledge obtained with respect to waves in an electron beam, which is in a longitudinal homogeneous magnetic field affected by transverse electrical field components of an electromagnetic wave propagated along a delay line.
  • the longitudinal magnetic field is, in the presence oftransverse waves, of considerable importance for the high frequency behavior of the electron beam. It must be considered in this connection that fast and slow cyclotron waves form in the electron beam, owing to the deflecting action of the electrical transverse field with respect to the electron beam in the magnetic longitudinal field, whereby energy is supplied to the electron beam for the modulation of the fast wave, while energy is withdrawn from the electron beam for the modulation of the slow wave.
  • the cyclotron wave is described by a rotation and simultaneous translation of the electrons of the electron beam, resulting in the field diagram, for the cyclotron wave, in a spiral line along which the electrons are propagated.
  • the phase velocity of the cyclotron wave is respectively faster or slower than the average uniform velocity of the electrons, depending upon whether energy is supplied to or withdrawn from the electron beam incident to the modulation of such wave.
  • Two waves of a further wave type are formed in the electron beam in addition to the two cyclotron waves.
  • the phase velocity of the two synchronous waves is always equal to the electron wave velocity, the designation of these waves as synchronous being traceable to this fact.
  • the momentary image represents a spiral line just as in the case of the momentary image of the cyclotron wave.
  • the spiral line does not describe a rotation but only a translation.
  • a model of such a wave would depict, for example, a garden hose which is circularly moved in parallel to the axis of the water stream.
  • the two synchronous waves distinguish merely by their relative sense of rotation with respect to the cyclotron motion of the electrons.
  • the wave with positive circular polarization in the magnetic field in beam direction clockwise rotation
  • the wave with negative polarization counterclockwise rotation
  • the same kinetic energy is thereby respectively supplied to or withdrawn from all electrons. Accordingly, upon modulating the electron beam solely with the negative circularly polarized synchronous wave, the beam will be slowed as a whole.
  • the invention proposes to achieve a high power tube, wherein the reciprocal action between the signal wave and the electron beam does not cause a velocity modulation of the beam, with utilization of the above described known appearance of the synchronous waves, in connection with a travelling wave tube of the initially defined type, by causing the delay line to carry a negative cir cularly polarized wave with a transverse electrical field component, the phase velocity of such wave being equal to the velocity of the electrons.
  • the beam as a whole is slowed up, owing to the reciprocal action between the negative circularly polarized wave on the delay line and the electron beam, and it is, accordingly, possible to match the phase velocity of the line wave to the velocity of the electrons, thus obtaining a high degree of electronic efficiency.
  • the kinetic energy remaining in the beam can be nearly com pletely recovered by the slowing up actionl
  • FIG. 1 shows a linearly polarized electron beam which is modulated transversely, that is, cross-wise to its propagation direction;
  • FIG. 2 is a beam velocity-time or velocity-location diagram resulting in the beam operation according to FIG. 1;
  • FIG. 3 represents in diagrammatic manner an arrangement for withdrawing energy from the electron beam
  • FIG. 4 is a velocity-time diagram illustrating the withdrawal of energy from the electron beam effected by the arrangement according to FIG. 3;
  • FIG. 5 illustrates part of a four-conductor helix operating as a delay line carrying a circularly polarized wave
  • FIG. 6 shows a sectional view of the delay line of FIG. 5
  • FIG. 7 represents an efliciency diagram of a travelling wave tube according to the invention.
  • FIG. 8 is a velocity-time diagram of a velocity modu lated electron beam.
  • numeral 1 indicates the linearly polarized electron beam which is modulated in a transverse field.
  • the electrons themselves as in. the case of a synchronous wave, shall not have any transverse velocity.
  • Numerals 2 and 3 indicate electrical parts, representing a short portion of a delay line. Accordingly, a coupling gap may be visualized as being formed between the parts 2 and 3.
  • the region 5 of the electron beam moving in the direction ofthe arrow 4, is near the coupling gap, there will appear at the load resistor R a voltage with the indicated polarity.
  • the electron beam is accordingly slowed up in the region 5.
  • the electron velocity remains unaltered in the region 6, since such region is equally spaced from the parts 2 and 3.
  • the electron beam is again slowed up at the region 7, the polarity at the coupling gap being opposite to that shown when the region 7 nears the gap.
  • the electron beam according to FIG. 1 shall be polarized circularly with a counterclockwise sense of rotation. Moreover, this circularly polarized beam shall permeate an arrangement adapted to also withdraw therefrom energy in a direction extending perpendicularly to the plane of the drawing FIG. 1.
  • FIG. 3 shows a corresponding arrangement in sectional view, comprising electrically conductive parts 2, 3, 9 and 10 between which extends the spirally or helically formed beam 1.
  • the withdrawal of energy from the electron beam is illustrated in the velocity-time diagram presented in FIG. 4.
  • the crosshatched area 11, corresponding to the area 8 in FIG. 2, represents the energy given off to the parts 2 and 3.
  • Energy corresponding to the crosshatched area 12 is also given 011 to the parts 9 and 10.
  • a superposition of the areas 11 and 12 results in a criss-cross hatched rectangular area 13, that is, the beam is slowed up as a whole.
  • a four-conductor helix is adapted to operate as a delay line carrying a circularly polarized wave, FIG. 5 showing a part of such helix, comprising four conductors 14, 15, 16 and 17.
  • This delay line shall be energized so that the electric field is formed in a plane perpendicular to the longitudinal helix axis, always between oppositely positioned conductors 14, 15 or 16, 17, respectively.
  • FIG. 6 shows the delay line of FIG. 5 in sectional view.
  • Such a field distribution is obtained by feeding the signal wave to the pair of conductors 16 and 17 with a delay of a phase angle of 1r/ 2 as compared with feeding it to the pair of conductors 14 and 15.
  • the input coupling line is for this purpose suitably branched and the electrical length of the two branches of the input coupling line are dimensioned so as to result in the desired phase difference.
  • IG. 7 is an efiiciency diagram of a travelling Wave tube according to the invention.
  • the level 18 represents the kinetic beam power prior to entering into the delay line.
  • the kinetic beam power of the electron beam is within the delay line converted into high frequency energy, so that the power falls from the level 18 to the level 19.
  • the kinetc energy remaining in the beam between the delay line and the beam collector, at the level 19, can be recovered by the slowing up of the beam. Only a small part of the energy corresponding to the level 20 is lost as heat. The energy remaining in the beam could not be recovered to such extent in a previously known travelling wave tube, owing to the velocity modulation of the electron beam.
  • FIG. 8 shows the velocity time diagram of a velocity-modulated electron beam
  • a travelling wave tube for producing and amplifying highest frequencies, comprising (a) a delay line,
  • (d) means defining a longitudinal homogeneous magnetic field about said electron beam
  • a travelling wave tube includes a four-conductor helix, said helix being dimensioned and energized by said coupling means so that the electrical field is formed in a plane perpendicular to the helix axis, always between two oppositely disposed conductors of the helix.
  • a travelling wave tube wherein the signal wave is applied to one pair of oppositely positioned conductors with a phase difference of 1r/2 as compared with the application thereof to the second pair of oppositely disposed conductors.

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  • Particle Accelerators (AREA)
  • Microwave Tubes (AREA)
  • Microwave Amplifiers (AREA)
US189474A 1961-04-27 1962-04-23 High power travelling wave tube having a negative circuiarly polarized electric field component Expired - Lifetime US3315118A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES73696A DE1298198B (de) 1961-04-27 1961-04-27 Laufzeitroehre zur Verstaerkung hoechstfrequenter Signale, insbesondere fuer hohe Leistungen

Publications (1)

Publication Number Publication Date
US3315118A true US3315118A (en) 1967-04-18

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US189474A Expired - Lifetime US3315118A (en) 1961-04-27 1962-04-23 High power travelling wave tube having a negative circuiarly polarized electric field component

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US (1) US3315118A (de)
DE (1) DE1298198B (de)
GB (1) GB947552A (de)
NL (1) NL277346A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3428848A (en) * 1966-09-08 1969-02-18 Us Army Synchronous wave linear accelerator wherein the slow wave circuit couples only to the positive synchronous wave
US3760219A (en) * 1972-04-25 1973-09-18 Us Army Traveling wave device providing prebunched transverse-wave beam
US4855644A (en) * 1986-01-14 1989-08-08 Nec Corporation Crossed double helix slow-wave circuit for use in linear-beam microwave tube

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2830211A (en) * 1957-07-10 1958-04-08 Herman F Kaiser Microtron extraction tube
US2859375A (en) * 1955-08-04 1958-11-04 Hughes Aircraft Co Multifilar helix coupling

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2859375A (en) * 1955-08-04 1958-11-04 Hughes Aircraft Co Multifilar helix coupling
US2830211A (en) * 1957-07-10 1958-04-08 Herman F Kaiser Microtron extraction tube

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3428848A (en) * 1966-09-08 1969-02-18 Us Army Synchronous wave linear accelerator wherein the slow wave circuit couples only to the positive synchronous wave
US3760219A (en) * 1972-04-25 1973-09-18 Us Army Traveling wave device providing prebunched transverse-wave beam
US4855644A (en) * 1986-01-14 1989-08-08 Nec Corporation Crossed double helix slow-wave circuit for use in linear-beam microwave tube

Also Published As

Publication number Publication date
GB947552A (en) 1964-01-22
DE1298198B (de) 1969-06-26
NL277346A (de)

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