US2861212A - Travelling wave magnetron tube - Google Patents

Travelling wave magnetron tube Download PDF

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Publication number
US2861212A
US2861212A US298368A US29836852A US2861212A US 2861212 A US2861212 A US 2861212A US 298368 A US298368 A US 298368A US 29836852 A US29836852 A US 29836852A US 2861212 A US2861212 A US 2861212A
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United States
Prior art keywords
wave
tube
delay line
electrons
high frequency
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Expired - Lifetime
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US298368A
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English (en)
Inventor
Lerbs Alfred
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CIE GENERALE DE ELEGRAPHIE SAN
GENERALE DE ELEGRAPHIE SANS FIL Cie
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CIE GENERALE DE ELEGRAPHIE SAN
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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
    • H01J25/42—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and with a magnet system producing an H-field crossing the E-field
    • 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

Definitions

  • This invention relates to travelling wave magnetron tubes.
  • a well known form of amplifier or frequency multiplier for very short (decimetre or centimetre) waves is the so-called travelling wave tube.
  • a wave fed into a delay line forming part of the tube is amplified by interaction with an electron beam which is propagated in a direction parallel to said line and perpendicular to crossed electric and magnetic fields, the speed of the beam being substantially equal to the ratio of' these two fields and to the speed of phase propagation of the wave.
  • the present invention seeks to provide a travelling wave tube of improved efiiciency, and this object is achieved by dividing the delay line into two sections, the first of which is placed in the negative electrode of the interaction space.
  • Figure 1 is a diagrammatic section illustrating a known amplifier tube of the travelling wave type in question.
  • FIGS. 2a, 2b are diagrams explaining the functioning of this tube.
  • Figures 3a, 3b, 3c, 3d are similar diagrams for a tube the input of "which is coupled to a delay line forming the negative electrode.
  • FIG. 4 is a diagrammatic section of an amplifier or frequency multiplier tube in accordance with this invention.
  • Figure 5 illustrates an external excitation oscillator using a tube of the same type as Figure 4.
  • Figure 6 is a cross section of a tube according to any of Figures 1, 4 or 5 showing the pole pieces 11, 12 of the magnetic system for producing the magnetic field.
  • the electrons of an electronic beam 1 issueing from a cathode 2 enter the interaction space situated between a delay line 3 which is maintained at a positive potential, and a negative electrode 6.
  • the delay line has an input 4 and an output 5 for the high frequency wave.
  • the electrons are first focused in respect ofphase and then yield their continuous potential energy to the high frequency field of the travelling wave. In the course of this yield of energy, the electrons approach the line 3, while in the absence of the high frequency field they are collected by a collector 7.
  • a part of the line 3 carries an attenuator layer '8 in order to avoid self-oscillation.
  • the part 9 of the line functions principally as a phase focuser, and the part. 10
  • An electric field of value E transverse to the beam and situated in the plane of the figure is established between the electrodes 3 and 6, and a magnetic field of value B related to the electric field E and the speed v of the electrons by the relation is established perpendicularly to the plane of the figure.
  • Figure 2a In Figure 2a are shown the lines of force of the high frequency field which are displaced in space at the phase speed ofthe wave.
  • Figure 2b shows the equipotential lines of the resultant field.
  • the transverse component of the high frequency field is subtractive with respect to the D. C. field E at points such as A, C, E and that it is additive thereto at intermediate points such as B, D so that the resultant transverse field becomes alternately weaker and stronger than the D. C. field at the points A, B, C, D and E.
  • the speed of the beam in the D. C. field is equal to the ratio E /8, the electric force acting on the electrons is balanced by the Lorentz force due to the speed of the electrons and to the magnetic field.
  • the transverse high frequency component alternately subtracted from and added to the D. C. component, acting jointly with the magnetic field, imparts to the electrons a supplementary speed which is superimposed on the continuous speed and which is such that the complement of the electric force is balanced by the complement of the Lorentz force.
  • the electrons are thus retarded or accelerated depending on their position in relation to the travelling wave, as indicated by the arrows between Figures 2a and 2b.
  • the present invention which does not have the disadvantages of the previous proposals referred to, consists in dividing the interaction space into two parts, the energy exchange mechanism in the first part being the inverse of the mechanism explained with the aid of Figures 2a and 2b;
  • the present invention therefore divides the delay line into two sections, the first of which, placed in the negative electrode, is relatively short.
  • the effect obtained will then be that illustrated in Figures 3a and 3b, and not that illustrated in Figures 3a and 3d, that is to say the electrons will be strongly focused, with very favourable consequences for the electronic efficiency in the course of normal amplification in the interaction space of the second section.
  • the attenuation of the wave brought to the input of the first section it will be made up and even exceeded by the gain realised in the course of the amplification of the second section, so that at the output an improved efficiency will be obtained while losing nothing in respect of amplification as compared with the known tube illustrated in Figure 1.
  • Figure 4 illustrates diagrammatically a simple embodiment of the invention.
  • the references correspond to those in Figure 1, from which Figure 4 differs only by the fact that the first section 9 is placedin alignment with the negative electrode 6 and brought to the same potential as the latter. It is thus opposite the attenuated section Sconnected to the second positive section 10.
  • the electromagnetic wave enters at 4 and, as has been explained, causes strong focusing of the electrons of the beam 1.
  • the focused electrons penetrate into the interaction space 4 between 6 and 10, and at 10 excite a travelling wave which enters into interaction with the beam as in the known tube illustrated in Figure 1. That is to say the high frequency field of the wave excited in the line 10 continues to focus the electrons, which continually yield a part of their potential energy to'the field of the wave as they approach the line.
  • the main advantages of this invention are (1) The tube is made relatively short.
  • the cathode is preferably brought to a slightly more positive potential than the potential of the focusing line.
  • the tube illustrated in Figure 4 can also function as a frequency multiplier if the dimensions are made such that the wave excited in the section 10 is of a harmonic frequency in relation to the wave in the section 9, the
  • phase speeds in the two sections which are equal to the speed of the beam, corresponding on the one hand to the fundamental wave and on the other hand to the desired harmonic wave.
  • An arrangement in accordance with the invention may advantageously utilise a delay line propagating energy in the opposite direction to the beam, which, as is well known, is a property characterising for example symmetrical interdigital lines or so-called meander-wound (zig-zag) lines.
  • Such lines are likely to cause selfoscillations if used in known travelling wave tubes, but in arrangements according to this invention, such lines may be used in the focusing section 9 without the danger of self-oscillation and, without having to provide any artificial attenuation means.
  • a traveling wave tube of the type comprising a cathode, a delay line and a smooth electrode, parallel to said delay line and defining therewith an electron and wave interaction space, said cathode being positioned for propagating an electron beam in said space, said tube further comprising an additional delay line portion extending between said cathode and said electrode.
  • a traveling wave tube of the type comprising a cathode, a delay line and a smooth electrode, parallel to said delay line and defining therewith an electron and wave interaction space, said cathode being positioned for propagating an electron beam in said space, said tube furthercomprising an additional delay line portion in alignment with said electrode and extending between said cathode and said electrode.
  • a traveling wave tube of the type comprising a cathode, a delay line and a smooth electrode, parallel to said delay line and defining therewith an electron and wave interaction space, said cathode being positioned for propagating an electron beam in said space, said tube further comprising an additional delay line portion in alignment with said electrode and extending between said cathode and said electrode, said delay line comprising an attenuated part facing said additional delay line portion.
  • a traveling wave tube of the type comprising a cathode, a delay line and a smooth electrode, parallel to said delay line and defining therewith an electron and wave interaction space, said cathode being positioned for propagating an electron beam in said space, said tube further comprising an additional delay line portion in alignment With said electrode and an additional smooth electrode portion in alignment with said delay line, said additional delay line portion extending between said cathode and said electrode, and said additional smooth electrode portion facing said delay line portion over at least a portion thereof.

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  • Microwave Amplifiers (AREA)
US298368A 1951-07-30 1952-07-11 Travelling wave magnetron tube Expired - Lifetime US2861212A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR2861212X 1951-07-30

Publications (1)

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US2861212A true US2861212A (en) 1958-11-18

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US (1) US2861212A (de)
BE (1) BE512834A (de)
FR (1) FR1046766A (de)
GB (1) GB712565A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2992354A (en) * 1954-03-04 1961-07-11 Csf Travelling wave tubes
US3073991A (en) * 1958-09-29 1963-01-15 Raytheon Co Electron sorting devices
US3084275A (en) * 1959-09-28 1963-04-02 Raytheon Co Delay lines for traveling wave tubes
US3243735A (en) * 1960-04-01 1966-03-29 Siemen & Halske Ag Delay line for travelling wave tubes
DE1297765B (de) * 1960-12-10 1969-06-19 Raytheon Co Wanderfeldroehre mit gekreuzten statischen elektrischen und magnetischen Feldern

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE959298C (de) * 1954-08-10 1957-03-07 Siemens Ag Elektronenroehre fuer sehr hohe Frequenzen nach Art einer Wanderfeldroehre
US2970241A (en) * 1958-01-08 1961-01-31 Klein Gerald Backward wave tube amplifieroscillator
US4608520A (en) * 1983-07-29 1986-08-26 Varian Associates, Inc. Cathode driven crossed-field amplifier

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2414121A (en) * 1941-01-17 1947-01-14 Bell Telephone Labor Inc Electron device of the magnetron type
US2511407A (en) * 1947-01-09 1950-06-13 Csf Amplifying valve of the progressive wave type
US2531972A (en) * 1949-02-12 1950-11-28 Csf Ultra short wave transmitting tube
US2602148A (en) * 1946-10-22 1952-07-01 Bell Telephone Labor Inc High-frequency amplifier
US2620458A (en) * 1949-03-31 1952-12-02 Raytheon Mfg Co Microwave amplifier
US2622158A (en) * 1951-02-16 1952-12-16 Patelhold Patentverwertung Microwave amplifier
US2687777A (en) * 1948-07-20 1954-08-31 Csf Thermionic tube for ultrashort waves
US2694783A (en) * 1949-03-21 1954-11-16 Csf Electron gun for traveling-wave tubes with a transverse magnetic field

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2414121A (en) * 1941-01-17 1947-01-14 Bell Telephone Labor Inc Electron device of the magnetron type
US2602148A (en) * 1946-10-22 1952-07-01 Bell Telephone Labor Inc High-frequency amplifier
US2511407A (en) * 1947-01-09 1950-06-13 Csf Amplifying valve of the progressive wave type
US2687777A (en) * 1948-07-20 1954-08-31 Csf Thermionic tube for ultrashort waves
US2531972A (en) * 1949-02-12 1950-11-28 Csf Ultra short wave transmitting tube
US2694783A (en) * 1949-03-21 1954-11-16 Csf Electron gun for traveling-wave tubes with a transverse magnetic field
US2620458A (en) * 1949-03-31 1952-12-02 Raytheon Mfg Co Microwave amplifier
US2622158A (en) * 1951-02-16 1952-12-16 Patelhold Patentverwertung Microwave amplifier

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2992354A (en) * 1954-03-04 1961-07-11 Csf Travelling wave tubes
US3073991A (en) * 1958-09-29 1963-01-15 Raytheon Co Electron sorting devices
US3084275A (en) * 1959-09-28 1963-04-02 Raytheon Co Delay lines for traveling wave tubes
US3243735A (en) * 1960-04-01 1966-03-29 Siemen & Halske Ag Delay line for travelling wave tubes
DE1297765B (de) * 1960-12-10 1969-06-19 Raytheon Co Wanderfeldroehre mit gekreuzten statischen elektrischen und magnetischen Feldern

Also Published As

Publication number Publication date
BE512834A (de)
GB712565A (en) 1954-07-28
FR1046766A (fr) 1953-12-09

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