US3509412A - Multicavity klystron for microwave and uhf with interfering mode suppression slots in the ends of the drift tube - Google Patents

Multicavity klystron for microwave and uhf with interfering mode suppression slots in the ends of the drift tube Download PDF

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Publication number
US3509412A
US3509412A US692183A US3509412DA US3509412A US 3509412 A US3509412 A US 3509412A US 692183 A US692183 A US 692183A US 3509412D A US3509412D A US 3509412DA US 3509412 A US3509412 A US 3509412A
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United States
Prior art keywords
drift tube
slots
klystron
uhf
microwave
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Expired - Lifetime
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US692183A
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English (en)
Inventor
Enzio Demmel
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US Philips Corp
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US Philips Corp
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Application filed by US Philips Corp filed Critical US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • H01P7/06—Cavity resonators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • H01J25/10—Klystrons, i.e. tubes having two or more resonators, without reflection of the electron stream, and in which the stream is modulated mainly by velocity in the zone of the input resonator
    • H01J25/12—Klystrons, i.e. tubes having two or more resonators, without reflection of the electron stream, and in which the stream is modulated mainly by velocity in the zone of the input resonator with pencil-like electron stream in the axis of the resonators

Definitions

  • This invention relates to a multicavity klystron for the microwave and UHF-regions having a centrally-arranged multicavity through which an electron ray passes and which is interrupted in the chambers for acting on the electron ray, an airgap being present between its two ends terminating in each chamber.
  • Multicavity klystrons for the frequency ranges above identified are known in a great variety of forms. It is also known that these klystron devices can operate not only on a given frequency, the so-called fundamental mode, but under certain conditions also oscillate at several other frequencies, so that the desired operation is liable to be considerably disturbed. With such a multicavity klystron placed in a pulse-modulated amplifying device it was found that the output signal of the klystron was materially distorted and partly collapsed in a certain region of the ray voltage.
  • the distortion of the output signal in a given region of the ray voltage was found to be caused by the occurrence of a self-generated oscillation of, for example, 8000 mc./sec., whereas the klystron was operated at a frequency of approximately 3000 mc./sec.
  • the occurrence of this self-generated oscillation premises that at least two of the cavities of the tube design have the same mode of oscillation at neighbouring frequencies and that sufficient feedback also exists between the relevant cavities, which may be given, for example, by the H -mode in the drift tube connecting the cavities.
  • the present invention avoids these disadvantages and is based on recognition of the fact that selective influencing of the interfering modes is possible since, in contrast with the cavity modes usually employed in klystrons, the interfering modes exhibit an azimuthal dependence upon the magnitudes determining the field and the wall current.
  • the invention therefore suggests forming at least one slot of suitable length in at least one end of the drift tube in at least one cavity, which slot begins at the airgap and extends in the axial direction.
  • the interference modes are inductively loaded and shifted to lower frequencies to an extent United States Patent 0 dependent upon the dimensions of the slot formed, so that self-oscillation no longer occurs as a result of the frequency difference thus obtained between the modes taking part in the self-generating oscillation. Furthermore it appeared that the interference modes are not only shifted to lower frequencies but also their amplitude is attenuated. Due to the steps according to the invention, the mode used in the klystron is influenced netiher in frequency nor in coupling properties to any appreciable extent.
  • At least one end of the hollow guide may be provided with a plurality of slots of equal or different lengths having positions which are mutually shifted by
  • one end of a portion of the hollow guide may be provided with slots which are shifted by 90 relative to slots formed in the other end of the same portion of the hollow guide.
  • both ends of the hollow guide located in a cavity may be provided with slots situated in 90 shifted positions. In all these devices the width of the slot may be small relative to the transverse dimensions of the hollow guide.
  • FIGURE 1 shows a multi-cavity klystron
  • FIGURES 2a and 2b are plan views on the tube ends of the drift tube.
  • FIGURE 1 shows a centrally-arranged drift tube 1 through which an electron ray passes.
  • the drift tube 1 is interrupted in cavities 2 in order that the electron ray may be influenced by an electric high-frequency field active in a gap 3.
  • the two ends 4 and 5 of the drift tube lie in the cavity 2 and form therewith an assembly which is capable of resonating.
  • the drift tube 1 forms the connection to the next cavity 2, which connection is indicated by a broken line 6 since, for example, another cavity 2 may be arranged at this area.
  • the invention is not confined to the rotation-symmetrical embodiment of the drift tube and cavities which is shown and can use a different cross-section.
  • the incoupling and outcoupling devices in the cavities 2 are omitted for the sake of clarity.
  • Such a system of double cavities may be caused to resonate upon occurrence of an interference mode at a given value of the ray voltage.
  • An interference oscillation may be prevented by forming axial slots 7 in the ends 4 and 5 of the hollow guide 1, which constitute an inductive load for the interference mode and may be regarded as short circuited branch guides for the interference mode.
  • the slots 7 in the upper cavity may be formed in position shifted 90. Also, the slot 7 in the guide portion 8 in the upper cavity may have a 90 shifted position relative to the slot 9 in the lower chamber. In this example it has been assumed that the guide portion 8 also extends into the lower system and another cavity is not interposed.
  • FIGURE 2 is a plan view on the lower ends 4 and 5 of the drift tube 1, each having two slots 7 situated at right angles to each other, thus suppressing the two interference modes in one cavity.
  • the drift tube 1 need not extend into the cavity 2 at its two ends 4 and 5. It is also possible that, for example, the
  • the width of the slots must be small relative to the transverse dimensions of the drift tube 1, that is to say in the rotation-symmetrical design of the drift tube 1 the width of the slots must be small relative to the diameter of the drift tube 1, in order that the fundamental mode or the desired mode is influenced to the least possible extent.
  • a klystron for the microwave and UHF regions comprising a plurality of resonant cavities, a drift tube connecting said resonant cavities and terminating in each cavity resonator and defining an interaction gap therein, at least one interference mode suppressing slot extending from the inner to the outer surface and of suitable length in at least one end of the drift tube in at least one cavity resonator, said slot beginning at the airgap and extending in the axial direction.
  • a klystron as claimed in claim 1 wherein at least one end of the drift tube is provided with a plurality of slots having positions which are mutually shifted by 3.

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  • Microwave Tubes (AREA)
US692183A 1966-12-24 1967-12-20 Multicavity klystron for microwave and uhf with interfering mode suppression slots in the ends of the drift tube Expired - Lifetime US3509412A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEP0041095 1966-12-24

Publications (1)

Publication Number Publication Date
US3509412A true US3509412A (en) 1970-04-28

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ID=7377567

Family Applications (1)

Application Number Title Priority Date Filing Date
US692183A Expired - Lifetime US3509412A (en) 1966-12-24 1967-12-20 Multicavity klystron for microwave and uhf with interfering mode suppression slots in the ends of the drift tube

Country Status (7)

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US (1) US3509412A (de)
BE (1) BE708492A (de)
DE (1) DE1541027C2 (de)
ES (1) ES348536A1 (de)
FR (1) FR1549049A (de)
GB (1) GB1213465A (de)
NL (1) NL6717628A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902098A (en) * 1973-06-22 1975-08-26 Nippon Electric Co Linear beam microwave tube having means coupled to the beam upstream of input coupler and/or downstream of output coupler for varying amplitude and/or phase of r.f. component in the beam
US5038077A (en) * 1989-01-31 1991-08-06 The United States Of American As Represented By The Secretary Of The Navy Gyroklystron device having multi-slot bunching cavities

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939037A (en) * 1956-01-30 1960-05-31 Varian Associates Apparatus for suppression of multipactor
US3287673A (en) * 1965-03-15 1966-11-22 Fred G Hammersand Attenuator for suppressing high-order cavity resonances having a transverse electric component
US3376524A (en) * 1964-07-13 1968-04-02 Sperry Rand Corp Double-mode broadband resonant cavity

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL285748A (de) * 1961-12-01 1900-01-01

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939037A (en) * 1956-01-30 1960-05-31 Varian Associates Apparatus for suppression of multipactor
US3376524A (en) * 1964-07-13 1968-04-02 Sperry Rand Corp Double-mode broadband resonant cavity
US3287673A (en) * 1965-03-15 1966-11-22 Fred G Hammersand Attenuator for suppressing high-order cavity resonances having a transverse electric component

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3902098A (en) * 1973-06-22 1975-08-26 Nippon Electric Co Linear beam microwave tube having means coupled to the beam upstream of input coupler and/or downstream of output coupler for varying amplitude and/or phase of r.f. component in the beam
US5038077A (en) * 1989-01-31 1991-08-06 The United States Of American As Represented By The Secretary Of The Navy Gyroklystron device having multi-slot bunching cavities

Also Published As

Publication number Publication date
NL6717628A (de) 1968-06-25
GB1213465A (en) 1970-11-25
DE1541027B1 (de) 1970-01-15
DE1541027C2 (de) 1970-08-20
ES348536A1 (es) 1969-03-16
FR1549049A (de) 1968-12-06
BE708492A (de) 1968-06-24

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