EP0753877A2 - Linear electron beam tubes - Google Patents

Linear electron beam tubes Download PDF

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Publication number
EP0753877A2
EP0753877A2 EP96304943A EP96304943A EP0753877A2 EP 0753877 A2 EP0753877 A2 EP 0753877A2 EP 96304943 A EP96304943 A EP 96304943A EP 96304943 A EP96304943 A EP 96304943A EP 0753877 A2 EP0753877 A2 EP 0753877A2
Authority
EP
European Patent Office
Prior art keywords
grid
cavity
tube
capacitor
lead
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.)
Ceased
Application number
EP96304943A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0753877A3 (enrdf_load_stackoverflow
Inventor
Alan Hugh Pickering
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.)
Teledyne UK Ltd
Original Assignee
EEV Ltd
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 claimed from GBGB9514172.7A external-priority patent/GB9514172D0/en
Application filed by EEV Ltd filed Critical EEV Ltd
Publication of EP0753877A2 publication Critical patent/EP0753877A2/en
Publication of EP0753877A3 publication Critical patent/EP0753877A3/xx
Ceased legal-status Critical Current

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Classifications

    • 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
    • H01J25/04—Tubes having one or more resonators, without reflection of the electron stream, and in which the modulation produced in the modulator zone is mainly density modulation, e.g. Heaff tube
    • 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
    • H01J23/14—Leading-in arrangements; Seals therefor
    • H01J23/15—Means for preventing wave energy leakage structurally associated with tube leading-in arrangements, e.g. filters, chokes, attenuating devices

Definitions

  • This invention relates to linear electron beam tubes and more particularly to inductive output tubes (IOT's).
  • IOT's inductive output tubes
  • An IOT is an arrangement in which a high frequency input signal is applied via a resonant input cavity to a region between the cathode and grid of an electron gun. This produces modulation of the electron beam generated by the electron gun. The resulting density modulated beam is directed to interact with an output resonant cavity from which an amplified high frequency output signal is extracted.
  • the present invention seeks to provide an improved linear electron beam tube and in particular an improved IOT but it may also be applicable to other tubes in which an input cavity surrounds an electron gun.
  • a linear electron beam tube comprising an electron gun assembly including a cathode, grid and anode and in which, in use, a high frequency input signal to be amplified is applied to the grid/cathode region via an input resonant cavity arranged about the electron gun and wherein an electrical lead for applying voltage to the lead includes a filter for reducing leakage of rf signal via the lead.
  • the application of high frequency signals to the input cavity which are used to modulate the electron beam may also result in leakage of signal down the grid lead and this may interfere with the drive of the IOT.
  • This interference may be sufficiently severe as to prevent proper operation of the tube at certain frequencies over its bandwidth.
  • By including a high frequency filter in the grid lead such interference may be damped sufficiently that it no longer causes significant problems in the operation of the IOT.
  • the filter includes an inductor and a capacitor and in one advantageous embodiment of the invention, the inductor is connected to the grid mount at one end and to the capacitor at the other end.
  • the capacitor is of cylindrical configuration having a centre conductor via which a voltage is applied to the grid and a surrounding cylindrical member spaced therefrom. An air gap or some other dielectric material is present between the centre and outer parts. Other capacitor configurations may be used.
  • At least one of the capacitor and inductor is approximately one quarter wavelength long at a selected frequency.
  • the frequency selected is that which tends to cause interference if leakage along the grid lead occurs.
  • the cylindrical configuration of the preferred capacitor included in the filter is particularly compact and can be fabricated to high tolerances by accurately selecting spacers to define the gap between the inner and outer cylinders.
  • the input resonant cavity is of an annular configuration having inner and outer annular walls about a volume and the grid lead is arranged within the volume surrounded by the inner wall of the cavity.
  • the grid lead is extensive through an aperture in a wall of the inner part of the cavity and extends across the cavity to the grid or grid mount.
  • an IOT includes an electron gun assembly 1 having a cathode 2, a grid 3 and an anode 4, the electron gun 1 being surrounded by an annular input high frequency resonant cavity 5.
  • the input cavity 5 includes an outer part 6 and an inner part 7 which are separated by RF chokes 8 and 9 to prevent leakage of high frequency energy from the cavity.
  • a lead 10 to the grid 3 for applying a voltage thereto includes a cylindrical capacitor 11 and an inductor 12 each of which is one quarter of wavelength long at a selected frequency which is chosen so as to reduce high frequency signal loss down the grid lead.
  • the capacitor 11 is shown in greater detail in Figure 2 and includes a central conductor 13 having an aperture therein 14 into which the next section of the grid lead is connected to join to the inductor 12.
  • the other end of the inner conductor 13 includes an aperture 15 at which an external connector 16 is fixed for connection to the appropriate supply.
  • a hollow stainless steal cylinder 17 surrounds the central conductor 13 being spaced therefrom by alumina spacers 18 and 19 at each end to define an air gap 20 between them.
  • the outer cylinder 17 is connected to a plate 21 which is fixed to a transverse plate 22 of the IOT defining part of the inner portion 7 of the cavity 5. The capacitor is thus fixed securely to the tube in the region 23 within the annular cavity 5, the grid lead extending through the cavity 5 to the grid 3.

Landscapes

  • Microwave Tubes (AREA)
EP96304943A 1995-07-12 1996-07-04 Linear electron beam tubes Ceased EP0753877A2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9514172 1995-07-12
GBGB9514172.7A GB9514172D0 (en) 1995-07-12 1995-07-12 Linear electron beam tubes
GBGB9515232.8A GB9515232D0 (en) 1995-07-12 1995-07-25 Linear electron beam tubes
GB9515232 1995-07-25

Publications (2)

Publication Number Publication Date
EP0753877A2 true EP0753877A2 (en) 1997-01-15
EP0753877A3 EP0753877A3 (enrdf_load_stackoverflow) 1997-01-29

Family

ID=26307374

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96304943A Ceased EP0753877A2 (en) 1995-07-12 1996-07-04 Linear electron beam tubes

Country Status (4)

Country Link
EP (1) EP0753877A2 (enrdf_load_stackoverflow)
CN (1) CN1146621A (enrdf_load_stackoverflow)
CA (1) CA2181100A1 (enrdf_load_stackoverflow)
GB (1) GB2303245A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1024517A1 (en) * 1999-01-26 2000-08-02 Marconi Applied Technologies Limited Electron beam tubes
EP1020880A3 (en) * 1999-01-13 2004-12-01 E2V Technologies (UK) Limited Capacitor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104124125A (zh) * 2014-07-22 2014-10-29 中国科学院电子学研究所 具有双间隙输入腔的感应输出管

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2277194B (en) * 1993-04-13 1996-05-22 Eev Ltd Electron beam tubes
US5572092A (en) * 1993-06-01 1996-11-05 Communications And Power Industries, Inc. High frequency vacuum tube with closely spaced cathode and non-emissive grid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1020880A3 (en) * 1999-01-13 2004-12-01 E2V Technologies (UK) Limited Capacitor
EP1024517A1 (en) * 1999-01-26 2000-08-02 Marconi Applied Technologies Limited Electron beam tubes

Also Published As

Publication number Publication date
CA2181100A1 (en) 1997-01-13
GB9614050D0 (en) 1996-09-04
CN1146621A (zh) 1997-04-02
EP0753877A3 (enrdf_load_stackoverflow) 1997-01-29
GB2303245A (en) 1997-02-12

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