EP0534762A1 - Dielektrischer Stützstab für eine Wanderfeldröhre - Google Patents

Dielektrischer Stützstab für eine Wanderfeldröhre Download PDF

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Publication number
EP0534762A1
EP0534762A1 EP92308726A EP92308726A EP0534762A1 EP 0534762 A1 EP0534762 A1 EP 0534762A1 EP 92308726 A EP92308726 A EP 92308726A EP 92308726 A EP92308726 A EP 92308726A EP 0534762 A1 EP0534762 A1 EP 0534762A1
Authority
EP
European Patent Office
Prior art keywords
support rod
dielectric support
traveling
dielectric
wave 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.)
Withdrawn
Application number
EP92308726A
Other languages
English (en)
French (fr)
Inventor
Takayoshi Konishi
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.)
NEC Corp
Original Assignee
NEC 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
Application filed by NEC Corp filed Critical NEC Corp
Publication of EP0534762A1 publication Critical patent/EP0534762A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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

Definitions

  • the present invention relates to a dielectric support rod of a traveling-wave tube and, more particularly, to an anti-charge structure of the dielectric support rod.
  • a traveling-wave tube has a RF circuit for causing a RF component and an electron beam to interact with each other so as to amplify the RF component.
  • a RF circuit is supported in a vacuum sealing metal pipe generally by three dielectric support rods.
  • Figs. 1A and 1B show the structure of a RF circuit used in a conventional helix type traveling-wave tube.
  • a RF circuit 2 is supported in a vacuum sealing metal pipe 3 by dielectric support rods 1. More specifically, the RF circuit 2 is generally supported by the three dielectric support rods 1 spaced apart from each other at an equal angular interval of 120 ° so that the RF circuit 2 is supported in the metal pipe 3.
  • Figs. 2A and 2B show a conventional dielectric support rod.
  • the conventional dielectric support rod material is alumina (Al2O3) or beryllia (BeO).
  • BeO beryllia
  • boron nitride (BN) having a low dielectric constant has been used. Boron nitride, however, may be charged by an electron beam passing through the RF circuit to cause a change in potential, thereby forming an unstable electron beam track. In the worst case,the RF circuit may be damaged.
  • a thin carbon coating is formed on the surface of a boron nitride dielectric support rod 1 to cause charges to flow to the RF circuit or the vacuum sealing metal pipe through the coating layer according to a conventional technique.
  • This carbon coating causes an increase in RF loss to decrease the output or gain of the traveling-wave tube, resulting in inconvenience.
  • a dielectric support rod for a traveling-wave tube which supports an RF circuit of said traveling-wave tube, and has a coating thereon, characterized in that the coating on said rod comprises a dielectric having a secondary electron emission ratio of not less than 1 when primary electrons of eE (eV) are incident thereon, where E (V) is the voltage between a cathode and said RF circuit of said traveling-wave tube, and e (Coul) is the charge on an electron.
  • the dielectric to be coated on the surface is preferably alumina or beryllia.
  • the dielectric support rod Since the secondary electron emission ratio is 1 or more, the dielectric support rod is not negatively charged. Even if the dielectric support rod is positively charged, the potential of the dielectric support rod is increased to re-attract secondary electrons to the dielectric support rod, resulting in a small amount of positive charge. This positive charge does not disturb the track of the electron beam passing through the RF circuit.
  • charging is also suppressed by means of the outer coating layer even when electron beam bombardment occurs. Also, the peripheral potential is not much changed to prevent disturbance of the electron beam track.
  • the Joule loss is eliminated to prevent a decrease in gain and output of the traveling-wave tube.
  • FIG. 3A and 3B show the first embodiment of the present invention.
  • a thin alumina coating 11 having a thickness of about 5nm is formed on a boron nitride dielectric support rod 10.
  • Fig. 4 shows the secondary electron emission ratios of boron nitride and alumina.
  • a voltage E (V) between a cathode and a RF circuit of a traveling-wave tube is 10 kV.
  • V a voltage between a cathode and a RF circuit of a traveling-wave tube
  • electrons emitted from the cathode and accelerated pass through the RF circuit with a kinetic energy of 10 keV, and some electrons are incident on the dielectric support rod.
  • the dielectric support rod consists only of boron nitride
  • the secondary electron emission ratio of the dielectric support rod is less than 1, as is apparent from Fig. 4.
  • the dielectric support rod accumulates electrons and is negatively charged to decrease the peripheral potential. Therefore, the track of the electron beam passing through the RF circuit becomes unstable.
  • the dielectric support rod has a structure obtained by forming an aluminum coating on boron nitride, as shown in Figs. 3A and 3B, the secondary electron emission ratio is 1 or more even if electrons having a kinetic energy of 10 keV are incident, as is apparent from Fig. 4.
  • the dielectric support rod is not negatively charged.
  • the dielectric support rod may be positively charged, the potential of the positively charged dielectric support rod is increased to re-attract the secondary electrons.
  • the positive charge amount is small enough not to disturb the track of the electron beam passing through the RF circuit.
  • the dielectric support rod having the structure obtained by coating alumina on boron nitride charging is also suppressed by electron beam bombardment, and the peripheral potential is not much changed, thereby preventing the disturbance of the electron beam.
  • alumina is a dielectric, a Joule loss caused by a carbon coating can be prevented, and a decrease in gain and output of the traveling-wave tube can be prevented.
  • the second embodiment of the present invention exemplifies a beryllia coating formed on a boron nitride dielectric support rod in place of an alumina coating.
  • a beryllia coating formed on a boron nitride dielectric support rod in place of an alumina coating.
  • charging is expected to be prevented, and the disturbance of the electron beam track is also expected to be prevented, as can be apparent from Fig. 4.
  • beryllia has a larger heat conductivity and a smaller dielectric constant than those of alumina, the heat dissipation effect and efficiency of the traveling-wave tube better than those in the first embodiment can be expected.
  • alumina and beryllia dielectric coatings are formed in accordance with CVD (chemical vapour deposition) or ion plating.

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  • Microwave Tubes (AREA)
EP92308726A 1991-09-27 1992-09-24 Dielektrischer Stützstab für eine Wanderfeldröhre Withdrawn EP0534762A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP24866691A JPH0589788A (ja) 1991-09-27 1991-09-27 進行波管用誘電体支柱
JP248666/91 1991-09-27

Publications (1)

Publication Number Publication Date
EP0534762A1 true EP0534762A1 (de) 1993-03-31

Family

ID=17181536

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92308726A Withdrawn EP0534762A1 (de) 1991-09-27 1992-09-24 Dielektrischer Stützstab für eine Wanderfeldröhre

Country Status (2)

Country Link
EP (1) EP0534762A1 (de)
JP (1) JPH0589788A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5495144A (en) * 1993-02-03 1996-02-27 Nec Corporation Helical slow-wave circuit assembly with reduced RF losses
FR2883409A1 (fr) * 2005-03-18 2006-09-22 Thales Sa Procede de fabrication d'un top avec effet de charge reduit

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08111182A (ja) 1994-08-17 1996-04-30 Toshiba Corp 進行波管の遅波回路構体及びその製造方法
JP2006134751A (ja) * 2004-11-08 2006-05-25 Nec Microwave Inc 電子管
JP5310062B2 (ja) * 2009-02-13 2013-10-09 トヨタ自動車株式会社 プラズマ点火装置
CN114538933B (zh) * 2020-11-24 2022-11-22 娄底市安地亚斯电子陶瓷有限公司 一种行波管夹持杆的制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH326748A (de) * 1953-12-10 1957-12-31 Siemens Ag Wellenleiteranordnung für Wanderfeldröhren
US3466494A (en) * 1968-05-01 1969-09-09 Siemens Ag Traveling wave tube with delay line supports having a lossy layer and an insulation layer
DE3235753A1 (de) * 1982-09-27 1984-03-29 Siemens AG, 1000 Berlin und 8000 München Wanderfeldroehre mit einer wendelartigen verzoegerungsleitung
FR2646732A1 (fr) * 1989-05-04 1990-11-09 Raytheon Co Amplificateur a haute frequence possedant une structure a ondes lentes
EP0402549A1 (de) * 1984-12-18 1990-12-19 Thomson-Csf Lauffeldröhre mit wendelförmiger Verzögerungsleitung, welche mittels dielektrischer Halterungsstäbe aus Bornitrid an der Vakuumhülle befestigt ist

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH326748A (de) * 1953-12-10 1957-12-31 Siemens Ag Wellenleiteranordnung für Wanderfeldröhren
US3466494A (en) * 1968-05-01 1969-09-09 Siemens Ag Traveling wave tube with delay line supports having a lossy layer and an insulation layer
DE3235753A1 (de) * 1982-09-27 1984-03-29 Siemens AG, 1000 Berlin und 8000 München Wanderfeldroehre mit einer wendelartigen verzoegerungsleitung
EP0402549A1 (de) * 1984-12-18 1990-12-19 Thomson-Csf Lauffeldröhre mit wendelförmiger Verzögerungsleitung, welche mittels dielektrischer Halterungsstäbe aus Bornitrid an der Vakuumhülle befestigt ist
FR2646732A1 (fr) * 1989-05-04 1990-11-09 Raytheon Co Amplificateur a haute frequence possedant une structure a ondes lentes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5495144A (en) * 1993-02-03 1996-02-27 Nec Corporation Helical slow-wave circuit assembly with reduced RF losses
FR2883409A1 (fr) * 2005-03-18 2006-09-22 Thales Sa Procede de fabrication d'un top avec effet de charge reduit

Also Published As

Publication number Publication date
JPH0589788A (ja) 1993-04-09

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