EP0316092A1 - Magnetronanoden - Google Patents

Magnetronanoden Download PDF

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Publication number
EP0316092A1
EP0316092A1 EP88310043A EP88310043A EP0316092A1 EP 0316092 A1 EP0316092 A1 EP 0316092A1 EP 88310043 A EP88310043 A EP 88310043A EP 88310043 A EP88310043 A EP 88310043A EP 0316092 A1 EP0316092 A1 EP 0316092A1
Authority
EP
European Patent Office
Prior art keywords
anode
vanes
magnetron
temperature
main body
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Withdrawn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
EP88310043A
Other languages
English (en)
French (fr)
Inventor
Michael Barry Clive Brady
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
Application filed by EEV Ltd filed Critical EEV Ltd
Publication of EP0316092A1 publication Critical patent/EP0316092A1/de
Withdrawn legal-status Critical Current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
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H01J25/52—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode
    • H01J25/58—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode having a number of resonators; having a composite resonator, e.g. a helix
    • H01J25/587—Multi-cavity magnetrons
    • 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
    • H01J23/165—Manufacturing processes or apparatus therefore

Definitions

  • This invention relates to anodes for use in magnetrons.
  • FIG. 1 One common type of magnetron anode is shown in plan view in Figure 1 and comprises an outer cylinder 1 bearing a number of vanes 2, the whole structure usually being formed from copper.
  • the cavities between the vanes resonate electrically, and the resonant frequency determines the operating frequency of the magnetron.
  • the resonance frequency of the cavities varies with the temperature of the anode due to thermal expansion of the anode.
  • a magnetron may be expected to operate at any temperature in the range -50°C to + 100°C, so the change in the resonance frequency of the anode may be quite significant. As a result, the operating frequency of the magnetron will alter noticeably across its operating temperature range.
  • the whole anode can be constructed from a material having a low thermal expansivity.
  • such an anode will always exhibit some change in resonant frequency with temperature also, such materials are often unsuitable for use in an anode because of other properties required for anode material, such as high termal and electrical conducitivity, nonmagnetism and no outgassing when heated in a vaccum.
  • This invention provides an anode for use in a magnetron, the anode comprising a main body portion and a plurality of vanes,characterised by the body being formed from a first material and the vanes being formed from a second material, the first and second materials having different thermal expansivities.
  • the resonant frequency f of a magnetron anode is related to its capacitance C and inductance L by the equation:
  • the inductance of the anode is proportional to the area A between adjacent vanes.
  • the capacitance of the anode is inversely proportional to the separation T between the tips of adjacent vanes.
  • the first material has a greater thermal expansivity than the second material. This allows the resonant frequency of the anode to be made proportional, rather than inversely proportional, to temperature or preferably independent of temperature.
  • the main body of the anode from copper and the vanes from molybdenum because these materials have very good electrical and thermal conductivities and have widely differing thermal expansivities and are both non-magnetic.
  • Figure 2 shows an end view of a magnetron anode employing the invention.
  • a magnetron anode 3 is shown in solid lines in a first low temperature position and in dashed lines 3/ in a second higher temperature position.
  • the anode is formed from an outer copper main body 4,4′ and eight molybdenum vanes 5,5′.
  • the molybdenum vanes, 5,5′ are secured to the copper main body 4,4′ by plating the vanes 5,5′ with nickel and then copper and then brazing them to the main body, 4,4′.
  • vanes 5,5′ are formed of molybdenum and the main body 4,4. is formed of copper, they expand differentially and the relative rates of change of A and T with temperature can be selected to be the same by choosing an appropriate profile for the vanes 5.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Microwave Tubes (AREA)
EP88310043A 1987-11-12 1988-10-26 Magnetronanoden Withdrawn EP0316092A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8726539A GB2212323A (en) 1987-11-12 1987-11-12 Magnetron anodes
GB8726539 1987-11-12

Publications (1)

Publication Number Publication Date
EP0316092A1 true EP0316092A1 (de) 1989-05-17

Family

ID=10626858

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88310043A Withdrawn EP0316092A1 (de) 1987-11-12 1988-10-26 Magnetronanoden

Country Status (3)

Country Link
EP (1) EP0316092A1 (de)
JP (1) JPH01281640A (de)
GB (1) GB2212323A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0519803A1 (de) * 1991-06-21 1992-12-23 Thomson Tubes Electroniques Magnetrone mit Abgleichringen und Frequenzstabilisierung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2444419A (en) * 1942-12-24 1948-07-06 Gen Electric Magnetron
US2810094A (en) * 1955-10-11 1957-10-15 Palmer P Derby Method for frequency compensating a magnetron anode for temperature change
US2852720A (en) * 1953-08-12 1958-09-16 Litton Industries Inc Frequency stable magnetron

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL68027C (de) * 1942-10-01
FR963238A (de) * 1947-03-15 1950-07-01
US3289037A (en) * 1963-04-29 1966-11-29 Litton Industries Inc Temperature compensated magnetron anode structure having alternate segments of differing thermal expansion coefficient
GB1073121A (en) * 1965-03-23 1967-06-21 M O Valve Co Ltd Improvements in or relating magnetrons
GB8507721D0 (en) * 1985-03-25 1985-05-01 M O Valve Co Ltd Magnetrons

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2444419A (en) * 1942-12-24 1948-07-06 Gen Electric Magnetron
US2852720A (en) * 1953-08-12 1958-09-16 Litton Industries Inc Frequency stable magnetron
US2810094A (en) * 1955-10-11 1957-10-15 Palmer P Derby Method for frequency compensating a magnetron anode for temperature change

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0519803A1 (de) * 1991-06-21 1992-12-23 Thomson Tubes Electroniques Magnetrone mit Abgleichringen und Frequenzstabilisierung
FR2678107A1 (fr) * 1991-06-21 1992-12-24 Thomson Tubes Electroniques Magnetron strape a stabilisation de frequence.

Also Published As

Publication number Publication date
JPH01281640A (ja) 1989-11-13
GB2212323A (en) 1989-07-19
GB8726539D0 (en) 1987-12-16

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19891118