US2931943A - Magnetron with variable resonance frequency - Google Patents

Magnetron with variable resonance frequency Download PDF

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Publication number
US2931943A
US2931943A US531389A US53138955A US2931943A US 2931943 A US2931943 A US 2931943A US 531389 A US531389 A US 531389A US 53138955 A US53138955 A US 53138955A US 2931943 A US2931943 A US 2931943A
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US
United States
Prior art keywords
anode
cavities
magnetron
parts
groove
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.)
Expired - Lifetime
Application number
US531389A
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English (en)
Inventor
Backmark Nils Erik
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.)
JAKOBSBERGS ELEKTROTEKNISKA FA
JAKOBSBERGS ELEKTROTEKNISKA FABRIKER AB
Original Assignee
JAKOBSBERGS ELEKTROTEKNISKA FA
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/30—Angle modulation by means of transit-time tube
    • H03C3/32—Angle modulation by means of transit-time tube the tube being a magnetron
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K11/00—Resistance welding; Severing by resistance heating
    • B23K11/30—Features relating to electrodes
    • B23K11/3009—Pressure electrodes
    • 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
    • H01J23/18—Resonators
    • H01J23/20—Cavity resonators; Adjustment or tuning thereof
    • H01J23/213—Simultaneous tuning of more than one resonator, e.g. resonant cavities of a magnetron
    • 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

Definitions

  • At least one of the end surfaces of the anode in its longitudinal direction is provided with at least one groove protruding into the material of the anode from said end surface, the
  • electrically conductive parts or bodies are arranged such as to co-operate with the recesses formed by the aperture between the cavities in the anode in such a manner that the size of the apertures between the cavities, i.e. the metal filling in the apertures between the cavities, is varied when varying the position of said electricallyconductive parts in relation to the anode.
  • the groove forming a recess in the anode material at one ,end surface thereof is arranged concentrically with the anode, the conducting parts co-operating with the recess between adjacent cavities of the anode preferably being arranged on a common support, said support being movable in relation to the anode.
  • the support for the conducting parts co-operating with said recesses may be either rotatable in which case electrically conductingparts having different dimensions at different locations along the periphery i.e. seen in the rotational direction. of the support are arranged on said rotatable support, the parts having such a shape that, in a certain position of the support inrelation to the ano'de, substantially the same amount of metal filling is obtained in all the apertures between the cavities of the anode. or else the support may be displaceable-in the longitudinal or axial direction of the magnetron body.
  • the parts are thus displaceable in a circumferential direction in the groove of the anode body and the dimensions of them are such that the apertures in the anode between the cavities, seen in a radial section through the anode through the walls of the cavities, are varied as the metal parts are moved when rotating the support.
  • Said parts may thus be made in the form of parts insulated from each other and in a number corresponding to the number of cavities or a multiple of it.
  • the conducting parts may also be arranged on a conducting cylindrical shell, which, together with the parts, is arranged in the groove. This shell may then be secured to an insulating support in order to avoid eddy currents when moving the support.
  • the conducting parts arranged movably in v the groove or recesses are, in order to obtain the highest possible frequency variation, designed with such a shape that, at least in some position of the parts in relation to the anode body, they fill out the recesses formed by the groove in the anode walls entirely, seen in 'a radial section through the conducting parts of the anode.
  • the support for the metal parts protruding into the groove is preferably secured to a shaft arranged concentrically with the mode.
  • a magnetron means for periodically varying of the resonance frequency of such a magnetron means may be provided for applying to the support and consequently also to the parts protruding into the anode groove an oscillating movement in relation to a desired position of the parts in the anode body or a rotatory motion.
  • the metal parts arranged in the groove in the anode body may have different shapes as seen in a section perpendicular to the axis of the magnetron, adapted with respect to the desired variation of frequency and with respect to the desired course of the variation of the frequency with time.
  • the shape of the movable metal parts which gives the desired variationof the frequency for a continuous rotation or uniformly oscillating movement of the metal parts in the groove.
  • the frequency of the frequency variation can be made higher than the number of cavities multiplied by the number of revolutionsper second of the rotating support if'the pitch of the .metal parts on the support is made a fraction of the pitch of the cavities,
  • Such a device is particularly advantageous for obtaining'hi h variation frequencies in .magnetrons of the kind earlier referred to providedwith thin plate shaped cavity walls.
  • V In a preferred" embodiment of a magnetronaccording to the invention the driving members for the rotatable support for the metal parts arev arranged entirely within the evacuated vessel of the magnetron. Arrangements and means for this purpose are Well known per se, i.e. from X-ray tube arrangements.
  • a magnetron device may, following the same principles as indicated above, be provided with more than one groove or series of recesses in the anode body described above with displaceable parts arranged in cooperation with the slots formed by said groove in anode body between adjacent cavities of said body.
  • said metal parts in an embodiment of a magnetron according to the invention in which the metal parts are displaceable in the grooves or slots described above in the anode body between the cavities in a direction parallel to the axis of the magnetron, said metal parts may together constitute one single tuning ring with the same section along its periphery, the filling of the grooves between the cavities varyingwith the longitudinal displacement of the ring.
  • a device according to the invention shows considerable advantages in comparison to known embodiments of tunable magnetrons in which a number of rods or radially arranged plates corresponding to the number of cavities are displaceable in the longitudinal direction of the cavity body.
  • a minute centering as well as a very exact support in the tangential direction is necessary, while said tuning ring according to the invention only asks for a good centering which can easily be obtained as it is not essential that said tuning ring bears free from the walls of the grooves.
  • a IZ-cavity anode structure comprising a cylindrical body with radial- 1y disposed vanes of otherwise conventional type and for a wave length of 3 cm.
  • Fig. 1 is a longitudinal sectional view taken through the center of a magnetron made in accordance with the principles of the invention.
  • Fig. 2 and Fig. 3 are different embodiments of metal parts, intended to be rotatably arranged in relation to the anode body with the metal parts moving in a groove in said body, forming apertures between the cavities of the anode.
  • anode body 1 is provided with a cylindrical aperture comprising interiorly extending vanes 2, which, together with the anode body 1, form an anode with twelve cavities, having openings in the direction of the circularly cylindrical space 3 within the anode in which the cathode 4 of the magnetron is arranged.
  • a ring shaped groove is cut in .the anode body such that apertures are obtained between the cavities by means of said groove.
  • a preferably insulating support 6, which may consist of' a circular ceramic disc conductive teeth 7 are secured. Said teeth'are arranged with such pitch that they all, for a certain position of the support 6, fill up, entirely or in part, the apertures 5 in the vanes between adjacent cavities.
  • Said teeth 7 may beinsulated fromeach other as shown in Fig. 2 or carried by a conducting cylinder 8, V the external diameter of which substantially corresponds to the external diameter of thering shaped groove 5 in theanode.
  • a driving means 15 for the support 6 and teeth 7 is secured to shaft 12 and arranged within the vacuum space of the magnetron as illustrated with the vessel 16 hermetically sealed to the pole piece 9.
  • the groove in the anode structure is arranged such that the apertures between the cavities is located at the parts of the cavities most distant from the centre of the anode structure.
  • the frequency variations of the device is due substantially to the influence of the teeth on the magnetic lines of force at the bottom of the cavity.
  • Corresponding grooves orapertures may instead or as well be arranged nearer to the centre of the anode structure. A successive transfer from inductive to capacitive action is obtained by successive choice of the location of the apertures -in the cavity walls nearer to centre of the anode structure.
  • an annular anode .unit of electrically conductive material having an inner face forming a substantially cylindrical space within said anode unit; a partition unit composed of a plurality of partition members of electrically conductive material arranged on said inner face of said annular anode unit and extending inwardly into said cylindrical space, said partition members being arranged spaced from each other so as to form resonator cavities between themselves; aperture means in at least one of said above units arranged along a circular line coaxial with said cylindrical space in a plane normal to the axis thereof in such a manner as to connect subsequent resonator cavities with each other; a substantially annular tuning means including conductive elements arranged spaced from the axis of said annular tuning means at the same distance as said aperture means are located from the axis of said cylindrical space; and combined supporting and rotating means arranged coaxially with said cylindrical space within said annular'anode unit and secured to said substantially annular tuning means supporting the same rotatably about its axis coaxial
  • an annular anode unit of electrically conductive material having an inner face forming a substantially cylindrical space within said anode unit; said anode unit having in said inner face thereof a face portion having a smaller diameter and a portion having a larger diameter; a parti- As alreadydescribed said teeth may be given different shape and size with respect to the desired shape of.
  • tion unit composed of a plurality of partition members of electrically conductive'material arranged on said face portion having a smaller diameter and extending inwardly into said cylindrical space, said partition members being arranged spaced from each other so as to form resonator cavities between themselves and extending axially also into that portion of said cylindrical space which is formed bysaid face portion having a larger diameter so as to' form between said partition members and said face portion of larger diameter apertures connecting said resonator cavities with each other, said apertures being arranged substantially along a circular line coaxial with said cylindrical space in a plane normal to the axis thereof; and rotary tuning means including conductive elements arranged spaced from the axis of said rotary tuning means at the same distance as said aperture means are located from the axis of cylindrical space; said rotary tuning means being rotatable about its axis coaxial with said cylindrical space so that by turning said rotary tuning means so as to vary the relative position of said conductive elements and said partition members and thus varying the free cross-sectional area of said aperture means,
  • an annular anode made of electrically conductive material and having an inside wall enclosing a substantially cylindrical space, said anode including a plurality of partition members attached to said wall and each extending radial- 1y towards the axis of said space from said wall with their inner ends equidistant from said axis, and extending axially over part of the axial length of said anode leaving a cylindrical space between the axially facing ends of said partition members and the nearest end face of said anode, so that segmental resonator cavities are formed in said anode between said partition members, said anode being formed with recesses constituting apertures connecting said cavities with each other and with said cylindrical space, said apertures being located along a first circle concentric with said axis; a rotatable tuning means mounted for rotation about said axis within said cylindrical space opposite said partition members and including a carrier member, a plurality of electrically conductive elements projecting from said carrier member towards so that saidfconductive
  • An electron discharge device as set forth in claim 3, in which the number of said electrically conductive elements of said rotatable tuning means is an integerrnultiple of the number of said resonator cavities.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Microwave Tubes (AREA)
  • Resistance Welding (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
US531389A 1954-09-01 1955-08-30 Magnetron with variable resonance frequency Expired - Lifetime US2931943A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE341575X 1954-09-01

Publications (1)

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US2931943A true US2931943A (en) 1960-04-05

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US531389A Expired - Lifetime US2931943A (en) 1954-09-01 1955-08-30 Magnetron with variable resonance frequency

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US (1) US2931943A (enrdf_load_html_response)
BE (1) BE540988A (enrdf_load_html_response)
CH (1) CH341575A (enrdf_load_html_response)
DE (1) DE1081976B (enrdf_load_html_response)
FR (1) FR1167523A (enrdf_load_html_response)
GB (2) GB540988A (enrdf_load_html_response)
NL (2) NL200109A (enrdf_load_html_response)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3343031A (en) * 1963-12-21 1967-09-19 Philips Corp Tunable electronic tube
US3365609A (en) * 1964-09-01 1968-01-23 Philips Corp Transducer for use with variable frequency magnetrons
DE2722276A1 (de) * 1976-05-21 1977-12-01 Philips Nv Abstimmbares magnetron
US4323819A (en) * 1979-05-01 1982-04-06 E M I - Varian Limited Spin-tuned magnetron
EP0238236A3 (en) * 1986-03-15 1989-05-03 Thorn Emi-Varian Limited Improvements relating to magnetrons

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3231781A (en) * 1962-08-10 1966-01-25 Sfd Lab Inc Reverse magnetron with slot mode absorber
GB2191889A (en) * 1986-06-20 1987-12-23 Emi Varian Ltd Improvements relating to spin- tuned magnetrons

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2448573A (en) * 1946-02-28 1948-09-07 Bell Telephone Labor Inc Cathode structure for electron discharge devices
US2466060A (en) * 1945-03-31 1949-04-05 Raytheon Mfg Co Electron discharge device
GB668141A (en) * 1950-08-17 1952-03-12 British Thomson Houston Co Ltd Improvements relating to magnetrons
US2607019A (en) * 1948-05-29 1952-08-12 Rca Corp Electron discharge device of the cavity resonator type
GB716677A (en) * 1952-07-15 1954-10-13 M O Valve Co Ltd Improvements in or relating to magnetrons
US2799802A (en) * 1954-04-16 1957-07-16 Litton Industries Inc Magnetron tuner device

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2506955A (en) * 1945-05-14 1950-05-09 Bell Telephone Labor Inc Tunable high-frequency circuits
BE511839A (enrdf_load_html_response) * 1951-06-07
FR1040274A (fr) * 1951-08-01 1953-10-14 Radio Electr Soc Fr Perfectionnements aux tubes pour ultra-hautes fréquences

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2466060A (en) * 1945-03-31 1949-04-05 Raytheon Mfg Co Electron discharge device
US2448573A (en) * 1946-02-28 1948-09-07 Bell Telephone Labor Inc Cathode structure for electron discharge devices
US2607019A (en) * 1948-05-29 1952-08-12 Rca Corp Electron discharge device of the cavity resonator type
GB668141A (en) * 1950-08-17 1952-03-12 British Thomson Houston Co Ltd Improvements relating to magnetrons
GB716677A (en) * 1952-07-15 1954-10-13 M O Valve Co Ltd Improvements in or relating to magnetrons
US2799802A (en) * 1954-04-16 1957-07-16 Litton Industries Inc Magnetron tuner device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3343031A (en) * 1963-12-21 1967-09-19 Philips Corp Tunable electronic tube
US3365609A (en) * 1964-09-01 1968-01-23 Philips Corp Transducer for use with variable frequency magnetrons
DE2722276A1 (de) * 1976-05-21 1977-12-01 Philips Nv Abstimmbares magnetron
US4131825A (en) * 1976-05-21 1978-12-26 U.S. Philips Corporation Ditherable and tunable magnetron comprising axially tuning and rotational tuning members
US4323819A (en) * 1979-05-01 1982-04-06 E M I - Varian Limited Spin-tuned magnetron
EP0238236A3 (en) * 1986-03-15 1989-05-03 Thorn Emi-Varian Limited Improvements relating to magnetrons

Also Published As

Publication number Publication date
CH341575A (de) 1959-10-15
GB540988A (en) 1941-11-07
NL96902C (enrdf_load_html_response)
GB799983A (en) 1958-08-13
DE1081976B (de) 1960-05-19
BE540988A (enrdf_load_html_response)
FR1167523A (fr) 1958-11-26
NL200109A (enrdf_load_html_response)

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