US2467538A - Electron discharge device - Google Patents

Electron discharge device Download PDF

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Publication number
US2467538A
US2467538A US747255A US74725547A US2467538A US 2467538 A US2467538 A US 2467538A US 747255 A US747255 A US 747255A US 74725547 A US74725547 A US 74725547A US 2467538 A US2467538 A US 2467538A
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US
United States
Prior art keywords
cathode
anode
straps
vanes
magnetron
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
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US747255A
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English (en)
Inventor
William E Shoupp
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.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
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Filing date
Publication date
Priority to BE482319D priority Critical patent/BE482319A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US747255A priority patent/US2467538A/en
Priority to GB7459/48A priority patent/GB656570A/en
Application granted granted Critical
Publication of US2467538A publication Critical patent/US2467538A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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

  • This invention relates to electron discharge devices generally referred to as magnetrons, and more particularly to tuning means for the same.
  • the present invention relates to and has for its object the tuning of a magnetron by electronic means, and more definitely tuning by injecting electrons into capacitative elementsof a magnetron thereby altering resonant frequency of the oscillating element or elements. It is common practice in magnetrons to provide ringshaped straps in an end space thereof and in the present disclosure ring-shaped coaxial straps are provided of which one strap connects alternate partitions provided between cavity resonators and of which another concentric strap connects the intervening partitions. These straps have a mutual capacitance as well as a capacity relationship to those of the anode partitions which are alternately skipped by each ring.
  • tuning is accomplished by placing a special or auxiliary cathode in the end space next the straps directed toward the associated portions of the anode partitions of the magnetron and applying a modulation voltage between said auxiliary cathode and the magnetron anode.
  • the electrons from the auxiliary cathode will be drawn toward the anode and will enter the spaces between the straps and also form a conductive path from the straps to the anode at the separated regions of straps and anode.
  • the frequency is somewhat less than the Lamor frequency, the electrons will have small radial amplitude due to the very strong magnetic field applied for magnetron operation and will travel in tight helices the general directions of which are roughly straight paths.
  • the invention contemplates obtaining frequency shift in proportion to electron current along a short path and readily controlled modulation power supply therefor.
  • Figure 1 is an axially longitudinal section of a magnetron showing my improved tuning means therein;
  • Figure 2 is a plan of the construction of Figure l, but with the cover or end plate removed, as on line IIII of Figure 1;
  • Figure 3 is another cross-section as on line III-III of Figure l
  • Figure 4 is a further cross-section as on line IVIV of Figure 1;
  • Figures 5 and 6 are enlarged detail sections of a portion of the auxiliary or tuning cathode at non-emitting and electron emitting areas respectively and showing an associated portion of the anode, as on lines V-V and VI-V I respectively of Figure 3; and
  • Figure 7 is a further sectional view similar to Figure 6 at another emitting portion of the oathode taken on line VIIVII of Figure 3.
  • the reference numeral l0 designates a cylindrical metallic magnetron body, the ends whereof have cover or end plates ll sealed thereon that the interior may be evacuated.
  • the usual magnetron anode structure I2 of generally cylindrical shape but shorter than the outer part of the body so as to provide end spaces [3 between the anode and said end plates II.
  • the anode structure is axially hollow to provide a cathode cavity I4 and radiating from the cathode cavity are a plurality of cavities l5 constituting cavity resonators each having, in the form shown, a cylindrical portion having a longitudinal constricted capacitative slot l6 constituting a lateral opening from the cylindrical portion of the cavity into the hollow central part of cathode chamber-of the mag-
  • the structure provides a plurality of partitions or vanes I"! radiating from the central or cathode cavity l4 intervening between and at least in part forming walls for the several cavities.
  • double ring straps identified as outer or larger strap I8 and,
  • An indirectly heatedcathode 28 passes axially through the cathode cavity l4, adequately spaced from the anode-and supported as usual from leadin rods 2
  • An output loop 22 is situated in one of the resonant cavities l5, passing out through the side wall of the body In in accordance with usual practice.
  • the size and shape of the magnetron body, the end spaces, anode, cathode and leads above described are preferably all substantially in accordance with prior art practice, in consequence of which the pole pieces of the magnet, not shown, will have the same or closely the same relation to the magnetron and its anode as exists in magnetrons as heretofore used.
  • an auxiliary cathode 23 of generally ring or doughnut shape, is shown concentrically situated in said end space l3, and in this instance, since straps areprovided at both ends of the anode, an auxiliary cathode 23 is located in each of said spaces.
  • the said auxiliary cathode occupies a position circularly opposing the cylindrical end edges of the straps l8, l9 and slotted portions of the anode and preferably'has a radial width substantially equal to the radiallength of said slots.
  • the auxiliary cathode overlies or opposes those portions of the anode partitions or vanes inter" vening between the straps and also extra margins radially outside of the outer strap and radially inside the inner strap. These extra margins of overlap of the'auxiliary cathode to the straps are atleast as great as clearance distance radially .uitoward t eanode. end andaflan ed t oidal i the torus.
  • the toroidal wall is split radially at one part thereof so as to provide separated ends 21 therefor which face toward each other.
  • a heater 28 Coaxially within said toroidal wall 25 and spaced from the flat wall 24 is a heater 28, here shown as a single-strand resistance wire, the ends of which protrude from the two said ends 21 of One of said ends of the heater 28 is connected to the auxiliary cathode casing andthe other end of said heater is connected to a lead-in rod or wire '29 the inner end of which is shown protruding radially of the magnetron end space 3 to a location between ends of the auxiliary cathode casing and out of contact therefrom.
  • the interior of the torus or auxiliary cathode casing contains a suitable electrical insulation material 30 for maintaining desired electrical isolation of the heater, except where attachedat its one end, from said casing of the auxiliary cathode.
  • auxiliary cathode casing Support for and electrical connection to the auxiliary cathode casing is obtained by another radially disposed lead-in rod or wire 3 I.
  • a partial sleeve 32 is shown integral with and projecting radially from said torus and this Sleeve is in turn soldered or otherwise secured on the end portion of the lead-in rod or wire 3
  • constitutes electrical connection both for the auxiliary cathode and ,for one end of the heater.
  • the other or first-mentioned. lead-in rod 29 connects only with the other end of the heater so as to obtain a complete heater circuit to the exterior. Insulative mounting and passage of both lead-in wires at each end of the magnetron is alike and accords with prior art practice for lead-in wires as to construction, so requires no elaboration herein.
  • auxiliary cathode On the face of the flat wall 24 of the auxiliary cathode directed toward the anode, at the areas directly opposing the ends of the partitions or vanes ll of the anode in the region of an opening toward said straps l8, l9, are cups 33 in the bottoms or upon the basal end walls of which is pro- .vided material 34 copiously emissive of electrons.
  • the cups are welded or otherwise secured at their basal or end walls against the fiat wall 24 and thus confine emissive areas of the auxiliary cathodes to the isolated patches of the emissive material.
  • any suitable emissive materials may be employed, of which alkaline earths, such as barium or stron-. tium or their oxides are examples.
  • the side Walls of cups 33 form a continuous rim for each, projecting from the basal end wall around the patch of emissive material and constitute a focusing collar for the electrons.
  • the successive cups 33 are correspondingly staggered so each will oppose the rings and clearance space for the successive vanes of the circular series.
  • Frequency modulation is, therefore, in consequence of the structure described above, produced electronically by means of a separate modulation power supply used in conjunction with the auxiliary cathode, and without need for any moving mechanical parts in the magnetron.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing cavity resonators therebetween, straps extending between said vanes and constituting capacitative elements, a main cathode in said cathode cavity, and an auxiliary cathode contiguous to but outside of and directed toward said capacitative elements so as to introduce electrons between said elements and thereby change the capacitance and oscillation frequency.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing cavity resonators therebetween, straps extending between said vanes and constituting capacitative elements, a main cathode coaxially in said cathode cavity from which electrons will be emitted radially toward the anode, and an auxiliary cathode having an emitting area directed toward an end of the anode and toward said straps for emission of electrons the general paths whereof are toward the anode and substantially parallel to the main cathode and directed between said capacitative elements.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing cavity resonators therebetween radiating from said cathode cavity, coaxial straps extending between said vanes and constituting capacitative elements, a main cathode in said cathode cavity, and an auxiliary ring-shaped cathode opposite to and overlying end edges of said straps coaxial therewith and having an electron emitting area for directing electrons between said capacitative elements.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing cavity resonators therebetween radiating from said cathode eavity, coaxial straps extending one between alternate vanes and the other between intervening vanes and constituting each with a part of said vanes and with each other capacitative elements, a main cathode in said cathode cavity, and an auxiliary ring-shaped cathode overlying an end edge of said straps coaxial therewith and confined substantially to overlying said capacitative elements.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing a circular series of a number of cavity resonators therebetween radiating from said cathode cavity and having an end space at an end of said anode, coaxial straps extending across said radiating vanes one with clearance at its inside at the end next said end space with alternate vanes and the other with clearance at its outside with the intervening vanes and constituting with the vane with which it has clearance and between each other capacitative elements, a main cathode in said cathode cavity, and an auxiliary ring-shaped cathode in said end space coaxial with said cathode cavity and overlying said straps and vanes and said inside and outside clearances, the ends of the resonators being otherwise open to said end space.
  • a magnetron having an anode providing a cathode cavity and radiating vanes providing a circular series of a number of cavity resonators therebetween radiating from said cathode cavity and having an end space at an end of said anode, coaxial straps extending across said radiating vanes one with clearance at its inside at the end next said end space with alternate vanes and the other with clearance at its outside with the intervening vanes and constituting with the vane with which it has clearance and between each other capacitative elements, a main cathode in said cathode cavity, and an auxiliary ring-shaped cathode in said end space coaxial with said cathode cavity and overlying said straps and vanes and said inside and outside clearances, the ends of the resonators being otherwise open to said end space, and said auxiliary cathode having a plurality of equally spaced electron emissive patches and focusing means equal in number and spacing to the number of vanes and located opposite said vanes.
  • a magnetron having an anode providing a cathode cavity and a circular series of a number of evenly spaced vanes and cavity resonators radiating therefrom and having end spaces at opposite ends of said anode, coaxial straps extending one in contact with alternate vanes and the other in contact with intervening vanes and each strap successively out of contact and having clearance spaces from the vanes between the ones with which it is in contact constituting thereat and constituting between straps capacitative elements next each of said end spaces, a main cathode in said cathode cavity, and an auxiliary ringshaped cathode in each of said end spaces coaxial with said cathode cavity and directly opposite said straps and clearance spaces, the ends of the resonators being substantially otherwise open to said end spaces, and said auxiliary cathode having a plurality of equally spaced electron emissive patches and focusing collars equal in number to the said number of vanes, said patches being successively staggered and directly overlying the vanes from and including the clearance space to

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US747255A 1947-05-10 1947-05-10 Electron discharge device Expired - Lifetime US2467538A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE482319D BE482319A (it) 1947-05-10
US747255A US2467538A (en) 1947-05-10 1947-05-10 Electron discharge device
GB7459/48A GB656570A (en) 1947-05-10 1948-03-11 Improvements in or relating to magnetrons

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US747255A US2467538A (en) 1947-05-10 1947-05-10 Electron discharge device

Publications (1)

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US2467538A true US2467538A (en) 1949-04-19

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US747255A Expired - Lifetime US2467538A (en) 1947-05-10 1947-05-10 Electron discharge device

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BE (1) BE482319A (it)
GB (1) GB656570A (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2611003A (en) * 1951-02-21 1952-09-16 Rca Corp Beam alignment device
US2810856A (en) * 1953-09-21 1957-10-22 Robert R Reed System of magnetron frequency modulation
US2826719A (en) * 1955-04-01 1958-03-11 Rca Corp Magnetron
US3069595A (en) * 1960-08-22 1962-12-18 Sylvania Electric Prod Detuning interfering magnetron modes
US5084651A (en) * 1987-10-29 1992-01-28 Farney George K Microwave tube with directional coupling of an input locking signal

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2611003A (en) * 1951-02-21 1952-09-16 Rca Corp Beam alignment device
US2810856A (en) * 1953-09-21 1957-10-22 Robert R Reed System of magnetron frequency modulation
US2826719A (en) * 1955-04-01 1958-03-11 Rca Corp Magnetron
US3069595A (en) * 1960-08-22 1962-12-18 Sylvania Electric Prod Detuning interfering magnetron modes
US5084651A (en) * 1987-10-29 1992-01-28 Farney George K Microwave tube with directional coupling of an input locking signal

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Publication number Publication date
BE482319A (it)
GB656570A (en) 1951-08-29

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