US3441796A - Magnetrons having cyclically varying frequencies - Google Patents

Magnetrons having cyclically varying frequencies Download PDF

Info

Publication number
US3441796A
US3441796A US566612A US3441796DA US3441796A US 3441796 A US3441796 A US 3441796A US 566612 A US566612 A US 566612A US 3441796D A US3441796D A US 3441796DA US 3441796 A US3441796 A US 3441796A
Authority
US
United States
Prior art keywords
rotor
teeth
magnetron
strap
straps
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
US566612A
Other languages
English (en)
Inventor
Brian Frederick Cooper
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
English Electric Valve Co 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 English Electric Valve Co Ltd filed Critical English Electric Valve Co Ltd
Application granted granted Critical
Publication of US3441796A publication Critical patent/US3441796A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • H01J23/18—Resonators
    • H01J23/20—Cavity resonators; Adjustment or tuning thereof
    • 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
    • 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
    • H01J23/22—Connections between resonators, e.g. strapping for connecting resonators 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

  • a strapped magnetron having each one of a pair of alternate anode connecting straps provided with discrete surfaces to cooperate with the surfaces of the other of the pair to constitute inter-strap capacitances.
  • the magnetron is provided with a rotor having discrete conductive parts arranged so that, upon rotation, the parts traverse the dielectric spaces of, and vary the values of, the capacitances.
  • connection strapping together alternate anodes are connected together by at least one connection and the remaining alternate anodes are connected together at least by another connection.
  • These connections are known as straps and in the most widely used strapped magnetrons they are in the form of arcuate connections at the end or ends of the anode block (commonly at both ends) each connection being usually in the form of a ring concentric with the axis and connected to the alternate anodes which it straps together.
  • any connection strapping together alternate anodes may be termed a-strap.
  • the oscillating frequency of a magnetron operating in the mode depends inter alia upon the capacity between the pair of straps one of which connects together one set of alternate anodes and the other of which connects together the other set of alternate anodes.
  • the present invention takes advantage of this fact to provide improved rapidly tunable magnetrons.
  • each of a pair of alternate anode-connecting straps of a magnetron is provided with a plurality of discrete surfaces positioned to cooperate with the surfaces of the other to constitute a plurality of inter-strap capacitances distributed along the strap length and a rotor having a plurality of discrete conductive parts is so mounted and arranged that, upon rotation, said parts in turn traverse the dielectric spaces of said capacitances to vary the values thereof as they pass.
  • each of the straps is provided with the same number of projecting teeth, those on one strap projecting towards those on the other.
  • the rotor may have the same number of teeth each of which, when aligned with and between two opposed teeth, one on each strap, almost fills the space between said two opposed teeth but contacts with neither.
  • the rotor may have the same number of holes each of which, when aligned with and between two opposed teeth, one on each strap, leaves the space between said two opposed teeth, unobstructed, the material between adjacent holes being able to pass between said teeth without contacting with either.
  • the two straps may be rings mounted outwardly of one end of the magnetron anode block in planes perpendicular to the magnetron axis with the teeth projecting in directions parallel to said axis, the axis of rotation of the rotor being coincident with said axis.
  • the two straps may be sleeve shaped and mounted outwardly of one end of the magnetron anode block, with teeth projecting radially with respect to the magnetron axis, the axis of rotation of the rotor being again coincident with said axis.
  • the rotor and the bearings therefor are inside the evacuated envelope of the magnetron, the rotor being adapted to be rotated by a rotating magnetic or electromagnetic field applied by means lying outside the envelope.
  • FIGURE 1 shows one embodiment
  • FIGURES 2, 3 and 4 show another embodiment.
  • FIGURE 1 is a diagrammatic diametrical view of a magnetron in accordance with this invention, cut diametrically through the anode block.
  • the customary central cathode is represented at 1, 2 being the usually so-called end hats.
  • the magnetron illustrated is of the vane type and has an anode block comprising radial vanes of which two appear at 3.
  • At one end of the anode block are two ring straps 4 and S of usual construction and arrangement, the strap 4 interconnecting one set of alternate vanes (anodes) and the strap 5 interconnecting the other set of alternate vanes.
  • each of the rings 7 and 9 is provided with a like plurality of teeth 10 or 11 which project towards one another in directions parallel to the magnetron axis and are situated opposite one another. As will be apparent each pair of opposed teeth provides a capacitance, the spacing of the electrodes of which is the spacing between the adjacent ends of said teeth. Between the two rings 7 and 9 is mounted an annular disclike rotor portion 12' of conductive material.
  • the rotor generally referred to by the numeral 12 and including each of the rotatable parts within the envelope 20 connected with the rotatable disc 12', is mounted in bearings providing an axis of rotation coincident with the magnetron axis.
  • the rotor portion 12 is provided with the same number of teeth 13 as there are on each of the rings 7 and 9, each tooth projecting from both sides of the rotor so that when the said rotor is in the position shown in FIGURE 1 and each of its teeth is aligned between a pair of opposed teeth, one on each of the rings 7 and 9, the capacitance between said opposed teeth is materially changed by the presence of the rotor tooth.
  • a convenient drive arrangement comprises a three-phase winding outside the envelope, the rotor being, in effect, the rotor of a conventional eddy current AC. motor conventionally employed to effect rotation of a conductive disc-like rotor.
  • the invention provides the great advantage that for each rotation of the rotor there will be a number of cycles of frequency change equal to the number of teeth in the rotor-assuming that the rotor and each of the two rings has the same number of teethand accordingly the number of cycles of frequency change in each rotation of the rotor can be made very large indeed.
  • a high rate of tuning variation may therefore be obtained with only a relatively small speed of rotation of the rotor.
  • FIGURES 2, 3 and 4 A construction of this nature is shown in FIGURES 2, 3 and 4 in which like references denote like parts in FIGURE 1.
  • FIGURE 2 is a diagrammatic view of the same nature as FIGURE 1 while FIG- URES 3 and 4 are part-views to a larger scale.
  • FIGURE 2 there is provided at one end of the anode block a sleeve-like outer strap 17 having spaced teeth which in this case project radially inward.
  • FIGURE 3 shows part of the strap 17 with its teeth 10 in a broken-away perspective view.
  • the strap 17 connects one set of alternate vanes.
  • Adjacent and inwardly of the strap 17 is a similar sleeve-like strap 19 which connects the remaining alternate vanes of the magnetron.
  • the strap 19 has radially projecting teeth 11' on its outer surface, each tooth 11' being opposite a tooth 10.
  • a sleevelike rotor 112 Projecting down between the teeth is the open end of a sleevelike rotor 112 which has as many holes 13 (in the form of rectangular slots) as there are teeth in each of the straps 17 and 19.
  • the slots 13 are arranged in a ring round the rotor 112the rotor is shown in broken-away perspective view in FIGURE 4and the arrangement is such that in one position of the rotor each of the teeth 13 lies between an opposed pair of teeth 10', 11.
  • the straps 17 and 19 and the rotor 112 are all coaxial, the axis of rotation of the rotor being coincident with the axis of the magnetron.
  • the inter-strap capacity is at a minimum when the holes 13 are radially aligned with the teeth 10 and 11 and at a maximum when each of said holes is midway between two successive pairs of opposed teeth.
  • a strapped magnetron comprising a cathode, an anode having cavity defining projections thereon, anodeconnecting straps connecting together alternate ones of said projections, said straps having capacitance means thereon for providing inter-strap capacitances distributed along the length of said straps and including discrete opposed surfaces on each of said straps, a rotatable rotor having a plurality of capacitance varying discrete conductive parts thereon positioned between said straps for movement with rotation of said rotor to vary said interstrap capacitances during movement thereof.
  • each of the straps has thereon a number of projecting teeth, each strap being provided with the same number of projecting teeth, the teeth on one strap projecting towards the teeth on the remaining strap.
  • a magnetron as claimed in claim 2 wherein the rotor has therein a number of holes, said rotor having the same number of holes as there are teeth in each strap, each of said holes, when aligned with and between two opposed teeth, one on each strap, leaving the space between said two opposed teeth unobstructed, the material of said rotor between adjacent holes being passable between said teeth without contacting with either of said opposed teeth.
  • a magnetron as claimed in claim 1 including an evacuated envelope, said rotor being rotatably mounted inside the evacuated envelope and means lying outside the envelope for applying a rotating field to the interior thereof for rotating said rotor.
  • a strapped magnetron including a central cathode and an annular anode having radially inwardly projecting cavity defining portions extending toward said central cathode; strap means interconnecting ones of said inwardly projecting portions including a first member connected with a member of said inwardly projecting portions and a second member connected with a further number of said inwardly projecting portions, said first and second members being coaxial and proximate and having thereon a plurality of circularly arranged means for establishing capacitive coupling between said first and second members, said magnetron further comprising rotatable rotor means coaxially located between said first and second members and defining a plurality of circularly arranged discrete capacitance varying means movable between said first and second members upon rotation of said rotor for varying the capacitive coupling of said circularly arranged means for establishing capacitive coupling and for varying the output frequency of said magnetron a predetermined number of times per rotation of said rotor.

Landscapes

  • Microwave Tubes (AREA)
  • Control Of High-Frequency Heating Circuits (AREA)
US566612A 1965-08-09 1966-07-20 Magnetrons having cyclically varying frequencies Expired - Lifetime US3441796A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB33991/65A GB1078508A (en) 1965-08-09 1965-08-09 Improvements in or relating to magnetrons

Publications (1)

Publication Number Publication Date
US3441796A true US3441796A (en) 1969-04-29

Family

ID=10359989

Family Applications (1)

Application Number Title Priority Date Filing Date
US566612A Expired - Lifetime US3441796A (en) 1965-08-09 1966-07-20 Magnetrons having cyclically varying frequencies

Country Status (6)

Country Link
US (1) US3441796A (enrdf_load_stackoverflow)
CH (1) CH447399A (enrdf_load_stackoverflow)
DE (1) DE1541002A1 (enrdf_load_stackoverflow)
FR (1) FR1498510A (enrdf_load_stackoverflow)
GB (1) GB1078508A (enrdf_load_stackoverflow)
NL (1) NL6611176A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899715A (en) * 1972-06-22 1975-08-12 English Electric Valve Co Ltd Magnetron with rotatable tuning means
US3904919A (en) * 1974-05-06 1975-09-09 Varian Associates Rotary tuner for a circular electric mode crossed field tube
US3914644A (en) * 1974-04-18 1975-10-21 Varian Associates Rotary tuner for circular electric mode crossed field tube
US3932787A (en) * 1973-11-07 1976-01-13 E M I - Varian Limited Tunable coaxial magnetrons
US4131825A (en) * 1976-05-21 1978-12-26 U.S. Philips Corporation Ditherable and tunable magnetron comprising axially tuning and rotational tuning members
US4143300A (en) * 1976-09-16 1979-03-06 E M I-Varian Limited Spin tuned magnetrons
EP0018724A1 (en) * 1979-05-01 1980-11-12 Thorn Emi-Varian Limited Spin-tuned magnetron
US4555680A (en) * 1983-07-05 1985-11-26 M/A-Com, Inc. Magnetron tuned programmably using step motor
US4604587A (en) * 1983-08-05 1986-08-05 U.S. Philips Corporation Tunable magnetron with internal tuning motor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2192310B (en) * 1984-06-14 1988-05-25 Airtech Ltd Tunable rf cavity device

Citations (8)

* 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
US2542899A (en) * 1944-11-30 1951-02-20 Raytheon Mfg Co Cavity resonator electron discharge device
US2666165A (en) * 1946-01-03 1954-01-12 Hutchinson Franklin Tunable magnetron oscillator
US2851633A (en) * 1951-06-07 1958-09-09 Csf Multi-cavity resonant circuits
US3247421A (en) * 1961-11-15 1966-04-19 Philips Corp Tunable magnetron
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
US3379925A (en) * 1962-12-24 1968-04-23 Raytheon Co Tunable magnetron having a capacitive transducer magnetically coupled to the tuning member

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542899A (en) * 1944-11-30 1951-02-20 Raytheon Mfg Co Cavity resonator electron discharge device
US2506955A (en) * 1945-05-14 1950-05-09 Bell Telephone Labor Inc Tunable high-frequency circuits
US2666165A (en) * 1946-01-03 1954-01-12 Hutchinson Franklin Tunable magnetron oscillator
US2851633A (en) * 1951-06-07 1958-09-09 Csf Multi-cavity resonant circuits
US3247421A (en) * 1961-11-15 1966-04-19 Philips Corp Tunable magnetron
US3379925A (en) * 1962-12-24 1968-04-23 Raytheon Co Tunable magnetron having a capacitive transducer magnetically coupled to the tuning member
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

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3899715A (en) * 1972-06-22 1975-08-12 English Electric Valve Co Ltd Magnetron with rotatable tuning means
US3932787A (en) * 1973-11-07 1976-01-13 E M I - Varian Limited Tunable coaxial magnetrons
US3914644A (en) * 1974-04-18 1975-10-21 Varian Associates Rotary tuner for circular electric mode crossed field tube
US3904919A (en) * 1974-05-06 1975-09-09 Varian Associates Rotary tuner for a circular electric mode crossed field tube
US4131825A (en) * 1976-05-21 1978-12-26 U.S. Philips Corporation Ditherable and tunable magnetron comprising axially tuning and rotational tuning members
US4143300A (en) * 1976-09-16 1979-03-06 E M I-Varian Limited Spin tuned magnetrons
EP0018724A1 (en) * 1979-05-01 1980-11-12 Thorn Emi-Varian Limited Spin-tuned magnetron
US4323819A (en) * 1979-05-01 1982-04-06 E M I - Varian Limited Spin-tuned magnetron
US4555680A (en) * 1983-07-05 1985-11-26 M/A-Com, Inc. Magnetron tuned programmably using step motor
US4604587A (en) * 1983-08-05 1986-08-05 U.S. Philips Corporation Tunable magnetron with internal tuning motor

Also Published As

Publication number Publication date
FR1498510A (fr) 1967-10-20
GB1078508A (en) 1967-08-09
DE1541002A1 (de) 1969-07-24
CH447399A (fr) 1967-11-30
NL6611176A (enrdf_load_stackoverflow) 1967-02-10

Similar Documents

Publication Publication Date Title
US3441796A (en) Magnetrons having cyclically varying frequencies
US2408237A (en) Tunable magnetron
US2679615A (en) Electron discharge device
US2435984A (en) Tunable magnetron
US3412285A (en) Coaxial magnetron with rotatable tuning means
US2481171A (en) Electron discharge device
US2496500A (en) Electron discharge device
US3121822A (en) Circuits for unimoding crossed field devices
US3176188A (en) Mixed lines crossed fields oscillator or amplifier
US3904919A (en) Rotary tuner for a circular electric mode crossed field tube
US2546870A (en) High-frequency electrical oscillator
US3343031A (en) Tunable electronic tube
US2529950A (en) Tunable electron discharge device
US2931943A (en) Magnetron with variable resonance frequency
US3379925A (en) Tunable magnetron having a capacitive transducer magnetically coupled to the tuning member
US3121820A (en) Single mode amplifier or oscillator
US2899603A (en) Tunable magnetron
US2450023A (en) Electron discharge device of the magnetron type
GB1505123A (en) Rotary tuner for circular electric mode crossed field tub
US2816248A (en) Tunable interdigital magnetrons
US2462698A (en) Electrical discharge device
US2559604A (en) Electron discharge device
US2632131A (en) Tunable magnetron
US3354347A (en) Traveling-wave tube having lossy material walls separating adjacent oscillation suppression resonant cavities coupled to slow-wave structure interaction cells
US2644106A (en) Tuning and strapping mechanism for magnetrons