US3727097A - Magnetrons - Google Patents

Magnetrons Download PDF

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Publication number
US3727097A
US3727097A US00166934A US3727097DA US3727097A US 3727097 A US3727097 A US 3727097A US 00166934 A US00166934 A US 00166934A US 3727097D A US3727097D A US 3727097DA US 3727097 A US3727097 A US 3727097A
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US
United States
Prior art keywords
magnetron
transducer
piezo
electric
cathode
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
US00166934A
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English (en)
Inventor
B 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 US3727097A publication Critical patent/US3727097A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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

Definitions

  • ABSTRACT In a magnetron in which tuning is effected by a movable conductive member adjacent one end face of the anode block whose position is controlled by a piezoelectric transducer inside the envelope of the magnetron the transducer is shielded from the cathode by a layerof glass and/or a metal shield, thus reducing the deterioration of the transducer.
  • This invention relates to magnetrons and more particularly to magnetrons of the kind in which tuning is effected by a conductive member adjacent one end face of the anode block of and movable axially towards and away from said face under the control of a piezoelectric transducer within the evacuated envelope of the magnetron. 7
  • the object of this invention is to provide improved magnetrons of the kind referred to in which the tendency for deterioration of the piezo-electric transducer to occur as above mentioned is reduced.
  • a magnetron of the kind referred to means are provided for shielding otherwise exposed regions of piezo-electric material forming said transducer from said cathode.
  • the shielding means may take the form of a screen mounted in front of the transducer facing thecathode or it may take the form of a deposit of insulating material on otherwise exposed regions of piezoelectricmaterial facing the cathode. In preferred embodiments of the invention both of the above mentioned forms of screening are provided together.
  • the deposit of insulating material is preferably provided to cover all of the edge surfaces of the'pie zo electric transducer so that no region of piezo-electric material is exposed.
  • the insulating material is glass.
  • the nature of the glass is not critical but a lead'glass is preferred in view of its low melting point and goodwetting properties.
  • a preferred lead glass has the following mix ReadLead 440 gm.
  • the glass film' is suitably approximately thick.
  • the conductive tuning member is mounted on an arm (with which it may be integral) projecting from the end of a piezoelectric transducer which in turn is mounted in cantilever fashion from a relatively massive mounting block, preferably said screen is carried on said arm.
  • a heat conductor is connected between said arm and said mounting block in order to conduct away heat absorbed by said screen and said tuning member.
  • Preferred materials are copper for the arm, tuning member screen and heat conductor and kovar (nickelcopper-iron) for the mounting block.
  • the transducer is.
  • the transducer is of the multimorph type.
  • FIG. 1 is a longitudinal section of part of a magnetron of the unstrapped rising sun type tunable by means of an axially movable conductive member.
  • FIG. 2 is a diagram illustrating the alignment of the movable tuning member of FIG. 1 with the cavities in the anode block of the magnetron of FIG. 1.
  • FIG. 3 is a perspective view of a piezo-electric birmorph transducer arrangement provided in accordance with the present invention.
  • FIG. 4 is a part plan view of an alternative configuration for the movable tuning member of FIG. I.
  • FIG. 5 is a perspective view of a piezo-electric multimorph transducer arrangement provided in accordance with the present invention and FIG. 6 is a section of one of the piezo-electric multimorph transducers used in the arrangement of FIG. 5.
  • the magnetron consists of an unstrapped rising sun anode block 1 having the usual alternate arrangement of large cavities 2 and small cavities 3.
  • the anode block 1 has an axial bore 4 in which is mounted a cathode 5.
  • the pole pieces mounted on either side of the anode block 1 are referenced 6 and 7'.
  • Mounted between one face of the anode block 1 and the pole piece 7 is a tuning member 8 controlled (by the piezo-electric transducer not proximately with the end walls 10 of the larger cavities 2 whilst the inner circumference l1 aligns approximately with the end walls 12 of the smaller cavities 3.
  • each portion of the tuning member 8 lying over a larger cavity acts as a short circuited turn, the effect of which on the cavity increases as the member 8 is moved near to the face of the anode block 1 to increase the frequency of oscillation, and decreases as the member 8 is moved away from the face of the anode block '1 to decrease the frequency of oscillation.
  • the annular tuning member 8 is formed at the end of, and as part of, a conductive arm 13 of copper.
  • the arm 13 is brazed to the underside of an projects from the end of a piezo-electric transducer 14 of the bimorph type, as known per se.
  • the transducer M which consists of two strips of piezo-electric material one on top of the other is mounted in cantilever fashion, on a conductive mounting block 15 of kovar (metal-copper-iron).
  • Connecting leads Hand 17, for applying energizing potential to the bimorph transducer are passed out through feed-through seals 1% and 19 in a base member 20 which in turn is sealed into the walls (not shown) of the magnetron.
  • edges 22 of the transducer and the recess 23 formed by the edge of the upper sheet of piezo-electric material and the upper surface of the lower sheet of piezo-electric material is coated with a thin film of glass, as represented by shading, to cover the otherwise exposed regions of piezo-electric material in the upper 'and 0.003 inch, having a'mix as follows:
  • asheet 24 of copper is attached with the arm 13 to the lower sheet of piezo-electric material, the end of the sheet 24 being turned up through 90 to form a screen 25 in front of the edge of the transducer facing the magnetron-cathode 5.
  • a heat conductive strap of copper- is connected between the arm 13 and'screenforming sheet 24 on the one hand and the mounting block'15 on the other hand.
  • the tuning member as an outer boundary of castellated form each extension of the tuner ring 8 covering part of one of the larger cavities in'the magnetron block 9.
  • This arrangement provides a tuning rate which is greater than that of the arrangement shown in FIG. 2 in which a plain an-' nulus has the tuning member.
  • each of the multimorph piezo-electric transducers of FIG. 5 consists of. an upper electrode 27 and a lower electrode 28 provided on a piezo-electric ceramic body .29. Within the piezoelectric ceramic-body 29 c'emtre electrodes 30 are-provided which pass through holes 31. What otherwise would be free spacebetween a wire 30 and the side wall of a hole 31 is occupied by graphite material 32.
  • a magnetron of thetype included an anode block having'an end face and provided with bore and cavity formations opening onto said end I face, a cathode in said bore, and said magnetrondefining an evacuated region at and surrounding said end faceand in communication with saidbore andcavity formations from said endface in response to voltage fluctuations applied to said piezo-electric transducer; and means for shielding the piezo-electric material of saidtransducer, and especially any boundary region between two portions of pi'ezo-electric material forming said transducer, from said cathode.
  • a magnetron as claimed in claim 1 and wherein said means for shielding comprises a screen mounted in front of the transducer facing the cathode.
  • a magnetron as claimed in claim 1 and wherein said means for shielding comprises a deposit of insulating material on otherwise exposed regions of said piezo-electric material faqing the cathode.
  • a magnetron as claimed in claim 1 and wherein said means for shielding comprises a screen mounted in front of the transducer facing the cathode and a deposit of insulating material on otherwise exposed regions of said piezo-electric material facing the cathode.
  • a piezo-electric transducer disposed in said evacu ated region; a conductive member carried by said piezo-electric transducer for axial movement toward and away sorbed by said screen and said tuning member.

Landscapes

  • Control Of High-Frequency Heating Circuits (AREA)
  • Glass Compositions (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
  • Microwave Tubes (AREA)
US00166934A 1970-08-06 1971-07-28 Magnetrons Expired - Lifetime US3727097A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3808170 1970-08-06

Publications (1)

Publication Number Publication Date
US3727097A true US3727097A (en) 1973-04-10

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ID=10401048

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US00166934A Expired - Lifetime US3727097A (en) 1970-08-06 1971-07-28 Magnetrons

Country Status (8)

Country Link
US (1) US3727097A (enExample)
AU (1) AU456610B2 (enExample)
CA (1) CA947427A (enExample)
DE (1) DE2139582C3 (enExample)
FR (1) FR2104095A5 (enExample)
GB (1) GB1349354A (enExample)
NL (1) NL7110464A (enExample)
SE (1) SE366609B (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4186324A (en) * 1978-05-11 1980-01-29 Schaevitz Engineering Linear accelerometer with piezoelectric suspension
EP0279112A1 (en) * 1987-01-21 1988-08-24 Eev Limited Tunable magnetrons
US5017266A (en) * 1988-01-27 1991-05-21 Stanford University Method of making an integrated scanning tunneling microscope

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2036418B (en) * 1978-12-05 1983-01-19 English Electric Valve Co Ltd Magnetrons
JPS5613719U (enExample) 1979-07-13 1981-02-05
FR2581254B1 (fr) * 1985-04-30 1988-09-16 Onera (Off Nat Aerospatiale) Dephaseur en micro-ondes, notamment en ondes millimetriques, a commande piezoelectrique et antennes l'utilisant
FR2581255B1 (fr) * 1985-04-30 1989-01-06 Onera (Off Nat Aerospatiale) Dephaseur en micro-ondes, notamment en ondes millimetriques, a commande piezoelectrique
GB2242308B (en) * 1990-02-06 1994-03-02 Eev Ltd Magnetrons
GB9002593D0 (en) * 1990-02-06 1990-10-17 Eev Ltd Magnetrons

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752495A (en) * 1951-05-08 1956-06-26 Rca Corp Ferroelectric frequency control
US3028522A (en) * 1954-07-12 1962-04-03 Marshall C Pease Magnetrons
US3087124A (en) * 1958-05-29 1963-04-23 Raytheon Co Feedback system for reed modulated magnetrons
US3334261A (en) * 1965-10-24 1967-08-01 Sylvania Electric Prod High pressure discharge device having a fill including iodine mercury and at least one rare earth metal
US3440565A (en) * 1966-03-17 1969-04-22 Westinghouse Electric Corp Sensor for detection of frequency of a reed modulated magnetron
US3478247A (en) * 1967-06-12 1969-11-11 Litton Precision Prod Inc Microwave tuner having a rapid tuning rate
US3478246A (en) * 1967-05-05 1969-11-11 Litton Precision Prod Inc Piezoelectric bimorph driven tuners for electron discharge devices

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752495A (en) * 1951-05-08 1956-06-26 Rca Corp Ferroelectric frequency control
US3028522A (en) * 1954-07-12 1962-04-03 Marshall C Pease Magnetrons
US3087124A (en) * 1958-05-29 1963-04-23 Raytheon Co Feedback system for reed modulated magnetrons
US3334261A (en) * 1965-10-24 1967-08-01 Sylvania Electric Prod High pressure discharge device having a fill including iodine mercury and at least one rare earth metal
US3440565A (en) * 1966-03-17 1969-04-22 Westinghouse Electric Corp Sensor for detection of frequency of a reed modulated magnetron
US3478246A (en) * 1967-05-05 1969-11-11 Litton Precision Prod Inc Piezoelectric bimorph driven tuners for electron discharge devices
US3478247A (en) * 1967-06-12 1969-11-11 Litton Precision Prod Inc Microwave tuner having a rapid tuning rate

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4186324A (en) * 1978-05-11 1980-01-29 Schaevitz Engineering Linear accelerometer with piezoelectric suspension
EP0279112A1 (en) * 1987-01-21 1988-08-24 Eev Limited Tunable magnetrons
US5017266A (en) * 1988-01-27 1991-05-21 Stanford University Method of making an integrated scanning tunneling microscope
US5129132A (en) * 1988-01-27 1992-07-14 Board Of Trustees Of The Leland Stanford Jr., University Method of making an integrated scanning tunneling microscope
US5248912A (en) * 1988-01-27 1993-09-28 Stanford University Integrated scanning tunneling microscope

Also Published As

Publication number Publication date
GB1349354A (en) 1974-04-03
AU456610B2 (en) 1974-12-19
SE366609B (enExample) 1974-04-29
AU3188371A (en) 1973-02-08
NL7110464A (enExample) 1972-02-08
DE2139582B2 (de) 1973-07-12
CA947427A (en) 1974-05-14
DE2139582A1 (de) 1972-02-10
FR2104095A5 (enExample) 1972-04-14
DE2139582C3 (de) 1974-02-14

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