US3914644A - Rotary tuner for circular electric mode crossed field tube - Google Patents

Rotary tuner for circular electric mode crossed field tube Download PDF

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Publication number
US3914644A
US3914644A US461835A US46183574A US3914644A US 3914644 A US3914644 A US 3914644A US 461835 A US461835 A US 461835A US 46183574 A US46183574 A US 46183574A US 3914644 A US3914644 A US 3914644A
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Prior art keywords
cavity
vanes
tuning
array
anode
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Expired - Lifetime
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US461835A
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English (en)
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William A Gerard
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Varian Medical Systems Inc
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Varian Associates Inc
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Priority to US461835A priority Critical patent/US3914644A/en
Priority to DE2516103A priority patent/DE2516103C2/de
Priority to FR7511683A priority patent/FR2268351B1/fr
Priority to GB15421/75A priority patent/GB1505123A/en
Priority to JP4589175A priority patent/JPS5720660B2/ja
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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
    • H01J23/207—Tuning of single resonator

Definitions

  • ABSTRACT A coaxial magnetron of the type including a circular electric mode cavity coupled to a vane resonator system is tuned by means of a tuning structure movable in the circular electric mode cavity.
  • the tuning structure includes an array of electrically conductive reactive loading elements, such as vanes, reactively loading the resonator and an adjacent array of field perturbing elements. Relative motion is effected between the two arrays of elements to effect a cyclical variation or modulation of the reactive loading on the cavity and thus the output frequency of the tube.
  • electrically conductive reactive loading elements such as vanes
  • the present invention relates in general to frequency agile microwave tubes and more particularly to an improved rotary tuner for coaxial magnetrons.
  • the castellated cylindrical dielectric tuning structures were centrally disposed in the toroidal shaped coaxial circular electric mode cavity in the high field region thereof. With a substantial amount of dielectric material disposed permanently in the high field region of the circular electric mode cavity the dielectric material substantially resistively loads the cavity, thereby reducing its loaded Q'to an unacceptably low value.
  • the dielectric members serve to concentrate the electric field in the dielectric material such that when the rotating castellated rotor member is rotated out of registration withthe castellated stator inember,'arcing may tend to occur through the gap established between the two members. For these and other reasons the aforedescribed tuner has not proven satisfactory in practice.
  • this tuner arrangement has certain disadvantages which include instabilities in the output frequency, inability to obtain a tracking output signal for tuning a local oscillator or a receiver, due to such frequency irregularities, and the difficulty of fabricating the tuning structure due to its relatively small size and requirement that it operate within the vacuum envelope of the tube.
  • Still others have proposed schemes for tuning a coaxial magnetron wherein a circular array of rotatable ceramic paddles were Iocatedwithin the circular electric mode cavity.
  • The'paddles were driven in synchronism by a planetary gear arrangement. As each of the pad.- dles turned into a position of alignment with the electric field of the circular electric mode, the tube was tuned to its lowest frequency and conversely when the paddles were turned at right angles to the electric field vector the tube was tuned to its highest frequency.
  • the principal object of the present invention is the provision of an improved rotary tuner for coaxial magnetrons.
  • a cavity resonator as coupled to a microwave interaction structure for stabilizing the operating frequency thereof is tuned by effecting relative movementbetween a plurality of electrically conductive reactive loading elements coupled to the cavity for reactively loading same and an adjacent plurality of electromagnetic field perturbing elements, whereby the resonant frequency of the cavity resonator and thus the output frequency of the tube is modulated.
  • the cavity being tuned is a circular electric mode cavity of a magnetron which is coupled to the microwave interaction circuit comprising a vane resonator system.
  • the electrically conductive reactive loading elements are disposed along one of the walls of the cavity resonator being tuned.
  • the tuning structure includes a first array of electrically conductive reactive loading elements coupled to the fields of the resonator and a second array of dielectric field perturbing elements disposed adjacentv the array of loading elements for cyclically varying the reactive loading effect of the array of electrically conductive loading elements on the cavity being tuned in response to relative movement between the arrays of first and second tuning elements.
  • FIG. 1 is a longitudinal sectional view of a coaxial magnetron incorporating features of the present invention
  • FIG. 2 is an enlarged view of a portion of the structure of FIG. 1 delineated by line 2-2,
  • FIG. 3 is a sectional view of the structure of FIG. 2
  • FIG. 4 is a view similar to that of FIG. 3 depicting the dielectric tuning structure in a second position
  • FIG. 5 is a sectional view of the structure of FIG. 2
  • FIG. 6 is a fragmentary detail view of a portion of a structure similar to FIG. 2 and depicting an alternative embodiment of the present invention.
  • FIG. 7 is a sectional view of the structure of FIG. 6 taken along line 7-7 in the direction of the arrows.
  • DESCRIPTION OF THE PREFERRED EMBODIMENTS for emitting a stream of electrons in an annular interaction region defined between the cathode and surrounding cylindrical anode 13 including a circular array of anode vanes 14 projecting inwardly from the cylindrical anode 13 toward the centrally disposed cathode 12 for defining a microwave intereaction circuit.
  • a circular array of elongated slots 15 is provided in the cylindrical wall of the anode 13 for providing wave energy communication with alternate vane resonators defined by the region between adjacent vanes 14.
  • a toroidal shaped cavity resonator 16 is disposed surrounding the anode 13 in electromagnetic field exchanging relation with the vane resonators via the intermediary of the coupling slots 15. Since only alter nate vane resonators are directly coupled to the toroidal cavity 16, the 11' mode of oscillation of the vane resonator system excites the TE circular electric mode of the toroidal resonator 16.
  • a cylindrical wave permeable vacuum envelope 17 is disposed surrounding the cylindrical anode 13 such that the electron interaction region between the cathode 12 and the anode resonators 14 may be evacuated by evacuation of the envelope 17 while allowing the external resonator 16 to operate at atmospheric pressure or to be pressurized with a suitable electrically insulative gas, such as SF
  • a pair of cylindrical permanent magnet structures 18 are disposed within the anode 13 in coaxially spaced relation from the cathode and on opposite sides of the interaction gap between the cathode 12 and the surrounding vane resonators 14.
  • the permanent magnets 18 are polarized to produce an axially directed magnetic field through the annular interaction region defined between the tips of the vane resonators l4 and the cathode emitter 12.
  • the toroidal cavity resonator 16 is defined by the region of space bounded by the outside of the cylindrical anode wall 13 and the inside of a cylindrical coaxially disposed radially spaced wall 19.
  • the top and bottom end walls of the resonator 16 are defined by annular electrically conductive plates 21 and 22 joined to the outer side wall 19 and to the vacuum envelope 17.
  • a tuning structure 23 for effecting frequency modulation of the output frequency of the tube. More specifically, an array of radially directed electrically conductive lands or vanes 24 are formed in the inside surface of the upper wall 21 of the resonator 16 to define an array of reactive loading elements coupled to the electromagnetic fields of the excited TE mode of the resonator 16 for reactively loading the resonator 16.
  • a second rotary tuning member 25 is formed by an annular dielectric plate 26, as of low loss ceramic such as alumina, beryllia, sapphire, etc.
  • the annular dielectric plate 26 includes an array of apertures 27 with the web portion of the plate which remains between adjacent apertures 27 defining a circular array of field perturbing elements 28.
  • the circumferential extent of the apertures 27 is the same as the circumferential extent of the space (groove) between adjacent vanes 24 such that when the angular position of the rotatable tuning member 25 is in the position as shown in FIG. 3 the inductive reactive loading effect of the reactive loading elements 24 is a minimum and therefore the output frequency of the tube is at its highest frequency.
  • the reactive loading effect of the elements 24 is a maximum on the operating frequency of the cavity 16 such that this relative position corresponds to the lowest frequency of the cavity.
  • a circular array of axially directed dielectric tab portions 29 of the dielectric tuning member 25 are fixed, as by brazing, to the lower end of a cylindrical conductive actuator 31 which passes through an annular slot in the upper wall 21 of the resonator 16.
  • the cylindrical actuator 31 is afiixed to an axle 32 (see FIG. 1) which is rotatably supported from a cup-shaped housing 33 via the intermediary of bearing assembly 34.
  • This time varying signal is employed for tuning the receiver of aradar or the like to the operating frequency of the tube 11 for improved signal-to-noise ratio.
  • Output microwave energy is extracted from the coaxial resonator 16 via a conventional output coupling iris 37 and waveguide 38 for propagation to a suitable load such as an antenna, not shown. If there are N number of vanes 24 and N number of field perturbing members 28, the output frequency of the tube will be swept across its tunable band 2N times per revolution of the rotary tuning member 25.
  • the generator 36 preferably has the same number of poles as there are reactive loading elements 24.
  • FIGS. 6 and 7 there is shown an alternative embodiment of the present invention.
  • This embodiment is similar to that of FIGS. l-5 with the exception that the rotating tuning member 25 comprises a slotted dielectric cylinder 26 provided with anarray of apertures 27 (slots), the apertures corresponding to the grooves or spaces defined between longitudinally directed lands or vanes 24' provided in the inside surface of the outer side wall 19 of the cavity 16.
  • the circular array of longitudinally directed vanes 24' serves as an array of reactive loading elements for inductively reactively loading the cavity 16.
  • the web portion 28, defined between the adjacent apertures 27', of the cylindrical dielectric member 26' serves as an array of field perturbing elements, in the manner as previously described with regard to FIGS. 3 and 4, for modulating the reactive loading of the cavity 16 in accordance with the relative position of the field perturbing portions 28 relative to the lands or vanes 24.
  • the cylindrical tuning member 25' is affixed to the metallic cylindrical actuator 31 which in-tum is rotated via the axle 32, in the manner as described with regard to FIG. 1.
  • the reactive loading members may be disposed along the top wall 21 or along the side wall 19 or, if desired, may be disposed along the bottom wall 22. Furthermore, such reactive loading members 24 and 24 may be located along both the top and bottom walls 21 and 22 as well as along the side wall 19 for effecting greater tuning range.
  • the rotary tuner 25 is utilized in a coaxial magnetron of the type wherein the stabilizing cavity 16 surrounds the array of coupled vane resonators 14. While this is a preferred embodiment, an alternative embodiment is of the type wherein the vane resonator system 14 surrounds a central circular electric mode resonator.
  • a tube of this latter type is disclosed and claimed in U.S. Pat. No. 3,231,781 issued Jan. 25, 1966 and assigned to the same assignee as the present invention.
  • the top wall of the central resonator could include the array of radially directed vanes 24 and the rotatable dielectric plate 25 would include an array of radially directed apertures to define the array of perturbing members 28.
  • a tube incorporating the tuner of the present invention provides means for rapidly dithering or sweeping the output frequency of the tube to and fro over a certain band of frequencies.
  • An advantage to the tuner of the present invention is that the dielectric tuning structure 25 is not located in a region of intense electric field and furthermore the amount of dielectric is substantially less than that previously proposed in the aforecited U.S. Pat. No. 3,412,285, because the field is concentrated by the conductive loading elements whereby the loaded Q of the cavity is not reduced below a useable value.
  • the tuner of the present invention employs a much larger number of teeth in the relatively rotatable tuning structures such that the rate at which the rotating tuning member must be turned to achieve a certain modulation frequency is substantially reduced compared with the tuner proposed in the aforecited U.S. Pat. No. 3,412,285. Reducing the speed of the tuner increases bearing life and thus operating life of the tube or, if operated at the same speed, produces a much higher rate of frequency modulation of the output frequency of the tube.
  • microwave circuit means in energy exchanging relation with said stream of electrons for generating electromagnetic energy
  • cavity resonator means coupled to said circuit means for exciting in said cavity a resonance mode affecting the frequency of said electromagnetic energy
  • tuner means within said cavity for cyclically varying the resonant frequency of said mode of said cavity, said tuner means comprising a conductive reactive loading structure, a field perturbing structure, and an axis;
  • said conductive reactive loading structure comprising an array of vanes disposed on a circle about said axis and aligned along radii of said circle such that electric fields of said mode excite electric fields between adjacent vanes whereby said resonance mode is reactively loaded by said vanes;
  • said field perturbing structure comprising an array of dielectric elements disposed on a circle about said axis and further disposed to intercept fringing portions of said electric fields between adjacent vanes and,
  • said cavity resonator means includes a chamber which is generally a figure of revolution about a cavity axis.
  • said chamber is toroidal shaped having a pair of axially spaced coaxially disposed annular conductive end walls and a pair of radially spaced coaxially disposed axially coextensive cylindrical side walls, and wherein said array of vanes is disposed along at least one of said end walls and side walls of said cavity resonator means.
  • said chamber is generally cylindrical and has a pair of axially spaced end walls and a cylindrical side wall and wherein said array of vanes is disposed along at least one of said end and side walls.
  • a coaxial magnetron comprising a cylindrical cathode, a cylindrical anode surrounding said cathode and coaxial therewith, an array of anode vanes extending radially inward from said anode wall and defining a plurality of anode resonators, an outer coaxial cavity resonator surrounding said anode wall, coupling slots provided in said anode for coupling energy from said anode resonator to said outer coaxial cavity resonator, tuning means provided within said outer coaxial cavity resonator, said tuning means comprising a first tuning member and a second tuning member, and means for providing relative rotational motion of said first and second tuning members to modify the electric field within said cavity resonator and thereby vary the frequency of said coaxial magnetron, and wherein said first of said tuning members comprises an electrically conductive structure having a plurality of electrically conductive vanes disposed on a circle and aligned with radii of said circle for reactively loading said coaxial cavity resonator, and wherein said

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US461835A 1974-04-18 1974-04-18 Rotary tuner for circular electric mode crossed field tube Expired - Lifetime US3914644A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US461835A US3914644A (en) 1974-04-18 1974-04-18 Rotary tuner for circular electric mode crossed field tube
DE2516103A DE2516103C2 (de) 1974-04-18 1975-04-12 Laufzeitröhre
FR7511683A FR2268351B1 (US07223432-20070529-C00017.png) 1974-04-18 1975-04-15
GB15421/75A GB1505123A (en) 1974-04-18 1975-04-15 Rotary tuner for circular electric mode crossed field tub
JP4589175A JPS5720660B2 (US07223432-20070529-C00017.png) 1974-04-18 1975-04-17

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US461835A US3914644A (en) 1974-04-18 1974-04-18 Rotary tuner for circular electric mode crossed field tube

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US3914644A true US3914644A (en) 1975-10-21

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JP (1) JPS5720660B2 (US07223432-20070529-C00017.png)
DE (1) DE2516103C2 (US07223432-20070529-C00017.png)
FR (1) FR2268351B1 (US07223432-20070529-C00017.png)
GB (1) GB1505123A (US07223432-20070529-C00017.png)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3987333A (en) * 1974-07-24 1976-10-19 Hitachi, Ltd. Magnetron comprising a radially magnetized permanent magnet and an axially magnetized permanent magnet
US4143300A (en) * 1976-09-16 1979-03-06 E M I-Varian Limited Spin tuned magnetrons
US20110241543A1 (en) * 2010-03-31 2011-10-06 E2V Technologies (Uk) Limited Magnetron
CN102595764A (zh) * 2012-03-13 2012-07-18 苏州爱因智能设备有限公司 用于电子直线加速器的自动频率控制驱动装置
US20140210340A1 (en) * 2012-09-13 2014-07-31 E2V Technologies (Uk) Limited Magnetron cathodes
CN107946157A (zh) * 2017-12-31 2018-04-20 中国电子科技集团公司第十二研究所 一种同轴磁控管的微波频率微调装置及同轴磁控管

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57136738A (en) * 1981-02-17 1982-08-23 Nec Corp Microwave tube of frequency sweeping type
TW201141316A (en) * 2010-05-04 2011-11-16 Ind Tech Res Inst A linear-type microwave plasma source using rectangular waveguide with a biased slot as the plasma reactor

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2449794A (en) * 1944-10-12 1948-09-21 Westinghouse Electric Corp Electron discharge device
US3333148A (en) * 1966-12-12 1967-07-25 Westinghouse Electric Corp Ferrite tuned coaxial magnetron
US3412285A (en) * 1965-10-20 1968-11-19 Westinghouse Electric Corp Coaxial magnetron with rotatable tuning means
US3435284A (en) * 1965-12-28 1969-03-25 Rayethon Co Turnable coaxial cavity magnetron
US3441796A (en) * 1965-08-09 1969-04-29 English Electric Valve Co Ltd Magnetrons having cyclically varying frequencies
US3471744A (en) * 1967-09-01 1969-10-07 Varian Associates Coaxial magnetron having a segmented ring slot mode absorber
US3590312A (en) * 1969-04-16 1971-06-29 Litton Precision Prod Inc Tunable coaxial magnetron
US3731137A (en) * 1972-02-03 1973-05-01 Raytheon Co Coaxial magnetron

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4425768Y1 (US07223432-20070529-C00017.png) * 1964-07-01 1969-10-29

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2449794A (en) * 1944-10-12 1948-09-21 Westinghouse Electric Corp Electron discharge device
US3441796A (en) * 1965-08-09 1969-04-29 English Electric Valve Co Ltd Magnetrons having cyclically varying frequencies
US3412285A (en) * 1965-10-20 1968-11-19 Westinghouse Electric Corp Coaxial magnetron with rotatable tuning means
US3435284A (en) * 1965-12-28 1969-03-25 Rayethon Co Turnable coaxial cavity magnetron
US3333148A (en) * 1966-12-12 1967-07-25 Westinghouse Electric Corp Ferrite tuned coaxial magnetron
US3471744A (en) * 1967-09-01 1969-10-07 Varian Associates Coaxial magnetron having a segmented ring slot mode absorber
US3590312A (en) * 1969-04-16 1971-06-29 Litton Precision Prod Inc Tunable coaxial magnetron
US3731137A (en) * 1972-02-03 1973-05-01 Raytheon Co Coaxial magnetron

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3987333A (en) * 1974-07-24 1976-10-19 Hitachi, Ltd. Magnetron comprising a radially magnetized permanent magnet and an axially magnetized permanent magnet
US4143300A (en) * 1976-09-16 1979-03-06 E M I-Varian Limited Spin tuned magnetrons
US20110241543A1 (en) * 2010-03-31 2011-10-06 E2V Technologies (Uk) Limited Magnetron
US8659227B2 (en) * 2010-03-31 2014-02-25 E2V Technologies (Uk) Limited Magnetron
CN102595764A (zh) * 2012-03-13 2012-07-18 苏州爱因智能设备有限公司 用于电子直线加速器的自动频率控制驱动装置
US20140210340A1 (en) * 2012-09-13 2014-07-31 E2V Technologies (Uk) Limited Magnetron cathodes
US9177749B2 (en) * 2012-09-13 2015-11-03 E2V Technologies (Uk) Limited Magnetron cathodes
CN107946157A (zh) * 2017-12-31 2018-04-20 中国电子科技集团公司第十二研究所 一种同轴磁控管的微波频率微调装置及同轴磁控管

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Publication number Publication date
FR2268351A1 (US07223432-20070529-C00017.png) 1975-11-14
JPS5198948A (US07223432-20070529-C00017.png) 1976-08-31
DE2516103C2 (de) 1985-05-23
FR2268351B1 (US07223432-20070529-C00017.png) 1981-05-29
DE2516103A1 (de) 1975-10-30
GB1505123A (en) 1978-03-22
JPS5720660B2 (US07223432-20070529-C00017.png) 1982-04-30

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