US3787747A - Periodic magnetically focused beam tube - Google Patents

Periodic magnetically focused beam tube Download PDF

Info

Publication number
US3787747A
US3787747A US00278408A US3787747DA US3787747A US 3787747 A US3787747 A US 3787747A US 00278408 A US00278408 A US 00278408A US 3787747D A US3787747D A US 3787747DA US 3787747 A US3787747 A US 3787747A
Authority
US
United States
Prior art keywords
slab
disposed
major face
sheet
magnetizable
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
US00278408A
Other languages
English (en)
Inventor
A Scott
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.)
Varian Medical Systems Inc
Original Assignee
Varian Associates Inc
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 Varian Associates Inc filed Critical Varian Associates Inc
Application granted granted Critical
Publication of US3787747A publication Critical patent/US3787747A/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
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/18—Tubes with a single discharge path having magnetic control means; having both magnetic and electrostatic control means
    • 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
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/08—Focusing arrangements, e.g. for concentrating stream of electrons, for preventing spreading of stream
    • H01J23/087—Magnetic focusing arrangements
    • H01J23/0873—Magnetic focusing arrangements with at least one axial-field reversal along the interaction space, e.g. P.P.M. focusing

Definitions

  • the periodic magnet structure for a periodically focused beam tube is formed by a single pair of homogeneous slabs of magnetizable material that are permanently magnetized with a pattern of magnetic poles of alternating polarity taken along the direction of the beam path.
  • a pair of ceramic slabs are disposed to straddle the sheet beam and the internal planar faces of the ceramic slabs have circuits printed thereon for: electrical connections to all elements, beam forming electrodes, microwave interaction structure, edge focusing electrodes, and the beam collector electrode structure.
  • the permanently magnetized slabs are disposed external to the vacuum envelope, straddling the printed circuit ceramic slabs, for focusing the beam.
  • the present invention relates to the field of periodic permanent magnet focused microwave beam tubes such as traveling wave tubes and klystrons.
  • tubular or sheet electron beams may be magnetically focused by means of a periodic magnetic focusing structure having a pole pattern which is characterized by poles of alternating polarity taken in the direction of the beam path.
  • periodic magnetic focusing structures two types of geometries have been employed; one of which employs magnetic poles of the same polarity disposed in registration transversely across the beam and the second geometry wherein poles of opposite polarity are disposed in transverse registration across the beam path.
  • the magnetic focusing structure of the first type having poles of the same polarity disposed transversely of the beam path is disclosed in U. S. Pat. No. 3,102,211 (see FIG. 13) issued Aug. 27, 1963.
  • the second type of geometry wherein the poles are of opposite polarity taken transversely of the beam path is disclosed and claimed in U. S. Pat. No. 3,013,173 issued Dec. l2, 1961.
  • the magnet structure has been relatively complicated because it requires a plurality of permanently magnetized magnets separated by magnetically permeable material or spacers of a different magnetic property.
  • the resultant structure is relatively complicated requiring a relatively large number of parts which must be assembled around the envelope of the tube to provide a composite periodic permanent magnet beam focusing structure.
  • the principal object of the present invention is the provision of an improved periodic magnetically focusedbeam tube.
  • the periodic magnetic focusing structure comprises a structure of generally homogeneous permanently magnetizable material magnetized in a pattern of periodic permanent poles of alternating polarity taken in a direction along the beam path, whereby a relatively complicated periodic permanent pole geometry is obtained with an extremely simple magnetic structure.
  • a microwave beam tube includes a microwave interaction structure formed on a major face of a dielectric slab facing the electron beam and a permanently magnetized pair of slabs of generally homogeneous magnetic material forms the beam focusing structure disposed external of the vacuum envelope of the tube adjacent the outside wall of the dielectric slab for causing the magnetic fields to permeate the dielectric slab and microwave interaction structure to focus the beam internally of the vacuum envelope of the tube.
  • a microwave interaction structure, electrostatic beam edge focusing electrodes, electrical connections, beam forming electrode structure, and beam collector electrode structure are all formed, as by printing, on the common face of a dielectric slab facing a sheet-shaped electron beam.
  • a pair of slabs of homogeneous permanently magnetizable material is disposed overlaying the dielectric slab externally of the vacuum envelope.
  • the magnet structure is permanently magnetized in a pattern of periodic permanent poles of alternating polarity taken in a direction along the beam path, whereby an extremely simplified tube structure is obtained.
  • a thermionic cathode is disposed intermediate the ends of two printed microwave interaction structures carried from the same face of a dielectric slab for projecting electron beams in opposite directions over the printed circuits to provide two microwave tubes within a common envelope.
  • plural microwave tubes are provided within a single envelope by printing a plurality of interaction circuits in side-byside relation on a common dielectric slab and projecting a stream of electrons over the printed circuits to obtain-a plurality of microwave tubes within a common envelope.
  • the permanently magnetized homogeneous slab of magnet material is flexible such that after a pattern of poles has been charged into the slab it is deformed, such as into a cylinder, to match the contour of the envelope of the beam to be focused.
  • FIG. 1 is an exploded schematic perspective view of a microwave tube incorporating features of the present invention
  • FIG. 1A is an enlarged detail view of an alternative edge seal embodiment for a portion of the structure of FIG. 1 delineated by line lA-IA,
  • FIG. 2A is a perspective schematic view of a periodic magnetic focusing pole structure useful in the tube of FIG. 1,
  • FIG. 2B is a perspective plot of the axial magnetic field intensity for the structure of FIG. 2A
  • FIG. 3A is a view similar to that of-FIG. 2 depicting an alternative embodiment of the magnetic focusing structure for the tube of FIG. 1, I
  • FIG. 3B is a perspective plot of the transverse magnetic field intensity for the structure of FIG. 3A.
  • FIG. 4 is a schematic cross-sectional view of a sheet electron beam depicting the space charge focusing forces
  • FIG. Si is a plot of transverse and lateral electric defocusing field forces versus transverse extent of the electron beam of FIG. 4,
  • FIG. 6 is an enlarged cross-sectional view of a beam edge portion of the tube structure of FIG. 1 depicting the beam edge electrostatic focusing electrode structrue and its edge focusing electric field,
  • FIG. 7 is a plot of collector current in milliamps versus voltage on the electrostatic beam edge focusing electrode structure,-
  • FIG. 8 is a view similar to that of FIG. 1 depicting an alternative tube structure of the present invention.
  • FIG. 9 is a schematic plan view of a combination oscillator and amplifier printed circuit tube incorporating features of the present invention.
  • a tube 11 includes a pair of ceramic slabs l2 and 13, as of alumina or beryllia ceramic, sealed together in a gas-tight manner in spaced apart relation via the intermediary of a suitable gastight spacing structure such as spacing ring 14 as of metal or ceramic.
  • the ceramic slabs l2 and 13 are sealed at their peripheries, as by brazing, to metallic sealing frames 15 and 16 which in turn are sealed together as by heliarc welding at 20.
  • the frames 15 and 16 replace spacer l4 and serve as a means for sealing the vacuum envelope of the tube.
  • a thermionic cathode emitter 17 is mounted to one of the ceramic plates 12 and 13, such as the lower plate 12, by soldering the heater leads of the thermionic cathode 17 to metalized leads 10 formed on the inner face of the lower ceramic plate 12.
  • the thermionic cathode assembly 17 is preferably disposed at one end of the ceramic tube 11 in the space between the spaced ceramic plates 12 and 13 respectively.
  • a microwave interaction structure 18, such as a meanderline, an interdigital line, a double meanderline, or an array of distributed interaction klystron cavities or the like is formed on each of the opposed inner faces of the ceramic plates 12 and 13, respectively, and a beam collector electrode plate 119 is similarly formed on both of the lower and upper ceramic plates 12 and 13.
  • a pair of beam edge electrostatic beam focusing electrodes 21 are disposed at the side of each of the microwave interaction structures 18 on both the opposed inner surfaces of the lower and upper ceramic plates 12 and 13, respectively.
  • a pair of sheet-shaped magnets 23 and 24 are disposed externally of the vacuum envelope abutting the outside faces of the lower and upper dielectric ceramic slabs l2 and 13, respectively.
  • the sheet-shaped magnets 23 and 24 are made of a generally homogeneous permanently magnetizable magnetic material, such as ferromagnetic material, or permanently magnetizable particles embedded in a suitable binder such as silicon rubber.
  • Suitable magnet materials include barium ferrite Ba Fm- 0 preferably oriented, and barium ferrite embedded in silicon rubber. Such materials preferably have a high coercive force, as of 5 2,000 Oresteds.
  • the sheet-shaped magnets 23 and 24 are permanently magnetized in a pattern generally indicated with respect to magnet 24, such pattern having a plurality of laterally directed magnetic poles of alternating polarity taken in a direction along the beam path as shown schematically in FIGS. 2 and 3.
  • the permanent magnet pattern is readily charged into the slab-shaped magnet 24 by placing the magnetic sheet 24 over a suitable magnetizing fixture consisting of a generally comb-shaped magnetically permeable material, as of soft iron.
  • the teeth of the comb have a vane shape generally conforming to the shape of the laterally directed poles to be charged into the magnetic sheet 24.
  • Energizing coils are wound about the base of the individual vane-shaped teeth of the combshaped charging fixture with the direction of current through adjacent coils being in the opposite direction such as to generate, when energized with current, poles of alternating polarity taken in the direction down the spine of the comb-shaped charging fixture.
  • the magnetic fixture 24, which is to be charged, can be disposed between the mutually opposed teeth of two such comb-shaped charging fixtures with the transversely aligned opposed teeth of the combs being of opposite magnetic polarity such that the magnetic sheet 24 is charged uniformly through the sheet with poles of alternating polarity.
  • the sheet 24 may be disposed over a single charging comb and charged.
  • the magnetic sheet 24 is permanently magnetized with transverse directed poles opposite the ends of each of the vane-shaped teeth of the charging fixture and with longitudinal polarization in the outer regions of the fringing field between adjacent poles.
  • An advantage to making the magnet structure 23 and 24 by charging the desired pole pattern is that, once a charging fixture has been made the desired magnet structure can be duplicated exactly without assembly and fabrication of individual magnets and spacers. Also, the intensity and period of the periodic magnet structure is readily varied down the length of the magnet structure by varying the ampere turns around the individual vane-shaped teeth of the charging fixture and by varying the spacing between adjacent teeth of the charging fixture.
  • the slow wave circuit 18 has a lateral width of approximately 0.80 inches and an axial length of approximately 5 inches.
  • the electron beam has a lateral width of approximately 0.700 inches and a thickness of approximately 0.055 inches.
  • Slow wave circuits 18 are formed as by printed circuit techniques on the inner major faces of the opposed ceramic sheets 12 and 13, each slab having a thickness of approximately 0.100 inches and being spaced apart from the opposed slab by approximately 0.120 inches.
  • the electrostatic beam edge focusing electrodes 21 are spaced by approximately 0.060 inches from the adjacent edge of the slow wave circuit 18 and each electrode 21 has a lateral width of approximately 0.050 inches.
  • the sheet-shaped magnets 23 and 24 each have a lateral width of approximately 1.00 inches and a thickness of approximately 0.100 inches and extend for substantially the entire axial length of the tube.
  • the magnet structure had a period of 0.5 inch from one north pole to the succeeding north pole taken along the beam path.
  • the periodic beam focusing field had a peak longitudinal component of magnetic field intensity in the midplane of the beam of 200 gauss.
  • a magnetically permeable member such as a sheet of soft iron, not shown, is preferably disposed over the outer major face of the sheet-shaped magnets 23 and 24 to serve as a return magnetic flux path of high magnetic permeability.
  • FIGS. 4-6 the effect of the beam edge electrostatic focusing electrodes 21 is shown.
  • the sheet-shaped electron beam is shown at 27 with electrostatic space charge defocusing forces as indicated by the arrows radiating away from the beam 27. From the direction of the arrows, it is seen that the defocusing forces are substantially transverse in the midlateral sections of the beam 27 but, near the beam edges, the defocusing forces become substantially lateral.
  • FIG. 5 there is shown the relative amplitude of the transverse and lateral spacecharged defocusing electric fields. From the curve it is shown that the transverse defocusing electric field falls off as the lateral defocusing field increases.
  • the beam 27 will have a certain beam voltage, as of +900 volts relative to the cathode potential.
  • the beam voltage is at ground potential which is also the potential on the slow wave circuit 18 and the cathode 17 is run at a negative potential.
  • the difference between the slow wave circuit potential and the cathode potential corresponds to the beam voltage.
  • the beam edge focusing electrodes 21 are operated at a potential negative with respect to the beam potential and potential of the circuit 18.
  • the electrostatic force on the electrons is indicated by arrows 28 and it is seen that these arrows, in the mid-transverse plane of the beam at the edge of the beam, have a maximum amplitude tending to force the electrons back toward the mid-lateral plane of the beam 27.
  • the potential on the edge focusing electrodes 21 relative to the beam potential and the potential on the circuit 18 is not critical. This is shown in FIG. 7 wherein collector currents in milliamps is plotted versus voltage on the edge focus electrodes 21. From the curve it is seen that once a minimum voltage has been established between the electrostatic focus electrode and the beam voltage and circuit potential, as of 50 volts, that a further increase of the voltage difference has very little effect on beam transmission. It is also seen that a relatively high beam transmission efficiency is obtained, as of 95 percent.
  • FIG. 8 there is shown an alternative microwave tube embodiment 30 of the present invention.
  • the tube 30 is substantially the same as that previously described with regard to FIG. 1 with the exception that the longitudinal and lateral extent of the ceramic plates 12 and 13 has been extended to accommodate a plurality of parallel microwave interaction circuits l8 and formed on both of the mutually opposed faces of the ceramic plates 12 and 13, respectively.
  • the thermionic cathode emitter assembly 17 has been moved to the center of the tube and the collector electrodes 19 are disposed at opposite ends of the ceramic slabs 12 and 13 such that the electron beams are directed from both sides of the thermionic cathode emitter 17 toward opposite ends of the individual microwave interaction circuits 18 to the collector assemblies 19 at opposite ends of the tube.
  • a single cathode emitter 17 can serve to provide an electron beam for a plurality of individual tubes connected in parallel.
  • the microwave circuits and the connections for the individual tubes are readily formed by printed circuit techniques such that the fabrication cost for the 10 tubes is substantially the same as it would be for one tube.
  • The'RF outputs of the individual circuits 18 are taken out through suitable RF output connectors 3]. arrayed at opposite ends of the composite tube 30.
  • the individual RF outputs may be used individually or connected in parallel for increasing the power output capability of the tube 30.
  • the thermionic cathode 17 may comprise, for example, a directly heated thoriated tungsten ribbon.
  • the microwave circuit 18 includes two circuit portions, circuit portion 18 is a forward wave amplifier circuit, and circuit portion 18 is an interdigital backward wave oscillator circuit.
  • the output of the backward wave oscillator circuit 18 is fed into the input of the forward wave slow wave circuit via printed circuit line 33 disposed at the upstream end of the electron beam.
  • the beam is emitted by a thermionic emitter 17 such that the sheet beam is common to both slow wave circuits l8 and 18' and is collected by a common collector electrode 19.
  • the magnet may comprise a hollow cylinder which is charged with a pattern of axially spaced ring-shaped pole regions of alternating magnetic polarity taken in the axial direction along the beam path.
  • two such concentrically disposed cylindrical magnets may" be employed for focusing the annular beam passable coaxially of and between the pair of cylindrical permanently magnetized magnet structures.
  • said beam forming means forms a sheet-shaped beam
  • said homogeneous structure includes, a generally homagnetizable member being permanently magnetized in a pattern having periodic permanent poles of alternating polarity taken in a direction along the beam path.
  • said magnetizable structure comprises a slab of substantially homogeneous permanently magnetizable material having a planar face facing said beam.
  • said magnet slab is a slab of ferrite magnet material.
  • said magnet slab is a slab of permanently magnetizable magnet particles embedded in a binder material.
  • said permanently magnetizable structure includes a pair of said magnetizable slabs disposed on opposite sides of said sheet-shaped beam with their respective major faces disposed facing a corresponding major face of said sheet-shaped beam.
  • the apparatus of claim 11 including, electrostatic edge focusing electrode means disposed adjacent the edge regions of said slow wave circuit in electrical insulative relation thereto and extending along the opposte edges of said sheet-shaped beam for constraining lateral expansion of said sheet-shaped beam.
  • the apparatus of claim 15 including beam collector electrode means disposed on and lying substantially entirely on said planar major face of said dielectric slab at the terminal end of said beam path.
  • the apparatus of claim 16 including, beam focus electrode structure disposed on and lying substantially entirely on said planar major face of said dielectirc slab at the upstream end of said beam path intermediate said cathode emitter means and said slow wave circuit means.
  • said electrical circuit means includes a pair of elongated microwave interaction structure means disposed of said major face of said dielectirc slab in end-to-end relation, and wherein said beam forming and projecting means includes a thermionic cathode emitter disposed intermediate the adjacent ends of said pair of microwave interaction structure means for projecting a pair of electron beams in opposite direction along said pair of microwave interaction structure means.
  • said electrical circuit means includes a plurality of elongated microwave interaction structure means disposed on and lying substantially entirely on said major face of said dielectric slab in side-by-side relation.

Landscapes

  • Microwave Tubes (AREA)
US00278408A 1972-08-07 1972-08-07 Periodic magnetically focused beam tube Expired - Lifetime US3787747A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US27840872A 1972-08-07 1972-08-07

Publications (1)

Publication Number Publication Date
US3787747A true US3787747A (en) 1974-01-22

Family

ID=23064862

Family Applications (1)

Application Number Title Priority Date Filing Date
US00278408A Expired - Lifetime US3787747A (en) 1972-08-07 1972-08-07 Periodic magnetically focused beam tube

Country Status (7)

Country Link
US (1) US3787747A (fr)
JP (1) JPS49124962A (fr)
DE (1) DE2338061A1 (fr)
FR (1) FR2195838B1 (fr)
GB (1) GB1406938A (fr)
IL (1) IL42696A (fr)
IT (1) IT992766B (fr)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909651A (en) * 1974-08-15 1975-09-30 Us Army Low-cost periodic permanent magnet and electrostatic focusing scheme for electron tubes
US3971965A (en) * 1975-03-31 1976-07-27 The United States Of America As Represented By The Secretary Of The Army Internally-focused traveling wave tube
US3982152A (en) * 1974-11-25 1976-09-21 Raytheon Company Cascade crossed field device
US4107573A (en) * 1977-02-02 1978-08-15 The United States Of America As Represented By The Secretary Of The Army Printed circuit traveling wave tube
US4232249A (en) * 1978-09-28 1980-11-04 Bell Telephone Laboratories, Incorporated Beam-switched traveling wave tube
US4392078A (en) * 1980-12-10 1983-07-05 General Electric Company Electron discharge device with a spatially periodic focused beam
US5227691A (en) * 1989-05-24 1993-07-13 Matsushita Electric Industrial Co., Ltd. Flat tube display apparatus
US5712537A (en) * 1993-01-11 1998-01-27 Real Time Electronics, Corporation High frequency scan converter
US6700454B2 (en) 2001-06-29 2004-03-02 Zvi Yaniv Integrated RF array using carbon nanotube cathodes
US20040251652A1 (en) * 2003-06-10 2004-12-16 Hutchinson Method of fabricating a magnetic coder device, and the device obtained thereby
US20050062424A1 (en) * 2003-06-30 2005-03-24 Chiping Chen Photonic crystal ribbon-beam traveling wave amplifier
WO2005017938A3 (fr) * 2003-08-12 2005-05-26 Genvac Aerospace Corp Procede et appareil pour oscillateur a ondes regressives biplanaire
US7193485B2 (en) 2003-08-12 2007-03-20 James A. Dayton, Jr. Method and apparatus for bi-planar backward wave oscillator
WO2008008504A2 (fr) * 2006-07-13 2008-01-17 Manhattan Technologies, Llc Appareil et procédé pour produire des oscillations électromagnétiques
US20100045160A1 (en) * 2008-08-20 2010-02-25 Manhattan Technologies Ltd. Multibeam doubly convergent electron gun
US8723137B1 (en) * 2012-10-17 2014-05-13 Innosys, Inc Hybrid magnet for vacuum electronic device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2812470A (en) * 1954-10-22 1957-11-05 Bell Telephone Labor Inc Periodic focusing in traveling wave tubes
US2911555A (en) * 1957-09-04 1959-11-03 Hughes Aircraft Co Traveling-wave tube
US3231780A (en) * 1960-10-14 1966-01-25 Sfd Lab Inc Meandering slow wave circuit having high impedance stub support means
US3504222A (en) * 1966-10-07 1970-03-31 Hitachi Ltd Slow-wave circuit including meander line and shielding therefor
US3610999A (en) * 1970-02-05 1971-10-05 Varian Associates Slow wave circuit and method of fabricating same
US3670196A (en) * 1971-02-24 1972-06-13 Raytheon Co Helix delay line for traveling wave devices
US3705327A (en) * 1971-06-02 1972-12-05 Allan W Scott Microwave generator with interleaved focusing and interaction structures

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3102211A (en) * 1959-08-19 1963-08-27 Varian Associates Adiabatic beam condenser method and apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2812470A (en) * 1954-10-22 1957-11-05 Bell Telephone Labor Inc Periodic focusing in traveling wave tubes
US2911555A (en) * 1957-09-04 1959-11-03 Hughes Aircraft Co Traveling-wave tube
US3231780A (en) * 1960-10-14 1966-01-25 Sfd Lab Inc Meandering slow wave circuit having high impedance stub support means
US3504222A (en) * 1966-10-07 1970-03-31 Hitachi Ltd Slow-wave circuit including meander line and shielding therefor
US3610999A (en) * 1970-02-05 1971-10-05 Varian Associates Slow wave circuit and method of fabricating same
US3670196A (en) * 1971-02-24 1972-06-13 Raytheon Co Helix delay line for traveling wave devices
US3705327A (en) * 1971-06-02 1972-12-05 Allan W Scott Microwave generator with interleaved focusing and interaction structures

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3909651A (en) * 1974-08-15 1975-09-30 Us Army Low-cost periodic permanent magnet and electrostatic focusing scheme for electron tubes
US3982152A (en) * 1974-11-25 1976-09-21 Raytheon Company Cascade crossed field device
US3971965A (en) * 1975-03-31 1976-07-27 The United States Of America As Represented By The Secretary Of The Army Internally-focused traveling wave tube
US4107573A (en) * 1977-02-02 1978-08-15 The United States Of America As Represented By The Secretary Of The Army Printed circuit traveling wave tube
US4232249A (en) * 1978-09-28 1980-11-04 Bell Telephone Laboratories, Incorporated Beam-switched traveling wave tube
US4392078A (en) * 1980-12-10 1983-07-05 General Electric Company Electron discharge device with a spatially periodic focused beam
US5227691A (en) * 1989-05-24 1993-07-13 Matsushita Electric Industrial Co., Ltd. Flat tube display apparatus
US5712537A (en) * 1993-01-11 1998-01-27 Real Time Electronics, Corporation High frequency scan converter
US6700454B2 (en) 2001-06-29 2004-03-02 Zvi Yaniv Integrated RF array using carbon nanotube cathodes
US7452492B2 (en) * 2003-06-10 2008-11-18 Hutchinson Method of fabricating a magnetic coder device, and the device obtained thereby
US20040251652A1 (en) * 2003-06-10 2004-12-16 Hutchinson Method of fabricating a magnetic coder device, and the device obtained thereby
US20050062424A1 (en) * 2003-06-30 2005-03-24 Chiping Chen Photonic crystal ribbon-beam traveling wave amplifier
US7538608B2 (en) 2003-06-30 2009-05-26 Massachusetts Institute Of Technology Photonic crystal ribbon-beam traveling wave amplifier
US7193485B2 (en) 2003-08-12 2007-03-20 James A. Dayton, Jr. Method and apparatus for bi-planar backward wave oscillator
WO2005017938A3 (fr) * 2003-08-12 2005-05-26 Genvac Aerospace Corp Procede et appareil pour oscillateur a ondes regressives biplanaire
CN1871764B (zh) * 2003-08-12 2012-07-11 曼哈顿技术有限责任公司 双平面返波振荡器的方法和装置
WO2008008504A2 (fr) * 2006-07-13 2008-01-17 Manhattan Technologies, Llc Appareil et procédé pour produire des oscillations électromagnétiques
WO2008008504A3 (fr) * 2006-07-13 2008-11-27 Manhattan Technologies Llc Appareil et procédé pour produire des oscillations électromagnétiques
US7679462B2 (en) 2006-07-13 2010-03-16 Manhattan Technologies, Llc Apparatus and method for producing electromagnetic oscillations
US20100045160A1 (en) * 2008-08-20 2010-02-25 Manhattan Technologies Ltd. Multibeam doubly convergent electron gun
US8723137B1 (en) * 2012-10-17 2014-05-13 Innosys, Inc Hybrid magnet for vacuum electronic device

Also Published As

Publication number Publication date
IT992766B (it) 1975-09-30
FR2195838B1 (fr) 1977-02-25
FR2195838A1 (fr) 1974-03-08
IL42696A (en) 1976-02-29
JPS49124962A (fr) 1974-11-29
GB1406938A (en) 1975-09-17
IL42696A0 (en) 1973-10-25
DE2338061A1 (de) 1974-02-21

Similar Documents

Publication Publication Date Title
US3787747A (en) Periodic magnetically focused beam tube
US3558967A (en) Linear beam tube with plural cathode beamlets providing a convergent electron stream
US2797360A (en) Travelling wave amplifiers
US2410054A (en) Electron discharge apparatus
US4395655A (en) High power gyrotron (OSC) or gyrotron type amplifier using light weight focusing for millimeter wave tubes
US3450930A (en) Permanent magnet focused linear beam tube employing a compensating magnet structure between the main magnet and the beam collector
US3398315A (en) A traveling wavetube with improved thermal and magnetic circuitry
US2852715A (en) High frequency structure
US7315126B2 (en) Folded waveguide traveling wave tube having polepiece-cavity coupled-cavity circuit
US3013173A (en) Magnetic beam focusing method and apparatus
GB892535A (en) Travelling wave electron tube apparatus
US3832596A (en) Magnetic structure for focusing of linear beams
US2485401A (en) Magnetron
US3896329A (en) Permanent magnet beam focus structure for linear beam tubes
US7116051B2 (en) Multibeam klystron
US4339694A (en) Flat cathode ray tube
US3273006A (en) Traveling wave tube having a contoured anode collecting surface
US5534747A (en) Variable focus electron gun assembly with ceramic spacers
EP0018402B1 (fr) Canon electronique avec grille de commande portee au potentiel cathodique
US3392308A (en) Crossed field tube having a pair of permanent magnets of different magn etomotive force
RU2337425C1 (ru) Многолучевая миниатюрная "прозрачная" лампа бегущей волны
US3322997A (en) Permanent magnet focused klystron
US3522469A (en) Magnetic beam focusing structure for a traveling wave tube employing magnetic shunts between the pole pieces and the emitter
US3300678A (en) Traveling wave tube with plural pole piece assemblies defining a vacuum sealed tube body and particular collector structure
US4041349A (en) Travelling wave tubes