US2985790A - Backward wave tube - Google Patents

Backward wave tube Download PDF

Info

Publication number
US2985790A
US2985790A US288437A US28843752A US2985790A US 2985790 A US2985790 A US 2985790A US 288437 A US288437 A US 288437A US 28843752 A US28843752 A US 28843752A US 2985790 A US2985790 A US 2985790A
Authority
US
United States
Prior art keywords
wave
electron
path
circuit
along
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
US288437A
Other languages
English (en)
Inventor
Kompfner Rudolf
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
Priority to BE520013D priority Critical patent/BE520013A/xx
Priority to NLAANVRAGE7902950,A priority patent/NL178359B/xx
Priority to NL94448D priority patent/NL94448C/xx
Application filed by English Electric Valve Co Ltd filed Critical English Electric Valve Co Ltd
Priority to US288437A priority patent/US2985790A/en
Priority to GB11762/53A priority patent/GB740998A/en
Priority to FR1080027D priority patent/FR1080027A/fr
Priority to DEN7193A priority patent/DE1084322B/de
Application granted granted Critical
Publication of US2985790A publication Critical patent/US2985790A/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
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/36—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field
    • H01J25/40—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and without magnet system producing an H-field crossing the E-field the backward travelling wave being utilised

Definitions

  • This invention relates to microwave apparatus and more particularly to' such apparatus which employs interaction between an electron stream and an oppositely directed or backward traveling wave.
  • the invention is directed to a microwave oscillator which can be swept electronically over a wide band of frequencies.
  • the invention provides a frequency modulator in which an oscillatory frequency is varied in accordance with modulating information.
  • such as amplifier has been adapted for use as a microwave oscillator by returning a portion of the radio frequency energy from an output circuit connection of high signal level to an input circuit connection of low signal level to sustain .oscillations.
  • Feedback of this kind has been provided between output and input circuit connections either by external paths or internally as a result of wave reflections.
  • the oscillations occur at the frequency of maximum loop gain (so long as it initially exceeds unity) at which the phase shift around the loop is an integral number of 21r radians and will be stable at this frequency so long as the loop gain remains at least unity and the phase shift remains an integral number of Zn radians.
  • traveling wave tubes which include a dispersive circuit (one in which the phase velocity of wave propagation is dependent on the frequency of propagation), the frequency of maximum gain depends strongly on the beam velocity, which is controlled by the beam voltage.
  • the total phase change around a closed loop between input and output connections is kept constant and equal to an integral number of 21r radians as the frequency of maximum gain is varied by changes in the beam voltage, there should result an electronically tuned oscillator.
  • hitherto it has been found difcult to obtain oscillations continuously over a wide frequency band in arrangements of this type since it has been inconvenient to provide that the conditions for oscillations on the loop gain and phase shift be automatically maintained continuously over a wide band of frequencies.
  • an oscillator in accordance with the present invention rather than a single closed loop around which the number of wavelengths must be an integer at the oscillatory frequency, there is instead a multiplicity of closed loops, each of which remains automatically an integral number of wavelengths long as the frequency of oscillations varies.
  • each of these closed loops includes, as a component thereof, an electronic feedback path.
  • An important feature of the present invention is electronic feedback coupling by which the electron beam acts to return energy from points of higher level to points of lower level along the electron stream for sustaining oscillations. It is a characteristic of such electronic feedback that the phase shift associated therewith can be varied by changing the velocity of the beam which in turn is controlled by the beam accelerating voltage.
  • the invention utilizes interaction between an electron stream and an oppositely directed or backward traveling wave. There is described in an article entitled A Spatial Harmonic Amplifier for Six Millimeters Wavelengths by S.
  • the oscillatory output energy is abstracted upstream along the wave path which is the region of higher energy levels for interaction of the kind described. Moreover, for operation over a wide frequency band, it is also in accordance with the invention to terminate the downstream end of the wave path to inhibit reflections there. In this way, substantially all the wave energy available at the upstream end of the wave path is the result of interaction in a backward propagating mode.
  • downstream and upstream refer to the direction of electron flow and the direction opposed to the direction of electron flow, respectively, so that the downstream end of the wave path or tube is the end at which the target electrode is placed while the upstream end is the end at which the electron source is located.
  • expressions such as upstream relative to and downstream of mean on the electron source side of and on the target electrode side of, respectively.
  • an electron source and a target electrode define a path of electron flow along which is positioned a dispersive wave guiding structure in which the strength of the interacting component of the field associated with a wave propagating therethrough is made alternately large and small at successive fixed intervals along the structure.
  • the velocity of the electron stream is adjusted to interact with spatial harmonics of an electromagnetic wave excited in the wave guiding structure which travels vary the beam voltage, there is made available a frequency modulator.
  • Fig. 1 is a longitudinal cross section of an embodiment in accordance with the invention which employs a wave guiding structure which has a series of open lateral slots;
  • Figs. 1A, 1B, 1C, and ID are cross sections taken along the lines 1A-1A, 1B-1B, 1C1C, and 1D1D, respectively, of the embodiment shown in Fig. 1;
  • Fig. 2 shows an embodiment which utilizes a ribbon helix as the wave guiding structure
  • Figs. 3A, 3B, and 3C are cross sectional views taken along planes parallel to the side, top and end, of an embodiment which employs an interdigital filter type of wave guiding structure.
  • the traveling wave tube shown by way of example is constructed largely of non-magnetic conducting material (e.g., copper).
  • An elongated copper block forms the main portion of the tube and has an evacuated hollow interior to guide electromagnetic Waves.
  • the wave guiding path includes a series of lateral slots 11 which are regularly spaced for most of the length of the tube.
  • Three longitudinal slots 12 cross lateral slots 11 and extend for substantially the whole length of the tube.
  • the lateral slots 11 are in the nature of resonators and serve to increase the field strength of the wave in their vicinity.
  • the effect of the fins 13 is to reduce the strength of the interacting components of the field.
  • the effect is to make the strength of the interacting component of the field of waves propagating therethrough alternately large and small at successive intervals along the guiding structure.
  • the longitudinal slots 12 serve to increase the space in which the electron stream can interact With propagating waves.
  • Fig. 1A is a section taken between two slots 11, along the line 1A-1A
  • Fig. 1B is a section taken through a slot 11, along the line 1B-1B.
  • the cross section of the hollow interior of the block 10 is rectangular at each slot 11, with the short dimension vertical.
  • the cross section of the hollow interior of the block 10 between slots 11 is much the same, as shown in Fig. 1A, except that a rectangular fin 13 extends down into the interior from the center of the top of the hollow interior.
  • the spaces between adjacent fins 13 form the slots 11.
  • the bottom edges of the fins 13 contain three spaced longitudinal slots 12 which extend for substantially the whole length of the tube.
  • an end slot 14 This slot is slightly shallower and narrower than the remaining slots 11 for improved matching.
  • a short connecting section 15 To the left of slot 14 is a short connecting section 15, a cross section, taken along the line 1C--1C, being shown in Fig. 1C.
  • the connecting section is of the same cross section as the between-the-slot cross section of Fig. 1A, except that the sections of the fin between longitudinal slots 12 extend to the bottom of the opening to provide a radio frequency short at the end of the wave guiding path.
  • block 10 has a hollow interior of rectangular cross section to provide space for a cathode 16 and a control grid 17.
  • An accelerator grid 18 also occupies part of the space to the left of connecting section 15, comprising a fiat molybdenum plate of rectangular cross section with a central screened rectangular aperture.
  • the molybdenum plate is flush against the right-hand end of the open space and the aperture is aligned with passage and fins 13.
  • the aperture and the previously described end section determine the shape of an electron stream which is projected past fins 13, the shape being approximately that shown by the dotted outlines 19 in Figs. 1A and 1B.
  • An oxide coated nickel cathode 16 is located in the left-hand portion of the open space.
  • Cathode 16 is rectangular in cross section and its oxide coated surface faces to the right and is aligned with the aperture in the plate comprising accelerator grid 18.
  • Cathode 16 has a hollow interior and contains a heating coil 20 which will be described later.
  • Control grid 17 is located between cathode 16 and accelerator grid 18. It comprises a thin molybdenum plate with a rectangular screened aperture which is also aligned with the aperture in the plate comprising accelerator grid 18. The manner in which both cathode 16 and control grid 17 are supported will also be described later.
  • Fig. 1 Just to the right of the fin 13 farthest to the right in Fig. 1 is an end slot 21 which corresponds to slot 14 on the left.
  • C01- lector 23 is a flat rectangular molybdenum plate and is aligned with section 22 and fins 13 to intercept the electrons which are projected past fins 13. The manner in which collector 23 is supported will be described later.
  • end slot 14 is connected to output wave guide 24 by a tapered wave guide 25.
  • Wave guide 24 is of standard rectangular cross section and its long dimension is normal to the plane of the drawing.
  • Wave guide 25 is also of rectangular cross section, and is tapered to act as an impedance transformer. A short distance below the base of rectangular guide 25, block 10 terminates in a flat circular face which projects somewhat from the rest of block 10.
  • An annular slot 27 opens on the fiat circular face of block 10 and surrounds guide 25, serving as a radio frequency choke.
  • the interior of block 10 is sealed off by a glass window 28, which is separated slightly from the face of block 10 and situated directly below guide 25.
  • Window 28 is held in place by a molybdenum cup 29 which surrounds the projecting portion of block 10 and is brazed to block 10 outside of chock 27.
  • the end of wave guide 24 is enlarged to fit over the raised portion of block 10 and make contact with block 10 without touching molybdenum cup 29. Except for a circular flange which surrounds cup 29, guide 24 is terminated in a fiat circular face which is parallel to the face of block 10 and is located just below it on the other side of glass window 28.
  • the rectangular interior of guide 24 is aligned with guide 25 and is similarly surrounded by an annular slot 30, which serves as a radio frequency choke.
  • the wave guiding path is suitably terminated to minimize internal reflections therefrom.
  • a wedge 31 of ceramic material with suitable lossy material for example, colloidal graphite.
  • the cross section of the wedge increases in the direction of electron flow and the wedge extends advantageously over several wavelengths of the wave guiding structure.
  • the entire tube extends lengthwise between two poles 55 and 56 of an electromagnet which supplies a longitudinal beam focussing magnetic field.
  • Fig. 1D shows a section of the tube taken through cathode 16, along the line lD-lD, illustrating the manner in which cathode 16 is supported and the manner in which it is heated.
  • one end of heating coil 20 is embedded in cathode 16.
  • the other end of coil 20 is attached tov a tungsten rod 38.
  • Cathode 16 is attached to another parallel tungsten rod 39, both rods extending out of the tube, to the right in Fig. 1D, and out normal to the plane of the drawing in Fig. 1.
  • a copper sleeve 40 surrounds rods 38 and 39 and fits tightly into the side wall of block 10, forming a passage out of the tube.
  • a short molybdenum sleeve 41 is brazed to the end of sleeve 40 and a glass cap 42 is sealed to the end of sleeve 41.
  • Rods 38 and 39 extend through the end of glass cap 42.
  • a heater potential source 43 is connected between rods 38 and 39, causing cathode 16 to be heated and its oxide coated face to emit a stream of electrons.
  • control grid 17 is attached to a tungsten rod 44 which extends upwardly out of the tube.
  • a copper sleeve 45 fits tightly into the top wall of block to form a passage out of the tube.
  • a short molyb-. denum sleeve 46 is brazed to the end of'sleeve 45 and a glass cap 47 is sealed to the end of sleeve 46.
  • Rod 44 extends through the end of glass cap 47 and is connected to the positive terminal of a biasing voltage supply 48, the negative terminal of which is connected to rod 39, as shown in Fig. 1D.
  • Fig. 1 shows a connection from the negative terminal of voltage supply 48 passing through the left end wall of the tube, such a representation is only schematic and is for the purpose of depicting a complete circuit. The actual connection is to the end of rod 39 as shown in Fig. 1D.
  • the collector electrode 23 at the right-hand end of the tube is attached to a tungsten rod 49 which extends through an opening in the top of block 10.
  • a copper sleeve 50 surrounds rod 47 and fits snugly into block 10 to form a passageway out of the tube.
  • a short molybdenum sleeve 51 is brazed to the end of sleeve 50, and a glass cap 52 is sealed to the end of molybdenum sleeve 51.
  • Rod 47 extends through the end of glass cap 52 and is connected to the positive side of a battery 53.
  • the negative side of battery 53 is connected directly to copper block 10, which is also grounded.
  • the negative side of voltage supply 53 is also connected to the positive terminal of a main beam accelerating voltage supply 54 which is made variable.
  • the negative terminal of voltage supply 54 is connected to the negative terminal of voltage supply 48.
  • an electron stream can be made to interact with a backward traveling wave.
  • the velocity of the electron stream is adjusted so that in the time that an electron traverses the distance between the slots where the interacting field component is high, the backward Wave travels an integral number of wavelengths less substantially this same distance.
  • the intermittent wave circuit shown can be considered a filter type iterative circuit. If there is set up in the circuit a wave which travels along the circuit in a direction opposite to the electron flow,
  • w is the angular frequency of the backward travel-r ing wave
  • d is the average length along the path of electron flow of one filter section, it is an integer
  • B is the phase displacement per section of the backward wave.
  • This bunched electron group moves downstream and at succeeding slots interacts with that portion of the excited wave then at these slots. If the relative velocities of the stream and excited wave are as described, the group of electrons will see the same phase of the excited wave at the successive slots, and, accordingly, the electron stream will be periodically velocity modulated and bunched as it moves downstream, while the excited backward traveling Wave will similarly grow in amplitude as it proceeds upstream along the wave guiding path.
  • varying the beam velocity can be made to vary the frequency of maximum gain.
  • the frequency of maximum gain varies accordingly.
  • the phase shift around each of the circulating loops remain an integral number of 21r radians, as this frequency of maximum gain varies. It can easily be shown with reference to Fig.
  • phase change from the yth slot to the xth slot moving along with the excited circuit wave in the backward direction, plus the phase change from the xth slot to the yth slot moving with the electron beam in the forward direction is an integral multiple of 21r if the velocity of the electron flow and the phase velocity of the circuit wave satisfy the condition that a given group of electrons see a corresponding phase of the electric field of the wave at each slot.
  • Such a swept oscillator is adaptable to a variety of uses.
  • modulating voltages derived from a source 57 of signal information on the steady beam voltage, there can be achieved frequency modulation in accordance with the signal information of a base frequency corresponding to the steady beam voltage. It is of course possible to employ various other arrangements to vary the beam velocity past the wave guiding structure in accordance with modulating information.
  • the dissipative blocks inserted there are designed to minimize reflections over the entire band of wavelengths which are likely to propagate along the wave guiding structure. In this way, there are prevented oscillations due to reflected forward waves which might otherwise interfere with the desired backward oscillatory Wave. Moreover, this expedient also tends to improve the uniformity as a function of frequency of the output level of backward oscillations.
  • the circuit structure should have a high impedance effectively constant and a low circuit loss over a wide frequency band when supporting a backward mode of propagation. Additionally, the circuit should be easily matched to conventional output circuits over a wide frequency band.
  • FIG. 2 shows schematically an oscillator 60 wherein there is incorporated a ribbon helix type of wave circuit which can be advantageously employed in cooperation with a cylindrical beam.
  • the various tube elements are enclosed in an evacuated tubular envelope 61 which preferably is of a non-magnetic metal such as copper.
  • the electron source 62 which is shown schematically (for simplicity in the drawings) as a cylindrical electron emissive cathode.
  • the target electrode 63 which defines with the electron source a longitudinal path of electron flow.
  • Beam accelerating voltage is provided by the beam voltage source 70.
  • the wave circuit which comprises a ribbon conductor 64 helically wound or otherwise fashioned, for example, to have a distance around one turn substantially equal to one half the average wavelength in the frequency band planned for operation.
  • the electron source preferably is adapted to provide a hollow cylindrical beam whose flow is parallel and contiguous to the broad dimension of the ribbon conductor and coaxial with the helix.
  • This particular embodiment is designed to have the stream flow past the inner surface of the ribbon helix, although it is feasible to have the flow past the outer surface, or past both surfaces simultaneously.
  • Output waves are derived for utilization at the upstream end of the wave circuit in accordance with one feature of the invention.
  • a wave guide 65 which is of standard rectangular cross section with its long dimension normal to the plane of the drawing and which forms by way of the vacuum-tight glass window 66 a continuation of transmission path to suitable utilization apparatus, is coupled to the upstream end of the helix wave circuit for abstracting wave energy therefrom in the manner well known in the art of abstracting wave energy from a helix wave circuit.
  • One convenient technique for achieving a suitable wave circuit of this kind is to groove a hollow metallic cylinder along a suitable helical path.
  • the wave circuit shown is of this construction.
  • a thin-walled cylinder 67 of length sufficient to extend from the output wave guide to a point short of the target electrode is grooved as shown along a helical path 69 which thereafter becomes the gaps between helix turns.
  • the pitch of the helical grooving is tapered, in the manner well known in the art for improving helix terminations.
  • a suitable dissipative termination which for example, as shown comprises a cylindrical ceramic block 68 which surrounds the downstream end of the helix circuit and is apertured for passage of the electron flow in a truncated right circular cone having its base at the upstream end of the block and coated along its inside surface with suitable lossy material.
  • this embodiment resembles that shown in Fig. 1.
  • the ribbon helix provides an intermittent interaction wave guiding path in which when waves propagate along the helix ribbon the gaps 69 between turns are characterized by high axial electric fields whereas the longer regions adjacent the helix turns are characterized by substantially lower axial electric fields. Accordingly. the path of travel for a particular group of electrons will encounter periodic intervals of high interacting field com-- ponents interspersed with regions of lower interacting field components. As before, the velocity of electron flow is adjusted by means of the voltage supply 70 so that a particular group of electrons will interact at the intervals of high field with corresponding phases of a backward traveling wave.
  • the velocity of the stream is made such that while an electron traverses the average distance between turns, the backward traveling wave traverses an integral number of wavelengths less the average distance between turns. Accordingly, when the electron beam current reaches a sutficient value, noise components in the stream excite a backward traveling wave which interacts with the electron flow for providing an oscillatory output at the upstream end of the wave guide.
  • An oscillator of this kind similarly can be adapted for application as a frequency modulator by the insertion in series with the steady beam accelerating voltage 70 of modulating voltages supplied from a suitable information channel.
  • Figs. 3A, 3B, and 3C show schematically side, top, and end sections of a backward wave oscillator 80 which utilizes an interdigital type wave circuit.
  • the elongated evacuated envelope 81 for example of rectangular cross section, is of a non-magnetic metal, such as copper.
  • an electron source 82 and a target electrode 83 therebetween define a longitudinal path of electron flow, which, for example, can be a hollow cylindrical beam.
  • Magnetic focussing is employed to minimize transverse components of electron flow in the manner described above.
  • Beam accelerating potential is supplied by the voltage supply 90 which maintains the electron source at a negative potential with respect to the envelope.
  • a loaded wave guide 84 which comprises the intermediate portion of the tube loaded by means of two rows or sets 85 of regularly spaced conductive fins or fingers 86 extending in a linear array in an interdigital pattern from the two opposite broad inner surfaces of the envelope. Each row is parallel to and on opposite sides of the tube axis. Each of the fingers extend normal to the path of flow. Two separate rows are used in this instance to provide two parallel circuits as a result of which more eflicient use is made of a given tube length.
  • the length of the fins of each row increase at the upstream or output end gradually towards the center section which comprises a multiplicity of fins of uniform length.
  • the dimensions and spacing of the fingers are adjusted to provide phase velocities to backward traveling waves suitable for interaction with electron streams of velocities conveniently realized.
  • the length of each of the fingers along the main region of the circuit is sufficient to have the fingers projecting from one surface interleave with the fingers projecting from the opposite surface for forming longitudinal gaps 91 between successive fingers. Adjacent these regions of finger interleaving along the path of flow, there results a succession of relatively long regions adjacent to the fingers interspersed with the shorter longitudinal gaps between fingers. Accordingly, as in the wave circuits previously described in connection with Figs. 1 and 2, when an appropriate electromagnetic wave propagates along the structure, the longitudinal component of the electric field along the path of flow is made alternatively large and small corresponding, respectively, to the longitudinal gaps between fingers and the longer drift regions adjacent the fingers.
  • oscillatory power is abstracted for utilization at the upstream end of the wave circuit by way of an output connection which comprises a conventional rectangular.
  • wave guide 87 having its broad dimension parallel to, the direction of electron flow.
  • This wave guide connection 87 is provided with a pressure-tight window'88 by way of which output energy may be abstracted for utilization.
  • This wave guide connection makes a right angle bend with the elongated portion of the tube envelope which comprises the wave circuit and, accordingly, a 45 degree deflection plate 89 is provided at the bend in the manner known to the art for diverting the waves traveling longitudinally along the tube to the output wave guide 87.
  • This plate 89 is provided with a cylindrical aperture 92 for passage therethrough of th electron flow.
  • the reflectionless terminations are provided downstream along the wave path to inhibit reflections upstream therefrom.
  • ceramic members 93 suitably coated with lossy material are inserted at the downstream end, arranged obliquely on each side of the linear arrays as shown in Fig. 3B.
  • the electron velocity is made such that while an electron traverses the average distance between successive gaps, the wave traverses an integral number of half wavelengths less substantially this average distance.
  • the velocity of the electrons would be adjusted to be substantially equal to col where w is the frequency of the backward traveling wave, 1 is the average distance along the path of electron flow between successive gaps, n is an integer, and 0 is the phase displacement of the wave between successive gaps.
  • this interdigital structure is treated for purposes of analysis as a plurality of iterative filter sections, each section comprising a pair of adjacent fingers and associated gaps, for interaction the velocity of the electron stream is adjusted so that while a given electron travels along the electron path the length of one filter section, the backward traveling wave traverses an integral number of wavelengths less this same length.
  • the velocity of the electron stream should be such that where d is the average length of a filter section i.e. the average distance between successive like gaps, and B is the phase displacement per filter section of the backward wave. It can be seen that this relationship is similar to that derived for the wave circuits shown in Figs. 1 and 2.
  • modulating signals are superimposed on the beam potential provided by the voltage supply for varying the beam velocity.
  • any of the structures herein disclosed may be used as a microwave amplifier by substituting for the reflectionless terminations shown at the downstream end of the tube a suitable reflectionless input connection for supplying electromagnetic energy to the wave guiding circuit.
  • a suitable reflectionless input connection for supplying electromagnetic energy to the wave guiding circuit.
  • Microwave apparatus comprising an electron source and an electrode for producing an electron stream, a source of potential for accelerating the flow of said electrol stream, a wave guiding structure for transmitting electromagnetic waves in a direction opposite to the flow of said electron stream and in interacting relationship therewith, and output means coupled to said wave guiding structure at the end thereof adjacent said electron source for abstracting therefrom electromagnetic wave energy
  • said wave guiding structure including an elongated envelope having two opposite inner surfaces extending along the path of said electron stream, and a pair of rows of longitudinally spaced conductive elements projecting from said surfaces parallel to and on opposite sides of said path, the elements of each row projecting alternately from the opposite surfaces of said envelope in interdigital relationship to form longitudinal gaps between successive elements in each row, said gaps being narrower than the dimensions of said elements, parallel to said path, said elements being so arranged that each element of each row is positioned transversely References Cited in the file of this patent UNITED STATES PATENTS 2,603,773 Field July 15, 1952 2,683,238 Millman July 6, 1954 2,

Landscapes

  • Particle Accelerators (AREA)
  • Microwave Tubes (AREA)
US288437A 1952-05-17 1952-05-17 Backward wave tube Expired - Lifetime US2985790A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE520013D BE520013A (fr) 1952-05-17
NLAANVRAGE7902950,A NL178359B (nl) 1952-05-17 Elektrostatische kopie-inrichting.
NL94448D NL94448C (fr) 1952-05-17
US288437A US2985790A (en) 1952-05-17 1952-05-17 Backward wave tube
GB11762/53A GB740998A (en) 1952-05-17 1953-04-28 Travelling wave tube
FR1080027D FR1080027A (fr) 1952-05-17 1953-05-04 Tube à ondes rétrogrades
DEN7193A DE1084322B (de) 1952-05-17 1953-05-16 Mikrowellengenerator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US288437A US2985790A (en) 1952-05-17 1952-05-17 Backward wave tube

Publications (1)

Publication Number Publication Date
US2985790A true US2985790A (en) 1961-05-23

Family

ID=23107094

Family Applications (1)

Application Number Title Priority Date Filing Date
US288437A Expired - Lifetime US2985790A (en) 1952-05-17 1952-05-17 Backward wave tube

Country Status (6)

Country Link
US (1) US2985790A (fr)
BE (1) BE520013A (fr)
DE (1) DE1084322B (fr)
FR (1) FR1080027A (fr)
GB (1) GB740998A (fr)
NL (2) NL178359B (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264515A (en) * 1961-06-29 1966-08-02 Varian Associates Collinear termination for high energy particle linear accelerators
US3353057A (en) * 1963-07-12 1967-11-14 Matsushita Electronics Corp Traveling-wave tube having a comb delay line formed on a ridge in a first waveguideand a plurality of connecting ridge waveguides
US3377572A (en) * 1961-10-24 1968-04-09 Csf Delay structure
US3414756A (en) * 1965-12-28 1968-12-03 Sfd Lab Inc Impedance matched periodic microwave circuits and tubes using same
DE3228172A1 (de) * 1981-07-29 1983-02-17 Varian Associates, Inc., 94303 Palo Alto, Calif. Verzoegerungsleitung fuer eine wanderfeldroehre
US8169611B2 (en) 2009-02-27 2012-05-01 University Of Nebraska Board Of Regents Terahertz-infrared ellipsometer system, and method of use
US8416408B1 (en) 2009-02-27 2013-04-09 J.A. Woollam Co., Inc. Terahertz-infrared ellipsometer system, and method of use
US8488119B2 (en) 2009-02-27 2013-07-16 J.A. Woollam Co., Inc. Terahertz-infrared ellipsometer system, and method of use
US8736838B2 (en) 2009-02-27 2014-05-27 J.A. Woollam Co., Inc. Terahertz ellipsometer system, and method of use
US8934096B2 (en) 2009-02-27 2015-01-13 University Of Nebraska Board Of Regents Terahertz-infrared ellipsometer system, and method of use

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899594A (en) * 1959-08-11 johnson
US2955226A (en) * 1955-06-13 1960-10-04 Univ California Backward-wave amplifier
US2945981A (en) * 1955-06-13 1960-07-19 Bell Telephone Labor Inc Magnetron-type traveling wave tube
US2748268A (en) * 1955-06-15 1956-05-29 Hughes Aircraft Co Backward-wave oscillator mixer
US2869019A (en) * 1955-07-07 1959-01-13 Hughes Aircraft Co Reflex space-harmonic oscillator
US2963615A (en) * 1955-07-22 1960-12-06 Hughes Aircraft Co Broadband traveling-wave amplifier
US2906914A (en) * 1955-08-18 1959-09-29 Bell Telephone Labor Inc Traveling wave tube
US3065373A (en) * 1955-11-29 1962-11-20 Bell Telephone Labor Inc High frequency apparatus of the traveling wave type
US2890372A (en) * 1956-02-23 1959-06-09 Raytheon Mfg Co Traveling wave amplifiers
US2925521A (en) * 1957-04-05 1960-02-16 Raytheon Co Traveling wave tubes
US2942142A (en) * 1957-08-30 1960-06-21 Raytheon Co Traveling wave oscillator tubes

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2603773A (en) * 1948-12-09 1952-07-15 Bell Telephone Labor Inc Modulated oscillator
US2683238A (en) * 1949-06-17 1954-07-06 Bell Telephone Labor Inc Microwave amplifier
US2708236A (en) * 1950-03-18 1955-05-10 Bell Telephone Labor Inc Microwave amplifiers
US2801361A (en) * 1948-12-10 1957-07-30 Bell Telephone Labor Inc High frequency amplifier
US2801359A (en) * 1952-04-01 1957-07-30 Bell Telephone Labor Inc Traveling wave tube
US2880355A (en) * 1952-04-09 1959-03-31 Csf Backward flow travelling wave oscillators
US2932760A (en) * 1951-04-13 1960-04-12 Csf Backward flow travelling wave devices

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL77941C (fr) * 1947-06-07
FR979095A (fr) * 1948-11-26 1951-04-23 Csf Perfectionnement aux tubes amplificateurs à ondes progressives

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2603773A (en) * 1948-12-09 1952-07-15 Bell Telephone Labor Inc Modulated oscillator
US2801361A (en) * 1948-12-10 1957-07-30 Bell Telephone Labor Inc High frequency amplifier
US2683238A (en) * 1949-06-17 1954-07-06 Bell Telephone Labor Inc Microwave amplifier
US2708236A (en) * 1950-03-18 1955-05-10 Bell Telephone Labor Inc Microwave amplifiers
US2932760A (en) * 1951-04-13 1960-04-12 Csf Backward flow travelling wave devices
US2801359A (en) * 1952-04-01 1957-07-30 Bell Telephone Labor Inc Traveling wave tube
US2880355A (en) * 1952-04-09 1959-03-31 Csf Backward flow travelling wave oscillators

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264515A (en) * 1961-06-29 1966-08-02 Varian Associates Collinear termination for high energy particle linear accelerators
US3377572A (en) * 1961-10-24 1968-04-09 Csf Delay structure
US3353057A (en) * 1963-07-12 1967-11-14 Matsushita Electronics Corp Traveling-wave tube having a comb delay line formed on a ridge in a first waveguideand a plurality of connecting ridge waveguides
US3414756A (en) * 1965-12-28 1968-12-03 Sfd Lab Inc Impedance matched periodic microwave circuits and tubes using same
DE3228172A1 (de) * 1981-07-29 1983-02-17 Varian Associates, Inc., 94303 Palo Alto, Calif. Verzoegerungsleitung fuer eine wanderfeldroehre
US8416408B1 (en) 2009-02-27 2013-04-09 J.A. Woollam Co., Inc. Terahertz-infrared ellipsometer system, and method of use
US8169611B2 (en) 2009-02-27 2012-05-01 University Of Nebraska Board Of Regents Terahertz-infrared ellipsometer system, and method of use
US8488119B2 (en) 2009-02-27 2013-07-16 J.A. Woollam Co., Inc. Terahertz-infrared ellipsometer system, and method of use
US8705032B2 (en) 2009-02-27 2014-04-22 J.A. Woollam Co., Inc Terahertz-infrared ellipsometer system, and method of use
US8736838B2 (en) 2009-02-27 2014-05-27 J.A. Woollam Co., Inc. Terahertz ellipsometer system, and method of use
US8934096B2 (en) 2009-02-27 2015-01-13 University Of Nebraska Board Of Regents Terahertz-infrared ellipsometer system, and method of use
US9041927B1 (en) 2009-02-27 2015-05-26 J.A. Woollam Co., Inc Terahertz-infrared ellipsometer system, and method of use
US9121757B2 (en) 2009-02-27 2015-09-01 J.A. Woollam Co., Inc. Terahertz ellipsometer system, and method of use

Also Published As

Publication number Publication date
NL94448C (fr)
GB740998A (en) 1955-11-23
FR1080027A (fr) 1954-12-06
NL178359B (nl)
BE520013A (fr)
DE1084322B (de) 1960-06-30

Similar Documents

Publication Publication Date Title
US2985790A (en) Backward wave tube
US2932760A (en) Backward flow travelling wave devices
US2683238A (en) Microwave amplifier
US2541843A (en) Electronic tube of the traveling wave type
US2801361A (en) High frequency amplifier
US3221205A (en) Traveling-wave tube with trap means for preventing oscillation at unwanted frequencies
US2595698A (en) Electron discharge device and associated circuit
US2880355A (en) Backward flow travelling wave oscillators
US2891191A (en) Backward wave tube
US2888597A (en) Travelling wave oscillator tubes
US2957103A (en) High power microwave tube
US2858472A (en) Slow-wave circuit for a traveling wave tube
US2889486A (en) Interdigital delay line
US2730649A (en) Traveling wave amplifier
US2802135A (en) Traveling wave electron tube
US2812468A (en) Spatial harmonic traveling wave tube
US2806975A (en) Transition from bifilar helix to waveguide for backward wave oscillator
US2916658A (en) Backward wave tube
US2843791A (en) Traveling wave tube
US2895071A (en) Traveling wave tube
US2800602A (en) Low noise electron discharge tubes
US3069587A (en) Travelling wave device
US2945981A (en) Magnetron-type traveling wave tube
US3527976A (en) Log periodic electron discharge device
US3571651A (en) Log periodic electron discharge device