US2916657A - Backward wave amplifier - Google Patents

Backward wave amplifier Download PDF

Info

Publication number
US2916657A
US2916657A US288438A US28843852A US2916657A US 2916657 A US2916657 A US 2916657A US 288438 A US288438 A US 288438A US 28843852 A US28843852 A US 28843852A US 2916657 A US2916657 A US 2916657A
Authority
US
United States
Prior art keywords
wave
electron
path
along
guide
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
US288438A
Other languages
English (en)
Inventor
Kompfner Rudolf
Neal T Williams
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories 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
Priority to NLAANVRAGE7306318,A priority Critical patent/NL175617B/xx
Priority to BE520002D priority patent/BE520002A/xx
Priority to US150429A priority patent/US2708236A/en
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US288438A priority patent/US2916657A/en
Priority to FR1068806D priority patent/FR1068806A/fr
Priority to GB13243/53A priority patent/GB742739A/en
Application granted granted Critical
Publication of US2916657A publication Critical patent/US2916657A/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
    • 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
    • H01J23/24—Slow-wave structures, e.g. delay systems

Definitions

  • This invention relates to microwave amplifiers and more particularly to such amplifiers which utilize for amplification the interaction between an electron stream and an oppositely directed or backward traveling electromagnetic wave.
  • the traveling wave tube can be described as a vacuum.
  • the electrons are caused to travel I along in substantial synchronism with the wave, a particular group of electrons interacting with substantially the same portion of the wave at all times.
  • the electron stream and the electromagnetic wave do not move along in substantial synchronism, but instead a discontinuous or intermittent type of interaction is employed.
  • the electromagnetic wave is transmitted over a guiding structure in which the strength of the interacting component of the field associated with the wave is made alternately large and small at successive fixed intervals along the guiding structure and a stream of electrons is projected in the direction of wave propagation in an interacting relationship with the wave and at a velocity considerably lower than the phase velocity of the wave.
  • the velocity of the electron flow is adjusted so that while an electron traverses the average distance between adjacent intervals in which the interacting component of the field is high, the wave traverses substantially the same distance plus an integral number (e.g., one) of wavelengths. In this way, a given group of electrons interacts with like portions of the wave as it traverses successive intervals in which interacting field strength is high.
  • Wave guiding struc tures of this kind can be termed discontinuous or intermittent interaction type structures and operation of the kind described above inwhich a group of electrons interacts with like portions of the wave instead of thesame portion of the wave can be termed spatial harmonic operation.
  • the present invention is directed primarily at a traveling wave tube which utilizes for amplification a discontinuous interaction type circuit to provide interaction between an electron stream and the spatial harmonics of an oppositely directed traveling wave.
  • Fig. 1 represents a longitudinal cross section of a backward wave amplifier in accordance with the invention which employs an intermittent interaction ,type circuit which comprises a periodic series of lateral slots;
  • Figs. 1A, 1B, 1C and ID are cross sections taken along the lines 1A1A, 1B1B,1C-1C, and 1D1D, respectively, of the amplifier shown in Fig. 1;
  • Fig. 2 is a side section of a second embodiment of the invention in which a ribbon helix is utilized as the wave guiding circuit; and Y Figs. 3A, 3B, and 3C are a side section, a top section, and across section, respectively, of a traveling wave tube embodiment of the invention incorporating an interdigital type wave guiding circuit.
  • the travelingwave tube shown is constructed largely of non-magnetic conducting material (e.g., copper).
  • An elongated copper block 10 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. cross lateral slots 11 and extend for substantially the whole length of the tube.
  • Fig. 1A is a; section taken between two slots 11, along the line 1A 1A, while Fig. 1B is a section taken through a slot 11, along the line 1B--1B.
  • the cross-section 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 edges of the fins 13 contain three spaced longitudinal slots 12 which extend for substantiallythe Whole length of the tube.
  • the slots 11 are in the nature of resonators Three longitudinal slots 12 or the hollow' 24. A short distance above the base of and serve to increase the field strength of waves propagating in the structure of their vicinity. Between slots 11, the effect of the projecting conductive fins is to reduce the strength of the interacting component of the field. 'The-effectis to make the strength of the interacting component of the field of the traveling wave alternately large and small along the guiding structure.
  • the longitudinal slots 12 serve to increase the space in which the electron stream can interact with the traveling wave.
  • an end slot 14 Just to the left of the fin 13 farthest to the left, is an end slot 14.
  • a short connecting :section 15 To the left of slot 14 is a short connecting :section 15, a cross-section, taken along the line 1C1C, being shown in Fig. 1C.
  • the connecting section is of the same cross-section as the between-the-slotcross-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 waveguiding path.
  • block 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 comprising a flat molybdenum platetof 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 apertureis aligned with passage 15 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 Fig. 1A.
  • Cathode 16 is located in the lefthand 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 'acceleratorgrid 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.
  • An end slot 21 which corresponds to slot 14 on the left.
  • Collector 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 an output wave guide 24 by a wave-guide transformer 25.
  • Output guide 24 is of standard rectangular crosssection and its long dimension is normal to the plane of the drawing.
  • Transformer 25 is also of rectangular cross-section, but its transverse dimensions are smaller than those of guide 24.
  • Transformer 25 comprises a rectangular hole, substantially a quarter of a wavelength (Le, a quarter of a wavelength in the wave-guiding path) deep, formed in block 10 just above end slot 14.
  • Above transformer 25 is a rectangular wave guide 26, which is of the same cross-section as the interior of wave guide rectangular guide 26, block 10 terminates in a fiat circular face which is raised somewhat from the rest of block 10.
  • An annular slot 27 opens on the fiat circular face of block 10 and surrounds guide 26, 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 I face of block 10 and situated directly over guide 26.
  • Window 28 is held in place by a molybdenum cup 29 which surrounds the raisedportion of block 10 and is brazed to block 10 outside of choke 27.
  • output 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 flat circular face which is parallel to the face of block 10 and is located just above it on the other side of glass window 28. The rectangular interior of guide 24 is aligned with guide 26 and is similarly surrounded by an annular slot 30, which serves as a radio frequency choke.
  • the collector, or input, end of the tube is substantially identical to the electron source or output end.
  • a waveguide transformer 31, corresponding to transformer 25, is located just above end slot 21 and communicates with it.
  • a rectangular wave guide 32, corresponding to guide 26, is just above transformer 31, which opens into it.
  • block 10 terminates a short distance above the bottom of guide 32 in a flat circular face which is raised from the rest of block 10.
  • annular slot33 corresponding to slot 27, opens into theface and surrounds guide 32, serving as a radio frequency choke.
  • a glass window 34 held in place by a molybdenum cup 35, is placed over the opening of guide 32, cup 35 holding window '34 slightly apart from the face of block10.
  • Cup '35 surrounds the raised portion of block 10 and is soldered to it outside of choke 33, sealing the interior of the tube.
  • An input wave guide 36 corresponding to guide 24, has an enlarged end from which an annular flange extends around the periphery of molybdenum cup 35, making contact with block 10 outside of the raised portion.
  • Guide 36 terminates in a circular face which is parallel to the'face of block 10, and the interior of guide 36 is aligned with guide 31.
  • Input guide 36 has an annular slot 37, corresponding to slot 30, which surrounds the opening in the face of guide 36 and serves as a radio frequency choke.
  • Fig. 1B shows a section of the-tube taken through cathode 16, along the line 1D1D, illustrating the manner in which cathode 16 is supported and the manner in which it is heated.
  • heating coil 20 is imbedded in cathode 16.
  • the other end of coil 20 is attached to a tungsten rod 38.
  • Cathode 16 is attached to anotherparallel tungsten rod 39, both rods extending out of the tube, to the right in Fig. 1C 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-an d a glass cap 42 is sealed to the end of sleeve 41.
  • Rods 38 and 39 extend through the end of glass cap 42.
  • Aheaterpotential 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.
  • tungstenrod 44 which extends downward out of the tube.
  • a copper sleeve 45 fits tightly into the bottom wall of block 10 to form a passage out of the tube.
  • a short molybdenumsleeve 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 connectedtothe positive terminal of a biasing battery 48, the negative terminal of which is connected to rod 39, which is shown in Fig. 1D;
  • FIG. 1 shows a connection from the negative terminal of voltage supply 48 passing through theleft end wall of the tube, such a representatiornis 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 atthe right-hand end of the tube is attached to a tungsten rod 49 which extends through an opening in the bottom of-block 10.
  • a copper sleeve 50 surrounds rod 49 and fits snugly into block 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 49 extends through the end of glass cap 52 and is connected to the positive side of a voltage supply 53.
  • the negative side of supply 53 is connected directly to copper block 10, which is also grounded.
  • the negative side of supply 53 is also connected to the positive pole of a main beam accelerating voltage supply 54 which can be varied.
  • the negative pole of supply 54 is connected to the negative terminal of supply 48.
  • the potential supplied by battery 48 is preferably chosen for a value of beam current suited for stable operation.
  • the entire tube extends lengthwise between two poles 55 and 56 of an electromagnet which supplies a longitudinal beam focusing field.
  • an electromagnetic wave to be amplified is supplied to the transmission path through input guide 36, from a source 36a.
  • Source 36a shown schematically, may be any suitable source of electromagnetic waves such as an oscillator, an antenna, or even another traveling wave tube, the output of which it is desirous to amplify.
  • the wave of the dominant mode travels through input guide 36, it has no longitudinal electric field.
  • the nature of the slotted wave-guiding structure is such that the wave propagates along its length with a longitudinal electric field.
  • the slotted structure transmits the wave at a predetermined phase velocity which is to some extent dependent on the wave frequency.
  • An electron beam is projected lengthwise past the slotted structure at a predetermined velocity and interacts with spatial harmonics of the wave in the manner to be described below, causing the wave to grow in amplitude as it progresses to the left.
  • the amplified wave is taken off through output guide 24, with no longitudinal electric field.
  • upstream is meant a point or position in the circuit which is closer to the cathode than a point with which it is being compared.
  • downstream denotes a point or position closer to the collector than a point with which it is being compared.
  • Downstream is also used to denote the direction of electron travel, whereas upstream denotes the direction opposite to that of the electron travel.
  • the relative velocities of the traveling wave and the group of electrons are made such that the wave has progressed in a direction upstream a distance of one wavelength less the distance between the centers of two adjacent slots 11 in the time taken for the electron group to progress down stream the distance between the centers of these two slots.
  • the condition called for is met and the interaction becomes cumulative and gain is achieved.
  • the immediate presence of the conducting fins 13 between the slots prevents interaction with out-of-phase portions of the waves from counteracting gain already secured. From these considerations, it is evident that the gain of the amplifier will be to some extent dependent on the intensity of the electron 'beam current.
  • the electron time taken for an electron to move from one slot to an adjacent slot would have to be or the same as that taken for the wave to travel the same distance.
  • the electron fiow is oppositely directed to the traveling wave, and the time required for an electron to move a distance d is d cod v,T E (3) L0 instead of for the case when the electrons are in synchronism with what might be called the forward wave.
  • E is represented as a sum of Fourier component traveling waves with difierent phase velocities.
  • the electrons may be said to interact with the first Fourier spatial harmonic of the backward electromagnetic wave.
  • the spatial harmonic concept is for purposes of mathematical descrlption only, and that the harmonics have no independent physical existence.
  • a spatial harmonic is to be sharply distinguished from the usual frequency harmonic, in that the concept applies only in the case of traveling waves.
  • the various spatial harmonics may be considered as being waves of the same frequency but of difierent wavelengths and phase velocities.
  • a complex traveling wave such as that which may travel along the wave guiding circuit in Fig, 1, may be completely described in mathematical terms by a series of such waves.
  • Equation 7 From Equation 7 it can be seen that gain-producing interaction may be obtained if the electron stream is syn chronized with any Fourier spatial harmonic of the backward traveling wave. For such interaction to take place, the electron velocity should be substantially equal to where n is the number of the order of the harmonic with which the stream is to interact. It will be convenient to rewrite this expression as cud of suitable voltages for changing the beam accelerating voltage.
  • the slotted structure of Fig. 1 may be considered to comprise an electromagnetic wave transmission path with means (i.e., the resonators or slots 11) for increasing the axial electric field at regular intervals along the tube.
  • the structure may be said to comprise a transmission path with means (i.e., the fins 13) for decreasing the axial electric field at regular intervals along the tube.
  • the structure may be considered as a transmission path in which fins 13 and slots 11 comprise means for alternately decreasing and increasing the axial electric field at successive intervals along the path.
  • the wave-guiding structure may be considered as a corrugated structure comprising regularly spaced sections having alternately different surge impedances.
  • the hollow interior of block 10 may be considered to be a wave guide comprising regularly spaced sections.
  • the sections at each slot 11 may be considered to have a high surge impedance, while the sections at each fin 13 may be considered to have a low surge impedance.
  • the structure may be considered as being made up of a succession of iterative sections each of length d along the path of electron flow and introducing a phase displacement of [3.
  • Fig, 2 shows schematically such an amplifier in which there is incorporated a ribbon helix wave circuit.
  • the various tube elements are enclosed in an evacuated tubular envelope 61 which preferably is of copper.
  • the electron gun 62 which for purposes of convenience and simplicity in the drawings is shown simply as a cathode emissive surface.
  • the target electrode 63 which defines with the electron gun a longitudinal path of electron flow. Conventional magnetic focussing is employed to minimize radial components of electron flow.
  • the electron source is maintained at a negative beam potential with respect to the envelope by means of the voltage source 70.
  • the wave transmission circuit which in this case comprises the helically wound, or otherwise fashioned, ribbon conductor 64 having its broad dimension extending in the direction of flow.
  • Input waves which are to be amplified are applied by way of the wave guide 66 from a source 66a, shown schematically, coupled downstream along the circuit and output waves which are abstracted upstream along the circuit are derived by way of wave guide 67.
  • One convenient technique for achieving a suitable wave transmission circuit of this kind is to groove a hollow metallic cylinder along a suitable helical path. ln particular, the wave circuit shown is of this construction.
  • the pitch of this grooving determines the wave velocity along the circuit and according ly is adjusted to provide a phase velocity suitable for interaction of the kind being described.
  • Electromagnetic waves are propagated along the circuit in interacting relation with oppositely directed electron flow.
  • the broad dimension of the ribbon helix serves to shield electrons opposite thereto from the longitudinal electric field components of the propagating wave. Only within the gap between turns will the axial electric field of the propagating wave be high. Accordingly, the path of' travel for a particular group of electrons will comprise periodic intervals of high axial field strength interspersed with longer drift regions of low axial field strength in the manner described above.
  • the velocity of the stream is made such that while a charged particle traverses the average distance between turns, the backward traveling wave traverses an integral number of wavelengths less the distance between turns. In this way, a given group of electrons interacts with successive like portions of the wave as it traverses successive gaps between turns.
  • Figs. 3A, 3B, and 3C show schematically a backward wave amplifier 80 which utilizes an interdigital type circuit as representative of a somewhat different form of wave guiding structure.
  • 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 define a longitudinal path of electron flow along the axis of the (tube. This flow can be in the form of a hollow cylindrical electron beam. Magnetic focussing is employed to minimize transverse components of electron flow in the usual manner.
  • Beam accelerating potential is supplied by the voltage supply 90. Electromagnetic waves to be amplified are made to propagate upstream along a slow wave transmission path as before.
  • a loaded wave guide 84 which comprises the portion of the envelope loaded by means of two rows or sets 91 of regularly spaced fins or fingers 92 extending in a linear array in an interdigital pattern from the two opposite broad inner surfaces of the envelope, each row parallel to and on opposite sides of the axis of the tube. Two rows are used to provide two parallel circuits to make more efficient use of the cylindrical electron beam.
  • the lengths of the fins of each row increase at each end gradually towards the center section which comprises a multiplicity of fins of uniform length. This length is suificient to have the fins projecting from one surface of the envelope interleave with the fins projecting from the opposite surface to form longitudinal gaps 93 between fins past which the electrons flow.
  • Input waves are applied to the downstream end of this circuit by way of an input circuit 94 which is a rectangular wave guide which can be a continuation by way of a glass window of a wave guide transmission system which includes a source 94:: of electromagnetic waves, here shown schematically, and output waves are abstracted for utilization at the upstream end of the wave circuit 95 by way of an output circuit which is also a rectangular wave guide.
  • Both the input and output circuits 94 and 95 make a right angle bend with the elongated portion of the tube envelope, and accordingly 45 degree deflection plates 96 are provided at the ends of the loaded guide section 8-4 obliquely across the elongated portion of the envelope diverting input waves for longitudinal travel along the slow wave circuit 84 and amplified output waves to the output circuit 95.
  • These plates are provided with apertures 97 for the passage of electron flow therethrough.
  • the operation is as has been described above.
  • the electron velocity is adjusted so that a particular group of electrons interacts with like portions of the backward traveling wave as it traverses successive gaps between fins where the interacting field component is high. In this case, however, the direction of the longitudinal field in a I v 10 r the gap between fins reverse with each successive gas. This is a characteristic well known for such .interdigital structures which in effect are special forms of folded waveguides.
  • 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 should be adjusted to be substantially equal to 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 wave 1 phase displacement in between successive gaps.
  • each interdigital structure be considered as a plurality of iterative filter sections, each section comprising a pair of adjacent fins and associated gaps
  • the velocity of the electron stream should be 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 6 is the phase displacement per filter section of the wave. It can be seen that this relationship is similar to that derived for the wave circuits shown in Figs. 1 and 2.
  • An amplifier comprising an electron source and target electrode defining a path of unidirectional electron flow, a wave guiding structure for propagating high fre quency waves along said path in a direction opposite to that of electron flow and in interacting relationship with the electrons therein, a source of high frequency waves,
  • a source of electromagnetic waves a wave guiding structure supplied at the input end with waves from said source for propagating therethrough and providing along a longitudinal path periodic gaps of high longitudinal fields separated by longer regions of substantially lower longitudinal fields, output means at the output end of the wave guiding structure for abstracting waves therefrom, and means for projecting a unidirectional electron stream along said path in interacting relationship with electromagnetic waves propagating along said wave guiding structure in a direction opposite to that of propagation of the electromagnetic waves, said input end being at the downstream end of said wave guiding structure and said output end being at the upstream end of said structure.
  • an amplifier In an amplifier, an electron source and a target electrode defining therebetween a path of electron flow, an intermittent interaction type of wave transmission circuit extending along said path for providing therealong periodic intervals of high electric field, a source of electromagnetic waves for applying input electromagnetic waves coupled to the downstream end of the wave transmission circuit, utilization means for abstracting output waves coupled to the upstream end of the wave transmission circuit and flow accelerating means for projecting the electron flow along said path at a velocity substantially equal to and 2n1r ⁇ 3 where w is the angular frequency of the input waves, n is an integer, [3 is the phase difference in radians between the electric fields at two successive like intervals, and a is the distance along said path between the two successive like intervals.
  • an electron source and a target electrode defining therebetween a path of unidirectional electron fiow, a wave guiding structure which comprises a plurality of iterative sections positioned along said path, a source of signal waves, input coupling means at the down stream end of said structure and supplied from said source with signal waves for propagation upstream along said structure in interacting relationship with electrons in said path of flow, and output coupling means at the upstream end of said structure for deriving output wa ves said input and said output coupling means being situated between said electron source and said target electrode.
  • an electron source and a target electrode defining therebetween a path of electron flow, a wave guiding structure positioned along said path for providing therealong periodic intervals of high longitudinal fields separated by longer regions of substantially lower longitudinal fields, input means coupled to the downstream end of the path for applying electromagnetic waves for propagation along said structure, and output means coupled to the upstream end of the path for abstracting electromagnetic waves from the structure and fiow accelerating means for projecting the electron flow along said path at a velocity substantially equal to where w is the angular midband frequency of the propagating wave, n is an integer, ,8 is the phase difference in radians between the electric fields of two successive like intervals of high longitudinal field, and d is the distance along said path between the two successive like intervals.
  • the wave guiding structure is a longitudinal conductor with a plurality of transverse slots.
  • the wave guiding structure is a ribbon helix having its broad dimension parallel to the direction of electron flow.
  • the wave guiding structure is a wave guide loaded by means of an interdigital array of conductive elements.
  • an electron source and a target electrode defining a longitudinal path of unidirectional electron flow, a source of electromagnetic waves, a dispersive wave circuit positioned along said path and supplied from said source for propagating the electromagnetic waves in a direction opposite to that of electron fiow in interacting relationship with electrons therein and providing along said path periodic intervals of high longitudinal electric fields interspersed with drift regions of lower longitudinal electric fields, output means at the upstream end of said circuit for abstracting output waves, said input and said output means being situated between said electron source and said target electrode and beam accelerating means for varying the velocity of electron flow in the direction of forward travel along said path.
  • an electron source and a target electrode defining a longitudinal path of electron flow, a source of a band of electromagnetic waves, a dispersive wave circuit positioned along said path and supplied from said source for propagating the electromagnetic waves in a direction opposite to that of electron flow and providing along the path periodic intervals of high longitudinal field strength interspersed with longer regions of low longitudinal field strength, output coupling means at the upstream end of said circuit for abstracting output waves for utilization, beam accelerating means including voltage supply means for projecting the electron flow along said path at a velocity substantially equal to References Cited in the file of this patent UNITED STATES PATENTS 2,641,731 Lines June 9, 1953 2,653,270 Kompfner Sept. 22, 1953 2,654,047 Clavier Sept.

Landscapes

  • Microwave Tubes (AREA)
US288438A 1950-03-18 1952-05-17 Backward wave amplifier Expired - Lifetime US2916657A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NLAANVRAGE7306318,A NL175617B (nl) 1952-05-17 Werkwijze voor de optische splitsing van racemisch lysinesulfanilaat.
BE520002D BE520002A (de) 1952-05-17
US150429A US2708236A (en) 1950-03-18 1950-03-18 Microwave amplifiers
US288438A US2916657A (en) 1952-05-17 1952-05-17 Backward wave amplifier
FR1068806D FR1068806A (fr) 1952-05-17 1952-09-02 Amplificateur pour ondes rétrogrades
GB13243/53A GB742739A (en) 1950-03-18 1953-05-12 Improvements in or relating to travelling wave amplifiers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US288438A US2916657A (en) 1952-05-17 1952-05-17 Backward wave amplifier

Publications (1)

Publication Number Publication Date
US2916657A true US2916657A (en) 1959-12-08

Family

ID=23107099

Family Applications (1)

Application Number Title Priority Date Filing Date
US288438A Expired - Lifetime US2916657A (en) 1950-03-18 1952-05-17 Backward wave amplifier

Country Status (4)

Country Link
US (1) US2916657A (de)
BE (1) BE520002A (de)
FR (1) FR1068806A (de)
NL (1) NL175617B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3384779A (en) * 1964-07-31 1968-05-21 Gen Electric Co Ltd Collector electrode system for m-type travelling wave tubes
US4706048A (en) * 1984-03-17 1987-11-10 Ernst Leitz Wetzlar Gmbh Wide-band matching network for piezoelectric transducer
EP3392899A4 (de) * 2015-12-18 2019-08-21 Nec Network And Sensor Systems, Ltd. Langsamwellenschaltung und wanderfeldröhre

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR987573A (fr) * 1949-04-05 1951-08-16 Csf Tube à champ magnétique constant pour la production d'ondes cention?riques et millimétriques
US2641731A (en) * 1947-10-06 1953-06-09 English Electric Valve Co Ltd Wave propagating electron discharge device
US2653270A (en) * 1944-06-08 1953-09-22 English Electric Valve Co Ltd High-frequency energy interchange device
US2654047A (en) * 1948-01-20 1953-09-29 Int Standard Electric Corp Beam traveling wave amplifier tube
US2683238A (en) * 1949-06-17 1954-07-06 Bell Telephone Labor Inc Microwave amplifier
US2757311A (en) * 1949-06-02 1956-07-31 Csf Double beam progressive wave tube

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2653270A (en) * 1944-06-08 1953-09-22 English Electric Valve Co Ltd High-frequency energy interchange device
US2641731A (en) * 1947-10-06 1953-06-09 English Electric Valve Co Ltd Wave propagating electron discharge device
US2654047A (en) * 1948-01-20 1953-09-29 Int Standard Electric Corp Beam traveling wave amplifier tube
FR987573A (fr) * 1949-04-05 1951-08-16 Csf Tube à champ magnétique constant pour la production d'ondes cention?riques et millimétriques
US2757311A (en) * 1949-06-02 1956-07-31 Csf Double beam progressive wave tube
US2683238A (en) * 1949-06-17 1954-07-06 Bell Telephone Labor Inc Microwave amplifier

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3384779A (en) * 1964-07-31 1968-05-21 Gen Electric Co Ltd Collector electrode system for m-type travelling wave tubes
US4706048A (en) * 1984-03-17 1987-11-10 Ernst Leitz Wetzlar Gmbh Wide-band matching network for piezoelectric transducer
EP3392899A4 (de) * 2015-12-18 2019-08-21 Nec Network And Sensor Systems, Ltd. Langsamwellenschaltung und wanderfeldröhre
US10483075B2 (en) 2015-12-18 2019-11-19 Nec Network And Sensor Systems, Ltd. Slow wave circuit and traveling wave tube

Also Published As

Publication number Publication date
FR1068806A (fr) 1954-07-01
NL175617B (nl)
BE520002A (de)

Similar Documents

Publication Publication Date Title
US2985790A (en) Backward wave tube
US2801361A (en) High frequency amplifier
US2541843A (en) Electronic tube of the traveling wave type
US2683238A (en) Microwave amplifier
US2881348A (en) Delay line for traveling wave tubes
US2595698A (en) Electron discharge device and associated circuit
US3221205A (en) Traveling-wave tube with trap means for preventing oscillation at unwanted frequencies
US2957103A (en) High power microwave tube
US2888597A (en) Travelling wave oscillator tubes
US2858472A (en) Slow-wave circuit for a traveling wave tube
US2825841A (en) Travelling wave tubes
US2812468A (en) Spatial harmonic traveling wave tube
US2844753A (en) Traveling wave tube
US2708727A (en) Helix coupling arrangements
US2806974A (en) Plasma amplifiers
US3069587A (en) Travelling wave device
US2895071A (en) Traveling wave tube
US2945981A (en) Magnetron-type traveling wave tube
US2806975A (en) Transition from bifilar helix to waveguide for backward wave oscillator
US2843791A (en) Traveling wave tube
US2916657A (en) Backward wave amplifier
US2889487A (en) Traveling-wave tube
US2828439A (en) Space charge amplifier
US3205398A (en) Long-slot coupled wave propagating circuit
US3471738A (en) Periodic slow wave structure