US2925519A - Traveling wave tube - Google Patents

Traveling wave tube Download PDF

Info

Publication number
US2925519A
US2925519A US452247A US45224754A US2925519A US 2925519 A US2925519 A US 2925519A US 452247 A US452247 A US 452247A US 45224754 A US45224754 A US 45224754A US 2925519 A US2925519 A US 2925519A
Authority
US
United States
Prior art keywords
wave
focusing
electrons
circuit
electron
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
US452247A
Other languages
English (en)
Inventor
Cassius C Cutler
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 NL198576D priority Critical patent/NL198576A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US452247A priority patent/US2925519A/en
Priority claimed from US452248A external-priority patent/US2925520A/en
Application granted granted Critical
Publication of US2925519A publication Critical patent/US2925519A/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
    • H01J25/38—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 forward travelling wave being utilised

Definitions

  • FIG. 4 A T TORNE V Feb. 16, 1960 c. c. CUTLER TRAVELING WAVE TUBE 5 Sheets-Sheet 3 Filed Aug. 26. 1954 FIG 3 k EWQQDU 06k UN 40b Irv FIG. 4
  • This invention relates to devices which utilize the interaction between an electron beam and a traveling electromagnetic wave over a distance equal to a plurality of operating wavelengths.
  • Such devices are now commonly described as traveling wave tubes and have heretofore been characterized by decreasing efficiency at high signal levels.
  • the electron Stream In a traveling wave tube, the electron Stream is projected closely past an interaction circuit along which the signal wave is propagating. For efficient operation, it is generally important to keep the electron flow cylindrical (i.e., to have no net divergence or convergence) both to avoid having electrons strike the interaction circuit and to confine the electrons to regions of high signal fields. To minimize the space charge transverse components of force upon the electrons within the beam, it is the usual practice to set up a uniform longitudinal magnetic'field along the path of electron flow. This magnetic field has generally been achieved by the use of either permanent magnets or solenoidal magnets external of the tube.
  • the usual manner for achieving such a uniform longitudinal field has been to employ Brillouin type focusing .with high density electron beams.
  • the electron gun is enclosed in a magnetic shield, and the electrons are caused to spiral as they enter the region of longitudinal magnetic field from the shielded region.
  • the angular velocity of each electron is proportional to the dilference in magnetic flux encountered in going from the shielded region into the field region.
  • the inward or focusing force per charge is proportional to the product of the angular velocity and the longitudinal magnetic field, or, effectively, the square of the magnetic field.
  • This inward force is adjusted to counterbalance exactly the sum of the mutually repulsive outward forces of the electrons (generally described as the space charge forces) and the outward centrifugal force of the spiraling electrons. If, in addition to satisfying this condition along the magnetic field region, the electron beam is caused to enter the magnetic field region initially with zero radial velocity, it will travel without spreading down the length of the tube, to be collected by a collector electrode at the far endof the tube.
  • an electromagnetic wave is introduced into the wave propagating circuit which is contiguous to the electron beam along the length of the tube in a manner such that there is a component of electric field of the wave which is parallel to the electron beam, interaction between the wave and the beam will take place.
  • Such interaction takes the form both of extraction of energy from the electron beam by the wave, and extraction of energy from the wave by the beam.
  • the energy extracted from the wave by the beam will serve to accelerate some of the electrons in the beam, while the extraction of energy from the beam by the wave results in a deceleration of some of the electrons in the beam.
  • This interaction thus superimposes on the D.-C. velocity of the beam an A.-C. velocity component and results in bunches in the beam of high electron density interposed between regions of low electron density.
  • this A.-C. velocity component still exists, but the average velocity of the beam is decreased as a natural result of the net loss of energy from the beam.
  • traveling wave tube xhibit the phenomenon of overloading, that is, with an increase in input level of the wave the output of the tube increases substantially linearly up to a point, and then begins to level oif until another point is reached where a further increase in input level gives no further increase in output. This latter point is the overload point of the tube.
  • a further increase in input level results in an actual decrease .in output.
  • the eificiency of a traveling wave tube reaches a maximum as the overload region is approached, and beyond the overload region, the efiiciency decreases.
  • a succession of magnetic pole pieces are spaced uniformly along the major portion of the length of the'tube and are joined together by permanent magnets in a manner such that alternate pole pieces will be of opposite polarity.
  • Such an arrangement has the effect of imparting a uniform periodicity to. the magnetic focusing field.
  • the strength of each successive focusing region is made to differ from adjacent focusing regions by using permanent magnets of diflierent strength.
  • the velocity of propagation characteristic of the traveling wavecircuit is made to change in a particular manner along the length of the tube.
  • Fig. l is a series of curves pictorially representing the behavior of electrons in the beam for various levels of signal;
  • Fig. 2 is a sectional view of a traveling embodying my invention
  • Fig. 3 is a plot of collector current versus the focusing parameters in a periodic focus traveling wave tube, showing the higher order pass and stop bands
  • Fig. 4 is a sectional view ofanother focusing arrangement for a traveling wave tube embodying my invention
  • Fig. 5 is a sectional view of still another tube embodying my invention.
  • FIG. 6 is asectional view of a tube embodying my invention wherein electrostatic focusing is used, and;
  • FIG. 7 is a view showing the connection of the plates to the walls of the tube of Pig. 6.
  • Figure 1(a) represents the voltagewave in the wave propagating circuit, which, for simplicitys sake, is shown as sinusoidal. If this wave corresponds to a low level input signal, and a beam of electrons is directed along the wave propagation circuit for interaction with the wave, at regions well along the wave circuit a velocity modulation of electrons within the beam takes place.
  • This velocity modulation is pictured in Fig. 1(b), wherein the ordinate represents velocity, and the abscissa represents phase.
  • the origin on the ordinate scale represents the average or D.-C. velocity of the electron beam.
  • the curve of Fig. 1(b) represents the distribution of electrons within the beam relative to the phase of the traveling wave, and the velocities of the'electrons at any given phase angle.
  • the first bunch being in phase with the wave and the ..s econd bunch having fallen back in phase'until' its phase relationship with the wave is such frointhe wave.
  • the reason for the leveling off of the gain at overload can now be understood.
  • the electrons in the second bunch are in a position to absorb energy from the wave as quickly as energy is given up to the wave by electrons in the first bunch. In addition, this absorption of energy from the wave acts to reduce the velocity of the wave and decrease lts amplitude until UL; um Grotlaunch.
  • Fig. 1(a) represents the velocity distribution in the beam for a signal of input level beyond overload.
  • the electrons in the second bunch which absorbenergy from he wave, commence to speed up, and hence advance in phase. However, a portion of the electrons in this bunch, because of the repulsion effect of space charge forces, continue to fall back in phase relative to the wave. It can be seen by a study of Figs. 1(a) through 1(a) that for a signal of any input level, there is a large group of electrons which stays in the proper phase relationship with the traveling wave for giving up energy to the wave.
  • the present invention achieves these ends by eliminating or expelling from the electron beam the slow electrons which tend to form these secondary groups before the groups are formed, with the net result both that the only electrons remaining in the beam are those which will continue to transfer energy to the wave and that there will be substantially no extraction of energy from the wave by secondary groups.
  • Such focusing action is preferably obtained by the use of an arrangement which provides a succession of alternately stronger and weaker fociuing regions.
  • Such a succession of alternately stronger" and weaker focusing regions may be advantageously achieved by use ofperiodic focusing.
  • a detailed description'and analysis of magnetic periodic focusing may be found in the copending applications of I. R. Pierce, Ser. No. 351,983, filed April 29, 1953, now United States Patent 2,847,607, issued August 12, 1958, and Ser. No. 351,984, filed April 29, l953, now United StatesPatent 2,841,739, issued July 1, 1958.
  • a brief description of this'type of focusing will be given here to facilitate an understanding of the present invention.
  • the succession of focusing fields may be regarded as a series ofthin converging lenses. If the beam is started in such a manner that it is cylindrical midway between two adjacent lenses, and if the lenses are chosen of the right strength, the fiow will be cylindrical between the next two lenses.
  • Converging effect of the lenses is on the average just balanced out by the diverging effect of the space between the lenses, and the electron beam flow is identical between each pair'of lenses. 1
  • sufiiceint may be completely expelled i from the beam.
  • This difference in behavior of electrons within the beam under the influence of aperiodic magnetic field gives rise to .pass bands, that is, for a given magnetic field a range of velocitieswhere the elec trons will be focused, and stop bands, where, for the some magnetic field, there is a range of velocities where the electrons will be defocused.
  • the present invention makes use of this phenomenon, in a manner which will be more fully explained hereinafter, to eliminate from the electron beam those electrons in the beam which have fallen back inphase from the group of electrons which are giving up their energy to the wave, thus preventing them from extracting energy from the wave. Moreover, the elimination of these electrons from the beam makes possible the, realization of the advantages to be gained from varying the propagation characteristic of the wave circuit to maintainsym.
  • Fig. 2 there is illustratedschemati cally a traveling wave tube 11 embodying the principles of the invention.
  • a source of a solid beam of electrons 13 Located at opposite ends of an evacu- 'ated elongated envelope 12 which, for example,is of glass or any suitable non-magnetic material, or of magnetic materialwhich will saturatereadily, are a source of a solid beam of electrons 13 and a target or collector electrode 14.
  • the electron source 13 is shown schematically and will, in general, consist of an electron emissive cathode, a heater unit, an intensity control element, and an electrode, arrangement 15 for shaping and accelerating the beam.
  • the target 14 serves as a collector of electrons and is, accordingly, maintained at a suitable potential positive with respect to the electron emissive cathode of the source 13 by means of suitable lead in connections from a voltage source, not here shown.
  • an elec- I trode member maintained at a positive potential with respect to the cathode of the source is disposed along the path of flow for providing an accelerating field.
  • the interaction circuit itself serves as such an electrode.
  • the interaction circuit comprises a helically coiled conductor 16, a plurality of operating wavelengths long, which serves as a propagating circuit for electromagentic waves.
  • the pitch of the helix determines the velocity with which the wave propagates down the length of the tube, and this pitch is adjusted to propagate the wave in coupling relationship with the electron beam, In addition, the.
  • helical interaction circuit 16 serves as an accelerating electrode for the electron beam and so is maintained at a suitably positive potential with respect to the cathode of theel-ectron gun.
  • the helix. 1a is connected to an external transmission line by suitable coupling.
  • the coupling means comprises the helix 13 wound in a'sense opposite to that of the helix 16 and surrounding the tube envelope along a region overlapping the input end of the helix 16.
  • the end of the helix 17 adjacent the end of the helix 16 is connected to the inner conductor of the coaxial line 17A which forms the'external transmission line leadingto the signal source and its opposite end is terminated to besubstantially reflectionless. Coupled helix arrangements of this kind are described more fully in copending application Serial No. 360,579, filed June 9, 1953, byR. Kompfner, now United States Patent 2,834,908, issued May 13,1958.
  • a series of bar magnets ll is disposed across successive gaps between the pole pieces, the magnets across adjacent gaps being reversed in sense whereby there results along the path of electron flow a succession of regions of longitudinal magnetic fields, the direction of the magnetic fields reversing with each successive region.
  • each suc ceeding region of magnetic field is made weaker than the preceding region over an output end portion of the path of flow. This is accomplished by using pro-gressive ly Weaker bar magnets 21. r This is illustrated here by depicting successive magnets along the output end portion as of increasingly smaller cross-section.
  • suitable electrodes plac ed along the tube for that purpose. If a periodic focus traveling wave tube is operated with the values of 13 L and v such that the major portion of the in-phase electrons, which have velocities approximating v are focused to the extent indicated at point Y, and the signal input level is in the overload region, those electrons at the rear of the first bunch of electrons, which are decelerated as shown and explained in conjunction with Fig. 1(d), fall within the stop band Y-Y". Thus those electrons to which is attributed the overload behavior are defocused and expelled from the beam.
  • the operating point Y is so chosen that either the tendency of the electrons to form a tai as overload is approached is prevented in its inception, or the tail is allowed to form to some extent so that the last measure of utility had from those electrons, but the formation of the second group of electrons is prevented by defocusing the electons as their velocity decreases to within a certain range.
  • the first group of electrons which is advantageously phased with the wave, moves down the tube toward the collector, the velocity of the electrons within the group gradually decreases as they give up their energy to the wave, with the result that these electrons tend to approach a stop band, i.e., point Y shifts to the right in Fig. 3.
  • the electrons toward the rear of the bunch have a still greater decreased velocity, due to the space chargeeffects 'as discussed earlier, and hence they approach a pass band (Y"Y"'). If these tendencies-are allowed to go unchecked, there occurs at some point along the flow path a defocusing of the desirable electrons and a focusing of the undesirable ones.
  • the present invention corrects these tendencies by varying at least one of p the three focusing parameters with progress along the path of .flow in a manner to maintain the operating point of the system continually in a fixed position relative to the stop and pass bands, so that the properly phased electrons remain focused throughout their travel down the tube while the improperly phased electrons become defocused.
  • the strength of the magnetic field is decreased in each succeeding focuslllglglGfl, while the spacing of the fields is maintained constant.
  • the decreased strength may be simply achieved by decreasing the cross section of each succeeding magnet, or alternatively, it may be achieved by decreasing the magnetization of each succeeding magnet.
  • the net effect is to keep the operating polnt for the undesirable electrons within a stop band throughout the interaction length of the tube.
  • the amount of change in magnetic field necessary for this purpose varies in greater or lesser degree depending upon such things as deam density and radius which determine the space charge forces.
  • the wave and the beam are maintained in coupling relation along substantially the entire length of the wave circuit by imparting to the output end portion of the wave circuit a decreasing velocity characteristic with progress towards the output end.
  • the helical interaction circuit is varied in pitch along the output end of the tube, the pitch decreasing toward'the output end. .Since the propagation characteristic of the circuit varies as the pitch, a decrease in pitch results in a decrease in the velocity of a wave propagating along the circuit.
  • the wave is made to stay in proper phase relationship with the'beam asthe beam decreases in average velocity.
  • the magnetic focusing fields are created by permanent magnets.
  • Other means such as solenoidal' magnetic means, may be used in place of the permanent magnets, in which case the control over the strength of the magnetic focusing fields is maintained by controlling the current ineach winding or solenoid or the number of effective turns in each solenoid, or both.
  • Such an arrangement is'within the scope of the present invention, as are other arrangements of similar nature.
  • Fig. 4 there is illustrated a short section of the interaction path of a tube embodying these principles. plicitys sake, the elements in Fig. 4 which are the same as elements in Fig. 2 are designatedby the same reference numerals.
  • the strength'of the magnets is made to increase along a downstreamportion' of the length of the tube with'distance toward theoutput end to give a periodic focusing arrangement of gradually in- The spacing between each of 'the focusing regions is decreased toward the output end sufficiently to maintain the proper stop and pass band positioning as explained in the foregoing.
  • Fig. 5 is shown an embodiment of the principles of the invention wherein the*variations in the focusing effect are introduced inthe tube near the output .end only.
  • a traveling wave tube 31 having an elongated evacuated envelope 32, atopposite ends ofwhich are located an electron beam source 33 and a target or collector electrode 34.”
  • the electron beam source 33 has associated therewithan electrode arrangement 35 for shaping the electron beam.
  • a helically coiled conductor 36 serves as the'wave propagating circuitand iscoupled at its ends to an impedance matching input coupler 37 and an impedance matching output coupler 38 which may take any one of a number of suitable forms including the coupling arrangements mentioned in connection with Fig.
  • a longitudinal magnetic focusing field is supplied by a magnetic member 39 which may be a permanent magnet or a solenoid arrangement, and which has'mounted at its ends pole pieces 41 and 42 of suitable magnetic material. Disposed along the path of flow, toward the output end of the tube is a series of cylindrical rings 43 of magnetic material which surround the helix 36. These rings 43 of magnetic material act as shunts for the magnetic field, and hence have the effect of imparting to the field periodic non-uniformities.
  • electric lines bfforce are setup between successive electrodes disposed along the beam path, successive electrodes 'being of opposite polarity with respect to the mean potential between adjacent electrodes.
  • variations, in the potential difference between adjacent electrodes and variations in the spacing of the electrodes causefithefocusing regions' toaot'upon the beam in the same or similarmanner-that variations in the magneticfield strength and in the periodicity of the magnetic.
  • focusing .regions act upon the beam in a magnetic focusing arrangement.
  • Tube 51 comprises a wave guiding circuit 52 whichis, for example, a hollow wave guide-of rectangular cross section which is folded back and-forth upon itself in serpentine fashion, in the manner shown and described inthe copending United States patent 'application Serial 250,093, filed October S6, 1951; of C. C5 Cutler, Know. United StatesPatent 2,8lO;85 4,"issuedOctober 22, 1957. Wave energy .is
  • wave energy is extracted from the tube at the output end 54 througli'a similar connection to a conventional rectangular zvave guide.
  • a source,, 55 of an electron beam is .,located jadjacent the input end of the-wave circuit and orientedto direct anelectron stream along the tube transversely of the folds in the wave guide.
  • Thesour ceSS is shown schematically and may ing from opposite walls 59fnad 61, respectively, in an interdigital pattern.
  • the walls 59 and 6 1 are of conducting material.
  • Each -of the plates 57, 57 is capacitively connected/to the .wall 59 by a condenser 62 and each of the plates 58, 58 is capacitively connected to the wall 61 by.
  • the capacitive connection makes possible D.-C. isolation of the various plates so that different voltages may be applied to suecessive plates toachieve electrostatic focusing.
  • the capacitive connections 62and 163. may be made in any suitable way, such as, for example, by the structure shown in Fig.7, wherein each plate 57 is separated from the wall 59 by a suitable dielectric material 64, such as mica. radio frequency propertiespf the wave circuit are undividing resistor 66 supply the necessary potentials for the plates to permit passage of the beam through the plates and the regions between. t
  • the plates 57, 57 and 58, 58 are maintained at progressively decreasing potentials toward the output end over the last portion of the circuit to counteract the effects of the decreasing electron velocity, thus maintaining the operating point of the beam in proper.relationshipwith the stop and pass bands in' accordance with the principles of the invention asset forth.- t l
  • the decreasing electron velocity makes necessary a gradual decrease in. the wave velocity from input to output In the embodiment of Fig.6, the path length of the wave propagation. circuit isincreased by making successive plates 57 and 58 longer than the preceding ones, thus effectively slowing down the wave by causing it to traverse longer transverse paths for given increments of axial travel downthetube. 1
  • An electron discharge device comprising a slow wave circuit and an electron beam source for projecting an electron beam along said slowwave circuit in coupling relation thereto for cumulative interaction with a high frequency wave propagating on said circuit, the interaction resulting in electrons in the beam becoming improperly phased for cumulative interaction with the wave over at least a portion of the length of the slow wave circuit in the region of interaction and in a net slowing down of the beam, means for defocusing the improperly phased electrons despite changes in the net beam velocity comprising means disposed along the path of electron flcw for atleast a portion thereof for establishing a succession of dissimilar, spaced focusing regions therealong, the product of the focusing field strength within the regions and'the spacing of the regions decreasing over a distance of at least threelsuccessive regions in the direction of beam travel.
  • said slow wave circuit having a nonuniform propagation characteristic for maintaining the wave and the beam in synchronism along that portion or; the slow wave circuit where the interaction takes place.
  • An electron discharge device comprising a slow wave circuit and an electron beam source for projecting anelectron beam along said slow wave circuit in coupling relation thereto for cumulative interaction with a high frequency wave propagating on said circuit, the interaction resulting in electrons in the beam becoming improperly phased for cumulati e interaction with the wave oyer atleast a portion of the length of the slow wave circuitjin the region of interaction and in anet' slowing down of the beam, meansfor defocusing the improperly phased, electrons despite changes in the net beam velocity comorising a plurality of means dis osed along the path of electr on how for at least a portion thereof for establishing a succession of spaced focusing regions'therealongg 'the' spacing between successive ones of said means being difierent whereby impro erly phased electrons are defocusei-the spacing decreasing over a distance of at least thiee successive regions in the direction of beam travel] 1 f I s t s 3.
  • An"electronfdischarge device comprising a slow wave circuit and an electronbeam source for projecting an electron beam along said slow wave circuit in coujplingrelation thereto for cumulative interaction with a high frequency wave propagating'on said circuit, the interaction resulting inelectrons in the beam becoming improperly phase for cumulativeinteraction with the wave over at least a portion of the length 'of the slow wa e circuit in the region of interaction and in a net slowing down of the beam, means fordefocusing the improperly phased electrons despite'changes'in the net bea'm yelocity comprising a plurality of means disposed along the path of electron how for at least a portion thereof for establishing a succession of spaced focusing [regions therealong, 'thejlspa'cing'between successive ones 'of said means being different whereby improperly phased electrons are defocused, the spacing decreasing over a distance of at least three successive regions in the direc- 'tionof beam travel, said slow wave circuit having a nonuniform
  • ⁇ .”Anelectron discharge device comprising a slow "wave'circuit and an electron'bearn source for projecting an electron beam alongsaid slow wave circuit in conpling relation thereto for. cumulative interaction with a high frequency wave propagating on said circuit
  • improperly phased electrons beam velocity comprising means of electron fiow for at least a portion thereof for establishing a succession of spaced focusing regions therealong, the magnitude of the focusing fields in each focusing region being different from the others whereby improperly phased electrons are defocused, the magnitude of said fields decreasing over at least three successive regions in the direction of beam travel.
  • An electron discharge device comprising a slow wave circuit and an electron beam source for projecting an electron beam along said slow wave circuit in coupling relation thereto for cumulative interaction with a high frequency wave propagating on said circuit, theinterr action resulting in electrons in the beam becoming 1m:
  • means for defocusing the improperly phased electrons despite changes in the net beam velocity comprising means disposed along the path of electron flow for at least a portion thereof for establishing a suewave circuit and an electron .beam source for projecting an electron beam along said slow wave circuit in coupling relation thereto for cumulative interaction with a high frequency wave propagating on said circuit, the interaction resulting from the electron beam becoming improperly phased for cumulative interaction with the wave over at least a portion of the length of the slow wave circuit in the region of interaction and in a net slowing down of the beam, means for defocusing the improperly phased electrons despite changes in the net beam velocity comp-rising a plurality of means disposed along the path of electron flow for at least a portion thereof for establishing a succession of spaced focusing regions there along, the spacing between successiveones of said means being different, the spacing decreasing over at least three successive
  • An electron discharge device comprising a slow wave circuit and an electron beam source for projecting an electron beam along said slow wave circuit in coupling lishing asuccession of spaced focusing regions therealong, the spacing between successive ones 'of said means;being different, the spacing decreasing over atvle'ast three suc- Y c'essive regions: in the direction of bearn travel,. and ,the
  • An electronic device comprising, in combination, means .mcludingan'electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between saidgun and collector, input coupling means coupled to said circuit at one end thereof, output coupling means coupled to .said circuit at the other end thereof, and means for establishing dissimilar spaced focusing regions alongat least a portion of the path of electron flow, the focusing effect of said focusing regions being governed in part bythe parameters B and L, where B is a measure-of thestrength of the focusing fields and L is a measure of the'spacing of the spaced regions, said means comprising a plurality of spaced means, successive spaced means being related to vary at least one of the parameters B -and L along at least a portion of the path of electron flow over three or more successive ones of said focusing regions such that the product of B and L decreases in the direction. of electron flow.
  • An electronic device comprising, in combination, means including an electron gun anda collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and said collector, said circuit having a nonuniform propagation characteristic, input coupling means coupledto said circuit at one end thereof, output coup-ling means coupled to said circuit at the other end thereof, and means for establishing dissimilar spaced focusing regions along at leasta portion of the path of electron flow, the focusing effect of said focusing regions being governed in part by the parameters B and L, where B is a measure of the strength of the focusing fields and L is a measure of the spacing of the spaced regions, said means comprising a plurality of spaced means, successive spaced means being related to vary at least one of the parameters B and L along at least a portion of the path of electron flow over three or more successive ones of said focusing regions such that the product of B and L decreases in the direction of electron flow.
  • An electronic device as claimed in claim 9 in which the strength of the focusing fields established by the plurality of means varies over at least a portion of the path of electron flow.
  • the means comprises electrodes for establishing periodic electrostatic focusing regions.
  • a traveling wave tube amplifier comprising, in combination, means including an electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and and said collector, input coupling means coupled to sa d circuit adjacent the electron gun, output couplingrmeans" coupled to said circuit adjacent the collector, and means for focusing the electron beam comprising a plurality of differently spaced elements establishing a seriesof elements decreasing in the direction of beam travel. and causing a predetermined difference in the focusing effect of the focusing regions, the spacing between any pair of adjacent elements being greater than the spacing between the succeeding pair of adjacent elements in the direction of beam travel.
  • collector input coupling means coupled to said circuit adjacent the electron gun, output coupling means coupled to said circuit adjacent the collector, and means for establishing a series of focusing regions of varied strength extending axially of the tube for at least a portion thereof for focusing the electron 'beam, said means comprising a plurality of equally spaced elements, the difference in strength of the several focusing regions decreasing in the direction of beam travel in such a manner that both adjacent and alternate ones of said focusing regions are of different strength causing a predetermined difference in the focusing effect of the focusing regions.
  • a traveling wave tube amplifier as claimed in claim 19 in which the means for focusing the electron beam comprises a plurality of electrodes establishing a series of electrostatic focusing regions.
  • a traveling wave tube amplifier comprising, in combination, means including an electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and said collector, input coupling means coupled to said circuit adjacent the electron gun, output coupling means coupled to said circuit adjacent the collector, and means for focusing the electron beam comprising a plurality of equally spaced elements of different sizes establishing a series of dissimilar focusing regions extending axially of the tube for at least a portion thereof, alternate ones of saidelements decreasing in size toward the collector electrode, the difference in size of the several elements causing a predetermined difference in the focusing effect of the focusing regions.
  • An electron discharge device as claimed in claim 1 wherein said means for defocusing improperly phased electrons comprises a plurality of spaced magnetic shunt rings extending axially of the tube for at least a portion thereof establishing a series of periodic focusing regions each of said shunt rings differing in width from the others whereby there is established a predetermined difference in the focusing effect of the focusing regions.
  • a traveling wave tube amplifier comprising, in combination, means including an electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and said collector, input coupling means coupled to said circuit adjacent the electron gun, output coupling means coupled to said circuit adjacent the collector, means for focusing the electron beam comprising a plurality of differently spaced elements establishinga series of focusing regions extending axially of the tube for at least a portion thereof the difference in spacing between the elements decreasing in the direction of beam travel in such a manner that the spacing between any pair of adjacent elements is greater than the spacing between the succeeding pair of adjacent elements in the direction of beam travel causing a predetermined difference in the focusing effect of the focusing regions, and an interaction circuit for propagating a traveling wave having a the 'wave and the beam in'synchronism along the interaction circuit;
  • a traveling wave tube amplifier comprising, in combination, means including an electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and said collector, input coupling means coupled to said circuit adjacent the electron gun, output coupling means coupled'to said circuit adjacent the collector, means for establishing a series of focusing regions of varied strength extending axially of the tube for at least a portion thereof for focusing the electron beam comprising a plurality of equally spaced elements, the difierence in strength of the several regions causing a predetermined difierence in the focusing effect thereof, the strength of alternate ones of the several regions decreasing toward the output coupling means, and an interaction circuit for propagating a traveling wave having a nonuniform propagation characteristic for maintaining the wave and the beam in synchronism along the interaction circuit.
  • a traveling wave tube amplifier comprising, in combination, means including an electron gun and a collector electrode for forming and projecting an electron beam, a wave propagation circuit between said gun and said collector, input coupling means coupled to said circuit adjacent the electron gun, output coupling means coupled to said circuit adjacent the collector, means for focusing the electron beam comprising a plurality of series of dissimilar fo'cusing'r r at'lea'st a'portion said elements decreasing electrode, the differenqe' 'i causing a predetermined'fdi of the focusing regions, an
  • the tube fo propagating a'traveling wave gation characteristic for maintaining the wave and the beam in synchronism along the interaction circuit.

Landscapes

  • Microwave Tubes (AREA)
US452247A 1954-08-26 1954-08-26 Traveling wave tube Expired - Lifetime US2925519A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL198576D NL198576A (xx) 1954-08-26
US452247A US2925519A (en) 1954-08-26 1954-08-26 Traveling wave tube

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US452248A US2925520A (en) 1954-08-26 1954-08-26 Traveling wave tube
US452247A US2925519A (en) 1954-08-26 1954-08-26 Traveling wave tube

Publications (1)

Publication Number Publication Date
US2925519A true US2925519A (en) 1960-02-16

Family

ID=27036715

Family Applications (1)

Application Number Title Priority Date Filing Date
US452247A Expired - Lifetime US2925519A (en) 1954-08-26 1954-08-26 Traveling wave tube

Country Status (2)

Country Link
US (1) US2925519A (xx)
NL (1) NL198576A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2965782A (en) * 1958-03-12 1960-12-20 English Electric Valve Co Ltd Magnetic focusing systems for travelling wave tubes
EP0037309B1 (fr) * 1980-04-01 1983-12-28 Thomson-Csf Tube à ondes progressives à cavités couplées et focalisation par aimants permanents alternés, et ensemble amplificateur comprenant un tel tube

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200039A (en) * 1937-11-01 1940-05-07 Emi Ltd Permanent magnet device for producing axially symmetrical magnetic fields
US2233264A (en) * 1938-12-27 1941-02-25 Rca Corp Electron lens
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2305884A (en) * 1940-07-13 1942-12-22 Int Standard Electric Corp Electron beam concentrating system
US2369796A (en) * 1943-03-26 1945-02-20 Rca Corp Electron lens system
US2458167A (en) * 1944-04-27 1949-01-04 Machlett Lab Inc Electrical discharge device having cavity resonators
US2653271A (en) * 1949-02-05 1953-09-22 Sperry Corp High-frequency apparatus
FR1080230A (fr) * 1952-07-01 1954-12-07 Philips Nv Dispositif de concentration magnétique pour faisceaux électroniques
US2730648A (en) * 1949-02-04 1956-01-10 Csf Travelling-wave tube
US2741718A (en) * 1953-03-10 1956-04-10 Sperry Rand Corp High frequency apparatus
US2776389A (en) * 1950-11-01 1957-01-01 Rca Corp Electron beam tubes
US2843788A (en) * 1952-12-03 1958-07-15 Rolf W Peter Electron beam tube

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200039A (en) * 1937-11-01 1940-05-07 Emi Ltd Permanent magnet device for producing axially symmetrical magnetic fields
US2233264A (en) * 1938-12-27 1941-02-25 Rca Corp Electron lens
US2300052A (en) * 1940-05-04 1942-10-27 Rca Corp Electron discharge device system
US2305884A (en) * 1940-07-13 1942-12-22 Int Standard Electric Corp Electron beam concentrating system
US2369796A (en) * 1943-03-26 1945-02-20 Rca Corp Electron lens system
US2458167A (en) * 1944-04-27 1949-01-04 Machlett Lab Inc Electrical discharge device having cavity resonators
US2730648A (en) * 1949-02-04 1956-01-10 Csf Travelling-wave tube
US2653271A (en) * 1949-02-05 1953-09-22 Sperry Corp High-frequency apparatus
US2776389A (en) * 1950-11-01 1957-01-01 Rca Corp Electron beam tubes
FR1080230A (fr) * 1952-07-01 1954-12-07 Philips Nv Dispositif de concentration magnétique pour faisceaux électroniques
US2843788A (en) * 1952-12-03 1958-07-15 Rolf W Peter Electron beam tube
US2741718A (en) * 1953-03-10 1956-04-10 Sperry Rand Corp High frequency apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2965782A (en) * 1958-03-12 1960-12-20 English Electric Valve Co Ltd Magnetic focusing systems for travelling wave tubes
EP0037309B1 (fr) * 1980-04-01 1983-12-28 Thomson-Csf Tube à ondes progressives à cavités couplées et focalisation par aimants permanents alternés, et ensemble amplificateur comprenant un tel tube

Also Published As

Publication number Publication date
NL198576A (xx)

Similar Documents

Publication Publication Date Title
US2687777A (en) Thermionic tube for ultrashort waves
US2812467A (en) Electron beam system
US2741718A (en) High frequency apparatus
US2630544A (en) Traveling wave electronic tube
US2424965A (en) High-frequency amplifier and oscillator
US2867745A (en) Periodic magnetic focusing system
US2289220A (en) Electron discharge device
GB654386A (en) Improvements in or relating to high frequency electronic discharge devices
US2858472A (en) Slow-wave circuit for a traveling wave tube
US2849643A (en) Double beam electron discharge tube
US2925519A (en) Traveling wave tube
US2638561A (en) Cathode-ray oscillator tube
US2806974A (en) Plasma amplifiers
US2974252A (en) Low noise amplifier
US2757311A (en) Double beam progressive wave tube
US2800602A (en) Low noise electron discharge tubes
US2888596A (en) Traveling wave tubes
US2641730A (en) Velocity modulation amplifier tube
US2860280A (en) Electric discharge device and methods
US2925520A (en) Traveling wave tube
US2945981A (en) Magnetron-type traveling wave tube
US2794146A (en) Ultra-high frequency amplifying tube
US3265925A (en) Field perturbing means for preventing beam scalloping in reversed field focusing system
US3252104A (en) D.c. quadrupole structure for parametric amplifier
US3758811A (en) Traveling wave tube linearity characteristics