US3068432A - Ladder type delay line - Google Patents

Ladder type delay line Download PDF

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Publication number
US3068432A
US3068432A US838813A US83881359A US3068432A US 3068432 A US3068432 A US 3068432A US 838813 A US838813 A US 838813A US 83881359 A US83881359 A US 83881359A US 3068432 A US3068432 A US 3068432A
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United States
Prior art keywords
rungs
delay line
line
lateral members
ladder type
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Expired - Lifetime
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US838813A
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English (en)
Inventor
Dohler Oscar
Epsztein Bernard
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Thales SA
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CSF Compagnie Generale de Telegraphie sans Fil SA
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Publication date
Priority to FR1068673D priority Critical patent/FR1068673A/fr
Priority claimed from US356050A external-priority patent/US2920227A/en
Priority to US356050A priority patent/US2920227A/en
Priority to DEC11647A priority patent/DE963896C/de
Priority to DEC7802A priority patent/DE953269C/de
Priority to GB17972/53A priority patent/GB761768A/en
Priority to GB33619/55A priority patent/GB761850A/en
Priority to FR64659D priority patent/FR64659E/fr
Priority to DEC9754A priority patent/DE961551C/de
Application filed by CSF Compagnie Generale de Telegraphie sans Fil SA filed Critical CSF Compagnie Generale de Telegraphie sans Fil SA
Priority to US838813A priority patent/US3068432A/en
Publication of US3068432A publication Critical patent/US3068432A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/16—Circuit elements, having distributed capacitance and inductance, structurally associated with the tube and interacting with the discharge
    • H01J23/24—Slow-wave structures, e.g. delay systems

Definitions

  • the present invention relates to delay lines of the ladder type, more particularly for use in traveling wave tubes and magnetrons. This application is a division of application Serial No. 356,050, filed May 19, 1953, nowPatent No. 2,920,227.
  • the present invention relates to a very particular type of delay line for use in electron discharge tubes operating by interaction between the energies contained respectively in the electron beam and in the field of an ultra high frequency wave propagated along the line, as for example in traveling wave tubes.
  • This type of delay line is constructed in the form of a ladder comprising two parallel longitudinal lateral members and a series of par allel rungs extended between the two lateral members, and a metallic base plate upon which the lateral members are supported with the rungs spaced from the base plate.
  • the length of the rungs is approximately equal to half the operating wave length, and from this point of view the ladder type delay line operates more efiiciently than the other known types of delay line such as interdigital or bafile lines.
  • the defect of these other types of line lies in the fact that the width of the line is only a quarter wave length or even less. Consequently, for equal length the ladder line may be used in a tube the electron beam of which is very much wider and the beam current of which is more intense, whereby the tube can supply a greater power. Furthermore, the coupling resistance between the wave and the beam is high with consequent favorable influence on the gain of the tube.
  • the present invention has for its purpose to improve the known delay lines of ladder type, the primary object being to increase the band width and permit propagation of energy within a wide band of frequencies independently of irregularities in the construction of the line.
  • the principal feature of the present invention is the provision of means for tightening up the coupling between the individual circuits constituting the delay line.
  • a laddertype delay line for use in microwave tubes, operating by interaction between the beam of electrons and an ultrahigh frequency wave traveling through the delay line,
  • means are provided for tightening the coupling between the successive circuits of the line, by suppressing, or at least considerably reducing, the magnetic coupling between said circuits, characterised in that the rungs are divided into two sets, even and odd, the rungs of at least one set having their ends bent at right angles to the central portions of these rungs, said ends being secured to a surface different from the surface to which are secured the ends of the rungs of the other set.
  • the magnetic coupling may be reduced to a small value with respect to the electrical coupling by constructing the delay line such that the mean path followed by microwave current between extremities of adjacent rungs on the same side of the delay line is increased with respect to the direct rectilinear path between said extremities.
  • FIGURE 1 is a perspective view of a known delay line of ladder type
  • FIGURE 2 is a diagrammatic representation of a chain of circuits constituting a delay line of the type shown in FIGURE 1;
  • FIGURES 3 to 5 illustrate three forms of the invention wherein means are provided for reducing the electrical coupling of a ladder type delay line
  • FIGURE 6 is a graphic representation of the dispersion curves of the lines illustrated in FIGURES 3 to 5;
  • FIGURES 7 to 9 and 11 illustrate four embodiments of the invention comprising means for decreasing the magnetic coupling
  • FIGURE 10 is a graphic representation of the dispersion curves of lines in accordance with FIGURES 7 to 9,
  • FIGURE 12 is a cross section through a crossed field traveling wave tube comprising a delay line in accordance with FIGURE 9;
  • FIGURES 13 and 14 are respectively an axial section and a transverse cross section through a magnetron comprising a delay line in accordance with FIGURE 8 curved to circular shape.
  • the ladder type delay line of known construction comprises two longitudinal lateral members 1 and a series of rungs 2 spanning the space between the lateral members.
  • the two lateral members are mounted on a metal base plate 3 and the length of the rungs 2 is approximately M2, A being the operating wave length of the line.
  • FIGURE 2 illustrates how the delay line of FIGURE 1 may be assimilated to a chain of filter-type circuits having lumped constants.
  • the dotted line 14 in FIGURE I comprising a rung 2 and the closed path along the walls of the lateral members 1 and across the base plate 3 may be considered the equivalent of an anti-resonant circuit comprising a coil L and a capacitor C tuned to M 2.
  • the distribution of potentials on each rung, as also in each half wave circuit, is such that the potential is zero at the extremities and maximum at the center. Consequently, in the central zone of the rung an electrical field of maximum value is coupled with the electrical fields of the neighboring rungs. This coupling between the electrical fields is the equivalent of' the capacitor C of FIGURE 2.
  • FIGURE 2 discloses a chain of anti-resonant circuits coupled electrically by the capacitors C and magnetically by the induction circuits L L It is known that in this type of chain the electrical and magnetic couplings are mutually opposed so that the resonant coupling is very weak.
  • FIGURE 3 where the same reference numerals designate the same elements as in FIGURE 1, the electrical coupling between the successive rungs is decreased by in serting a filler member 4 between the base plate 3 and the rungs 2.
  • the filler member 4 extends longitudinally of the delay line or parallel to the locus of the rungs 2, the length of the member 4 being greater than either the space between adjacent rungs or the width of each rung has the effect of deforming the electrical field in the vicinity of the central zones of the rungs whereby a portion of the lines of force is deflected and redirected from each rung toward the filler member instead of toward the neighboring rung.
  • baffles are positioned in the spaces between the rungs 2, the width of the baflles being such as to extend over the central zones of the rungs.
  • the capacitor C of FIGURE 2 is replaced by two capacitors connected in series, the result being well known in that it provides a reduced resultant capacity.
  • FIGURE 5 discloses a combination of the filler member 4 of FIGURE 3 and of the baffies 5 of FIGURE 4.
  • Decoupling by means of bafiles in accordance with FIGURES 4 and 5 has the added advantage, in traveling wave tubes wherein it is well known that the beam gradually bends toward the anode as it progresses along the interaction space, that the baffles rather than the rungs are exposed to the stream of electrons.
  • the electrons are absorbed by massive elements which have a good heat dissipation.
  • the upper surfaces of the bafiies 5 which are exposed to the stream of electrons propagated in the interaction space along the delay line are parallel to the locus of the rungs longitudinally of the line as well asv paralleling the rungs transversely of the line.
  • the disposition of the flat electron beam along the delay line may be generally the same as that illustrated in FIGURE 12 With regard to the base plate 3" and the transversely extending rungs thereon which are described hereinafter.
  • the electron beam thus passes in interacting relationship with the rungs on the side thereof opposite the base plate 3.
  • FIGURE 6 is a graphic representation of the ratio between the speed of light c and the phase propagation velocity v as a function of the wave length A, from which it is possible to evaluate the dispersion.
  • the curve 1 corresponds to the delay line of FIGURE 3 and the curves 2 and 3 to the delay line of FIGURE 5 wherein the bat-Hes 5 are of diflferent heights.
  • the straight line 4 indicates the locus of the cut-off frequencies.
  • FIGURES 7 to 9 illustrate the three embodiments of the invention wherein means are incorporated for decreasing the magnetic coupling, the characteristic feature common to these three embodiments being that the rungs are divided into two groups occupying alternate odd and even positions, the rungs of at least one group being bent at right angles and the extremities thereof being implanted in the surface of a member separate from that in which the ends of the other group are implanted.
  • the odd rungs 2 are conventional, whereas the even rungs 2" are bent downwardly and their ends are implanted into the surface of elements 13 dis- 4 tinct from the surface of the lateral members 1 in which the ends of the rungs 2 are implanted.
  • both groups of rungs are bent at right angles, one group having their ends implanted in the upper level of a stepped lateral member 1 and the other group in the lower level thereof, whereby the end of the respective groups are implanted in two distinct surfaces.
  • the width of one group between the bent portions thereof is difierent from the width of the rungs of the other group, but the overall length of each rung is equal to approximately M2.
  • FIGURE 10 is a graphic representation similar to that of FIGURE 6 showing the dispersion curves 1, 2 and 3 corresponding respectively to the delay lines of FIGURES 7, 8 and 9.
  • the straight line 4 indicates the locus of the cut-off frequencies, and the portions shown respectively in full, and in broken lines having the same significance as in FIGURE 6. It will be seen that the more effective the magnetic decoupling the weaker the dispersion, the slope of the curves being gradually reduced and be coming more regular.
  • FIGURE 11 There are, of course, many other possibilities of magnetic decoupling, for example as shown in FIGURE 11 where baffies 5' are inserted between the end portions of the rungs, this arrangement being similar with respect to magnetic coupling to what is shown for electrical coupling in FIGURE 4.
  • decoupling is obtained by lengthening or complicating the path through which the current circulating on the surface of the metal mass shortcircuiting the rungs would have to pass between the adjacent ends of two consecutive rungs.
  • the invention may be applied in practice to many types of electron discharge tubes operating on the principle of interaction between a beam and a wave.
  • Delay lines according to the invention are more particularly intended, however, for use in traveling wave tubes wherein the interaction between the beam and the wave takes place within the range of crossed electrical and magnetic fields, these tubes operating as amplifiers in accordance with one mode of propagation wherein the phase velocity is of the same sign as the group velocity, or as oscillators in accordance with a mode of propagation wherein the two velocities have opposite signs.
  • the full line portions of the curves decrease when the wave length increases which indicates that the phase velocity has the same sign as the group velocity for the mode of propagation corresponding to those portions of the curves.
  • the broken line portions increase on the contrary which corresponds to a phase velocity opposed to the group velocity.
  • the full line portions increase and the broken line portions decrease or are substantially horizontal. Consequently the delay lines of which the dispersion is indicated by the curves of FIGURES 6, i.e. electrically uncoupled delay lines, may be used in crossed field tubes operating as amplifiers in accordance with a mode of propagation the phase velocity of which is as high as possible, or as oscillators in accordance with a mode the phase velocity of which is lower than the smallest possible velocity.
  • the delay lines of which the dispersion is given by FIGURE 10, i.e. magnetically uncoupled delay lines may be used in crossed field tubes operating as oscillators in accordance with a mode of propagation at maximum phase velocity, or as amplifiers in accordance with a mode of lower phase velocity.
  • FIGURE 12 illustrates by way of example a transverse section through a tube including a delay line in accordance with the present invention.
  • the delay line is illustrated by way of example a transverse section through a tube including a delay line in accordance with the present invention. The delay line.
  • FIGURE 12 In addition to the rungs 2' and 2" and the plates 3 and 3" there are shown in FIGURE 12 the usual negative electrode 6, the electron beam 7 passing between the electrode 6 and the delay line, side walls 8 closing the tube, and magnetic poles 9.
  • the rectilinear shape of the tube shown in FIGURE 12 is in no way intended to limit the invention.
  • the delay line may be bent to cylindrical shape for use in circular traveling wave tubes.
  • the property of low dispersion obtained with the delay lines according to the present invention renders them particularly suitable for use in magnetrons without the necessity for using the connections known as straps which are inserted for artificially reducing the high dispersion of known anodes and for preventing the magnetron from jumping too easily from one frequency of oscillation to another.
  • the delay lines according to the present invention having a low dispersion and being comparable to a wide band circuit, already prevent these frequency jumps without the use of straps.
  • FIGURES l3 and 14 are respectively an axial section and a cross section through a magnetron using a delay line for example as in FIGURE 8 curved to circular shape, but it must be understood that any other line in accordance with the invention could be substituted.
  • the rungs 2' and 2 there are shown the rungs 2' and 2", the lateral members 1 and base plate 3 being rolled to cylindrical shape.
  • a cathode 11 In the axis of the magnetron is positioned a cathode 11 and the magnetic field is produced by a coil 12.
  • a micro-wave delay line comprising at least one metal base plate, a pair of lateral members fixed to the base plate and extending along the side edges thereof and a series of parallel rungs extending between the two lateral members and fixed thereto on both extremities, said rungs being of a length approximating one-half the length of the wave to be delayed by the line, means being provided for reducing magnetic coupling between adjacent extremities of successive rungs on each side of said series.
  • a delay line as claimed in claim comprising two base plates and a pair of lateral members mounted on each base plate, one group of rungs being connected to each pair of lateral members.
  • a delay line as claimed in claim 1 comprising bafiles positioned between end portions of consecutive rungs and mounted on said base plate adjacent to said lateral members.
  • each lateral member is curved to circular shape in a plane perpendicular to the longitudinal direction of said rungs.
  • a microwave delay line comprising at least one metal base plate, a pair of lateral members essentially parallel to said base plate and extending along the side edges thereof and a series of essentially parallel rungs extending between the two lateral members and fixed thereto on both extremities, said rungs being of a length approximating one-half the length of the wave to be delayed by the line, said rungs comprising a rectilinear portion extending at least over a part thereof, said line being electrically equivalent to a chain of coupled circuits including both electrical coupling and magnetic coupling, and lengthening means for the path followed by microwave current between extremities of said rectilinear portions of adjacent rungs on each side of said series with respect to the direct rectilinear path between said extremities, whereby said magnetic coupling is reduced to a small value with respect to said electrical coupling.
  • each lateral member is curved to circular shape in a plane perpendicular to the longitudinal direction of said rungs.
  • a traveling wave tube comprising an envelope, a delay line for microwave inside said envelope comprising a metal base plate, at least one pair of lateral members extending longitudinally along the edges of said base plate, and a series of parallel rungs extending between said lateral members and connected thereto on both extremities, the length of said rungs being substantially equal to one half the length of the wave to be delayed by the line, said rungs comprising a rectilinear portion extending at least over a portion thereof, said line being electrically equivalent to a chain of coupled circuits including both electrical coupling and magnetic coupling, and lengthening means for the path followed by microwave current between extremities of said rectilinear portions of adjacent rungs on each side of said series with respect to the direct rectilinear path between said extremities, whereby said magnetic coupling is reduced to a small value with respect to said electrical coupling.
  • a delay line for microwave inside said envelope comprising a metal base plate, at least one pair of lateral members extending longitudinally along the edges of said base plate, and a series of parallel rungs extending between said lateral members and connected thereto on both extremities, the length of said rungs being substantially equal to one-half the length of the wave to be delayed by the line, said rungs comprising a rectilinear portion extending at least in a part thereof, said line being electrically equivalent to a chain of coupled circuits including both electrical coupling and magnetic coupling, and lengthening means for the path followed by microwave current between extremities of said rectilinear portions of adjacent rungs on each side of said series, with respect to the direct rectilinear path between said extremities, whereby said magnetic coupling is reduced to a small value with respect to said electrical coupling.
  • a ladder-type delay line for use in microwave tubes operating by interaction between the beam of electrons and an ultra-high frequency wave traveling through the delay line comprising support means and a chain of successively coupled circuits each formed by a pair of successive rungs of the delay line ladder, said rungs having both their ends secured to supporting surfaces of said support means, wherein means are provided for tightening the coupling between the successive circuits of the line, by reducing the magnetic coupling between said circuits, characterised in that the rungs are divided into two sets, even and odd, the rungs of at least one set having both their ends bent at angles to the central portions of these rungs, said ends being secured to a surface diiferent from the surface to which are secured the ends of the rungs of the other set.

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  • Microwave Tubes (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
  • Microwave Amplifiers (AREA)
  • Particle Accelerators (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
US838813A 1952-06-28 1959-07-31 Ladder type delay line Expired - Lifetime US3068432A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
FR1068673D FR1068673A (fr) 1952-06-28 1952-06-28 Perfectionnements aux lignes à retard du type en echelle pour tubes à ondes progressives ou magnétrons
US356050A US2920227A (en) 1952-06-28 1953-05-19 Ladder type delay line
DEC7802A DE953269C (de) 1952-06-28 1953-06-26 Verzoegerungsleitung der Sprossenbauart fuer Wanderfeldroehren oder Magnetronroehren
DEC11647A DE963896C (de) 1952-06-28 1953-06-26 Verzoegerungsleitung der Sprossenbauart fuer Elektronenroehren
GB17972/53A GB761768A (en) 1952-06-28 1953-06-29 Improvements in or relating to delay lines for microwave tubes
GB33619/55A GB761850A (en) 1952-06-28 1953-06-29 Improvements in or relating to delay lines for microwave tubes
FR64659D FR64659E (fr) 1952-06-28 1953-07-11 Perfectionnements aux lignes à retard du type en échelle pour tubes à ondes progressives ou magnétrons
DEC9754A DE961551C (de) 1952-06-28 1954-08-06 Verzoegerungsleitung der Sprossenbauart fuer Wanderfeldroehren oder Magnetronroehren
US838813A US3068432A (en) 1952-06-28 1959-07-31 Ladder type delay line

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR953269X 1952-06-28
US356050A US2920227A (en) 1952-06-28 1953-05-19 Ladder type delay line
US838813A US3068432A (en) 1952-06-28 1959-07-31 Ladder type delay line

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US3068432A true US3068432A (en) 1962-12-11

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US838813A Expired - Lifetime US3068432A (en) 1952-06-28 1959-07-31 Ladder type delay line

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DE (2) DE963896C (fr)
FR (1) FR64659E (fr)
GB (2) GB761768A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3322996A (en) * 1962-12-17 1967-05-30 Varian Associates Electron discharge devices and molybdenum slow wave structures, the molybdenum slow wave structures having grain alignment transverse to the electron path
US3699379A (en) * 1970-01-26 1972-10-17 Thomson Csf Delay lines

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2890384A (en) * 1953-09-24 1959-06-09 Raytheon Mfg Co Traveling wave electronic devices
GB809951A (en) * 1957-03-20 1959-03-04 Standard Telephones Cables Ltd Improvements in or relating to travelling wave tubes
DE1260638B (de) * 1957-05-22 1968-02-08 Siemens Ag Verzoegerungsleitung mit Bandpasscharakter, insbesondere fuer Lauffeldroehren, und Verfahren zu ihrer Herstellung sowie Lauffeldroehren mit solchen Verzoegerungsleitungen
FR1284006A (fr) * 1960-12-30 1962-02-09 Csf Perfectionnements aux lignes à retard en échelle
US4409518A (en) * 1981-07-29 1983-10-11 Varian Associates, Inc. TWT Interaction circuit with broad ladder rungs

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2511407A (en) * 1947-01-09 1950-06-13 Csf Amplifying valve of the progressive wave type
US2745984A (en) * 1952-03-25 1956-05-15 Bell Telephone Labor Inc Microwave oscillator
US2768322A (en) * 1951-06-08 1956-10-23 Bell Telephone Labor Inc Interdigital filter circuit
US2827589A (en) * 1952-05-17 1958-03-18 Bell Telephone Labor Inc Electron discharge device
US2827588A (en) * 1951-04-28 1958-03-18 Csf Travelling wave discharge tube arrangements utilizing delay lines

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2511407A (en) * 1947-01-09 1950-06-13 Csf Amplifying valve of the progressive wave type
US2827588A (en) * 1951-04-28 1958-03-18 Csf Travelling wave discharge tube arrangements utilizing delay lines
US2768322A (en) * 1951-06-08 1956-10-23 Bell Telephone Labor Inc Interdigital filter circuit
US2745984A (en) * 1952-03-25 1956-05-15 Bell Telephone Labor Inc Microwave oscillator
US2827589A (en) * 1952-05-17 1958-03-18 Bell Telephone Labor Inc Electron discharge device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3322996A (en) * 1962-12-17 1967-05-30 Varian Associates Electron discharge devices and molybdenum slow wave structures, the molybdenum slow wave structures having grain alignment transverse to the electron path
US3699379A (en) * 1970-01-26 1972-10-17 Thomson Csf Delay lines

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Publication number Publication date
DE963896C (de) 1957-05-16
DE953269C (de) 1956-11-29
GB761850A (en) 1956-11-21
FR64659E (fr) 1955-12-01
GB761768A (en) 1956-11-21

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