US3218582A - Delay line structure - Google Patents

Delay line structure Download PDF

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Publication number
US3218582A
US3218582A US105049A US10504961A US3218582A US 3218582 A US3218582 A US 3218582A US 105049 A US105049 A US 105049A US 10504961 A US10504961 A US 10504961A US 3218582 A US3218582 A US 3218582A
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Prior art keywords
delay
members
slot
portions
rung
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Expired - Lifetime
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US105049A
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English (en)
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Arnaud Jacques
Renaud Claude
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Thales SA
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CSF Compagnie Generale de Telegraphie sans Fil SA
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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 for travelling wave tubes, especially to delay lines constituted by at least one series of parallel bars, disposed parallelly to at least two surfaces usually called back-plates, located in a common plane and effectively separated between themselves by a slot perpendicular to the bars.
  • the wave which propagates along the delay line according to the symmetric mode is utilized for the interaction with the electron beam, whereby the symmetric mode refers to a symmetric distribution of the high frequency potential with respect to the median plane of the bar.
  • the delay lines of the type in question are also the seat of propagation of at least one parasitic anti-symmetric mode which propagates on the wave lengths of the useful band corresponding to the utilization of the symmetric mode, and which impairs in an undesirable manner the proper functioning of the tube.
  • Another object of the present invention resides in the provision of a delay line structure for high power travelling wave tubes which is mechanically sturdy and robust and which lends itself readily to the dissipation of large quantities of heat normally generated in high power tubes.
  • a further object of the present invention resides in the provision of a wave retardation structure which effectively displaces the anti-symmetric modes outside the band of wave lengths in which functions the symmetric desired mode.
  • FIGURE 1 is a perspective view of a delay line in accordance with the present invention utilizing T-shaped delay elements
  • FIGURE 2 is a plan View with the cross section taken along line 2-2 of FIGURE 1,
  • FIGURE 3 is a perspective view, similar to FIGURE 1, of a modified embodiment of a delay line structure in accordance with the present invention utilizing a double-T arrangement,
  • FIGURE 4 is a perspective view, similar to FIGURE 1, of still a further modified embodiment of a delay line structure in accordance with the present invention utilizing a double 1r arrangement, and
  • FIGURE 5 is a diagram illustrating the dispersion curves for a delay line structure in accordance with the present invention, given herein only to explain the advantages of the present invention.
  • a line constituted by at least a series of parallel bars, disposed parallelly to at least two walls or back-plates located in a common plane and effectively separated between themselves by a slot perpendicular to the bars, is characterized by at least one 'short-circuiting bridge connecting the edges of the slot and disposed in one of the spaces between consecutive bars of the series of the line.
  • the same may form between themselves a periodic sequence, and in one particular case of the present invention, the periodicity thereof may be equal to that of the bars.
  • the bridge portions may be made either of good conductive metal or resistant material, or may also be covered by an attenuation. This resistance or attenuation provides a supplementary contribution to the elimination of the anti-symmetric mode owing to the absorption exercised thereby.
  • FIG- URES 1 and 2 represent, respectively, a perspective view and a plan view taken along the plane of line 22 of FIGURE 1
  • the delay line illustrated in these figures represents, in its entirety, a T-shaped structure essentially similar to FIGURE 4 of the aforementioned copending application Serial No. 793,835.
  • This delay line includes a rectangular wave guide 8 of which the upper wall 10 is effectively slotted at 9, and forms also two back-plates 10 and 10' located in a common plane and effectively separated by the slot 9.
  • the bars such as 11 Parallelly to these back-plates 10 and 10 and perpendicular to the slot 9 extend the bars such as 11, each forming part of an element in the shape of a T, of which the leg portion 12 extends through the slot 9 and is secured along the bottom of the guide 8 in any suitable manner.
  • the T-shaped elements 11 form a regular sequence or series which imparts the characteristic of geometric periodicity to the delay structure.
  • At least one metallic short-circuiting bridge 13 connects the edges of the slot 9.
  • each bridge is disposed within the interval between two consecutive leg portions 12.
  • FIGURE 3 which illustrates a modified embodiment of the present invention essentially analogous to the structure of FIGURE 8 of the aforementioned copending application Serial No. 793,835, and which, in elfect, represents, next to one another, two delay line systems of FIGURE 1 of the instant application forming an assembly with elements of double-T shape having bars 11 and 11' and the leg portions 12 and 12', also shows the short circuiting bridges 13 and 13' which connect the edges of each of the slots 9 and 9.
  • FIGURE 4 shows, in perspective view, a delay line resulting from the juxtaposition, alongside one another,
  • the delay line of FIGURE 4 of the present application also includes bars designated in this figure by reference numeral 11 by analogy with the preceding figures which bars extend parallelly to the back plates 19 and and are supported again in the center thereof by the leg portions such as leg portions 12.
  • the extremities of the bars 11 are no longer free but are embedded within the lateral wall portions 14 and 14 which themselves are connected to the back plates 10 and 10' in any suitable manner. Consequently, the elements of this delay line structure are in the shape of a double 1r.
  • the short-circuiting bridges 13 of the embodiment of FIGURE 4 are disposed, in accordance with the present invention, across the slot 9 between the back-plates or wall portions 10 and 10'.
  • FIGURE 5 represents a dispersion diagram generally valid for the different embodiments of delay lines described hereinabove and intended to explain the effect of the bridge portions 13.
  • this diagram which indicates the delay ratio c/ v (0 being equal to the speed of light and v being equal to the phase velocity of the wave) as a function of the wave length A
  • curve 16 the same curve for one of the anti-symmetric undesirable modes, whereby it is noted that a single anti-symmetric mode exists in the case of a cell in the shape of a simple T as shown in FIGURES 1 and 2 of the present application but three anti-symmetric modes exist in the cases of cells of double T or 11' shape as shown in FIGURES 3 and 4, and more than that in those cases of possibly multiple cells.
  • the single curve 16 is utilized herein to simplify the explanation and is to be considered typical for each of these undesirable anti-symmetric modes. Without the bridge portions 13, that is with known delay lines according to the aforementioned patent or patent application, it is noted that the curve 16 falls within the useful band of the curve 15, defined, for example, between the wave lengths A and x Consequently, the anti-symmetric mode or modes impair the proper operation of the tube.
  • bridge portions 13 While the present specification refers to slots 9 and bridge portions 13, it is understood that such terminology is used only for purposes of convenience. In practice, the bridge portions may be added after machining slots into the conductive back plates or may also be effectively formed by merely producing the apertures into which extend the leg portions 12 of the delay elements thereby providing the same effect.
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode, comprising at least one series of substantially identical conductive delay members each including at least a rung portion, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to the rung portions of said members and provided with at least one slot perpendicular to said rung portions, each delay member including a further portion extending into said slot, and bridging means across said slot for preventing the propagation in said line of an anti'symmetric mode near the operating frequencies of the desired symmetric mode, said bridging means being located between successive delay members in said alignment.
  • a delay circuit adapted to propagate therealong waves of a predetermined desired mode, comprising at least one series of essentially similar conductive delay elements providing a periodic structure and each including at least a rung portion and a leg portion, said two portions being disposed at an angle to each other in mutually different directions, plate means extending essentially parallelly to the said rung portions and effectively provided with at least one slot perpendicular to said rung portions and receiving therein the leg portions, and means in said delay structure for effectively preventing the propagation therein of an anti-symmetric mode near the operating frequencies of the desired symmetric mode includingbridging means extending across said slot and located between successive delay members in said circuit.
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising at least one series of substantially identical conductive delay members each including at least one rungportion and a leg portion disposed at an angle to said rungportion, the two portions of each delay member being rigidly connected with each other, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to said rung portions of said members and effectively provided with at least one slot essentially perpendicular to said rung portions, bridging means across said slot for preventing the propagation in said lines of an anti-symmetric mode near the operating frequencies of the desired mode, said bridging means being located between successive delay members in said alignment, at least one series of said leg portions being arranged to pass through said slot intermediate two bridging means, and means for effectively interconnecting electrically the free extremities of said leg portions.
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising at least one series of substantially identical conductive delay members each including at least a rung portion, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to the rung portions of said members and effectively provided with a least one slot perpendicular to said rung portions, each delay member including a further portion extending into said slot, and bridging means across said slot for preventing propagation in said line of an antisymmetric mode near the operating frequencies of the desired mode, said bridging means being located between successive delay members in said alignment, and said delay members and said conductive plate being of highly conductive metal while said bridge means is of relatively resistant metal.
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising at least one series of substantially identical conductive delay members each including at least a rung por tion, said members being respectively located in essential- 1y parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to the rung portions of said members and effectively provided with a least one slot perpendicular to said rung portions, each delay member includuing a further portion extending into said slot, and bridging means across said slot for preventing propagation in said line of an anti-symmetric mode near the operating frequencies of the desired mode, said bridging means being located between successive delay members in said alignment, and being coated with an attenuating substance.
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising at least one series of substantially identical conductive delay members each including at least a rung portion having two free extremities and a leg portion disposed at an angle to said rung portion whereby said delay members are of approximately T-shape, the two portions of each delay member being rigidly connected with each other, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate etxending parallel to said rung portions of said members and eifectively provided with at least one slot essentially perpendicular to said rung portions, bridging means across said slot for preventing the propagation in said line of an anti-symmetric mode near the operating frequencies of the desired symmetric mode, said bridging means being located between successive delay members in said alignment, at least one series of said leg portions being arranged to pass through said slot intermediate two bridging means, and means for effectively interconnecting electrically the free extremities of said leg
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising at least one series of substantially identical conductive delay members each including at least one rung portion, conductive members connected to the extremities of said rung portion and a leg portion disposed at an angle to said rung portion so as to provide delay members of approximately multiple 7: shape, the two portions of each delay member being rigidly connected with each other, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to said rung portions of said members and provided with at least one slot essentially perpendicular to said rung portions, and bridging means across said slot for preventing the propagation in said line of an anti-symmetric mode near the operating frequencies of the desired symmetric mode, said bridging means being located between successive delay members in said alignment, at least one series of said leg portions being arranged to pass through said slot intermediate two bridging means, and means for effectively interconnecting electrically the free extremities of said leg
  • a delay circuit for microwaves adapted to propagate therealong waves of a predetermined desired mode comprising a plurality of series of substantially identical conductive delay members each including at least one rung portion having two free extremities and a leg portion disposed at an angle to said rung portion whereby the delay members of each series are of approximately T shape, the two portions of each delay member being rigidly connected with each other, said members being respectively located in essentially parallel periodically spaced planes and aligned in a direction at an angle to said planes, a conductive plate extending parallel to said rung portions of said members and effectively provided with a plurality of slots essentially perpendicular to said rung portions, and bridging means across said slot for preventing the propagation in said line of an anti-symmetric mode near the operating frequencies of the desired symmetric mode, said bridging means being located between successive delay members in said alignment, each respective series of said members being arranged to have its leg portions pass through one of said slots, respectively, intermediate two bridging means, and means for effectively interconnecting electrically the free extrem
  • a delay line structure adapted to propagate therealong waves of a predetermined desired mode comprising a rectangular metallic wave guide having two broad and two narrow walls, one of the broad walls being provided with a longitudinal slot in the middle thereof, a number of identical equidistant metallic bars disposed outside said wave guide in close, parallel and transverse relationship to said slotted Wall, each of said bars being supported in the middle thereof by a metallic support traversing said slot and fixed inside the wave guide to the other broad wall thereof, and electrical bridging means interconnecting the two halves of the slotted wall and disposed between successive bars to prevent the propagation in said lines of an anti-symmetric mode near the operating frequencies of the desired symmetric mode.
  • a delay line structure adapted to propagate therealong waves of a predetermined desired mode comprising a rectangular metallic wave guide having two broad and two narrow walls, one of the broad walls being provided with a longitudinal slot in the middle thereof, a number of identical equidistant metallic bars disposed outside said wave guide in close, parallel and transverse relationship to said slotted wall, each of said bars being supported in the middle thereof by a metallic support traversing said slot and fixed inside the wave guide to the other broad wall thereof, the length of said bars being substantially equal to the width of said broad walls, while the length of said supports is somewhat more than the width of said narrow walls, and electrical bridging means interconnecting the two halves of the slotted wall and disposed between successive bars to prevent the propagation in said lines of an anti-symmetric mode near the operating frequencies of the desired symmetric mode.
  • a delay circuit composed of two juxtaposed delay lines, each delay line being as claimed in claim 11.
  • a delay circuit composed of two juxtaposed delay lines, each of said delay lines being as claimed in claim 12.
  • a delay circuit adapted to propagate therethrough a predetermined desired mode for use in travelling wave tubes or the like comprising a plurality of substantially similar delay elements arranged to provide a periodic structure, each delay element comprising at least two connected portions disposed at an angle to each other and extending in mutually diiferent directions, and means operatively connected with said delay circuit for prevent- 7 ing the propagation in said delay circuit of an anti-symmetric mode near the operating frequencies of said desired symmetric mode including first conductive means electrically interconnecting a first portion of each delay element and second conductive means electrically connected to said first conductive means and extending at a relatively small distance from and at least over a major area of the second portion of each delay element to thereby provide a predetermined electric field distribution along both portions of each delay element, and bridging means disposed between successive first portions of said delay elements and operatively connecting said second conductive means within the area located between successive first portions of said delay elements.

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US105049A 1960-06-03 1961-04-24 Delay line structure Expired - Lifetime US3218582A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR829028A FR1266633A (fr) 1960-06-03 1960-06-03 Perfectionnements aux lignes à retard à barreaux et plafonds multiples pour tubes à ondes progressives

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US3218582A true US3218582A (en) 1965-11-16

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US (1) US3218582A (enrdf_load_stackoverflow)
DE (1) DE1240591B (enrdf_load_stackoverflow)
FR (1) FR1266633A (enrdf_load_stackoverflow)
GB (1) GB936094A (enrdf_load_stackoverflow)
NL (2) NL123018C (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3345586A (en) * 1962-09-10 1967-10-03 Sylvania Electric Prod Delay structure for traveling wave device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2827588A (en) * 1951-04-28 1958-03-18 Csf Travelling wave discharge tube arrangements utilizing delay lines
US2879437A (en) * 1954-05-29 1959-03-24 Csf Delay lines for high power discharge tubes
US2888595A (en) * 1951-03-15 1959-05-26 Csf Travelling wave delay tubes of the magnetron type
US2920227A (en) * 1952-06-28 1960-01-05 Csf Ladder type delay line
US2922918A (en) * 1955-01-17 1960-01-26 Csf Traveling wave oscillators
US2945981A (en) * 1955-06-13 1960-07-19 Bell Telephone Labor Inc Magnetron-type traveling wave tube
US3086180A (en) * 1958-02-27 1963-04-16 Csf Delay line for travelling wave tubes

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2888595A (en) * 1951-03-15 1959-05-26 Csf Travelling wave delay tubes of the magnetron type
US2827588A (en) * 1951-04-28 1958-03-18 Csf Travelling wave discharge tube arrangements utilizing delay lines
US2920227A (en) * 1952-06-28 1960-01-05 Csf Ladder type delay line
US2879437A (en) * 1954-05-29 1959-03-24 Csf Delay lines for high power discharge tubes
US2922918A (en) * 1955-01-17 1960-01-26 Csf Traveling wave oscillators
US2945981A (en) * 1955-06-13 1960-07-19 Bell Telephone Labor Inc Magnetron-type traveling wave tube
US3086180A (en) * 1958-02-27 1963-04-16 Csf Delay line for travelling wave tubes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3345586A (en) * 1962-09-10 1967-10-03 Sylvania Electric Prod Delay structure for traveling wave device

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FR1266633A (fr) 1961-07-17
DE1240591B (de) 1967-05-18
GB936094A (en) 1963-09-04
NL265454A (enrdf_load_stackoverflow)
NL123018C (enrdf_load_stackoverflow)

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