US3924151A - Delay line with low reflection attenuation for transit-time tubes - Google Patents

Delay line with low reflection attenuation for transit-time tubes Download PDF

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Publication number
US3924151A
US3924151A US503664A US50366474A US3924151A US 3924151 A US3924151 A US 3924151A US 503664 A US503664 A US 503664A US 50366474 A US50366474 A US 50366474A US 3924151 A US3924151 A US 3924151A
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delay line
line
bodies
attenuating
attenuating bodies
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US503664A
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English (en)
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Franz Gross
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Siemens AG
Siemens Corp
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Siemens Corp
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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
    • H01J23/30—Damping arrangements associated with slow-wave structures, e.g. for suppression of unwanted oscillations

Definitions

  • ABSTRACT A delay line with low reflection attenuation for transittime tubes, particularly for amplification of millimeter waves, employing a waveguide having a plurality of successive transverse walls which form line cells, each of which hasin addition to a central opening for passage of the electron beam, a coupling slot arranged alternately on opposite sides of the delay line, and provided with a plurality of a cylindrical attenuating bodies which project into the line cells with a penetration depth which varies uniformly along the course of the delay line for providing a reflection-free attenuation, in which such transverse wall are provided with recesses therein in which said attenuating bodies are respectively disposed and mechanically stably retained in operative position therein, such attenuating bodies being disposed diametrically opposite to the corresponding coupling slots and with the longitudinal axis of the cylindrical attenuating
  • the invention is directed to a delay line with low re flection attenuation, for transit-time tubes, in particular for the amplification of millimeter waves and utilizing a wave-guide with successive transverse walls which form line cells and, in addition to a central opening for the electron beam, are each provided with a'coupling slot, which slots are arranged alternately on opposite sides of the delay line, and provided with cylindrically shaped attenuating bodies which extend into the respective line cells with a depth of penetration which changes uniformly for providing a reflection-free attenuation in the course of the 'delay line.
  • Delay lines of this type have become known from German AS 2,134,966 in which the delay line attenuating bodies are disposed in cavity resonators which are specially tuned to frequencies in the region of the cuttoff frequency and which, considered in radial direction, are arranged in a series of interaction cells of the delay line (line cells) on a line parallel to the beam direction.
  • the attenuating bodies may project into the line cells by equal distances, whereas in the case of a delay line employing a plurality of amplifier sections which are merely electronically coupled to one another, the depth of penetration preferably decreases with an increasing distance from the adjacent section end (attenuation tapering).
  • attenuating bodies of cylindrical shape are inset into the spacers, in a plane which is at right angles to the plane of symmetry of the delay line.
  • the cylindrical attenuating bodies are provided with different penetration depths by division into various sized portions along their surface line.
  • the attenuation arrangement of the described delay line has, in accordance with the tuning of the cavity resonators, a frequency-selective effect and also is favorably direction-dependent with low reflection, but involves a considerable production outlay, the difficulties of which are particularly evident when considering the small dimensions involved in millimeter wave technique.
  • the cavity resonators which are to be provided with a side opening must always be produced with particular care, must accurately close off the two ends of the attenuating bodies which project into the line cells with the sides of the spacers which are adjacent to the transverse walls, for reasons of heat dissapation, and finally very great, time-consuming precision is required to remove from the attenuating bodies, which for example are only fractions of a millimeter thick, portions of which furthermore are to possess specific size relationships to one another along the surface line of said bodies.
  • cylindrical attenuating bodies are capable of being simply produced, it merely being necessary to cut them off a suitable rod in the particular length desired.
  • the attenuating bodies likewise are mechanically stable and can be readily held in operative position in a recess, or extending completely through openings in the transverse walls. If they are soldered in place, the heat losses which arise in the attenuating bodies are conducted from the reaction chamber by shortheat conducting paths which are not obstructed by a heat barrier.
  • the shortest heat conducting paths are produced in the particularly critical tapering area as here the attenuating bodies which, in the arrangement proposed by the invention, have a relatively short depth of penetration, act mainly in a current-attenuating fashion (they attenuate the wall currents, tie, the magnetic fields) and thus heat can form practically only in surface areas of the attenuating bodies surrounded by the transverse wall.
  • the attenuating bodies projecting more deeply into the wave-guide cells also act in field attenuating fashion.
  • the longer heat paths which thus occur do not, however, entail any danger of destruction since the high frequency energy which is to be attenuated has already, in a large part, been consumed in the preceding relatively short attenuating bodies.
  • Attenuating bodies in a delay line along the axis through openings in the transverse walls, for example see German AS 1,298,202. Such attenuating bodies, however, are elongated and penetrate several transverse Walls. Attenuation tapering is provided by employing a wedge-shaped tapering of the two ends of the bodies.
  • the portion of the delay line illustrated in FIG. 1 is adapted for use in a travelling wave tube for the amplification of millimeter waves, in which the delay line itself comprises a plurality of line discs 1, 2 which are arranged in a series in the direction of the electron beam and are disposed in a stacked arrangement to form a solid block structure.
  • Each line disc is recessed or indented with such recess in each case other than for the end member 3 forming with the adjacent member a line cell 4 defined by cell-dividing transverse walls 5.
  • Each of the latter is provided with a central electron beam opening 6 and a coupling opening 7, with successive line discs being rotatively displaced with respect to each other by 180, and one pair, in each case, forming one period of the delay line.
  • the stacked line has a backwards running fundamental wave in the longest wave transmission whereby it is operated in the first forward running space harmonic i.e. between the 1r and the Zn point.
  • each line disc other than the end disc 3 is provided at the side thereof opposite the coupling opening 7 with a recess 8, which in the embodiment illustrated comprises a bore extending through the transverse wall and which is adapted to receive a cylindrical attenuating body 9.
  • the attenuating body 9' may be soldered to the transverse wall 5 and projects into the respective adjacent line cells 4 at opposite sides of the particular transverse wall.
  • the attenuating bodies are graduated as to their length l and are disposed in staggered relation so that their penetration lengths s s initially uniformly increase along the course of the delay line and then uniformly decrease.
  • Attenuating bodies 9 which individually attenuate two adjacent line cells 4 provides not only a mechanically durable attachment of the attenuating bodies but also possesses the advantage that it is possible to achieve the desired results with a relatively low number of attenuating bodies, and to achieve in each case two different penetration depths merely by a simple staggering of one properly dimensioned attenuating body.
  • the delay line frequently is divided into different line portions or sections which are separated from one another by socalled severs (isolating section terminations) and which are merely electronically coupled to one another.
  • severs isolated section terminations
  • the amplification factors of the individual line portions are so designed that such portions do not start to oscillate.
  • the input coupled I-IF energy is to be absorbed at the section terminations as fully and in as reflection-free a manner as possible.
  • FIG. 2 illustrates a delay line in accordance with the invention incorporating such a design. It differs from the first embodiment described merely in that it possesses an isolating section termination 10 having an electron beam opening 11 and that the entry paths s s, of the attenuating bodies 9 merely increase but do not subsequently decrease along the course of the delay line.
  • the attenuation arrangement is so dimensioned that the main part of the HF energy which enters from the left side of the figure is in fact converted in the tapering region.
  • the uniform changes in the penetration paths can fulfill different functions which are favorable for a low-reflection attenuation. For example, such penetration can increase linearly with the distance from one end of the delay line. For as uniform as possible a heat loading of the delay line it is also possible to select a dependence in which the amount of heat converted in each individual attenuated line cell is approximately the same.
  • a multi-portion delay line constructed in accordance with the invention, with an internal line crosssection of 4.7 mm, only six attenuating bodies 9 having a thickness of 0.8 mm and a length of up to 3 mm (corresponding to a maximum penetration distance of 1.1 mm) were employed in one portion to achieve a practically reflection-free attenuation.
  • Wave guide cells 4 which were provided with attenuating bodies having the full attenuation length were attenuated by more than 4.5 db.
  • Possible materials'for the attenuating bodies are, for example, tungsten aluminum oxide for lossy beryllium oxide or boron nitride.
  • an attenuation arrangement constructed in accordance with the invention, is also dependent upon frequency and in fact in such manner that its attenuating force increases drastically towards the band edge in the region of the upper cut-off frequency of the operating band. This property ensures that, in particular, the undesired 2w oscillation is prevented, which otherwise can readily be excited when the line voltage increases.
  • a delay line with low reflection attenuation for transit time tubes, particularly for amplification of mi]- liineter waves comprising a wave-guide having a plurality of successive transverse walls which form line cells, each of which have, in addition to a central openingfor the passage of the electron beam, a coupling slot arranged alternately on opposite sides of the delay line, and a plurality of cylindrical attenuating bodies which project into the line cells with a penetration depth which varies uniformly along the course of the delay line for effecting a reflection-free attenuation, said transverse walls having recesses therein in which said attenutating bodies are respectively disposed in mechanically stable operative positions diametrically opposite to the cooperable coupling slots, the longitudinal axes of the cylindrical attenuating bodies and of the delay line being at least approximately parallel to one another.

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  • Microwave Tubes (AREA)
US503664A 1973-09-19 1974-09-06 Delay line with low reflection attenuation for transit-time tubes Expired - Lifetime US3924151A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2347209A DE2347209C2 (de) 1973-09-19 1973-09-19 Reflexionsarm bedampfte Verzögerungsleitung für Lauffeldröhren

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US3924151A true US3924151A (en) 1975-12-02

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US (1) US3924151A (enrdf_load_html_response)
JP (1) JPS5750334B2 (enrdf_load_html_response)
DE (1) DE2347209C2 (enrdf_load_html_response)
FR (1) FR2244255B1 (enrdf_load_html_response)
GB (1) GB1468257A (enrdf_load_html_response)
IT (1) IT1021437B (enrdf_load_html_response)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4013917A (en) * 1974-12-03 1977-03-22 Nippon Electric Company, Ltd. Coupled cavity type slow-wave structure for use in travelling-wave tube
US4088924A (en) * 1975-12-18 1978-05-09 Siemens Aktiengesellschaft Delay line for travelling-wave tubes

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2525845C3 (de) * 1975-06-10 1978-06-22 Siemens Ag, 1000 Berlin Und 8000 Muenchen Breitbandig reflexionsarm bedämpfte Verzögerungsleitung und Verfahren zu ihrer Herstellung
JPS5512682A (en) * 1978-07-14 1980-01-29 Nec Corp Coupled cavity wave travelling tube
DE2856778C3 (de) * 1978-12-29 1981-12-03 Siemens AG, 1000 Berlin und 8000 München Selektiv bedämpfte Wanderfeldröhre

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360679A (en) * 1964-02-21 1967-12-26 Varian Associates Electron discharge device having lossy resonant elements disposed within the electromagnetic field pattern of the slow-wave circuit
US3412279A (en) * 1965-09-13 1968-11-19 Varian Associates Electromagnetic wave energy absorbing elements for use in high frequency electron discharge devices having traveling wave tube sections
US3471738A (en) * 1966-01-26 1969-10-07 Thomson Varian Periodic slow wave structure
US3602766A (en) * 1969-02-12 1971-08-31 Hughes Aircraft Co Traveling-wave tube having auxiliary resonant cavities containing lossy bodies which protrude into the slow-wave structure interaction cells to provide combined frequency sensitive and directionally sensitive attenuation
US3832593A (en) * 1972-06-28 1974-08-27 Siemens Ag Selectively damped travelling wave tube

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3360679A (en) * 1964-02-21 1967-12-26 Varian Associates Electron discharge device having lossy resonant elements disposed within the electromagnetic field pattern of the slow-wave circuit
US3412279A (en) * 1965-09-13 1968-11-19 Varian Associates Electromagnetic wave energy absorbing elements for use in high frequency electron discharge devices having traveling wave tube sections
US3471738A (en) * 1966-01-26 1969-10-07 Thomson Varian Periodic slow wave structure
US3602766A (en) * 1969-02-12 1971-08-31 Hughes Aircraft Co Traveling-wave tube having auxiliary resonant cavities containing lossy bodies which protrude into the slow-wave structure interaction cells to provide combined frequency sensitive and directionally sensitive attenuation
US3832593A (en) * 1972-06-28 1974-08-27 Siemens Ag Selectively damped travelling wave tube

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4013917A (en) * 1974-12-03 1977-03-22 Nippon Electric Company, Ltd. Coupled cavity type slow-wave structure for use in travelling-wave tube
US4088924A (en) * 1975-12-18 1978-05-09 Siemens Aktiengesellschaft Delay line for travelling-wave tubes

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Publication number Publication date
FR2244255B1 (enrdf_load_html_response) 1979-08-03
IT1021437B (it) 1978-01-30
GB1468257A (en) 1977-03-23
JPS5060162A (enrdf_load_html_response) 1975-05-23
JPS5750334B2 (enrdf_load_html_response) 1982-10-27
DE2347209C2 (de) 1975-03-06
FR2244255A1 (enrdf_load_html_response) 1975-04-11
DE2347209B1 (de) 1974-07-11

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