EP0587481B1 - Radial electron tube - Google Patents

Radial electron tube Download PDF

Info

Publication number
EP0587481B1
EP0587481B1 EP19930402154 EP93402154A EP0587481B1 EP 0587481 B1 EP0587481 B1 EP 0587481B1 EP 19930402154 EP19930402154 EP 19930402154 EP 93402154 A EP93402154 A EP 93402154A EP 0587481 B1 EP0587481 B1 EP 0587481B1
Authority
EP
European Patent Office
Prior art keywords
electron tube
cathode
tube according
cavity
resonant cavity
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
EP19930402154
Other languages
German (de)
French (fr)
Other versions
EP0587481A1 (en
Inventor
Guy Clerc
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.)
Thales Electron Devices SA
Original Assignee
Thomson Tubes Electroniques
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
Application filed by Thomson Tubes Electroniques filed Critical Thomson Tubes Electroniques
Publication of EP0587481A1 publication Critical patent/EP0587481A1/en
Application granted granted Critical
Publication of EP0587481B1 publication Critical patent/EP0587481B1/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
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • H01J25/04—Tubes having one or more resonators, without reflection of the electron stream, and in which the modulation produced in the modulator zone is mainly density modulation, e.g. Heaff tube

Definitions

  • the present invention relates to electronic vacuum tubes used in particular as power amplifiers in the UHF band.
  • the first type includes electron beam amplitude modulation tubes and the second type includes electron beam speed modulation tubes electrons.
  • Amplitude modulation tubes are for example triodes or tetrodes while electron beam speed modulation tubes are klystrons or traveling wave tubes.
  • tetrode-type grid tubes operate at the upper limit of their frequency band with a gain of around 15 dB and an efficiency of around 50% in common amplification.
  • the efficiency considered is the ratio of the power delivered at the output during the synchronization pulse to the average power supplied to the transmitter in G standard.
  • Klystron type tubes for example, are characterized by a high gain of the order of 40 dB and by a low efficiency of the order of 25% by taking the same criteria.
  • IOT Inductive Output Tube
  • This tube includes an electron gun with a cathode, an anode and a modulation grid.
  • a modulation voltage is applied between the grid and the cathode through a resonant input cavity tuned to a desired frequency.
  • the electrons generated by the cathode emerge from the grid in packets and converge on the axis of the beam.
  • the beam then passes through an output resonant cavity.
  • the beam electrons give up their energy to the exit cavity. This energy is extracted by coupling and directed to a user device such as an antenna.
  • the electrons are collected in a collector downstream of the outlet cavity.
  • This tube has an axial structure like the klystron and not a radial structure like the tetrode. This axial structure and the nature of the materials used significantly limit the performance of the IOT.
  • the cathode used in IOTs as in klystrons is generally made of porous tungsten impregnated with barium aluminates. This cathode operates around 1020 ° C. At this temperature, the barium evaporates and settles on the grid which in turn becomes emissive. The emitted electron beam is disturbed and the life of the tube is greatly reduced. This lifespan can be of the order of 600 hours, whereas one could expect a lifespan of around 25,000 hours.
  • the operating temperature of the cathode can be reduced, but the density of current emitted and therefore the power of the IOT is limited. If we want to increase the density of the emitted current, we would have to increase the surface of the cathode.
  • the cathode and the grid are hemispherical. When the grid is large, we observe a non-uniform temperature of its bars: they are much hotter in the center than at the periphery because they cool by conduction. The hot part of the grid emits, the electron beam is then disturbed and the lifetime is reduced. All the solutions proposed each have their drawbacks and they lead in all cases to a limitation of the power of the IOT.
  • the present invention proposes to produce an electronic vacuum tube which can operate with a satisfactory lifetime at high power.
  • the technical problem is solved by the electronic tube according to claim 1.
  • This tube instead of having an axial structure has a radial structure.
  • the electron beam emitted is no longer linear but has the shape of a flat radial sheet.
  • the tube according to the invention comprises a cathode emitting electrons through a grid towards a collector, means for focusing the electrons and an output cavity coupled to the beam to take electromagnetic energy therefrom.
  • the cathode is generally with symmetry of revolution about an axis, the electron beam is radial and is focused by the focusing means in a plane substantially normal to the axis of symmetry of the cathode.
  • the outlet cavity is coaxial with the cathode.
  • the cathode can be cylindrical or in a torus portion. It is advantageously made of thoriated tungsten.
  • a grid surrounds the cathode to modulate the emission of electrons.
  • the cathode-grid space is part of a resonant modulation cavity into which a modulation voltage is injected.
  • the focusing means can be poloidal coils or permanent magnets. They are located on either side of the beam plane.
  • the collector is mounted coaxially around the axis of the cathode. He may be depressed.
  • a series of radial fins normal to the plane of the beam can be mounted between the cathode and the first resonant cavity reached by the beam.
  • Another series of fins can be provided before the collector.
  • the fins of a series are preferably in an odd number.
  • Means are provided to avoid a collision between the electrons and the fins.
  • At least one of the resonant cavities can be coupled to an auxiliary cavity.
  • One or more resonant cavities can be tunable in frequency.
  • FIG. 1 schematically represents an electronic tube according to the invention.
  • This tube has a symmetry of revolution around an axis XX '.
  • a cathode 1 which emits electrons and around a grid 2.
  • the space between the cathode 1 and the grid 2 is part of a resonant modulation cavity 3.
  • a voltage modulation 5 is applied in the resonant modulation cavity 3.
  • the modulation resonant cavity 3 is dimensioned in ⁇ / 4 or 3 ⁇ / 4. ( ⁇ represents the resonance wavelength of the cavity).
  • a tuning piston 4 can be used to tune the resonant modulation cavity 3 to a desired frequency. This piston 4 is located overall at a voltage node of the resonant circuit thus formed.
  • the cathode 1 can be produced with a mesh of thoriated tungsten heated directly or indirectly.
  • Grid 2 can be made of pyrolitic graphite. These elements are comparable to those used in conventional tetrodes. The pollution of the grid that was observed in the IOTs is thus eliminated.
  • the grid 2 and the cathode 1 can be conventionally cylindrical. To facilitate focusing of the emitted electron beam, it is conceivable that the cathode 1 and the grid 2 have the shape of a concave portion of a torus. This variant is shown in FIG. 2. The fact of using a cylindrical or toroidal cathode makes it possible to produce a cathode of large area and therefore to produce a power tube.
  • the cathode 1 and the grid 2 are generally brought to a negative high voltage.
  • the cathode 1 emits electrons radially with respect to the axis XX '.
  • the electrons grouped in packets form a radial beam t3.
  • This beam 13 is attracted to an anode 6 brought to a less negative potential than that of the cathode 1.
  • the anode 6 is formed by two rings located on either side of the plane of the electron beam. Focusing means are provided so that the beam is concentrated in a plane normal to the axis XX 'of the cathode.
  • These focusing means are first of all the electrostatic optics of the grid. To improve the concentration of electrons, it is possible to provide poloidal coils 7 or permanent magnets on either side of the plane of the electron beam. The thickness of the electron beam measured along the axis XX 'is less than the emissive height of the cathode 1.
  • the electron beam 13 then passes through an output resonant coaxial cavity 8.
  • the two rings of the anode 6 form a sliding space 14 which penetrates into the cavity 8.
  • the interior of the cavity 8 is coupled to the electron beam 13 by annular coupling openings 9. These openings, two in number, are located on either side of the plane of the electron beam 13.
  • the electrons exit the decelerated exit cavity and are collected in a collector 10 coaxial with the axis XX ', in the form of for example.
  • This collector 10 will preferably be cooled, for example, by forced ventilation or by circulation of a fluid.
  • the output cavity 8 resonates on a frequency which can be adjusted by means of a tuning device 11.
  • these are two movable pistons 11 parallel to the plane of the beam located on either side of the plane of the electron beam.
  • the outlet cavity 8 is preferably dimensioned in ⁇ / 2, that is to say that the pistons are spaced by ⁇ / 2 and are located on a tension node.
  • the electron beam is located at a voltage belly. There is then as good a coupling as possible between the cavity and the beam.
  • the electron beam gives up energy to the output cavity 8 and this energy is extracted by appropriate means. It can be a pallet 12 as in FIG. 1. This energy is transmitted to a user device such as an antenna for example.
  • the outlet cavity 8 is coupled to an auxiliary cavity 20.
  • the coupling between the two cavities can be capacitive as in FIG. 2 or inductive.
  • the energy is extracted at the level of the auxiliary cavity 20.
  • the auxiliary cavity will preferably be dimensioned in ⁇ / 2 and the energy will be extracted near a tension belly if the coupling output is capacitive.
  • radial fins 22 may be desirable to stiffen the mechanical structure of the tube and to limit the occurrence of parasitic oscillations in guided mode to divide the space between the cathode 1 and the outlet cavity 9 by radial fins 22 substantially normal to the plane of the beam 13. Their number will preferably be odd, for example three, five or more. So that these fins 22 are not bombarded by the electrons of the beam 13, we will arrange for the cathode 1 to have non-emissive zones opposite the radial fins. He can be interesting also to place radial fins 23 between the outlet cavity 8 and the manifold 10. These fins 23 will preferably be aligned with those located between the cathode 1 and the outlet cavity 8. These fins 22, 23 will advantageously be made of metal .
  • an electrically insulating part 24 for mechanically holding the anode 6 and the grid 2 while electrically insulating them.
  • the anode 6 as well as the outlet cavity 8 are generally brought to ground.
  • This part 24 is here conical in shape and can be made of ceramic.
  • the interior of the tube is conventionally subjected to vacuum. Sealing can be ensured inside the outlet cavity by two annular windows 25 located on either side of the plane of the electron beam 13. These windows 25 allow electromagnetic energy but not air to pass .
  • the collector 10 can be of the depressed type. This means that it is brought to a potential intermediate between the potential of the output cavity 8 and the potential of the cathode 1. Annular ceramic pieces 26 are provided to electrically isolate the collector 10 from the output cavity 8. In decreasing the potential of the collector compared to that of the outlet cavity, the speed of the electrons entering the collector and therefore the density of heat to be evacuated through the wall of the collector is reduced.
  • the tube according to the invention can provide significant power since the cathode can have a large emissive surface.
  • the electron beam instead of being long and thin, substantially cylindrical as in klystrons and IOTs, is now radial, substantially disc-shaped.
  • the electrons generated by the cathode diverge in the plane of the disc.
  • the electron density decreases with distance from the cathode. Due to the low density beam, the coupling with the output cavity is improved and the collector is subjected to a reduced power density.
  • the collector can work reliably with air cooling.
  • the coaxial IOT type tubes used in television transmitters have a collector whose surface is limited. This collector can be cooled by air circulation.
  • the density of thermal power to be dissipated being very high, degassing occurs which influences the life of the tube.
  • the coaxial collector of the tube according to the invention has a much larger surface area and the reliability of the tube is increased even with air cooling.

Landscapes

  • Microwave Tubes (AREA)

Description

La présente invention concerne les tubes électroniques à vide utilisés notamment en tant qu'amplificateurs de puissance dans la bande UHF.The present invention relates to electronic vacuum tubes used in particular as power amplifiers in the UHF band.

Les tubes électroniques à vide utilisés couramment en tant qu'amplificateurs de puissance sont de deux types : le premier type comprend les tubes à modulation d'amplitude du faisceau d'électrons et le deuxième type comprend les tubes à modulation de vitesse du faisceau d'électrons.There are two types of electronic vacuum tubes commonly used as power amplifiers: the first type includes electron beam amplitude modulation tubes and the second type includes electron beam speed modulation tubes electrons.

Les tubes à modulation d'amplitude sont par exemple des triodes ou des tétrodes alors que les tubes à modulation de vitesse du faisceau d'électrons sont des klystrons ou des tubes à ondes progressives.Amplitude modulation tubes are for example triodes or tetrodes while electron beam speed modulation tubes are klystrons or traveling wave tubes.

En télévision, dans la bande UHF les tubes à grilles de type tétrode fonctionnent à la limite supérieure de leur bande de fréquence avec un gain de l'ordre de 15 dB et un rendement de l'ordre de 50 % en amplification commune. Le rendement considéré est le rapport de la puissance délivrée en sortie pendant l'impulsion de synchronisation sur la puissance moyenne fournie à l'émetteur en norme G.In television, in the UHF band, tetrode-type grid tubes operate at the upper limit of their frequency band with a gain of around 15 dB and an efficiency of around 50% in common amplification. The efficiency considered is the ratio of the power delivered at the output during the synchronization pulse to the average power supplied to the transmitter in G standard.

Les tubes de type klystron, par exemple, sont caractérisés par un gain élevé de l'ordre de 40 dB et par un rendement faible de l'ordre de 25 % en prenant les mêmes critères.Klystron type tubes, for example, are characterized by a high gain of the order of 40 dB and by a low efficiency of the order of 25% by taking the same criteria.

Des travaux commencés dans les années 30 ont été réactivés ces dernières années pour développer un tube amplificateur qui permettrait en théorie d'obtenir un gain compris entre celui des klystrons et celui des tétrodes et un rendement du même ordre que celui des tétrodes grâce à un fonctionnement en classe B. Ce type de tube est connu sous le nom de klystrode et décrit dans l'ouvrage "Microwave tubes" de A.S Gilmour, Jr. page 196 ou sous le nom d'IOT (de la dénomination anglaise Inductive Output Tube), voir notamment dans la Revue Technique de THOMSON-CSF, volume 23, n°4, décembre 1991, page 810. Dans la suite de la description, ce type de tube est appelé IOT. Un IOT possède un faisceau électronique axial. Il utilise en entrée le principe de la modulation d'amplitude et en sortie la structure axiale des tubes à modulation de vitesse.Work started in the 1930s has been reactivated in recent years to develop an amplifier tube which would theoretically allow a gain between that of klystrons and that of tetrodes and a yield of the same order as that of tetrodes thanks to an operation in class B. This type of tube is known under the name of klystrode and described in the work "Microwave tubes" of AS Gilmour, Jr. page 196 or under the name of IOT (from the English name Inductive Output Tube), see especially in the THOMSON-CSF Technical Review, volume 23, n ° 4, December 1991, page 810. In the following description, this type of tube is called IOT. An IOT has an axial electron beam. It uses the principle of amplitude modulation as input and the axial structure of the speed modulation tubes as output.

Ce tube comporte un canon à électrons avec une cathode, une anode et une grille de modulation. Une tension de modulation est appliquée entre la grille et la cathode grâce à une cavité résonante d'entrée accordée sur une fréquence désirée. Les électrons générés par la cathode émergent de la grille en paquets et convergent sur l'axe du faisceau. Le faisceau traverse alors une cavité résonante de sortie. Les électrons du faisceau cèdent leur énergie à la cavité de sortie. Cette énergie est extraite par couplage et dirigée vers un dispositif utilisateur tel qu'une antenne. Les électrons sont recueillis dans un collecteur en aval de la cavité de sortie.This tube includes an electron gun with a cathode, an anode and a modulation grid. A modulation voltage is applied between the grid and the cathode through a resonant input cavity tuned to a desired frequency. The electrons generated by the cathode emerge from the grid in packets and converge on the axis of the beam. The beam then passes through an output resonant cavity. The beam electrons give up their energy to the exit cavity. This energy is extracted by coupling and directed to a user device such as an antenna. The electrons are collected in a collector downstream of the outlet cavity.

Ce tube a une structure axiale comme le klystron et non une structure radiale comme la tétrode. Cette structure axiale ainsi que la nature des matériaux utilisés limitent de manière importante les performances de l'IOT.This tube has an axial structure like the klystron and not a radial structure like the tetrode. This axial structure and the nature of the materials used significantly limit the performance of the IOT.

La cathode utilisée dans les IOTs comme dans les klystrons est généralement en tungstène poreux imprégné d'aluminates de barium. Cette cathode fonctionne aux alentours de 1 020 °C. A cette température, le barium s'évapore et se dépose sur la grille qui devient à son tour émissive. Le faisceau d'électrons émis est perturbé et la durée de vie du tube est fortement réduite. Cette durée de vie peut être de l'ordre de 600 heures alors que l'on pourrait s'attendre à une durée de vie de l'ordre de 25 000 heures.The cathode used in IOTs as in klystrons is generally made of porous tungsten impregnated with barium aluminates. This cathode operates around 1020 ° C. At this temperature, the barium evaporates and settles on the grid which in turn becomes emissive. The emitted electron beam is disturbed and the life of the tube is greatly reduced. This lifespan can be of the order of 600 hours, whereas one could expect a lifespan of around 25,000 hours.

Pour essayer de remédier à ces inconvénients liés à l'émissivité de la grille, on peut réduire la température de fonctionnement de la cathode mais on limite alors la densité de courant émis et en conséquence la puissance de l'IOT. Si l'on veut augmenter la densité de courant émis il faudrait augmenter la surface de la cathode. La cathode et la grille sont hémisphériques. Lorsque la grille est de grande taille, on observe alors une non-uniformité de température de ses barreaux : ils sont beaucoup plus chauds au centre qu'à la périphérie car ils se refroidissent par conduction. La partie chaude de la grille émet, le faisceau d'électrons est alors perturbé et la durée de vie est réduite. Toutes les solutions proposées ont chacune leurs inconvénients et elles conduisent dans tous les cas à une limitation de la puissance de l'IOT.To try to remedy these drawbacks linked to the emissivity of the grid, the operating temperature of the cathode can be reduced, but the density of current emitted and therefore the power of the IOT is limited. If we want to increase the density of the emitted current, we would have to increase the surface of the cathode. The cathode and the grid are hemispherical. When the grid is large, we observe a non-uniform temperature of its bars: they are much hotter in the center than at the periphery because they cool by conduction. The hot part of the grid emits, the electron beam is then disturbed and the lifetime is reduced. All the solutions proposed each have their drawbacks and they lead in all cases to a limitation of the power of the IOT.

La présente invention propose de réaliser un tube électronique à vide qui peut fonctionner avec une durée de vie satisfaisante à puissance élevée. Le problème technique est résolu par le tube électronique selon la revendication 1.The present invention proposes to produce an electronic vacuum tube which can operate with a satisfactory lifetime at high power. The technical problem is solved by the electronic tube according to claim 1.

Ce tube au lieu d'avoir une structure axiale a une structure radiale. Le faisceau d'électrons émis n'est plus linéaire mais a la forme d'une nappe plane radiale.This tube instead of having an axial structure has a radial structure. The electron beam emitted is no longer linear but has the shape of a flat radial sheet.

Le tube selon l'invention comporte une cathode émettant des électrons à travers une grille vers un collecteur, des moyens de focalisation des électrons et une cavité de sortie couplée au faisceau pour en prélever de l'énergie électromagnétique.The tube according to the invention comprises a cathode emitting electrons through a grid towards a collector, means for focusing the electrons and an output cavity coupled to the beam to take electromagnetic energy therefrom.

La cathode est globalement à symétrie de révolution autour d'un axe, le faisceau d'électrons est radial et est focalisé par les moyens de focalisation dans un plan sensiblement normal à l'axe de symétrie de la cathode. La cavité de sortie est coaxiale avec la cathode.The cathode is generally with symmetry of revolution about an axis, the electron beam is radial and is focused by the focusing means in a plane substantially normal to the axis of symmetry of the cathode. The outlet cavity is coaxial with the cathode.

La cathode peut être cylindrique ou en portion de tore. Elle est avantageusement en tungstène thorié. Une grille entoure la cathode pour moduler l'émission d'électrons. L'espace cathode-grille fait partie d'une cavité résonante de modulation dans laquelle une tension de modulation est injectée.The cathode can be cylindrical or in a torus portion. It is advantageously made of thoriated tungsten. A grid surrounds the cathode to modulate the emission of electrons. The cathode-grid space is part of a resonant modulation cavity into which a modulation voltage is injected.

Les moyens de focalisation peuvent être des bobines poloïdales ou des aimants permanents. Ils sont situés de part et d'autre du plan du faisceau. Le collecteur est monté coaxialement autour de l'axe de la cathode. Il peut être dépressé. Une série d'ailettes radiales normales au plan du faisceau peut être montée entre la cathode et la première cavité résonante atteinte par le faisceau.The focusing means can be poloidal coils or permanent magnets. They are located on either side of the beam plane. The collector is mounted coaxially around the axis of the cathode. He may be depressed. A series of radial fins normal to the plane of the beam can be mounted between the cathode and the first resonant cavity reached by the beam.

Une autre série d'ailettes peut être prévue avant le collecteur. Les ailettes d'une série sont de préférence en nombre impair. Des moyens sont prévus pour éviter une collision entre les électrons et les ailettes. Au moins une des cavités résonantes peut être couplée à une cavité auxiliaire.Another series of fins can be provided before the collector. The fins of a series are preferably in an odd number. Means are provided to avoid a collision between the electrons and the fins. At least one of the resonant cavities can be coupled to an auxiliary cavity.

Une ou plusieurs cavités résonantes peuvent être accordables en fréquence.One or more resonant cavities can be tunable in frequency.

D'autres caractéristiques et avantages de la présente invention apparaîtront à la lecture de la description faite ci-après, illustrée par les dessins annexés qui représentent:

  • la figure 1, une vue schématique d'un tube selon l'invention ;
  • la figure 2, une variante d'un tube selon l'invention .
Other characteristics and advantages of the present invention will appear on reading the description given below, illustrated by the appended drawings which represent:
  • Figure 1, a schematic view of a tube according to the invention;
  • Figure 2, a variant of a tube according to the invention.

Sur ces figures, les mêmes éléments portent les mêmes références. Pour des raisons de clarté, les côtes ne sont pas respectées.In these figures, the same elements have the same references. For reasons of clarity, the ribs are not respected.

La figure 1 représente schématiquement un tube électronique selon l'invention.FIG. 1 schematically represents an electronic tube according to the invention.

Ce tube a une symétrie de révolution autour d'un axe XX'. On voit, montés coaxialement autour de l'axe XX', une cathode 1 qui émet des électrons et autour une grille 2. L'espace entre la cathode 1 et la grille 2 fait partie d'une cavité résonante de modulation 3. Une tension de modulation 5 est appliquée dans la cavité résonante de modulation 3. En général, la cavité résonante de modulation 3 est dimensionnée en λ/4 ou en 3λ/4.(λ représente la longueur d'onde de résonance de la cavité). Un piston d'accord 4 peut permettre d'accorder la cavité résonante de modulation 3 sur une fréquence désirée. Ce piston 4 est situé globalement à un noeud de tension du circuit résonant ainsi formé.This tube has a symmetry of revolution around an axis XX '. We see, mounted coaxially around the axis XX ', a cathode 1 which emits electrons and around a grid 2. The space between the cathode 1 and the grid 2 is part of a resonant modulation cavity 3. A voltage modulation 5 is applied in the resonant modulation cavity 3. In general, the modulation resonant cavity 3 is dimensioned in λ / 4 or 3λ / 4. (λ represents the resonance wavelength of the cavity). A tuning piston 4 can be used to tune the resonant modulation cavity 3 to a desired frequency. This piston 4 is located overall at a voltage node of the resonant circuit thus formed.

La cathode 1 peut être réalisée avec un maillage de tungstène thorié chauffé directement ou indirectement. La grille 2 peut être en graphite pyrolitique. Ces éléments sont comparables à ceux utilisés dans les tétrodes classiques. La pollution de la grille que l'on observait dans les IOTs est ainsi éliminée.The cathode 1 can be produced with a mesh of thoriated tungsten heated directly or indirectly. Grid 2 can be made of pyrolitic graphite. These elements are comparable to those used in conventional tetrodes. The pollution of the grid that was observed in the IOTs is thus eliminated.

La grille 2 et la cathode 1 peuvent être classiquement cylindriques. Pour faciliter la focalisation du faisceau d'électrons émis on peut envisager que la cathode 1 et la grille 2 aient une forme de portion concave de tore. Cette variante est représentée sur la figure 2. Le fait d'utiliser une cathode cylindrique ou en portion de tore permet de réaliser une cathode de grande surface et donc de produire un tube de puissance.The grid 2 and the cathode 1 can be conventionally cylindrical. To facilitate focusing of the emitted electron beam, it is conceivable that the cathode 1 and the grid 2 have the shape of a concave portion of a torus. This variant is shown in FIG. 2. The fact of using a cylindrical or toroidal cathode makes it possible to produce a cathode of large area and therefore to produce a power tube.

La cathode 1 et la grille 2 sont généralement portées à une haute tension négative.The cathode 1 and the grid 2 are generally brought to a negative high voltage.

La cathode 1 émet des électrons radialement par rapport à l'axe XX'. A la sortie de la grille 2, les électrons regroupés en paquets forment un faisceau t3 radial. Ce faisceau 13 est attiré vers une anode 6 portée à un potentiel moins négatif que celui de la cathode 1. L'anode 6 est formée de deux anneaux situés de part et d'autre du plan du faisceau d'électrons. Des moyens de focalisation sont prévus pour que le faisceau soit concentré dans un plan normal à l'axe XX' de la cathode.The cathode 1 emits electrons radially with respect to the axis XX '. At the exit of the grid 2, the electrons grouped in packets form a radial beam t3. This beam 13 is attracted to an anode 6 brought to a less negative potential than that of the cathode 1. The anode 6 is formed by two rings located on either side of the plane of the electron beam. Focusing means are provided so that the beam is concentrated in a plane normal to the axis XX 'of the cathode.

Ces moyens de focalisation sont d'abord l'optique électrostatique de la grille. Pour améliorer la concentration des électrons on peut prévoir des bobines 7 poloïdales ou des aimants permanents de part et d'autre du plan du faisceau d'électrons. L'épaisseur du faisceau d'électrons mesurée le long de l'axe XX' est plus faible que la hauteur émissive de la cathode 1.These focusing means are first of all the electrostatic optics of the grid. To improve the concentration of electrons, it is possible to provide poloidal coils 7 or permanent magnets on either side of the plane of the electron beam. The thickness of the electron beam measured along the axis XX 'is less than the emissive height of the cathode 1.

Le faisceau d'électrons 13 traverse ensuite une cavité coaxiale résonante 8 de sortie. Les deux couronnes de l'anode 6 forment un espace de glissement 14 qui pénètre dans la cavité 8. L'intérieur de la cavité 8 est couplé au faisceau d'électrons 13 par des ouvertures 9 de couplage annulaires. Ces ouvertures, au nombre de deux, sont situées de part et d'autre du plan du faisceau d'électrons 13. Les électrons sortent de la cavité de sortie décélérés et sont recueillis dans un collecteur 10 coaxial avec l'axe XX', en forme de par exemple. Ce collecteur 10 sera de préférence refroidi, par exemple, par ventilation forcée ou par circulation d'un fluide.The electron beam 13 then passes through an output resonant coaxial cavity 8. The two rings of the anode 6 form a sliding space 14 which penetrates into the cavity 8. The interior of the cavity 8 is coupled to the electron beam 13 by annular coupling openings 9. These openings, two in number, are located on either side of the plane of the electron beam 13. The electrons exit the decelerated exit cavity and are collected in a collector 10 coaxial with the axis XX ', in the form of for example. This collector 10 will preferably be cooled, for example, by forced ventilation or by circulation of a fluid.

La cavité de sortie 8 résonne sur une fréquence qui peut être ajustée grâce à un dispositif d'accord 11. Sur la figure 1, il s'agit de deux pistons mobiles 11 parallèles au plan du faisceau situés de part et d'autre du plan du faisceau d'électrons. La cavité 8 de sortie est de préférence dimensionnée en λ/2, c'est-à-dire que les pistons sont espacés de λ/2 et sont situés sur un noeud de tension. Le faisceau d'électrons est situé lui à un ventre de tension. Il y a alors un couplage aussi bon que possible entre la cavité et le faisceau.The output cavity 8 resonates on a frequency which can be adjusted by means of a tuning device 11. In FIG. 1, these are two movable pistons 11 parallel to the plane of the beam located on either side of the plane of the electron beam. The outlet cavity 8 is preferably dimensioned in λ / 2, that is to say that the pistons are spaced by λ / 2 and are located on a tension node. The electron beam is located at a voltage belly. There is then as good a coupling as possible between the cavity and the beam.

Le faisceau d'électrons cède de l'énergie à la cavité de sortie 8 et cette énergie est extraite par des moyens appropriés. Il peut s'agir d'une palette 12 comme sur la figure 1. Cette énergie est transmise à un dispositif utilisateur tel qu'une antenne par exemple.The electron beam gives up energy to the output cavity 8 and this energy is extracted by appropriate means. It can be a pallet 12 as in FIG. 1. This energy is transmitted to a user device such as an antenna for example.

On peut envisager, en vue d'augmenter la bande passante du tube, que la cavité de sortie 8 soit couplée à une cavité auxiliaire 20. Le couplage entre les deux cavités peut être capacitif comme sur la figure 2 ou inductif. Sur la figure 2, l'énergie est extraite au niveau de la cavité auxiliaire 20. La cavité auxiliaire sera de préférence dimensionnée en λ/2 et l'extraction de l'énergie se fera à proximité d'un ventre de tension si le couplage de sortie est capacitif.It can be envisaged, with a view to increasing the bandwidth of the tube, that the outlet cavity 8 is coupled to an auxiliary cavity 20. The coupling between the two cavities can be capacitive as in FIG. 2 or inductive. In FIG. 2, the energy is extracted at the level of the auxiliary cavity 20. The auxiliary cavity will preferably be dimensioned in λ / 2 and the energy will be extracted near a tension belly if the coupling output is capacitive.

Il peut être souhaitable pour rigidifier la structure mécanique du tube et pour limiter la naissance d'oscillations parasites en mode guidé de diviser l'espace situé entre la cathode 1 et la cavité de sortie 9 par des ailettes radiales 22 sensiblement normales au plan du faisceau 13. Leur nombre sera de préférence impair par exemple trois, cinq ou plus. Afin que ces ailettes 22 ne soient pas bombardées par les électrons du faisceau 13 on s'arrangera pour que la cathode 1 comporte des zones non émissives en face des ailettes radiales. Il peut être intéressant de placer également des ailettes radiales 23 entre la cavité de sortie 8 et le collecteur 10. Ces ailettes 23 seront de préférence alignées avec celles situées entre la cathode 1 et la cavité de sortie 8. Ces ailettes 22, 23 seront avantageusement réalisées en métal.It may be desirable to stiffen the mechanical structure of the tube and to limit the occurrence of parasitic oscillations in guided mode to divide the space between the cathode 1 and the outlet cavity 9 by radial fins 22 substantially normal to the plane of the beam 13. Their number will preferably be odd, for example three, five or more. So that these fins 22 are not bombarded by the electrons of the beam 13, we will arrange for the cathode 1 to have non-emissive zones opposite the radial fins. He can be interesting also to place radial fins 23 between the outlet cavity 8 and the manifold 10. These fins 23 will preferably be aligned with those located between the cathode 1 and the outlet cavity 8. These fins 22, 23 will advantageously be made of metal .

On peut prévoir comme sur la figure 2, une pièce 24 électriquement isolante pour maintenir mécaniquement l'anode 6 et la grille 2 tout en les isolant électriquement. L'anode 6 tout comme la cavité de sortie 8 sont généralement portées à une masse. Cette pièce 24 est ici de forme conique et peut être en céramique.One can provide as in Figure 2, an electrically insulating part 24 for mechanically holding the anode 6 and the grid 2 while electrically insulating them. The anode 6 as well as the outlet cavity 8 are generally brought to ground. This part 24 is here conical in shape and can be made of ceramic.

L'intérieur du tube est classiquement soumis au vide. L'étanchéité peut être assurée à l'intérieur de la cavité de sortie par deux fenêtres 25 annulaires situées de part et d'autre du plan du faisceau d'électrons 13. Ces fenêtres 25 laissent passer l'énergie électromagnétique mais pas l'air.The interior of the tube is conventionally subjected to vacuum. Sealing can be ensured inside the outlet cavity by two annular windows 25 located on either side of the plane of the electron beam 13. These windows 25 allow electromagnetic energy but not air to pass .

Le collecteur 10 peut être de type dépressé. Cela signifie qu'il est porté à un potentiel intermédiaire entre le potentiel de la cavité de sortie 8 et le potentiel de la cathode 1. Des pièces de céramique 26 annulaires sont prévues pour isoler électriquement le collecteur 10 de la cavité de sortie 8. En diminuant le potentiel du collecteur par rapport à celui de la cavité de sortie on réduit la vitesse des électrons en entrée du collecteur et donc la densité de chaleiir à évacuer par la paroi du collecteur.The collector 10 can be of the depressed type. This means that it is brought to a potential intermediate between the potential of the output cavity 8 and the potential of the cathode 1. Annular ceramic pieces 26 are provided to electrically isolate the collector 10 from the output cavity 8. In decreasing the potential of the collector compared to that of the outlet cavity, the speed of the electrons entering the collector and therefore the density of heat to be evacuated through the wall of the collector is reduced.

Le tube selon l'invention peut fournir une puissance importante car la cathode peut avoir une grande surface émissive.The tube according to the invention can provide significant power since the cathode can have a large emissive surface.

Le fait de pouvoir utiliser une cathode en tungstène thorié permet d'éliminer les problèmes de pollution de la grille, problèmes existants avec les cathodes imprégnées.The fact of being able to use a thoriated tungsten cathode makes it possible to eliminate the problems of pollution of the grid, problems existing with impregnated cathodes.

Le faisceau d'électrons au lieu d'être long et fin sensiblement cylindrique comme dans les klystrons et IOTs est maintenant radial, sensiblement en forme de disque. Les électrons générés par la cathode divergent dans le plan du disque. La densité électronique décroît en s'éloignant de la cathode. Du fait du faisceau de faible densité le couplage avec la cavité de sortie est amélioré et le collecteur est soumis à une densité de puissance réduite. Le collecteur peut fonctionner fiablement avec un refroidissement par air. Les tubes à structure coaxiale de type IOT utilisés dans les émetteurs de télévision ont un collecteur dont la surface est limitée. Ce collecteur peut être refroidi par circulation d'air. La densité de puissance thermique à dissiper étant très importante il se produit des dégazages qui influent sur la durée de vie du tube. Le collecteur coaxial du tube selon l'invention a une surface beaucoup plus grande et la fiabilité du tube est accrue même avec un refroidissement par air.The electron beam instead of being long and thin, substantially cylindrical as in klystrons and IOTs, is now radial, substantially disc-shaped. The electrons generated by the cathode diverge in the plane of the disc. The electron density decreases with distance from the cathode. Due to the low density beam, the coupling with the output cavity is improved and the collector is subjected to a reduced power density. The collector can work reliably with air cooling. The coaxial IOT type tubes used in television transmitters have a collector whose surface is limited. This collector can be cooled by air circulation. The density of thermal power to be dissipated being very high, degassing occurs which influences the life of the tube. The coaxial collector of the tube according to the invention has a much larger surface area and the reliability of the tube is increased even with air cooling.

Claims (15)

  1. Vacuum electron tube including a cathode (1) which emits electrons through a grid (2) to a collector (10), means (7) for focusing the electrons in order to concentrate them into a beam (13), an output resonant cavity (8) coupled to the beam to draw energy from the focused beam, the space between the cathode (1) and the grid (2) forming part of an input resonant cavity (3), characterized in that the tube has a symmetry of revolution about an axis, the cathode, the grid and the output resonant cavity (8) being coaxial with the axis of symmetry, and in that the cathode emits electrons radially relative to the axis of symmetry, the substantially disc-shaped radial beam (13) being focused by focusing means (7) in a plane normal to the axis of symmetry.
  2. Electron tube according to Claim 1, characterized in that the cathode (1) is made of thoriated tungsten.
  3. Electron tube according to one of Claims 1 and 2, characterized in that the cathode (1) is cylindrical or has the shape of a portion of a torus.
  4. Electron tube according to one of Claims 1 to 3, characterized in that the focusing means (7) are located on either side of the plane of the beam.
  5. Electron tube according to one of Claims 1 to 4, characterized in that the focusing means (7) are poloidal coils or permanent magnets.
  6. Electron tube according to one of Claims 1 to 5, characterized in that the collector (10) is coaxial with the cathode.
  7. Electron tube according to one of Claims 1 to 6, characterized in that the collector (10) is depressed.
  8. Electron tube according to one of Claims 1 to 7, characterized in that a series of radial fins (22), normal to the plane of the electron beam, is arranged between the cathode (1) and the output resonant cavity (8).
  9. Electron tube according to one of Claims 1 to 8, characterized in that another series of radial fins (23), normal to the plane of the beam, is arranged between the output resonant cavity (8) and the collector (10).
  10. Electron tube according to one of Claims 8 or 9, characterized in that there is an odd number of fins in one series.
  11. Electron tube according to one of Claims 8 to 10, characterized in that means are provided for preventing collisions between the electrons and the fins.
  12. Electron tube according to one of Claims 1 to 11, characterized in that at least one of the resonant cavities (8) is coupled to an auxiliary resonant cavity (20).
  13. Electron tube according to one of Claims 1 to 12, characterized in that a frequency tuning device (11) is provided for tuning the frequency of at least one of the resonant cavities (8).
  14. Electron tube according to one of Claims 1 to 13, characterized in that the output resonant cavity is dimensioned on the basis of λ/2 (λ being the resonant wavelength in the cavity).
  15. Electron tube according to one of Claims 1 to 14, characterized in that the input resonant cavity (3) is dimensioned on the basis of λ/4 or 3λ/4 (λ being the wavelength of resonance in the cavity).
EP19930402154 1992-09-11 1993-09-03 Radial electron tube Expired - Lifetime EP0587481B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9210841A FR2695755B1 (en) 1992-09-11 1992-09-11 Electronic tube with radial structure.
FR9210841 1992-09-11

Publications (2)

Publication Number Publication Date
EP0587481A1 EP0587481A1 (en) 1994-03-16
EP0587481B1 true EP0587481B1 (en) 1997-06-04

Family

ID=9433407

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19930402154 Expired - Lifetime EP0587481B1 (en) 1992-09-11 1993-09-03 Radial electron tube

Country Status (3)

Country Link
EP (1) EP0587481B1 (en)
DE (1) DE69311238T2 (en)
FR (1) FR2695755B1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2728386B1 (en) * 1994-12-20 1997-01-24 Thomson Tubes Electroniques ELECTRONIC TUBE WITH IMPROVED PERFORMANCE GRID
US6084353A (en) * 1997-06-03 2000-07-04 Communications And Power Industries, Inc. Coaxial inductive output tube having an annular output cavity
DE10040896B4 (en) * 2000-08-18 2005-05-04 Gesellschaft für Schwerionenforschung mbH Apparatus and method for ion beam acceleration and electron beam pulse shaping and amplification
EP1203395B8 (en) * 2000-08-17 2009-08-26 GSI Helmholtzzentrum für Schwerionenforschung GmbH Device and method for ion beam acceleration and electron beam pulse formation and amplification
CN104392880B (en) * 2014-11-03 2017-05-03 中国科学院电子学研究所 Racking method of multi-channel tuning klystron resonant cavity
CN113725053B (en) * 2021-09-02 2024-03-26 中国科学院空天信息创新研究院 Plane cascade klystron

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3305752A (en) * 1963-12-06 1967-02-21 Friz Walter Fast wave crossed field travelingwave tube
US3971966A (en) * 1975-08-14 1976-07-27 The United States Of America As Represented By The Secretary Of The Army Planar ring bar travelling wave tube
US4424044A (en) * 1982-04-23 1984-01-03 Raytheon Company Method of fabricating cathode electrodes
DE3317788A1 (en) * 1983-05-16 1984-11-22 Siemens AG, 1000 Berlin und 8000 München CLYSTRODE WITH HIGH REINFORCEMENT

Also Published As

Publication number Publication date
EP0587481A1 (en) 1994-03-16
FR2695755B1 (en) 1994-10-28
DE69311238D1 (en) 1997-07-10
DE69311238T2 (en) 1997-09-18
FR2695755A1 (en) 1994-03-18

Similar Documents

Publication Publication Date Title
Kesari et al. High Power Microwave Tubes: Basics and Trends, Volume 2
FR2547456A1 (en) ELECTRON BEAM TUBE DENSITY MODULE WITH INCREASED GAIN
FR2527005A1 (en) ELECTRONIC POWER TUBE WITH PERFECTED GRID
EP0587481B1 (en) Radial electron tube
US2416302A (en) Electronic apparatus
FR2877489A1 (en) ELECTRON CANON
US3453482A (en) Efficient high power beam tube employing a fly-trap beam collector having a focus electrode structure at the mouth thereof
US3249794A (en) High frequency tube method and apparatus
US9196449B1 (en) Floating grid electron source
US3471744A (en) Coaxial magnetron having a segmented ring slot mode absorber
FR2760127A1 (en) ELECTRON CANON AND KLYSTRON COMPRISING THE SAME
US2789250A (en) High frequency device
EP1719148B1 (en) Collector arrangement
EP0251830B1 (en) Multiple beam lasertron
Roitman et al. Sub-millimeter waves from a compact, low voltage extended interaction klystron
FR2733856A1 (en) CATHODE FOR GRID ELECTRON CANON, GRID TO BE ASSOCIATED WITH SUCH A CATHODE AND ELECTRON CANON INCLUDING SUCH CATHODE
US3596131A (en) Cathode secondary emitter for crossed-field tubes
US11545329B2 (en) THz vacuum electronic devices with micro-fabricated electromagnetic circuits
FR2722559A1 (en) MICROWAVE OVEN
FR2659492A1 (en) HIGH FREQUENCY AMPLIFIER APPARATUS.
WO2009083540A1 (en) Electron tube electrode protection
US3448313A (en) Efficient radiation cooled beam collector for linear beam devices
US3448325A (en) Linear beam tube having a beam collector cooled by radiation through an infrared window
US3403352A (en) Laser having efficient coupling between a phosphor pump source and the laser medium
Naumenko Survey of existing designs of millimeter wave band magnetrons

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19940816

17Q First examination report despatched

Effective date: 19951228

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 69311238

Country of ref document: DE

Date of ref document: 19970710

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19970807

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20050902

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20060830

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20060908

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20070403

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20070903

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20080531

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20071001

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20070903