EP1145268A2 - Multiband travelling wave tube of reduced length capable of high power functioning - Google Patents

Multiband travelling wave tube of reduced length capable of high power functioning

Info

Publication number
EP1145268A2
EP1145268A2 EP99959496A EP99959496A EP1145268A2 EP 1145268 A2 EP1145268 A2 EP 1145268A2 EP 99959496 A EP99959496 A EP 99959496A EP 99959496 A EP99959496 A EP 99959496A EP 1145268 A2 EP1145268 A2 EP 1145268A2
Authority
EP
European Patent Office
Prior art keywords
section
output
signal
wave tube
traveling wave
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.)
Granted
Application number
EP99959496A
Other languages
German (de)
French (fr)
Other versions
EP1145268B1 (en
Inventor
Jean-Claude Thomson-CSF Prop. Intel. KUNTZMANN
Dominique Thomson-CSF Prop. Intell. HENRY
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
Thales Electron Devices SA
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Filing date
Publication date
Application filed by Thales Electron Devices SA filed Critical Thales Electron Devices SA
Publication of EP1145268A2 publication Critical patent/EP1145268A2/en
Application granted granted Critical
Publication of EP1145268B1 publication Critical patent/EP1145268B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps

Definitions

  • the present invention relates to a multiband traveling wave tube capable of operating at high power.
  • This tube intended in particular to be used in airborne or space applications, must be relatively short.
  • the development of techniques and the growing mastery of materials have made it possible to develop traveling wave tubes intended to operate in a very wide frequency band and which are relatively short.
  • These tubes are known by the name of mini-TOP.
  • mini-TOP are progressive wave tubes with a tight helical monobloc line. In terms of frequencies, we managed to obtain a ratio of at least three between the high frequency and the low frequency of the band.
  • these tubes do not exceed thirty centimeters but from the power point of view they hardly reach more than a few tens of watts.
  • obtaining a higher power leads to an increase in the propeller tension and an increase in its length.
  • This channel does not lead to a multiband traveling wave tube, of reduced length, capable of operating at high power.
  • the object of the present invention is a multiband traveling wave tube whose length is of the order of that of the mini-TOP but which is capable of operating at higher powers while maintaining a gain of the same order.
  • the multiband traveling wave tube comprises a microwave line traversed by electrons and in which a signal is amplified.
  • This microwave line successively comprises an input microwave line section separated from a succession of disjoint output microwave line sections, each output section working in one of the operating bands of the tube.
  • the input section is connected, at one end, to means for inputting the signal to be amplified and works in a frequency band encompassing the operating frequency bands of the tube. It is intended to preamplify the signal to be amplified.
  • the succession of output sections receives the preamplified signal, each of its output sections being intended to amplify it, if it is at a frequency included in its working frequency band and to let it pass practically without intervention, it is at a frequency outside its working frequency band, each of the output sections being connected at one end to means for outputting the preamplified signal which it has amplified.
  • the central frequencies of the working bands of the output sections decrease with their distance from the input section.
  • the microwave line sections are helical, each helix is held in a sheath by dielectric supports, the different sheaths being secured to each other.
  • the inlet section includes dispersion correction means such as valves.
  • the propeller of the first outlet section will preferably be given substantially the same length and / or the same internal diameter as that of the propeller of the inlet section.
  • the helix wire of the first outlet segment will also preferably have the same cross-section as that of the helix wire of the inlet segment.
  • the pitch of the helix of the first output section will preferably be smaller than that of the propeller of the inlet section.
  • the length and / or the pitch and / or the internal diameter of the propellers of the outlet sections will increase with their distance from the inlet section. It is the same for the section of the propeller.
  • the input section is provided with an attenuation zone at the opposite end to that connected to the input means of the signal to be amplified.
  • each output section is provided with an attenuation zone at the end opposite to that connected to the output means of the signal which it has amplified.
  • FIG. 2 an exploded schematic view of a traveling wave tube with tight propeller according to the invention
  • - Figure 4a a cross section of the first outlet section;
  • - Figures 4b, 4c respectively the normalized phase speed and the gain as a function of the frequency of the first output section of Figure 4a;
  • Figure 1 shows schematically a multiband traveling wave tube according to the invention.
  • a gun 1 to produce a beam 2 of electrons
  • a body 3 in which there is an interaction between the electron beam 2 and a signal to be amplified
  • a collector 4 to collect the electrons from the beam 2 as they exit the body 3.
  • the electron beam 2 crosses between the input 6 and the output 7 of the body 3, a microwave line 8 formed of several sections h, h1 ..., hi, ... hn of disjoint microwave lines , arranged one after the other.
  • the first section crossed by the beam 2 is a section h called input, others h1, hi, hn form a succession of so-called output sections and their number n is equal to the number of frequency bands B1 , Bi, Bn in which the tube is intended to operate, n being an integer greater than or equal to two.
  • Each of the output sections h1, ... hi, ... hn is intended to work in one of the operating bands of the tube respectively B1 ..., Bi, ... Bn.
  • Each frequency band B1 ..., Bi, ... Bn is centered on a central frequency respectively F1, Fi, Fn.
  • Each frequency band is associated with an output segment.
  • the electron beam 2 enters each of the sections h, h1, ... hi hn via an inlet end ee and leaves it through an outlet end es.
  • the input section h is intended to function as a preamplifier in a very wide band B encompassing all the bands B1, Bi, Bn of operation of the tube.
  • the input end ee of the input section h is connected to input means E of a signal to be amplified in the tube. Its outlet end is around the inlet end ee of the first outlet section h1.
  • Each output segment h1, hi, hn of the succession is intended to amplify the preamplified signal in the input segment h, if the preamplified signal is at a frequency included in its working frequency band B1, Bi, Bn.
  • the output sections h1, hi, hn have practically no action on the preamplified signal which passes through them and which is not at a frequency included in their working frequency band.
  • Each of the output ends of the output sections h1, hi, hn is connected to output means S1, Si, Sn of the preamplified signal passing through it, if the latter has been amplified in said output section h1, hi, hn .
  • the preamplified signal which traverses the first output segment h1 is amplified there, if its frequency is included in the band B1, it is then extracted by the output means S1. If the frequency of the preamplified signal is not in the band B1, the preamplified signal traverses the first output segment h1 practically, without coupling with the electron beam 2, and at the output end es of the first segment h1, it enters the second output segment h2 where it is amplified, if its frequency is in the band B2, then it is extracted. If its frequency is not in band B2, it enters the third output section h3 and so on from section to section until it is amplified in the appropriate section, then extracted.
  • a signal of frequency F propagates in the output section hi (i integer between 1 and n - 2), if it is not amplified it means that the frequency F is not included in the Bi band.
  • the frequency signal F is not extracted at the output end of the output segment hi and it then enters the next output segment hi + 1. If its frequency F is in the frequency band Bi + 1 associated with output section hi + 1, it is amplified and then extracted at the end es of said section hi + 1. If its frequency F is outside the band Bi + 1, it enters the next section hi + 2 and so on.
  • FIG. 2 shows such a tube seen from the outside but whose casing 5 is partially open so as to reveal the various sections of microwave line h, h1, h2 which are in a helix.
  • the other elements inside the envelope such as the barrel, the focusing device, the collector are not shown for the sake of clarity.
  • the propellers 20, 21, 22 each inserted into a conductive sheath 11, 11.1, 11.2 are held in the sheath 11, 11.1, 11.2 using insulating supports 12, 12.1, 12.2.
  • three insulating supports 12, 12.1, 12.2 are provided per helix (but only one is visible in FIG.
  • the supports can be conventionally made of boron nitride, alumina or beryllium oxide for example.
  • the propellers 20, 21, 22 are in contact with each other.
  • the different sleeves 11, 11.1, 11.2 are integral with each other. This connection is waterproof.
  • the input end ee of the input section h is connected to input means E of a signal to be amplified represented in the form of a coaxial line.
  • the two output sections h1, h2 work respectively in the band B1, B2, of respective central frequency F1, F2.
  • the frequency F1 is greater than the frequency F2.
  • the output end es of the section h1 is connected to output means S1 of the preamplified signal if it has been amplified by said section h1.
  • the output means S1 are represented by a waveguide which is conventional at high frequency.
  • the output end es of the section h2 is connected to output means S2 of the signal which has been amplified by the section h2. In the example it is a coaxial line. It is understood that each of the entry and exit means could be of a different nature.
  • the section h is intended to work in a very wide band B encompassing the two bands B1 and B2. We will see more precisely the characteristics of each of the line sections h, h1, h2.
  • the input segment h comprises means of dispersion correction 13 such as valves for example.
  • the valves 13 are distinct from the supports 12, these are conductors extending longitudinally along the propeller 20 and which project from the sheath 11 towards the propeller 20. These valves 13 are separated from the propeller 20 by a space 14. They are placed between the supports 12. Another type of valve can be used as shown in Figure 3b. These valves integrated into the dielectric supports are described in European patent EP-B- 0 401 065.
  • the propeller is held by the dielectric supports 120 which are in turn supported by conductive elements 130 projecting from the inner wall of the sheath 11 towards the propeller 20.
  • This configuration has the advantage of less obstructing the interior of the sheath, which makes it possible to reduce the time required for pumping and to improve the vacuum qualitatively.
  • Figures 3a and 3b show cross sections of inlet section h.
  • the internal diameter d of the propeller 20 is relatively small so that the section h can work as a preamplifier in the band B encompassing all the operating bands of the tube. This diameter depends on the frequency band to be amplified.
  • FIG. 3c is a diagram of the normalized phase speed c / v ⁇ of the signal propagating in the input section h as a function of the frequency F. It is assumed in the example described that the tube is intended to operate in two bands B1, B2 centered respectively around the frequency F0 and the frequency 3F0.
  • the normalized phase speed c / v ⁇ is the ratio of the phase speed v ⁇ to the speed of light c.
  • the solid line curve is obtained in the inlet section h with valves 13 distinct from the supports 12 and the dotted curve is that which would be obtained in the absence of the valves 13.
  • FIG. 3d is the gain G of the input section h as a function of the frequency F.
  • the maximum gain Gmax is obtained in the median part of the curve, that is to say for a median frequency, the frequencies F0 and 3F0 are located on either side of the median frequency. In the operating bands B1, B2, the gain is approximately 4 to 5 dB lower than the maximum gain.
  • the first output section h1 is the one that works in amplification at the highest frequency, here 3F0. Its operating band B1 is narrower than band B and the section h1 does not require dispersion correction means.
  • FIG. 4a shows in cross section the first output section h1 with the dielectric supports 12.1. Its propeller 21 can be made to simplify with the same wire as the propeller 20 of the inlet section h if the desired power at the outlet es of the first outlet section is not too high. It will have substantially the same internal diameter d1 as that of the propeller 20 of the inlet section h since this first outlet section h1 is associated with the band B1 whose central frequency 3F0 is the highest.
  • its pitch p1 may be smaller than that p of the propeller 20 of the input section h to maintain the synchronism between the speed of the electron beam and the speed of the signal which travels through it, synchronism acquired in the section h entry.
  • the length 11 of the propeller 21 is linked to the gain necessary to obtain the desired power at the frequency 3F0. It is desirable that the gain of the first output segment h1 be greater than that of the input segment h1. However, the length 11 of the propeller of the first outlet section h1 can be of the same order as that of the propeller 20 of the inlet section h, since the gain per unit length of a helical line without means of dispersion correction is greater than that of a helical line with dispersion correction means.
  • FIG. 4b shows the shape of the normalized phase speed as a function of the frequency for this first output segment h1 while FIG. 4c shows the shape of the gain as a function of the frequency.
  • the gain is maximum for the center frequency 3F0.
  • Figure 5a shows a cross section of the next outlet section h2 which here is the last. It is associated with the lowest central frequency band B2 F0.
  • This second outlet section h2 also does not require dispersion correction means since the strip B2 is narrower than the strip B. It would be the same for all the other outlet sections.
  • the internal diameter d2 of its propeller 22 is larger than that of the propeller 21 of the outlet section h1 which precedes it.
  • the inner diameter of the propeller varies in material substantially inversely proportional to the operating frequency so that the amplification parameter remains constant.
  • the ratio of the two diameters d1, d2 is approximately the same as that of the corresponding central frequencies 3F0, F0.
  • the internal diameter of the propellers of the outlet sections h1, h2 increases with their distance from the inlet section h. With such a configuration, the diameter of the electron beam increases the closer one gets to the collector. The focusing of the beam is therefore done conventionally for a person skilled in the art.
  • the supports 12.2 which hold the propeller 22 are adapted to the diameter of the propeller and to that of the section 11.2 of the sheath.
  • the different sections 11, 11.1, 11.2 of sheath may not have the same diameter.
  • the pitch p2 of the propeller 22 of the second output segment h2 is greater than that p1 of the output segment h1 which precedes it, still with the aim of maintaining synchronism between the speed of the electron beam and the speed of the signal which runs through the propeller 22. More generally, the pitch of the propellers of the outlet sections increases with their distance from the inlet section.
  • the signal produced by the output segment h2 has a power greater than that of the signal produced by the output segment h1 which precedes it, which leads to giving the thread of the propeller 22 a larger section than that of the propeller wire 21. It is possible to reach, at the output of the output segment h2, powers three to four times greater than those obtained at the output of the output segment h1. By generalizing, the section of the wire of the propellers of the output sections will increase with their distance from the input section.
  • the length 12 of the propeller 22 is related to the gain necessary to obtain the desired power at the frequency F0.
  • the section h2 will be given a length 12 greater than that 11 of the outlet section h1 which precedes it because the frequency at which it works is lower. More generally in succession, the length of the propellers of the outlet sections increases with their distance from the inlet section.
  • FIG. 5b shows the shape of the normalized phase speed as a function of the frequency for this second output section h2 while FIG. 5c shows the shape of its gain as a function of the frequency. The gain is maximum for the central frequency F0.
  • an attenuation zone 30, 31, 32 is provided at the sections h, h1, h2 of the microwave line. More precisely, these attenuation zones cover the supports 12, 12.1, 12.2 of the propellers 20, 21, 22. These attenuation zones can be produced by a carbon deposit for example. These attenuation zones are located respectively the first 30 near the outlet end es of the inlet section h and the other 31, 32 near the inlet end ee of the respective outlet sections h1, h2 .
  • the attenuation zone 31 of the first outlet section h1 has approximately the same length as that of the inlet section h.
  • the attenuation zone 32 of another outlet section h2 is longer than that 31 of the outlet section h1 which precedes it.
  • FIG. 6 shows the shape of the power P (expressed in dBm) of a signal injected with an amplitude Pe into the tube of FIG. 2 and which traverses the microwave line until it is extracted, ie at the level of the means of output S1, ie at the output means S2.
  • the signal extracted at the output means S1 has an amplitude power P1 and is at the frequency 3F0.
  • the signal extracted at the output means S2 has a power P2 and is at a frequency F0.
  • the amplitude P2 is approximately three times greater than the amplitude P1.
  • the powers drop sharply at the level of the attenuation zones 30, 31, 32 which are symbolized by triangles.
  • the signal which is amplified therein has its amplitude which increases strongly as soon as it propagates beyond the corresponding attenuation zone 31, 32.

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  • Microwave Amplifiers (AREA)
  • Microwave Tubes (AREA)

Abstract

The invention concerns a travelling wave tube designed to operate as amplifier in several frequency bands (B1, Bi, Bn), comprising a microwave frequency line (8) carrying electrons and wherein a signal is amplified. The microwave frequency line successively comprises an input section (h) separated by a series of disjointed output sections (h1, hi, hn), each output section operating in one of the tube operating frequency bands. The input section (h), connected at one end (ee) to input means (E) for the signal to be amplified, operates in a frequency band (B) including the tube operating frequency bands (B1, Bi, Bn) and is designed to preamplify the signal to be amplified. The series of output sections (h1, hi, hn) receives the preamplified signal. Each of the output sections is designed to amplify it if the signal is at a frequency included in its operating frequency band, and to allow it to pass almost without intervening, if it is at a frequency outside its operating frequency band. Each of the output sections (h1, hi, hn) is connected at one output end (es) to output means (h1, hi, hn) for the preamplified signal which it has amplified. The invention is applicable to travelling wave tubes with reduced length capable high power functioning.

Description

TUBE A ONDES PROGRESSIVES MULTIBANDE DE LONGUEUR REDUITE CAPABLE DE FONCTIONNER A PUISSANCE ELEVEE MULTIBAND PROGRESSIVE WAVE TUBE OF REDUCED LENGTH CAPABLE OF OPERATING AT HIGH POWER
La présente invention est relative à un tube à ondes progressives multibande capable de fonctionner à puissance élevée. Ce tube destiné notamment à être utilisé dans des applications aéroportées ou spatiales, doit être relativement court. Le développement des techniques et la maîtrise croissante des matériaux ont permis de mettre au point des tubes à ondes progressives destinés à fonctionner dans une très large bande de fréquences et qui sont relativement courts. Ces tubes sont connus sous la dénomination de mini- TOP. Ce sont des tubes à ondes progressives à ligne monobloc en hélice serrée. Au point de vue fréquences, on est arrivé à obtenir un rapport d'au moins trois entre la fréquence haute et la fréquence basse de la bande.The present invention relates to a multiband traveling wave tube capable of operating at high power. This tube intended in particular to be used in airborne or space applications, must be relatively short. The development of techniques and the growing mastery of materials have made it possible to develop traveling wave tubes intended to operate in a very wide frequency band and which are relatively short. These tubes are known by the name of mini-TOP. These are progressive wave tubes with a tight helical monobloc line. In terms of frequencies, we managed to obtain a ratio of at least three between the high frequency and the low frequency of the band.
Au point de vue dimensions, ces tubes ne dépassent pas la trentaine de centimètres mais au point de vue puissance ils n'atteignent guère plus que quelques dizaines de watts. On aurait pu penser extrapoler ces tubes pour augmenter leur puissance. Mais, pour un gain donné, l'obtention d'une puissance plus élevée entraîne une augmentation de la tension d'hélice et une augmentation de sa longueur. Or, il n'est pas question de diminuer le gain, de manière à obtenir la puissance requise sans augmenter la longueur de l'hélice. Cette voie ne conduit pas un tube à ondes progressives multibande, de longueur réduite, capable de fonctionner à puissance élevée.From the dimensional point of view, these tubes do not exceed thirty centimeters but from the power point of view they hardly reach more than a few tens of watts. One would have thought to extrapolate these tubes to increase their power. However, for a given gain, obtaining a higher power leads to an increase in the propeller tension and an increase in its length. However, there is no question of reducing the gain, so as to obtain the required power without increasing the length of the propeller. This channel does not lead to a multiband traveling wave tube, of reduced length, capable of operating at high power.
L'objet de la présente invention est un tube à ondes progressives multibande dont la longueur est de l'ordre de celle du mini-TOP mais qui est capable de fonctionner à des puissances plus élevées tout en conservant un gain du même ordre.The object of the present invention is a multiband traveling wave tube whose length is of the order of that of the mini-TOP but which is capable of operating at higher powers while maintaining a gain of the same order.
A cet effet le tube à ondes progressives multibande selon l'invention comporte une ligne hyperfréquence parcourue par des électrons et dans laquelle est amplifié un signal. Cette ligne hyperfréquence comporte successivement un tronçon de ligne hyperfréquence d'entrée séparé d'une succession de tronçons de ligne hyperfréquence de sortie disjoints, chaque tronçon de sortie travaillant dans une des bandes de fonctionnement du tube. Le tronçon d'entrée est relié, à une extrémité, à des moyens d'entrée du signal à amplifier et travaille dans une bande de fréquences englobant les bandes de fréquences de fonctionnement du tube. Il est destiné à préamplifier le signal à amplifier. La succession de tronçons de sortie reçoit le signal préamplifié, chacun de ses tronçons de sortie étant destiné à l'amplifier, s'il est à une fréquence comprise dans sa bande de fréquences de travail et à le laisser passer pratiquement sans intervention, s'il est à une fréquence extérieure à sa bande de fréquences de travail, chacun des tronçons de sortie étant relié à une extrémité à des moyens de sortie du signal préamplifié qu'il a amplifié.To this end, the multiband traveling wave tube according to the invention comprises a microwave line traversed by electrons and in which a signal is amplified. This microwave line successively comprises an input microwave line section separated from a succession of disjoint output microwave line sections, each output section working in one of the operating bands of the tube. The input section is connected, at one end, to means for inputting the signal to be amplified and works in a frequency band encompassing the operating frequency bands of the tube. It is intended to preamplify the signal to be amplified. The succession of output sections receives the preamplified signal, each of its output sections being intended to amplify it, if it is at a frequency included in its working frequency band and to let it pass practically without intervention, it is at a frequency outside its working frequency band, each of the output sections being connected at one end to means for outputting the preamplified signal which it has amplified.
De préférence, les fréquences centrales des bandes de travail des tronçons de sortie décroissent avec leur éloignement du tronçon d'entrée.Preferably, the central frequencies of the working bands of the output sections decrease with their distance from the input section.
En ce qui concerne la puissance du signal amplifié par un tronçon de sortie, elle augmente plus le tronçon de sortie est éloigné du tronçon d'entrée.As for the power of the signal amplified by an output segment, it increases the more the output segment is distant from the input segment.
Les tronçons de ligne hyperfréquence sont en hélice, chaque hélice est maintenue dans un fourreau par des supports diélectriques, les différents fourreaux étant solidarisés les uns aux autres. Pour pouvoir travailler dans une très large bande, le tronçon d'entrée comporte des moyens de correction de dispersion tels que des vannes.The microwave line sections are helical, each helix is held in a sheath by dielectric supports, the different sheaths being secured to each other. To be able to work in a very wide band, the inlet section includes dispersion correction means such as valves.
On donnera de préférence à l'hélice du premier tronçon de sortie sensiblement la même longueur et/ou le même diamètre intérieur qu'à l'hélice du tronçon d'entrée.The propeller of the first outlet section will preferably be given substantially the same length and / or the same internal diameter as that of the propeller of the inlet section.
Le fil d'hélice du premier tronçon de sortie aura aussi de préférence la même section que celle du fil d'hélice du tronçon d'entrée.The helix wire of the first outlet segment will also preferably have the same cross-section as that of the helix wire of the inlet segment.
Pour conserver dans le premier tronçon de sortie, le synchronisme acquis dans le tronçon d'entrée, entre la vitesse du faisceau d'électrons et la vitesse du signal, le pas de l'hélice du premier tronçon de sortie sera de préférence plus petit que celui de l'hélice du tronçon d'entrée.To keep in the first output section, the synchronism acquired in the entry section, between the speed of the electron beam and the speed of the signal, the pitch of the helix of the first output section will preferably be smaller than that of the propeller of the inlet section.
De préférence, la longueur et/ou le pas et/ou le diamètre intérieur des hélices des tronçons de sortie augmenteront avec leur éloignement du tronçon d'entrée. Il en est de même pour la section du fil d'hélice. Pour éviter l'apparition de phénomènes d'auto-oscillation, le tronçon d'entrée est doté d'une zone d'atténuation à l'extrémité opposée à celle reliée aux moyens d'entrée du signal à amplifier.Preferably, the length and / or the pitch and / or the internal diameter of the propellers of the outlet sections will increase with their distance from the inlet section. It is the same for the section of the propeller. To avoid the appearance of self-oscillation phenomena, the input section is provided with an attenuation zone at the opposite end to that connected to the input means of the signal to be amplified.
Dans ce but, chaque tronçon de sortie est doté d'une zone d'atténuation à l'extrémité opposée à celle reliée aux moyens de sortie du signal qu'il a amplifié.For this purpose, each output section is provided with an attenuation zone at the end opposite to that connected to the output means of the signal which it has amplified.
D'autres avantages et caractéristiques de l'invention apparaîtront à la lecture de la description qui suit d'exemples de réalisation de tubes selon l'invention, description illustrée par les figures qui représentent : - la figure 1 une coupe longitudinale schématisée d'un tube à ondes progressives selon l'invention ;Other advantages and characteristics of the invention will appear on reading the following description of embodiments of tubes according to the invention, description illustrated by the figures which represent: - Figure 1 a schematic longitudinal section of a traveling wave tube according to the invention;
- la figure 2 une vue schématique éclatée d'un tube à ondes progressives à hélice serrée conforme à l'invention ;- Figure 2 an exploded schematic view of a traveling wave tube with tight propeller according to the invention;
- les figures 3a, 3b des coupes transversales de deux variantes du tronçon d'entrée ;- Figures 3a, 3b cross sections of two variants of the inlet section;
- les figures 3c, 3d respectivement la vitesse de phase normalisée et le gain en fonction de la fréquence du tronçon d'entrée de la figure 3a ;- Figures 3c, 3d respectively the normalized phase speed and the gain as a function of the frequency of the input section of Figure 3a;
- la figure 4a une coupe transversale du premier tronçon de sortie; - les figures 4b, 4c respectivement la vitesse de phase normalisée et le gain en fonction de la fréquence du premier tronçon de sortie de la figure 4a ;- Figure 4a a cross section of the first outlet section; - Figures 4b, 4c respectively the normalized phase speed and the gain as a function of the frequency of the first output section of Figure 4a;
- la figure 5a une coupe transversale du dernier tronçon de sortie;- Figure 5a a cross section of the last outlet section;
- les figures 5b, 5c respectivement la vitesse de phase normalisée et le gain en fonction de la fréquence du dernier tronçon de sortie de la figure 5a ;- Figures 5b, 5c respectively the normalized phase speed and the gain as a function of the frequency of the last output section of Figure 5a;
- la figure 6 l'allure de la puissance d'un signal injecté dans le tube de la figure 2 et parcourant la ligne hyperfréquence en fonction de sa fréquence. Sur ces figures, les échelles ne sont pas forcément respectées dans un souci de clarté.- Figure 6 the shape of the power of a signal injected into the tube of Figure 2 and traversing the microwave line as a function of its frequency. In these figures, the scales are not necessarily observed for the sake of clarity.
La figure 1 schématise un tube à ondes progressives multibande selon l'invention.Figure 1 shows schematically a multiband traveling wave tube according to the invention.
De manière conventionnelle, il comporte successivement dans une enveloppe 5, un canon 1 pour produire un faisceau 2 d'électrons, un corps 3 dans lequel se produit une interaction entre le faisceau 2 d'électrons et un signal à amplifier, un collecteur 4 pour recueillir les électrons du faisceau 2 à leur sortie du corps 3.Conventionally, it successively comprises in an envelope 5, a gun 1 to produce a beam 2 of electrons, a body 3 in which there is an interaction between the electron beam 2 and a signal to be amplified, a collector 4 to collect the electrons from the beam 2 as they exit the body 3.
Selon l'invention, le faisceau 2 d'électrons traverse entre l'entrée 6 et la sortie 7 du corps 3, une ligne hyperfréquence 8 formée de plusieurs tronçons h, h1..., hi,...hn de lignes hyperfréquences disjoints, disposés les uns à la suite des autres. Parmi ces tronçons, le premier tronçon traversé par le faisceau 2 est un tronçon h dit d'entrée, d'autres h1 , hi, hn forment une succession de tronçons dits de sortie et leur nombre n est égal au nombre de bandes de fréquences B1 , Bi, Bn dans lesquelles le tube est destiné à fonctionner, n étant un entier supérieur ou égal à deux. Chacun des tronçons de sortie h1 ,...hi, ...hn est destiné à travailler dans une des bandes de fonctionnement du tube respectivement B1..., Bi, ... Bn. Chaque bande de fréquences B1..., Bi, ... Bn est centrée sur une fréquence centrale respectivement F1 , Fi, Fn. Chaque bande de fréquences est associée à un tronçon de sortie.According to the invention, the electron beam 2 crosses between the input 6 and the output 7 of the body 3, a microwave line 8 formed of several sections h, h1 ..., hi, ... hn of disjoint microwave lines , arranged one after the other. Among these sections, the first section crossed by the beam 2 is a section h called input, others h1, hi, hn form a succession of so-called output sections and their number n is equal to the number of frequency bands B1 , Bi, Bn in which the tube is intended to operate, n being an integer greater than or equal to two. Each of the output sections h1, ... hi, ... hn is intended to work in one of the operating bands of the tube respectively B1 ..., Bi, ... Bn. Each frequency band B1 ..., Bi, ... Bn is centered on a central frequency respectively F1, Fi, Fn. Each frequency band is associated with an output segment.
Le faisceau 2 d'électrons pénètre dans chacun des tronçons h, h1 ,...hi hn par une extrémité d'entrée ee et en sort par une extrémité de sortie es. Le tronçon d'entrée h est destiné à fonctionner en tant que préamplificateur dans une très large bande B englobant toutes les bandes B1 , Bi, Bn de fonctionnement du tube. L'extrémité d'entrée ee du tronçon h d'entrée est reliée à des moyens d'entrée E d'un signal à amplifier dans le tube. Son extrémité de sortie es avoisine l'extrémité d'entrée ee du premier tronçon de sortie h1.The electron beam 2 enters each of the sections h, h1, ... hi hn via an inlet end ee and leaves it through an outlet end es. The input section h is intended to function as a preamplifier in a very wide band B encompassing all the bands B1, Bi, Bn of operation of the tube. The input end ee of the input section h is connected to input means E of a signal to be amplified in the tube. Its outlet end is around the inlet end ee of the first outlet section h1.
Les fréquences centrales F1 , Fi, Fn des bandes B1 , Bi, Bn de travail des tronçons de sortie h1 , hi, hn décroissent avec leur éloignement du tronçon d'entrée h. On a alors F1 > Fi > Fn.The central frequencies F1, Fi, Fn of the working bands B1, Bi, Bn of the output sections h1, hi, hn decrease with their distance from the input section h. We then have F1> Fi> Fn.
Chaque tronçon de sortie h1 , hi, hn de la succession est destiné à amplifier le signal préamplifié dans le tronçon d'entrée h, si le signal préamplifié est à une fréquence comprise dans sa bande de fréquences de travail B1 , Bi, Bn. Les tronçons de sortie h1 , hi, hn sont pratiquement sans action sur le signal préamplifié qui les parcourt et qui n'est pas à une fréquence comprise dans leur bande de fréquence de travail. Chacune des extrémités de sortie es des tronçons de sortie h1 , hi, hn est reliée à des moyens de sortie S1 , Si, Sn du signal préamplifié le parcourant, si ce dernier a été amplifié dans le dit tronçon de sortie h1 , hi, hn. Le signal à amplifier, injecté à l'extrémité d'entrée ee du tronçon d'entrée h, le parcourt, y est préamplifié puis pénètre dans le premier tronçon h1 de sortie. Le signal préamplifié qui parcourt le premier tronçon de sortie h1 y est amplifié, si sa fréquence est comprise dans la bande B1 , il est ensuite extrait par les moyens de sortie S1. Si la fréquence du signal préamplifié n'est pas dans la bande B1 , le signal préamplifié parcourt le premier tronçon de sortie h1 pratiquement, sans couplage avec le faisceau d'électrons 2, et à l'extrémité de sortie es du premier tronçon h1 , il pénètre dans le second tronçon h2 de sortie où il est amplifié, si sa fréquence est dans la bande B2, puis il est extrait. Si sa fréquence n'est pas dans la bande B2, il pénètre dans le troisième tronçon h3 de sortie et ainsi de suite de tronçon en tronçon jusqu'à ce qu'il soit amplifié dans le tronçon adéquat, puis extrait.Each output segment h1, hi, hn of the succession is intended to amplify the preamplified signal in the input segment h, if the preamplified signal is at a frequency included in its working frequency band B1, Bi, Bn. The output sections h1, hi, hn have practically no action on the preamplified signal which passes through them and which is not at a frequency included in their working frequency band. Each of the output ends of the output sections h1, hi, hn is connected to output means S1, Si, Sn of the preamplified signal passing through it, if the latter has been amplified in said output section h1, hi, hn . The signal to be amplified, injected at the input end ee of the input segment h, travels through it, is preamplified there and then enters the first output segment h1. The preamplified signal which traverses the first output segment h1 is amplified there, if its frequency is included in the band B1, it is then extracted by the output means S1. If the frequency of the preamplified signal is not in the band B1, the preamplified signal traverses the first output segment h1 practically, without coupling with the electron beam 2, and at the output end es of the first segment h1, it enters the second output segment h2 where it is amplified, if its frequency is in the band B2, then it is extracted. If its frequency is not in band B2, it enters the third output section h3 and so on from section to section until it is amplified in the appropriate section, then extracted.
On suppose qu'un signal de fréquence F se propage dans le tronçon de sortie hi (i entier compris entre 1 et n - 2), s'il n'y est pas amplifié cela signifie que la fréquence F n'est pas incluse dans la bande Bi. Le signal de fréquence F n'est pas extrait à l'extrémité de sortie du tronçon hi de sortie et il pénètre alors dans le tronçon de sortie suivant hi + 1. Si sa fréquence F est dans la bande de fréquences Bi+1 associée au tronçon de sortie hi + 1 , il est amplifié puis extrait à l'extrémité es dudit tronçon hi + 1. Si sa fréquence F est hors de la bande Bi + 1 , il pénètre dans le tronçon suivant hi + 2 et ainsi de suite.It is assumed that a signal of frequency F propagates in the output section hi (i integer between 1 and n - 2), if it is not amplified it means that the frequency F is not included in the Bi band. The frequency signal F is not extracted at the output end of the output segment hi and it then enters the next output segment hi + 1. If its frequency F is in the frequency band Bi + 1 associated with output section hi + 1, it is amplified and then extracted at the end es of said section hi + 1. If its frequency F is outside the band Bi + 1, it enters the next section hi + 2 and so on.
On va voir maintenant plus en détail un exemple de mode de réalisation d'un tube selon l'invention. On suppose qu'il s'agit d'un tube à ondes progressives bi-bande. La figure 2 montre un tel tube vu de l'extérieur mais dont l'enveloppe 5 est partiellement ouverte de manière à laisser apparaître les différents tronçons de ligne hyperfréquence h, h1 , h2 qui sont en hélice. Les autres éléments intérieurs à l'enveloppe tels que le canon, le focalisateur, le collecteur ne sont pas représentés dans un souci de clarté. Les hélices 20, 21 , 22 insérées chacune dans un fourreau 11 , 11.1 , 11.2 conducteur sont maintenues dans le fourreau 11 , 11.1 , 11.2 à l'aide de supports 12, 12.1 , 12.2 isolants. On a prévu dans l'exemple trois supports 12, 12.1 , 12.2 isolants par hélice (mais seul un est visible sur la figure 2) et ces derniers sont sensiblement de la longueur de l'hélice 20, 21 , 22 qu'ils maintiennent. Les supports peuvent être de manière conventionnelle, en nitrure de bore, alumine ou oxyde de béryllium par exemple. Les hélices 20, 21 , 22 sont sans contact les unes avec les autres. Les différents fourreaux 11 , 11.1 , 11.2 sont solidaires les uns des autres. Cette solidarisation est étanche.We will now see in more detail an exemplary embodiment of a tube according to the invention. It is assumed to be a dual band traveling wave tube. FIG. 2 shows such a tube seen from the outside but whose casing 5 is partially open so as to reveal the various sections of microwave line h, h1, h2 which are in a helix. The other elements inside the envelope such as the barrel, the focusing device, the collector are not shown for the sake of clarity. The propellers 20, 21, 22 each inserted into a conductive sheath 11, 11.1, 11.2 are held in the sheath 11, 11.1, 11.2 using insulating supports 12, 12.1, 12.2. In the example, three insulating supports 12, 12.1, 12.2 are provided per helix (but only one is visible in FIG. 2) and the latter are substantially of the length of the helix 20, 21, 22 which they maintain. The supports can be conventionally made of boron nitride, alumina or beryllium oxide for example. The propellers 20, 21, 22 are in contact with each other. The different sleeves 11, 11.1, 11.2 are integral with each other. This connection is waterproof.
L'extrémité d'entrée ee du tronçon h d'entrée est reliée à des moyens d'entrée E d'un signal à amplifier représentés sous la forme d'une ligne coaxiale.The input end ee of the input section h is connected to input means E of a signal to be amplified represented in the form of a coaxial line.
Les deux tronçons de sortie h1 , h2 travaillent respectivement dans la bande B1 , B2, de fréquence centrale respective F1 , F2. La fréquence F1 est supérieure à la fréquence F2. L'extrémité de sortie es du tronçon h1 est reliée à des moyens de sortie S1 du signal préamplifié s'il a été amplifié par ledit tronçon h1. Les moyens de sortie S1 sont représentés par un guide d'onde ce qui est classique à haute fréquence. L'extrémité de sortie es du tronçon h2 est reliée à des moyens de sortie S2 du signal qui a été amplifié par le tronçon h2. Dans l'exemple il s'agit d'une ligne coaxiale. Il est bien entendu que chacun des moyens d'entrée et de sortie pourrait être de nature différente. Le tronçon h est destiné à travailler dans une très large bande B englobant les deux bandes B1 et B2. On va voir de manière plus précise les caractéristiques de chacun des tronçons de ligne h, h1 , h2.The two output sections h1, h2 work respectively in the band B1, B2, of respective central frequency F1, F2. The frequency F1 is greater than the frequency F2. The output end es of the section h1 is connected to output means S1 of the preamplified signal if it has been amplified by said section h1. The output means S1 are represented by a waveguide which is conventional at high frequency. The output end es of the section h2 is connected to output means S2 of the signal which has been amplified by the section h2. In the example it is a coaxial line. It is understood that each of the entry and exit means could be of a different nature. The section h is intended to work in a very wide band B encompassing the two bands B1 and B2. We will see more precisely the characteristics of each of the line sections h, h1, h2.
Afin que le tronçon d'entrée h puisse travailler dans la très large bande B, tout en imposant que la vitesse de phase normalisée du signal devant être préamplifié reste sensiblement constante quelle que soit la fréquence, le tronçon d'entrée h comporte des moyens de correction de dispersion 13 tels que des vannes par exemple. Sur la figure 3a, les vannes 13 sont distinctes des supports 12, ce sont des conducteurs s'étendant longitudinalement le long de l'hélice 20 et qui se projettent depuis le fourreau 11 vers l'hélice 20. Ces vannes 13 sont séparées de l'hélice 20 par un espace 14. Elles sont placées entre les supports 12. Un autre type de vannes peut être employé comme l'illustre la figure 3b. Ces vannes intégrées aux supports diélectriques sont décrites dans le brevet européen EP-B- 0 401 065. L'hélice est maintenue par les supports diélectriques 120 qui sont à leur tour supportés par des éléments conducteurs 130 en saillie par rapport à la paroi intérieure du fourreau 11 vers l'hélice 20. Cette configuration a pour avantage de moins obstruer l'intérieur du fourreau ce qui permet de réduire le temps nécessaire au pompage et d'améliorer qualitativement le vide.So that the input segment h can work in the very wide band B, while requiring that the normalized phase speed of the signal to be preamplified remains substantially constant whatever the frequency, the input segment h comprises means of dispersion correction 13 such as valves for example. In FIG. 3a, the valves 13 are distinct from the supports 12, these are conductors extending longitudinally along the propeller 20 and which project from the sheath 11 towards the propeller 20. These valves 13 are separated from the propeller 20 by a space 14. They are placed between the supports 12. Another type of valve can be used as shown in Figure 3b. These valves integrated into the dielectric supports are described in European patent EP-B- 0 401 065. The propeller is held by the dielectric supports 120 which are in turn supported by conductive elements 130 projecting from the inner wall of the sheath 11 towards the propeller 20. This configuration has the advantage of less obstructing the interior of the sheath, which makes it possible to reduce the time required for pumping and to improve the vacuum qualitatively.
On peut espérer obtenir un rapport compris entre 2 et 4 entre la fréquence centrale F2 la plus basse et la fréquence centrale la plus haute F1.We can hope to obtain a ratio between 2 and 4 between the lowest central frequency F2 and the highest central frequency F1.
Les figures 3a et 3b montrent des coupes transversales de tronçon d'entrée h. Le diamètre intérieur d de l'hélice 20 est relativement petit pour que le tronçon h puisse travailler en préamplificateur dans la bande B englobant toutes les bandes de fonctionnement du tube. Ce diamètre dépend de la bande des fréquences à amplifier.Figures 3a and 3b show cross sections of inlet section h. The internal diameter d of the propeller 20 is relatively small so that the section h can work as a preamplifier in the band B encompassing all the operating bands of the tube. This diameter depends on the frequency band to be amplified.
La figure 3c est un diagramme de la vitesse de phase normalisée c/vφ du signal se propageant dans le tronçon d'entrée h en fonction de la fréquence F. On suppose dans l'exemple décrit que le tube est destiné à fonctionner dans deux bandes B1 , B2 centrées respectivement autour de la fréquence F0 et de la fréquence 3F0. La vitesse de phase c/vφ normalisée est le rapport de la vitesse de phase vφ sur la vitesse de la lumière c. La courbe en trait plein est obtenue dans le tronçon d'entrée h avec vannes 13 distinctes des supports 12 et la courbe en pointillés est celle que l'on obtiendrait en l'absence des vannes 13.FIG. 3c is a diagram of the normalized phase speed c / vφ of the signal propagating in the input section h as a function of the frequency F. It is assumed in the example described that the tube is intended to operate in two bands B1, B2 centered respectively around the frequency F0 and the frequency 3F0. The normalized phase speed c / vφ is the ratio of the phase speed vφ to the speed of light c. The solid line curve is obtained in the inlet section h with valves 13 distinct from the supports 12 and the dotted curve is that which would be obtained in the absence of the valves 13.
La figure 3d est le gain G du tronçon d'entrée h en fonction de la fréquence F. Le gain maximum Gmax est obtenu dans la partie médiane de la courbe, c'est-à-dire pour une fréquence médiane, les fréquences F0 et 3F0 sont situées de part et d'autre de la fréquence médiane. Dans les bandes B1 , B2 de fonctionnement, le gain est inférieur d'environ 4 à 5 dB par rapport au gain maximum.FIG. 3d is the gain G of the input section h as a function of the frequency F. The maximum gain Gmax is obtained in the median part of the curve, that is to say for a median frequency, the frequencies F0 and 3F0 are located on either side of the median frequency. In the operating bands B1, B2, the gain is approximately 4 to 5 dB lower than the maximum gain.
Le premier tronçon de sortie h1 est celui qui travaille en amplification à la fréquence la plus élevée, ici 3F0. Sa bande B1 de fonctionnement est plus étroite que la bande B et le tronçon h1 ne nécessite pas de moyens de correction de dispersion. La figure 4a montre en coupe transversale le premier tronçon h1 de sortie avec les supports diélectriques 12.1. Son hélice 21 peut être réalisée pour simplifier avec le même fil que l'hélice 20 du tronçon d'entrée h si la puissance désirée en sortie es du premier tronçon de sortie n'est pas trop élevée. Elle possédera sensiblement le même diamètre intérieur d1 que celui d de l'hélice 20 du tronçon d'entrée h puisque ce premier tronçon h1 de sortie est associé à la bande B1 dont la fréquence centrale 3F0 est la plus élevée.The first output section h1 is the one that works in amplification at the highest frequency, here 3F0. Its operating band B1 is narrower than band B and the section h1 does not require dispersion correction means. FIG. 4a shows in cross section the first output section h1 with the dielectric supports 12.1. Its propeller 21 can be made to simplify with the same wire as the propeller 20 of the inlet section h if the desired power at the outlet es of the first outlet section is not too high. It will have substantially the same internal diameter d1 as that of the propeller 20 of the inlet section h since this first outlet section h1 is associated with the band B1 whose central frequency 3F0 is the highest.
Par contre son pas p1 pourra être plus petit que celui p de l'hélice 20 du tronçon h d'entrée pour conserver le synchronisme entre la vitesse du faisceau d'électrons et la vitesse du signal qui la parcourt, synchronisme acquis dans le tronçon h d'entrée.On the other hand, its pitch p1 may be smaller than that p of the propeller 20 of the input section h to maintain the synchronism between the speed of the electron beam and the speed of the signal which travels through it, synchronism acquired in the section h entry.
La longueur 11 de l'hélice 21 est liée au gain nécessaire pour obtenir la puissance désirée à la fréquence 3F0. Il est souhaitable que le gain du premier tronçon h1 de sortie soit supérieur à celui du tronçon h d'entrée. Toutefois, la longueur 11 de l'hélice du premier tronçon de sortie h1 peut être du même ordre que celle de l'hélice 20 du tronçon d'entrée h, car le gain par unité de longueur d'une ligne en hélice sans moyens de correction de dispersion est plus grand que celui d'une ligne en hélice avec moyens de correction de dispersion.The length 11 of the propeller 21 is linked to the gain necessary to obtain the desired power at the frequency 3F0. It is desirable that the gain of the first output segment h1 be greater than that of the input segment h1. However, the length 11 of the propeller of the first outlet section h1 can be of the same order as that of the propeller 20 of the inlet section h, since the gain per unit length of a helical line without means of dispersion correction is greater than that of a helical line with dispersion correction means.
On peut espérer atteindre pour une fréquence de plusieurs dizaines de gigahertz une puissance de sortie de l'ordre de la centaine de watt.We can hope to reach, for a frequency of several tens of gigahertz, an output power of the order of a hundred watt.
La figure 4b montre l'allure de la vitesse de phase normalisée en fonction de la fréquence pour ce premier tronçon h1 de sortie tandis que la figure 4c montre l'allure du gain en fonction de la fréquence. Le gain est maximum pour la fréquence centrale 3F0.FIG. 4b shows the shape of the normalized phase speed as a function of the frequency for this first output segment h1 while FIG. 4c shows the shape of the gain as a function of the frequency. The gain is maximum for the center frequency 3F0.
La figure 5a montre une coupe transversale du tronçon h2 de sortie suivant qui ici est le dernier. Il est associé à la bande B2 de fréquence centrale F0 la plus basse.Figure 5a shows a cross section of the next outlet section h2 which here is the last. It is associated with the lowest central frequency band B2 F0.
Ce second tronçon de sortie h2 ne nécessite pas non plus de moyens de correction de dispersion puisque la bande B2 est plus étroite que la bande B. Il en serait de même pour tous les autres tronçons de sortie.This second outlet section h2 also does not require dispersion correction means since the strip B2 is narrower than the strip B. It would be the same for all the other outlet sections.
Le diamètre intérieur d2 de son hélice 22 est plus grand que celui de l'hélice 21 du tronçon h1 de sortie qui le précède. Le diamètre intérieur de l'hélice varie de matière sensiblement inversement proportionnelle à la fréquence de fonctionnement pour que le paramètre d'amplification reste constant. Le rapport des deux diamètres d1 , d2 est environ le même que celui des fréquences 3F0, F0 centrales correspondantes. Plus généralement le diamètre intérieur des hélices des tronçons de sortie h1 , h2 augmente avec leur éloignement du tronçon d'entrée h. Avec une telle configuration, le diamètre du faisceau d'électrons augmente plus on se rapproche du collecteur. La focalisation du faisceau se fait donc en conséquence de manière classique pour un homme du métier. Les supports 12.2 qui maintiennent l'hélice 22 sont adaptés au diamètre de l'hélice et à celui du tronçon 11.2 de fourreau. Les différents tronçons 11 , 11.1 , 11.2 de fourreau peuvent ne pas avoir le même diamètre.The internal diameter d2 of its propeller 22 is larger than that of the propeller 21 of the outlet section h1 which precedes it. The inner diameter of the propeller varies in material substantially inversely proportional to the operating frequency so that the amplification parameter remains constant. The ratio of the two diameters d1, d2 is approximately the same as that of the corresponding central frequencies 3F0, F0. More generally, the internal diameter of the propellers of the outlet sections h1, h2 increases with their distance from the inlet section h. With such a configuration, the diameter of the electron beam increases the closer one gets to the collector. The focusing of the beam is therefore done conventionally for a person skilled in the art. The supports 12.2 which hold the propeller 22 are adapted to the diameter of the propeller and to that of the section 11.2 of the sheath. The different sections 11, 11.1, 11.2 of sheath may not have the same diameter.
Le pas p2 de l'hélice 22 du second tronçon h2 de sortie est supérieur à celui p1 du tronçon h1 de sortie qui le précède, toujours dans l'optique de conserver le synchronisme entre la vitesse du faisceau d'électrons et la vitesse du signal qui parcourt l'hélice 22. Plus généralement le pas des hélices des tronçons de sortie augmente avec leur éloignement du tronçon d'entrée.The pitch p2 of the propeller 22 of the second output segment h2 is greater than that p1 of the output segment h1 which precedes it, still with the aim of maintaining synchronism between the speed of the electron beam and the speed of the signal which runs through the propeller 22. More generally, the pitch of the propellers of the outlet sections increases with their distance from the inlet section.
On suppose que le signal produit par le tronçon de sortie h2 a une puissance supérieure à celle du signal produit par le tronçon h1 de sortie qui le précède, ce qui conduit à donner au fil de l'hélice 22 une section plus grande que celle du fil de l'hélice 21. On peut atteindre en sortie du tronçon h2 de sortie des puissances trois à quatre fois supérieures à celles obtenues en sortie du tronçon h1 de sortie. En généralisant, la section du fil des hélices des tronçons de sortie augmentera avec leur éloignement du tronçon d'entrée.It is assumed that the signal produced by the output segment h2 has a power greater than that of the signal produced by the output segment h1 which precedes it, which leads to giving the thread of the propeller 22 a larger section than that of the propeller wire 21. It is possible to reach, at the output of the output segment h2, powers three to four times greater than those obtained at the output of the output segment h1. By generalizing, the section of the wire of the propellers of the output sections will increase with their distance from the input section.
La longueur 12 de l'hélice 22 est liée au gain nécessaire pour obtenir la puissance désirée à la fréquence F0. On donnera au tronçon h2 une longueur 12 supérieure à celle 11 du tronçon h1 de sortie qui le précède car la fréquence à laquelle il travaille est plus basse. Plus généralement dans la succession, la longueur des l'hélices des tronçons de sortie augmente avec leur éloignement du tronçon d'entrée.The length 12 of the propeller 22 is related to the gain necessary to obtain the desired power at the frequency F0. The section h2 will be given a length 12 greater than that 11 of the outlet section h1 which precedes it because the frequency at which it works is lower. More generally in succession, the length of the propellers of the outlet sections increases with their distance from the inlet section.
Avec une longueur 12 supérieure de quelques centimètres par rapport à la longueur I, on peut espérer atteindre, pour une fréquence de l'ordre de la dizaine de gigahertz, une puissance de sortie de plusieurs centaines de watts.With a length 12 a few centimeters higher than the length I, we can hope to reach, for a frequency of around ten gigahertz, an output power of several hundred watts.
La figure 5b montre d'allure de la vitesse de phase normalisée en fonction de la fréquence pour ce second tronçon de sortie h2 tandis que la figure 5c montre l'allure de son gain en fonction de la fréquence. Le gain est maximum pour la fréquence centrale F0.FIG. 5b shows the shape of the normalized phase speed as a function of the frequency for this second output section h2 while FIG. 5c shows the shape of its gain as a function of the frequency. The gain is maximum for the central frequency F0.
De manière conventionnelle, pour éviter des phénomènes d'auto- oscillation dans le tube, on prévoit au niveau des tronçons h, h1 , h2 de ligne hyperfréquence une zone d'atténuation 30, 31 , 32. Plus précisément, ces zones d'atténuation recouvrent les supports 12, 12.1 , 12.2 des hélices 20, 21 , 22. Ces zones d'atténuation peuvent être réalisées par un dépôt de carbone par exemple. Ces zones d'atténuation sont situées respectivement la première 30 à proximité de l'extrémité de sortie es du tronçon d'entrée h et les autres 31 , 32 à proximité de l'extrémité d'entrée ee des tronçons de sortie respectifs h1 , h2. La zone d'atténuation 31 du premier tronçon h1 de sortie a environ la même longueur que celle du tronçon d'entrée h. En revanche la zone d'atténuation 32 d'un autre tronçon de sortie h2 est plus longue que celle 31 du tronçon de sortie h1 qui le précède.Conventionally, to avoid self-oscillation phenomena in the tube, an attenuation zone 30, 31, 32 is provided at the sections h, h1, h2 of the microwave line. More precisely, these attenuation zones cover the supports 12, 12.1, 12.2 of the propellers 20, 21, 22. These attenuation zones can be produced by a carbon deposit for example. These attenuation zones are located respectively the first 30 near the outlet end es of the inlet section h and the other 31, 32 near the inlet end ee of the respective outlet sections h1, h2 . The attenuation zone 31 of the first outlet section h1 has approximately the same length as that of the inlet section h. On the other hand, the attenuation zone 32 of another outlet section h2 is longer than that 31 of the outlet section h1 which precedes it.
La figure 6 montre l'allure de la puissance P (exprimée en dBm) d'un signal injecté avec une amplitude Pe dans le tube de la figure 2 et qui parcourt la ligne hyperfréquence jusqu'à son extraction, soit au niveau des moyens de sortie S1 , soit au niveau des moyens de sortie S2.FIG. 6 shows the shape of the power P (expressed in dBm) of a signal injected with an amplitude Pe into the tube of FIG. 2 and which traverses the microwave line until it is extracted, ie at the level of the means of output S1, ie at the output means S2.
Le signal extrait au niveau des moyens de sortie S1 a une puissance d'amplitude P1 et est à la fréquence 3F0. Le signal extrait au niveau des moyens de sortie S2 a une puissance P2 et est à une fréquence F0. L'amplitude P2 est environ trois fois plus grande que l'amplitude P1.The signal extracted at the output means S1 has an amplitude power P1 and is at the frequency 3F0. The signal extracted at the output means S2 has a power P2 and is at a frequency F0. The amplitude P2 is approximately three times greater than the amplitude P1.
On remarque que les puissances chutent fortement au niveau des zones d'atténuation 30, 31 , 32 qui sont symbolisées par des triangles. Dans chaque tronçon de sortie, le signal qui y est amplifié a son amplitude qui croit fortement dès qu'il se propage au delà de la zone d'atténuation 31 , 32 correspondante. It is noted that the powers drop sharply at the level of the attenuation zones 30, 31, 32 which are symbolized by triangles. In each output section, the signal which is amplified therein has its amplitude which increases strongly as soon as it propagates beyond the corresponding attenuation zone 31, 32.

Claims

REVENDICATIONS
1. Tube à ondes progressives apte à fonctionner en amplificateur dans plusieurs bandes de fréquences (B1 , Bi, Bn), comportant une ligne hyperfréquence (8) parcourue par des électrons et dans laquelle est amplifié un signal, caractérisé en ce que la ligne hyperfréquence (8) comporte successivement un tronçon de ligne hyperfréquence d'entrée (h) séparé d'une succession de tronçons de ligne hyperfréquence de sortie (h1 , hi, hn) disjoints, chaque tronçon de sortie (h1 , hi, hn) travaillant dans une des bandes de fréquences (B1 , Bi, Bn) de fonctionnement du tube,1. A traveling wave tube capable of operating as an amplifier in several frequency bands (B1, Bi, Bn), comprising a microwave line (8) traversed by electrons and in which a signal is amplified, characterized in that the microwave line (8) successively comprises a segment of input microwave line (h) separated from a succession of segments of microwave output line (h1, hi, hn) which are disjoint, each output segment (h1, hi, hn) working in one of the frequency bands (B1, Bi, Bn) operating the tube,
- le tronçon d'entrée (h), relié à une extrémité (ee) à des moyens d'entrée (E) du signal à amplifier, travaillant dans une bande de fréquences (B) englobant les bandes de fréquences (B1 , Bi, Bn) de fonctionnement du tube, étant destiné à préamplifier le signal à amplifier,the input section (h), connected at one end (ee) to input means (E) of the signal to be amplified, working in a frequency band (B) encompassing the frequency bands (B1, Bi, Bn) operating the tube, being intended to preamplify the signal to be amplified,
- la succession de tronçons de sortie (h1 , hi, hn) recevant le signal préamplifié, chacun des tronçons de sortie étant destiné à l'amplifier s'il est à une fréquence comprise dans sa bande de fréquences de travail, et à le laisser passer pratiquement sans intervention, s'il est à une fréquence extérieure à sa bande de fréquences de travail, chacun des tronçons de sortie (h1 , hi, hn) étant relié à une extrémité de sortie (es) à des moyens de sortie (S, Si, Sn) du signal préamplifié qu'il a amplifié.- the succession of output sections (h1, hi, hn) receiving the preamplified signal, each of the output sections being intended to amplify it if it is at a frequency included in its working frequency band, and to leave it pass practically without intervention, if it is at a frequency outside its working frequency band, each of the output sections (h1, hi, hn) being connected at one output end (es) to output means (S , Si, Sn) of the preamplified signal which it amplified.
2. Tube à ondes progressives selon la revendication 1 , caractérisé en ce que les fréquences centrales (F1 , Fi, Fn) des bandes de fréquences de travail (B1 , Bi, Bn) des tronçons de sortie (h1 , hi, hn) décroissent avec leur éloignement du tronçon d'entrée (h).2. traveling wave tube according to claim 1, characterized in that the central frequencies (F1, Fi, Fn) of the working frequency bands (B1, Bi, Bn) of the output sections (h1, hi, hn) decrease with their distance from the entry section (h).
3. Tube à ondes progressives selon l'une des revendications 1 ou 2, caractérisé en ce que la puissance du signal amplifié par un tronçon de sortie (hi) augmente plus le tronçon de sortie (hi) est éloigné du tronçon d'entrée (h).3. traveling wave tube according to one of claims 1 or 2, characterized in that the power of the signal amplified by an output segment (hi) increases the further the output segment (hi) is distant from the input segment ( h).
4. Tube à ondes progressives selon l'une des revendications 1 à 3, caractérisé en ce que les tronçons d'entrée (h) et de sortie (h1 , h2) sont en hélice, chaque hélice (20, 21 , 22) étant maintenue dans un fourreau (11 , 4. traveling wave tube according to one of claims 1 to 3, characterized in that the inlet (h) and outlet (h1, h2) sections are in a helix, each helix (20, 21, 22) being held in a sheath (11,
11.1 , 11.2) conducteur par des supports diélectriques (12, 12.1 , 12.2), les tronçons (11 , 11.1 , 11.2) étant solidaires les uns des autres.11.1, 11.2) conductive by dielectric supports (12, 12.1, 12.2), the sections (11, 11.1, 11.2) being integral with each other.
5. Tube à ondes progressives selon la revendication 4, caractérisé en ce que le tronçon d'entrée (h) comporte des moyens (13) de correction de dispersion.5. traveling wave tube according to claim 4, characterized in that the inlet section (h) comprises means (13) for correcting dispersion.
6. Tube à ondes progressives selon la revendication 5, caractérisé en ce que les moyens (13) de correction de dispersion sont des vannes.6. traveling wave tube according to claim 5, characterized in that the means (13) of dispersion correction are valves.
7. Tube à ondes progressives selon l'une des revendications 4 à 5, caractérisé en ce que la longueur (11 ) et/ou le diamètre (d1 ) intérieur de l'hélice (21 ) du premier tronçon de sortie (h1 ) sont sensiblement les mêmes que ceux de l'hélice (20) du tronçon d'entrée.7. traveling wave tube according to one of claims 4 to 5, characterized in that the length (11) and / or the diameter (d1) inside of the propeller (21) of the first outlet section (h1) are substantially the same as those of the propeller (20) of the inlet section.
8. Tube à ondes progressives selon l'une des revendications 4 à 7, caractérisé en ce que le pas (p1 ) de l'hélice du premier tronçon de sortie (h1 ) est plus petit que le pas (p) de l'hélice du tronçon d'entrée (h).8. traveling wave tube according to one of claims 4 to 7, characterized in that the pitch (p1) of the propeller of the first outlet section (h1) is smaller than the pitch (p) of the propeller of the entry section (h).
9. Tube à ondes progressives selon l'une des revendications 4 à9. traveling wave tube according to one of claims 4 to
8, caractérisé en ce que la section du fil d'hélice du premier tronçon de sortie (h1 ) est sensiblement la même que celle du fil d'hélice du tronçon d'entrée (h).8, characterized in that the section of the propeller wire of the first outlet section (h1) is substantially the same as that of the propeller wire of the inlet section (h).
10. Tube à ondes progressives selon l'une des revendications 4 à10. traveling wave tube according to one of claims 4 to
9, caractérisé en ce que la longueur et/ou le pas des hélices (22) des tronçons de sortie (h1 , h2) augmentent avec leur éloignement du tronçon d'entrée (h).9, characterized in that the length and / or the pitch of the propellers (22) of the outlet sections (h1, h2) increase with their distance from the inlet section (h).
11. Tube à ondes progressives selon l'une des revendications 4 à11. traveling wave tube according to one of claims 4 to
10, caractérisé en ce que le diamètre intérieur des hélices des tronçons de sortie (h1 , h2) augmente avec leur éloignement du tronçon d'entrée (h). 10, characterized in that the internal diameter of the propellers of the outlet sections (h1, h2) increases with their distance from the inlet section (h).
12. Tube à ondes progressives selon l'une des revendications 4 à12. traveling wave tube according to one of claims 4 to
11 , caractérisé en ce que la section du fil d'hélice des tronçons de sortie (h1 , h2) augmente avec leur éloignement du tronçon d'entrée (h).11, characterized in that the section of the helix wire of the outlet sections (h1, h2) increases with their distance from the inlet section (h).
13. Tube à ondes progressives selon l'une des revendications 1 à13. traveling wave tube according to one of claims 1 to
12, caractérisé en ce que le tronçon d'entrée (h) est doté d'une zone d'atténuation (30) à l'extrémité opposée à celle reliée aux moyens d'entrée (E) du signal à amplifier.12, characterized in that the input section (h) is provided with an attenuation zone (30) at the end opposite to that connected to the input means (E) of the signal to be amplified.
14. Tube à ondes progressives selon l'une des revendications 1 à14. traveling wave tube according to one of claims 1 to
13, caractérisé en ce chaque tronçon de sortie (h1 , h2) est doté d'une zone d'atténuation (31 , 32) à l'extrémité opposée à celle reliée aux moyens de sortie (S1 , S2) du signal qu'il a amplifié. 13, characterized in that each output section (h1, h2) is provided with an attenuation zone (31, 32) at the end opposite to that connected to the output means (S1, S2) of the signal it has amplified.
EP99959496A 1998-12-23 1999-12-17 Multiband travelling wave tube of reduced length capable of high power functioning Expired - Lifetime EP1145268B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9816358 1998-12-23
FR9816358A FR2787918B1 (en) 1998-12-23 1998-12-23 MULTIBAND PROGRESSIVE WAVE TUBE OF REDUCED LENGTH CAPABLE OF OPERATING AT HIGH POWER
PCT/FR1999/003190 WO2000039832A2 (en) 1998-12-23 1999-12-17 Multiband travelling wave tube of reduced length capable of high power functioning

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EP1145268A2 true EP1145268A2 (en) 2001-10-17
EP1145268B1 EP1145268B1 (en) 2005-05-11

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EP (1) EP1145268B1 (en)
JP (1) JP2002533901A (en)
DE (1) DE69925310D1 (en)
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JP2006134751A (en) * 2004-11-08 2006-05-25 Nec Microwave Inc Electron tube
JP2013030377A (en) * 2011-07-29 2013-02-07 Mitsubishi Electric Corp Helix type traveling-wave tube and helix type traveling-wave tube manufacturing method
CN103247503B (en) * 2013-04-17 2016-03-09 中国电子科技集团公司第十二研究所 A kind of Terahertz cascade traveling-wave tube frequency multiplier structure and manufacture method

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FR2787918A1 (en) 2000-06-30
WO2000039832A2 (en) 2000-07-06
EP1145268B1 (en) 2005-05-11
DE69925310D1 (en) 2005-06-16
WO2000039832A3 (en) 2000-10-26
FR2787918B1 (en) 2001-03-16
US6483243B1 (en) 2002-11-19
JP2002533901A (en) 2002-10-08

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