US2849643A - Double beam electron discharge tube - Google Patents

Description

Aug. 26, 1958- G. MOURIER DOUBLE BEAM ELECTRON nxscumcz: TUBE Filed Jan. i1, 195:;

5 She ets-Shet 1 1 958 G. MOURIER 2,849,643

DOUBLE BEAM ELECTRON nxscmcs: TUBE Filed Jan. 11, 1956 5 Sheets-Sheet 2 Aug. 26,- 1958 G MOURIER DOUBLE BEAM ELECTRON DISCHARGE TUBE Filed Jan. 11,1956

5 Sheets-Sheet 3 Aug 26, 1958 Filed Jan. 11, 1956 G. MOURIER 2,849,643

DOUBLE BEAM ELECTRON DISCHARGE TUBE 5 Sheets-Sheet 5 United States Patent DOUBLE BEAM ELECTRON DISCHARGE TUBE Georges Mourier, Paris, France, assignor to Coinpagnie Generals dc Telegraphie Sans Fil, a corporation of France The present invention relates to traveling wave and standing Wave electronic tubes, with bi-dimensional or bidirectional delay structures which have a geometrlcally periodicity along two perpendicular or, more generally,

intersecting directions.

It is an object of the present invention to provide'a tube 1-, of this type in which two beams, or group of beams, are

projected along two mutually intersecting directions for respective interaction with wave components propagatmg along two dimensions of the delay structure. Energy propagates in the delay structure either in traveling or in standing waves. Generally, the propagation takes place in traveling waves along at least one of the two directions considered.

The invention provides either oscillator or amplifier tubes.

The invention will be better understood from the ensuing description taken with reference to the appended drawing, wherein:

Fig. 1 is an explanatory diagram;

Fig. 2 shows diagrammatically the electrode arrangement of a tube according to the invention;

Fig. 3 is an axial cross-section of an amplifying tube according to the invention;

Fig. 4 shows the strapping diagram of the tube of Fig. 3;

Figs. 5, 6 and 7 show an oscillator tube according to the invention, in vertical longitudinal, vertical transversal and horizontal longitudinal sections, respectively;

Figs. 8 and 9 show another embodiment of the oscillator tube according to the invention, in axial and transversal sections, respectively, Fig. 9 alsoreferring to tube of Fig. 3;

Fig. 10 is the strapping diagram of the tube of Fig; 8.

The electrode arrangement of a tube according to the invention is diagrammatically shown in Fig. 2. It is as sumed that an ultra high frequency energy of a given frequency propagates in the delay structure 1. As'the case 1 may be, this energy is either fed to this structure for amplification or is generated in the same, as in the case of an Each channel is built up by a series of adjacent cells, 1

which are also coupled to each other and are diagrammatically shown in the Fig. 2 as squares C.

A first cathode 2 extending in the direction 0y is positioned for emitting a first laminary electron beam 3, or a plurality of parallel beams, in the direction Ox. This beam, after having followed a path parallel to the delay in the directions Ox and Oy. This net 'E the electrons of beam 6.

structure 1, is collected by a collector 4. A second cath ode 5, extending in the direction Ox, emits a second" laminary beam 6 in the direction Oy. An output horn 7 is'coupled to the delay structure 1 along itsedges parallel to cathode 5 and remote therefrom. As shown, this" horn comprises a well 8 extending in the direction 0y, and a wall 9 substantially parallel to the arrows10, showing the assumed general propagation direction of' energy in structure 1. Wall 9 serves as a collector for Horn 7 is connected to an out put'wave guide 11. The inclination of wall 9 is such 'as to match the horn to the structure 1. This inclination" is preferably selected, so that the matching occurs" substantially in the intermediate portion of the desired fre- 15 quency band of the tube.

Delay structure 1, horn 7 and collector 4 are' brought to a common positive potential by a source 30. Catho'des 2 and 5 are brought, by sources 30 and 32 respectively, to negative potentials with respect to this common potential. These potentials, which may be adjusted or modulated, determine the respective velocities of the beams 3 and 6.

The wave, when propagating in the structure in any direction, undergoes, in each cell C, a phase shift (p, the respective components of which, in the directions Ox and- Oy are ex and y. In the diagram of Fig. 1, tax has been plotted on the abscissae and guy on the ordinates. By making a series of measurements for a given frequency range, a set of curves P, such as that shown by way of ex ample, in Fig. 1, may be obtained for any given delay structure 1. Each curve F corresponds to a given fre quency and may be termed an isofrequcncy curve. The co-ordinates of each point of each of the curves F repre sent the respective phase shifts, along Ox and Oy, which a wave, having the frequency corresponding to the curve onrwhich is located the point under consideration, undergoes in each cell C of the delay structure 1. It will benoted that [the same frequency may correspond to difierent phase shifts (px, or gay, i. e. for a given velocity of beam- 3,or 6, a great number of frequencies may be obtained- In other words, if, in a tube having a delay structure '1, an electron beam -is projected-in the direction'Ox, this beam may' be caused to interact, either for amplification or oscillation purposes, with anyone of a great number of waves of various frequencies. If x has-the-value OB, the beam 3 may interact with all the waves,-the fre quencies of which correspond to the isofrequency =lines-= crossed by the straight line BBIZL' In the case of the oscillator, this is, obviously, a cause of instability :and indetermination of the oscillationfrequency. Y

Of course, it isto be understood that theabove expla nation is only purported to give a broad understanding-of the physical phenomenon concerned and that the applicant is not to any extent bound by,-or'-limited, tothis' explanation.

According to the invention,- two' electron beams normal to each other or, more broadly, intersecting each-otheig-z are propagated for interaction with'the energy propagating in the delay structure of the Fig.2. Referring to the diagram of Fig.1, it may be seen that only-a wavehaving a given frequency is able to interact with beams 3 and 6" simultaneously. In Fig. 1, this frequency is determined by the point of intersectionD of line BBn-and line CCh parallel to the axis. OB and 0C are respectively equal to sex and aywhich correspond gation velocities of the beams 3 modifying-the velocity of one or the'other'beam; 30rd, or of'both at the same time,thus' causing' -point'D to ber' shifted in the plane of the diagram.

According to -the"knowii techniqueof the"traveliiig"" to the respective proga Y and. 6. Thereforef-the II frequency corresponding-to point D, may be adjusted-by" wave amplifier or oscillator tube, on one hand, or of the backward wave oscillator, known under the name of Carcinotron (registered trademark) on the other hand, the structure diagrammatically shown in Fig. 2 may be used to build up either an amplifier or an oscillator. In the case of an amplifier, a Wave of a given frequency is fed to the delay structure 1 and the velocity of beams 3 and 6 is adjusted to this frequency. In the case of an oscillator, the velocities of beams 3 and 6 determine the oscillation frequency. Of course, in each case, the tube, only a few components of which are shown in Pig. 2, must comprise the whole of the necessary structure in accordance with known technique.

An amplifier according to the invention will now described.

Referring to the general diagram in Fig. 2, it is seen that the energy to be amplified may be fed to the structure 1 either in the direction of collector 4, or in the direction of collector 9. This energy propagates in network 1 in any direction, determined only by the structure of the network. As already mentioned, the respective velocities of beams 3 and 6 must be adjusted so as to be, respectively, in synchronism with the components of the wave to be amplified along the directions Ox and y.

An embodiment of an amplifier tube according to the invention is shown, by way of example, in axial crosssection in Fig. 3. The transversal section of this tube is the same as that of the tube of Fig. 9.

In this example, the delay network 1 of Fig. 2 has been rolled up to form a cylinder, the generatrix of which is parallel to Ox. In this way, two opposed edges of structure 1 are coupled to each other and standing waves are established in the direction of 0y, i. e. circularly in each transverse cross-section of the cylinder, whereas propagation in the axial direction is effected in traveling waves. As shown, the network comprises an array of vanes 20, carried by the wall of a cylindrical metal envelope 21. Thus, the network defines a wave guiding system having a plurality of adjacent uniform and uniformly spaced parallel ducts surrounding a central duct with which they communicate. Along the axis thereof is located a cylindrical cathode carried by a sleeve 22, inside which is located the heating filament, whose ends protrude at the end 23. An axial magnetic field is produced by a coil 24. The field intensity is such that the electrons originating from cathode 5 have their respective paths sufl'iciently bent not to land on the vanes 20. As may be seen from Fig. 9, beam 6 of Fig. 1 is, in his case, formed by an electron cloud propagating around the axis of the tube and parallel to a cross-sectional plane i. e. in the direction Oy.

The tube comprises, in addition, several electron guns, three in the embodiment shown, 2', 2", 2", which project three parallel elementary beams 3, 3", 3" focused in the direction Ox by the axial field formed by coil 24. This group of beams is equivalent to beam 3 in Fig. 2. The guns are fed by connections 25, and electrons, accelerated by anode 26 connected to envelope 21, are projected into the space between cathode 5 and vanes and collected by collector 4 at the end of their trajectory.

A number of vanes 27, located in an intermediate zone of the delay network in the axial direction, are, according to a known technique, coated with an attenuating substance for the purposes well known in the art.

The tube is fed by sources 30 and 32 as in Fig. 2.

Cathode 5 extends between the end of the attenuated portion 27 and the collector 4. Accordingly, the tube operates as a conventional traveling wave amplifier in the portion comprised between the input and one end of the attenuated portion 27, and as an amplifier according to the invention between the other end of this portion and the output of the tube. The strapping system, shown in Fig. 4, comprises conductors 29 respectively connected to all the vanes of the same row. The ends '4 of conductors 29 alternatively connected, on one side, to one of the conductors of the pair of conductors 28, and, on the other side, to one of the conductors of a pair of conductors 31. It is known that, in this way, the propagation of direct space harmonics is promoted.

The energy to be amplified is fed to the input 28 of the tube and is extracted at the output 31. As shown, both the output and the input are in the form of bifilar lines connected to strapping 29.

Two oscillators according to the invention will now be considered by way of example. It has already been mentioned that for a given velocity of one of the beams, a plurality of oscillation frequencies may be obtained. The frequency of the oscillation produced is positively selected only when the propagation velocities of the two beams are determined.

Figs. 5 to 7 show a first embodiment of the oscillator according to the invention. The bidirectional network 1 comprises a postively biased electrode plate 12 carrying parallel rows of fingers 13, and a plane negative electrode 14, electrically connected to cathode 2 and parallel to plate 12. Electrodes 2, 12 and 14 are carried by rods 15, sealed in the insulating walls of envelope 16. These rods may serve as leads in connections for the supply circuits. Cathode 2 is adapted to produce a plurality of parallel beams, forming together laminar beam 3. These elementary beams are projected between the rows of fingers 13. Collector 4 of beam 3 is shaped as a metal block and is part of the vacuum tight envelope E of the tube. The output wave-guide 11 is closed by an insulating window 17. Pole pieces 18, 19 generate a magnetic field, the lines of force of which are parallel to the beam 3 and perpendicular to beam 6. When a negative potential with respect to electrode 12 is applied to electrode 14, an electric field perpendicular to the magnetic field is produced between these electrodes. This electric field is concentrated between the end of fingers 13 and electrode 14'. It is substantially zero in the spaces between the fingers. Thus, beam 3 is focused by the magnetic field. Beam 6 propagates in the space comprised between the ends of the fingers and electrode 14, normally to crossed electric and magnetic fields. It is fed into this space by means of a suitable electronic optical device, of any known type, as is well known in the art.

It should be noted that in the oscillator of Figs. 5 and 7 energy propagation may take place either in traveling waves in both directions, or in standing waves in both directions or in traveling waves in one direction and in standing in the other.

If the oscillator is caused to operate with standing waves, reflecting means must be provided along the correspondlng edges of the delay structure. For instance, if standlng wave energy is caused to interact with beam 3, reflecting planes, diagrammatically shown by dash-lines at R and R in Fig. 7, should be provided. Similarly, planes Ra and R'a could be provided in the direction of the beam 6, or plane Ra could be provided alone while the output should be substantially mismatched, the effect being of course the same.

When energy is propagated in traveling waves the interaction could occur either in the direct or in the reverse mode. In the last case, absorbing means should be provided at the collector end of the beam in accord ance with the practice described in a copending applicatron, Serial Number 281,347, filed April 9, 1952, in the name of B. Epsztein, assigned to the same assignee. Such absorbing means could be located in the vicinity of the inner face of block 4, as diagrammatically shown at A and B, in the case of beam 3 and beam 6 respectively.

Of course, the tube, as shown, could be used as an amplifier with the energy fed at 11' and extracted at 11. Whatever the operation of the tube may be the main feature remains the provision of an at least bidimensional delay structure cooperating with at least two beams.

Figs. 8 and9 illustrate, respectively, in axial and transversal cross sections; a further embodiment of theoscillator according to the invention. The design of this oscillator is broadly thesame as that of the amplifier in Fig. 3. However, there is, of course, no input connection provided. The output connection 31 is located in the vicinity of the cathodes 2, 2", 2". The end of the delay structure is attenuated in the axial direction for the reasons pointed out above. Oscillation along this direction, is by interaction of beams 3, 3", 3" with an inverse space harmonic. The bifilar output 31 is connected to strapping wires 29, the latter being connected according to the wiring diagram of Fig. 8, showing the array of vanes 20. Straps 29 are alternately connected to the vane 20 of the twoadjoining rows. Experience shows that this strapping enhances the propagation of a strong inverse space harmonic;

The system formed by beams'3', 3", 3 and the delay structure operates as a backward wave oscillator;

The system formed by cathode 5 and the delay structure can be compared to a magnetron. It is tightly coupled to output28 through straps 29, and it will behave as an amplifier with respect to the oscillations generated by beams 3', 3" and 3".

As pointed out before, many other embodiments could be provided without departing from the scope and spirit of the invention, the essential feature being always the provision of an at least 'bi-dimensional delay structure cooperating with at least two mutually intersecting beams.

In particular it is to be noted that three beams propagated in three intersecting directions by means of a three dimensional delay structure could be used. The operation of a tube provided with a three dimensional, or three directional, delay structure is basically the same as the operation of a tube having a bi-dimensional structure.

The advantages of the invention may be summarized as follows:

It is an advantage to use a bi-dire'ctional delay structure because a larger beam current can be used than in a simple delay line.

The presence of a second electron beam increases the power and the efficiency.

The necessity of 'a second electron beam has been shown here when the frequency is defined by the velocity of the beam or beams, i. e. when there is a distributed feedback through backward Wave operation.

If the frequency is defined by the circuit, i. e. when there are standing waves in all directions, there will be a problem of mode competition and the second beam will help to favor a desired mode;

If the amplifier of this application is compared to the amplifier of copending application, Serial No. 557,099, filed January 3, l956,'the second beam represents a way to obtain a sequence of gain according to the direction of propagation inside the tube. Then attenuation can be used as in conventional traveling wave tubes, instead of having to use unidirectional, for example ferrite, attenuation.

If the amplifier according to this application is compared to a conventional traveling wave tube, it has the advantage of allowing magnetron type interaction with the second beam, normal to the propagation of energy, with the high efliciency that a magnetron is known to have.

What is claimed is:

1. In an electron discharge tube, a delay transmission structure having distinct paths for: delayed energy to propagate therein in mutually intersecting directions, means for directing respectively distinct beams of electrons along said paths to interact with energy therein, and output means coupled to said delay structure.

2. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; first electron emissive means positioned for propagating electrons in said first direction in coupled relationship with said structure for interaction with energy propagating therein; second electron emissive means positioned for propating electrons in said second direction in coupled rela tionship with said structure for interaction with energy propagating therein; and output means coupled to said structure for abstracting energy propagating therein.

3.An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; first electron emissive means positioned for propagating electrons in said first direction in coupled relationship with said structure for interaction with energy propagating therein; second electron emissive means positioned for propagating electrons in said second direction in coupled relationship with said structure for interaction with energy propagating therein; collector means for collecting the electrons propagated along at least one of said directions; and output means coupled to said structure for collecting energy propagating therein in at least one of said directions.

4. A tube accordingto' claim 2 wherein said output means comprise collector means positioned for collecting electrons propagating in said second direction.

5. An ultra high frequency discharge tube comprising: a delay structure whichis' geometrically periodical along first and second mutually intersecting directions; first electron emissive means positioned for propagating electrons in said first direction in coupled relationship with said structure for interaction with energy propagating therein; second electron emissive means positioned for propagating electronsin said second direction in coupled relationship with said structurefor interaction with energy propagating therein; means for propagating said energy in one of said directions in traveling waves; means for propagating said energy in standing waves in the other of said directions, and output means coupled to said structure for abstracting energy propagating therein at least in said one direction.

6. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second' mutually intersecting directions; first electron emissive means positioned for propagating electrons in said first direction in coupled relationship with said structure for interaction with energy propagating therein; second electron emissive means positioned for propagating electrons in said second direction in coupled relationship with said structure for interaction with energy propagating therein; matching means for causing energy to propagate in traveling waves along at least one of said directions and output means coupled 'to said structure for collecting energy propagating therein.

7 An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; input means for feeding energy to said delay structure; first electron emissive means'positioned for propagating electrons in said first'direction in coupled relationship with said structure for interaction with energy propagating therein; second electron emissive means positioned for propagating electrons in said second direction in coupled relationship with said-structure for interaction with energy propagating therein; collector-means for collecting the electrons propagated along at least one of said directions, and output means coupled tosaid structure for abstracting energy propagatingutherein along at least said second direction. I

8} An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; input means for feeding energy to said structure; first and second electron emissive means positioned for propagating electrons respectively in said first and second directions in coupled relationship with said structure for interaction with energy existing therein; means for propagating energy in standing waves along one of said directions; means for propagating said energy in traveling waves along the other direction, and output means coupled to said structure for extracting energy propagating therein.

9. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; input means for feeding energy to said delay structure; first and second electron emissive means positioned for propagating electrons respectively in said first and second directions in coupled relationship with said structure for interaction with energy existing therein; collector means for collecting electrons along one of said directions; and output means for abstracting traveling wave energy propagating along at least one of said directions.

10. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; first and second electron emissive means positioned for propagating electrons respectively in said first and second directions in coupled relationship with said structure for interaction with energy existing therein; means for propagating said energy in standing waves along at least one of said directions and means for abstracting energy from said tube at least along one of said directions.

11. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually intersecting directions; first and second electron emissive means positioned for propagating electrons respectively in said first and second directions in coupled relationship with said structure for interaction with energy existing therein; means for propagating said energy in traveling Waves along at least one of said directions; and output means for abstracting energy from said tube.

12. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually perpendicular directions; a plane electrode extending along said delay structure; terminal connections for providing an electric field between said delay structure and said electrode; first electron emissive means positioned for propagating electrons in said first direction; means for providing a magnetic field normal to said electric field and parallel to said first direction; second electron emissive means positioned for propagating electrons in said second direction; collector means for collecting the electrons propagated along said first direction; and output means coupled to said structure for abstracting at least the energy propagating along said second direction.

13. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually perpendicular directions and has its ends mutually uncoupled in said first direction and mutually coupled in said second direction; first electron emissive means positioned for propagating electrons in said first direction; means for providing a magnetic field having its lines of force extending in said first direction; second electron emissive means positioned for propagating electrons in said second direction under the action of said magnetic field; collector means for collecting the electrons propagated along said first direction; and output means coupled to said structure for abstracting at least the energy propagating along said first direction.

14. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually perpendicular .directions and has its ends mutually uncoupled in said first direction and mutually coupled in said second direction, to form a wave guiding system having a plurality of adjacent uniform and uniformly spaced ducts surrounding a central duct and communicating therewith; an elongated cathode extending over at least a portion of said central duct for emitting electrons; magnetic means directing said electrons along said second direction; a plurality of cathodes positioned for emitting electrons in said first direction; and output means coupled to said structure for abstracting at least the energy propagating therein along said first direction.

15. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually perpendicular directions and has its ends mutually uncoupled in said first direction and mutually coupled in said second direction, to form a wave guiding system having a plurality of adjacent uniform and uniformly spaced ducts surrounding a central duct and communicating therewith; an elongated cathode extending over at least a portion of said central duct for emitting electrons; means for providing a magnetic field for directing said electrons along said second direction; a plurality of cathodes positioned for emitting electrons in said second direction, said cathodes being positioned at one of the uncoupled ends of said structure and said elongated cathode extending from the other uncoupled end of said structure over at least half the length thereof; input means coupled to said structure at the end thereof adjacent to said plurality of cathodes and output means coupled to said structure at the opposite end thereof; and absorbing means in the ultra high frequency field of said structure in the intermediate portions thereof.

16. An ultra high frequency discharge tube comprising: a delay structure which is geometrically periodical along first and second mutually perpendicular directions and has its ends mutually uncoupled in said first direction and mutually coupled in said second direction to form a wave guiding system having a plurality of adjacent uniform and uniformly spaced ducts surrounding a central duct and communicating therewith; an elongated cathode extending over at least a portion of said central duct for emitting electrons along said second direction; means for providing a magnetic field having its lines of force extending in said first direction for directing said electrons in said second direction; a plurality of cathodes positioned for emitting electrons in said first direction, said cathodes being positioned at one of the uncoupled ends of said structure and said elongated cathode extending from the same end of the structure over at least a portion thereof; output means coupled to said structure at the same end thereof; and absorbing means in the ultra high frequency field of said structure at the opposed end thereof.

17. In an electron discharge tube, a delay transmission structure having distinct parts for delayed energy to propagate therein in different directions, two electron beam means, and means for propagating said two electron beam means in operative relationship with said delay transmission structure to provide velocity components of said beam means in said directions.

References Cited in the file of this patent UNITED STATES PATENTS

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