US2595677A

US2595677A - Electron discharge device

Info

Publication number: US2595677A
Application number: US29568A
Authority: US
Inventors: Russell R Law
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1948-05-27
Filing date: 1948-05-27
Publication date: 1952-05-06
Anticipated expiration: 1969-05-06

Description

Big/5%:OR

4 Sheets-Sheet l R. R. LAW

ELECTRON DISCHARGE DEVICE V CON 5= P05, 0.6.

U 19.6. INPUT 7 19-6. OUTPUT May 6, 1952 Filed May 27, 1948 ATTRNEY May 6, 1952 R. R. LAW

ELECTRON DISCHARGE DEVICE 4 SheetsSheet 2 Filed May 2'7, 1948 @W 2 RN x mm A mm v W SQ E Kw. w A Wm g W Q .1 I -wQNJ m E s 111111111111111111111111111111111111111111 z! fi Q \m S g 3 A T & 5 z m m m Q i Q R \QN aw 3 m 8w Qw N x f a 2 4 \NQ Qw W L QM Filed May 27, 1948 4 SheetsSheet 5 INVENTOR M y 6, 1952 R. R. LAW 2,595,677

ELECTRON DISCHARGE DEVICE Filed May 27, 1948 4 Sheets-Sheet 4 mvENToR lgezmllllw Patented May 6, 1952 2,595,677 ELECTRON DISCHARGE DEVICE Russell R. Law, Princeton Township, Mercer County, N. J., assignor to Radio Corporation oi America, a corporation of Delaware Application May 27, 1948, Serial No. 29,568

20 Claims. (01. 315-5) In this application, I disclose a new and improved electron discharge device structure and a novel manner of putting the same to use in alternating current circuits.

The electron discharge devices of my invention are useful in the electronic and related arts, and are of particular use in handling alternating current voltages and currents falling in the higher frequency range.

A primary object of my invention is to provide an electron discharge device capable of generating considerable power of substantially uniform magnitude throughout an extremely wide band of frequencies. The power generating device of my invention may be self or separately excited. In the embodiment being described it may be either separately or self excited.

In known systems as the wavelengths handled are shortened, the electron discharge device electrode dimensions must be taken into account since they become important parts of the resonant circuits used with the devices and may provide asymmetrical and improper operation of the electron discharge device electrodes. Thus, as the frequencies to be handled go up, the device structure and electrode dimensions must be reduced and this entails a reduction in the power which can be generated in the devices either as a result of self or separate excitation.

A further object of my invention is to provide a device structure so arranged that the dimensions of the elements thereof which determine the operating frequency may be compressed or reduced to extremely small proportions without correspondingly reducing the power rating of the device. The electron discharge device of my invention is especially well adapted to generation of high power at higher frequencies than structures known in the prior art. Considered from another viewpoint, the electron discharge device of my invention provides more power at a given frequency of operation or operation at higher frequencies with a given power rating than devices known heretofore.

An additional object of my invention is to pro vide an electron discharge device structure as described in the preceding paragraphs, which is extremely rugged and of long life in operation.

In its broadest aspect my electron discharge device structure comprises a composite cathode made up of a plurality of spaced emitting areas separated from each other by non-emitting areas all in a surface. The emitting areas face the grid electrode and the non-emitting areas separating the emitting areas'are dimensioned, and shaped if desired, toform with the cathodeto grid capacity and grid dimensions a tuned circuit in the form of a cathode to grid cavity. My novel anode structure comprises a like number of spaced electron collector areas in a surface reached by the electrons from the emitting areas after passing through the grid. The active collector areas are in a like manner separated by inactive areas dimensioned, and shaped if desired, to form with the anode to grid capacity and grid dimensions a tuned circuit in the form of an anode to grid cavity. The active anode and cathode areas may have considerable length in a direction at right angles to the frequency determining dimension so that considerable power is provided without lowering the frequency of operation. Moreover to enhance this same end result the number of emitting areas and collecting areas may be increased without increasing dimensions critical to the frequency of operation.

In a specific embodiment the emitting areas and collecting areas are in the surfaces of cylinders separated by the grid electrode. An even number of emitting and collecting areas are provided and each collector area faces its corresponding emitting area through the grid. The active areas are spaced each from the other by arcs which are measured by equal angles.

A further object of my invention is to provide novel couplings to the tube electrodes of my invention to make the best use of its ability to generate considerable power uniformly in awide frequency band.

Where the tube is to be used as an amplifier the input circuit is connected to alternate emitting areas and the output circuit is coupled to alternate collector areas and the emitting areas and collector areas to which coupling is made are staggered, or, not in register, and if necessary neutralizing capacitors are added. If regeneration is desired the elements are connected "in register" and the capacity within the tube through which feed back can take place is supplemented by, added capacity, and regeneration can be built up to make the tube act as a selfexcited oscillation generator.

In the specific embodiment described above a coaxial line has its outer member coupled to tube structure operating at low radio frequency voltage and its inner member terminated in a ring coupled to alternate emitting areas. The output circuit of the device is another coaxial cable with the outer member at low radio frequency voltage and the inner member coupled to alternate collector areas. These rings also take part in supporting the cathode and anode structures.

' A further object of my invention is to provide means to neutralize, over-neutralize, or underneutralize the capacity between the emitting and collector areas. This object is attained by providing as a support for the grid a ring member intermediate the rings described above for the anode and cathode structures and providing said intermediate ring with apertures to provide coupling therethrough between the emitting areas and collector areas as desired.

A further object of my invention is to provide an electron discharge tube of the character described above including means for readily changing its frequency of operation. This object is attained in accordance with my invention by putting the emitting areas, grid and collector areas in parallel surfaces which are at a small angle with respect to the tube axis. Movement of the electrodes, relative to each other, along the tube axis changes the spacing between the emission and collector electrodes to change the dimensions of the tuning area and in particular to change the size of the capacitors in the circuits and thereby change the frequency of operation.

In an embodiment the emission areas, grid and collector areas are in the surfaces of telescoped truncated cone like cylinders so that relative movement thereof along their axis changes the distance between the electrodes and the tuning of the series resonant circuits in the form of cavities.

I believe that those skilled in the art will understand my invention and the'manner in which it is put to use from the brief description given above. However, I have described my invention in detail hereinafter. This detailed description includes reference to the attached drawings wherein Figures 1 and 2 are schematic diagrams of an electron discharge device constructed in accordance with my invention.

Figure 3 is a sectional view through the longitudinal axis of the device.

Figure 4 is a cross section view on the line 4-4 of Figure 3.

Figure 5 is a perspective view of the cathode assembly and mounting;

Figure 6 is an exploded perspective view of the end disc for the cathode to which the alternate current circuit may be connected; the anode end disc to which the high frequency circuit may be connected; and the grid end disc between said above discs, said grid disc having apertures therein through which a selected amount of coupling between cathode and anode takes place: While Figure 7 shows the electrodes in another embodiment of my tube and the manner in which they are relatively moved to change their spacing and tuning.

In its broadest aspect my electron discharge device comprises as illustrated in Figures 1 and 2, a grid electrode ID, a cathode electrode 12 having a plurality of electron emission areas K separated by inactive areas IK. The anode structure l4 comprises a plurality of electron collector areas A separated by inactive areas IA. The active anode and cathode areas may be of considerable width and length and they face each other or are in register through the grid H1. The cathode may be composite having several sections as will be seen hereinafter. Thus there is considerable capacity coupling between the active areas and the grid and this taken with the electrode dimensions forms a series of resonant circuits series tuned to the frequency of operation. More specifically, the cathode dimensions measured by the arrows 3 and 5 taken with the two capacities C, each of which is equal to one. half the capacity between an active cathode area and the grid, form a series resonant circuit that determines the frequency of operation. This circuit is then as represented at 22 in Figure 2. In this figure, C equals one-half the capacity between the active emission areas and the grid; L is the inductance of the cathode area measured by arrow 3 and L is the inductance of the grid surface measured by arrow 5. These surfaces may also be considered to form a cavit resonator between each pair of active collector areas and the grid. Thus we have a series of resonant cavities in series, each of which cavities is series resonant at a frequency determined by its dimensions which dimensions are not increased when the number of active areas or the dimensions there of are increased. The anode structure forms similar resonant circuits or cavity resonators as has been shown at 25 where L", Figure 2, represents the inductance of the anode surface measured by the arrow 3' of Figure 1. C represents one-half the capacity between each active anode area and the grid.

In operation, a driving voltage may be impressed (Figure 1) by the inner conductor of a coaxial line 30 on alternate active cathode areas K. Then the grid l0 and the outer conductor of line 30 may be at ground or low radio frequency potential and the device operates as a separately excited cathode driven stage. Output may be taken by a second coaxial line 32, the inner conductor of which is coupled to alternate collector areas, the outer conductor of the line being coupled to the grid. When considerable capacity between the active cathode and anode areas is desired, the active areas to which the couplings are made may be in register and capacitance NC added. Such an arrangement is indicated in Figure 2 where the active cathode areas, driven by alternating current applied at points U, are in register with the active anode areas coupled at points V to the output circuit. When less coupling is desired the active areas to which the couplings are made ma be staggered. In Figure 2 bias or modulation or both are applied at the points T, positive direct current potential to the points S and negative direct current potential to the points Z.

The showing in Figures 1 and 2 are to a large extent symbolic. In practice the active cathode areas may be in a closed path and the active collector surfaces are in a similar path separated from the first path by the grid electrode. In an embodiment the paths are in the surfaces of cylinders.

As to the respective cathode and anode active areas, they operate differentially in the alternating current circuits, adjacent ones thereof operating in displaced phase relation and alternate ones thereof operating at like alternating current phases. Thus the excitation circuits to and from these areas are connected to alternate areas. With respect to direct current potentials and modulation, the active areas of each of the anode and cathode are as one. By coupling back in known fashion the tube is caused to generate oscillations. For example, the capacity NC, Figure 1, may be dimensioned as will appear hereinafter to set up regeneration which is carried to a point at which oscillations are generated. On the other hand, thecapacitor NC may be dimensioned to neutralize the anode to cathode capacity to facilitate operation as an amplifier.

A specific embodiment of my device is shown in Figures 3, 4, 5 and 6. In these figures, the cathode is designated K, K, and K" and 'Is movably mounted on a cylindrical member 90 as will be described in detail hereinafter. The cathode faces the anode through the grid 50 mounted on the support 52. 54. The anode areas or members have been labelled by the numeral 200 and are mounted on the support 204. The partially exploded, partially sectioned end perspective of Figure 6 and the perspective of Figure 5- shows the general arrangement of the device electrodes clearly. The electron discharge device will now be described in full detail.

In this embodiment, my device comprises as illustrated in Figures 3, 4 and 5 a grid electrode in the form of parallel wires 50 which have for a support a metallic cylinder 52 somewhat flared as at 54 at one end. The metallic cylinder per se is opened at the other end with a shoulder 56 into which a grid disc 60 is soldered after the cathode which will be described hereinafter is assembled. The cylindrical support 52 is recessed or windowed as shown at 62 in Figure 3 and Figure 6, there being a window for each active anode and cathode area. The support 52 also takes part in supporting the cathode structure which is insulated therefrom and is described hereinafter. The cathode and anode areas face each other from opposite sides of the grid, the electron path being through the windows 62 from each emitting surfacev to its opposite electron collecting surface. The dimensions of the windows are larger than the active anode and cathode areas. The grid 50 is formed by winding a metallic wire or ribbon in grooves around the outer periphery of the member 52-54. The flared end 54 of the grid support is integral with a copper ring or flange like member 64. The joint between support 54 and ring 64 may be soldered and is to be a good electrical and heat conductor but is not under vacuum pressure.

The copper ring 64 serves as the base member to which two flexible

Kovar metal members

60 and 68 are fastened by copper rings I and I2.

The

Kovar metal members

66 and 68 have several functions. They are useful for bonding metal to glass being a metal having a coefficient of expansion similar to the coeflicient of expansion of glass and are bonded to the annular bands I4 and I8 of glass which form a part of the tube closure structure and also provide insulation between the grid structure and the anode and cathode structures. Since the Kovar members are flexible they permit some relative axial movement of the electrodes to take place. The copper rings 64, I0 and 12 may be fastened together in various manners. Preferably a gold wire is placed between these members at the points marked with Xs and high pressure is applied and the heating used during baking serves to fuse the joints between the gold wire and the copper rings. It has been found that these joints are clean and provide good vacuum pressure proof bonds between the rings.

The cathode structure comprises a cylindrical member 90 having grooves 94 in the outer periphery thereof. The grooves 94 provide means for extending heater wires 95 from a point outside of the tube closure member to the cathode heating elements adjacent the cathode emitting surfaces. There is a groove 94 then for each,

cathode structure and these grooves are separated by equal arcs on the periphery of the cylindrical member 90. The cathode elements are movably mounted on the left hand end of the cylinder as seen in Figure 3. A second cylinder or sleeve 96 is slipped over the other end of the cylinder 90 to enclose the cathode heater wires for protection and shielding thereof and to prevent short circuiting of the same against the tube supporting members through which the cathode heating circuit return is made. The

cylinders

90 and 96 are joined with a heavy copper flange-like ring 98 to which the

cylinders

90 and 96 are'soldered, with the cylinder 96 abutting the inner face of the ring 98 and the cylinder 90 extending through and abutting the inner periphery of the ring 98. An eyelet. 99 is sealed through a metallic cover I00 sealed to the ring-98. This eyelet is of Kovar and supplies an aperture through which the filament heating lead is passed and also serves as a bond between the closure member and the glass bead through which the filament heating lead 95 passes. The cathode supporting ring 98 cooperates with an additional copper ring I02 to retain in place in sealed relation a flexible ring I04 made of Kovar and arranged to complete the closure member by being bonded into the glass annular band I8. A cross section through the cylinder 90 and cathode structure is shown in Figure 4. The cylinder 90 in addition to being grooved at 94 for the filament leads 95 also has a plurality of longitudinal channels I08 along the axial length of the cylinder extending from the cathode end down along the cylinder a distance about equal to the length of the plurality of cathode emitting surfaces. Each emitting area is connected to member 90 by flexible members I09 and H0 which are held in position by fixed cathode connector' clamp bars H2. These flexible members I09 and H0 permit radial movement of the cathode structure to adjust the distance between the emitting surface and the grid 50 disposed around the outer surface of the emitting areas.

Referring now to Figures 4 and 5, the copper cylinder 52-54 described hereinbefore as the grid support is recessed at 62 to permit the cathode structures to extend into the cylinder 52-54 toward the grid, and serves as a support for and means for adjusting the radial position of the emitting surface. The ring 52-54 has threaded openings at II8 therein at opposite sides of each cathode structure. Pairs of threaded plugs I20 are arranged to be threaded into the openings H8. The plugs I20 are drilled to take bolts I24 which are threaded into ceramic base members I30 there being two base members for each emitting area structure. I30 are fastened to the plugs I20 and it will be obvious that by loosening the bolts I24 the plugs I20 may be moved radially by rotation thereof to adjust the position of the ceramtc supports I30. Each of the cathode emitting areas comprises an outer conductor I36 spot welded to an inner conductor I38 and the outer conductor I36 is spot welded to a plurality of rod or wire like stand off members I38 for each conductor I38. The stand off members I38 are spot welded to a cross member I40 which is fastened by bolts I42 to the ceramic support I30. The flexible members I09 and H0 are spot welded to the cross members I40. The cathode emitting areas each comprise three sections K, K, K" shown. in

The ceramic supports Figure 3. More sections or fewer sections may be used. One section only has been described in connection with Figure 5 because the several sectionsare similar. The members I09 and H are partially folded strips as shown clearly in Figures 4 and 5 having an axial dimension of the order of the dimension of the total electron emitting areas and serve the additional function of shielding the cathode heating circuit leads which .pass through the grooves 94 and go to heating elements I50 between the upper and lower cathode conductors I36 and I38. To increase the flexibility of the members I00 and H0, they may be slotted as shown in Figure 5.

As shown hereinbefore the cathode emitting surfaces are insulated from the grid member and its supporting structure by the ceramic supports I30. The cathode emitting surfaces and grid may therefore be connected into circuit as desired.

In the-embodiment illustrated, a cathode connecting ring I60, Figures 3 and 6, has points on the outer periphery thereof connected to each cathode emitting area or to alternate ones thereof. This flange like ring I60 has tabs I64 (Fig. 3) spaced around the periphery thereof which are connected to the cathode emitting areas. The member I60 is a ring like member with a hole in the center thereof and has bolted thereto by bolts I a member I66 which closes the cylindrical inner end of the inner member IL of an input coaxial line. The member I66 has a shoulder I68 formed thereon which is sealed into the end of the cylindrical member IL and this joint is made by silver soldering the member I60 to the member IL. The bolts I10 are silver soldered into place to form a portion of the wall of the electron discharge device closure member which is evacuated. The line II is the inner member of a coaxial line the outer member OL of which is silver soldered to the copper end cover I00. The outer member CL of the coaxial line is spaced from the inner member IL by glass spacer I'I2 sealed thereto.

The electron collecting areas or members 200 of the anode are soldered into recesses 202, Figures 4 and 6, of a copper cylindrical sleeve like member 204. The sleeve like cylindrical member 204 is sealed by fusing as described hereinbefore to a copper ring 206 and the ring 200 has soldered thereto a flexible Kovar metal member 208 which is sealed into the glass annular band 14 to form a part of the closure member for the device and toinsulate the'anode electrode structurefrom the grid structure. The assembly here at the point X is similar tothat used with the rings I02 and 98 and involves placing a gold wire between the surface of the cylinder 204 and the ring 206 and applying pressure thereto to fuse the gold to the copper..

The sleeve like member 204 is closed at its outer end by a disc like ring 2I4 soldered on to the end of the member 204. The disc like ring is apertured to the extent necessary to support the flanged cylindrical member 2I6 which is silver soldered to the member 2I4. The cylindrical member 2I6 forms the outer member of an output coaxial line and also a wall of the electron discharge device. Ihe inner member 220 of this coaxial line is cup-shaped in that it is flanged inwardly at the inner end to form a circular area wherein bolts 224 may be placed to bolt this member to a cup-shaped member 226. The joint between the

members

220 and 226 and the heads of the bolts 224 are silver soldered. The inner conductor 220, glass separator 'bea'd 209. the outer conductor 2 I6 and the member 2I4 form a part of the electron discharge device electrode closure member in which the high vacuum is maintained. The member 226 is ring like at the eifd bolted to the member 220 and has the other end thereof flanged inwardly with tabs 230 which are bolted to the electron collector elements 200 or alternate ones thereof. In the embodiment described there are 12 electron collector electrodes and a corresponding number of composite electron emission electrodes with a corresponding number of windowed recessesin the copper cylindrical support 52 for the control grid.

The electron discharge device of myinvention will as stated above develop considerable power and means for cooling the same is provided. This means comprises a radiator 240 for the anode, a radiator 250 for the control grid and a radiator 260 for the cathode. The radiators comprise cylindrical like

member

242, 252 and 262, respectively, to which are fastened by soldering or as desired a large number of radiating

fins

244, 254 and 264. The

cylindrical members

242, 252 and 262 are slid over the tube structure with cylinder 242 fitting snugly over the cylindrical like member 204, cylinder 252 fitting snugly over the outer periphery of copper rings '64, I0 and I2 and cylinder 262 fitting in like manner over the outer periphery of copper ring I02; disc like ring and the end cover I00. Air'is circulated through the fins to reduce by convection heat conducted thereto by the electron discharge device electrodes. The entire tube structure is enclosed in a Bakelite tube 25I. To retain the radiator fins properly spaced, the outer edges thereof are notched at N and a wire is wrapped around the fins in the notches and soldered to each fin. The air flow or circulation is as desired but may enter as indicated by the arrow labelled air in and may leave the tube structure as indicated by the arrow labelled air out."

The grid disc 60 interposed between the members 226 and I60 is apertured as shown at 6I to provide coupling NC between the anode and cathode as desired to under, to over or to exactly neutralize the coupling between the anode and cathode through the grid.

It will be understood that by describing a speciflc embodiment and listing the dimensions of critical parts thereof as I have done hereinafter. I do not propose to thereby limit the scope of my invention. In the embodiment being described, the electron emitting areas are in the surface of a cylinder having a diameter of 5". The active anode areas are in the surface of a cylinder having a diameter 5.088 and the grid electrode is centered on a cylindrical surface 5. in diameter. The grid has a thickness of .007" and is spaced from the cathode about .010 and from the anode about .080". The windows in the grid support are each large enough to provide clearance for an active cathode area about 3.0" long and about .50" wide. The active anode collector areas are about 3.093 long and .600" wide. The depth of the recesses between the active anode and cathode areas are taken into consideration in determining the natural frequency of the cavities or resonant circuits of Figures 1 and 2. A1- lowances are made for the differences in diameters of the collector areas and emission areas.

A modification of my arrangement as described above is shown schematically in Figure '7. This figure shows one side of across section through a tube axis having tube electrodes as described hereinbefore arranged in a novel manner for easy natural frequency of operation of the system.

Reference numerals corresponding to those used in the prior figures are used insofar as possible. In Figure 7, 52 is the support for the

grid

50, 90 is the support for the cathode structure K-- K while 204 is the support for the anode structure 200. The cathode support 90 is mounted by bellows like members 68' and H14" in the tube structure, being insulated from the grid support 52 by'glass rings 18' and 18". The anode support 204 is mounted in similar manner by

bellows

208 and 208" in glass rings 14 and .14". As mounted the active areas of the anode, the grid and the active areas of the cathode lie in the surfaces of truncated hollow cones.

Movement of the electrodes or one thereof along the axis of the cone changes the spacing of the electrodes to change the operating characteristics of the electron discharge device. The anode or cathode structure or both may be moved along the tube axis as denoted by the arrows 90 and 204'.

What I claim is:

1. An electron discharge device, comprising a control electrode, two electron emitting areas at one side of said control electrode, a conductive surface joining said areas and forming with said control electrode a cavity resonator, two electron collecting areas at the other side of said control electrode and. a conductive surface joining said last named areas and forming with said control electrode a second cavity resonator.

2. An electron discharge device, comprising a control electrode, two-electron emitting areas adjacent said control electrode and a conductive.

surface joining said areas and forming with said control electrode a cavity resonator.

3. A cathode structure including two spaced thermionic electron emitting areas joined by a conductive element which forms a cavity resonator coupled between said areas.

4. An electron discharge device comprising a cathode having a plurality of electron emitting surfaces separated by non-emitting surfaces, an

ano e electrode compris ng a plurality of electron.

collector surfaces separated by non-collecting surfaces, a control electro e in the path of emission of said cathode, couplings connecting alternate emission surfaces for driving said device, and an output line coupled to said collecting surfaces.

5. An electron discharge device, comprising a cathode having a plurality of electron emitting surfaces separated by non-emitting surfaces, an anode e ectrode comprising a plurality of electron co lector surfaces separated by non-collecting surfaces. a ri electro e in the path f emission of said cathode, a coupling connecting said emission surfaces for driving said dev ce and an output line coupled to alternate collecting surfaces.

6. An electron discharge device comprising a cathode having a plurality of electron emitting areas separated by non-emitting areas, an anode with a like number of electron collecting areas separated by non-collecting areas, a grid electrode disposed between said cathode and anode, said emitting areas and collecting areas being in register-one with the other, and tuned circuits for said electrodes including alternating current .10 couplings connected to alternate emitting areas and to alternate collecting areas.

7. An electron discharge device including. a grid electrode, a cathode structure comprising a plurality of spaced emission areas facing said grid electrode, and an anode structure comprising a like number of electron collecting areas spaced apart by conductive surfaces facing said cathode areas through said grid electrode, said conductive surfaces being joined with said collecting areas and forming with said grid electrode a cavity resonator coupled between each pair of adjacent collecting areas.

8..A device as recited in claim 7(furtherineluding mean comprising other conductive surfaces connected between each pair of adjacent electron emitting areas for setting up on alternate emitting areas alternating potentials of a frequency determined in part by the spacing between said emitting areas.

9. An electron discharge device, comprising a cathode structure comprising an even number of emitting areas on the periphery of a closed path, a support for said areas comprising recessed surfaces between the areas, the dimensions of which recessed surfaces determine in part the natural frequency of operation, a grid structure forming a second closed path on one side of said first path which is equidistant throughout its length from said first path, an anode structure comprising an even number of electron collector areas, there being one collector area for each emitting area, in a closed path which is equidistant from said second path throughout its length, said last named path being spaced from said first path by said second path, and a support for said collector areas comprising recessed surfaces between the collector areas the dimensions of which recessed surfaces determine in part the natural frequency of operation.

10. An electron discharge device structure having a grid, a plurality of spaced cathode parts, separate means supporting each cathode part on said grid support in insulated relation therewith, each of said means being adjustable wherebythe spacing between'said grid and each cathode part may be adjusted.

11. An electron discharge device as recited in claim 10 wherein the grid is mounted on a periphery of said grid support, and wherein said grid support has openings therein into which the cathode parts extend.

12. A composite cathode structure comprising a plurality of active cathode surfaces separated by inactive surfaces, said inactive surfaces being joined to said active surfaces and forming cavity resonators coupled therebetween, said inactive surfaces being of substantially like dimensions determining in part the frequency at which said cavity resonators operate.

13. An electron discharge device having a plura ity of adjacent act ve cathode areas. a cavity resonator coupled between adjacent active cathode areas and a plurality of anode elements spaced from and registering with said active cathode areas, a cavity resonator coupled between adjacent anode elements and a control electrode positioned between said cathode areas and said anode elements.

14. An electron discharge device comprising a cylindrical base member, a plurality of separate electron emitting areas located around the periphery of said base member, a grid electrode on a cylindrical support located around the outer periphery of said base member, said support hav 11 mg windows therein in register with said emitting areas there being a window for each emitting area, a second cylindrical support mounted around-the periphery of said support and spaced therefrom, a plurality of electron collector electrodes mounted on the inner periphery of said second support there being a collector electrode for each emitting area, said collector areas, emitting areas and windows being in register with each other, and alternating current connections to the collector areas and emitting areas.

15. An electron discharge device, comprising a cathode having a pluralityof electron' emitting areas separated by non-emitting areas, an anode having a like number of electron collector areas separated by non-emitting areas, a grid electrode disposed between said cathode and anode, said emitting'areas and collecting areas being in register, operating circuits for said electrodes including alternating current couplers to alternate emitting areas and to alternate collecting areas trodes-and coupled to the; cathode.

.17; An'el'ectron discharge devicecomprisingat least two.electrodes,and two coaxial lines each having inner and outer members, each inner member. coupled. to a different one of said two .electrodes, saidcoaxial lines being electrically insulatedifrom eachother and forming part of an evacuated closure member in which said electrodes are enclosed.

18.. An electron discharge device, comprising a grid electrode in the surface of a cylinder, a cathode electrode in the surface of a second cylinder within said first cylinder, an anode electrode in the surface of a third cylinder enclosing said'first cylinder, a coaxial transmission line having an inner member coupled to the cathode atone end thereof and a second coaxial transmission line. having an inner member coupled to 12 the anode at the end thereof adjacent to said one end.

19. An electron discharge device, comprising a cathode electrode having a plurality of electron emitting areas separated by non-emitting areas, an anode electrode having a like number of electron collector areas separated by non-collecting areas, a grid electrode disposed between said cathode and anode, said electrodes being located in parallel surfaces, at least one of said electrodes being mounted for movement relative to the other electrodes in a direction inclined to said surfaces to change the distance-between the electrodes and thereby change their normal frequency of operation.

20. An electrondischarge device, comprising'a cathode electrode having a plurality of electron emitting areas separated by non-emitting areas,

an anode electrode having a like number of electron collector areas separated byv non-collecting areas, a grirl' electrode disposed between said cathode and anode, the active areas of said electrodes lying in telescoped coaxial truncated cone-like surfaces, one for each of said electrodes, at least one of said electrodes being mounted for movement relative to the other electrodes in a direction parallel to the axis of said cone-like surfaces to change the spacing between the electrodes.

RUSSELL R. LAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,107,520 Schade-. 1 .Feb. 8, 1938 2,108,900 Peterson Feb. 22, 1938 2,130,280 Knoll Sept. 13, 1938 2,153,728 Southworth Apr. 11, 1939 2,167,201 Dallenbach. July 25, 1939 2,167,519 Manthorne July 25, 1939 2,217,745 Hansell Oct. 15, 1940 2,295,396 George Sept. 8, 1942 2,358,542 Thompson Sept. 19, 1944 2,423,819 Chevigny July 8, 1947 2,432,193 Gubin Dec. 9, 1947 2,437,279 Spencer Mar. 9, 1948 2,451,987 Sloan Oct. 19, 1948 FOREIGN PATENTS Number Country Date 588,185 Great Britain May 16, 1947