US2402612A

US2402612A - Electron discharge device

Info

Publication number: US2402612A
Application number: US424245A
Authority: US
Inventors: Sven H Dodington
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC; Federal Telephone and Radio Corp
Priority date: 1941-12-24
Filing date: 1941-12-24
Publication date: 1946-06-25
Anticipated expiration: 1963-06-25

Description

J 1946- s. H. DODINGTON ELECTRON DISCHARGE DEVICE Filed Dec. 24, 1941 INVENTOR. VE/V/i JQD/IVGTOA/ 'AITQRNEK Patented June 25, 1946 ELECT-RON DISCHARGE DEVICE Sven H. Dodington, Forest Hills, N. Y., assignor to Federal Telephone and Radio a corporation of Delaware Corporation,

Application Decembcr 24, 1941, Serial No. 424,245

11 Claims. (Cl. 250-27.'5)

This invention relates to .highfrequency electron discharge devices, and more .particularlytc suchdevices of the kind which are mounted between two lengths of concentric transmission line.

.An object of the invention is the, provision of a .high irequency multi-grid electron discharge device which, while simple in construction and stable in operation, results in a substantial gain per stage over a considerable bandwidth.

Further objects of the invention are the reductionor substantial elimination of lead inductan'ce insofar as the high frequency circuits are concerned, and the substantially complete isolation of plate and grid circuits without resort to external bypass condensers.

According to the invention, an annular cathode is provided which is secured to or integral with an annular mounting vdisc, the periphery of which is sealed between two portions 01 the glass envelope and projects beyond its outer wall. The projecting edge of the mounting disc is secured between the abutting ends of the outer tubular conductors of twojs'ect'ions of concentric transmission line which respectively form part of the grid and plate circuits. The plate electrode is mounted upon a copper sleeve which is connected by a seal to a reentrant portion of the glass envelope, through which sleeve the central conductcr of the plate section of transmission line extends to make direct contact with the plate electrode. In the embodiment described the device is construc'ted'as apentode, the control grid being connected to the inner conductor of the grid section of transmission line and the screengrid to the cathode mounting disc over a bypass condenser located inside .the envelope. The suppressor grid is connected directly to the cathode mounting disc inside the envelope,

In the drawing which accompanies and forms part of this specification:

(Fig. 1 is a longitudinal cross-section of a device constructed accordingto the invention; and

'2' is apartial, enlarged cross-sectional view of a detail of construction.

The cathode C consists of an annular channelled ring which is integral with or bonded to al'arge disc D, for example oi copper, fused between two sections of the glass envelope '3. The periphery of the discD extends beyond the glass envelope B and is welded .or otherwise secured between flanges F-on the outer tubes T, T1 of the concentric line sections. "The disc 11) thus constitutes the earth return of the concentric line sections and is therefore a part of both grid and plate circuits, but its reactance even at relatively high frequencies will not be excessive. The cathode heater H is located in the channel at the rear of the cathode, one end being connected to the disc D and the other end to a supply lead F which is brought out through the glass envelope B and the tube T as close to the disc D as possible.

The plate electrode P, which comprises a thick disc locatedin a plane parallel to that of the cathode disc D, is welded to a copper tube or sleeve J which is joined to a reentrant portion of the glass envelope B through a copper-to-glass seal. The end central conductor L2 of the plate circuit transmission line section extends into the tube J and is in direct contact with the plate P.

Between the cathode C and plate P there are mounted in any suitable manner and in parallel planes transverse to the axis of the structure, a control grid CG, a screen grid SG and a suppressor grid SP. A lead =GL for the control grid CG extends through the central aperture in the cathode and is brought out through the envelope and is connected to the central conductor L1 of the grid circuit transmission line section/As is more clearly shown in conj un-ction with Fig. 2, the screen grid SG is connected to an annular plate or ring R which is separated from the oathode disc Dby a layer-or dielectric I so as to constitute a bypass condenser BP :for the screen grid. The supply lead S forthe screen grid passes through the outer tube T1 of the plate transmission line section as close to the cathode disc D as possible. The suppressor grid SP is tied directly to the cathode disc D atone or more points inside the envelope. As the majority of the plate capacity is to the suppressor grid, this ensures that the circulating alternating plate current will flow through a minimum impedance common to the grid and plate circuits.

Although one embodiment of the invention has been shown and described for the purpose of illustration, it will be understood that modifications and alterations occurring to those skilled in the art may bemade without departing from the scope of the invention as defined in the appended claims.

What I claim is: g

1. An electron discharge device for the amplification of high frequency waves comprising a first section of concentric transmission line, a second section of concentric transmission line, a glass envelope, an annular cathode connected to an annular disc which is sealed between two portions ofrsaid glass envelope and projects beyond the outer wall of said envelope, an anode, a control grid, a screen grid and a suppressor grid grid and anode electrodes being disposed within said envelope, means securing the projecting edge of said annular disc between abutting ends of the outer tubular conductors of the first and second sections of transmission line, a galvanic connection inside the envelope from said suppressor grid,

to said annular disc, a conductor leadextending from said control grid through one end of said envelope to the central conductor of said first section of transmission line, and a direct con;-

nection between said anode and the end of the central conductor of said second section of transmission line.

2. An electron discharge device according to,

claim 1 wherein a by-pass condenser for said screen grid is provided within said glassenvelope. 3. An electron discharge device comprising 'a glass envelope, an annular metallic disk, an an nular cathode connected to said disk which is sealed between two portions of said glass envelope, an anode disposed in a plane parallel to the plane of-said cathode, first and second grid electrodes disposed between said cathode and said anode, said cathode, grid and" anode electrodes being disposed within said envelope, a metallic plate inside said envelope adjacent said metallic disk and separated from it bya layer of dielectric, and a conductive connectionextending from said second grid; electrode to said metallic plate. a 4

4. An electron discharge device comprising a glass envelope, an annular metallic disk, an annular cathode connectedto said-disk which is sealed between two portions'of saidglass envelope, an anode disposed ina plane parallel to the plane of said cathode, three grid'electrodes disposed betweensaid cathode and said anode in planes parallel to'the plane of said cathode, said cathode, grid and anode electrodes being disposed within said envelope, and a direct conductive connection within said glass envelopeextending between said annular metallic disk and the grid electrode-nearest the anode.

5. An electron discharge device comprising'a glass envelope, an annular metallic disk, an annular cathode connected to said'disk which is I sealed between twoportions of said glass envelope and projects beyond theouter wall of said envelope, an anode disposed in a. plane parallel to the plane of said cathoda. a grid electrode disposed-between said cathode and said anode, said Cathodagrid and anode electrodes being disposed within saidenvelope, a first section of concentric. transmission line, a second section of concentric-transmission line, means 7 i securing the projectingedge of said metallic disk between abutting ends of the outer tubular conductors of the first and second sections of concentric transmission line, a conductiveleadcon- Y nected to said grid electrode and extending through the central aperture of. said cathode and through the glass envelope to'the central conduct'orof said first section ,oi transmission line, and a'conductive connection between said anode velope, said central conductor of said second section of transmission line extending into said tube and being in direct electrical contact with said anode, a second grid electrode disposed between ,the first grid electrode and said anode, a metallic plate inside said envelope adjacent said metallic disk and separated from it by a layer of dielectric, and a conductive connection extending from saidsecond grid electrode to said metallic plate.

8. An electron discharge device according to claim 5, further comprising a metal tube, wherein said anode is secured to said metal tube which is sealed to a re-entrant portionof said glass envelope, said central conductor of said second section of transmission line extending into said tube and being in direct electrical contact with said anode, a second grid electrode and a third grid electrode disposed between the first grid electrode and said anode atcdifferent distances from said cathode, and a direct conductive connection within said glass envelope extending between said annular, metallic disk and the grid electrode nearest the anode. l

9, The combination according to claim 1', in combination with a metal ring parallel to and spaced fromsaid disk, a dielectric layer intermediate said disk and ring, ,Wherebythe latter form a condenser between them, and means electrically interconnecting said screen grid ,to said metalring.

, 10.Aneelectron discharge device comprising a glass envelope, a metallic disk extending across and sealed between two portions of said envelope, a cathode having, a plane electron emitting sur-, face, supported by said disk within said envelope, an anode havingra plane surface, means supporting said anode within said envelope with its plane surface parallel to and spaced from the plane surface of the cathode, first and second grid electrodes, means supporting said grid.elec-,-

trodes intermediate said cathode and anode, a

and the central conductor ofsaid second section I of transmission line. i a I 6. An electron discharge device according to claim 5, further comprising a metal tube, wherein said anode is secured to said metal tube which metallic ring in said envelope spaced from and parallel to said metallic disk, :a layer of dielectric material intermediate said "metallic ring and said metallic disk wherebys said ring and disk form a condenser within the envelope, and means electrically interconnecting said second grid with said metallic ring. 1

11. An electron discharge device comprising a glass envelope, a metallic disk extending across.

and sealed between twoportions of said envelope, a cathode having a plane. electron emittingsurface, supported by said disk within saidenvelope, an anode having a plane surface, means supporting said anode within said envelope with its plane surface parallel to and spaced from the plane surface of the cathode, three grid electrodeslongitudinally spaced from one another and positioned intermediate said cathode and anode, and means within said envelope electrically interconnecting that grid electrodenearest the anode with said metallic disk.

. SVEN H. DODINGTON.