US2452318A - Electron discharge device utilizing cavity resonators - Google Patents

Description

Get. 26, 1948. 1 s. NERGAARD ELCTRON DISCHARGE DEVICE UTILIZING CAVITY RESONATORS Filed March 27, 1944 2 Sheets-Sheet l @et 26, 1948. 1.-. s. NRGAARD 2,452,318

ELECTRON DISCHARGE DEVICE UTILIZING CAVITY RESONATORS Filed March 27, 1944 2 sheets-sheet 2 ATTORNEY Patented Oct. 26, 1948 ELECTRON DISCHARGE DEVECE UTILIZING CAVITY RESONATORS Leon S. Nergaard, Princeton, N. J., assigner to Radio Corporation Iof America, a corporation of Delaware Application March 2v, 1944, serial No. 528,195

7 Claims.

"Myinvention relates to electron` discharge devices and circuits therefor and particularly to such devicesl and circuits useful at ultra high frequencies.

The present application is directed to an im provement over the device and circuit shown in my co-pending application, Serial No. 514,206, iiled December 14, 1943, and assigned to the same assignee as the present application.

Electron discharge devices using cavity resonators are used at ultra high frequencies. In the triode type, the electrodes are usually arranged in the order of cathode, grid and anode, and may have radially directed supports and lead-ins extending through the envelope and contacting the cavity resonator circuits. For example, in the triode an input cavity resonator, which may be of the coaxial line type, is connected between the cathode and grid, and the output resonator is'connected between the grid and anode. In another type of tuberei'erredto as an inductive output tube, the electrodes are in the order of cathode, grid, accelerator and collector. The input resonator, usually ofthe coaxial line type, is connected between the cathode and grid, a second resonator is connected between the grid and accelerator and the output resonator is positioned between the accelerator and collector.` The resonator connected .between the control grid and accelerator or screen is used to bring the accelerator to cathode potential for radio frequencies and is used for regeneration to compensate for the diode loading. At ultra high frequency it is desired to so construct and arrange the leads to tube electrodes that they have as low inductance as possible, or, alternatively, to so arrange them that they comprise conductors of transmission lines which may be joined with an external circuit. Leads of triodes and of the triode section of inductive output tubes have been brought out in the same space sequence as the electrodes have within the tube, namely the sequence cathode, grid andanode, or in the case of the inductive output tube, the accelerator and collector. Because of this arrangement it is necessary to use the so-called grounded grid circuit, which is characterized by having a circuit between the grid and plate, or grid and accelerator. The disadvantages of this arrangement are, rst, the full diode loading of the tube appears across the input circuit. This requires a higher driving power and results in a low power gain. Second, in the inductive output' tube the circuit between the grid and accelerator is used to bring the accelerator to cathode potential as far as radio frequency is concerned,v or to introduce regeneration to compensate for the diode loading. Be-

cause regeneration tends to be unstable, tuning` of the circuit is critical. It is desirable to eliminate diode loading and to remove the circuit between grid and accelerator. This would simplify tuning of the tube circuit without sacricing performance.

It is, therefore, the principal object vention to provide an improved form of an elec-.- tron discharge device and circuit useful at ultra high frequencies.

It is another object of my invention to pro-`A Vide such a device utilizing cavity resonators but in which the usual diode loading associated with tubes of this type is eliminated, and in which circuits requiring critical tuning are made unnecessary.

It is a further object of my invention to pro vide such a device utilizing cavity resonator circuits in which the grounded grid circuit is avoided.

The novel features which I believe to be characteristic of my invention are set forth with particularity` in the appended claims, but the in-l vention itself will best be understood by reference to the following description taken in con nection with the accompanying drawing in which,

Figure 1 shows a longitudinal section of an electrondischarge device and circuit made ac cording to my invention, Figure 2 is an enlarged' detail section of the electrode arrangement of the device shown in Figure4 1, Figure 3 is a transversesection taken along the line E- of Figure 2 and Figure 4 is a diagram showing an equivalent circuit of the device shown in Figure 1.

' In accordance with my invention I provide an electron discharge device having an elongated indirectly heated l0, control grid assembly comprising envelope 9. containing an cathode wires l, collar lli, conductor 6B, and cone-v shaped collar member tl, accelerating electrode` of my Sine l tubular member 2| is closed at one end by the conducting member 22 and provided at the other end with an end wall 24. The device is tuned by means of the tuning short circuit 23. This input circuit is coupled between the cathode and the grid, the grid being capacitively coupled to the inner-member'ZDfinsulated from the grid ring by meansof the non-conducting collar 25, preferably of mica. The end wall 24 is provided with spring contact fingers 2B making direct electrical contact with'the cathode.

The output circuit comprises a second resonator including disc end members 30 and 3l electrically connected at their .peripheries by means of the collar 32. The end wall 3l: is provided with collar 33 having spring ngers 34 electri- 4 and a cavity resonator coupled between both said conducting means.

2. An electron discharge device having an envelope containing a cathode assembly, a hollow grid assembly and another electrode in the order named, said grid assembly including a colla-r supportingfnmeans supportedI from said envelope, said cathodelassembly beinginsulatingly supported entirely within said grid assembly and solely from said grid assembly, conducting means connected to said grid collar supporting means,

cally contacting the accelerator .conducting ring l1; the other wall 30 is capacitively coupled to the input resonator through the mica insulating A ring 35. Thus the accelerator and resonator may be maintained` at a different voltage with respect tothe input circuit. The input circuit may be maintained at ground potential since it is conn ected to the cathode.

In accordance with my invention I provide novel V.cathode andgrid supports having crossedover connections which permit the cathode and lar issupported by means of the rodl and insulating bead construction 43, which securely and firmly supports the cathode within and coaxially of the grid. Radially directedwires or conductors 4B extend between leadsV 4l] and electrically connect they cathode with the cathode ring. l5. Thus an improved type of cross-over cathode and grid lead construction is 'provided whicheliminates the objectionable features above Vmentioned of the usual electrode arrangement. .A cathode heater lead 42 extends to the exterior of the envelope through which it is sealed. The other side of the heater is electrically connected to the'-l cathode.

In Figure 4 is shown the equivalent clrcuitof the device shown in Figure 1, the numerals indicatingithe same elements as in Figure 1.

While I have indicated the preferred embodi-l.

1'. An electron discharge device having an en-V velope containing a cathode, a hollowv grid assembly and another'Y electrode, vall in order named, said grid assembly including a collar member, said cathode being insulatingly supported solely from said grid assembly and enclosed entirely within said grid assembly, conducting means connected to said collar member, conducting means connected tos'aid cathodeand-extending' through said grid l assembly but out of contact therewith,

conducting means connected to said cathode and extending through but out of contact with said grid assembly and `a cavity resonator coupled between both of said conducting means.

3. An electron discharge device having a cathode, a hollow grid assembly and another electrode in the order named, said cathode being supported within said grid assembly and coaxially of said grid assembly by means of insulating spacer4 members, radially extending conducting means connected to said cathode and extending through but out of contact with said grid assembly,I and a cavity resonator coupled between said grid assembly and -said cathode conducting means.

4. An electron discharge device havinga cathode, a hollow grid assembly and another electrode in the order named, said vgrid assembly including a conducting collar, a conducting conelike member connected to one end of said collar, said cathode being mounted axially of said collar, and insulatingly supported within said grid and collar, radially-extending conductors extending between said cone-like member and saidcollar `and connected to said cathode, and a cavity resonator vcoupled .v between said grid and said cathode, one side of said cavity resonator being electrically connected to said radially extending conductors and the other side of said cavity resonator being capacitively coupled to said conelike member. y

5. An electron discharge device having an envelope containing a cathode, a hollow grid and 'another electrode in the order named, ring-like conducting members sealed through said envelope and spaced along said envelope, said grid including a collar having a ared skirt thereon and -a oraminous portion supported thereon, said skirt. being electrically connected to one ofysaid ringilike conducting members, said cathode beinginsulatingly supported within said collar and grid, leads connected to said cathode and extending between said collar and said foraminous portion but'out of contact therewith and electrically connected to another of said ring-like conducting members, and a cavity resonator coupled between said grid and cathode ring-likel conducting members, one sidel of said cavity resonator being electrically connected to a ring-like conducting member and the other side of the cavity resonator being capacitively coupled to the other ringlike Vconducting member.

6. An electronV discharge device having-a cathi ode, a hollow grid and another electrode inthe tending between said collar andsaid foraminous portion and; collar but out` of contact therewith and electrically connected to another of said ringlike conducting members, and a cavity resonator coupled between said grid and cathode ring-like conducting members.

'7. An electron discharge device having an envelope containing a cathode, Va hollow grid and Ianother electrode in the order named, ring-like conducting members sealed through said envelope and spaced along said envelope, said grid including a collar having a flared skirt and a foraminous portion supported at one end of said collar, said skirt being electrically connected to one of said ring-like conducting members, said foraminous portion being supported on said collar by a plurality of rod-like conductors spaced around said collar, said cathode being insulatingly supported Within said grid, leads connected to said cathode extending between but out of contact with said rod-like conductors and electrically connected to another of said ring-like members,

and a cavity resonator coupled between said grid and cathode ring-like conducting members, one side of said cavity resonator being electrically connected to said cathode ring-like conducting member and the other side of .the cavity resonator being capacitively coupled to said grid ringlike conducting member.

LEON S. NERGAARD.

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

UNITED STATES PATENTS Number Name Date 2,128,232 Dallenbach Aug. 30, 1938 2,190,511 C'age Feb. 13, 1940 2,287,845 Varian et al June 30, 1942 2,353,743 McArthur July 18, 1944 Goodohld Feb. 19, 1946

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