US2433044A

US2433044A - Electron discharge device

Info

Publication number: US2433044A
Application number: US440297A
Authority: US
Inventors: Andrew V Haeff
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1942-04-24
Filing date: 1942-04-24
Publication date: 1947-12-23
Anticipated expiration: 1964-12-23

Description

Dec. 23, 1947. A. v. HAEFF 2,433,044

ELECTRON DI S CHARGE DEV I CE Filed April 24, 1942 s Sheets-Sheet 1 INVENTOR Dec. 23', 1947. I v, HAEFF 2,433,044

ELECTRON DISCHARGE DEVICE Filed April 24, 1942 3 Sheets-Sheet 2 vvvvv vI INVENTOR ATTORNEY Dec. 23, 1947.

A: V. HAEFF ELECTRON DI S CHARGE DEVI CE Filed April 24, 1942 I5 Sheets-Sheet 3 un a- *1 l ENTOR a2 W a C v ATTORNEY Patented Dec. 23, 1947 Andrew V. Hae f', 1Witshington, D Cl, assignor to Radio Corporation of America,- a corporationof' Delaware Application Apical; 1942, serial na 440,291 1 7 Claims. (01. 2511 2 755) v My invention relates to electron discharge de-' vices; more particularly to such devices utilizing electron beam deflection anduseful atultra high frequencies.

In conventional-tubes utilizing beam deflection', a'be'amof electrons is directed from the cathode 'betweena pair: of deflecting electrodes towardan apertured electrode behind which is placed an electron collector. Alternating radio frequencyvoltagesare appliedto' the deflecting electrodes to cause the electronbeam to 'be defiected'a-eross the" apertured electrode, thus to control-the amount of currenttothe collector, which may be used as an output electrode. In such types of tubes the deflection 's'ensitivity' drops off as the -freduency at which the tube is operated is increased; that is the transco-nductance of the tube decreases. Tubes ofthis kind are also subject to the'limitation of the usual conventional tubes in that when operated at ultrahigh frequenciesthe presence of considerable loadingin the input circuit results in an excessive amountof power being required to drive the tube. This decreasesthe effective power gain'of the tub when operated as-an amplifier.

Fundamental causes of high input loading are,

among'otherthings. ohmic andradiation losses due tohigh Circulating currents'in electrodes and leads; Electron loading also results from the in teraction of the electron stream and the circuits connected to tube electrodes, and may include degenerative or regenerative effectscaused by com-' mon lead impedances.

It is an object oimy invention'to provide an electron. discharge device of the beam deflection type which is-particularl-ysuitable for use at'high frequencies and which has a comparatively high transconductance.

Itis another objectof my invention to providesuch a device'utilizing an input circuit in which input-loading: is minimized, thus making more effective use of the driving power.

A still further object of my inventionis to provide an electron discharge device of the beam deflection type useful at ultra high frequencies and which employs low loss input and output electrode systems and circuits.

A=iu-rther object of my invention is to provide such 'a" device in which undesired coupling; due to common leads and ineffective shielding, is reduced to a minimum.

Another object of my invention is to provide an electron discharge device of the beam deflection type useful at ultra highfrequen'cies as an amplifier, oscillator 01" a mixer;

2" The novel features-which I- believe to be Chal?- acteristic' of myinventionare set forth with particularity'in the appendedclaims; but the invention itself will-best be understoodby reference to the following description taken inconnection with the accompanying drawing in which Figure 1 is; a schematic 1 longitudinal section of an electron discharge device made accordingto my invention its associated-circuit, Figure 2 is a perspective," partly irrsection, of the electrode system utilizedin'i thedeviceshown-in Figure 1, Figure 3 is a schematic longitudinalsection of a modifi cation of am electron discharge device made according-to my invention and its associated circuit; Figure 4 is a-perspective, partly section, ofthe output tank circuit utilized in the electron dischargedevice shown inFigure 3,'-Figures 5, 6- and-v are schematic longitudinal sections ofother modifications of my invention.

As showninFigure 1, an electron discharge device'ma'de according to my invention comprises an envelope l0 having at, one end a cathode l I,

which may be indirectlyheated', andra pair of ac celeratingandfocusing: electrodes I 2'- l 3-, and at the other end acollector- 14' for receiving electrons. In accordance with myinvention, 1 position' between the focusing electrode andthe collectora resonant cavitytank' circuit or resonator I5 havingapai r of oppositely disposed deflecting elementsl-fi -llpositioned adjacent to and electrically connected to and supported by opposite walls ofthecavity adjacent theapertures 2Ban d;

21. Positioned between the resonant cavity and the collector is-the conducting plateflike member l8- having? anelongated aperture 19 and centrally--positionedaconducting: rod- 20 for thuspro vid-ing a= double aperture. Preferably the length of the overlapping portions ofthe deflecting elementslfi and H is equal tothe distance travelled by an electron 'du-ring a half period of the appliedcontrollin g voltage while the tube isin oper ation: Ithas been found that this provides maximum deflection-sensitivity, V

A;; biasing voltage divider arrangement for the deflecting-electrodes is shown at 2 l and the output is; taken between collector Hand apertured conducting member {8 by means of'the output transformer 24. Voltage sources for'the various electrodes are shown at. The input coupling loop 22 within the resonator I5 is connectedto a coaxial transmission line 23.

In operationthe biasing or polarizing voltages are appliedto electrodes l'2l3 to focus and properly direct electrons through the elongated aperture 'of the resonantcavity tank circuit l5.

In passing through the resonant cavity the beam is subjected to a transverse alternating field between the elements I9 and I1 and deflected across apertured element I8, the electrons being collected at I4, the double aperture in element I8 giving a desired control voltage-anode current characteristic.

The resonator is maintained energized by means of the input line 23 and coupling loop 22. In one mode of excitation an electromagnetic field is set up within the cavity such that the magnetic lines of force are approximately concentric with and coaxial with the cavity. The radio frequency currents circulate alternately from one side of the inner surface of the cavity to the other between the apertures, causing each of the deflecting elements I6 and H to receive a voltage thereon approximately equal to the voltage appearing at the aperture adjacent which the element is connected, so that the electron stream is subjected to a deflecting electric field.

In the modification shown in Figure 3 which utilizes a push-pull output resonator, the input circuit is substantially the same as that shown in Figure 1. Mounted at one end of the envelope of which the resonators form part is an elongated cup-shaped insulation member 29 enclosing cathode 39, accelerating or modulating grid 3|, and focusing and accelerating

electrodes

32 and 33, the cup-shaped member being fused to the collar 4| of the resonant cavity tank circuit 38. The resonant cavity tank circuit is energized by means of coupling loop 42 so that a deflecting voltage appears across

electrodes

39 and 49 as explained above. FOllOWiIlg this resonant cavity 38 is a beam-directing and separating electrode system housed within the insulating collar portion 44 fused to the collar 43 of resonator 38 and collar 51 of resonator 48. Electrode 4'! maintained at a lower potential than the accelerating and directing

electrodes

45 and 46 insures that the beam is directed into one or the other of the two passageways provided in the resonant cavity 48. The resonant cavity 48 is provided with reentrant tubular extensions 49 and 59 separated by gap and 52 and '53 separated by gap 54, the output being taken by means of coupling loops 55 and 59. A collar 58 supports a collector system comprising cup-shaped members 3435 having mounted therein

secondary electron suppressors

36 and 37, the envelope being sealed by means of the plate 59, supporting

members

34 and 35.

The modulating circuit II may be utilized to modulate the stream before entrance of the beam into the deflecting resonator or it may be utilized simply as an accelerator. The biasin voltage and divider source is shown at 69 for biasing and focusing

electrode elements

32 and 33. As in the first case the beam of electrons is deflected in passing between

electrodes

39 and 49 so as to pass between

electrodes

41 and 46, or 45 and 41, and in passing across either of the gaps 5| or 54 excites the resonant cavity 48. In the mode of oscillation utilized, each half of the resonator oscillates at a phase difierential of 180 with respect to the other half so that the beam will always be decelerated in passing over gap 5| or gap 54 to maintain the resonator energized. This results in a push-pull output which can be extracted by means of the coupling loops 55 and 56. The manner in which the resonator 48 is caused to be energized by inductive action is now well understood and is described in my earlier Patent 2,237,878, issued April 8, 1941.

In the modification shown in Figure 5 I utilize a double cavity for successively extracting energy from the beam passing through this cavity. The insulating cup-shaped member 89 contains cathode GI and grid 82, as well as the focusing and accelerating

electrodes

83 and 84. The electron beam again passes through the deflectin resonant cavity tank circuit 85 driven by coupling loop 88 and having deflecting electrodes 96 and 8'! through which the beam is directed and by which the beam is deflected. The beam is directed either between electrodes 90 and 92 or 9| and 92 positioned within the collar member 89. Electrodes 98 and 9| act with the electrode 92, which is the separating electrode held at a potential lower than electrodes 99 and 9|, to direct the beam through one or the other of the two paths through the output resonant cavity tank system 98. This system comprises a pair of

cavities

94 and 95 having reentrant portions 96, 91, I94 and I95 and having a separating chamber formed by partitions I99, IOI having passageways I99 and I9I extending therethrough. The resonant cavities are energized when the beam passes gaps 98 and I02 and 99 and I93. Energy is extracted from the resonant

cavity tank circuits

94 and 95 by means of coupling loops I01 and I89 and the electrons collected by means of the cup-shaped member I99. The modulating circuit is shown at I 91 for the grid, and the voltage divider and voltage source I 98 is provided for accelerating

electrodes

83 and 84. A voltage source I 99 provides the necessary voltages for other electrodes and the voltage divider system II9 permits adjustment of the voltage on the beam directing electrodes 99, 9| to properly insure that the beam will travel through the proper passageway. Cavities 9495 are separate and distinct and separated by the apertured partitions I99 and I9I, the transit time of the electrons being matched to the output system such that the electrons are subjected to a decelerating field at gaps 98 and I92, and 99 and I03 in passing through the output system. This requires that the transit time of the electrons through elements I99 and IOI be equal to approximately one-half period, assuming that resonant

cavity tank circuits

94 and 95 are operating out of phase. Of course this arrangement need not be used and the electron transit time through I99 and I9I can be made more or less if a different phase relationship is desired between the voltages induced in

cavities

94 and 95. The mode of oscillation for each of the

cavities

94 and 95 is the same as for cavity 48 in Figure 3.

In the modification shown in Figure 6 I employ a push-pull system in the output utilizing a Lecher wire arrangement and a double anode or collector system. In this arrangement envelope III has at one end cathode II2, accelerating grid H3 and accelerating and focusing electrodes H4 and H4, the resonant cavity II 5 being driven by coupling loop II8, which is provided with deflecting electrodes H6 and Ill. Electrons are directed into the shielded output system comprising anode electrodes I29 and I2I connected together by Lecher wire system I I9, the separating electrode I24 being maintained at a lower potential than electrodes I29 and I2I and Lecher wire system I I9. This whole arrangement is shielded by means of shielding compartment I22 and energy inductively extracted by means of coupling loop I25. The voltage sources for properly biasing or polarizing are shown at I 26, I27 and I28. Since electrodes I 20 and I2I operate 180 out of phase, the deflection of the electron beam from one to the other of these two electrodes can be properly phased to drive the output system.

In Figure 7 I show a still further modification of my invention utilizing a doubly decelerating output circuit mounted within a cavity. Here envelope I36 has mounted at one end cathode ItI, accelerating electrode I32 and accelerating and focusing electrodes I33 and I34. The

resonant cavity I35 driven by coupling loop I38 is provided with deflecting electrodes I35 and I3! for bringing about a deflection of the beam generated by the cathode electrode system.

The output system comprises the enclosed conducting structure Itt provided with reentrant portions I42, I i-1, I43 and lit, which with the tubular electrodes MI] and MI provide a double set of gaps I45 and I46, and I48 and I50, the separating electrode I63 extending through the bottom of the envelope and being maintained at a lower potential than the conducting enclosure and the elements within the enclosure. The beam in passing, for example, through the tubular member Mil to the collector IEI is subjected to a double deceleration, giving up energy at gaps I45 and I56 in a manner now well known and in accordance with the principles set forth in my patent above referred to. Since the tubular elements Iii] and I4I extract energy from the stream 180 out of phase with each other, they may be properly coupled by means of loop I64, which in turn is coupled to output loop I55 extending through envelope I35] and within enclosed conducting member I39. Thus this latter arrangement provides a push-pull double decelerating device in combination with a resonant cavity circuit system for deflecting the electron beam.

In all arrangements above described the input circuit which comprises the resonant cavity tank circuit or resonator is a circuit of low loss both from the standpoint of resistance and radiation losses. Loss of deflection sensitivity due to design of the deflecting electrodes is at a minimum and the output and input circuits because of the enclosed fields are completely shielded from each other and because of the absence of common leads there is substantially no reaction or interaction between the input and output systems. If desired the forms shown in the figures could be utilized as well for mixers by applying a local oscillator voltage, for example, either to the grid electrodes SI and 8!, as shown in Figures 3 and 5, or both local oscillator and signal voltage could be applied to coupling loops 42 and til, for example. In either case both voltages could be utilized for bringing about intermediate frequency voltages in the output system.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims.

What I claim as new is:

1. An electron discharge device having cathode means for supplying a beam of electrons, a cavity resonator positioned adjacent said cathode means and having oppositely disposed apertures in opposite walls thereof through which the beam path lies and deflecting electrode elements within said cavity resonator and separate from but electrically connected to opposite walls of the cavity resonator and adjacent each of said apertures and having portions oppositely disposed between which said beam path lies, and an output cavity resonator in the path of said electrons and having a pair of apertures in one wall thereof for directing the beam of electrons alternately through said apertures during operation of said electron discharge device.

2. An electron discharge device having cathode means for supplying a beam of electrons, and a cavity resonator positioned adjacent said cathode means and having oppositely disposed apertures in opposite walls thereof through which the beam path lies, and deflecting electrode elements separate from but electrically connected to opposite walls of the cavity resonator and adjacent each of said apertures and having portions oppositely disposed between which said beam path lies, and an output cavity resonator in the path of said electrons and having a pair of apertures in one wall thereof for directing the beam of electrons alternately through said apertures during operation of said electron discharge device, and means positioned between said cavity resonators including a beam directing electrode system for assisting and directing the beam of electrons into one or the other of the apertures of the output cavity resonator.

3. An electron discharge device having cathode means for supplying a beam of electrons, and a cavity resonator positioned adjacent said cathode means and having oppositely disposed apertures in opposite walls thereof through which the beam path lies, and deflecting electrode elements separate from but electrically connected to opposite inner walls of the cavity resonator and adjacent each of said apertures and having portions oppositely disposed between which said beam path lies, and an output cavity resonator having a pair of apertures in one wall thereof, the beam of electrons being directed alternately through said apertures during operation of said electron discharge device, and an electrode system positioned between said cavity resonators comprising a pair of accelerating and directing electrodes oppositely disposed, and another electrode between said oppositely disposed electrodes for separating the electron beam during operation of the electron discharge device.

4. An electron discharge device having cathode means for supplying a beam of electrons, a cavity resonator positioned adjacent said cathode means and having oppositely disposed apertures in opposite walls thereof through which the beam path lies, and deflecting elements separate and distinct from but electrically connected to opposite walls of the cavity resonator and adjacent each of said apertures and having portions oppositely disposed between which said beam path lies, and an output cavity resonator having a pair of apertures in one wall thereof for receiving the beam of electrons alternately through said apertures during operation of said electron discharge device, said output cavity resonator having reentrant portions extending toward each other but separated by a gap across which the electron beam is to be directed.

5. An electron discharge device having cathode means for supplying a beam of electrons, and a collector means forming an electron path therebetween, and a cavity resonator positioned between said cathode means and said collector means and having oppositely disposed apertures in opposite walls thereof through which the beam path lies, and deflecting electrode elements electrically connected to opposite walls of the cavity resonator and adjacent each of said apertures and having portions oppositely disposed between which said beam path lies, and an output cavity resonator having a plurality of pairs of oppositely disposed apertures in opposite walls thereof for directing the beam of electrons alternately through different pairs of said apertures during operation of said electron discharge device, said collector means including a cup-shaped member, and means positioned within said cup-shaped member for suppressing secondary electrons.

6. An electron discharge device including a cathode means for providing a beam of electrons, and collector electrode means forming an electron path therebetween, a cavity resonator positioned adjacent said cathode means and having a pair of oppositely disposed apertures in opposite walls through which the beam path lies, a pair of deflecting electrodes within the cavity resonator positioned adjacent said apertures and between which said beam path lies, collars on opposite outside walls of said cavity resonator surrounding said apertures, and a cup-shaped member enclosing said cathode means sealed to one of said collars, a second cavity resonator provided with a collar, and an insulating tubular member sealed between said last collar and the other collar on said first cavity resonator, and a beam directing and separating system within said tubular member, said second cavity resonator being provided with two pairs of oppositely disposed apertures through which the electron beam is to be alternately directed, and means sealing said collector electrode means to said second cavity resonator providing an evacuated chamber for said cathode means and collector electrode means.

7. An electron discharge device having cathode means for supplying a beam of electrons, a cavity resonator positioned adjacent said cathode means and having oppositely disposed apertures in opposite walls thereof through which the path of said beam of electrons is directed, and a pair of deflecting elements within the cavity resonator positioned adjacent said apertures and connected to the inner walls thereof and between which the path of said beam of electrons is directed, and an output cavity resonato system having a pair of apertures in one wall thereof, the beam of electrons being directed alternately through said apertures during operation of said electron discharge device.

ANDREW V. HAEFF.

REFERENEES CIZTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,266,428 Litton Dec. 16, 1941 2,281,935 Hansen et a1. May 5, 1942 2,329,780 Zalesak Sept. 21, 1943 2,275,480 Varian et al Mar. 10, 1942 2,275,165 Varian et al. Feb. 3, 1942 1,920,863 Hopkins, Jr. Aug. 1, 1933 2,103,507 Zworykin Dec. 28, 1937