US2592408A - Electron discharge device - Google Patents

Description

2 SHEETS-SHEET 1 IN VEN TOR. WARREN R. FERRIS BY m42' 662W irfE/YFV April 8, 1952 w. R. FERRls ELECTRON DISCHARGE DEVICE Filed April 18, 1945 April 8, 1952 w. R. FERRIS;l

ELECTRON DISCHARGE DEVICE 2 SHEETS-SHEET 2 Filed April 18, 1945 /fll /Zryn I0.

` INVENTOR. WARREN R. FERRIS Patented pr. 8, 1952 ELECTRON DISCHARGE DEVICE Warren R. Ferris, Kingston, N. J., assigner to Radio Corporation of America, a corporation of Delaware Application April 18, 1945, Serial No. 588,956

(Cl. S- 39) 9 Claims. 1

My invention relates to'electron discharge devices useful at ultra high frequencies and more particularly to magnetrons capable of operation in the frequency range from 300 to 10,000 megacycles.

Magnetrons are commonly made with an even number of anode segments surrounding a central space at the axis of which is placed a cathode or into which space electrons are directed, alternate anode segments bearing radio frequency voltages phased alternately positive and negative with respect to ground. These radio frequency voltages may be quite high, often suiiiciently so to destroy mica or other insulators used as electrode supports. The interelectrode capacity of the cathode and anode assembly is always considerable and if the electrodes are attached to a pair of small lead-in Wires which are used as transmission wires, the result will be to substantially shorten the quarter wavelength of the transmission line which these Wires usually comprise. At moderate frequencies this is not important, but in the neighborhood of 3000 megacycles the voltage node may occur so close to the anode segments that the segments operating in phase and expected to have equal radio frequency voltages on them do not do so and those remote from the node in the lead-in wires may have perhaps twice the voltage of those nearer. At still higher frequencies there might be a complete reversal of phase between plates expected to be in phase.

It is, therefore, a principal object of my invention to `provide an improved type of magnetron of the type described above.

Another object of my invention is to provide such a device which may have anodeelements supported by leadsbut in which the voltage node during operation of the device is spaced from the anode segments so that alternate anode segments are in proper phase relationship and the radio frequency voltages on the anode segments are equal. I

, A further object of my invention is to provide 7such'a device in which the anode-cathode capacity effect in shortening the effective quarter wavelength of the lead-in wire system is minimized.

. A sti11 further object of my invention is to provide such a device in which the breakdown of insulating supports is avoided.

Another object of my invention is to provide such a device capable of large power outputs and one which will operate at low voltages with low magnetic iield strengths,

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure 1 is a plan view of one form of an electron discharge device made according to my invention, Figure 2 is a right end view of Figure 1, Figure 3 is a view of the reverse side of Figure 1, Figures 4, 5 and 6 correspond to Figures 1, 2 and 3 of a modiiication of an electron discharge device made according to my invention, Figures '7, 8 and 9 correspond to Figures 1 to 3 of a still further modification of an electron discharge device made according to my invention, and Figure 10 is an enlarged section taken along the line Ill-l0 of Figure 7.

As shown in Figures l, 2 and 3, an electron discharge device made according to my invention includes the usual evacuated envelope I0 in which is mounted an indirectly heated cathode I I provided with the cathode heater wires I2-I3. Surrounding the cathode are a plurality of anode segments, such as I4 and l5, extending transversely of and supported adjacent the ends of and on two iiat elongated plate-like leadsor members I6 and I1, which form a low impedance parallel wire system, alternate anode segments being supported by oppositely disposed members I6 and I1. Anodes It, for example, are supported by the member i6 and the anode elements I5 by the member Il. Lead and support Wires 2I and 22 comprise cathode-heater leads and help support the mount within the envelope. A bead system 2 3 and 24 supports the cross members 25 and 25', which are welded to the members IB and II. Leads I9 are connected to the member I0 and leads 20 to the member I'I. In Figure 3 is shown the cathode lead 29, the ends of the members I6 and Il being maintained in spaced relation by means of the bead I8. The magnetic field is provided by means of the magnets, the poles I0', I 'l' of which are shown in Figure 2.

The conducting members I0, il provide a transmission line system having a relatively low impedance characteristic so that the anodecathode capacity has only a smalleifect on the position of the voltage node with respect to the anode elements. The voltage node on the conducting members I and Il' appears at some distance from the anode elements and the seal through the glass envelope i0 is best made at the same or another voltage node spaced a half wavelength from the node adjacent the anode segments. In a generator a voltage loop or maximum will occur at the anode segments, hence the seal through the envelope should be spaced from the anode segments a distance substantially equal to one or larger odd number of quarter wavelengths. Thus voltage breakdown is avoided at the supporting insulator. The beads I8, 23 and 24 are also placed at voltage nodes to prevent voltage breakdown. 'Ihe points at which the leads leave the envelope run c-ool and are not subject to stray electron bombardment so that the danger of voltage breakdown is still further removed. Likewise as a result of the node being some distance from the anode segments. the anode segments will be in proper phase and will have substantially the same voltage differential at all times. In actual construction silver solder or rivets are usually used to attach the anode segments to the flat conducting members or strips I6 and il constituting the lead-in pair, although one-piece construction could be obtained by stamping, casting or machining the entire half of the assembly from one piece of metal. I prefer to use copper or some non-magnetic material and six or eight anode segments although any even number of segments could be used. Tubes of this construction have produced three watts of continuous radio frequency power at an anode voltage less than 500 and an efiiciency of 25%. The ilat envelope permits the magnet poles to be placed close to the ends of the anode segments.

In Figures 4 and 6, inclusive, is shown a modiication of the device shown in Figures 1 to 3. In this arrangement the anode segments 32 and 33 are spaced a half Wavelength from the inner ends of the iiat conducting members 32-33 which extend through the end of the envelope I0. The conductors 32-33 support the anode segments around a space in which is mounted the indirectly heated cathode Il. Cathode-heater leads 3U and 3l are secured to leads 38 and 33. There are provided the bead and rod constructions 34, 36 and 31 for supports for the cathode and for maintaining the conductors 32 and 33 properly spaced and for providing a support for the cathode lead 4| attached to the bar 48, the cathode-heater leads 30 and 3l being supported from the beads Sli- 31. Magnets 32 and 33 providethe usual magnetic eld. The sea-l through the envelope is madeat a voltage node, as inFigs. 1-3. The half wavelength portions of the conductors 32-33 provide an open-ended resonator tuned to the operating frequency of the device.

In Figures '7 to 9 I show a still further modification of an electron discharge device made according to my invention. In this arrangement I provide a pair of at ribbon-like conductors 49 and =50, which support respectively anode elements 5l and anode elements 52, the indirectly heated cathode 48 being positioned within the space surrounded by these anode elements. The cathode lead 54 extends between the press 41 of the envelope 45, having base 46. and the cathode supporting conductor 53'. The ribbon- like conductors 49 and 58 are maintained in spaced relationship by means of beads 53 and two pairs of cross bars 6I, 62 and 6l' and 82 electrically connected and soldered to the conductors. Cathode-heater leads 55 and 58 furnish current for heating the cathode heater. Conducting strapsl 5l and l58 are electrically connected to the lower 4 cross bars 62 and 62' for the purpose of and can be used as a pair of Lecher wires for obtaining ne tuning of the system, the other conductors being used to take the energy out of the system. Thus the far and near ends of the conductor members 49 and 5U are connected by conductors l5I', 58', 59 and 68 to extend through the envelope.

The specific arrangement of the anode elements is disclosed in Figure 10. Anode elements 5'2 are electrically connected and soldered to the flat conductor 5D Whereas the anode electrodes 5l are electrically connected and soldered to a conductor 49. These elements extend through the conductors and transversely of the conductors, alternate anode segments during operation of the device being out of phase.

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:

l. An electron discharge device having a pair of elongated flat spaced oppositely disposed conducting members, said conducting members having registering apertures therein. a plurality of parallel conductors extending through and spaced around said apertures and mounted intermediate their ends transversely of and on said conducting members and providing anode segments, alternate conductors being connected to opposite conducting members, cathode means adjacent said parallel conductors for providing an electron discharge within the space surrounded by said conductors, and means adjacent said conductors for providing a magnetic field within the space surrounded by said conductors and parallel to said conductors.

2. An electron discharge device having a pair of elongated iiat spaced oppositely disposed conducting members, said conducting members having registering apertures therein, a plurality of parallel conductors spaced around said apertures and mounted intermediate their ends transversely of and on said conducting members and providing anode segments, alternate conductors beingconneeted to opposite conducting members, and cathode means adjacent said parallel 'conductors for providing an electron discharge within the space surrounded by said conductors, each of said conductors extending through and beyond the conducting members.

3. An electron discharge device having an envelope, a pair of elongated spaced flat 'conducting strips oppositely disposed and lyin'gin parallel planes Within said envelope, said conducting strips having registering apertures therein, a plurality of parallel conductors extending through and spaced around said apertures and mounted intermediate their ends transversely of and on said conducting strips and providing anode segments, alternate conductors beingconnected to opposite conducting strips, cathode means adjacent said parallel conductors for providing an electron discharge within the space surrounded by said conductors, conducting leads extending from the endpcf said strips within the envelope through said envelope, and means adjacent said conductors for providing a magnetic ileld within the space surrounded by the anode segments and parallel to said anode segments.

4. An electron discharge device having an envelope, a pair of flat oppositely disposed conducting members extending through and into said envelope and sealed therethrough and lying in parallel planes and spaced from each other, said conducting members vhaving registering apertures therein, a plurality of parallel conductors extending through and spaced around said apertures and mounted intermediate their ends transversely of and on said members and providing anode segments, alternate segments being supported by a, different member, said apertures being intermediate the ends of said conducting members within the envelope and the portion of said conducting members sealed through said envelope, a cathode adjacent said parallel conductors for providing electrons within the space surrounded by said anode segments, and means adjacent said conductors for providing a magnetic eld within said space and parallel to said anode segments.

5. An electron device designed tc operate Vat a predetermined frequency comprising an envelope of insulating material, a pair of elongated flat spaced oppositely-disposed conducting Vmembers within said envelope and having leadsfsealed ythrough the wall of said envelope, said members having registering apertures therein, a plurality of parallel anode conductors spaced around said apertures and mounted transversely of and on said conducting members, alternate conductors being connected to opposite conducting members, and cathode means adjacent said parallel conductors for providing an electron discharge within the space surrounded by said conductors, said apertures being spaced from the lead seals in the envelope wall a distance substantially equal to an odd number of quarter wave lengths at said predetermined frequency.

6. An electron discharge device designed to operate at a predetermined frequency comprising an envelope of insulating material, a pair of elongated flat spaced oppositely-disposed conducting members within said envelope and having leads sealed through the wall of said envelope. said members having registering apertures therein, a plurality of parallel anode conductors spaced around said apertures and mounted transversely of and on said conducting members, alternate conductors being connected to opposite conducting members, and cathode operate at a predetermined frequency comprising an envelope of insulating material, a pair of elongated ilat spaced oppositely-disposed conlil ducting members Within said envelope and A being connected to opposite conducting members, and cathode means adjacent said parallel conductors for providing an electron discharge within the space surrounded by said conductors, said apertures being spaced from the conducting member seals in the envelope wall a distance substantially equal to an odd number of quarter wavelengths at said predetermined frequency.

8. An electron discharge device designed to operate at a predetermined frequency comprising an envelope of insulating material, a pair of elongated flat spaced oppositely-disposed conducting members within said envelope and having leads sealedthrough the wall of said enve lope, said members having registering apertures therein, a plurality of parallel anode conductors spaced around said apertures and mounted transversely of and on said conducting members, alternate conductors being connected to opposite conducting members, and cathode means adjacent said vparallel conductors for providing an electron discharge within the space surrounded by said conductors, said apertures being spaced from the lead seals in the envelope wall a. distance substantially equal to an odd number of quarter wavelengths at said predetermined frequency, said conducting members extending inwardly beyond said apertures a distance substantially equal to a half wavelength at said predetermined frequency.

9. An electron discharge device designed to operate at a predetermined frequency comprising an envelope of insulating material, a pair of elongated flat spaced oppositely-disposed conducting members within said envelope and sealed through the wall thereof, said members having registering apertures therein, a plurality of parallel anode conductors spaced around said apertures and mounted transversely of and on said conducting members, alternate conductors being connected to opposite conducting members, and cathode means adjacent said parallel conductors for providing an electron discharge within the space surrounded by said conductors, said apertures being spaced from the conducting member seals in the envelope wall a distance substantially equal to an odd number of quarter wavelengths at said predetermined frequency, said conducting members extending inwardly beyond said apertures a distance substantially equal to a half wavelength at said predetermined frequency.

WARREN R. FRRIS.

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

UNITED STATES PATENTS Number Name Date 1,750,386 Brown Mar. l1, 1930 1,981,058 Marconi et al Nov. 20, 1934 2,020,310 Gunn Nov. 12, 1935 2,128,237 Dallenbach Aug. 30, 1938 2,144,222 Hollmann Jan. 17, 1939 2,147,159 Gutton et al Feb. 14, 1939 2,209,923 Kilgore July 30, 1940 2,247,077 Blewett et al June 24, 1941 FOREIGN PATENTS Number Country Date 445,084 Great Britain Apr. 2, 1936 522,905 Great Britain July 1, 1940

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