US2481151A - Electron discharge device - Google Patents

Description

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Filed April l5, 1944 @Wm 6 E949. n. M. POWERS ELECTRON DISCHARGE DEVICE www 2 sheets-sheet 2 Filed April 1s, 1944 Patented Sept. 6, 1949 UNITED STATES ETENT OFFICE 2,481,151 ELECTRON DISCHARGE DEVICE Donald M. Powers, Boston, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application April 13, 1944, Serial No. 530,861

15 Claims. (Cl. 250-27.5)

This invention relates to a magnetron oscillaand I0 which project from the opposite ends of tor of the plural-anode cavity type which is the cathode structure. One of the conductors 9 adapted to generate oscillations of hyper-fremay be electrically connected `to the cathode quencies having wavelengths of the order of a few sleeve 8, while the other conductor lo is insulated centimeters or less. 5 from said sleeve. The cathode 5, is supported -by In devices of this kind it is desirable that the a pair of lead-n conductors ll welded respecoscillations generated be fed into a transmission tively to the end conductors 9 and Ill. The lead-in system, such as a hollow Wave guide, in a dleCt conductors Il pass through glass seals l2 mounted and efficient manner. It is therefore an object the mitm. of conducting i)mes i9, heimat of this invention to couple the energy of the oscil- 10 ically fastened through the Wan o'f the envelope lating portions of such a magnetron into a hollow 1 adjacent the opper and lower ends thereof.

wave guide in a direct, simple and el'licient man- When such a magnetron is placed between nel" suitable magnetic poles Illv to create a longitudinal Another object of this invention is to devise l5 magnetic field and the device is energized; OSCil the above type 0f Couplmg so that the tmpedantes lations are set up with the opening between each @t the Varous parts Qt the System al? ntttchett pair of plates 5 operating as a. tuned oscillating Wlth eactt other by mlPedance ttutltltmg 0l cavity. These, oscillations are-fed, yby means of a t1" anstomm? means of ampie. con gutttlqtll construction tov be described below, into a hollow The foegomg and other 0 Jeets of 1s mt'eu' wave guide l5, preferably of a rectangular crosstion will be best understood from the following 3" q 1 ectlon and foirned of a suitable conducting matedescriptlon of exemphcations thereof, reference rial, Such as copper. The wave. guide l5 is wrapbeing had to the accompanying drawings, wherepedi around the Outside of the envelope i, prefelm m: c ably with the long dimension of the cross-seotion mt fln rotlatrgf iree eirllofdi 1.,-, of said wave guide l 5 in contact with the enternal Fig 2; waiglcofuthe elziveloetl. J'GIlhe wavci guidie llis her; I. l me 1 a y so ere o e enve ope wiere 1 iinlfalfaigganisyerse 'Cross Sectmn taken along comes in contact with said envelope. The wave Fig- 3 is a Vi,EW similar to Fig 2 of another em guide l5 is closed at one end t5, and is connected bodiment of my invention; i( at the other end through a choke coupler il to Fig [i is a fragmentary Cross sectlon taken an additional wave guide I8 through which the adong line ,i of Fig. 3; oscillations may be led to an external utilization Fig. 5 is a fragmentary transverse cross-section uevlce' In Order to Complete the hermetm Seat of another embodiment of my invention; and ai glass member l 9 may be Seated-acr9ss that por Fig. 6 is a fragmentary ci.oss seciion taken is tion of the chole coupler Il which 1s connected along une e-e of Fig. 5. t0 the Wave gulde t5 The magnetron illustrated in Figsl and 2 In order to feed the oscillating energy directly comprises a tubular envelope l made of a cylinder into the Wai/e guide l5, a plurality of coupling of Conducting material such as Copper. en@ IOODS are loated in Selected OSC'Hat/ng 'CaV" of the envelope are Covered ,by Caps 2 and 3 likeil ties between adjacent anode plates 5. One end wise formed of conducting material, such as of each of said coupling loops 2B is imly and copper, and hermetically soldered in place on electrically Connected t0 the inner Woll 0f the the ends of the envelope |.The envelope l is envelope l. Theother end of each of the loops formed with a central annular projection fs. A 23 S Connected t0 a COIldllCOl 2| Which extends plurality of radially-disposed plates 5 are soldered 4.5 through an opening 22 in the. side Walls of the in place along the inner sur-face of the projection enveope l into the interior of the wave guide l5 The inner ends of the radial plates 5 are where said conductors 2| serve as exciting probes adapted to serve as anodes and receive electrons for said wave guide.

emitted from a `centrally-disposed cathode 6, For max mum eiciency the probes 2l should which is preferably of a thermionic indirectly- 5o feed energy into the wave guide l5 in the proper heated oxide-coated type. lIhe cathode 6 is prophase relation to the Wave propagated through vided with an internal heater 'l and an outer consaid wave guide to reinforce the wave by being ducting sleeve B, preferably coated with the usual in phase agreement therewith. If, for example, thermonically-emitting oxide coating. The heatthe loops 2i] are located in cavities which oscillate er 'i is provided with a pair of end conductors il 55 in time phase With each other, then the probes 2| should bespa-ced apart along the wave guide I5 by a distance mkg 2 Where 11.1 is an even Whole number and xg is the wave length of the radiations within the wave guide I5. If, however, the loops are located in cavities which oscillate 180 out of time phase with each other, then the probes spaced apart along the wave guide I5 by a distance mkg 2 where m is an odd whole number. The closed end I6 is located the proper distance from the adjacent probe 2|, so that radiations which are propagated toward said closed end I6 and are reflected therefrom combine with the radiations propagated in the opposite direction in phase agreement therewith so as to produce a resultant propagation of the hyper-frequency energy in a direction through the wave guide I5 toward the choke coupler I'I and the external wave guide I8. Y

extend from predetermined oscillating cavities within the magnetron through the walls of the envelope I and into the wave guide I5. The tapered slots 23 Serve as impedance matching elements so that the impedance of the oscillating cavities is matched to the impedance of the wave guide. For this purpose the inner end of each slot 23, looking into the oscillating cavity within the magnetron, is suiciently smaller than the outer end of said cavity 23, looking into the wave guide I5, so as to produce the necessary impedance matching.

Instead of matching the impedances through tapered slots, as described in connection with Figs. 3 and 4, impedance transforming slots 24', as illustrated in Figs. 5 and 6, may be utilized. Each slot 24 is provided with a section 25 of increased length, looking into the oscillating cavity, and connected with a section 26 of decreased length, looking into the wave guide I5. The shoulder 2'! between the sections and 2S introduces an impedance transforming discontinuity which together with the sections 25 and 26 results in the desired impedance matching.

It is desirable that the standing wave ratio adjacent the choke coupler be as low as possible in order that a maximum of energy be propagated through the wave guide section I8. This ratio in the embodiment described above may be reduced by causing the amount of power fed into the wave guide section I5 to increase progressively as the choke coupler I'I is approached. This may be done in Figs. l and 2 by adjusting the length of the probes 2S to be progressively greater. Likewise in Figs..3-6, the coupling slots may be ad justed to be progressively larger. Also the standing wave ratio can be reduced by dissipating some of. the energy at the closed end I6 of the wave guide section I5, as by coating the inside surface of said end I6 with a resistance material. Also a slight deviation of the probes of Figs. 1-2 and 2I should be CTI the slots of Figs. 3-6 from that as described above Will tend to reduce said standing wave ratio.

Of course it is to be understood that this invention is not limited to the particular details as described above as many equivalents will suggest themselves to those skilled in the art.

What is claimed is:

1. A high frequency oscillator comprising an electron discharge tube having a plurality of electromagnetically coupled cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, a plurality of said cavity resonators being directly coupled to said wave guide-said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator.

2. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, a plurality of said cavity resonators being directly coupled to said wave guide at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator.

3. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, each of said cavity resonators being directly coupled to said wave guide through an impedance matching slot, said slot having predetermined cross-sectional dimensions looking into said cavity resonator and diierent cross-sectional dimensions looking into said wave guide, whereby the impedance of said cavity resonator is matched to the impedance of said wave guide.

4. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity reso nator, each of said cavity resonators being directly coupled to said wave guide through an impedance matching tapered slot, said slot having predetermined cross-sectional dimensions looking into said cavity resonator and diierent cross-sectional dimensions looking into said wave guide, whereby the impedance of said cavity resonator is matched to the impedance of said wave guide.

5. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, each of said cavity resonators being directly coupled to said wave guide through an impedance transforming slot, said slot having substantially uniform predetermined cross-sectional dimensions looking into said cavity resonator and extending through said slot for a predetermined distance and different substantially uniform predetermined cross-sectional dimensions looking into said wave guide and extending the running distance through said slot, whereby an impedance transforming discontinuity is produced within said slot.

6. An electron discharge device comprising a cathode, an anode, said anode having a plurality of electron-receiving portions disposed around said cathode, and a plurality of grooved portions spaced from said first portions and likewise disposed around said cathode, said grooved portions constituting cavity resonators, a hollow wave guide wrapped around said anode, a plurality of guide wrapped said cavity resonators being directly coupled to said wave guide, said wave guide having an end section through which the oscillatory energy is led out of the oscillator.

7. An electron discharge device comprising a cathode, an anode, said anode having a plurality of electron-receiving portions disposed around said cathode, and a plurality of grooved portions spaced from said rst portions and likewise disposed around said cathode, said grooved portions constituting cavity resonators, a hollow wave around said anode, a plurality of said cavity resonators being directly coupled to said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator.

8. An electron discharge device comprising a cathode, an anode, said anode having a plurality of electron-receiving portions disposed around said cathode, and a plurality of grooved portions spaced from said rst portions and likewise disposed around said cathode, said grooved portions constituting cavity resonators, a hollow wave guide wrapped around said anode, a plurality of said cavity resonators being directly coupled to said wave guide at a plurality of points spaced along said wave guide, said wave guide having an end section through which the oscillatory energy is led out of the oscillator.

9, An electron discharge device comprising a cathode, an anode, said anode having a plurality of electron-receiving portions disposed around said cathode, and a plurality of grooved portions spaced from said rst portions and likewise disposed around said cathode, said groove portions constituting cavity resonators, a hollow wave guide wrapped around said anode, a plurality of said cavity resonators being directly coupled to said wave guide at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator.

10. A magnetron comprising a cathode, an anode, said anode having a plurality of electronreceiving portions disposed around said cathode, and a plurality of grooved portions spaced from said rst portions and likewise disposed around said cathode, said grooved portions constituting cavity resonators means adjacent said cathode for producing a magnetic field transverse to the discharge path between said cathode and said electron-receiving portions, a hollow wave guide wrapped around said anode, a plurality of said cavity resonators being directly coupled to said wave guide. said wave guide having an end section through which the oscillatory energy is led out of the oscillator.

11. A magnetron comprising a cathode, an anode. said anode having a plurality of electronreceiving portions disposed around said cathode, and a plurality of grooved portions spaced from said rst portions and likewise disposed around said cathode, said grooved portions constituting cavity resonators, means adjacent said cathode for producing a magnetic eld transverse to the discharge path between said cathode and said electron-receiving portions, a hollow wave guide wrapped around said anode, a plurality of said cavity resonators being directly coupled to said wave guide at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator.

12. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, a hollow Wave guide adapted to be excited by said cavity resonators, a plurality of said cavity resonators being directly coupled to said Wave guide at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator, and energy dissipating means at said closed end.

13. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, a hollow wave guide adapted to be excited by said cavity resonators, a plurality of said cavity resonators being directly coupled to said wave guide at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator, and means at said coupling points for progressively increasing the energy fed into said Wave guide from said cavity resonators as said opposite end section is approached.

14. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, each of a plurality of said cavity resonators being directly coupled to said wave guide by a probe at a plurality of points spaced along said Wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator, said probes being progressively longer as said opposite end section is approached.

15. A high frequency oscillator comprising an electron discharge tube having a plurality of cavity resonators therein, and a hollow wave guide adapted to be excited by said cavity resonators, each of a plurality of said cavity resonators being directly coupled to said Wave guide by a coupling slot at a plurality of points spaced along said wave guide, said wave guide having a closed end and an opposite end section through which end section the oscillatory energy is led out of the oscillator, said coupling slots being progressively larger as said opposite end section is approached.

DONALD M. POWERS.

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

UNITED STATES PATENTS Number Name Date 2,084,867 Prinz et al. June 22, 1937 2.088.749 King Aug. 3, 1937 2,108,900 Peterson Feb. 22, 1938 2,147,717 Shelkunoi'f Feb. 21, 1939 2,151,157 Shelkunoi Mar. 21, 1939 2,153,728 Southworth Apr. 11, 1939 2,154,758 Dallenbach Apr. 18, 1939 2,190,668 Llewellyn Feb. 20, 1940 2,247,077 Blewett et al. June 24, 1941 2,284,405 McArthur May 26, 1942 2,411,151 Fisk Nov. 19, 1946 2,411,953 Brown Dec, 3, 1946 2,421,912 Spooner June 10, 1947

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