US2513371A - Thermally tunable cavity resonator electron discharge device - Google Patents

Thermally tunable cavity resonator electron discharge device Download PDF

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Publication number
US2513371A
US2513371A US575585A US57558545A US2513371A US 2513371 A US2513371 A US 2513371A US 575585 A US575585 A US 575585A US 57558545 A US57558545 A US 57558545A US 2513371 A US2513371 A US 2513371A
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Prior art keywords
anode
frequency
cathode
heat
cavity resonator
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Expired - Lifetime
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US575585A
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English (en)
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William G Shepherd
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AT&T Corp
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Bell Telephone Laboratories Inc
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Priority to BE475488D priority Critical patent/BE475488A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US575585A priority patent/US2513371A/en
Priority to CH265985D priority patent/CH265985A/fr
Priority to FR946926D priority patent/FR946926A/fr
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Publication of US2513371A publication Critical patent/US2513371A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • H01J25/22—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone
    • H01J25/24—Reflex klystrons, i.e. tubes having one or more resonators, with a single reflection of the electron stream, and in which the stream is modulated mainly by velocity in the modulator zone in which the electron stream is in the axis of the resonator or resonators and is pencil-like before reflection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/06—Tubes with a single discharge path having electrostatic control means only
    • H01J21/08—Tubes with a single discharge path having electrostatic control means only with movable electrode or electrodes

Definitions

  • This invention relates to electron discharge devices and, in one practical embodiment, to a reflex oscillator of the types disclosed in the applications Serial No. 575,584, filed February 1, 1945, of S. O. Ekstrand and E. J. Walsh jointly and Serial No. 575,586, filed February 1, 1945, of F. H. Best, to the extent that the present invention relates to the thermal tuners for the cavity resonators thereof. This is especially true of the first-mentioned, and the later numbered figures of the drawing for the present application will be found to be substantial duplicates of certain of the figures thereof, said Ekstrand and Walsh invention relating to structural details of the oscillator tube as a whole.
  • the principal object of this invention is to provide a means for tuning a cavity resonator by change in its dimension which is exceedingly rapid, while at the same time, perhaps contrary to normal expectation, facile and sensitive, in operation. Additional, and more specific objects, will be evident from the following brief statement of the physical structure and attributes of the tuning system of the invention.
  • the invention makes use of thermal tuning and, therefore, to a distortion or dimensional change of the cavity resonator by the application of a stress, with a resultant strain, induced by thermal expansion.
  • a thermal tuner which is older in the art, in which the heat, upon which the necessary expansion is predicated, is generated by a current flowing through the strain-producing element itself, or
  • the heat has the great advantage as to flexibility, sensitivity, availability of standard supply sources and the like.
  • the device of the invention has the great advantage of possibility of remote control.
  • the invention while applicable generally to electrical tuning is especially adapted to the tuning of cavity resonators, where positional control of the significant tuning element is of relatively great importance. Its application is not limited to the cavity resonators of reflex oscillators although perhaps having its best exemplification therein.
  • the invention may be used with external regulation of the difference of potential by means of which the control is effected.
  • the invention also contemplates certainspecific detail of the tuning system whereby its effectiveness, in the aggregate, may be very greatly increased.
  • the bombarded element may with advantage be coated with a zirconium product to aid the getting operation when the tube is being evacuated, and which subsequently,
  • the heating of the bombarded element should be derived as much as possible from the electronbombardment, since this can so easily be controlled, so that heat radiation directly thereto from the cathode should be minimized, as by the use of as small a solid angle as possible subtended by the bombarded element with respect to said cathode.
  • plating on said parts would tend to prevent their heating to above a critical temperature by providing a path for rapid heat dissipation by conduction. This feature is especially useful in view of the desirability and use of a particular alloy for the element most in 'question which itself does not have a very high heat conductivity.
  • FIG. 1 represents, partly in section, a highly diagrammatic and simplified version of what at leastin part is shown in accurate detail in difierent views by Figs. 3 and 4, to teach the basic prinassembly included in the device illustrated in Fig. 1,. portions'of this assembly being broken away to show details thereof more clearly.
  • cavity resonator l! might well be the resonator of a reflex oscillator of Figs.
  • the coaxial line IE4 provides an alternating current coupling to the resonator for whatever purpose desired depending on the specific attributes of the organization as a whole.
  • the significant element for present purposes is the elastic diaphragm I05, by a movement of which normal to its direction of extension its spacing from the nearest adjacent wall section in the path of the beam may be varied with the consequent variation in tuning of the resonator, together with the means for actuating said diaphragm.
  • the resultant thermally induced movement of the ends of element 16 is transmitted to the diaphragm through bows I08 Whose material or operating temperature or both are such that they do not expand materially and a mechanical coupling principally comprising yoke I09 rigidly attached to the diaphragm.
  • the tuner unit has rigid attachment to and support by the supporting element llil by element III.
  • the bows are rigidly attached to the ends of the anode IE6 but the bow-ancde-cathode assembly is loosely mounted in the support so as to accommodate a sufficient longitudinal movement (that is longitudinal only with respect to the direction of electron flow from gun I02) to make possible a, frequency adjustment of the resonator as a direct function of such movement.
  • the tuning movement of the diaphragm is a function of the thermal condition of the bombarded element which itself is a function of the potential impressed between it and the cathode which determines the number and velocity of the bombarding electrons. varied as desired for'that purpose.
  • Reference numeral H2 diagrammaticallyindicates a variable direct potential source with this in mind and reference numeral H3 similarly diagrammatically shows a source of exciting current for said cathode. It is, of course, obvious that indirect heating could alternatively be used for said cathode, as in fact would be desirable, and that many other changes could be made in the organization without affecting the principle of operation of the invention.
  • Fig. 2 indicates, in general, how the external control may be automatic. Some portion of .the
  • This potential may be output of thecontrolled oscillatorwould be fed into the discriminator circuit which would then convert a frequency deviation from the desired frequency into a potential'having a sign dependent upon the direction of the arrow. 'This potential would then'be amplified-and fed into the thermal tuner device.
  • the frequency f required by the" system could'well be, alternatively, the difference frequency of the transmitter-heterodyne receiving system mentioned in the statement of invention.
  • the functional labeling in Fig. 2 obviates the necessity for other labeling of the parts. i
  • the following analysis indicates a quantitative basis for a design of the thermal control system of the invention; a
  • H the heat content produced by electron bombardment of the control system.
  • the time rate of change of heat content will be To a first approximation the frequency error, 6 will be proportional to the change in gap spacing required to compensate for this error, i. e.
  • the thermal tuning system will have a thermal displacement characteristic given by some function
  • (1) 3 should be large. This relates the change of gap spacing of the resonant cavity to the change of resonant frequency. If B is to be large the gap spacing should be small. However, the gap spacing is usually dictated by electronic considerations and must therefore be considered a criminator-circuit, i. e., the factor a. should be made large.
  • the factor C should be made small. This is to be expected since it states that'the volume and specific heat of the tuning system shall be small. This is analagous to saying that the amount of energy stored in electrical circuit should be small if 'a rapid response is desired.
  • Equation 8 it will beantail for tun-ing a particular reflex oscillator unit that has been found effective in practice. As was indicated in the statement of invention this disclosure will be the same as that for the Ekstrand and Walsh application filed concurrently herewith except for the few modifications of certain of the elements constituting a part of the present invention, also noted in the statement of invention.
  • the electron discharge device therein illustrated comprises a highly evacuated enclosing vessel including a metallic,
  • the base I! has joined thereto a plurality of eyelets H to which a plurality of leading-in conductors l3 are sealed hermetically by vitreous beads M, and has joined theretoalso an eyelet l5 to which a conductor H5 is sealed hermetically by a vitreous, bead IT.
  • 3 are connected to terminal pins I8 carried by an-insulatingdisc l9 mounted from the base H the conductor l6 constitutes a part of a coaxial line, the outer conductor 23 of which is defined in part by an elongated cylinder depending from the base Mounted within the enclosing vessel IO, N are 1 a cavity resonator assembly, an electron gun and a thermionic tuner assembly.
  • the resonator assembly' comprises a metallic member having a cylindrical flange 2 l, adapted to fit slidably within the cylindrical portion ll!
  • the metallic member having also a dished portion 22 eccentric with respect to the flange 2
  • I .Secured to the intermediate portion 25, as by welding, is a concentrically corrugated, centrally apertured, metallic diaphragm 28, which Iimay also be radially slotted, which mounts a --d ished driving or. coupling member 29 havin therecnue number of tabs :30.
  • the aperture-.111 the diaphragm 28 is-coaxial with the aperture :23 andhasextending thereacross a concave-convex grid 3
  • the slots in diaphragm 28 extend as nearas maybe to the inner and outer periphery of-the diaphragmexclusive of the grid 3
  • the dished portion 22, diaphragm 28'and outer eyelet 26 bound a substantially toroidal cavity having therein a gap bounded by the grids 2,7 and 3]. Because of the construction of the grid assembly 25, 2'1, it will be appreciated-that the S111? faces of this assembly forming portions of the boundary walls of the cavity are accurately controllable and fixed so that the cavity constants and, hence, the cavity frequency conform accurately to prescribed values.
  • the resonant frequency of. this cavity is dependent upon the position of the diaphragm 28 and is adjustable by flexing the diaphragm in the manner described hereinafter.
  • a metallic cup-shaped member 32 Supported from the dished portion 22 is a metallic cup-shaped member 32. having thereon a cylindrical sleeve 33 in which a metallic conductor 34 is telescopically fitted, the latter being supported from the base I and coaxial with the conductor Hi.
  • the inner vendof the conductor 46 is reversely bent as shown at 35 and a-flixe'd to the sleeve 34 to define a coupling loop between the resonant cavityand the coaxial line It, 20, 34.
  • a frusto-conical member 31 which constitutes the end :or nose electrode of an electron gun.
  • the electron gun includes a cathode member 38 having a concave electron emissivesurface -38 coaxial with the electrode 37, and a cylindrical beam forming electrode 43 coaxial with the emissive surface and mechanically coupled to the cathode member 38 by a ring M and a plurality of wires or strips 42, only one of which is shown.
  • the unit comprising the cathode member and beam forming electrode is supported from an insulating disc 43 by a flanged collar 44 locked to the disc by tabs 45, the disc being supported, in turn, by the member 32 to which it islocked by tabs 46.
  • a heater filament is disposed within the cathode member 38 and is supported, by extensions thereof, from two of the leading-in conductors l3.
  • the emissive surface 39 and electrodes, 31 and 43 are constructed and arranged, in ways known in the art, so that electrons emanating from the .emissive surface are concentrated into a converging beam substantially focussed upon the gap between the grids 21 and 3
  • a cup-shaped repeller electrode .48 Opposite the grid 3
  • mount also a thermionic tuner assembly, shown in detail in Fig. 4.
  • This assembly comprises a pair of parallel insulating plates 52 seated upon the plate 49 and held in spaced relation by a channeled "anode 53 to which they are locked by metallic strips 54.
  • the anode 53 is provided with extensions 55 "flattened cathode member 56 enclosing a heater element 51, for example a W-shaped filament coated with insulating material, the ends of the filament being connected to wires or rods 58 which extend between the plates 52 and are connected to certain of the lead-in wires I3.
  • the surface 59 of the cathode member toward the anode 53 has thereon a coating of electron emmissive material.
  • the heated element that is the anode
  • the tuner may be aided, in the case where the principal cooling is caused by radiation, by improving the black body characteristics of the anode of the tuner.
  • This characteristic may conveniently be achieved by the use of zirconium sprayed on all the'surfaces of the anode except that directly exposed to the tuning bows. The zirconium then serves a double function, because of its physical characteristics as sprayed on it has a good black body constant and because of its chemical characteristics it serves as a getter for gas emitted by the anode.
  • the cathode is encompassed by a flattened helical grid 60 carried by a pair of wires or'posts 6
  • the anode 53 is connected electrically to the cavity resonator by way of the studs and the cathode 56 and electrodes 62 are connected in common to one of the leading-in conductors I3 by the strip 63.
  • the rods or wires 58, to which the ends of the heater 5'! are connected as noted heretofore, are connected to respective conductors i3 by the wires 64 and the grid 60 is connected to another of the conductors l3 by a tie Wire 65.
  • the repeller electrode 48 is associated electrically With another conductor l3 by a tie wire 66 aflixed to one of the tabs 50.
  • a laminated bow member 61 Associated with the anode 53 is a laminated bow member 61 the ends of which are afiixed as by welding, to the anode at points in alignment with the studs 5! to which the anode extensions 55 are secured.
  • the bow member 61 has welded thereinto a rigid cross-piece 68 Which mounts a pair of rigid parallel rods- 69 fixed thereto and to the tabs30 in the driving member 29.
  • the anode 53 and bow member 61 are constructed of materials-Which should have widely different temperature coefficients of expansion and contraction. if equally exposed to temperature conditions,.in. order to insure the requisite differential operating'effect. Of course this dif ferential effect could be otherwise insured'while permitting use of like'materials for the tWO elements by sufficient differentiation of exposure to the heat or, which'amounts to .the same .thing,
  • theanode may be of a material, such as stainlesssteel, having a high;
  • thebow member may be of a material, such as an alloy of iron. cobalt and nickel known as Kovar, having'a low temperature'coefiicient.
  • a material such as an alloy of iron. cobalt and nickel known as Kovar, having'a low temperature'coefiicient.
  • the bow should be effected only by the mechanical traction applied to it, so as to be thermally unaffected, it has been found very desirable to plate the bow, (the laminations thereof where laminated) with a high conductive ity material such as copper. This enables the bow to rapidly dissipate any heat which tends to be generated in it, as by radiation from the cathode or anode.
  • the preferred alloy that is, the Kovarf above mentioned whileextremely desirable for other reasons, has a particular form of non-linear temperatureexpansion characteristic that would tend to effect its operation asathermally stable element when its temperature exceeds a super-threshold value.
  • the copper plating insures that it does notexceed this value.
  • longitudinal expansion and contraction of the anode which action may be relatively free due to the flexibllity of theunfixed portion of the extensions 55, results inbowing of the member 61. to a lesser or greater extent, whereby the cross-piece 6B is moved in the direction at right angles to alteration of the dimensions of the resonant" cavity, and consequently, in the resonant frequency of the cavity.
  • the length of the anode at any time is determined by the anode temperature and this in turn is determined by the bombardment thereof by electrons from the cathode 56.
  • the anode current is controlled by the potential of the grid 60.
  • the resonant frequency of the cavity resonator may be adjusted or maintained substantially fixed at a prescribed value despite variations in the configuration of the cavity due to temperature effects.
  • tuner and resonator may be fabricated readily as individual assemblies which may then be associated by aifixing the anode extensions 55 to the respective studs 5
  • the diaphragm 28 is flexed by'adjustment of: the position of the rods, as bya differentialscrew in a suitable fixture, to tune the cavity resonator to a preassigned frequency.
  • the rods are then secured to the cross-piece While. held in the-adjusted position.
  • the diaphragm is fixed initially, accurately at such position that during operation of the deviceit'v can be flexed to vary the material frequency of thecavity over a desired prescribed range.
  • An oscillator comprising a mechanical-electrical network the natural frequency of which determines the characteristic frequency of oscillations including a movable element the position of which affects a frequency significantdimension of said network, means for exciting said circuit organization to cause it to oscillate at its natural frequency; a cathode and an elongated anode,-- a mountingmeans for said cathode and anode, a bow-like elastic element connected adjacentits respective ends tosaid anode, said anode having a high temperature coefficient of expansion and contraction as compared with said bUW-Jik elementwhereby its" length varies in accordance with the heat induced by its bombardment by electrons from saidcathode and means for aligning said mounting means and its attached anode and bow-like element so that said bow-like element is generally coplanar with said movable element whereby the resultant transverse movement of the bow-like element consequent on the thermally-induced changes in length of said anode are in the direction of the desired movement of said movable
  • said bow-like element comprises two diverse metals one, as compared with the other. being most effectiveas an elastic material and the other, as compared with the first, being most effective asa heat conductor.

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US575585A 1945-02-01 1945-02-01 Thermally tunable cavity resonator electron discharge device Expired - Lifetime US2513371A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE475488D BE475488A (enrdf_load_stackoverflow) 1945-02-01
US575585A US2513371A (en) 1945-02-01 1945-02-01 Thermally tunable cavity resonator electron discharge device
CH265985D CH265985A (fr) 1945-02-01 1946-09-17 Dispositif électronique pour commander l'accord d'un circuit, notamment d'un résonateur à cavité.
FR946926D FR946926A (fr) 1945-02-01 1947-05-19 Dispositifs à décharge électronique

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US575585A US2513371A (en) 1945-02-01 1945-02-01 Thermally tunable cavity resonator electron discharge device

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US2513371A true US2513371A (en) 1950-07-04

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BE (1) BE475488A (enrdf_load_stackoverflow)
CH (1) CH265985A (enrdf_load_stackoverflow)
FR (1) FR946926A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754447A (en) * 1951-12-06 1956-07-10 Hartford Nat Bank & Trust Co Very high frequency electric discharge device
US2856556A (en) * 1954-10-21 1958-10-14 Bendix Aviat Corp Electron discharge device
US2866123A (en) * 1953-12-02 1958-12-23 Raytheon Mfg Co Mechanically tuned klystrons
US2881350A (en) * 1953-12-23 1959-04-07 Siemens Ag Reflex klystron-type electron tube
US2900561A (en) * 1953-12-15 1959-08-18 Bendix Aviat Corp Electron discharge device
US3197546A (en) * 1962-07-23 1965-07-27 Gen Electric Getter support assembly

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1419547A (en) * 1918-11-12 1922-06-13 Cornelius D Ehret Electronic apparatus
US1565151A (en) * 1919-12-27 1925-12-08 Western Electric Co Electric discharge device
US1740202A (en) * 1922-04-11 1929-12-17 Ruben Patents Company Electron-tube apparatus
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2374810A (en) * 1939-12-22 1945-05-01 Int Standard Electric Corp Electron discharge apparatus
US2408817A (en) * 1943-11-29 1946-10-08 Sperry Gyroscope Co Inc Electron discharge apparatus
US2413385A (en) * 1945-03-23 1946-12-31 Raytheon Mfg Co Electron discharge device of the magnetron type
US2414785A (en) * 1942-01-29 1947-01-21 Sperry Gyroscope Co Inc High-frequency tube structure
US2429295A (en) * 1943-03-13 1947-10-21 Westinghouse Electric Corp Tuning means for magnetrons
US2438132A (en) * 1943-11-29 1948-03-23 Sperry Corp Electron discharge apparatus
US2454306A (en) * 1948-11-23 clifford et au

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2454306A (en) * 1948-11-23 clifford et au
US1419547A (en) * 1918-11-12 1922-06-13 Cornelius D Ehret Electronic apparatus
US1565151A (en) * 1919-12-27 1925-12-08 Western Electric Co Electric discharge device
US1740202A (en) * 1922-04-11 1929-12-17 Ruben Patents Company Electron-tube apparatus
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2374810A (en) * 1939-12-22 1945-05-01 Int Standard Electric Corp Electron discharge apparatus
US2414785A (en) * 1942-01-29 1947-01-21 Sperry Gyroscope Co Inc High-frequency tube structure
US2429295A (en) * 1943-03-13 1947-10-21 Westinghouse Electric Corp Tuning means for magnetrons
US2408817A (en) * 1943-11-29 1946-10-08 Sperry Gyroscope Co Inc Electron discharge apparatus
US2438132A (en) * 1943-11-29 1948-03-23 Sperry Corp Electron discharge apparatus
US2413385A (en) * 1945-03-23 1946-12-31 Raytheon Mfg Co Electron discharge device of the magnetron type

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754447A (en) * 1951-12-06 1956-07-10 Hartford Nat Bank & Trust Co Very high frequency electric discharge device
US2866123A (en) * 1953-12-02 1958-12-23 Raytheon Mfg Co Mechanically tuned klystrons
US2900561A (en) * 1953-12-15 1959-08-18 Bendix Aviat Corp Electron discharge device
US2881350A (en) * 1953-12-23 1959-04-07 Siemens Ag Reflex klystron-type electron tube
US2856556A (en) * 1954-10-21 1958-10-14 Bendix Aviat Corp Electron discharge device
US3197546A (en) * 1962-07-23 1965-07-27 Gen Electric Getter support assembly

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Publication number Publication date
FR946926A (fr) 1949-06-17
CH265985A (fr) 1949-12-31
BE475488A (enrdf_load_stackoverflow)

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