US2394397A - Ultra high frequency tube - Google Patents

Description

. MoURoMTs'Ex-'F ET Al. 2,394,397'

Feb. 5, 1946.

ULTRA-HIGH FREQUENCYv TUBE Filed oct. 2'9, 1941 AT? FQ N EY Patented Feb. 5, 1946 2,394,397 Y ULTRAunioniFaEQUnNcv TUBE Ilia Emmanuel Mouromtseli, Montclair, and

George llvlichael' Dinnick, looineld, N, `J., as- Slsncrs to Westinghouse ElctiicCcriwraton, liastPittsburgh 4Pa., a corporation of Penn- Sylvania Application october 29, 1941 serial-*NQ- 416,934

lciso-'cvil 10 Claims- This invention relates to ultra high frequency tubesfand is particularly directed to the provision of :an -oscillationgeneraton of the'vacuumtype-for generating ultralhigh frequency Wave output. #In part-'it is a continuation of our copending AapplicationfSerial No. 360,367, ledv October 9, `1940.

Generation, of ultra f high l frequency oscillations for one purpose ori another isnotin itself a diflicul-t matter, butnumerous vlimitations of control and voutputhave 'been encountered. Priorart constructions utilizing vitreous envelopes kand lead-in `wires introduce inter-acting inductance and capacitance of l'such material import and magnitude as to' prevent adequate'tuningandto impair'utilzaticn of ultra high'frequency 'output therefrom. The maximu'm 'frequency at which the conventional tube operate isintrinsically limited 'more especiallyby vthe .physical obstacles governing the :propeninclusi'on and exclusion of inter-electrode andfinter-lead capacity as Well as inductance of the leads to the electrodes 7and other factors alfecting inductance and-capacity, since Yall such factors 'enter into the systemfby way of limtation'of 'the frequency .at-Which'the tube `vvill'operatel For instance, thezg'eneration of ultra high frequency oscillations byfknown threeelectrode tubes have their practical limitsfat approximately 500 to 600 megacycle'sper secondffor an outputof relatively very few Watts.

Thebasic 'reasonsrvunderlyingthe limitations of prior fart conventional tubes have explanation and foundation Ithe Afinite ytransit v.time of electrons and inthe physical and electrical difculties encountered 1in construction of an adequate oscillating circuit and'tube. `On the `one-hand, attain;- ment 'of Ythe mentioned 600 Y megacycle per second power out-put requires use-TofV high v'oltageswhich immediately injects necessityfor a tube structure physically too large for practically combiningit with vother structural parts andapparatus Cn the Vother lh'and, decreaseof :the inter-electrode capacity forincreasing the upper frequency limit at which a tube will operatalinvolves the'adverse characterizations of making .the electrodes smaller,'shorterAand--bringing the leads out of the envelope `at 'different or 'considerably separated points. In this connection, it may also besaid that the higher the frequency, the ygreater the adverse or damaging effect ofthe structural parts Yof the tube, 'since they offer adis'continuityin the oscillating circuit.

I l; "has heretofore been -proposed'to V*provide Aa hollow-#body resonator :intimately connected `with '-a vacuum tube so 'as to generate u'ltra #high fre- "quenc'y oscillations by `means fof diode relationshinof'partser-tneresonator.- Such a .0,f r;1str11c` tion produces 'a .continuous electron ow but is capable ofgenerating essentially very loW outputs at very=low-eiiiciency as Weak oscillations are superimposed on top ofthe-much stronger electronic'current flowing continuously. The ,prior art constructionreles upon the negative resistanceof the continuous electron iiow with vtransit time equal to 5A, 'Q /i, 1%4, etc., of the duration -of'an Voscillating cycle. Thepresent invention is a distinct'advanceover'such-a prior art construc tion in that We utilizea triode'built into an Veii'icient resonator rand produce an electronic Vcurrent Which iiows'periodically when thegrd voltage Vdoresintent it oif,

A11 Object of the',PTGSCnlL-lvelln' T10 P IOf vide a three-electrode oscillator with 'a single hollow-*body resonator `Without discontinuity.

'fl-further object of the `^invention is to provide a #generator of -lgllra -high frequency waves coinprising ,a tuned circuit enclcsed'within and includingits'envelope as part of the circuit.

A further object of the present invention is to obtain -c,scillatiorl` by an inductance-Capacitance f `circuit completed Within the device.

fi-further object of the present invention is to provide electrodes which are'inherentl'y portions offan' oscillating,r circuit Without intervening conducting leads Y -Af'urther-pbject of the present inventionris torrovide a high frequency oscillator capable of .eilcently establshingfa h gh'fqrequency outimt-v -Another object of the invention is to enable theioscillatorto be tuned `Within a certainnarrow band of frequencies.

Another object of the inventionisto vary the frequency, Within limits, Without necessity of opening the-envelope.

A further object ofthe invention is to expedite centrolvof `rthe oscillating frequency olfvultra high frequency electron discharge devices.

"A still further object of the invention -is topincolporate theelectrode elements Within-a1-rnetallic resonator 'both for Abenefits above-.given and to prevent external radiation. l

Yet'again, anobjectof the `inventionis to-provide `a mechanically robust construction of 4selfcontained ultra vhigh frequency oscillator.

Further objects of the invention include -provision of a structure adaptable to better cooling, simplicity of fabrication, stability `of Operation, and Aother'advantagesand results which Will appear to those Askilled in the art, 'bnthcby direct statement thereof and 'by implication from the context.

-and a resonator.

tion I2 is a cathode 25.

sealed thereat as by welding, brazing, silver sol- Y Suice it to say that said tubular portion and bottom plate constitute a i In the specific embodiment of the invention illustrated in said drawing, the reference numeral I indicates a preferably right-cylinder` hollow body constituting both an evacuated envelope Said envelope-resonator IllV preferably includes as its outer shell a lmetallic cylindrical outer side wall IIA and coaxial therewith an inner elongated reentrant tubular por- Y tion I2. The forward reentrant end of this said inner portion is formed in suitable Vmanner as a mesh or perforate fiat grid I3. Below the grid and within said inner or reentrant ,tubular por- Y What may be termed for convenience in description as the upper or Aforward end wall of the cylinder in proximity to and parallel to said grid, is shown as a separately formedperipherally flanged end or cover member I4 of this rigid metallic construction. Next the inner face of this cover member and of substan- V tially the same diameter thereas Vso as to nest therein, is a iieXible metallic diaphragm I5. As to this feature, the present invention is in part a continuation of our former copending appli-V cation, Serial No. 360,367, filed October 9, 1940.

Said diaphragm likewise may be peripherally flanged but with its flange of less depth than that ofthe: cover member. The flange of thel diaphragm is preferably vacuum sealed peripherally to the side wall II of the cylinder next its end, vas by silver soldering or otherwise. Cathode, grid and anode accordingly-are present as a tube triode, with a portion of the grid'and anode structures also forming a resonator chamber.

The Vflange of the cover member lI4 may be Y' given a threadedengragement with the marginal Yend portion of the cylinder and thus form a closure for the end of the cylinder and effect a clamping of the peripheral margin or flange of l the diaphragm in place andr prevent the vacuum Y -seal from becoming disrupted in'use. After assembly oftheseV several parts as just described,

the threaded joint between the cover ange and the cylindrical side wall I I also may be'rendered vacuum tight, if desired, by silver soldering-or otherwise. n

The diaphragm I5 is resilient and is inherently fiat across its body portion, vbut may be lexed' or convexed centrally inward toward grid. I3 by means such as a thumb-screw I6 situated centrally of and through said cover member I4. Spacing between grid and diaphragm may 'accordingly be delicately adjusted and with the diaphragm functioning as an anode, tuning of the resonator is effected.

A't-what may be termed the bottom of the envelope is a metallic bottom plate or wall, II parallel'to the cover member. Said bottom plate is annular, and receives the reentrant tubular portion I 2 throughfits central opening.V As a convenient mode of fabrication, .the lower end of said tubular portion is provided with a radially outwardly projecting peripheral fiange I8 which is brought atwiseagainst the under side use of Kovar.

dering or otherwise.

physical and electrical entity.

The outer periphery of the bottom plate I'I is flanged downward, as at I9, and feather-edged, said ange being of slightly less diameter than the inner diameter of the cylinder wall I I so the flange and end margin'of said cylinder wall willconstitute a capacitance. VA dielectric bead 20 overlies and enters spacing thereofrand to provide a vacuum seal thereat. rSaid bead may conveniently be comother are parallel for obtaining optimum capacitance relation. y

A metallic nipple 2I is silver soldered or otherwise vacuumv sealed with respect to the tubular portion I2 and protrudes from the lowervend thereof, said nipple having its Alower end tapered to a featheredge and sealed in a reentrantglass stem 22, the press end 23. whereof is well within and shielded by the said tubular portion. Leadin wires 24 pass upwardly through the" reentrant glass stem and press and support and feed an electron emitting cathode 25 somewhat below the grid and parallel thereto.v Source of electrical energy (not shown) is applied across the terminals for the lead-in wires 24, as usual. A batteryy 26 Vis shown applying a grid bias from connection with one cathode lead and a connection 21 to nipple 2'I, which, with tubular portion 'I2 (both of which are metal) gives electricalcommunication tothe grid. Plate potential is shown :ap-

plied by battery 28 between .the grid terminal and fined to that produced-directly by the "grid kand Y anode themselves. Thestructure includes, briefly, a right-cylindrical portion Vwith which is as- Y sociated a tubular reentrant portion having ra fiat grid with the I cylindrical and tubular portions forming a hollow-body resonator chamber and a blocking capacitance. The grid has tunable relation to a'resilient eXible anode forming aswell one ,endY of the resonant chamber.

The inductance of the parts comprising the chamber enclosure resonant to th'e'frequency at Y which the device is intended to operate, in combination with thev self-contained capacitance, provides an inductance-capacitance ,oscillating circuit.

' A streamV of electrons emitted by cathode 25Y passes through grid I3 at a velocity determined 26. ferences involved in the high frequency field of the resonator, however, `are Vrelated tothe `oscillating grid potentials which should not be confused with the unvarying voltages, such as the grid bias, since the unvaryingvoltages. have no between said flange and end 'Y margin of the cylinder wall both to maintainthe The potential difcycli-c variation. Thesystem 'ishown 1-lisi rendered oscillatoryV and productive of high frequency energy from bunching of energy-'giving electrons. The cathode'- is spaced from thegrid -a= very `lsmall distance comparable'to a fraction lof thefvvave length sothat electrons-passing fromv cathode to grid (which occurs in-greatest number when the grid is'positive and in less number vvhenthe grid becomes negative) will gain energyfrom-the-grid circuit. These electronsV vcompnet-e their -journel from-gridto plate While thefgrid'ismore negative, the spacing of the ggridandplate 4being smail, commensurate to the cathode-grid spacing, 'and adjustable vlovthe exible plate or diaphragm; for that purpose. Energy accordingly is transferred to the vresonant circuit,` part *applying `as a feedback -to maintain oscillation and `.the rrbalance available 'for outputipurposes.

The hollowebodyresonator shown 'of `rightcylinder, reentrant "construction'is very isuitable for oscillations of the :above :specified frequencies,:an`d is particularly.advantageous foraccom plishment Yof objects-of our invention when cornbined, Vas indicatedto form athree-electrode'discharge tube. The wave length'kjgenerate'd by this structure and combination (as given vby F."B. Llewellyn and A. E. Bovven in an article'entitled lhe production ,of ultra-high -frequency oscillations by means of diodes, `appearing in .vol.'18 of The Bell ,System'Technical Journal, of, April, 1939, page '280 .et,seq.) may'befound 'fromthe expression:

where :c represents the 'distance between grid vand anode,A and in analyzed cases must be veryY small. Other symbols employed in this 'eduationfarefue which is the,insideresonatorheight; .rr the inside radius of the larger cylindricalbody portion; and r2 the radius to the outer 'face of Ythe reentrant cylindrical body portion I2. Accordingly a slight' change of h by the flexible diaphragm I5, will produce a noticeable change in generated frequency. 'I'his structure benecially eliminates one necessity to adjust the distances between the tube elements With an extreme accuracy when the device is assembled, and permits tuning to r a fixed output circuit.

It may furthermore be stated that two such devices may be used butt to butt for push-pull operation, and that other modifications and changes in structure and use may be made without departing from the spirit or scope of the invention, and it is to be understood we do not limit ourselves to the details of description or drawing, except as set forth in the following claims.

We claim:

l. A hollow-body resonator providing an evacuated chamber for high frequency oscillations, comprising a metallic right-cylinder portion and a metallic reentrant portion, one of said portions providing a grid and the other portion providing an anode each an inherent part of the respective portions Without discontinuity, a cathode adjacent said grid on the opposite side thereof from the anode, and means for deriving high frequency oscillating energy from the said chamber.

2. A hollow-body resonator providing an evacuated chamber for high frequency oscillations, comprising a metallic right-cylinder portion and a metallic reentrant portion, one of said portions provid-imgLa grid: and?y the fothenportionfproviding an Lanodeeacl'i an: inherentipart :ofthe: respective portions without ndiscontinuity, .said grid fand anode being substantially parallel to each Sother a Avsmall distance `apart 1 compared Lto the wavelength Lof the lhigh frequencyosciliations, and means for deriving high frequency oscillating energy fromrthe said chamber.

3. A hollow-body resonatorprovidingan evacuatedchamber for high frequency oscillations, comprising a metallic rightcylinder portion and a'metall-ic reentrant portion, one of saidportions providing -a grid and -the other portion providing an ano'de each an inherent part of the respective 4portions without discontinuity, said portions constituting inductance and having juxtaposedvareas lseparated by a dielectrioan'd constitutingacapacitance for introducing Va self-'contained inductance-capacitance oscillatory circuit in the resonator, a cathode adjacentsaidgridion the opposite sidethereof vfromlthe `anode, and means 'for deriving "high frequency oscillating energy fromV the said chamber.

4. A hollow-body resonator providing an evacuated chamber Yfor Ahigh "frequency oscillations, comprising a metallicfright-cylinder portion vand a metallic reentrant'portion, one of saidportions providinga grid and the other 'portion providing an-anode each an inherentA part of the respective portions Without discontinuity, a cathode .adjacent sai-d grid on the opposite side thereof from the anode, said grid and anode being-substantially parallel to each other 'a small distance Yapart compared tothe Wave-length of the high frequency oscillations, and leads'for'said anode 'and grid 4connected electrically thereto by connection at the outside of the resonator body 'to the respective right-'cylinder and reentrant portions. and means forderiving high frequency oscillating energy from the said chamber.

'5. 'A hollo'vvebody resonator providing an evacuated chamber lior high frequency oscillations, comprising Va metallic right-,cylinderportion 'and a metallic Areentrant portion,'one of said portions providing a grid and the other portion providing an anode each an inherent part of the respective portions without discontinuity, said portions constituting inductance and having juxtaposed areas separated by a dielectric and constituting a ca` pacitance for introducing a self-contained inductance-capacitance oscillatory circuit in the resonator, a cathode adjacent said grid on the opposits side thereof from the anode, leads for said anode and grid connected electrically thereto by connection at the outside of the resonator body to the respective right-cylinder and reentrant portions, and means for deriving highfrequency oscillating energy from the said chamber.

6. A hollow-body resonator providing an evacuated chamber for high frequency oscillations, comprising a metallic right-cylinder portion and a metallic reentrant portion, said reentrant portion providing a nat grid across its innermost end and the other portion providing an anode at the inner end of said right-cylinder portion next Said grid, said grid and anode each formed as an inherent part of the respective portions without discontinuity, said portions constituting a capacitance and having juxtaposed areas remote from the grid and an-ode and separated by a dielectric and constituting a capacitance for introducing a self-contained inductance-capacitance oscillatory circuit in the resonator, a cathode adjacent said grid on the opposite side thereof from the anode, said grid and anode beingsubf stantially parallel to each other'a small distance apart compared to the';Wave-length of the 'high frequency-oscillations, leads for said ano'deand 'grid connected electrically thereto by connection at Vthe outside of the Vresonator body to the respective right-cylinder and reentrant portions, and means for-deriving high frequency oscillating a energy from the said chamber. Y

7; A hollow-body resonator providing an evac-W uated chamber for high frequency oscillations, comprising a metallic right-cylinderportion and Va metallic reentrant portion, one of said portions providing a grid andthe other portion providing an anode each an inherent part of the Arespectivev portions Without discontinuity, said anode .comprising a diaphragm movable toward and away Yfdromthe said grid; means yexterior of the resonator body'for adjusting the anode-grid spacing While maintaining evacuation of said resonator body, a cathode adjacent said grid on the opposite side thereof from said anode, and means for deriving high frequency oscillating energy from the said chamber.

8. A hollow-body resonator providing an'evac-V Yuated chamber for high frequency oscillations,

phragm being resiliently flexible and tending to assume a normally flat condition, an end cover member for said cylinderportion overlying said diaphragm, a screw through said cover engaging a mid part of said diaphragm for flexing said diaphragm inward toward the grid While maintaining evacuation of said resonator body, a cathode adjacent said grid on the opposite side thereof from said anode, `and means for deriving high frequency oscillating Aenergy from said chamber.

9. A hollow-body resonator ,providingan uated chambery for high frequency oscillations, comprising a metallic Vright-.cylinder portion and a ,metallic reentrant portion, one of said portions providing a grid and the other portionvrprovidinlf,r av flexible anode, said portionsconstituting in-y ductance andhaving juxtaposed areas separated by a dielectric and constituting a capacitance for Y introducing a self-contained inductance-capac- V itance oscillatory circuit in the resonator, a cathodeadjacent said grid on theV opposite side thereof from the anode, said grid and anode beingsub-A stantially paralleljtc each other a smallv distance apartcompared to the wave-length ofA the V.high frequency oscillations, means exterior of theresonator body for adjusting the anode-grid spacing Whilemaintaining evacuation of said char'nber,`

Y and means for deriving high frequency oscillating energy from the resonator body.I Y

10. A hollow-body resonator yproviding an evacuated `chamber for high .frequency oscillations comprising a,metallicright-cylinder portion and a metallic reentrant portion, one of said portions i providing a grid and the other portion providing l an anode, said anode comprising a'resilient flexible diaphragm, a cover member over said diaphragrn, said cover member and diaphragm form. ing a double end closure for said right-cylinder portion, screw means for flexing saiddiaphragm inward of 'said chamber toward the grid, said grid Y and anode diaphragm being substantially parallel to each other a small distanceapart com- Y pared to the Wave-length of the high frequency oscillations, a cathode adjacent said grid on the opposite side thereof from the anode, leads for said anode and grid connected electrically thereto by connection at the outside 0f the resonator body to the respective right-cylinder and reentrant portions, and means for deriving high frequency oscillating energy from the resonator body.V i Y Y Y Y y ILIA EMMANUEL MOUROMTSEEF.` GEORGE MICHAELDINNICK.

evac-

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