Nov. 19, 1946. D. H. SLQAN 2;411;'299 HIGH FREQUENCY TRIODE OSCILLATOR' Filed Nov. 12', 1941 s Sheets-Sheet 1 8O 57 as '87 _ 2 1775-1 INVENTOR. DA v10 H. SLOA N 38 ‘ ‘ A TTORNEYS. Nov. 19, 1946. 2,411,299 D. H. SLOAN HIGH FREQUENCY TRIODE OSCILLATOR Filed Noxul. 1941 6 Sheets-Sheet 2 y FIE-,7 INVEN TOR. DA v10 H. 81. OA-N BY , . ‘ W?’ Z‘. ATTORNEYS. Nov. 19, 1946. ' D. H. SLOAN » ' I 2,411,299 HIGH FREQUENCY TRIODE OSCILLATOR Filed Nov. 12, 1941 6 Sheets-Sheet 3 Em I34, INVENTOR DA VID h’. SLMN BY ‘JEQ’W ogffw ATTORNEYS. Nov. 19, 1946. D. H. sLoAN 2,411,299 HIGH FREQUENCY TRIODE OSCILLATOR Filed Nov. 12, 1941 151"5-593 2 _ 6 Sheets-Sheet 4: I F1“5-11 ~ Lona Ac //6 >30 90 r1 : .98 INPUT INVENTOR. Dawn H. SLonlv Nov. 19, 1946. D H, mm 2,411,299 HIGH FREQUENCY TRIODE OSCILLATOR Filed NOV. 12, 1941 6 Sheets-Sheet 5 227 6/ 2/4 ‘ 206 /6 zrr ,9 .FJ"Eli; za‘: 0 209 8 2IO 212 2H IN VEN TOR.. 0n v10 h’. JLOAN BY. “WM A TTORNEYS. NOV. 19, 1946. D. H_ SLQAN 2,411,299 ‘ HIGH FREQUENCY TRIODE OSCILLATOR Filed Nov. 12, 1941 7 Sheets-Sheet 6 / 1/1, Dav/0 H. 81.04” f PM? W} ATTORNEYS. Patented Nov. 19, 1946 2,411,299 If lTED STATES PATENT OFFICE 2,411,299 HIGH-FREQUENCY TRIODE OSCILLATOR David H. Sloan, Berkeley, Calif., assignor to Research Corporation, New York, N. Y., a cor poration of New York 1 Application November 12, 1941, Serial No. 418,669 36 Claims. (Cl. 250-36) My invention relates to electronic tubes of the triode type and more particularly to high power tubes peculiarly adapted to the production of ultra-high-frequency oscillations, i. e., oscilla_ tions having wavelengths from 10 to 20 centi meters for example. rI'his application is a con tinuation-in-part of my prior application Serial No. 364,284, ?led November 4, 1940. 2 wherein the cooling system does not introduce material parasitic radiation of radio-frequency power; to provide a novel and effective tuning apparatus for a micro-wave oscillation genera tor; to provide a type of electrode support for high-frequency electronic devices which is mas sive and rugged, and whichv at the same time does not introduce inter-electrode capacities In the recent progress of electronic and radio which could either severely limit ‘the frequencies development there has been an increasing de 10 upon which the device is operative or the power mand for oscillation generators combining high power output with micro-wave oscillation gen eration. These two requirements have been, to a certain extent at least, incompatible, and a large amount of research has taken place to the end that these two factors might be reconciled in order to produce practical apparatus which will have a high-power output at extremely short wavelengths. In my previous application cited above I have shown, described and claimed a tetrode structure which is capable of producing many kilowatts of which may be developed at such frequencies; to provide a means and method of easily checking and measuring the power output of high power tubes operating at relatively high frequencies; , to provide a novel means and method of operat ing a high-frequency oscillation generator of the triode type; to provide a simple system of reso nator chokes for use in preventing undesired ra diation from a self-resonating oscillating triode; to provide a means and method of operating a, triode to obtain maximum power output at high frequencies; to provide a simple electronic tube incorporating a resonator, which can be operated as an oscillation generator; to provide a tuned power at wavelengths within the micro-wave range. My present invention is a simpli?ed im provement on the tube of that application, in 25 ?lament tuned-anode oscillator operating with that I have been able to produce a triode tube capacity feedback; to provide a triode oscillator operating on a half-cycle work period, or multiple thereof; and to provide an electronic triode of oscillation power having a l5-centimeter wave length can be produced with the preferred form 30 rugged and simple construction which, when en ergized, can be utilized to produce tens of kilo of tube of my invention, herein to be described, watts of power at relatively high frequencies and using a 60,000-volt anode excitation. short wavelengths, such as, for example, from It is the broad purpose, therefore, of my pres 10 to 20 centimeters. . ent invention to provide a simple, compact and My invention possesses numerous other ob easily assembled electronic tube structure of the jects and features of advantage, some of which, triode type, completely reconciling the apparent together with the foregoing, will be set forth in incompatible factors of the production of large the following description of specific apparatus amounts of power at relatively high frequencies. embodying and utilizing my. novel method. It As a result of this general purpose, therefore, several objects of my invention are: To provide 40 is therefore to be understood that my method is applicable to other apparatus, and that I do not a triode tube which is capable of producing tens limit myself in any way to the apparatus of the of kilowatts of power at extremely high frequen present application, as I may adopt various other cies; to provide a high-frequency oscillation gen erator of great frequency stability; to produce a apparatus embodiments, utilizing the method high-frequency oscillator tube of relatively high 41.5 within the scope of the appended claims. e?iclency, and particularly to produce such a The triode tube of my present invention em bodies several basic concepts. tube wherein the losses due to undesired radia tion from the tube itself are reduced to negligible The ?rst basic concept is the provision of a proportions; to provide a novel means and meth simple resonator having spaced opposing walls od of terminating a resonator or transmission 50 carrying a D.-C. diiference of potential, and line; to provide a high-frequency oscillation gen wherein the cathode is attached to one wall with erator of relatively large physical size, as com .the opposing wall acting as an anode. Grid sur pared to the wavelength of oscillation; to provide faces are inserted between cathode and anode‘ an electronic triode tube of the character de for controlling the effect of the A.-C‘. and D.-C. scribed which may be fully ?uid cooled, and ?elds on the electrons. The grid surfaces may capable of generating a large amount of high frequency power. For example, 100 kilowatts of 2,411,299. 4 be extended to separate the resonator into two resonant regions, if desired. A. second basic concept of my invention is the arrangement and tuning of separate resonator compartments, if used, in such a manner that the tioned therein. Near the outer end of the sup port It the coaxial ducts ‘are separated into re- . ?exed portions I2, ?exible to permit axial expan; sion of ?laments to be attached to the inner end of support III. At the inner end of the central cathode sup port I0, is fastened a circular ?lament support ?ange I4 in which the ducts in support I6 and pipe I I are connected. A cathode resonator end oscillate positively with respect to the cathode 10 element I5 is mounted on ?ange I4 to extend at the same time. If only a single resonator is axially beyond ?ange I4. used, the electrode voltages are divided to cause concentrically positioned around central ?la the tube to oscillate in a similar manner. - I pre ment ‘support I6 is an outer ?lament support I6, fer to use a ?nite transit time, i. e., an electron the two supports I0 and I6 being outwardly pro work cycle of one or more half cycles, preferably 15. vided with lateral sealing ?anges l1 and I9, re tube can oscillate in a tuned-?lament, tuned- - anode circuit with capacity feedback, with or without the aid of electromagnetic feedback. The circuits are tuned so that the grid and anode a single half cycle. . spectively, connected by an insulating cylinder It is practical to make the tube of my inven tion of relatively large size even- for very short wavelengths, as the transit distance may be one 20, such as a glass cylinder, the latter holding the supports in concentric relation, using metal to-glass seals. Sealing ?ange I‘! is attached to eighth wavelength. Thus, in a. tube operating at 20 support I0 outside of reflexed portions l2. De 16 centimeters, for example, the spacing between mountable seals can, of course, be used in con grid and anode surfaces may be approximately junction with continuous pumping. The inner end of outer cathode support I6 is provided with The third basic concept comprises forming elec a circular ?lament support ?ange 2|, positioned trodes of sturdy coaxial metal containers, which 25 parallel to and axially spaced from ?lament sup 2 centimeters. ' form a radio-frequency resonator, or resonators, full D.-C. insulation being maintained between these elements. D.-C. insulation demands gaps, through which radiation is reduced to a negligi ble factor by a choke system formed by a se 30 quence of anti-resonant high impedances and quarterwave low impedance lines. port ?ange I4. _ The cathode support I6 is preferably formed of two telescoping tubes I6 and II, the inner tube I'I having opposite channels I8 cut therein. These channels I8 are connected in support ?ange 2I at one end thereof and to inlet and outlet pipes I9 and 26 at the opposite end, as shown in Figs. 3 and 4, these pipes passing laterally, then out In the ensuing speci?cation, my invention will‘ ' be described in its various aspects as applied to wardly through sealing ?ange I9 and sealed there an oscillator tube of high power, i. e., approxi 35 to at right angles to loops I2. Thus, both ?lament mately 100 kilowatts peak output at 15 centi- ' support ?anges I4 and 2I can be cooled from out meters wavelength, together with the operating side the tube by a circulating ?uid, such as water. circuits therefor, including a simple and emcient Inner and outer cathode supports are spaced by means of measuring the power output of the tube. quartz positioning pins 22 between ?lament sup 40 port ?anges I4 and 2|. The space between ?anges In the drawings: Fig. 1 is a longitudinal sectional view of one - l4 and 2I is closed by extensions 23 and 24 ex form of my invention embodying outside tuning, tending from central cathode support I6 and together with a circuit diagram energizing the ?ange 2I, respectively, and overlapping in the tube to act as a push-pull oscillator. Fig. 2 is a sectional view taken as indicated by the line 2-2 of Fig. 1. ' Fig. 3 is a sectional view taken as indicated by the line 3_—-3 of Fig. 1. ' midplane intersecting the ?laments, without touching. The quartz pins 22 are attached to ex tension 23, and extension 24 is apertured to allow pins 22 to contact cathode support I0. _ Filament ?anges I4 and 2I are joined by a plu rality, preferably twelve in the present instance, Fig. 4 is a sectional view taken as indicated ‘ 50 of U-shaped, axially extending ?laments 25, these by the line 4—4 of Fig. 1. - ?laments being provided with ?at or slightly con Fig. dis an enlarged showing of variable elec cave surfaces facing outwardly, as has been de tromagnetic feedback structure usable in the tube scribed in my prior application cited above. The of Fig. 1. ?laments are preferably of heavy tungsten and Fig. 6 is a partial view showing a ?xed elec tromagnetic feedback usable in the tube of Fig. 1. 55 are arranged to have the outer surfaces thereof Fig. 7 is a diagram showing how the tube of 1 describe a cylindrical surface. Between central cathode support Ill and outer cathode support I6 my invention can operate with all but the elec are positioned a pair of ?lament supply chokes 26 tron interaction ?eld determining elements re and 21, preferably mounted on support III, the ac moved from the grid. — Fig. 8 is a sectional view taken as indicated 60 tion of which will later be described in conjunc tion with the, action of other, and somewhat simi by the line 8-8 in Fig. 7. lar chokes used in the tube. Figs. 9, 10 and 11 are diagrammatic views A grid cylinder 36 is provided, enclosing outer showing modi?cations of resonator choke sys cathode support I6 and cathode resonator ele tems. 4 Fig. 12 is a sectional view of a means of meas 65 ment I5, and spaced therefrom by the use of an outer grid'seal ?ange 3| joined to the cathode’ uring the power output of the tube of my inven seal ?ange I9 by an insulating glass sleeve 32, tion.‘ ' using Inetal-to-glass seals. Here again demount Fig. 13 is a sectional view taken as indicated able seals may be used, if desired. Grid cylinder by line 'I3—I3 in Fig. 12. Fig. 14 is a partially diagrammatic sectional 70 36 is provided ith an inner end 33 spaced from and surrounding cathode resonator element I5. view of a modi?cation ofmy- invention. The grid cylinder is also provided with slots 35 . Referring directly to Fig. 1’ for a-detailed de milled therethrough opposite each ?lament 25. scription of my invention, a ?lament support Other grid constructions providing equivalent structure is utilized comprising a central cathode ' support I6 having an inner cooling pipe II posi 75 electron interaction ?eld control may be utilized 2,411,299 and are deemed full equivalents. ‘The outer por tion of the grid 30 and its sealing ?ange 3| and Consequently, the position of the end plate and therefore the position of the connected chokes 46 and 41 can readily be adjusted. I prefer to hereafter refer to the ends of the resonators in which the choke systems are posi the portion of the cathode support ?ange IS, in side of insulator 20 may be apertured for vacuum communication through the tube. The ?at or slightly concave surfaces of the ?la ments 25 are preferably positioned a few thou sandths of an inch back of the slots in the grid tioned as the closed or short circuited ends there. of, as the ?rst-high impedance choke in each choke system acts as a part of the resonator ‘ which when thus augmented, is really short cir 10 cuited to R.-F. at this extreme end. The ends of the resonators opposite the closed ends I prefer to call the open or open-circuited ends of the resonators, as the resonator spaces are there continuous over the ends of the resona~ cylinder to permit inserting the ?lament group in side of the grid. The grid slots 35 are properly shaped and positioned to distribute the ?eld as uniformly as practical over the cathode surfaces at the time of maximum emission, and to direct these ?elds then toward the anode, with the dis tance from the emitting surfaces to the sensibly always uniform ?eld beyond the grid only a small fraction of the anode-cathode distance. tor conductors and the conductors are electrically open-circuited at this extreme end The cathode resonator is projected by cathode , An anode 31 is provided, also a cylinder having resonator element l5 and grid-end 33, to termi a domed end 38, and is positioned around the grid, nate at their open end, and likewise the anode although in this case the outer end of the anode 20 resonator is continued to an open end termina terminates a substantial distance away from the tion by the portion of the grid extending around grid seal ?ange 3| in‘order to provide space in cathode resonator element l5, and the end 38 sulation. An outer anode seal ?ange 40 is pro of the anode. Thus, the two resonators have a vided, joined with metal-to-glass seals to the grid ‘ .common wall, i. e., the grid. The completed ?ange 3| by an exterior relatively long high-volt resonators are both designed to resonate at the age insulating sleeve 4|, or, if desired, with a de same odd number of quarter wavelengths, pref mountable seal. The tube may be continuously erably ?ve in the tube being described, with a exhausted through a vacuum line attached to the particular ?lament and grid slot location, as will grounded anode of Fig. l or through a sealed 01f glass connection 42 if the tube is to be used as a 30 ’ sealed tube. The anode is provided with a narrow space , water jacket 43 surrounding the impact area of ' be brought out later. , The output of the tube is preferably taken through an output transmission line 6| inserted through anode 31 at a current loop. The output line 6| has a central conductor 62 extending as electrons coming from the ?laments after passing through the grid slots 35. This water jacket is 35 a loop into the anode-grid space and then re turning to contact the outer conductor of the provided with triple inlets 44, and opposite triple line. This transmission line may then be used, outlets 45, so that water may be passed around the as is well known in the art, to supply any load anode at high velocity to effectively cool the an as maybe desirable. The line may be sealed ode. from the atmosphere by an insulating barrier 63 Cathode resonator chokes 46 and 41 are posi tioned serially on outer cathode support l6, and anode resonator chokes 48 and 49 are ‘positioned serially on grid 30, to terminate the cathode and anodes in a high impedance, as will later be ex plained, with full D.-C. insulation between cath ode, grid, and anode. Cathode supply chokes 26 and 21, cathode resonator chokes 46 and 41, and anode resonator chokes 48 and 49 are all anti resonant systems with the two chokes of each sys~ I tem joined by quarterwave line sections. Each comprises, in the tube of Fig. 1, laterally extended ?anges 5| attached centrally to the sup porting electrode, carrying outer cylindrical por~ tions 50 spaced from, but positioned close to and concentric with, the wall of the opposing elec trade. The positioning and function of these 40 positioned at a voltage node. Inasmuch as one of the main uses for a tube of this type is for the production of maximum quantities of oscillating power at low wavelengths, the anode may be energized without external recti?ers, using raw A.-C. I have shown in Fig. 1 one circuit by which the tube has been success fully operated as a self-rectifying oscillator. A ?lament transformer 80 is provided, the secondary 8| of which is attached" to central cathode support H1 and to cathode ?ange | 9. Transformer B0 is excited through a primary 82 supplied from the A.-C. main 83. A.-C. mains also supply a high voltage anode transformer 85 through primary 86, the secondary 81 having one end connected to the anode ?ange 40 and thus to the anode 31. The anode end of the anode chokes will later be described in detail. . transformer is grounded, the anode operating at I may ‘prefer to make the cathode resonator ground D.-C. potential, providing a grounded choke systems 46 and 41 movable for tuning purposes, and therefore mount both of these 60 anode tube in this embodiment of my invention. The other end of the anode transformer second chokes On a sleeve 52 sliding on outer ?lament ary 81 is connected through a resistor 89 to one support It‘, the inner end of this sleeve terminat side of the cathode, such as, for example, ?ange il'lg in the same plane as the'inner end of the I9. Grid bias for ?eld control is obtained‘ by a cylindrical portion of choke 46. The two chokes joined - by this sleeve may be axially moved by 65 connection 90 on the grid ?ange 3| to some point on the resistor 89 as may be found desirable. a rod 53 extending axially along the space be This bias may be from 100-3000 volts negative, ' tween the outer ?lament support l6 and ‘the grid on the operative portion of the supply cycle. 30, and then bending outwardly to pass axially Before passing to the geometry of the resona again through an opening 54 in the cathode seal ?ange [9. The rod is fastened to an end plate 55 70 tors, a discussion of the means and. method by which I effectively close the resonators to R.-F. attached to cathode ?ange Is by a metal bellows with full D.-C. space insulation is ?rst in order. seal 56, the position of end plate 55 being regu As a ?rst premise, the outer ends of the ?lament lated by end plate positioning screws 51. The supports, grid and anode, can be considered as vacuum within the tube tends to collapse the bellows, and the screws prevent this collapse. 75 antennae, ready and willing to radiate if energy escapes to those ends. Such radiation may be 2,411,299 taken to be a loss load, and should be reduced to a negligible factor. For purposes of discus sion, therefore, the outer portions of the chokes or choke systems can be spoken of as the load ends thereof, and the‘ inner portions as the input ends thereof. Before discussing the physical shape the choke systems may assume, as these shapes may be Movement of the position of the choke-line choke system for the purpose of tuning may be considered as varying the amount of conductor existing in the resonant line up to the point where it is cut for insertion of the low impedance of viewpoint one, or cut for high impedance ter mination of viewpoint two. The voltage across the input choke is as high as the standing wave voltage at the end 01' the several, the operation and theory of the choke systems will be brie?y set forth. The problem is, 10 last quarterwave section of the line, and the anti resonant impedances are similar. Therefore, of course, to terminate the transmission lines, the energy stored in the choke is as great as the as the anode and cathode resonators are true energy in the adJacent quarterwave section of transmission lines, without substantial loss of line to be terminated.- Thus, the input choke energy past the terminations, meanwhile main taining complete D.-C. insulation between the‘ 15 adds an effective quarter-wavelength to the sys - tem of standing waves in the line. As the stand walls of the lines or resonators. ing wave loop appears at the end of the line Obviously, a transmission line can be termi the position of the choke system along the line nated by a conductive barrier connecting the in can be used to tune the line. ‘ ner and outer conductors, thus providing zero In the second view, one conductor of the reso impedance across the line. Such a barrier would 20 nant line is provided with a physical out which not, of course, permit any D.-C. di?erence of is bridged by a quarter wave anti-resonant potential between the line conductors in this ?rst choke, with the provision of a second out at the method. end of an electrical quarter wave continuation of A second type of termination would be a ter mination of in?nite impedance, such as if a line 25 either of the line conductors toward the load and the provision of a similar choke bridging the conductor were to be completely cut off at the second cut. Thus, the intermediate quarter desired point.‘ However, such a cut-off would wave line section terminates in a high impedance prevent support between the cut-off portions and making the input to this quarter wave line have prevent metallic connection to maintain a D.-C. very low impedance. This very low impedance potential. 30 appears in series with the high impedance of the My preferred and practical method of reso nator, combines the D.-C. insulation, D.-C. con nection, and physical support. It will be de ?rst quarter wave choke, and both impedances are connected directly across the end of the line which is to ‘be effectively opened. The high im described as an alteration of type two. Both 35 pedance limits the current which can ?ow scribed as an alteration of type one, and then viewpoints are essential. Viewed as a modi?cation of the ?rst or short through the low impedance hence very little power enters the low impedance line to escape from the resonator. The input side .of the line circuited termination for preventing the escape leading to such a choke system is now effectively of radiation, the conductors are metallically joined, and D.‘-C. insulation is provided by cut 40 terminated by a nearly in?nite impedance, and only a standing wave voltage 100p can appear at ting open one conductor of the line at a current the end of the line. Thus, from the second view node and bridging this cut by a very low im point, I have provided a practical equivalent of pedance which is formed by the input end of a a physical open circuited end of the input line, quarterwave line whose distant open “load” end terminates in a high impedance. ‘Almost negli 45 meanwhile maintaining D.-C. connection, full support of the conductors, and D.-C. insulation gible power will ?ow into this line because between line conductors. negligible current ?ows through its almost neg While there are a large number of physical ligible input impedance. This low impedance is structures which will provide a choke system op made of two insulated conductors forming the as above described, I ?rst wish to describe quarterwave line, thereby providing D.-C. in 50 erating a toroidal form of choke system, inasmuch as this sulation where the low impedance is connected type of choke system clearly illustrates successive into one of the resonator conductors. This con nection occurs one quarter wavelength away from conductor separations, these separations being joined by solid choke members. . the short circuit that suggested the name “closed” Referring, therefore, first to Fig. 9, a trans 55 mission line having closely spaced inner and for this end of the resonator. The second viewpoint considers the resonator outer conductors190 and 9| having an input end line terminating in an open circuit at the same 92 and a load end 93, is diagrammatically illus point where it was cut to insert the low im trated with the chokes positioned inside the in pedance quarterwave line connection of the ?rst ner conductor, although either conductor may be method. The quarterwave section beyond this 60 used. Toward the input end, the inner conductor cut is now considered asa choke in series with the low impedance quarterwave line, and together is physically cut to provide a gap 94. The two ’ physically cut ends of the line are then joined they act as the high impedance termination of by a toroidal, anti-resonant high impedance in the resonator which now ends at the cut and is put choke 95. a quarterwave shorter than the resonator in the 65 On the load side of the high impedance input ?rst viewpoint. Thus the short-circuited end choke, the inner conductor is continued as an section of the resonator beyond the cut may be electrical quarter wave line section ending at a considered as part of the resonator in the ?rst second gap 96 in the conductor which is bridged view or as the ?rst choke in the high impedance by a second toroidal choke 91 similar to the ?rst. termination of the second view. Its variation of 70 Full physical support, therefore, is given to the impedance with frequency makes it important input end of the inner conductor from the load in the tuning of the resonator. Subsequent de end through the chokes, with loss toward the load scriptions will follow this second viewpoint, hav end reduced to a negligible factor and with the~ ing the open circuited line terminated by a choke complete D.-C. insulation between the line mem 76 bers, as above described. line-choke combination. 2,411,299 10 While such toroidal chokes may be used in conjunction with the tubes herein described, resistance of the support is greatly lowered, with a consequent gain in ei?ciency. Under these cir cumstances, the section of line of increased diameter would be followed by the choke~line choke system 46-51‘ to terminate the line, as has previously been described. A second gain is also accomplished, in that the voltage to the input where room for insertion is available, such as extending outwardly from the anode for example, I may prefer to utilize other and fully equivalent forms of choke systems, particularly if tuning of the associated resonators is desired, as by moving the choke systems along the line. ‘ choke 46 is now muchlower, and the losses in this choke are thereby reduced. resonator terminal systems. In these, the cross 10 However, the increase in diameter of support section of the concentric lines is changed by ad Ill may be su?icient to permit the interior of ditional conductors supported by a continuation the enlarged portion to be used as the input of one of the conductors, this continuation no choke by removing the rear wall 99 of the en longer forming a part of the standing wave area larged portion 98 to provide a choke loll opening of the line. The line formed by the additional toward the load, as shown in Fig. 11. The second conductors may then be cut and the cuts bridged orload choke ml is then reversed for symmetry _ by chokes, as hereinafter described. These sys and for ease of establishing the required quarter tems are used to terminate the cathode and anode wave line section I I12 between the chokes. The resonators of the tube heretofore described. anode chokes Hi3 and I04 may also be reversed, In Figs. 1, 10, and 11, I have shown different 20 with comparable results. The mode of operation forms of cylindrical choke systems, each com In Figs. 1, 10, and 11, I have shown equivalent of the tube in any case is the same, and full D.-C. prising two anti-resonant chokes, spaced by quarter wave transmission lines. In Fig. 1, the cathode choke system 46-41 is shown movable and with the separate chokes opening toward the ?laments, While the anode choke system 48-49 is shown ?xed in position and opened in the same direction. In Fig. 11, all of the chokes are shown ?xed in position but opening away from the ?laments. Fig. 10 shows an interme 30 diate step. First, I wish to discuss the type of choke sys tem shown in Fig. l where the chokes open into the associated resonator'spaces, either as movi able or ?xed systems. In case a ?xed choke sys tem is desired, the choke ?ange 5| of each choke may be rigidly attached to the supporting ele insulation is maintained, with the desired high impedance line termination accomplished. Before passing to the discussion of the oper ation of the tube, it will be desirable to discuss the geometry of the resonators with relation to the ?laments. The anode resonator may be di— mensioned to be exactly ?ve quarter wave lengths long. Thus, when this resonator is prop erly energized, there will be standing waves pro duced on the walls thereof. The ?laments, grid slots, electron path, and the anode impact area are all positioned to straddle a standing wave voltage loop, with the region of maximum volt age approximately in the plane at a right angle to the axis of the tube dividing the ?laments in half. Thus, there will be half of the axial extent ment by welding, silver soldering, brazing, etc., of the ?laments on one side of the standing wave at a current loop. The free edges of the cylin loop peak, and the other half on the other side of this loop peak, thus placing peak voltages in the region of maximum ?lament emission. A preferred relationship is to make the ?laments extend axially somewhat less than a ‘quarter drical portions areat voltage loops. When ?xed chokes are used, the connection of the ?ange to its supporting element at a current loop is not a disadvantage as conduction between ?ange and supporting member will be good. wavelength. When a, movable system, however, such as sys 45 The ?lament and the grid slots may have their tem 46-41 in Fig. 1 is utilized, if no sleeve 52 midpoints located one or more half electrical were to be utilized, there would be a high current wavelengths distance away from the open end of density and high resistance between the sliding the resonator to obtain fairly accurate registra contact of the ?ange 5| and the supporting member, particularly at the ?ange closest to the 50 tion of the peak of the standing wave voltage loop with the central plane of the ?laments. I / resonator space. However, when sleeve 52 is prefer, however, that the central plane of the ?la used and the sleeve extended along the support ments be a single half Wavelength away from the ing member to terminate at the same level as the open ends of the resonators. Thus, in the de free edge of the cylindrical portion, the free end of the sleeve is at a current node and the re 55 scribed tube the central plane of the ?laments will'be one electrical one-half wavelength away sistance losses are low. from the open ends of the resonators and three It will be noticed that, when this type of choke electrical quarter wavelengths away from the system is utilized, there may be, in an extremely closed ends of the resonators, as it will be re high powered tube where the inner conductor of membered that the choke system adds one quar a line resonator is of small diameter compared ter wavelength to the closed end of each res to the diameter of the outer conductor, high onator. I densities on the inner conductor, as for example I prefer to utilize the single half wavelength the outer ?lament support In in the tube of Fig. 1. spacing of the ?laments from the open ends of The current has to pass along this support to the resonators, because under these conditions reach the ?ange 50 of the input choke. In order 65 the tube cannot easily operate at any lower fre to reduce this high current density, it may be quency than the desired frequency. The only other frequency at which the tube might readily oscillate, with the central plane of the ?laments desirable to effectively enlarge the diameter of the support I!) at positions of heavy current con centration. a single half wavelength away from the open 70 ends, would be a double frequency. However, as complished, for example, by increasing the size a practical matter, the possibility of such oper of a quarter wave section of the support II] with ation is remote unless the anode voltage were to a closed end cylinder 98 until the exterior surface be properly increased to give the proper electrode thereof approaches the grid 30, as shown dia work period for the higher frequency. This effective increase in diameter can be ac grammatically in Fig. 10. When this is done, the 75 The open resonator ends are also important in 2,411,999 11 I that they establish symmetry for the tube, pre vent parasitic oscillations, and stabilize the standing wave patterns axially along the res onators and consequently over the ?laments and grid slots with equal voltages in planes at right angles to the axis of the tube. Tuning of the ?lament resonator by move ment of the grid choke system is such as to tune this resonator to provide a low inductive re - 12 the coupling and still. maintain a ?xed phase angle of nearly 180° between anode and cathode voltages, then electromagnetic coupling between cathode and anode resonators may be resorted to. In case it may be found desirable to use electro magnetic feedback between the anode resonators and the grid resonators t6 increase coupling, I may desire to provide a variable feedback in the form of a coupling loop I00, as shown in Fig. 5, 10 this coupling loop being attached to a coupling actance. transmission line Ill extending laterally from If the circuit thus presented be analyzed, a the anode 31 preferably at a voltage node, the tuned-?lament, tuned-anode circuit is provided, central conductor N2 of the coupling transmis with the anode and the cathode resonators sion line 56 extending through the space between coupled only by the anode-cathode capacity and with the grid as an untuned D.-C. biased struc 15 the grid and anode, through an aperture H3 in the grid 30, and then returning through this same ture ?oating at R.-F. potentials induced in it by aperture to contact the outer conductor of the the ?elds in the anode and cathode resonators. line. The coupling loop is tuned by providing a If, as in the structure shown, the ?lament cir conductive closure I H to the transmission line, cuit is made to have an inductive reactance small in relation to the capacitative reactance between 20 this closure being movable along the central con ductor through the medium of a bellows H5 and anode and cathode, we have a condition set up adjusted by screws “6 as to position along the where the R.-F. grid and anode voltages, with line. . respect to the cathode, are in phase with re The standing wave pattern on coupling line spect to each other when the anode voltage is adjusted to operate the tube on an R.-F. half 25 I l I can thus be varied by varying the position of closure Ill and any desired amount of feedback ' .cycle electron work period, or by proper phas passed through the loop llll. ing of voltages with a work period of a multiple If, however, only a ?xed electromagnetic feed of half-cycles, although a single half-cycle work back is needed, the device shown in Fig. 6 may period is preferred. This work period is not nec essarily the actual electron transit time,'but may 30 be used. Here the opening “3 is provided in grid 30 with a ?xed loop ll‘! attached to one side be more truthfully considered as the period of this opening and entering both grid-cathode ‘ elapsing between the time of maximum emis and grid-anode spaces. The size of the coupling‘ sion from the ?laments and the time of max loop willdetermine the amount of feedback. imum work performed by the emitted electrons It will be seen from the foregoing description on the load ?eld. With a half-cycle R.-F. work 35 that the modi?cation of the tube of my invention period and with the reactances properly relat just described embodies two resonators having a ed, the ?laments will be negative when both grid common wall, 1. e., the grid, and that the grid and anode are positive. For the next half-cycle slots are positioned in this common wall with the this condition will be reversed, so that both grid and anode will be negative when the ?laments 40 ?lament as a part of a facing wall. It will also be clearly seen that the operation of the tube as are positive. Under these conditions, therefore, an oscillator relies upon the establishment of a and under this mode of operation, there will be standing wave pattern in boththe anode reso extremely high emissions take place from the nator and the cathode resonator. It follows, negative ?laments when the grid and anode are simultaneously positive, and e?icient electron 45 therefore, that the standing waves on the grid wall facing the cathode elements are actually cut-offs when .the grid and anode portions are closely alike and may, in some instances, be actu both negative with the ?laments positive. ally alike and register both as to position and The anode in the present tube and circuit op strength, with the pattern on the grid wall facing erating in the manner described, therefore, has the anode. When such registry occurs, there is the novel function of effectively performing in the same manner as an accelerator grid in a no need for the grid surfaces-other than the ?eld tetrode, only however when accelerations are de determining portions of the grid closely adjacent sired. the ?laments. When such registry occurs, all portions of the grid may be removed, except those Furthermore, this acceleration function diminishes or disappears during the interval when accelerations are‘ not wanted. Thus, both 55 portions immediately adjacent the ?laments, to allow the identical resonator ?elds to merge. anode and grid cooperate in starting and pre If, for example, we call those portions of the venting electron emission. Extremely large grid 30 adjacent the ?laments utilized for the amounts of oscillating power are thus produced. Feedback is entirely capacitative. Consider concentration of the anode ?eld on the ?laments the anode and ?lament voltages with respect to 60 25, the control surfaces, and if we call the re: the grid voltage. The present ?lament and its support system‘ is completely shielded from the anode by the grid, except at the grid slots. The ?lament voltage need not be 180” out-of-phase maining material of the grid 30 the shielding surfaces, we can see that the presence of the shielding surfaces between the cathode structure and the anode is only useful in case the standing with the anode voltage,‘ as would be the case 65 wave patterns are unlike in strength and position on each side thereof. When the ?eld strengths were a skeleton grid to be inserted between the are alike all along the resonators, the shielding ?lament and anode, as will later be described. surfaces can be completely removed and the tube Instead, the ?lament voltage may be given almost will operate exactly as if such surfaces were pres any phase angle between zero and 180° with re spect to the anode voltage, by a suitable choice 70 ent with only a slight change in basic frequency. However, even if the standing waves along the of the grid-?lament impedance, which is in series resonators are not alike, if the standing wave with the ?lament-anode capacitative reactance conditions in the neighborhood of the ?laments and driven by the voltage between the grid and are alike, then the grid shielding surfaces can be anode. If, however, it may be felt desirable to increase removed and the tube will still oscillate, although 13 2,411,299 under these conditions there will be a more sub stantial change in frequency. The removal of the shielding grid surfaces can be accomplished by the‘ provision of a skeleton grid, this grid being designed to give the proper ratio of capacity between grid and the anode and the grid and the cathode. The grid under these ' 14 cathode as to distribute this ?eld on the ?laments by virtue of the D.-C. bias placed on the grid. The second function of the grid is to permit, in the ?rst embodiment shown, the standing wave ?elds to be unlike in strength inside and outside the grid conductor, and to permit them to be deliberately made unlike by tuning to adjust 4-f. conditions may be considered as an intermediate voltage relationships. If the standing waves are, point between two condensers, and the grid may be shaped to divide the voltage in a. proper ratio 10 however, alike and registered even though only in the neighborhood of the grids, the shielding with the anode voltage nearly 180° out~of-phase portions of the grid can be removed without af~ with the cathode voltage. Obviously, this ca fecting the oscillation of the tube in any manner, pacity ratio will be different for different tubes provided the biasing ?eld remains. Even though and is ?xed for a given set of conditions. slightly unlike, the voltages can be adjusted by The main difference, therefore, between the use 15 proper grid skeleton disposition. of the grid-shielding surfaces and the omission I would like to point out, however, that the thereof, is that when the grid-shielding surfaces particular means of supporting the grid structure, are used, the cathode and anode circuits are shown in the tube of Fig. 7, is only a. preferred separated and can be separately tuned, thus mak means. Other equivalent arrangements may be ing the tube more ?exible in operation. However, 20 utilized to support the grid within the tube. I, for any ?xed set of conditions, the grid-shielding would further like to point out that the use of surfaces can be completely removed and the tube parallel grid wires for determining the bias ?eld will still oscillate, with the voltages still divided is also not to be held a limitation, as other types in the proper ratio and phase. In Fig. '7, I have shown such an embodiment 25 of grid structure, such as a cylindrical mesh screen, may be utilized around the ?laments and of my invention. All of the grid surfaces have will perform in an essentially similar manner. been removed except those surfaces which are The main considerations to be taken into account necessary for the application of the D.-C‘. bias in designing a tube of the type shown in Fig. 7, ?eld to distribute the anode ?eld on the ?laments. are that D.-C‘. ?eld determining grid elements In this case, the ?lament supports, the ?lament 30 are to be left within the tube, these grid elements ?anges, the ?laments, and the cathode resonator properly disposed to divide the standing wave element I5 are all made exactly as before. The voltages in the same manner as if the grid anode is ‘as before, but in this case the R.-F. shielding surfaces were to be present. ‘ closure of the single resonator remaining is per Thus, it will be seen that, reduced to its lowest fected by a single quarter wave choke system I30, 35 terms, the tube of my invention as shown and this system being mounted on the outer ?lament described herein is of relatively simple structure, support It. The choke elements extend out and, if desired, can be reduced to the basic form wardly with the cylindrical portions 50 thereof of a single resonator, this resonator acting‘ as a positioned concentric with the anode wall in the coupled cathode and anode resonators. proper position to electrically close to R.-F. the 40 In Figs. 11 and 12, I have shown a modi?cation single physical resonator remaining, at ?ve quar of the tube of my invention as constructed for ter wavelengths with, as before, full D.-C. insula~ tion. The grid has been reduced to a mere skele ton, comprising an outer grid ?ange I3I and an inner grid ?ange I32 joined by parallel grid wires I34 with one of these wires positioned on each side of each ?lament 25 and slightly toward the anode from the ?laments. These wires take the place of the slot edges in the previously described modi?cation. Proper voltage division is provided by the extent of grid ?anges I3I and I32 toward the anode. use in a grounded-grid circuit, and arranged to be continuously pumped by a vacuum connection to the grid. Furthermore, this modi?cation of my invention, as will be more fully pointed out later, utilizes a lateral rather than axial arrange— ment of choke-line-choke elements in the anode grid resonator. Power may be taken out of the tube without reducing the effective anode-grid spacing, thus preventing spark-overs at high anode potentials. It will be noticed in this regard that in the tube of Fig. 1, the effective anode-grid spacing is re I36 in one wall of the resonator. These openings 55 duced by the projection of the inner conductor 62 of the output transmission line into the anode are surrounded by support transmission lines I31 resonator space. This is eliminated in the tube in which are positioned quarter wave choke-line of Figs. 11 and 12. Furthermore, in the tube of choke systems I38 to prevent radiation losses Figs. 11 and 12, electrons discharge through the along the grid arms, exactly as described for the anode and are picked up by the back of the anode, resonators. The grid support arms I35 may be thus preventing the formation of hot-spots on supported by insulating discs positioned beyond the anode wall. In these ?gures, all elements not the outer choke. Thus, the grid bias may be sup new ‘to the arrangement have been given nu plied to the grid skeleton through one or all of merals corresponding to the numerals previously the support arms. used for the same parts. Except for the manner by which the voltages 65 Referring to Figs. 11 and 12 for a more detailed are established, the tube just described will oscil description of this modi?cation of my invention, late in exactly the same mode as the tube pre concentric inner and outer ?lament supports I0 viously described, in exactly the same manner as and I6 are provided, as in the previous embodi if the shielding surfaces of the grid were present. ment, and these supports may be, if desired, water An analysis of this last-mentioned tube will 70 cooled in exactly the same manner as previously show, therefore, that the grids in the tubes and described, except that in this case expansion loops circuit described in this application have two I2 may be dispensed with. ' separate functions. The ?rst important function The ?laments 25 are supported on one end of the grid in both tubes herein described, is to so modify the D.-C. ?eld between anode and 75 thereof by blocks 200 attached to’ the inner ?la The grid skeleton is preferably supported by support arms I35 extending through openings ment support ?ange l4 by a plurality of spaced 7 2,41 1,299 15 16 layers of resilient ?ns 20I, so that the ?laments can expand and contract during heating without exerting pressure between ?lament supports I 0 I prefer to terminate the anode resonator in an inner quarterwave choke and line section A followed by an annular quarterwave line B; a choke C followed by a quarterwave line D; backed up by av quarterwave choke E, line F and ?nal choke G, these lines and chokes beingannularly disposed rather than axially disposed as in the tube of Fig. 1. and‘ I6. ' Due to the resilient ?lament connection, inner and outer ?lament supports can be sealed to gether by the use ‘of spaced annular insulating rings 202 and 203, such as of glass or ceramic, Such a termination of the anode resonator separated by a rubber ring 204. These rings are slidably positioned around the inner ?lament 10 permits the power take-off loop GI to be inserted through the stepped ?ange 220 of the grid at a support I0 and spaced from the ?xed base of the region of maximum current in the ?rst choke outer cathode choke 21 by a short spacing sleeve A, which is also a part of the anode resonator. 205. A long spacing sleeve 206 is then led out 'Thus, the take-off conductor 62 does not pass wardly along support I0 and slidable thereon to contact an outer glass ring 201 spaced from a 15 through the anode wall at any point. The tube is arranged, therefore, so that it can be used in second outer glass ring 208 by a second rubber a grounded grid circuit. Such circuits enable ' ring 209. the tube to be utilized at high powers with signal Pressure is applied to force ?lament support I0 modulation, as for example when large amounts . outwardly, through a glass pressure ring 2I0 out side of the tube, forced against the end of ?la 20 of signal modulated power are desired. I have found that great difficulty has hereto ment support I0 by the usev of screws 2| I threaded fore been experienced in providing a proper and through a connection block 2I2 fastened to the accurate measurement of the absolute power out— inner ?lament support I0. The pressure applied put of high power tubes such as I have described by screws 2I I forces the glass elements of two sets operating at short wavelengths. I have therefore of glass rings together, thus expanding the inter shown in conjunction with the output circuit of mediate rubber rings against ?lament support I0 my tube, a means whereby the total power out and a sealing sleeve 2 I4 inwardly attached to put of the tube may be quickly and easily meas outer ?lament support I6. An e?’ective and vac ured. Fundamentally, I provide a high loss uum tight seal between the inner and outer ?la ment supports I0 and I6 is thus procured, The 30 branch transmission line which may have, for inner and outer cathode supports are ?rmly tied example, a resistive element heated by the power absorbed in the line, with calorimetric measure together and, due to the resilient support of ?la ment of the heat produced. One such means ments 25, ?lament breakage during tube trans for high powers is shown in Fig. 14. For this port is eliminated. The grid proper is shaped and positioned simi 35 purpose I provide a branch transmission line I50 on output transmission line 6|, having a com larly to the grid 30 in the tube of Fig. 1, but in posite normally non-conductive inner element this case grid 30 is supported on a lateral ?ange comprising an outer glass tube I5I and an inner 2 I 5, which in turn is supported by a heavy frame glass tube I52. The branch transmission line 2 I6, this frame being connected to ?lament sup port ?ange I9 by a glass cylinder 2I'I, thus com 40 I50 may be made any odd number of quarter wavelengths, preferably one or ‘three quarter pleting the tie-up between the grid and the ?la- \ wavelengths long, so that when the inner por ment supports. A choke-line-choke system tion is made conductive, the power of the tube 26-21 is provided in the space between the outer output may be absorbed in the transmission line. ?lament support I6 and the grid 30, as in Fig. 1, I preferably make the inner portion of this and the space between ?lament support ?anges branch transmission line resistively conductive I4 and 2| is shorted to R.-F. by quarterwave by circulating brine at a known rate through cylinder 2 I 8. tubes I5I and I52 from a brine inlet I54 to a Attached to the outside of the grid 30 above brine outlet I55, both the brine inlet and brine the lateral ?ange 25, is a second lateral grid ?ange 220 extended outwardly in steps to support 50 outlet being provided with thermocouples I55 and I51, respectively, connected in series. Theavail a cylindrical glass anode insulator 22I, the top able load power of the tube will be dissipated in of which is closed by an anode disc 222, through which pass a plurality of internally looped water heat in the branch line I50, and will show up as a current in meter I58. ‘ As this current dif cooling pipes 224, the ends 224' of these loops ference is a measure of the heat dissipation in being welded to anode cylinder 3'! closed by anode dome 38.v Adjacent pipe loops 224 are connected the branch transmission line, the absolute power output of the tube may be readily calculated, as on one side by anode material, and each con the volume of water heated will be known, and nected pair of loops are spaced so that the spaces come opposite the grid slots and the ?laments. heat losses from the line-to atmosphere can be Thus, the electrons emitted from the ?laments, 60 readily calculated or measured. Such an arrangement need only be used when afterbeing decelerated, pass between adjacent loops of the water cooling pipes into the space checking the power, as the brine may be followed by distilled water to clean the insulated pipes 225 between the anode 31 and the glass cylinder The glass charges up and repels the elec and then removed from these pipes. This will trons,» which are then collected by the outer sur 65 effectively remove the central conductor from face of the anode and the pipes themselves. In the line, and no power will be absorbed. asmuch as the electrons become widely dispersed The length of the branch line is dependent on within this space, no hot-spots can appear on the anode at any point. I Anode potential is supplied to the anode disc 222 through connection 226. Inasmuch as it is ‘desired to operate the grid of this tube at ground the power to be absorbed. It should be of the proper length, if in quarter wave multiples, to transfer all the heat dissipated therein to the brine without boiling the brine. However, if a continuous check of power out- ' potential, a permanent connection of a pumping put is desired, the line may be tuned to absorb only a small predetermined percentage of the line 221 can be made to the grid structure be 75 load, the brine continuously circulated at a known tween ?anges 2 I5 and 220; 17 2,411,299 rate and measured as to heat absorbed. Many variations and combinations of the two methods will be apparent to those skilled in the art. It will also be obvious that the power absorbing line may be attached directly to the tube anode, if desired, and that the dissipated line may use high resistance solid material cooled by non conductive ?uids. I claim: 18 wherein a transmission line is connected to. the outer conductor only, with a, central conductor positioned in said line, entering said outer con dgctor and re?exed to contact the wall of said 1 e. 10. An electron discharge device comprising concentric outer anode and inner grid conductors having adjacent physically open ends and adja cent physically closed ends, a pair of concentric 1. An electron discharge device comprising 10 cathode conductors positioned concentrically three substantially parallel disposed walls form within the grid conductor, one of said cathode ing a pair of resonators having a common wall, conductors being longer than the other, parallel adjacent physically closed ends and adjacent laterally extending ?anges mounted on said cath physically open ends, a radio frequency closure ode conductors, a, plurality of equally spaced cir ‘ mounted on each of two of said walls and ex 15 cumferentially‘ positioned ?laments extending ax tending toward and spaced from the adjacent ially to connect said ?anges, said ?laments be walls to maintain direct current space insula ing positioned adjacent the inner surface oi.’ said tion between said walls, said common wall having grid conductor, said grid conductor having ax an opening therein, and an electron emitting ially extending slots therein registering with the surface on one of said other walls presented and 20 extent of said ?laments, a cathode radio-ire adjacent to said opening, said opening and said quency resonator closure ?ange mounted on said electron emitting surface being positioned to cathode conductors, a concentric skirt mounted straddle a voltage loop between the ends of said on said ?ange and spaced from said grid con resonators. ductor, an anode radio-frequency ‘closure ?ange 2. An electron discharge device comprising 25 mounted on said grid conductor, a concentric three concentric conductors, the two outer con ductors having adjacent spaced physically closed ends and adjacent spaced physically open ends, skirt mounted on said latter ?ange and spaced from said anode conductor, and insulating ele ments joining said cathode conductors, said grid a concentric skirt ?ange-mounted on two of said conductor and said anode conductor outside of conductors, and extending between the inner 30 said ?anges. and intermediate conductors and between the 11. Apparatus in accordance with claim 10 intermediate and outer conductors to terminate wherein said ?laments and slots are positioned said latter conductors as radio-frequency resona to straddle a voltage loop between the physically tors with direct-current space insulation, an elec closed ends of said grid and anode conductors tron emitting surface mounted on said inner and the radio-frequency closure of said physically conductor, said intermediate conductor having an open ends by said ?anges and skirts carried opening adjacent and registering with said elec thereby. tron emitting surface. 12. Apparatus in accordance with claim 10 3. An electron discharge device comprising wherein said ?laments and slots are positioned three concentric conductors, the two outer con to straddle a voltage loop between the physically ductors having adjacent spaced physically closed closed ends of said grid and anode conductors ends and adjacent spaced physically open ends, and the radio-frequency closure of said physi a concentric skirt ?ange-mounted on two of said cally open ends by said ?anges and skirts carried conductors, and extending between the inner and thereby, said voltage loop being one or more half intermediate conductors and between the inter 45 wavelengths away from said physically open ends. mediate and outer conductors to terminate said 13. Apparatus in accordance with claim 10 latter conductors as radio-frequency resonators wherein said ?laments and slots are positioned to with direct current space insulation, a plurality straddle a voltage loop between the physically of axially extending cathodes mounted in con closed ends of said grid and anode conductors centric relation on said inner conductor, said 50 and ‘the radio-frequency closure of said physi intermediate electrode having a plurality of ax cally ‘open ends by said ?anges and skirts car ially extending-slots registering in radial spaced‘ relationship with said ?laments. ried thereby, said voltage loop being one-halt wavelength away from said physically open ends. 4. Apparatus in accordance with claim 3 14. In an oscillator circuit utilizing a triode wherein said inner conductor is concentrically; 55 tube having a cathode completely shielded from divided to provide paths for conductive heating an anode by a single grid except for intermediate of said ?laments. ' grid openings in said grid, means for supplying 5. Apparatus in accordance with claim 3 a D.-C. potential to said cathode with said anode wherein said concentric skirts form quarterwave at ground potential, a tuned cathode circuit, a terminations of said resonators. 60 tuned anode circuit, and a substantially react 6. Apparatus in ~ accordance with claim 3 ance-free grid circuit connected together and to wherein said concentric skirts form quarterwave the respective electrodes, the inductive reactance terminations of said resonators, and wherein each of said cathode circuit being less than the ca of said concentric skirts is outwardly backed by pacitative reactance of the cathode-anode inter additional quarterwave concentric skirts spaced 65 electrode capacity to provide capacity feedback by a quarterwave line section. for self-sustaining oscillations with the grid and '7. Apparatus in accordance with claim 3' anode radio-frequency potentials at least par wherein said slots and said ?laments are posi tially in phase with relation to said cathode. tioned to straddle a voltage loop in said resona 15. An oscillation generation circuit compris tors. 70 ing the tube of claim 10, an ‘anode transformer 8. Apparatus ‘in accordance with claim 3 having a secondary connected to said ?laments wherein said conductors are joined, positioned and to said anode with said anode grounded, a and sealed by connecting insulating-elements out resistance between said transformer and said side of said concentric skirts. ?lament connection; and a, connection between 9. Apparatus in accordance with claim 3 7.5 said grid and said resistor means for heating said 2,411,299 19 20 ?laments to cause electron emission therefrom, ance in the circuit cathode small in relation to the voltage of said anode being controlled to the capacitative reactance between anode and cathode thereby causing said tube to oscillate by the feedback due to anode-cathode capacity only cause said tube to oscillate on a, half-cycle elec tron work period when said radio-frequency clo sures are positioned on their respective electrodes to dimension the coextensive resonators to sub stantially an odd number of quarter wavelengths. 16. An oscillation generation circuit compris ing the tube of claim 10, an anode transformer having a secondary connected to said ?laments 10 and to said anode with said anode grounded, a re sistance between said transformer and said ?lament connection, and a connection between with an electron work period of one or more half cycles. 20. A self-resonating electron discharge triode tube having an inner cathode resonator element and an outer anode resonator element, an elec tron emittin'g section forming a part of said oath ode resonator element, and a, singe ?eld modify ing meansbetween said electron emitting section and said anode resonating element, adjacent said electron emitting section only. said grid and said resistance, means for heating 21. Apparatus in accordance with claim 20 said ?laments to cause electron emission there 15 wherein said resonator elements are substantially from, the voltage of said anode being controlled an odd number of quarter wavelengths long. to cause said tube to oscillate on a half-cycle elec 22. Apparatus in accordance with claim 20 tron work period when said choke ?anges are po wherein said resonator elements are substan sitioned on their respective electrodes to dimen sion the coextensive resonators to substantially 20 tially an odd number of quarter wavelengths long with said electron emitting section axially strad an odd number of quarter wavelengths with the dling a voltage loop position. peak of a voltage loop between the ends of the 23. Apparatus in according with claim 20 coextensive resonators positioned approximately wherein said resonator elements are substantially midway between the ends of said ?laments. 17. An oscillation generation circuit comprising 25 an odd number of quarter wavelengths long with a triode tube having an anode shielded from a said electron emitting section axially straddling cathode by a single grid except for intermediate grid openings in the same grid, a resonant circuit quarter wavelength axial extent. a voltage loop position and of less than one 24. Apparatus in accordance with claim 20 having one end connected to said cathode, a reso nant circuit connected at one end to said anode, 30 wherein said ?eld modifying elements are con ?ned to the immediate neighborhood of said elec the other ends of said circuit being connected to tron emitting part of said cathode resonator ele gether, a substantially reactance-free connection ment and have capacity dividing portions ex from said grid to said connected ends, means for tending toward said anode only. impressing a direct current potential between said 25. Apparatus in accordance with claim 20 cathode and anode with said anode grounded, said 35 wherein said resonator elements are substantially potential being such as to provide a half-cycle an odd number of quarter wavelengths long with electron work period, the openings in said grid said electron emitting section axially straddling being proportioned to provide an inductive re a voltage loop position one-half wavelength from actance in the cathode circuit smal1 in relation to the capacitative reactance between anode and 40 one radio-frequency end of said resonator ele ments. cathode thereby causing said tube to oscillate by 26. In a self-resonating oscillator tube having the feedback due to anode-cathode capacity only. inner, outer and intermediate space insulated 18‘. .An oscillation generation circuit comprising a triode tube having an anode shielded from a conductors having adjacent physically closed cathode by a single grid except for intermediate grid openings in the same grid, a resonant cir cuit having one end connected to said cathode, a ends and opposite physically open ends and means for passing electrons from said inner to said outer conductors, means for closing said physically open ends comprising a quarter wave hollow resonator section mounted on each of two of said conduc resonant circuit connected at one end to said an ode, the other ends of said circuit being connected together, a substantially reactance-free connec tors and extending toward the facing conductors, tion from said grid to said connected ends, means for impressing a direct-current potential between said cathode and anode with said anode grounded, said potential being such as to provide a half said resonator section extending between a volt age loop and a current node during operation of said tube. cycle electron work period, the openings in said - transmission line having inner and outer con ductors spaced by direct current insulation, com grid being proportioned to provide an inductive reactance in the circuit cathode small in relation to the capacitative reactance between anode and cathode thereby causing said tube to oscillate by the feedback due to anode-cathode capacity only with a half-cycle electron work period. 19. An oscillation generation circuit comprising a triode tube having an anode shielded from a cathode by a single grid except for intermediate grid openings in the same grid, a resonant circuit having one end connected to said cathode, a reso nant circuit connected at one end to said anode, the other ends of said circuit being connected to gether, a substantially reactance-free connection ‘ 27. Means for terminating a radio-frequency prising a quarterwave anti-resonant choke posi tioned on one of the conductors of said line fol lowed by a second quarterwave anti-resonant choke spaced, by a quarterwave line section from said ?rst choke. 28. Apparatus in accordance with claim 27 wherein said chokes are toroidal chambers bridg ing a physical cut in one of said conductors. 29. Apparatus in accordance with claim 27 wherein said chokes are cylinders positioned on one of said conductors by end ?anges, the other end of said cylinders being open, with said cylin ders close to and concentric with the other con from said grid to said connected ends, means for 70 ductor. ‘ impressing a direct-current potential between 30. In combination with a main ‘concentric said cathode and anode with said anode grounded, transmission line carrying high frequency power, said potential being such as to provide a half-cycle a high loss transmission line connected to said electron work period, the openings in said grid main transmission line at a current loop,'said being proportioned to provide an inductive react branch transmission line being of an odd number 21 2,411,299 of quarter wavelengths long with respect to the wavelength of the standing waves in said line to absorb power therefrom, and means for measur ing the heat liberated in said branch transmis sion line. 31. In combination with a main concentric transmission line carrying high frequency power, a high loss transmission line connected to said main transmission line at a current loop, said branch transmission line being dimensioned to absorb a predetermined percentage of the power carried by said line, and means for measuring the heat liberated in said branch transmission line. main transmission line at a current loop, said branch transmission line being dimensioned to absorb a predetermined percentage of the power carried by said line, the central element of said branch transmission line being a hollow insulat ing element, means .ior ?owing a conductive ?uid through said central element at will, and means for measuring the heat 01’ the ?uid passing through said central element. 10 34. Apparatus in accordance with claim 33 wherein said branch transmission line is an odd number of quarter wavelengths long to absorb all the power in said main transmission line. 35. Apparatus‘ in accordance with claim - 33 ' 32. In combination with a main concentric transmission line carrying high frequency power, a branch transmission line connected to said main transmission line at a current loop, said branch transmission line being dimensioned to absorb a is wherein said branch transmission line is an odd number of quarter wavelengths long to absorb all the power in said main transmission line, and wherein said ?uid is a conductive brine. 36. An electron discharge device comprising predetermined percentage of the power carried 29 three substantially parallel disposed walls form by said line, the central element of said branch ing a pair of resonators having a common wall, transmission line being normally non-conductive, said common wall having an opening therein, and means for making said central element conduc~ an electron emitting surface positioned in one of tive at will, and means for measuring the heat said resonators opposite said opening, said open ing and said emitting surface being positioned to liberated in said branch transmission line while conductive. straddle a voltage loop between the ends of said 33. In combination with a main concentric transmission line carrying high frequency power, a branch transmission line connected to said resonators. DAVID H. SLOAN.