US2493046A

US2493046A - High-frequency electroexpansive tuning apparatus

Info

Publication number: US2493046A
Application number: US544730A
Authority: US
Inventors: Sigurd F Varian; Edward L Ginzton
Original assignee: Sperry Corp
Current assignee: Sperry Corp
Priority date: 1942-08-03
Filing date: 1944-07-13
Publication date: 1950-01-03
Anticipated expiration: 1967-01-03
Also published as: FR953070A

Description

Jan. 3, 1950 s.'F. VARIAN ET AL HIGH-FREQUENCY ELECTROEXPANSIVE TUNING APPARATUS Original Filed Aug. 3, 1942 INVENTORS AS. F. l/qR/Am BY 5.4 G/NZTO/V m m? W ATTOR/VZY Patented Jan. 3, 1950 HIGH-FREQUENCY ELECTROEXPANSIVE TUNING APPARATUS Sigurd F. Varian and Edward L. Ginzton, Garden City, N. Y., assignors to The Sperry Corporation, a corporation of Delaware Original application August 3, 1942, Serial No. 453,482. Divided and this application July 13, 1944, Serial No. 544,730

20 Claims.

The present case is a, true division of our copending application Serial No. 453,482, filed August 3, 1942, for High frequency tube structure, and now U. S. Patent No. 2,475,652, granted July 12, 1949.

This invention relates, generally, to ultra high frequency electron beam velocity grouping tubes, and, more specifically, to improvements in oscillator or amplifier types of high frequency tubes of the general type disclosed in copending application Serial No. 420,771, entitled High frequency tube structures, filed November 28, 1941, in the names of William W. Hansen and John R. Woodyard, and now U. S. Patent No. 2,450,893, granted October 12, 1948. in which velocity grouping tubes utilizing buncher and catcher resonators as well as a third resonator serving as a buffer stage are described.

The purpose of the addition of this buffer resonator was to provide a more or less electromagnetically independent resonator from which large and variable amounts of high frequency energy might be extracted without adversely reflecting back into the prior resonators and thereby altering the output frequency of the tube. In this type of tube this result has been to a large extent accomplished since the only electromagnetic coupling between the buffer resonator and the earlier resonators is along the interconnecting electron stream itself.

In this prior art disclosure, no means for gang tuning of the three resonators was provided, a mechanical fine tuning device being generally utilized to control the buncher or first resonator only, since this resonator is the chief frequency determining element of the tube. This resonator and the catcher or second resonator as well as the bufier or third resonator generally have coarse tuning means. Since the catcher and buffer resonators can be made to have broad resonance curves, such coarse tuning is usually suflicient, though the frequency range of the tube is naturally limited by the lack of fine tuning of the latter resonators.

One object of the present invention is to provide a simple gang tuning device for simultaneously changing the resonant frequency of as many resonators of the high frequency type as may be desired.

A further object is to provide a gang tuning device in which equal parallel relative motions of the respective resonator grids or frequency control elements of a multi-resonator tube may be produced.

A still further object is the provision of a gang tuning parallel motion device electrically controllable by a current which may be related to the desired output frequency, and incorporating mechanical means for independent coarse adjustment of individual resonators.

Other objects and advantages will become apparent from the specification, taken in connection with the accompanying drawing wherein the invention is embodied in concrete form.

In the drawing, the single figure is a fragmentary partial cross-section elevation View of a preferred form of the present invention.

Referring now to the figure, there is shown an electron beam velocity grouping vacuum tube consisting of an indirectly heated oxide coated cathode I placed axially in an end bell jar 2 in front of a smoothing or accelerating grid 1, grid 1 forming an entrance into axially spaced resonators 3, 4 and 5. Resonators 3 and 4 are formed by a conducting tubular outer wall l2, flexible end diaphragms l0 and II, and flared inner conducting tubes 8 and 9, which cooperate to form electron beam drift space 6, and whose outwardly flared portions form a separating wall between resonators 3 and 4. Holes 23 are placed in the flared drift tubes 8 and 9 in order to accommodate coupling loop :24, opposite ends of which ex-. tend into resonators 3 and 4. Grids l6, l6 and I8, I 8 are shown in resonators 3 and 4, respectively, through which the electron beam from emitter I is projectedby a unidirectional acceleration voltage placed between cathode l and grid 1. A tube l 9 projects from resonator 4, on whichv tube is mounted a rigid end plate I'5 which, to-

gether with tubular outer wall I3, flexible end spaced circular cooling flanges H. An end cooling flange l'! is made of greater thickness than fianges IT in order to prevent damage thereto due to handling. Similar cooling flanges BI and 5! are provided between resonators 4 and 5, and between resonator 3 and end bell jar 2, respectively.

Resonators 3, 4 and 5 are provided with similar

concentric line structures

25, 26 and 21 for the removal or introduction of energy from or into any one or anycombination of these-respective resonators. These concentric line devices consist of an inner conducting rod 29 terminated inside of the resonator by a coupling loop 28, which joins directly to the inner wall of a tubular outer conductor 30,. whose inner surface is preferably plated with a highly conducting material such as copper or silver. In construction, inner conductor 29, whose outer surface is also preferably plated with a highly conducting material is sealed by glass to metal end seal 33 concentrically in a short flanged tubular outer conductor 3|. The tube 30 is silver-soldered in position in the resonator wall I2 or l3, and the

structure

29, 31, 33 is inserted into tube 30 and spot-welded at 32. The end of loop 28 and the inner wall of tube 33 adjacent thereto have been previously tinned with a soft solder, so that the application of a slight amount of heat to the exterior of tube 30 near its point of contact with loop 28 completes the electrical junction. Thus, a method of assembly of the concentric line structure is provided without exposing the glass to metal end seal 33 to the elevated temperatures necessary for silver-soldering tube 30 in place, thereby eliminating the danger of cracking seal 33 during attachment to a resonator. This method also eliminates oxidation of the inner surface of tubular conductors 30 and 3,! and the outer surface of conductor 29, thereby preventing the increased impedance which would naturally result from such oxidation.

Flanges

48, 49, 50 and are provided on end bell jar 2, outer conducting wall I2 of resonators 3 and 4, outer conducting wall 13 of resonator 5, and finned end tube 20, respectively, in order to transmit relative motion from the tuning device of this invention to the respective grids. Spaced directly oppositely on each of these four flanges at an angular separation of substantially 120 are three holes through which are inserted three rigidly clamped exteriorly threaded thin tubes or thermal struts 52, each of which extends parallel to the vacuum tube axis and projects. slightly past flanges 48 and 5| at opposite ends. Each of; the three thin tubes 52 is rigidly held at each flange in a thermally insulating clamp, each clamp consisting of an insulating bushing, 53, insulating washer 54, and on opposite. Sides of the flanges, two metal washers 55 and two metal nuts 55. The ends of the thin tubes 52 are closed by apertured insulating plugs 51, 51', through which heater wires 58 extend. Heater wires 58 run the length of the tube 52 and may be supported therein by a powdered insulat g material such as magnesium oxide, or may be supported only by the end plugs 51, 5 1. The ends, of heater wires 58. in each of the three thin tubes 52 are, connected in series by the leads shown and supplied with current controlled by a rheostat. ill from battery 5.9. If desired, the inner and outer surfaces of tubes 52 may be treated in any well-known manner, as by coating the same with a reflecting material, to increase or decrease thermal radiation from their surfaces.

In operation, the electron beam from cathode I is. accelerated successively through grid 7, grids I6, [6' of resonator 3, grids l1, ll of resonator 4, grids 2t, 22, of resonator 5, and finally impinges upon the inner wall of end tube, 25. Coupling loop. 24 m y be adjusted so. that the electrons arrive between grids l8 and I8 of resonator 4 in a, somewhat under-bunched condition, and do not obtain optimum bunching until they arrive between grids 2| and 22 of resonator 5. Such an adjustment produces the result that resonator 4 is excited only so much as, is necessary to properly excite resonator 3, while buffer resonator 5, from which it is usually intended to. extract high frequency energy, is excited to the. highest amplitude o: oscillation, possible.

s is w ll nown. lectron beam velocity modulating tubes are generally provided with flexible diaphragms, such as diaphragms II, I 0, I4 of resonators 3, 4, 5, respectively, in order to enable the changin of the distance b tween the respective resonator grids and thus enable individual or gang tuning of the resonance frequency of the resonators. Such tubes are also usually provided with flanges, such as flange 48 on end bell jar 2, flange 49 on resonators 3 and 4, flange 50 on resonator 5, and flange 5| on finned end tube 20, which normally cooperate with mechanical devices for obtaining the desired relative grid motions. In the case of tworesonator tubes, gang tuning devices of mechanical types such, as those disclosed in prior application Serial No. 342,912, entitled High frequency tube structures and filed June 28, 1940, in the names of William T. Cooke, Joe J. Caldwell, Jr., and David G. Clifford, have proved useful, but in the case of multi-resonator tubes, mechanical tuning becomes a complex problem for the following reasons. Referring to the drawing, if flange 5D. is relatively fixed and used to support the tube, as from an apparatus panel, it is seen that for gang tuning, if flange 5! is moved one unit to the left, flange 49 must then be moved one unit to the right, and flange 48 must be moved two units to the right. A mechanical motion device to perform this function must necessarily be complex. Also, in gang tuning of multi-resonator tubes, which necessarily utilize long electron beams, there is the further requirement that the flanges must all be moved absolutely parallel to each other in order to preserve the alignment of the tube.

In the figure, it is seen that heat generated by current passing through heater wires 58 will cause uniform thermal expansion of the thin tubes. 52;, which in turn will produce equal parallel relative motion of the

flanges

48, 48, 5B and 5!.. This motion of the flanges is transmitted to the grids, changing the relative spacing thereof; resulting in simultaneous tuning of all resonators. A further advantage of this novel system of gang tuning is that it may readily be adapted to a system of remote automatic frequency control by replacing battery 59 and rheostat 60 by any suitab e voltage source which provides a current related to the desired output frequency. Initial individual tuning of the resonators 3, 4 and 5. is accomplished by mechanical adjustment of the. nuts 56. This thermal type of tuning device may be equally well applied to single-resonator, or to two-resonator tubes, or to tubes having a plurality of resonators, wherever tuning by parallel motion of the resonator grids is necessary, or wherever electrically controllable remote tuning is desired.

Since many changes could be made in the above construction and many apparentl widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

A high frequency tube structure comprising electronic means for producing an electron stream, a plurality of hollow resonators consecuti-vely disposed along the path of said stream, said resonators having flexible wall portions to enable relative motion of opposite wall areas during the tuning of said resenators, and means for efi'ecting gang tuning of said resonators comprise ing a single thermal strut coupled at different points along its length to each of said'flexible wall portions of all said resonators, and heating means in said structure for heating said thermal strut along its entire length to effect expansion and contraction thereof resulting in the deflecting of the flexible wall portions of said resonators and the gang tuning of the latter.

,2. Apparatus as defined in claim 1, wherein at least one of said resonators has an additional wall portion which remains fixed relative to said flexible wall portion of said one of said resonators, said high frequency tube structure further including an additional thermal strut coupled to said additional wall portion and said flexible wall portion of said one of said resonators.

1 v3. A high frequency tube structure comprising electronic means for producing an electron stream, a plurality of hollow resonators consecutively mounted along the path of said stream, said resonators having reentrant portions and flexible wall areas enabling relative movement between said reentrant portions and the oppo-- site walls of the resonators for efiecting tuning thereof, said reentrant portions and the said opposite walls of the resonators being apertured in said stream path, a plurality of thermally expansible and contractible elements disposed around and each connected to said reentrant portions and said opposite walls of all said resonators, and remotely controlled means in said structure for simultaneously heating said elements, whereby simultaneous relative movementbetween said reentrant portions and the opposite walls of said resonators is effected while maintaining said reentrant portions and walls substantially parallel, thereby eirecting gang tuning of said resonators.

4. High frequency tube structure comprising a substantially cylindrical member, deformable walls at opposite ends of said member, aligned electrodes in said deformable walls, wall means within said member rigid with said member and substantially separating the space within said member into two resonator chambers, aligned electrodes in said wall means, each electrode on said wall means being located adjacent an electrode in one of said deformable walls, a single longitudinally expansible and contractible thermal tuning strut connected at opposite ends to the electrodes in said deformable walls and connected intermediate its ends with said electrodes on said wall means, and means coupled to said strut for electrically energizing said tuning strut, said strut being operable under varying degrees of energization to simultaneously and similarly control the spacings between said adjacent electrodes for gang tuning said resonators.

5. High frequency tube structure comprising electronic means for producing an electron stream along an axis, a plurality of hollow resonators aligned parallel to said axis along the path of said stream, said resonator means having a plurality of pairs of relatively displaceable electrodes in said resonators, one pair being included in each resonator, and a single thermal tuning element substantially parallel to said axis operatively connected to all of said electrodes for simultaneously controlling the spacing between each pair of electrodes for gang tuning said resonator means.

6. The high frequency tube structure defined in claim 5, wherein said electrodes of each pair; are substantially parallel, and a. further thermal tuning element operatively connected to said pair ofelectrodes at at least two points along said further tuning element for controlling the spacing between the electrodes to effect substantially parallel relative movement of said electrodes.

7. High frequency tube structure comprising electronic means for producing an electron stream, hollow resonator means alongthe path of said stream, said resonator means having a plurality of pairs of relatively displaceable electrodes inadjacent walls of said resonator means, means rigidly interconnecting one electrode of one of said pairs with one electrode of another of said pairs, and a single thermal tuning element operatively connected to all of said elec-- trodes for simultaneously controlling the spacing between the electrodes of each of said pairs for gang tuning said resonator means, said ther mal tuning element comprising an electrically.

energizable element connected at one end to the other electrode of one of said pairs and at the opposite end to the other electrode of another oi.-

said pairs, and connected intermediate its ends to said rigid interconnecting means.

8. A high frequency electronic tube comprising a hollow structure, deformable walls at opposite ends of said structure, aligned electrodes shiftably mounted in said walls, wall means within said member for separating the space within said structure into two adjacent resonator chambers,

aligned electrodes on said wall means, said elec-' trodes on said wall means being fixedly spaced and each being located closely adjacent another electrode on one of said deformable walls, and

an expansible and contractible thermal tuning. member mounted on said hollow structure with its opposite ends connected to said shiftably mounted electrodes, and connected intermediate its ends to the electrodes on said wall means, said tuning member being electrically energizable to similarly control the spacing between the electrodes of each said pair.

9. High frequency apparatus comprising means for producing an electron stream, hollow resonafor means algined along an axis and adapted to contain oscillating electromagnetic fields and arranged along the path of said stream for interaction therewith, individual members on said resonator means shiftable for tuning each of said fields, and a single thermally controlled element substantially parallel to said axis connected to all said members for simultaneously and similarly varying the resonant frequency of said fields.

19. A high frequency tube structure comprising electrode means for producing an electron stream, three hollow resonators consecutively disposed, along the path of said stream, four individual tuning adjusting means coupled to said resonators, and a single thermally energizable tuning element connected to all said individual means, said tuning element being connected to each of said individual means at a different point along its length for simultaneously adjusting the frequency of said resonators.

11. Ultra high frequency tube structure comprising electronic means for producing an electors, said elements being oppositely movable for, effecting similar changes of frequency therein,

15' anda single linear thermally expansible member.

amen

attached. at an intermediate point to said base and at opposite endsto said tuning elements for simultaneously and: similarlyvarying the. rear-- nant frequencies. of said resonators.

12. Ultra high frequency apparatus comprising means defining apair of aligned resonator chamhers, means at each resonator for individually tuning: each of said resonators, a single thermally expansible and contractible' element connected to all. said individual tuning means for simultaneously tuning said resonators, and: means in said apparatus for controlling thermal energization of said expansible and contractible element, sai'd single element being connected, to said tuning means at at least three points along said single element;

. 13'. Ultra high frequency apparatus-comprising electronic means for producing an electron stream, means defining a pair of resonator chamhers disposed along the path of said stream, shiftable electrode means in. each of said resona-- tors; individual tuning adjustment means connected to each shiftable electrode means, and a single thermallyenergized tuning. element connected to all said individual means at at least three. points along said; tuning element for simultaneously adjusting the frequency of saidresonator chambers.

:14. The ultra high frequency apparatus defined in claim 13; wherein said resonator chambers'are provided. with deformable walls, and said shiftable electrodes are carried by said walls.

15. High frequency apparatus comprising a plurality of consecutively aligned cavity resonatorseach having a pair of relativelymovable ele- IHBHtS; for efi'ectingl tuning thereof, means con-- necting one element of each resonator to an element of a succeeding resonator, athermally expansible. strut rigidly connected at different points along its length to one element of each resonator, and heater means adjacent said strut.

for applying heat thereto to produce thermal ex-- pansion of said strut and consequent gang tuning of said resonators.

16. High frequency apparatus comprising a pair of consecutively aligned cavity resonators each having a pair of relatively movable elements. for effecting tuning thereof, means connecting, one element of one of said resonators to an element of the other of. said resonators; a thermally ex-pansible strut rigidly connected at one point to the other element of the first of said resonators, at a second point spaced therefrom to the other element of the other of said resonators, and at an intermediate point to. said interconnected cments; and heater means adjacent said strut for. applying heat thereto to produce thermal ex,- pansion of said strut and consequent gang tuning of said resonators.

17. High frequency apparatus comprising a pair of consecutively aligned cavity resonators each having a pair of relatively movable elements for efiecting tuning thereof, means rigidly connecting one element of one of said resonators to an element of the other of said resonators, and an electrically controllable thermally expansiblestrut rigidly connected at one point to the other element of said one resonator, at a separated point to the other elementof said other resonator, and at an intermediate point to said connected elements, whereby, upon energization of said strut, expansion thereof is produced for gang tuning said resonators.

:18; High frequency apparatus. comprisinga.

pair ot cavity resonators each having; a pair of 8 parallefelementse relatively movable along a com-' mon axis. for effecting tuning of said resonators, means rigidly connecting one element 01 one of said resonators to an: element of the other of said; resonators, and a plurality of similar electrically energizable thermally expansible struts symmetrically disposed about said: axis and each rigidly connected at one point to the other element of said one resonator, at a separated point to: the other element of said resonator, and at an intermediate point to said connected elements; said plurality of struts being simultaneously controllabl'e' in equal extents whereby, upon. electrical energization of said struts producing expansion thereof, said pairs of elements are relatively moved to produce gang tuning of said resonators with said pairs of elements being retained mutually parallel.

19. High frequency apparatus comprising three consecutively aligned cavity resonatorseach having a pair of relatively movable elements for effecting tuning thereof, means connecting oneelement of a first resonator to an element of a; second? resonator, means connecting the other element of said second resonator to an elementof said: third resonator, and an electrically ener gizable expansible strut rigidly connected at one point to the other element of said first resonator, at a separated point to the other element ofsaitl third resonator, and at a pair of separated points intermediate said first-named points, respectively to first andsecond connecting means, whereby; upon electrical energization of said strut producing expansion thereof, gang tuning of said three resonators is effected.

20; High frequency apparatus comprising aplurality of tuned circuits each having apair of relatively movable elements for effecting tuning thereof, said pairs of relatively movable elements being connected to aligned electron-permeable regions, means connecting one element of. one of said circuits to. an element of a succeeding circuit, and electrically energizable expansibl'e strut means rigidly connected at one point to the other element of said first resonator, at a separated point to the element of said succeeding circuit, and at an intermediate point to said connected. elements, whereby, upon electrical energization of said strut to produce expansion. thereof, gang tuningv of said circuits is efiected.

SIGURD F. VARIAN. EDWARD L. GINZTON.

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

UNITED STATES PATENTS Number Name Date" 1,559,714 Lilienfeld Nov. 3, 1925' 1,658,953 Theremin Feb. 14, 1928- 2,162,343 Brace June 13, 19-39 2,216,170 George Oct. 1, 1940- '2,222,902 Hahn Nov. 26, 1940 2,311,658 Hansen et a1 Feb. 23, 1943 2,345,642 Varian et al Apr. 4, 1944 2,408,817 Snow Oct. 8, 1946 2,414,785 Harrison et al Jan. 21, 1947' FOREIGN PATENTS Number Country Date 53.7.,518- Great Britain June 25, I941