US2894227A - R-f coupling arrangements for traveling wave tubes - Google Patents

Description

y 1959 J. H. BRYANT HAL 2,894,227

R-F COUPLING ARRANGEMENTS FOR TRAVELING WAVE TUBES Filed Aug. 21, 1952 2 She ets-Sheet 1 VIII An/f ENW July 7, 1959 J. H. BRYANT ETAL 2,894,227

R-F COUPLING ARRANGEMENTS FOR TRAVELING WAVE TUBES Filed Aug. 21, 1952 2 Sheets-Sheet 2 129. 5 T4 mm I IIIIIIIII/l/I/ lIllIl/llIlIIlllIII/lll.

.g/ pw J INVENTORS 1 41 JOHN H- BRYANT ALBERT "1- PE/FER 50 BY 7297 w. W/LMAKTl-l ATTORNEY R-F' COUPLING ARRANGEMENTS FOR TRAVELING wAvE TUBES JolmH. Bryant and Albert G. Peifer, Nutley, and Robert W. Wilmarth, Rutherford, N.J., assignors to international Telephone and Telegraph Corporation, a corporation of Maryland Application August 21, 1952, Serial No. 305,538

14 Claims. (Cl. 33397) This invention relates to traveling wave electron discharge devices and more particularly to R-F coupling arrangements therefor.

The traveling wave type of tube is particularly useful in wide band microwave systems since it is capable of amplifying radio frequency energy over a very wide band of frequencies. The tube includes a form of transmission line, usually a helix, for transmission of microwave energy for interaction with an electron beam closely associated with the line. The helical characteristic of the transmission line is such that the axial velocity of microwave signals conducted along the helical path is approximately the same as or slightly slower than the velocity of the electrons of the beam, whereby the electric field of the microwave signals interacts with the electron beam for amplification of the microwave signals. In the copending application of J. H. Bryant and T. J.

Marchese, Serial No. 221,862, filed April 19, 1951, a compact traveling wave tube is provided characterized in that two coaxial terminals for the radio frequency input and output connections are brought out at one end.

It is one of the objects of the present invention to provide an R-F coupling arrangement for a traveling wave tube having its R-F connections at one end, suitable for connection to either coaxial lines or waveguides.

It is a further object of this invention to provide a traveling wave tube which is interchangeably adapted for use with either coaxial line or waveguide transmission systems.

A feature of this invention is the rigid R-F end structural arrangement of a traveling wave tube having the output and input R-F connections located at the same end. The end plate of such a traveling wave tube is made in two parts, an inner disc through which R-F output and input coaxial terminals are disposed and an annular ring portion receivably mounted on the envelope of the tube. An adapter is provided to couple said coaxial terminals to input and output line probes coupled to a section of Waveguide. A second adapter is provided which may be utilized in place of the first adapter for coupling said R-F terminals to coaxial lines through usual R-F circuit fittings. Through the use of either one of the two adapters with a single traveling wave tube, the tube may be adapted for insertion in either a coaxial line or waveguide transmission system.

The above-mentioned and other features and objects of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which:

Fig. l is an 'explodedsectional view of the R-F end of a traveling wave tube and adapter for connection to 'a'coa'xial line transmission system;

Fig. 2 is a cross-sectional view taken along lines 2-2 of Fig. l;

Fig. 3 is an exploded sectional view of the R-F end of a traveling wave tube and adapter for connection to a waveguide transmission system; and

atent 2,894,227 Patented July 7, 1959 ice Fig. 4 is a cross-sectional view taken along lines 44 of Fig. 3.

Referring to Figs. 1 and 2 of the drawing, the traveling wave tube and adapter for coupling to an R-F coaxial line transmission system is shown to comprise a traveling wave tube 1 having a cylindrical housing 2 containing in one end thereof a radio frequency transmission line coupling unit 3, and in the opposite end thereof an electron gun unit (not shown). The housing has mounted thereon a magnetic unit 4, shown to be an electromagnetic coil, although a permanent magnet may be used. The R-F transmisison line coupling unit 3 comprises a barrier plate 5 through which are mounted input R-F line connection 6 to the helix 7, output R-F line connection 8 to helix 7, and an electron collector terminal 9. The input connection 6 comprises a coaxial line having an outer conductor 10 and an inner conductor 11, the connections being closed by insulator 12 sealed between the outer and inner conductors 10 and 11. The output connection 8 likewise comprises a coaxial structure having an outer conductor 13 and an inner conductor 14 sealed by insulation 15. The inner conductors 11 and 14 of the R-F line connections 6 and 8 extend beyond the outer conductors 1'0 and 13 forming R-F input probe 16 and R-F output probe 17. Mounted on the inner side of barrier plate 5 is a radio frequency transmission line preferably in the form of a helix 7, although some other configuration, such as a plurality of annular discs or plates, may be used, whereby the axial velocity of the radio frequency energy is made preferably slightly slower than the velocity of the beam of electrons projected from the electron gun unit.

End plate or cup 18 is mounted to the housing 2 by means of its annular rim 19. The input and output R-F line connections 6 and 8 are brought through holes 20 and 21 in the end plate 18. Hollow posts 22 and 23 protect the connections 6 and 8 and support the connections in alignment to be coupled to the adapter. Rigidly secured to end plate 18 are supporting posts 36 and 37 each having a threaded hole in its outer end to receive a connecting screw.

The adapter for coupling an R-F coaxial transmission system to the R-F line connections 6 and 8 of traveling wave tube 1 comprises a base plate 24 to which is mounted, by means of screws 25 and 26, standard coaxial coupling units 27 and 28. Each of the coaxial coupling units 27 and 28 comprises an outer conductor 29 separated from an inner conductor sleeve 30 by insulation 31. R-F coaxial cable is connected to the standard coupling units 27 and 28 in the usual manner such as by screw threads or studs. The inner conductors 3%) of coupling units 27 and 28 telescope with the probes 16 and 17 of R-F line connections 6 and 8. The coaxial couplers 27 and 28 abut upon and are rigidly secured to the base plate 24. In electrical contact with the outer conductors 29 of coaxial couplers 27 and 28 and supported by base plate 24 are hollow sleeves 33 and 34 whose inside diameter is equal to the outside diameter of the R-F line connections '6 and 8.

In order to couple the traveling wave tube 1 into a coaxial line transmission system, the sleeves 33 and 34 are fitted over the R-F line connections 6 and 8 of the traveling wave tube and screws 35 are inserted through the base plate 24 into the threaded holes of posts 36 and 37 which are rigidly attached to end plate 18. When properly aligned, the outer conductor of the input R-F coaxial transmission line is coupled through coupling unit 28 and sleeve 34 to the outer conductor 10 of the R-F line connection 6 while the inner conductor probe 16 is telescoped into coupling unit 28. The input energy is then coupled to the helix 7 through a usual R-F transmission line. The outer conductor of the output R-F coaxial transmission line is coupled through coupling unit 27 and sleeve 33 to the outer conductor 13 of the output R-F line connection 8 and the inner conductor is coupled through the telescoping of probe 17 and inner conductor 14. The use of sleeves 33 and 34 and the posts 36 and 37 provide a rigid support for the coupling adapter.

Referring to Figs. 3 and 4, an embodiment of an adapter for coupling a traveling wave tube to a waveguide transmission system is shown wherein parts identical with those shown in Figs. 1 and 2 are designated by the same reference characters. The traveling wave tube 1 has barrier plate through which input and output R-F line connections 6 and 8 are disposed. Rigidly coupled to barrier plate 5 by means of nut and bolt 39 is the end plate or cup 18 which is held in place by means of its annular rim 19. R-F line connections 6 and 8 extend through end plate 18 secured thereto by means of nut and bolt 39. The electron collector terminal is not shown in the view of Fig. 2 in order to show nut and bolt 39 coupling the end plate 18 and posts 36 and 37 to barrier plate 5 which is not shown in the view of Fig. 1. The coupling adapter for a waveguide transmission system comprises a section of rectangular waveguide 43 divided into an input and output section by means of partition 44. Rigidly secured to the outer surface of waveguide 43 are four sleeves 45, 46, 47, and 48. Sleeves 45 and 46 fit over R-F line connections 6 and 3 in such a manner that probes 16 and 17 extend into waveguide section 43 a quarter or an odd multiple of a quarter wavelength from partition 44. Sleeves 4-7 and 48 are so located that they are received over posts 36 and 37. Sleeves 47 and 48 have a plurality of set screws 49 therethrough which when tightened cause the waveguide 43 to be rigidly supported by the posts 36 and 37. In use, the adapter has its sleeves 45 and 4-6 slipped over and making contact with the outer conductors of the input and output R-F connections 6 and 8 of the traveling wave tube 1. When these are in position, the input and output probes 15 and 17 are so located that they will couple energy away from and into the waveguide section 43. When so located, sleeves 47 and 48 will be in place over supporting posts 36 and 37 at which time set screws 49 may be tightened providing a rigid coupling between the input and output R-F line connections 6 and 8 of the traveling wave tube It and the R-F wave-guide termination. Flanges 50 and 51 on the waveguide section 43 are provided in order to facilitate incorporating waveguide section 43 into a waveguide transmission system. Braces 52 are provided for additional mechanical support between the flanges 5t and 51 and the rectangular waveguide section.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope or our invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. In an electron discharge device having a housing with a pair of coaxial radio frequency terminals extending inv parallel relation through a wall thereof, each of said terminals including a vacuum seal between their inner and outer conductors; a coupling adapter for said terminals comprising a plate carrying radio frequency transmission line couplers on one side and a pair of sleeves on the other side thereof, each sleeve being in communication with one of said couplers and means spaced from. said sleeves and said couplers to removably secure said plate to said housing wall in a fixed rigid position with said sleeve and said terminals in slidable telescoped relation to thereby protect said vacuum seals and said terminals.

2. In an electron discharge device according to claim 1, wherein said housing wall has at least one rigid supporting post disposed adjacent said terminals and said plate is provided with means for securing the plate to said post.

3. In an electron discharge device according to claim 2, wherein said post has a threaded opening therein and said means for securing said plate to said post includes an element threadably receivable in said opening.

4. In an electron discharge device according to claim 2, wherein the means for securing said plate to said post includes a sleeve adapted to telescope over said post and a set screw carried by said sleeve for engagement with said post.

5. In an electron discharge device according to claim 1, wherein the transmission line couplers comprise a flanged sleeve forming an outer conductor, and a body of dielectric material supported therein having a conductive sleeve axially thereof to form an inner conductor, said inner sleeve being adapted to telescope with the inner conductor of one of said terminals when said adapter is applied to said device.

6. In an electron discharge device according to claim 1, wherein each of said couplers comprises a rectangular waveguide with an opening in alignment with an associated one of said sleeves, the inner conductor of each terminal being adapted to extend as a probe into the corresponding waveguide.

7. In an electron discharge device according to claim 1, wherein said plate comprises a wall of a waveguide section, said waveguide section having a partition dividing it into two couplers for communication with corresponding ones of said sleeves.

8. In an electron discharge device according to claim 7, wherein said member has at least one post adjacent said terminals and the wall of said waveguide section has a third sleeve adapted to be received over said post and means for securing said third sleeve to said post.

9. A coupling adapter for a device having a pair of adjacent parallel disposed coaxial terminals, each of said terminals including a vacuum seal between their inner and outer conductors, comprising a plate carrying radio frequency transmission line couplers on one side and a pair of sleeves on the other side thereof, each said sleeve being in communication with one of said couplers, said sleeves being adapted to slidably telescope with said terminals and means spaced from said sleeves and said couplers for removably securing said plate in a fixed rigid position on said device to thereby protect said vacuum seals and said terminals.

10. A coupling adapter according to claim 9, wherein the transmission line couplers comprise a flanged sleeve forming an outer conductor, and a body of dielectric material supported therein having a conductive sleeve axially thereof to form an inner conductor, said inner sleeve being adapted to telescope with the inner conductor of the terminal telescoped with the corresponding sleeve of said adapter.

11. A coupling adapter according to claim 9, wherein each of said couplers comprises a rectangular waveguide with an opening in alignment with an associated one of said sleeves, the inner conductor of each terminal being adapted to extend as a probe into the corresponding waveguide.

12. A coupling adapter according to claim 9, wherein said plate comprises a wall of a waveguide section, said waveguide section having a partition dividing it into two couplers for communication with corresponding ones of said sleeves.

13. A coupling adapter according to claim 12, wherein said device has at least one rigid supporting post disposed adjacent said terminals and said wall of said waveguide section has a third sleeve adapted to be telescoped with said post and means for securing said third sleeve to said post.

14. An energy coupling adapter for an electron discharge device gornprising a housing for said electron.

discharge device having an end wall, a pair of adjacent parallel disposed coaxial terminals extending through said end wall, each of said terminals including a vacuum seal between their inner and outer conductors, a plate carrying radio frequency transmission line couplers on one side and a pair of sleeves on the other side thereof, each of said sleeves being in communication with one of said couplers, said sleeves being adapted to slidably telescope with said terminals, and means spaced from said sleeves and said couplers for removably securing said plate in a fixed rigid position on said end Wall to thereby protect said vacuum seals and said terminals.

References Cited in the file of this patent UNITED STATES PATENTS 1,986,269 Jermain Ian. 1, 1935 Potter July 5, 1938 Montgomery Aug. 30, 1949 Barnett Aug. 1, 1950 Melcher May 15, 1951 Woodyard July 15, 1952 Hines Aug. 26, 1952 Hansell Oct. 21, 1952 Nichols Jan. 6, 1953 Gilbert Nov. 17, 1953 Sinclair et al. Feb. 28, 1956

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