US2833962A

US2833962A - Traveling wave electron discharge devices

Info

Publication number: US2833962A
Application number: US401582A
Authority: US
Inventors: Arditi Maurice
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; International Telephone and Telegraph Corp
Priority date: 1952-04-08
Filing date: 1953-12-31
Publication date: 1958-05-06
Anticipated expiration: 1975-05-06

Description

May 6, 1958 M. ARDIT! 2,833,962

TRAVELING WAVE ELECTRON DISCHARGE DEVICES Filed Dec; 31, 1953 2/ 22 ,9 as n 9 24 5\ l 3 2 ,25 k I 7 i /5 26 P27 I, I 2-1 2 9 l0 INVENTOR MAt/R/C' ARD/T/ ATTORNEY United States Patent TRAVELING WAVE ELECTRON DISCHARGE DEVICES Maurice Arditi, Clifton, N. J., assignor to International Telephoneand Telegraph Corporation, Nutley, N. J., a corporation of Maryland Application December 31, 1953, Serial No. 401,582 12 Claims. (Cl. 315-39) This invention relates to traveling wave electron discharge. devices and more particularly to coupling. arrangements for coupling such devices to radio frequency and other electrical leads. This application is a continuation-in-part of my copending application, Serial No. 314,381, filed Oct, 11, 1952, now abandoned.

In traveling wave tubes and like devices, particularly where an electrode in the form of a high impedance line such as a helical line is employed, it is often ditficult to properly match the radio frequency input and output terminal connections of the tube to the helical line,

especially where wide band operation is required. Where rectangular waveguides are employed these input and output connections are rather critical requiring tuning shorts to effect an impedance match. Such tuning shorts, however, are frequency sensitive and restrict the band width. Where coaxial lines are used for radio frequency input and output connections to obtain wider band width operation, the construction of the tube becomes-more difiicult and requires a high degree of care in the accuracy of the assembly.

It is one of the objects of this invention to provide a radio frequency coupling by means of Microstrip transmission line through the envelope of electron discharge devices.

Another object of the invention .is to provide a socket arrangement for coupling radio frequency transmission lines, and other electric circuits where desired, to corresponding terminals extending through the envelope of electron discharge devices.

Another object is to provide a Microstrip type of transmission line coupler for use in coupling radio frequency energy into electron discharge devices and to provide menas for coupling direct current potential to the Microstrip coupler in isolation to the radio frequency input connection thereto.

One of the features of the invention is the employment of a relatively simple, inexpensive microwave printed circuit form of R.-F. transmission line for the transition sections between high and low impedance lines. To obtain good impedance match the printed line is prefer ably of the type disclosed in my joint copending application with P. Parzen, Serial No. 286,764, filed May 8, 1952, now Patent No. 2,774,046. A typical printed R.-F. line such as disclosed in this copending application comprises a pair of strip conductors wherein the first conductor is in the form of a wide strip having a planar surface over which a second narrower strip conductor is disposed by dielectric material in closely spaced, substantially parallel relation. The conductor spacing is usually increased where the conductors leave the dielec-' tric material and extend through the glass seal since the dielectric constant of the glass is larger than the dielectric constant of the dielectric material of the-R.-F. line. In tube constructions where such Microstrip lines are used within the envelope the conductors of -thelines protrucling from the. envelope are preferably tapered-to'form .2. terminal pins for reception in suitable socket arrangements.

Another feature of "the invention is the provision of a socket for transition of radio frequency energy from a coaxial line toa Microstrip configuration for coupling to tube terminals which in turn are preferably connected or form an integral'part of a Microstrip transition section Within the tube. The socket may also include other leads such as potential and power leads for such electrodes as the. cathode and accelerator electrodes. Still another feature of the invention is: the provision in the Microstrip coupling-section of means for applying to the electrode couple thereto of a D. C. potential while isolating said D. C. potential from the radio frequency source coupled to the Microstrip section.

The above-mentioned and other features and objects of this invention and the manner of attaining them will becomemore apparent by reference to the following description taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional view of the input end portionof a traveling wave tube and an input socket member coupled thereto;

Fig. 2 is a fragmentary sectional view taken along line z 2 of Fig. 1;

Figs. 3 and 4 are cross-sectional views taken along lines 3-3 and 44 of Fig. 1; and

Fig. 5 is a longitudinal sectional view of a modified form of D. C. isolation coupler that may be employed in the Micros-trips line. v

Referring particularly to Fig. l the input end of the traveling wave tube 1 is shown coupled to an input socket member 2. The traveling wave tube 1 includes a radio frequency (R.-F.) helical line 3 and an electron beam forming structure 4, the two parts 3 and .4 being so disposed that the beam path is axially of the helical conductor 3 whereby an interaction is obtained between the electrons of the beam and the electromagnetic field formed by R. F. energy propagated'along the helical line. It will be understood, however, that the envelope of the tube 1 is of sufiiciently small diameter as to permit re.- ception of a solenoid or a permanent magnet structure thereabout for the establishment of a magnetic field axially of the helical line for the purpose of maintaining the electron beam axially of thehelical line.

.The gun structure 4 includes a'cathode 5, a focusing electrode 6 and an accelerating electrode 7. While the focusing electrode is shown as a part of a cavity resonator 8, it may be otherwise formed as will be obvious to those skilled. in the art. The output coupling to the helical line and the electron collector have not been shown since such showing is believed unnecessary to an understanding of thisinvention. It should also be understood that the. helical line-electron gun structure may be varied considerably from the embodiment shown, the electron beam, for example, may be of annular cross-section and caused to flow concentrically-of the helical line.

Referring to Figs. 1, 2 and 3, the coupling to the helical line 3 is shown to comprise a Microstrip line having a first or planar conductor 9, a layer of dielectric 10, either of ceramic or other suitable high temperature material, and a. second or line conductor 11, 110. The. line conductor 11, .110 which ispreferably of strip configuration is tapered doWn to the diameter of. the helical,

conductor to which it is connected, as shown in Figs.

1 and 2. The manner of coupling may take several forms certainof which are disclosed in mycopen'dingapplica- 1 transition of the'low impedance of the Microstrip section to the high impedance of the helical line. The conductors 9 and 110 are spread apart and extended through the envelope 13 to which they are sealed, the outer ends 14 and 15 of conductors 9 and 110 being in the form of terminal pins for reception in socket member 2.

While I show the line 11 connected through an impedance transition 12 to high impedance line 3 it may, of course, be coupled directly to an electrode without requiring the impedance transition 12. Such a direct coupling is shown for line 18.

The R.-F. Microstrip coupling section for the cavity resonator 3 is similar to that for the helical line 3 in that it comprises a planar conductor 16, dielectric layer 17 and a strip conductor 18. The conductor 16 is connected to the wall of the cavity resonator and the strip conductor is extended in the form of a loop 19 into the cavity of the resonator. The

conductors

16 and 18 extend through the envelope 13 as terminal pins 24} and 21, respectively. If desire-d, planar conductors 9 and 16 may be formed integral as a hollow cylinder similar to the cylindrical conductor 28, thus adding rigidity and shielding for the electrodes of the gun structure.

In addition to the R.-F. coupling lines other leads, such as electrical connections for the cathode and accelerator electrodes, and also to furnish D.-C. bias if desired for the helical line, may be provided by the same socket member. In this connection I have shown

additional terminals

22 and 23, (Figs. 1, 3 and 4) connected to the cathode 5, terminal 24 connected to accelerator electrode 7 and terminal 25 to provide D.-C. potential for the helical line or other terminals as the case may be. the embodiment shown, the strip conductor 11, 110 is provided with a V-shaped gap 26 which is capable of coupling R.-F. energy along the Microstrip section while providing D.-C. isolation for the source of R.-F. energy coupled to the section. As indicated in Figs. 1 and 2, DC. potential from terminal 25 is connected to the strip 11 by a small lead 27 which presents a high impedance acting as an R.-F. choke to the R.-F. energy propagated along the Microstrip section. The distance D from the connection of lead 27 and the gap 26 is so selected that the susceptance thereof is of sufficient value to tune out any impedance mismatch present in the pin coupling through the envelope.

In Fig. a modified form for D.-C. potential coupling is shown. In this form the planar conductor is shown as 9a, the strip conductor is 11a and the D.-C. coupling lead as 27a. The gap comprises a parallel section 26a formed between the strip 11a and a terminal strip 1115. As shown the terminal portion 11b. is disposed in overlapped spaced relation to an end portion of strip 11a, the dielectric material 190 being shaped to properly space the parts. While the two strip portions 11a and 11b are shown in overlapping relation they may, of course, be disposed in an overlapped or side-by-side relation in the same plane parallel to the planar conductor 9a.

Referring back to Figs. 1, 3 and 4, the socket member 2 is shown to comprise a hollow cylindrical conductor 28 to which two

coaxial line couplers

29 and 31 are coupled, the outer conductor 31 of each being connected directly to the cylindrical conductor 28 while the inner conductor 32 is extended through an opening 33 to the interior of the hollow conductor 28. A line conductor 34 preferably of strip form is disposed in parallel spaced relation to the inner wall surface of the cylindrical conductor 28 to form in effect a Microstrip transmission line. One end of the strip is connected to the inner conductor 32 while the other end is provided with a socket 35 for reception of one of the tube terminals, such as terminal 21. The cylindrical conductor is likewise provided with a socket receptacle as indicated at 36 and 37 to receive the terminal pins 29 and 14. In addition to the coaxial line couplers additional electrical leads may be provided through the socket member 2 as indicated at 38 and which are similarly provided with receptacles for receiv- 4 ing terminal pins as indicated at 39. The socket member may be provided with dielectric material 49 to fill in the spaces between the conductors for proper positioning thereof.

From the foregoing description it will be clear that a relatively simple and quick coupling arrangement is provided for the coupling of one or more sources of radio frequency energy as well as other electrical sources to the electrodes of a traveling wave tube or other electron discharge device employing more than one type of current. In the present embodiment the traveling Wave tube is provided with all of its input terminals at one end of the envelope to which the socket is applicable so as to apply the electrical energies required. A similar socket may be provided for the output terminals at the other end of the tube although the output will have a smaller number of terminals.

While I have described above the principles of my 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 of my invention, as set forth in the objects thereof and in the accompanying claims.

I claim:

1. In an electron discharge device having an envelope enclosing an electrode to which radio frequency coupling must be had through said envelope, a radio frequency coupler contained within said envelope, said coupler comprising first and second conductors one of which is coupled to one of said electrodes, dielectric means disposed to maintain said conductors in closely spaced substantially parallel relation, said first conductor being wider than said second conductor and having a planar surface over which said second conductor extends, and said first and second conductors being terminated in the form of terminal pins extending through and in sealed relation to said envelope.

2. An electron discharge device according to claim 1, wherein said second conductor is the one coupled to said electrode and which is of fiat strip form having a direct current isolating gap therein, said gap being narrow so as to couple radio frequency energy thereacross.

3. An electron discharge device according to claim 2, wherein the gap forming portions of said second conductor are shaped to form diagonally disposed gap portions.

4. An electron discharge device according to claim 2, wherein the conductor portions of said second conductor forming said gap are disposed in parallel spaced overlapping relation.

5. An electron discharge device according to claim 1, wherein said second conductor has a direct current isolating gap therein, the conducting portions forming said gap being disposed in adjacent parallel spaced relation, and means coupling a direct current potential to said second conductor on one side of said gap.

6. In combination, an electron discharge device having an envelope through which radio frequency coupling must be had, a radio frequency coupler contained Within said envelope, said coupler comprising first and second conductors, means disposing said conductors in closely spaced substantially parallel relation, said first conductor being wider than said second conductor and having a planar surface over which said second conductor extends, said first and second conductors being terminated in the form of terminal pins extending through and in sealed relation to said envelope, and coupling means outside of said envelope for coupling a radio frequency transmission line to said terminal pins, said coupling means including a socket member having a hollow conductive cylindrical member, a coaxial coupling comprising an outer conductor connected to said cylindrical member and an inner conductor extending through an opening in said cylindrical member to the interior thereof, a line conductor coupled to said inner conductor and disposed in parallel spaced relation to the inner wall surface of said cylindrical conductor to form in conjunction therewith a parallel two conductor waveguide, and means at one end of said cylindrical member to conductively couple said pins to said cylindrical member and said line conductor, respectively. I

7. In combination, an electron discharge device having an envelope through which radio frequency coupling must be had, a radio frequency coupler contained within said envelope, said coupler comprising first and second conductors, means disposing said conductors in closely spaced substantially parallel relation, said first conductor being wider than said second conductor and having a planar surface over which said second conductor extends, said first and second conductors being terminated in the form of terminal pins extending through and in sealed relation to said envelope, and coupling means outside of said envelope for coupling a radio frequency transmission line to said terminal pins, said second conductor having a direct current isolating gap therein, the conducting portions forming said gap being disposed in adjacent parallel spaced relation, a lead of high impedance acting as a choke to radio frequency energy connected to said second conductor on one side of said gap, said lead being terminated in a third pin disposed through said envelope adjacent the first mentioned pins and said coupling means having means to couple a direct current potential to said third pin.

8. The combination according to claim 7, wherein the connection of said lead to said second conductor is located a selected fraction of a wavelength of the mid operating frequency of said radio frequency to provide a susceptance of sufiicient value to tune out any impedance mismatch present in the pin coupling through said envelope.

9. In combination, an electron discharge device having an envelope enclosing first and second electrodes to which radio frequency coupling must be had, a radio frequency coupler for each of said electrodes, each said coupler being contained in said envelope and comprising first and second conductors, means disposing said conductors in closely spaced substantially parallel relation, said first conductor being wider than said second conductor and having a planar surface over which saidsecond conductor extends, said first and second conductors being terminated in the form of terminal pins extending through and in sealed relation to said envelope, and coupling means outside of said envelope for coupling a radio frequency transmission line to said terminalpins, said coupling means comprising a socket member having a hollow conductive cylindrical member, a pair of coaxial couplings to provide radio frequency energy for said first and second electrodes, each coaxial coupling having an outer conductor connected to said cylindrical member and an inner conductor extending through an opening in said cylindrical member to the interior thereof, a pair of line conductors each being coupled to one of the inner conductors of said coaxial couplings and disposed in parallel spaced relation to the inner wall surface of said cylindrical conductor to form in conjunction therewith a parallel two conductor waveguide, said cylindrical member and each of the line conductors having sockets to receive the said pins extending through said envelope.

10. A radio frequency coupler for electron discharge devices comprising a hollow conductive cylindrical member, a coaxial coupling having an outer conductor connected to said cylindrical member and an inner conductor extending through an opening in said cylindrical member to the interior thereof, a line conductor coupled to said inner conductor and disposed in parallel spaced relation to the inner wall surface of said cylindrical conductor to form in conjunction therewith a parallel two conductor waveguide, said cylindrical member and said line conductor each having sockets to receive terminal pins of said electron discharge device.

11. A radio frequency coupler for coupling radio frequency energy to first and second electrodes of an electron discharge device having terminal pins for said electrodes protruding through the envelope thereof, comprising a hollow conductive cylindrical member, a pair of coaxial couplings to provide radio frequency energy for said first and second electrodes, each coaxial coupling having an outer conductor connected to said cylindrical member and an inner conductor extending through an opening in said cylindrical member to the interior thereof, a line conductor coupled to each of the inner conductors of said coaxial couplings, each of said line conductors being disposed in parallel spaced relation to the inner wall surface of said cylindrical conductor to form in conjunction therewith a parallel two conductor waveguide, said cylindrical member and each of the line conductors having sockets to receive the said pins extending through said envelope.

12. In combination, an electron discharge device having an envelope through which both direct current and radio frequency coupling must be had, a plurality of direct current leads contained within said envelope to carry direct current potential to certain ones of the electrode of said discharge device terminated in terminal pins extending through and in sealed relation to said envelope, a radio frequency coupler contained within said enevelope comprising first and second conductors, means disposing said conductors in closely spaced substantially parallel relation, said first conductor being wider than said second conductor and having a planar surface over which said second conductor extends, said first and second conductors being terminated in the form of terminal pins extending through and in sealed relation to said envelope, and coupling means outside said envelope for coupling a radio frequency transmission .line to the radio frequency coupler terminal pins and direct current conductors to the direct current terminal pins, said coupling means including a socket member having a hollow conductive cylindrical member, a plurality of direct current conductors disposed in said cylindrical member, means at one end of said cylindrical member to conductively couple said direct current terminal pins to said direct current conductors, a coaxial coupling comprising an outer conductor connected to said cylindrical member and an inner conductor extending through an opening in said cylindrical member to the interior thereof, a line conductor coupled to said inner conductor and disposed in parallel spaced relation to the inner wall surface of said cylindrical conductor to form in conjunction therewith a parallel two-conductor waveguide, and means at said one end of said cylindrical member to conductively couple the terminal pins of said first and second conductors of said radio frequency coupler to said cylindrical member and said line conductor, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 1,700,832 Drake Feb. 5, 1929 1,936,069 Reid Nov. 21, 1933 2,000,570 Nina May 7, 1935 2,160,478 Laico May 30, 1939 2,391,927 Segerstrom Jan. 1, 1946 2,407,974 Clifford et al. Sept. 24, 1946 2,434,509 Okress Jan. 13, 1948 2,451,413 Robinson Oct. 12, 1948 2,654,842 Engelmann Oct. 6, 1953 2,716,202 Little Aug. 23, 1955 2,740,068 Robertson Mar. 27, 1956 OTHER REFERENCES Article by J. A. Kostriza, Proc., 1. R. E., vol. 40, pp. 1658-1663, December 1952.