JP2679378B2 - Spiral slow wave circuit structure - Google Patents

Description

The present invention relates to a spiral slow wave circuit structure used in a traveling wave tube or the like.

[Conventional technology]

As an envelope for a spiral slow-wave circuit, there is an envelope in which disk-shaped magnetic poles and cylindrical metal spacers are alternately laminated and brazed and joined. When this envelope is used, since the inner diameter of the magnetic pole is closer to the spiral housed in it, a higher central magnetic flux density can be obtained even if the energy of the annular half permanent magnet combined with the magnetic pole is the same. Therefore, in a traveling wave tube having a high frequency and higher efficiency, the slow wave circuit configured as described above has been adopted.

FIG. 3 shows a cross-sectional view of a conventional slow wave circuit structure 20,
The drawing shows a cross-sectional view taken along the line BB in FIG. 3, but the spiral 1 is housed in an envelope 5 in which three dielectric support columns 2, 3, 4 are arranged around the outer periphery thereof. The envelope 5 is formed by alternately combining and joining discoid magnetic poles 6 and nonmagnetic cylindrical metal spacers 7. Disc-shaped shield parts 10 and 11 for joining the collector 8 and the electron gun 9 are provided at both ends of the envelope 5, and high-frequency windows 12 and 13 for inputting and outputting high-frequency waves are arranged in the vicinity of the parts to delay waves. The envelope 5 for the circuit is configured. Envelope 5
After the disk-shaped magnetic pole 6, the cylindrical metal spacer 7, the disk-shaped shield parts 10 and 11 and the input and output high-frequency windows 12 and 13 are joined by brazing, etc., the spiral 1 and 3 dielectric support columns 2,3,4
Forming and cutting of the hole for housing is performed. This is because the spiral 1 and the dielectric columns 2, 3 and 4 are inserted and fastened by shrink fitting, so the fastening allowance is set to an appropriate value and the hole This is because it is necessary to remove the irregularities on the inner peripheral surface and finish it into a mirror surface. The hole cutting allowance is generally 0,2 to 0,3 mm, and a gun drill is used for cutting. The length of the slow wave circuit 5 in the axial direction varies depending on the product, but when the circuit becomes long, it is a split type, so the length of one circuit is generally around 100 mm.
In addition, a shield component 10 for joining the electron gun 9 is provided on the electron gun 9 side.
It is often the case that the input high-frequency window 12 is disposed at the fifth annular half magnet (not shown). Speaking of the disk-shaped magnetic pole 6, an input high frequency window is provided on the cylindrical metal spacer 7 between the shield component 10 and the fourth and fifth magnetic poles. this is,
The passband characteristic of the traveling wave tube causes a temporary increase in the spiral current at start and stop, but at this time, most of the electron beam emitted from the electron gun is concentrated on the input side of the circuit, so spiral 1 is the electron beam. In order to avoid the damage caused by the collision, the starting point of spiral 1 is shifted as described above. A beam cutter 18 made of a cylindrical metal having a high melting point, such as molybdenum, having an inner diameter equal to that of the helix 1 is arranged in that portion.

Therefore, the envelope 5 becomes longer than the length of the slow wave circuit. In the envelope 5, after the hole is cut by a gun drill, a spiral and three dielectric support columns 2, 3, 4 are inserted and fastened and fixed in the hole by a firing spring method. Both ends of the spiral 1 are respectively joined to the central axis conductors 14 and 15 of the input and output high frequency windows 12 and 13 to form a slow wave circuit structure 20. A collector 8 is connected to the output end of the slow-wave circuit structure 20, and an electron gun 9 is connected to the input end of the slow-wave circuit structure 20 and shield components 10 and 11 at the circuit end to form a traveling wave tube. The collector 8 and the electron gun 9 are designed so that the enclosing pans 16 and 17 at their joint ends and the shield parts 10 and 11 are fitted to each other to obtain a desired concentricity.

[Problems to be solved by the invention]

In this conventional slow wave circuit structure 20, the axial length is 10
The length is 0 to 150 mm, and it is necessary to further cut the hole at the center of the hole, mirror finish the inner peripheral surface, and perform ultra-precision processing to control the inner diameter in units of microns. For this reason, cutting is performed with a gun drill, but depending on the hole diameter, considerable bending occurs. Since this bend is a gentle bend between the input and the output, it does not cause any particular problem in focusing the electron beam, and good beam transmission characteristics can be obtained. However, in connecting the electron gun 9 to the slow wave circuit structure 20, It becomes a serious problem. When centering is performed with the shield component 11 at the output end as a reference and the gun end is cut in the direction of the input end, the eccentricity with the shield component 10 at the input end becomes a considerably large number. Therefore, the electron gun 9 is designed so that the center of the slow wave circuit structure 20 can be obtained by mutual fitting of the enclosing tray 16 at the joint end and the shield component 10.
Depending on the eccentricity with respect to 10, the center of the electron gun 9 and the center of the hole of the slow wave circuit structure 20 naturally deviates by about the same amount. This deviation seriously affects the conditions under which the electron beam from the electron gun 9 enters the slow-wave circuit structure 20 and causes deterioration of the beam transmission characteristics, which impedes normal operation.

[Means for solving the problem]

The slow-wave circuit structure of the present invention independently forms a slow-break circuit main body and an input-port magnetic pole assembly divided by an arbitrary magnetic pole portion between the input-side high-frequency window and the input-end shield component, and spiral and dielectric. After inserting the body support into the slow wave circuit, the slow wave circuit and the magnetic pole assembly of the input portion are fitted by brazing or the like to form a slow wave circuit structure.

〔Example〕

The present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a tube using a slow wave circuit structure according to an embodiment of the present invention,
FIG. 2 is a sectional view taken along line AA of FIG. Slow wave circuit structure 41
Is divided into two blocks, a slow wave circuit 31 and an input magnetic pole assembly 32. The envelope 34 of the slow wave circuit has the disk-shaped magnetic pole 6, the cylindrical metal spacer 7, the high-frequency windows 12 and 13 for input and output, the shield component 11 at the output end, and the magnetic pole 33 at the junction on the input side. It is formed by being attached. The junction magnetic pole 33 is configured to be the second magnetic pole from the input side high frequency window 12. Then, after cutting the center hole of the envelope 34, the spiral 1 and the three dielectric columns 2, 3, 4 are inserted into the center hole of the envelope 34 by shrink fitting and fastened and fixed. After that, the ends of the spiral 1 are joined to the central axis conductors 14 and 15 of the input and output high frequency windows 12 and 13, respectively, to form a slow wave circuit 31.

On the other hand, the input magnetic pole assembly 32 includes one joint magnetic pole 33, two disc-shaped magnetic poles 6, three cylindrical metal spacers 7 and one shield component 10, which are brazed together. .
Then, the inner diameter is machined in the same manner as the center hole of the envelope 34 of the slow wave circuit, and then the beam cutter 18 is disposed and formed. Each of the junction magnetic poles 33 is approximately 1 / thick of the thickness of the disk-shaped magnetic pole 6.
2

The slow wave circuit 31 and the input magnetic pole assembly 32 formed in this manner are joined to each other at their joint magnetic poles 33 and joined by high-frequency brazing or the like. At this time, brazing is performed through an appropriate mandrill to match both centers. In this way, the slow wave circuit structure 41 is formed.

When cutting is performed with the center of the shield component 11 at the output end of the envelope 34 as a reference, a considerable eccentricity occurs with the shield component 10 at the input end. On the other hand, when the axial length of the input magnetic pole assembly 32 is about 10 mm, the inner diameter, the prepared hole and the machining allowance are the same as those of the envelope 34, the eccentricity between the input shield 10 and the joint magnetic pole 33 and the center hole after cutting is It can be processed within an acceptable range.
These are butt-joined to each other through the appropriate magnetic mandrel to join the magnetic poles 33 of the joint portion, so that the electron gun 9 and the slow wave circuit structure
The concentricity with 41 can be improved.

〔The invention's effect〕

As described above, the present invention is configured by forming the magnetic pole assembly on the input side partially independently, and then joining the slow wave circuit and the centers of the helix and the beam cutter so that their centers match each other. It is a slow wave circuit structure. Therefore, since good concentricity with the electron gun can be secured, there is an effect that the beam transmission characteristics are further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a tube of an embodiment of the present invention, and FIG.
3 is a sectional view taken along line AA of FIG. 3, FIG. 3 is a sectional view of a tube using a conventional slow wave circuit structure, and FIG. 4 is a sectional view taken along line BB of FIG. 1 ... helix, 2,3,4 ... dielectric support, 5,3,4 ... enclosure, 6 ... disc-shaped magnetic pole, 7 ... cylindrical metal spacer, 8
…… Collector, 9 …… Electron gun, 10,11 …… Disc-shaped shield parts, 12,13 …… High frequency window, 14,15 …… Center axis conductor, 1
6,17 …… Enclosure tray, 18 …… Beam cutter, 20,41 …… Slow wave circuit structure, 31 …… Slow wave circuit, 32 …… Input part magnetic pole assembly, 33
...... Joint magnetic pole.

Claims (1)

(57) [Claims] 1. A disk-shaped shield component for alternately connecting an output-side high-frequency window and a collector, wherein disk-shaped magnetic poles and cylindrical metal spacers are alternately laminated and fixed, and an input-side high-frequency window is provided at the other end. And a slow wave circuit having a spiral and a plurality of dielectric struts in an envelope having a junction magnetic pole, a disk-shaped magnetic pole and a cylindrical metal spacer are alternately laminated and fixed, and an electron gun is attached to one end. An input side magnetic pole assembly having a disc-shaped shield component to be joined and a junction magnetic pole at the other end, and the joining magnetic poles of the slow wave circuit and the input side magnetic pole assembly are joined together. Swirl type slow wave circuit structure.