JPS62131Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to improvements in traveling wave tubes.

In general, a straight beam microwave tube uses an electron beam to amplify and oscillate microwaves, and a typical type of tube is a traveling wave tube.

A traveling wave tube is conventionally configured as shown in Figure 1.
It consists of an electron gun 1, a slow wave circuit 2, and a collector 3. As is clear from FIG. 2, the slow wave circuit 2 has a helix 5 coaxially accommodated within a metal cylindrical envelope 4 and supported by three dielectric supports 6. In addition, 7 in the figure is a high frequency signal input section,
8 is a high frequency signal output section.

By the way, in the conventional traveling wave tube having the above structure, during operation, the electrons emitted from the cathode of the electron gun 1 are formed into a predetermined electron beam by a beam shaping electrode, and this electron beam is passed through the slow wave circuit 2. However, an attenuator must be provided around the helix 5 to prevent local oscillation. Conventionally, therefore, a carbon resistance layer having a partial attenuator structure is formed on the dielectric support 6 and used as an attenuator, but a sufficient effect has not been obtained.

This invention was developed in view of the above circumstances, and the object thereof is to provide a beam-straight microwave tube that can sufficiently prevent local oscillation and perform high frequency amplification extremely stably.

Hereinafter, one embodiment of this invention will be described in detail with reference to the drawings.

The slow wave circuit in the traveling wave tube of this invention is constructed as shown in FIGS. 3 and 4. That is,
A helix 10 is disposed coaxially within a metal cylindrical envelope 9 and is supported and fixed by three dielectric supports 11 . In this case, the dielectric support 11 is shaped like a rod and has a substantially quadrilateral cross section with stepped portions 11a and 11b, and the side in contact with the inner surface of the envelope 9 (the side opposite to the stepped portions 11a and 11b) is formed into a curved surface. has been done. Three such dielectric supports 11
A total of three high frequency attenuators 12 are arranged between the two in the tube axis direction. This high frequency attenuator 12
For example, it is made of ceramic porcelain or bearing porcelain with a carbon resistance layer distributed thereon, or a sintered carbon resistor whose length and resistance value are changed according to desired characteristics, and has a circular cross section as shown in Figure 5. It is formed into an arc shape with both ends tapered, and its inner surface is in contact with the helix 10, and both ends are located at the stepped portions 11a and 11b of the dielectric support 11. In other words, step part 1
The high frequency attenuator 12 is pressed against the helix 10 by 1a and 11b. Incidentally, the envelope 9 and the dielectric support 11, and the dielectric support 11 and the helix 10 are fixed by brazing or contact holding.
Moreover, since the traveling wave tube of this invention is the same as that shown in FIG. 1 except for the slow wave circuit, detailed explanation will be omitted.

The traveling wave tube of this invention is constructed as described above and illustrated, and the high frequency attenuator 12 is disposed between the three dielectric supports 11, so that high frequency amplification can be carried out extremely stably. Suitable for high power applications. Moreover, the high frequency attenuator 1 in this invention
2 can be arbitrarily selected at a position where the reflection coefficient is small.
Furthermore, since the amount of attenuation can be freely selected by selecting the shape, this is significant in terms of manufacturing, especially in the process of assembling the helix 10.

In the above embodiment, the helix 10 was supported at three points, that is, three dielectric supports 11 were used.
As shown in Figures 6 and 7, four-point support, that is, four
dielectric supports 13 may be used. In this case, the four dielectric supports 13 are located in the cross direction, and therefore the high frequency attenuators 14 are also located between the dielectric supports 13, so a total of four high frequency attenuators 14 are required. This high frequency attenuator 14 is the eighth
As is clear from the figure, it is a round rod with both ends tapered. Also, it is pressed in the direction of the helix 10 by the stepped portions 13a and 13b of the dielectric support 13.

Further, although the dielectric supports 11 and 13 in the above embodiments and modified examples were each formed with tapered ends, as shown in FIGS. Support 1
5, 16 may also be used.

As explained above, according to this invention, a traveling wave tube of great industrial value can be provided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional traveling wave tube and a traveling wave tube used to explain this invention, Fig. 2 is a sectional view showing the main part (slow wave circuit) in a conventional traveling wave tube, and Fig. 3 is a sectional view of this invention. A sectional view showing the main part (slow wave circuit) of a traveling wave tube according to an embodiment, FIG. 4 is A of FIG.
A cross-sectional view taken along the −A′ line and viewed in the direction of the arrow,
FIG. 5 is a perspective view showing the high frequency attenuator used in the embodiment of FIG. 3, FIG. 6 is a sectional view showing a modification of this invention, and FIG. FIG. 8 is a perspective view showing a high-frequency attenuator used in a modification of FIG. 6, and FIGS. 9 and 10 are perspective views showing modifications of the high-frequency attenuator. . 9... Envelope, 10... Helix, 11...
Dielectric support body, 11a, 11b... step part, 12...
...High frequency attenuator.

Claims (1)

[Scope of utility model registration request] A helix is arranged coaxially within a cylindrical envelope,
In a traveling wave tube that is supported and fixed by a plurality of dielectric materials, each of the dielectric supports is provided with a stepped portion, and a high frequency attenuator is further provided between each of the dielectric supports, and the stepped portion is utilized. A traveling wave tube characterized in that the high frequency attenuator is pressed in the direction of the helix.