JPH01276539A - Traveling-wave tube - Google Patents

Abstract

PURPOSE:To prevent the propagation of unnecessary modes and facilitate assembling by surrounding and holding three helix support bars made of a dielectric substance with a supporter having an inward spring action. CONSTITUTION:Three helix support bars 6 made of a dielectric substance are surrounded by a supporter 8 having an inward spring action and kept in contact with the inner face of a vacuum envelope 4, a heat conducting plate 9 made of a conductor is provided between the adjacent helix support bars 6 and the vacuum envelope 4 directly or via the supporter 8. The heat conducting plate 9 is only required to be inserted into the pipe-shaped vacuum envelope 4 together with the supporter 8 along its linear section, the inner space of the vacuum envelope 4 is shrunk by the supporter 8 and the heating conducting plate 9. This device is relatively easily assembled, the propagation of unnecessary modes can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to traveling wave tubes 1, and particularly to improvements in slow wave circuits thereof.

(Prior Art) Traveling wave tubes generally use electron beams to amplify and oscillate microwaves. Conventional traveling wave tubes are configured as shown in Fig. 2, with an electron gun 1 , slow wave circuit 2
and a collector 3. The slow wave circuit 2 is
As is clear from FIG. 3, a plurality of helices 5 are supported and fixed inside the pipe-shaped vacuum envelope 4 by a plurality of, for example, three helix support rods 6 made of dielectric material. Note that 10 in FIG. 2 is a high frequency input section, and 11 is a high frequency output section.

During manufacturing, the helix 5 is assembled so as to be evenly supported by a plurality of, for example, three dielectric helix support rods 6, and the circumscribed radius is designed to be slightly thicker than the inner diameter of the vacuum envelope 4. There is. Therefore, the vacuum envelope 4
By applying and maintaining uniform arbitrary pressure from three directions around the outer circumference, the cross section of the vacuum envelope 4 becomes triangular. When the assembled helix 5 and the three dielectric helix support rods 6 are inserted into the vacuum envelope 4 and the pressure from the three directions of the outer periphery is released, the elasticity of the vacuum envelope 4 causes the helix 5 to And the three dielectric helix support rods 6 are mechanically supported.

By the way, in the above-mentioned slow wave circuit 2, it is easy to form a coaxial tube in which the helix 5 is the inner conductor and the vacuum envelope 4 is the outer conductor, and the coaxial mode propagates, so there is no way to remove this coaxial mode. It will be done. An example of this method is
As described in Japanese Patent No. 7-50955, there is one in which a metal piece is provided between three dielectric helix support rods.

(Problem to be solved by the invention) However, in the configuration described in the above publication, 3
In addition to the dielectric helix support rod, three metal pieces must be aligned in predetermined positions and inserted into the vacuum envelope in the form of a vibrator, making assembly extremely difficult. Therefore, each part is easily deformed, and it is not easy to manufacture a traveling wave tube with good characteristics.

An object of the present invention is to provide a traveling wave tube that has a structure that can be assembled relatively easily and that can suppress propagation of unnecessary modes.

[Structure of the Invention (Means for Solving the Problems) This invention provides a structure in which a plurality of dielectric helix support rods are surrounded by a support member having an inward spring action and in contact with the inner surface of a vacuum envelope; This is a traveling wave tube in which a heat transfer plate made of a conductor is provided between adjacent helix support rods and a vacuum envelope, either directly or via a support.

(Function) According to the present invention, since the helix and its helix support rod are mechanically held by the substantially triangular support having an inward spring action, the heat transfer plate is attached to the straight portion of the support. They can be easily assembled by simply inserting them together into a vibrator-like vacuum envelope. Since the inner space of the vacuum envelope is effectively reduced by the support and the heat transfer plate, propagation of unnecessary modes is prevented and stable operating characteristics are obtained.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings, but since this invention is an improved slow-wave circuit of a traveling wave tube, only the slow-wave circuit will be described. do.

That is, the slow wave circuit according to the present invention is constructed as shown in FIG. This helix 5 is supported and fixed by a plurality of, for example, three dielectric helix support rods 6.

In this case, three dielectric helix support rods 6 are surrounded by a support 8. This support 8 is made of a non-magnetic material such as molybdenum or Inconel, has a triangular cross section with a gap 8a, is set to a predetermined length, has an inward spring action as shown by the arrow, and has a vacuum surrounding. It is in contact with the inner surface of container 4. In other words, it has a spring action that causes the diameter to contract.

Furthermore, a heat transfer plate 9 made of a conductive material is provided along the outer periphery of the support 8, that is, along each approximately linear side of the triangular cross section. This heat transfer plate 9 is made of, for example, a copper plate, and both end surfaces are in surface contact with the inner surface of the vacuum envelope 4 and also in contact with the helix support rod 6, serving both as heat radiation and prevention of unnecessary mode propagation. There is a space between the heat transfer plate 9 and the inner surface of the vacuum envelope 4.

Note that this heat transfer plate 9 and support body 8 are not brazed. Further, the support body 8 and the vacuum envelope 4 are also not brazed.

Further, since the traveling wave tube of the present invention has the same structure as the conventional example (FIG. 2) except for the slow wave circuit described above, detailed explanation will be omitted.

(Other Embodiments) The support body 8 does not have to be provided over the entire slow wave circuit, but may be provided only on the input section 10 side and the output section 11 side.

The portion where the support body 8 does not exist is a heat transfer plate 9
is provided in direct contact with the helix support rod 6 to prevent the propagation of unnecessary modes.

Further, the support body 8 may be divided in the tube axis direction and arranged alternately with the heat transfer plates 9. In that case, the heat transfer plates 9 are arranged between the adjacent helix support rods 6 and the vacuum envelope 4. will be established directly.

[Effects of the Invention] According to the present invention, the three dielectric helix support rods are surrounded and held by the support having an inward spring action, thereby preventing the propagation of unnecessary modes. It is easy to assemble, and there are almost no problems such as changes in the pitch of the helix.

[Brief explanation of the drawing]

FIG. 1 is a radial sectional view showing the main part (slow wave circuit) of a traveling wave tube according to an embodiment of the present invention, FIG. 2 is an axial sectional view showing the entire conventional traveling wave tube, and FIG. The figure is a radial cross-sectional view showing an example of a slow wave circuit in a conventional traveling wave tube. 4... Vacuum envelope, 5... Helix, 6... Helix support rod, 8... Support body, 9... Heat transfer plate. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a traveling wave tube equipped with a slow wave circuit in which a helix is supported and fixed by a plurality of dielectric helix support rods inside a pipe-shaped vacuum envelope, the plurality of dielectric helix support rods are It is surrounded by a support that has a spring action and is in contact with the inner surface of the vacuum envelope, and is further provided with a conductive conductor between the adjacent helix support rod and the vacuum envelope, either directly or through the support. A traveling wave tube characterized in that it is provided with a heat plate.