JPH0449806Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a support structure for a high-frequency circuit of a helical traveling wave tube using a periodic permanent magnet (hereinafter referred to as PPM) as an electron beam focusing device.

[Conventional technology]

As is well known, a helical traveling wave tube has a relatively simple high-frequency circuit structure and a relatively small outer diameter, which makes it easy to focus electron beams using PPM. However, since the overall length of the high frequency circuit is long compared to its outer diameter and its mechanical strength is low, it is necessary to support the high frequency circuit in some way. Various ideas have been made for support structures for high-frequency circuits using helical traveling wave tubes, one example of which is shown in FIGS. 3 and 4.

[Problem that the invention aims to solve] In the figure, 1 is an electron gun, 2 is a high frequency circuit section and
3 is a collector section, 4 is a case substrate forming a part of the case, 5 is a high frequency circuit support body, and 6 is a presser plate. The high-frequency circuit support 5 receives the lower part of the PPM along the tube axis direction over almost the entire length at its curved part, and the holding plate 6 is made of a thin plate (approximately 0.1 to 0.5 mm) of non-magnetic metal with a large elastic modulus in an Ω-shape. It has a shaped structure, and is mounted by sandwiching the PPM within the elastic range of the material, and is firmly fixed with screws 7. This structure is characterized in that the high-frequency circuit has extremely high mechanical strength because it supports the high-frequency circuit almost throughout the tube axis direction. but,
In a high-power helix-shaped traveling wave tube, heat generation on the output side of the helix increases due to the high-frequency loss of the helix, and the high-frequency circuit and PPM become quite hot.
The heat generated by the helix is transferred to PPM from the vacuum envelope.
Furthermore, the case substrate 4 is connected via the high frequency circuit support 5.
It cannot be said that the cooling effect is sufficient just by allowing the conduction to occur. Therefore, mechanical deformation due to thermal expansion of the high-frequency circuit, a decrease in the magnetic field of the PPM due to thermal demagnetization, and an increase in high-frequency loss due to the high temperature of the helix cause deterioration of beam transmission characteristics and a decrease in high-frequency output, resulting in high It had the disadvantage of limiting output.

[Means for solving problems]

The present invention provides high-frequency circuit support in a traveling wave tube consisting of an electron gun section, a high-frequency circuit section equipped with a PPM, and a collector section, in which the high-frequency circuit section is supported and fixed along the tube axis by a support and a presser plate. It is characterized by a plurality of cooling fins extending along the tube axis direction on the back side of the body, and holes provided on the case substrate to serve as passages for cooling air to achieve effective cooling.

〔Example〕

The present invention will be explained with reference to the drawings. 1st
The figure is a side view of one embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA. High frequency circuit support 5'
has a plurality of cooling fins on its back side throughout the tube axis direction, and the case board 4 is secured by a stopper 8.
is screwed to. The case board 4 has a square hole 9 (indicated by diagonal lines) that serves as a passage for cooling air in the part of the high-frequency circuit support 5' directly below the input part of the cooling fin.
A duct is formed by the cooling fins and the case substrate in the part closer to the output part. Cooling air is arrow 1
As shown at 0, the air is sucked in through the square hole 9 and flows to the collector side through between the cooling fins. Heat due to high frequency losses generated on the output side of the helix is therefore conducted from the vacuum envelope to the PPM and then to the high frequency circuit support 5', where it is dissipated by air passing between the cooling fins. Therefore, the cooling effect of the high frequency circuit can be greatly increased compared to the conventional example.

[Effect of idea]

As explained above, the present invention can greatly increase the cooling effect of the high frequency circuit by providing cooling fins on the back side of the high frequency circuit support and cooling the high frequency circuit, so the temperature of the high frequency circuit and PPM can be kept low. As a result, it is possible to suppress mechanical deformation due to thermal expansion of the high frequency circuit section, decrease in magnetic field due to thermal demagnetization of the PPM, and increase in high frequency loss of the helix. Therefore, it is possible to provide a high-output traveling wave tube without deteriorating beam transmission characteristics. Furthermore, since the high frequency circuit is supported almost entirely along the tube axis by the high frequency circuit support, it goes without saying that its mechanical strength is extremely high, just like in the conventional example.

[Brief explanation of the drawing]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a side view of the conventional example, and Fig. 4 is the high-frequency circuit support of Fig. 3. It is a perspective view showing a mechanism. 1...electron gun section, 2...high frequency circuit section, and
PPM section, 3... Collector section, 4... Case board,
5, 5'...high frequency circuit support body, 6...pressing plate,
7...screw, 8...stopper, 9...square hole, 10
...flow of cooling air.

Claims (1)

[Scope of utility model registration request] In a traveling wave tube in which a high frequency circuit section equipped with a periodic permanent magnet is supported and fixed by a high frequency circuit support body and a holding plate, a plurality of cooling fins are provided on the back side of the support body along the tube axis direction, and a case is further provided. A traveling wave tube characterized in that a hole is provided in the substrate to serve as a passage for cooling air, and a duct for cooling air is formed by the case substrate closer to the collector than the hole and the cooling fin.