JPS5880244A - Linear beam type microwave tube - Google Patents

Abstract

PURPOSE:To reduce the outer dimension of a ceramic to the conventional level and to insure wind flow in a radiator panel, by providing a high frequency attenuating means on a high frequency path in the vacuum from a gap to be formed by an output side magnetic pole and the collector bottom face section to a ceramic. CONSTITUTION:In a path in the vacuum for passing the leakage electromagnetic wave, a high frequency attenuator is applied on the surface of said path where a high frequency attenuator such as the tantalum, titanium, etc. is arranged or the stainless steel is sprayed in a thin film on the surface of a collector side vacuum interior (a) of an output side magnetic pole, the inside (b) of a sealing pan 4a and the vacuum inner and outer faces of a collector body 5. Consequently the wind flow passing through a radiating panel 6 is insured with the conventional outer dimension of an insulative ceramic.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a straight beam microwave amplifier tube.

As is well known, a linear beam type microwave amplifier tube consists of an electron gun section that generates an electron beam, a high frequency circuit section that interacts with the electron beam, a collector section that captures the electron beam,
The main components are a beam focusing device that focuses the electron beam, and typical examples include a talistron and a traveling wave tube.

FIG. 1 shows the parts related to the present invention of a coupled cavity type traveling wave tube having an air-cooled collector as an example of a direct beam microwave tube. In Fig. 1, l is a high frequency circuit, 2 is an output magnetic pole, 3 is a ceramic for insulating and airtighting the collector from the high frequency circuit, 4m and 4b are sealing plates, 5 is a collector body, and 6 is a collector body. 6 shows a large number of heat sinks attached radially.

The electron beam 7 indicated by the dotted line is on the electron gun side (left side of the figure)
It then passes through the center of the high-frequency circuit and is caught on the inner wall of the collector. The high frequency power is amplified as it travels through the high frequency circuit 1, and the amplified power is extracted from the output circuit 8.

One of the problems with microwave tubes having such a structure is external feedback oscillation. The principle is that the high frequency energy of the electron beam is not only extracted from the output circuit 8, but also from the air rs9 between the collector 5 and the magnetic pole 2, and the power passes through the ceramic 3 and is radiated to the outside. A part of it is fed back to the input side, forming a loop and causing oscillation. As a conventional technique for solving this problem, a method has been adopted in which an annular high-frequency attenuator 10 is placed on the outside of the cellar rack 3 and molded with silicone rubber 11 in order to fix it while maintaining high pressure. As the high frequency attenuator 10, porous ceramic impregnated with carbon is used. .

Due to the action of the high-frequency attenuator 10, the power leaking from inside the ceramic 3 is attenuated, and the condition that causes the above-mentioned return loop to oscillate is prevented. However, as a drawback of such conventional technology, the high frequency attenuator 1
The outer diameter dimension of the silicone rubber portion 11 including 0 is increased, and therefore the flow 12 of air that should flow into the heat sink 6 is obstructed to some extent. If the cooling air volume decreases, the operating temperature of the collector main body 5 will rise, and it may become difficult to operate as a microwave tube. On the other hand, if the external dimensions of the lid main body 5 are made to be similar to the external dimensions of the silicone rubber part 11, the flow of air will be improved, but the weight of the collector main body will increase, and the support structure of the collector main body and the handling of the pipes will be affected. Another problem arises at this point.

The present invention takes into account the shortcomings of the prior art, and while incorporating the basic idea of the prior art, keeps the external dimensions of the ceramic that supports and insulates the collector to the same size as before, and increases the inside of the heat sink 6. The purpose is to ensure the amount of air passing through.

An example of the structure of a microwave tube employing the present invention is shown in FIG. 2. In FIG. 2, a high frequency attenuator is provided on the surface of a passage inside a vacuum through which leakage electromagnetic waves pass. ＾ Physically, this is tantalum and titanium on the surfaces of the collector side vacuum interior (part 1) of the output side magnetic pole, the inside of the sealing enclosure plate 4m (b part), and the vacuum inner and outer surfaces G of the collector body! (In the present invention, the position of the high-frequency attenuator is closer to the electron beam side, so there is no effect on leakage electromagnetic waves.) This method is more effective than the conventional technology. Also, since it does not change the external dimensions of the tube outside the vacuum, there is no problem such as a decrease in collector cooling air volume, which is one of the ways to downsize the microwave tube. This provides an effective method for

Note that FIGS. 1 and 2 are illustrative diagrams for explaining the present invention, and the frequency envelope is not limited to the coupled cavity type, but also includes helix type, ring and bar type, and tall type. Any array of cavities for stolons may be used. In addition, permanent magnet type and periodic permanent magnet type (PPM) are used as beam focusing devices.
Either an s-electromagnet or an electrostatic focusing type can be used. Furthermore, although an air-cooled collector is shown here as a collector,
It is clear that the present invention is also applicable to water-cooled collectors or evaporatively cooled collectors.

[Brief explanation of drawings]

FIG. 1 shows the structure of a conventional microwave tube, and FIG. 2 shows the structure of a microwave tube according to the present invention. 1...High frequency circuit, 8...Magnetic pole, 3.
... Ceramic, 4 hatake, 4b ... Sealing tray, container ... Core lid body, 6 ...
・Heat sink, 7...Electron beam, 8...
Output (9) path, 9... air gap, lO...
frequency attenuator, 11... silicone rubber, 12-
...Wind flow, a, b, c...High frequency attenuator.

Claims (1)

[Claims] The high frequency circuit section and the collector section are insulated and sealed via ceramic, and the gap formed by the output side magnetic pole and the collector bottom section forms a single high frequency action melt for the electron beam. A straight beam type microwave tube, characterized in that a high frequency attenuation means is provided on the high frequency passage in vacuum leading to the ceramic.