JPH08102264A - Slow wave circuit structure for traveling-wave tube - Google Patents

Abstract

PURPOSE: To provide the slow are circuit structure for traveling-wave tube, which can obtain the gradual microwave absorbing characteristic and which can stabilize the amplifying operation characteristic. CONSTITUTION: This slow wave circuit structure for traveling-wave tube is formed by connecting plural cavities 1 and providing concentration type attenuators 6a, 6b in the cavities of a part of these plural cavities. Microwave absorbing films 7a, 7b are formed on the inner wall of at least one cavity in fore and aft of the attenuators or in the slow wave circuit structural member so as to achieve the described purpose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slow wave circuit structure of a traveling wave tube, and more particularly to an improvement in the vicinity of an attenuator thereof.

[0002]

2. Description of the Related Art Generally, a cavity-coupled traveling-wave tube includes an electron gun section for emitting an electron beam, a slow-wave circuit structure for interacting the electron beam with an electromagnetic wave, and an electron beam after the interaction. -Collectors for capturing the frames are sequentially connected. The slow-wave circuit structure is conventionally constructed as shown in FIG. 2, in which a plurality of cavities 1 are coupled by a coupling hole 3 of a ferrule 2 and a port serving as a vacuum container is provided outside the cavities 1. Rupee
The spacer 4 and the spacer 5 are fitted together. Further, the centralized attenuators 6a and 6b mainly made of SiC are provided in some of the cavities 1a and 1b. The attenuators 6a and 6b are provided to prevent the return of electromagnetic waves from the output side and to prevent oscillation.

[0003]

The centralized attenuator 6a,
There is a slow wave circuit on both sides of 6b, which contributes to the amplification of microwaves. However, in the conventional structure as described above, the electric characteristics change rapidly at the centralized attenuator, so in the worst case,
Heat may be generated at the change point, and as a result, the characteristics of the traveling wave tube may become unstable.

The present invention has been made in view of the above points, and a smooth microwave absorption characteristic can be obtained before and after the lumped attenuator, and the amplification operation characteristic of the traveling wave tube can be stabilized. An object is to provide a slow wave circuit structure of a wave tube.

[0005]

According to the present invention, a plurality of cavities are coupled, and a centralized attenuator is provided in a part of the cavities, and the attenuator is further provided. Is a slow-wave circuit structure of a traveling-wave tube in which a microwave absorption coating is formed on at least one cavity inner wall or slow-wave circuit constituent member before and after.

[0006]

According to the present invention, a smooth microwave absorption characteristic is obtained before and after the lumped attenuator, and as a result, generation of a reflected wave in the middle of the slow wave circuit is suppressed, and the amplification operation characteristic of the traveling wave tube is stabilized. Can be turned into.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The slow-wave circuit structure of the traveling-wave tube of the cavity coupling type according to the present invention is constructed as shown in FIG. 1, and the same parts as those in the conventional example (FIG. 2) are designated by the same reference numerals. That is, the plurality of cavities 1 are coupled by arranging the plurality of ferrules 2 having the coupling holes 3 at predetermined intervals in the axial direction. Outside of these cavities 1, a magnetic pole piece 4 and a non-magnetic spacer 5 are alternately fitted.
These also serve as vacuum vessels. Furthermore, a plurality of cavities 1
A centralized attenuator 6 is provided in some of the cavities 1a and 1b.
a and 6b are provided. Then, microwave absorbing coatings such as nickel plating coatings 7a and 7b are formed on the inner walls of the cavities 1c and 1d before and after the centralized attenuators 6a and 6b, respectively.
Are formed. The formation of this microwave absorption coating is
It may be formed not only on the inner wall of the cavity 1 but also on another slow wave circuit constituent member. A magnet (not shown) is arranged between the respective pole pieces 4.

Thus, the nickel plating films 7a, 7b
As a result, the voltage standing wave ratio (VSW
R) can be reduced and reflection can be reduced.

In the above embodiment, the centralized attenuator 6 is used.
Although the nickel plating film is formed on each of the inner walls of the cavities on both sides of a and 6b, it may be formed on the plurality of inner walls of the cavities on both sides. In this case, the microwave absorption amount and its distribution may be changed by changing the material and the thickness.

The present invention can also be applied to a structure in which the ferrule also serves as a pole piece of the periodic magnetic field device.
Further, it can be applied not only to a cavity-coupled traveling wave tube but also to a helix type traveling wave tube.

[0011]

According to the present invention, since the microwave absorbing coating is formed on at least one cavity inner wall or the slow wave circuit constituent member before and after the centralized attenuator, the gentle microwave absorption is achieved. The characteristics are obtained. As a result, generation of a reflected wave in the middle of the slow wave circuit is suppressed, and the amplification operation characteristic of the traveling wave tube can be stabilized.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a slow wave circuit structure of a traveling wave tube according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a conventional slow wave circuit structure of a traveling wave tube.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cavity, 2 ... Feel, 3 ... Coupling hole, 4 ... Pol pace, 5 ... Spacer, 6a, 6b ... Attenuator, 7a, 7b
... Nickel plating film (microwave absorption film).

Claims (1)

[Claims] 1. A slow-wave circuit structure for a traveling-wave tube, comprising a plurality of cavities coupled to each other, and a centralized attenuator provided in a part of the cavities. 1. A slow-wave circuit structure for a traveling-wave tube, characterized in that a microwave absorption coating is formed on at least one cavity inner wall or a slow-wave circuit constituent member before and after the above.