JPH04280042A - Linear beam microwave tube - Google Patents

Abstract

PURPOSE:To satisfactorily focus an electron beam by using a coaxial microwave circuit for a microwave terminal section used in the high-frequency circuit section of a microwave tube. CONSTITUTION:Microwaves are propagated to a reflection-less terminal 10 through a coaxial line 7 arranged immediately after a coupling cavity 2 and absorbed. A magnet 6 is arranged like a conventional device on the outside of the coaxial line 7 for feeding microwaves to the reflection-less terminal 10, the outer diameter of the coaxial line 7 is made small, and a magnet 8 with a small notch is arranged. A high-frequency circuit section constituting a microwave tube is divided into multiple sections, a microwave terminal section 1 for terminating the sections has the reflection-less terminal 10 adapting the coaxial microwave circuit to the coaxial line 7, and an electron beam can satisfactorily be focused.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a traveling wave tube or a straight beam microwave tube such as a multi-cavity klystron used as a microwave amplifier, and more particularly to the structure of a high frequency circuit for amplifying microwaves. .

0002

2. Description of the Related Art As the output power and frequency of microwave tubes increases, many of the high frequency circuits of microwave tubes have a coupled cavity type structure. The high frequency circuit usually has a structure divided into two or three sections in order to maintain stable operation of the microwave tube. At the end of each section, there is a termination mechanism consisting of a sever cavity and a loss body, and it is necessary to reduce reflection in this termination mechanism in order to operate the microwave tube stably.

FIG. 3(a) is a longitudinal cross-sectional view of a microwave terminal portion 1 of a conventional microwave tube. Microwaves enter the Sever cavity 3 located immediately after the coupling cavity 2, and are absorbed by the loss body 4 at the end of the Sever cavity 3, making it possible to extremely reduce reflection of the microwaves. FIG. 3(b) is a cross-sectional view of the microwave termination section 1. FIG. On the outside of the loss body 4, there is a vacuum sealing part usually called a coupler 5, and a magnet 6 for converging the electron beam is arranged on the outside of the vacuum sealing part.

[0004] By terminating the microwave power in the loss body 4 and minimizing the amount of reflected microwaves,
Microwave tubes can operate stably without causing oscillation or the like.

[0005]

[Problems to be Solved by the Invention] The conventional microwave termination mechanism consists of a separator cavity 3, a coupler 5, and a loss body 4.
Since the outer diameter of the circuit is large because a microwave circuit consisting of Magnet 6 will be used. Therefore, the magnetic field in the part of the Sevar cavity 3 is
There was a problem in that the electron beam was weaker than the other part, and the electron beam could not be focused into the desired shape.

Furthermore, the conventional microwave termination mechanism is a microwave circuit resembling a so-called waveguide shape, and generally has a narrower passband than a coaxial line. For this reason, when used in a broadband microwave tube such as a traveling wave tube, there was a serious problem that good reflection characteristics could not be obtained and the tube would cause oscillation.

[0007]

[Means for Solving the Problems] The present invention provides that a high frequency circuit section constituting a microwave tube is divided into a plurality of sections, and a microwave termination section for terminating each section is
Instead of using a conventional waveguide type microwave circuit, it has a coaxial type microwave circuit and a non-reflection termination that is compatible with a coaxial line.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1(a) is a longitudinal cross-sectional view of the microwave termination section 1 of the first embodiment of the present invention, and FIG. 1(b) is a longitudinal cross-sectional view of the microwave termination section 1 of the first embodiment of the present invention.
FIG. Through the coaxial line 7 placed immediately after the coupling cavity 2, the microwave propagates to the non-reflection termination 10 and is absorbed. The structure in which the magnet 6 is arranged outside the coaxial line 7 for supplying microwaves to the non-reflection termination 10 is the same as the conventional one, but the outer diameter of the coaxial line 7 is thinner and the magnet 8 with a small notch is arranged. has been done.

FIG. 2 is a longitudinal sectional view of a microwave termination section 1 according to a second embodiment of the invention. Microwave termination section 1
The coaxial line 7 and non-reflection termination 10 are used in the first embodiment, but the coaxial line 7 is shorter than the first embodiment, and the outer diameter of the microwave termination is It is approximately the same as the outer diameter of the magnet 6. With this shape, the outer diameter of the microwave tube can be reduced, and a lightweight and compact microwave tube can be manufactured.

0010

Effects of the Invention As explained above, the present invention uses a coaxial type microwave circuit in the microwave terminal section used in the high frequency circuit section of the microwave tube, so that the magnet used in the terminal section can be The shape is approximately circular, and the magnetic field at the end portion does not differ from the magnetic field at other coupling cavities, resulting in the advantage that the electron beam can be well focused.

In addition, since a coaxial microwave circuit is used in the termination part, the microwave band can be widened, and the termination part has good reflection characteristics over a wide band, which reduces the oscillation of the tube. It has the effect of suppressing such problems.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a microwave termination section of a first embodiment of the present invention, in which (a) is a longitudinal cross-sectional view and (b) is a cross-sectional view.

FIG. 2 is a longitudinal cross-sectional view of a microwave termination according to a second embodiment of the invention;

FIG. 3 is a diagram showing a microwave termination section with a conventional structure;
) is a longitudinal cross-sectional view, and (b) is a cross-sectional view.

[Explanation of symbols]

1 Microwave termination part 2 Coupling cavity 3 Sever cavity 4 Loss body 5 Coupler 6 Magnet 7 Coaxial line 8 Small notch magnet 9 Circular magnet 10 Non-reflection termination

Claims (1)

[Claims] Claim 1: An electron gun section as an electron beam source, a high frequency circuit section that causes the electron beam to interact with microwaves, a collector section that captures the electron beam after interaction with the high frequency circuit, and a collector section that focuses the electron beam. In the linear beam microwave tube, the electron gun section, the high frequency circuit section, and the collector section are linearly arranged,
A straight beam microwave tube, wherein the high frequency circuit section is divided into a plurality of sections, and a microwave termination section for terminating each section has a coaxial type termination structure.