JPH0538521Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a microwave tube using a helix in a slow wave circuit, and involves inserting the helix into an envelope,
Concerning improvements in helix retention.

[Conventional technology]

The helix-shaped microwave tube has an electron gun that emits an electron beam, a collector that captures the electron beam,
A slow wave circuit that amplifies the signal wave through continuous interaction with the electron beam, an input coupling section that feeds the signal wave to the slow wave circuit without loss, an output coupling section that transmits the signal wave to the load without loss, and an electron beam. It consists of a focusing device that considers the magnetic field for focusing. Although helix-type microwave tubes have the disadvantage of being relatively sensitive to heat, they have a simple slow-wave circuit structure and can use a periodic permanent magnet (PPM) to focus the electron beam, allowing for smaller size and lighter weight. It is characterized by very good frequency characteristics.

[Problem that the invention attempts to solve]

In conventional microwave band helix type microwave tubes, the outer diameter of the helix and the inner diameter of the envelope are relatively large, and there are no major dimensional restrictions when inserting the helix and support rod into the helix envelope. .

However, in a helical microwave tube in the quasi-millimeter wave band, the dimensions of the helix, helix support rod, and helix envelope are each smaller.
Strict dimensional accuracy is required when inserting the helix and the helix support rod into the helix envelope. In other words, when inserting a helix in the microwave band, it is possible to insert the helix even with a dimensional accuracy of about 0.03 to 0.05 mm, but when inserting a helix into a helix-shaped microwave tube in the quasi-millimeter wave band, the overall dimensions are smaller. Therefore, only an error of about 0.01 mm is allowed when inserting the helix.

However, in the conventional helix, the final outer diameter of the helix varies by about 0.02 to 0.03 mm due to degreasing and heat treatment after the helix is wound. Therefore, it was sometimes impossible to insert the helix into the helix envelope. This was caused by variations in the extensibility of the helix wire itself, variations in the tension during winding of the helix, variations during heat treatment, etc.

[Means for solving problems]

In order to eliminate these drawbacks, the present invention provides a helix-shaped microwave tube in which the helix itself is etched by chemical treatment.

〔Example〕

FIG. 1 shows a cross-sectional view of a helical microwave tube.

With conventional helices, that is, those that have only been degreased and heat treated, the dimensional accuracy of the outer diameter of the helix is not sufficient, and the insertion condition of the helix has large variations in whether it is loose or tight, and in the worst case, the outside of the helix may It also becomes impossible to insert it into a container. Furthermore, when looking at the characteristics of a microwave tube, there are large variations in the contact pressure between the helix, the helix support rod, and the envelope, which manifests itself in variations in the helix synchronization voltage. Furthermore, if the contact pressure is small, there is a possibility that an unexpected situation such as sputtering of the helix may occur due to an increase in the temperature of the helix itself.

In the helix type microwave tube according to the present invention,
After winding the helix, it is degreased and heat treated, and further chemically etched to improve the dimensional accuracy of the helix outer diameter. Therefore, the variation in the outer diameter of the helix can be kept to about 0.01mm.

[Effect of idea]

As explained above, as in the present invention, the dimensional accuracy of the outer diameter of the helix can be maintained through chemical treatment (etching) of the helix itself, making it possible to easily insert the helix into the helix envelope and at almost the same pressure. This becomes possible. Therefore, variations in the helix synchronization voltage are reduced, and the characteristics of the microwave tube are made more uniform.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a slow wave circuit section of a helical microwave tube. 1... Helix, 2... Helix support rod,
3...Helix envelope.

Claims (1)

[Scope of utility model registration request] In a microwave tube equipped with a helical slow-wave circuit that amplifies the signal wave through continuous interaction between the signal wave and the electron beam, the helix is chemically treated to make the outer diameter of the helix uniform and highly accurate. A microwave tube characterized by: