JPS6334576B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling structure for a high frequency circuit of a periodic permanent magnet (PPM) focused helix traveling wave tube.

A traveling wave tube generally includes an electron gun section that generates an electron beam, a high frequency circuit section that interacts with the electron beam and amplifies the microwaves, a collector section that captures the electron beam, and an input section that inputs and outputs the microwaves. It consists of an output coupling section, a beam focusing device that focuses the electron beam, a tube support mechanism, etc.

As a recent general trend, there is a demand for higher output from high-power microwave tubes, and periodic permanent magnets (PPM)
Helical traveling wave tubes that are used as electron beam focusing devices are also expected to have higher output than conventional ones. However, since the helical traveling wave tube has a relatively heat-resistant structure, high output cannot be achieved without special measures.

FIG. 1 shows an example of the structure of a conventional helical traveling wave tube. To briefly explain the figure, 1 is an electron gun section, 2 is a high frequency circuit section and
The PPM part, 3 indicates the collector part, and the case board 8 is supported by support plates 4, 5, 5', 6, 7, 7', respectively.
is fixed. Further, 9 indicates a coaxial plug for high frequency input, and 10 indicates a waveguide for high frequency output.
A case cover 11 having a U-shaped cross section is attached to the case substrate 8, and side plates 12 and 13 having a large hole in the center are attached to both ends of the case cover 11 to form a passage for cooling air of the traveling wave tube. Cooling air enters from arrow a and passes through the electron gun section 1, high frequency circuit section, and
The PPM section 2 and the collector section 3 are cooled down in sequence and exit in the direction of arrow b.

A traveling wave tube is a device that amplifies microwaves, and as the microwaves propagate on the high-frequency circuit from the input end to the output end of the high-frequency circuit, the power value of the microwave increases. However, since high-frequency circuits have a loss with respect to microwaves, high-frequency loss (loss due to microwaves) occurs as the microwaves pass through the circuit. Since the loss coefficient per unit length of the high frequency circuit is considered to be approximately constant, the absolute value of the high frequency loss increases as the absolute value of the microwave on the high frequency circuit increases. Therefore, when increasing the output of such a traveling wave tube, there is a
Cooling fins 14 are added to effectively radiate heat generated by high frequency loss.

However, it has been recognized that although such a structure is effective up to a certain power range, there is a limit to its effectiveness when it is desired to further increase the power level.

An object of the present invention is to provide a helical traveling wave tube having a new cooling structure that improves the drawbacks of the conventional structure and can operate stably even at relatively high power levels.

The present invention provides a helical traveling wave tube that uses a periodic permanent magnet as a beam focusing device. It is characterized in that it is equipped with a member that narrows the cooling air toward the cooling fins in order to particularly increase the flow velocity of the cooling air near the cooling fins.

Hereinafter, the structure of the present invention will be explained with reference to the drawings.

FIG. 2 shows an embodiment of a cooling structure for a helical traveling wave tube according to the present invention. In the present invention, in the vicinity of the cooling fins 14 of the high frequency circuit, there is provided a member that narrows the flow of air and narrows the cooling air toward the cooling fins 14, that is, an air path partition plate 1.
5, 15' are newly provided. In this way, the cooling air passing through the cooling fins 14 is squeezed and the flow velocity of the cooling air increases, so that the cooling effect is greatly improved. In addition, the partition plate 15,1
Since the tube 5' is installed only in a relatively short section in the tube axis direction, the overall static pressure does not increase much, and it can be put to practical use. In addition, these partition plates 15, 15' are
No matter how the shape is changed, if the purpose is to increase the wind speed near the cooling fin, it should be included in the present application. Furthermore, the partition plates 15 and 15' may be attached on the case substrate 8 or inside the case cover 11.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of the structure of a conventional helical traveling wave tube, and FIG. 2 is a side view showing an embodiment of the helical traveling wave tube according to the present invention. 1... Electron gun section, 2... High frequency circuit section, and
PPM section, 3... Collector section, 4, 5, 5', 6,
7, 7'...Support plate, 8...Case board, 9...
High frequency input plug, 10... Output waveguide, 11...
Case cover, 12, 13...Side plate, 15, 1
5'...Air passage partition plate.

Claims (1)

[Claims] 1. In a helical traveling wave tube housed in a wind tunnel-shaped case, a cooling fin is attached from outside the magnet to a position adjacent to the output section of the high frequency circuit section, and a cooling fin is attached to the magnet from the outside and passes through the cooling fin through the inside of the case. A helical traveling wave tube characterized in that a member for squeezing cooling air toward the cooling fins is disposed on an inner surface of the case facing the cooling fins.