JPH07321501A - Structure of air-tight window for microwave transmission - Google Patents

Abstract

PURPOSE:To provide the structure of an air-tight window for microwave transmission which is easily assembled and in which a dielectric air-tight window and a circular waveguide are entirely and efficiently cooled. CONSTITUTION:The window structure is made up of a rectangular waveguide section 1, a circular waveguide section 12 whose axial length is equal to or more than a guide wavelength and a rectangular waveguide section 13 in this order, a dielectric airtight window 23 is provided to a middle part of the circular waveguide section 12, a coolant path 20 is formed in a part corresponding to the outer circumferential part of the dielectric air-tight window 23, and the circular waveguide section 12 is divided into three parts being a part having a dielectric airtight window 30 and parts with which each of the rectangular waveguide sections 11, 13 is integrally coupled at both sides and whose outer circumferential parts are formed with coolant paths 21, 22, and the three parts are removably and air-tightly connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airtight window structure for microwave transmission suitable for use in a microwave tube device such as a klystron.

[0002]

2. Description of the Related Art Generally, an airtight window structure for microwave transmission is
It is used in various devices including an output part of a high power klystron and other high power microwave transmission circuits. For example, a so-called pill box type is used as a waveguide of the output part of the klystron. That is, when the length of the circular waveguide portion is L and the in-tube wavelength is λg, a conventional microwave-tight window structure for microwave transmission, in which L is about ¼ of λg, is constructed as shown in FIG. Has been done. The rectangular waveguide part 1, the circular waveguide part 2 and the rectangular waveguide part 3 are connected in this order, and the dielectric airtight window 4 is provided in the middle part of the circular waveguide part 2 and A cooling medium passage 5 is formed in a portion corresponding to the outer circumference of the airtight window 4. The flanges 6 and 7 near both ends of the circular waveguide portion 2 are hermetically connected to the flanges 8 and 9 by screws 10.
This pill box type airtight window structure for microwave transmission is
As described above, the length L of the circular waveguide section 2 is selected to be about ¼ of the guide wavelength λg. On the other hand, L is a quarter of the guide wavelength λg
The so-called long pill box type, which is set to a length more than twice as long as that of US Pat.
9102 and others. Such a long pill box type has a relatively low electric field strength at the position of the dielectric hermetic window, and therefore can withstand transmission of a larger amount of power.

[0003]

In such a so-called long pillbox type airtight window structure for microwave transmission, since the length L of the circular waveguide portion is long, the following problems occur. (1) It is difficult to vapor-deposit a multipactor discharge preventing coating made of, for example, TiN to a uniform thickness on the surface of the dielectric hermetic window, and it is difficult to assemble.

(2) It is difficult to cool the entire tube wall of the circular waveguide section. That is, a dielectric airtight window is airtightly joined to a locally thin tube wall, but a large water pressure cannot be applied to this thin wall, so the entire circular waveguide section must be efficiently water cooled. Becomes difficult.

Incidentally, as another conventional example, Japanese Unexamined Patent Publication No. 60-
Although there are those described in Japanese Patent No. 187101 and Japanese Utility Model Laid-Open No. 61-62337, there are disadvantages that it is difficult to uniformly deposit a multipactor discharge preventing coating, or the structure becomes extremely complicated.

The present invention eliminates the above-mentioned inconveniences, is easy to assemble, and is capable of efficiently cooling the dielectric airtight window and the circular waveguide part as a whole. The purpose is to provide a structure.

[0007]

The present invention comprises a rectangular waveguide section, a circular waveguide section having an axial length equal to or longer than the in-tube wavelength, and a rectangular waveguide section in this order. In the hermetic window structure for microwave transmission, a dielectric airtight window is provided in an intermediate portion of the circular waveguide portion, and a cooling medium path is formed in a portion corresponding to the outer periphery of the dielectric airtight window. The part is divided into three parts, a part having a dielectric airtight window and a part in which the circular waveguide parts on both sides thereof are integrally coupled and a cooling medium path is formed on the outer periphery, and these three parts can be detached. This is an airtight window structure for microwave transmission that is airtightly connected.

[0008]

According to the present invention, the assembly is easy, and the dielectric airtight window and the circular waveguide can be efficiently cooled as a whole. Further, it is also possible to disassemble each part as required and reuse it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The microwave transmission airtight window structure according to the present invention is constructed as shown in FIGS. 1 to 3, FIG. 1 shows the whole, FIG. 2 shows an enlarged main part of FIG. 1, and FIG. 2 is an exploded view of FIG. 2, and the same portions are denoted by the same reference numerals. That is, the rectangular waveguide portion 11, the circular waveguide portion 12, and the rectangular waveguide portion 13 on the vacuum region side are configured in this order, and the circular waveguide portion 12 has an axial direction equal to or greater than the guide wavelength λg. It is a so-called long pill box type having a length L, and has a relationship of L ≧ λg. Further, as is clear from the exploded view of FIG. 3, the circular waveguide portion 12 has a portion A having a dielectric airtight window (described later) in advance and the rectangular waveguide portions 11 and 13 on both sides thereof. Is divided into three parts, a B part and a C part, which are integrally connected, and these three parts are detachably airtightly connected. Each part is composed of an inner cylinder 14, 15, 16 made of copper and an outer cylinder 17, 18, 19 made of stainless steel. As described above, since the inner cylinders 14, 15, 16 are made of copper, high frequency loss is small, and the outer cylinders 17, 18, 19 are made of stainless steel, so that mechanical strength can be secured. These inner cylinders 14, 15, 16 and outer cylinders 17, 18,
19 and the independent cooling medium paths 20 and 2
It is 1, 22. That is, the circular waveguide 12 is
The cooling medium paths 20, 21, 22 are formed on the respective outer peripheries. A dielectric airtight window 2 made of ceramics is provided in the middle of the circular waveguide 12, that is, in the center of the portion A.
3 is provided and airtightly joined to the thin portion of the inner cylinder 14 by brazing. On one side or both sides of the dielectric airtight window 23, a multipactor preventing coating 24 made of, for example, TiN is attached by vapor deposition. A wire 25 made of molybdenum is wound around the cooling medium passage 20 side of the thin portion. However, the wire 25 is not shown in FIG.

Further, the airtight joining flange 2 made of thin metal is provided at each of the mutual connecting portions of the A, B, and C portions.
6, 27, 28, and 29 are provided in a protruding manner, and welded at D and E, which are hermetically joined by a heliarc. In addition, each of the mutual coupling portions has a thick fastening flange 30, 31, 32,
33 is projected and fixed, and mechanically tightened and fixed by a plurality of fastening bolts 34 and nuts 35 through a conductive gasket (not shown). In addition, each cooling medium path 20, 21, 2
A water pipe (not shown) is connected to each of 2 so that cooling water can be independently introduced and drained. Further, reference numerals 36 and 37 in FIG. 1 are both waveguide flanges.

In assembling, as shown in FIG. 3, parts A, B, and C are preliminarily assembled individually. A
Since the portion has a relatively short size, when depositing the multipactor discharge preventing coating 24 on the entire surface of the dielectric hermetic window 14, only the portion A enters the vapor deposition furnace, so that the coating can be easily formed. Therefore, the multipactor discharge preventing coating 24 having a uniform film thickness can be formed.

Such a long pill box type airtight window structure for microwave transmission has a long size, but it is relatively easy to form and connect the multipactor discharge preventing coating 24 and is excellent in assembling. . Further, since the A, B, and C sections have independent cooling medium passages 20, 21, and 22, water can be passed to each section for optimal cooling, and efficient cooling can be performed. Further, it is possible to apply a relatively high water pressure, and it becomes easy to obtain a large flow rate. As a result, it is not necessary to select a material having a large heat transfer coefficient for the surface on which the high frequency is propagated, and the material selection range is expanded. Further, since the parts A, B, and C can be separated / divided, they can be reused. In particular, the portion A to which the dielectric airtight window 14 is brazed can be used by reassembling it as an output window component of a high power high frequency source such as a klystron after being combined and tested as a single output window structure. Is.

[0013]

As described above, according to the present invention,
The circular waveguide part is divided into three parts, a part having a dielectric airtight window and a part in which the circular waveguide parts on both sides thereof are integrally coupled and a cooling medium path is formed on the outer periphery. Is detachably airtightly connected, so assembly is easy and
In addition, the dielectric airtight window and the circular waveguide section can be efficiently cooled as a whole. Moreover, it is easy to form a film on the surface of the dielectric airtight window and a uniform film thickness can be formed.
Further, it is also possible to disassemble each part as required and reuse it.

[Brief description of drawings]

FIG. 1 is a sectional view showing an airtight window structure for microwave transmission according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of FIG.

FIG. 3 is a sectional view showing FIG. 2 in an exploded manner.

FIG. 4 is a cross-sectional view showing a conventional airtight window structure for microwave transmission.

[Explanation of symbols]

11, 13 ... Rectangular waveguide section, 12 ... Circular waveguide section, 1
4, 15, 16 ... Inner cylinder, 17, 18, 19 ... Outer cylinder, 20, 21, 22 ... Cooling medium passage, 23 ... Dielectric airtight window, 24 ... Multipactor discharge prevention coating.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Ito 1385-1 Shimoishigami, Otawara-shi, Tochigi Stock Company Toshiba Nasu Electronic Tube Factory

Claims (1)

[Claims] 1. A rectangular waveguide section, a circular waveguide section having an axial length equal to or longer than an in-tube wavelength, and a rectangular waveguide section are formed in this order, and the circular waveguide section has In a microwave transmitting airtight window structure in which a dielectric airtight window is provided in an intermediate portion and a cooling medium path is formed in a portion corresponding to the outer periphery of the dielectric airtight window, the circular waveguide portion is made of the dielectric material. A portion having an airtight window,
Each of the rectangular waveguide parts on both sides thereof is integrally connected and divided into three parts in which a cooling medium path is formed on the outer periphery, and these three parts are detachably airtightly connected. Airtight window structure for wave transmission.