JPS6367801A - Airtight window for microwave and milliwave - Google Patents

Abstract

PURPOSE:To increase the electric power of an electromagnetic wave which can be transmitted by sandwiching a disk made of ceramic or sapphire between metallic cylinders as two waveguides from both sides, and placing a soldering material on their seam and soldering them. CONSTITUTION:The disk 1 made of ceramic or sapphire has a metallized layer 2 on its outer peripheral part. The disk 1 is sandwiched between the two metallic cylinders 4 from both sides and the soldering material 3 is placed on their seam to solder the both. A slight cut is made at the parts of the metallic cylinders 4 where the disk 1 is sandwiched to reduce the step between the internal wall of the metalized layer of the disk and the internal walls of the metallic cylinders 4 as much as possible. Thus they are soldered and then the presence of the soldering material 3 is limited to the contacting part between the ceramic-or sapphiremade disk 1 and the metallic cylinders 4 and the soldering material 3 neither bleeds out to the internal walls of the metallic cylinders 4 nor stains the surface of the disk. Consequently, the reflection of the electromagnetic wave and the generation of an unnecessary mode at the joined part and electric discharging on the surface of the disk 1 are precluded to increase the electric power of the electromagnetic wave which is transmitted through a window.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is for airtightness of vacuum or pressurized gas inside a microwave tube or millimeter wave tube or a high power microwave or millimeter wave waveguide system. This relates to airtight windows for microwaves and millimeter waves.

[Conventional technology]

As shown in Fig. 2, a conventional airtight window for microwaves and millimeter waves has a metallized layer 2 formed on the outer periphery of a ceramic or sapphire disk 1, and the disk 1 is connected to a metal cylinder serving as a waveguide. 4 is joined by low welding to the inside of the circle [metal on the left and right with 1 as the border.

The inside of the cylinder 4 is hermetically sealed. 3 is a material for raw joining. Further, on the outside of the raw joint portion, a passage is provided for flowing cooling water to remove heat generated in the ceramic or sapphire disk 1. Arrow 6 indicates the direction in which the cooling water flows. Further, a reinforcing wire 7 is wound around the outer periphery of the metal cylinder 4 corresponding to the row joining position. This wire 7 is used to prevent a gap from being formed in the raw joint part due to the difference in expansion coefficient between the ceramic or sapphire disk 1 and the metal cylinder 4 during raw jointing. It is rolled up. Further, the reason why the metal cylinder 4 in this part is made thin is to facilitate low joining.

(Problems to be Solved by the Invention) However, in the conventional airtight window for microwaves and millimeter waves, a ceramic or sapphire disk and a metal cylinder are low-bonded in the shape shown in Fig. 2. It is unavoidable that the brazing material protrudes from the inner wall of the metal cylinder.

Therefore, these protrusions may reflect electromagnetic waves, generate unwanted modes, and furthermore, make it easier for high-power microwaves or millimeter waves to discharge on the ceramic or sapphire surface, limiting the power of electromagnetic waves that can pass through the airtight window. There was a problem.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain an airtight window for microwaves and millimeter waves that can increase the power of electromagnetic waves that can be transmitted.

[Means for solving problems]

The airtight window for microwaves and millimeter waves according to the present invention is made by sandwiching a ceramic or sapphire disk between two metal cylinders serving as waveguides from both sides, placing a soldering material at the joint, and performing a soldering process. This is what I did.

[Operation] In this invention, the brazing material used for brazing the ceramic or sapphire disk to the metal cylinder does not flow out onto the inner wall of the metal cylinder and does not form any protrusions, so that Reflection of electromagnetic waves, generation of unnecessary modes, and discharge on the disk surface are prevented.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. In the figure, reference numeral 1 denotes a ceramic or sapphire disk, which is used to maintain airtightness of vacuum or pressurized gas, and has a metallized layer 2 on its outer periphery. 3 is a contact material, 4 is a metal cylinder that acts as a waveguide, 5 is a hollow space through which cooling water flows to remove the heat generated in the ceramic or sapphire disk 1, and 6 is a metal cylinder that acts as a waveguide. This is the direction in which the cooling water flows.

Disc 1 to 2 fl? They are sandwiched from both sides by the metal cylinders 4 of j, and the brazing material 3 is placed at the seam to perform brazing jointing. A slight notch is made in the part of the metal cylinder 4 where the disc 1 is sandwiched to make it easier to sandwich the disc 1.
The difference in level between the inner wall of the metallized layer 2 of the disk 1 and the inner wall of the metal cylinder 4 is made as small as possible.

When performing row welding using the tank structure as described above, the row welding material 3
Its presence is limited to the contact area between the ceramic or sapphire disk 1 and the metal cylinder 4, and the brazing material 3 does not seep into the inner wall of the metal cylinder 4 and does not stain the surface of the disk 10. Therefore, the reflection of electromagnetic waves at the joints, the generation of unnecessary modes, and the discharge on one surface of the disk, which are conventional, are prevented, and the power of the electromagnetic waves transmitted through the window can be increased.

〔Effect of the invention〕

As described above, according to the airtight window for microwaves and millimeter waves according to the present invention, since the ceramic or sapphire disc-shaped is sandwiched between circular waveguides and brazed together, the brazed welding material is applied to the circular waveguide. It does not contaminate the surface of the plate, does not cause any seepage protrusions on the inner wall of the waveguide, and prevents the reflection of electromagnetic waves due to the protrusions of the low-irradiation material at the joint, the generation of unnecessary modes, and the formation of protrusions on the disk surface. This solves the problem of electrical discharge, and it is possible to increase the power of electromagnetic waves that can pass through.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view showing a microwave/millimeter wave airtight window according to an embodiment of the present invention, and FIG. 2 is a sectional side view of a conventional microwave/millimeter wave airtight window. 1 is a ceramic or sapphire concave disk, 2 is a metallized layer, 3 is a soldering material, 4 is a metal cylinder, 5 is a cavity, 6 is a direction in which cooling water flows, and 7 is a ? 11i strong wire. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a microwave/millimeter wave airtight window for vacuum or pressurized gas sealing, which is formed by low-bonding a circular waveguide with a circular waveguide made of a circular ceramic or sapphire disk with a metallized layer formed on the outer periphery, the above disk A brazing material is placed at the joint between the circular waveguides, which sandwich the shaped ceramic or sapphire from both sides.
An airtight window for microwaves and millimeter waves, characterized by performing the above-mentioned low bonding.