JPH0582037A - Coaxial magnetron - Google Patents

Abstract

PURPOSE:To decrease gas generation, acquire a stable characteristic, and shorten the manufacturing processes. CONSTITUTION:A microwave attenuator 3 is made in block form and fixed by brazing to the inner wall of an anode 1 in the upper part of a coupling slot 2. The volume of a microwave absorber 3 is decreased, and gas generation can be suppressed. Brazing fast to the anode 1 of the microwave attenuator 3 permits conducting of the heat generated at the time of slot mode absorption effectively to the anode 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coaxial magnetron, and more particularly to a coaxial magnetron having a microwave attenuator for absorbing unwanted modes.

[0002]

2. Description of the Related Art The anode of a coaxial magnetron is shown in FIG.
As shown in (a) and (b), every other resonator 4 has a coupling slot 2 which is coupled to an external resonant cavity through the coupling slot 2.

In the conventional coaxial magnetron, the microwave attenuator 13 is formed in a ring shape from the ease of making the microwave attenuator and at the time of manufacturing the magnetron, and the microwave attenuator 13 is installed on the coupling slot 2 and caulked. It is fixed by etc. During operation of the magnetron, the slot mode electric field 6 shown in FIG. 4 is absorbed by the microwave attenuator 13 above the coupling slot 2 and disappears.

[0004]

Although the conventional microwave attenuator has a ring shape, only the upper portion of the coupling slot is effective as the attenuator. For this reason,
Only a part of the total volume is effective. As the microwave attenuator, usually, a porous alumina ceramics which is carbonized, or a SiC ceramics excellent in the characteristics of the microwave attenuator is used.
Unlike a metal, these microwave attenuators have a characteristic of releasing a large amount of gas in an exhausting step of bringing a magnetron into a vacuum state. When operated as a magnetron, heat is generated when the slot mode is absorbed to further generate gas.

If the generated gas becomes extremely large, the time spent in the exhaust process becomes long, and during the operation of the magnetron, gas molecules adhere to and collide with the cathode, thereby deteriorating the electron emission capability of the cathode and causing the magnetron. There was a problem that it reached the defect of itself.

An object of the present invention is to provide a coaxial magnetron in which a small amount of gas is emitted from the microwave attenuator, the exhaust process can be shortened, and stable characteristics can be obtained.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to a cylindrical cathode arranged in the center, an anode arranged outside the cathode coaxially with the cathode, and an even number arranged on the inner wall of the anode. Coaxial resonator having a resonator, a coupling slot formed in every other wall of the anode of the resonator, and a resonance cavity coupled to the outside through the coupling slot. A microwave attenuator for absorbing an unnecessary mode called a slot mode generated in the above is installed only in the coupling slot portion.

[0008]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of an anode according to a first embodiment of the present invention.

In the first embodiment, as shown in FIG. 1, a block-shaped microwave attenuator 3 for absorbing an unnecessary mode called a slot mode is coupled to a coupling slot 2.
In the example of being fixed to the inner wall of the anode 1 at the upper part by brazing, the slot mode is sufficiently absorbed even if the volume of the microwave attenuator 3 is reduced, and the gas generated from the microwave attenuator 3 can be reduced.

FIG. 2 is a partially cutaway perspective view of the anode according to the second embodiment of the present invention.

The second embodiment is an example in which a cylindrical microwave attenuator 3 is fixed to the inner wall of the anode 1 above the coupling slot 2 by brazing, as shown in FIG. Is the same as the embodiment described above.

Although the example in which the microwave attenuator is fixed by brazing has been described above, the microwave attenuator can be fixed by caulking.

[0014]

As described above, according to the present invention, the volume of the microwave attenuator can be reduced by forming the microwave attenuator for the slot mode absorption of the coaxial magnetron into a block shape or a column shape. It was Therefore, the gas generated from the microwave attenuator at the time of manufacturing the magnetron can be reduced, so that there is an effect that a magnetron having stable characteristics can be obtained without shortening the manufacturing process and deteriorating the performance of the cathode.

Further, since the heat conduction is improved by brazing the microwave attenuator as compared with the case where the microwave attenuator is fixed by caulking or the like, the heat generated by absorbing the slot mode during the magnetron operation can be efficiently conducted to the anode. further,
It has an effect that the generated gas can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an anode according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of an anode according to a second embodiment of the present invention.

3A and 3B are configuration diagrams of an example of an anode of a conventional coaxial magnetron, in which FIG. 3A is a partially cutaway perspective view and FIG. 3B is a sectional view thereof.

FIG. 4 is a principle diagram showing a slot mode electric field of a coupling slot.

[Explanation of symbols]

 1 Anode 2 Coupling Slot 3,13 Microwave Attenuator 4 Resonator 5 Resonant Cavity 6 Slot Mode Electric Field

Claims (2)

[Claims] 1. A cylindrical cathode arranged in the center, an anode arranged outside the cathode coaxially with the cathode, an even number of resonators arranged on the inner wall of the anode, and the resonator. In a coaxial magnetron having every other coupling slot formed in the wall of the anode and a resonant cavity coupled to the outside through the coupling slot, there is no need to call a slot mode generated in the coupling slot portion. A coaxial magnetron, wherein a microwave attenuator for absorbing a mode is installed only in the coupling slot portion. 2. The coaxial magnetron according to claim 1, wherein the microwave attenuator is fixed to the inner wall of the anode by brazing.