Cold cathode structure for magnetron and millimeter wave magnetron

Abstract

The invention discloses a cold cathode structure for a magnetron, comprising a bottom metal rod, an upper shielding cap and a lower shielding cap sheathed on one end of the bottom metal rod, and a cold cathode arranged between the upper shielding cap and the lower shielding cap The emitter, the cold cathode emitter includes alternately arranged primary emitters and secondary emitters, and the primary emitters are located at both ends of the cold cathode emitter. The invention also discloses a millimeter-wave magnetron with a cold cathode structure, wherein the thickness of the cold cathode emitter is 0.62-6.5mm. The invention realizes the reliable interaction between the primary electron and the secondary multiplication phenomenon by alternately setting the primary emitter and the secondary emitter, and ensures the reliable startup of the magnetron; the magnetron manufactured by the cold cathode structure of the present invention No need for filament heating, instant start-up, no obvious start-up lag time, and electrical parameter characteristics after start-up are consistent with those of hot cathode magnetrons.

Description

Technical field [0001] The invention relates to the technical field of microwave vacuum electronics. More specifically, it relates to a cold cathode structure for a magnetron and a millimeter wave magnetron. Background technique [0002] Magnetrons are the most widely used vacuum microwave tubes in military and civil fields. They have the advantages of simple structure, high pulse power, long life, high cost, and small size. They can be used in missiles, communications, beacons, warning radars, etc. In the military field, it can be widely used in civilian fields such as medical treatment, communication, meteorology, chemical industry, industrial heating, and automobile ignition. [0003] However, in the prior art, a hot cathode is generally used as the electron source of a magnetron. Magnetrons working with this cathode have the following technical problems: First, the cathode must be preheated with a thermon before operation, and the preheating time At least 1 minute, sometimes ...

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Problems solved by technology

[0003] However, in the prior art, a hot cathode is generally used as the electron source of the magnetron, and the magnetron using this cathode has the following technical problems: first, the cathode must be preheated by a heater before work, and the preheating time At least 1 minute, sometimes even as high as 5 minutes; second, in order to preheat the hot cathode of the magnetron, the power supply of the magnetron must be added to the filament power supply part, and generally the filament transformer is floating on the negative high voltage of the cathode, the complexity of the power supply Third, the operating temperature of the hot cathode is generally above 850 ° C, the high operating temperature, the serious evaporation of the cathode emission material, and the low life

[0004] In the prior art, the carbon nanotube cold cathode adopts a planar emission structure, which is generally used for primary emission occasions. It has poor bombardment resistance and cannot provide secondary electron emission, so it is not suitable for application in magnetrons.

However, the cathode structure that provides secondary emission in the prior art is a composite cold cathode, and its secondary emitter is a tungsten sponge or a nickel sponge. It is also easy to precipitate gas under the bombardment of an electron. Generally, it is necessary to use a hot wire to degas the cathode at high temperature, which increases the complexity of the structure.

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