Method for restraining secondary emission of surface nano-structure of microwave component

Abstract

A method for restraining the secondary emission of a surface nano-structure of a microwave component comprises the following steps that: a metal nano-structure is formed on a good conductor layer of a microwave component basal body; different test conditions are selected, and comprise the porosity, depth-to-width ratio and shape of the nano-structure; a Monte-Carlo simulation is utilized to simulate the collision and absorption processes of an electron which enters the nano-structure and the collision, absorption and escape processes of a secondary electron which is produced by the electron, and the secondary emission yield of a single nano-structure is theoretically obtained; and according to the principle of secondary emission yield, various surface treatment technologies are utilized to adjust the shape, depth-to-width ratio and porosity of the surface nano-structure of the microwave component, so the secondary emission yield is the minmum. The method can greatly improve the micro discharge threshold of the microwave component which undergoes the electrochemical silvering surface treatment; and the secondary electron trap structure with high depth-to-width ratio is easier to realize, the influence on surface roughness can be neglected to a certain extent, and negative effects which are caused by restraining the secondary emission yield (SEY) of the current large roughness structure surface are solved.

Description

Technical field: [0001] The patent of the present invention relates to the field of surface treatment of microwave components, in particular to a method for suppressing secondary electron emission by nanostructures on the surface of microwave components. Background technique: [0002] At present, most of the microwave passive components in the satellite payload system are based on aluminum alloy. In order to reduce the loss of the device, the most commonly used method is the surface electrochemical silver plating. In actual use, these silver-plated parts are prone to multiplier discharge effect under the condition of high-power electromagnetic wave transmission, which is called micro-discharge phenomenon. Micro-discharge breakdown of microwave components is one of the main factors that determine the reliability and life of satellites. One of the necessary conditions for the occurrence of micro-discharge is that the average secondary electron emission coefficient on the cavi...

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Problems solved by technology

The first way is to prepare new low-SEY coating materials on the surface of components, such as Alodine, TiN, AgO, etc. The significant advantages of these coatings are small surface SEY and good environmental stability, but this method has disadvantages, that is, the coating itself is conductive Poor performance leads to large surface impedance under high frequency conditions, which is difficult to popularize in engineering

The second way is to form a large roughness on the surface of the silver coating, and use the principle that the secondary electrons are reflected and absorbed in the structure gap with large roughness to reduce the average SEY of the surface, thereby increasing the micro-discharge threshold of microwave components. The advantages of this method are: It avoids the high loss problem caused by the non-good conductor coating in the above approach and can reduce SEY at the same time. Therefore, this research method has received great attention and subject support in the field of European and American aerospace satellite payload research, but this type of large roughness The size of the microstructure on the surface is often larger than the skin depth under high-frequency conditions, and the increase in the insertion loss of microwave components is still not negligible. The surface treatment process of forming a micron-scale large aspect ratio rough structure on the coating encounters a bottleneck in the preparation technology, and there are potential hidden dangers in the crack defects and pollution caused by these processes

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