Anti-Multipactor Coating With Roughened Silver for Low SEY
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Solution Overview
Problem
High power devices in vacuum environments face multipactor discharges due to secondary electron emission, limiting power transmission and requiring anti-multipactor coatings with low secondary electron emission yield (SEY) and resistance to air exposure, while existing methods are costly, inefficient, or result in increased insertion loss.
Innovation Solution
A low SEY anti-multipactor coating deposited onto a substrate using a process involving high conductive metal layers with controlled surface roughness achieved through chemical methods, including deposition, acid etching, activation, and electroless plating, maintaining low SEY and insertion loss even after air exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silver coating is used for high electrical conductivity, then electrical conductivity is improved, but secondary electron emission yield increases above 2 after air exposure
Solution Approach 1:
The patent applies composite materials by combining silver coating with a roughened surface structure. The silver layer provides high electrical conductivity while the roughened surface (with grooves, pits, or protrusions) reduces secondary electron emission yield to below 1.1, creating a composite surface that achieves both low energy loss and low harmful electron emission.
2Object-generated harmful factors
If surface roughness is increased to reduce secondary electron emission, then secondary electron emission yield is reduced, but insertion loss increases due to high surface electrical resistance
Solution Approach 1:
The patent applies local quality by creating localized roughened regions (grooves, pits, or protrusions) on the silver surface rather than uniform roughening. This localized approach reduces secondary electron emission at specific high-risk areas while maintaining sufficient smooth areas to preserve low surface electrical resistance and minimize insertion loss.
3Ease of operation
If air exposure is allowed for practical applications, then ease of operation is improved, but secondary electron emission yield increases from 0.5 to 2 making coatings unusable
Solution Approach 1:
The patent applies preliminary action by pre-roughening the silver surface before air exposure. The roughened surface structure is created in advance through chemical etching or mechanical means, which establishes a permanent geometric configuration that maintains low secondary electron emission yield even after prolonged air exposure, allowing practical operational use.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coating effectively reduces secondary electron emission and insertion loss, allowing high power devices to operate at high frequencies without multipactor discharges, with SEY between 0.4 and 0.9 and insertion loss of 0.1-0.14 dB, and maintains performance after long air exposure.
Implementation Method 1
A first conductive layer is chemically deposited onto the substrate
Implementation Method 2
The coating is then etched with an acid solution to increase the surface roughness
Implementation Method 3
A second conductive layer is then electroless plated onto the etched surface
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
The invention relates to a coating deposited on a substrate that can be exposed to the air and to the method for the production thereof by means of simple chemical methods. The invention also relates to the use thereof for the production of high-power devices operating at high frequencies.