How to ensure the isolation degree of the shielding box?
To ensure the isolation degree of the shielding box, measures can be taken in aspects such as box design, material selection, manufacturing process, as well as testing and maintenance. The specific methods are as follows:
Structural Optimization: Adopt a closed structure like a hexahedron to minimize unnecessary openings and gaps. If openings are necessary, such as ventilation openings and test interfaces, their sizes should be minimized, and special designs like waveguide windows and honeycomb panels should be used. The waveguide principle is utilized to restrict the passage of electromagnetic waves.
Rational Layout: The internal equipment and circuits should be arranged rationally to avoid creating paths for electromagnetic wave propagation. For example, power cords and signal lines should be laid separately to reduce electromagnetic coupling. There should be an appropriate distance between the testing equipment and the device under test to avoid mutual interference.
High - conductivity Materials: Give priority to metal materials with high conductivity, such as copper and aluminum. These materials can effectively reflect and absorb electromagnetic waves. Copper has excellent electrical conductivity and is very effective for electromagnetic shielding. Aluminum is lightweight and has a relatively low cost, so it is also often used in the manufacture of shielding boxes.
Shielding Coatings: Apply coatings with shielding properties, such as conductive paint, on the surface of the box. Conductive paint can form a conductive film on the surface of the box, enhancing the shielding ability against electromagnetic waves. It can be used to make up for minor defects on the surface of metal materials or enhance the overall shielding effect.
Absorbing Materials: Paste absorbing materials such as absorbing sponges and absorbing sheets inside the shielding box. Absorbing materials can absorb electromagnetic waves and convert them into other forms of energy such as heat, reducing the reflection and scattering of electromagnetic waves inside the box and improving the isolation degree.
Welding Process: High - quality welding processes should be used at the joints of the box to ensure that the welds are continuous, uniform, and free of defects such as cracks and pores, thus ensuring the tightness of the box. For example, welding methods such as argon arc welding can effectively improve the welding quality and reduce electromagnetic wave leakage.
Shielding Door and Sealing: The shielding door is a key part of the shielding box. Good sealing measures should be taken between the door and the door frame, such as installing conductive rubber strips, metal wire meshes and other sealing materials to ensure that the door can fit tightly with the door frame when closed, reducing gap leakage.
Cable and Interface Treatment: All cables entering the shielding box should use shielded cables and be properly grounded. Filter connectors should be used at the cable interfaces to filter out high - frequency interference signals on the cables and prevent electromagnetic waves from entering or leaving the shielding box through the cables.
Regular Detection: Use professional electromagnetic shielding testing equipment such as network analyzers to regularly detect the isolation degree of the shielding box. By measuring the transmission loss of the shielding box at different frequency points, problems such as a decrease in isolation degree can be detected in a timely manner.
Timely Repair: If isolation - degree problems are found during the detection process, the shielding box should be repaired in a timely manner. For example, repair the discovered gaps and holes, and replace the damaged shielding materials.
Environmental Management: Keep the environment around the shielding box clean and tidy. Avoid placing large metal objects or strong electromagnetic interference sources near it to prevent these factors from affecting the isolation degree of the shielding box. At the same time, control environmental conditions such as temperature and humidity to prevent the performance degradation of shielding materials due to environmental factors.
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