24499172

RFI and EMI - Shielding and Absorbing Materials

Radio-Frequency Interference (RFI) and Electromagnetic Interference (EMI) are issues that are increasingly become more familiar in various industries. The two main ways of addressing such issues are shielding and absorbing. The 24499172 application field and working principles of these techniques are very complex and involve a variety of materials. This article looks at the materials employed for RFI and EMI shielding and absorbing materials, their intended application fields, and their working principles.

Ferrites and absorbing materials

Ferrite materials are widely used both for EMI and RFI shielding and absorbing. They are composed of nitrides of iron, nickel or cobalt combined with other elements such as lead or barium. Ferrite is generally used to reduce the size, weight and cost of components while providing an effective level of absorption. Ferrite is an effective absorbing material as it is able to accommodate the high-frequency current moving through the core. It can also provide effective signal absorption across different applications as it has a high Curie temperature. This makes it suitable for use with different applications such as radio broadcasting, and communication.

Aside from ferrite, there are a number of materials that can be used as absorbers. The most prominent among these include copper, aluminum, steel, synthetic rubbers, foil and absorber foam. They can be used in combination with other materials such as plastics, wood, or other materials depending on the intended application. Copper and aluminum are considered to be the most effective absorbers because of their electrical conductivity. Their effect is further increased when used with appropriate surface treatment, and when secured using appropriate fastening technology.

Shielding Materials

Shielding materials are used to prevent the transmission of electromagnetic radiation. Commonly used materials for EMI shielding are tin-plated steel, aluminum, silver, carbon/graphite, copper alloys and nickel alloys. Due to the many different shapes and configurations available for shielding materials, they are able to provide a wide variety of shielding applications. Tin-plated steel is widely used because of its excellent shielding properties, and its flexibility when it comes to fabrication.

In addition to these materials, shielding materials can also include conductive metals and plastics, and non-conductive materials such as carbon-filled rubber and ceramic foam. Using a combination of two or more of these materials can help to increase the effectiveness of the shielding. For example, by including conductive metals such as copper and aluminum, and non-conductive materials such as plastics, the shielding effect can be enhanced.

When it comes to selecting the right shielding material, the two main considerations are the degree of shielding required and the cost. Different shielding materials can offer different levels of shielding effects. To determine the right degree of shielding, it is important to know the absorption and attenuation characteristics of the material. Generally speaking, materials such as aluminum, copper and nickel alloys offer higher levels of attenuation and absorption than those of tin-plated steel and carbon filled rubber.

Conclusion

The 24499172 application field and working principle of RFI and EMI shielding and absorbing materials provide effective solutions to the problem of electromagnetic interference. By selecting the right materials for the intended application field, it is possible to provide efficient and cost effective solutions that can help to mitigate the impact of EMI in a wide variety of applications across different industries.