EMI Shielding Materials

As electronic systems become increasingly complex and ubiquitous throughout modern life, the need for reliable electromagnetic interference (EMI) shielding solutions is more important than ever. Electromagnetic interference consists of unwanted radiated signals that can result in malfunctioning electronics, degradation of performance, signal interference, and even health and safety issues.

To maintain long-lasting optimal performance, electronic devices must be shielded from incoming and outgoing interference. At Hollingsworth & Vose, we offer effective, easy-to-incorporate EMI shielding materials developed to meet the needs of diverse applications.

EMI Shielding With Safe-N-Shielded 

Our Safe-N-Shielded fiber-based veils are wet-laid non-woven fabrics designed to minimize the effect of radiated electromagnetic energy by reflecting and/or absorbing it. Safe-N-Shielded veils consist of conductive, metalized fibers featuring highly efficient shielding capabilities. 

Safe-N-Shielded veils are manufactured with extreme uniformity and with basis weights as low as 6g/m2 for high porosity. They feature exceptional flexibility and easily conform to various structural components. Our EMI shielding solution is suitable for a range of applications, including: 

• Battery housings
• Composite panels and enclosures 
• Conductive tapes
• Electronics and avionics enclosures
• Motor and actuator housings
• Medical equipment
• Resistive heating

How EMI Shielding Works 

Electromagnetic waves consist of a magnetic field (H) and an electric field (E), which are perpendicular to one another. Waves are propagated at right angles to the plane that contains these two elements, and their relative magnitude depends on the waveform and its source. 

Wave impedance is the ratio of E to H. The intrinsic impedance of free space is 377 Ω. EMI shielding involves two regions: the near-field shielding region and the far-field shielding region. When the distance between the shield and the radiation source is greater than k/2p—with k representing the wavelength of the radiation source—it is in the far-field shielding region. In these instances, the electromagnetic plane wave theory is applied. 

However, when the distance between the shield and radiation source is less than k/2p, it is in the near-field shielding region. In this situation, the theory based on the contribution of electric and magnetic dipoles is applied for the shielding. There are three mechanisms by which electromagnetic wave shielding can occur: absorption, reflection, or multiple reflections. 

Metal Fibers Used in H&V’s Safe-N-Shielded Veils 

Many types of metals are used in EMI shielding, depending on what characteristics the application requires. Popular options include copper, beryllium copper, stainless steel, aluminum, pre-tin plated steel, nickel, Monel, and mu-metal.

Copper

Due to its ability to block both magnetic and radio waves, copper is an ideal material for EMI shielding applications. It is highly malleable and combines easily with other metals for corrosion resistance and improved performance. Copper-based EMI shielding materials are often used in medical devices and computer equipment. 

Beryllium Copper

This alloy combines the beneficial qualities of copper with improved durability and corrosion resistance from beryllium. Tolerating moisture and UV rays, beryllium copper also offers mechanical spring properties that make it suitable for use in applications that must open and close repeatedly. 

Copper Alloy/Alloy 770

Copper alloy 770 is a high tensile strength material consisting of copper, zinc, and nickel. It is corrosion-resistant and highly effective at EMI shielding. While this material does not contain any silver, it is often referred to as nickel silver. 

Stainless Steel 

Stainless steel is a highly corrosion-resistant metal that usually costs less than copper alloys. While stainless steel is stiff and doesn’t offer the same conductivity of copper or other metals, when interwoven with polyester fibers, it performs well as shielding in many home electronics and electrical applications. 

Aluminum

Aluminum is a highly durable EMI shielding material with an excellent strength-to-weight ratio. It is easy to form, resists corrosion, and is cost-effective. 

Pre-Tin Plated Steel

This material is steel that has been coated with a layer of tin to prevent rust. Pre-tin plated steel is a cost-effective solution for protecting against lower EMI frequencies.  

Nickel 

Nickel is an affordable option for protecting against low-frequency EMI. It can be incorporated as a plating or added to other metals to improve their conductivity. 

Monel 

Monel is a nickel and copper alloy, with small amounts of added carbon, iron, silicon, and manganese. Monel is highly corrosion-resistant, offers good conductivity, and exhibits excellent tensile strength and durability. However, it is not recommended for applications where it will come into contact with aluminum. 

Mu-metal 

Mu-metal is a nickel and iron alloy that is suitable for many diverse shielding applications, as it’s effective against both electronic and magnetic fields. 

Why Choose H&V’s EMI Shielding Materials? 

As a global manufacturer of advanced fiber nonwovens, Hollingsworth & Vose has over 30 years of experience solving the world’s most demanding EMI shielding applications. Our solutions reliably reflect and/or absorb radiated electromagnetic energy to protect sensitive electronic and telecommunications systems. To learn more about our EMI/RFI shielding materials, contact us today.