Knitted wire mesh gasket are made of metal wire mesh or metal wire mesh over elastomer core for EMI and RFI shielding of electronic equipment.
Electronic components are generally installed in an enclosure. However, during the installation, there are holes or slots between electronic components and the enclosure, electromagnetic fields will pass through these holes or slots, causing electromagnetic leakage. As the electromagnetic interference or signals increase, these EMI signals may have a negative influence on the device and other vulnerable components in the surrounding equipment, causing various device-related problems, such as degraded performance or even permanent damage. To protect these components, proper shielding measures are required to ensure the safe operation of the system.
Knitted wire mesh gaskets are a kind of effective electromagnetic shielding material to cover these holes or slots to prevent electromagnetic signal leakage and ensure the smooth operation of electrical equipment.
Knitted wire mesh tapes are a kind of double-layer knitted wire mesh tape. Due to its shapes and features, it can be used for the EMI shielding, grounding and electrostatic discharge of cables and cable bunches. Standard EMI shielding tape is made of tin-plated copper clad steel (Sn/Cu/Fe) knitted wire mesh and offers good adaptability to the environment, high tensile strength and good shielding performance.
When wrapping the cable bundles, cover the main cable first and then branch cables. At least 100 mm allowance must be reserved at the beginning and the end. Conductive epoxy resin adhesive can be used for end connection, welding or banding can also be sued for end connection to ensure the knitted wire mesh bandage is evenly wrapped around the cable bunches.
Commonly used material is tin-plated copper clad steel (Sn/Cu/Fe), with a wire diameter of0.114 mm, in compliance with ASTMB–520.
| Material | Magnetic Field | Electric Field | Plane Wave | |
|---|---|---|---|---|
| 100 KHz | 10 MHz | 1 GHz | 10 GHz | |
| dB | dB | dB | dB | |
| Sn/Cu/Fe | 45 | 60 | 40 | 30 |
All-metal knitted wire mesh gaskets are a kind of elastic metal wire mesh strips, generally used as gasket materials and offer effective BMI shielding at the seams of the electronic equipment enclosure. They are often supplied in rectangular, round, round with tail and double round shapes.
For casts or machining parts.
For sheet metal enclosures
For sheet metal enclosures
For sheet metal enclosures
| Material | Magnetic Field | Electric Field | Plane Wave | |
|---|---|---|---|---|
| 100 KHz | 10 MHz | 1 GHz | 10 GHz | |
| dB | dB | dB | dB | |
| Sn/Ph/Bz | 80 | 130 | 95 | 95 |
| Sn/Cu/Fe | 60 | 125 | 80 | 80 |
| Monel | 60 | 125 | 80 | 80 |
Elastomer cored knitted wire mesh gasket is a product combined knitted wire mesh with elastomer cores. The base material is covered with 2 layers of knitted wire mesh. The core material includes neoprene rubber, silicone rubber sponge and rubber tube.
It is easy to remove, relatively softer and can be used in irregular or uneven seams of the electronic enclosure.
The best EMI shielding effectiveness is achieved when the double-layer knitted wire mesh gasket is compressed to 75% of its original height. The shielding effectiveness of the single-layer knitted wire mesh gasket is reduced by 5–10 dB and the shielding effectiveness of knitted wire mesh with double-layer above will not significantly increased.
| Material | Magnetic Field | Electric Field | Plane Wave | |
|---|---|---|---|---|
| 100 KHz | 10 MHz | 1 GHz | 10 GHz | |
| dB | dB | dB | dB | |
| Sn/Ph/Bz | 80 | 130 | 95 | 95 |
| Sn/Cu/Fe | 60 | 125 | 80 | 80 |
| Monel | 60 | 125 | 80 | 80 |
Compressed knitted wire mesh gasket is formed by die-compressing a certain amount of knitted wire mesh gasket that contains no joints or splices, featuring excellent EMI shielding effectiveness, adjustable density (14%–20%), good performance, low price and easy installation.
Although most common are rings, gaskets can also be produced in rectangular or special shapes with holes or mounting recesses, corner radii, and other custom features.
