EMC gaskets – development trends

Telecom technologies has since the early 90´s increased the demands of EMI shielding. The products have been frequently used in radio base stations, microwave transmission systems and short distance communication devices. With close cooperation between the companies, in both material development and gasket design, sustainable solutions have been added into the market’s applications. Common solutions in these are dispensed FIP (form-in-place) gaskets, extruded gaskets and molded gaskets. All based on silicone as the main raw material. 

FIP EMC gasket

A dispensed gasket is formed in placed on a metal or plastic cover, creating electromagnetic compatibility by deforming true compression between the cover and a PCB or other electrically conductive surfaces. Emerging from this, a great cost saving potential can be found in designing the gasket as soft as possible to reduce the pressure on the PCB, cover and fasteners.

Trishield 2.0 has through the years been developed to the softest form-in-place gasket in the world, with great benefits compared to a regular D-shaped dispensed gasket.

• 50% less material consumption
• 75% lower compression force
• 40% less fasteners / screws needed
• 5% increased PCB area
• 100% more tolerance absorption
• 90-degree corners allowed
• Market leading shielding of 110dB
  
  

This solution also enables a fully automated process from the application of the gasket onto the cover, until the final assembly at customer production site, making it a great choice when manual assembly is not preferable.

Molded EMC gasket

A molded conductive gasket enables a more complex design of the gasket’s geometry. Nolato has developed processes to combine multiple materials in molding. Electrically conductive material can be combined with pure silicone to achieve a gasket that will shield both electromagnetic radiation and environmental strains. A plastic carrier can be used in combination with conductive silicone material to strengthen the gasket in one or two directions, and still allow it to be flexible in its compressed direction.

Extruded EMC gasket

An extruded gasket is a good choice when fast time to market is preferable as a proven concept where electromagnetic shielding can easily be combined with environmental protection. The two-material extrusion with pure silicone material towards the environmental strains is protecting the thin layer of conductive silicone rubber, and most importantly the enclosed electronics.

Furthermore, functions can be designed in the profile of the extruded gaskets. For example, a press-fit feature allowing the gasket placed in the groove firmly adhered without risks of falling out during transportation and handling, with no added cost related to adhesive.

Nolato’s new Compashield 2.0 with even thinner, more flexible and higher conductivity enables a softer gasket in your application with a significant higher EMI shielding effectiveness.

• 20% lower compression force
• 50% improved electrical resistance
• 70% more stable after aging
• 100% stronger tensile strength
• 30% more bounce back

Increasing frequencies

Nolato’s history of involvement in EMI shielding have now started to move from frequencies in the range 30MHz – 7GHz, towards applications with radiated frequencies at 28GHz and above. With increasing frequencies, wave lengths are decreasing. This adds requirements to the choice of the solution, to be more flexible and reliable over time. Conductive silicone gaskets is an excellent choice in these areas.

Since electromagnetic compability have become an important requirement also in automotive electronics as an evolution of vehicles increased intelligence and connectivity (IoT). Nolato’s gaskets have been implemented in a variety of electrical products, exposed to frequencies up to 77GHz and narrow wavelengths. Despite these harsh environments for electromagnetic shielding, the gaskets are still performing excellent. Nolato continues to contribute customer value in the physical challenges ahead, towards an ever more connected world.