Fabric over Foam Gaskets: Full Analysis of Resistivity, Shielding Effectiveness, and Compression Performance

In modern electronic device design, selecting the right EMI shielding material is critical. Among the available options, Fabric over Foam Gaskets (FoF Gaskets) stand out for their unique structure and outstanding performance. This article explores the three core indicators—resistivity, shielding effectiveness, and compression performance—and explains why FoF gaskets are favored across industries.

1. Resistivity: The Key Parameter for Conductivity

Resistivity, measured in Ω/sq, defines a gasket’s conductivity. Lower resistivity indicates better conductivity, essential for efficient EMI shielding.

Advantages of FoF Gaskets:

• Multi-directional contact design: The wrapped structure forms a continuous conductive layer around module edges, reducing high-impedance zones.

• Recommended values: For high-frequency applications, surface resistivity should be ≤0.1Ω/sq to ensure a reliable low-impedance grounding path.

👉 For more on how different metallic coatings affect resistivity, see Metal-Coated Conductive Foam: Advanced EMI Shielding Technology Explained.

2. Shielding Effectiveness: From Point Shielding to Full Edge Sealing

Shielding effectiveness (SE), measured in dB, represents the attenuation capacity of a material. Traditional planar adhesives often struggle with uniform shielding in complex assemblies, while FoF gaskets provide continuous coverage.

FoF Gaskets Shielding Mechanism:

• 360° continuous shielding: Forms a closed conductive loop around edges, effectively suppressing slot radiation.

• Measured results: Nickel-copper FoF gaskets achieve 65–80dB SE in the 1–6GHz range—8–12dB higher than strip-shaped foams of similar thickness.

3. Compression Performance: Ensuring Long-Term Reliability

Compression performance determines recovery ability and sealing reliability over time. FoF gaskets combine mechanical resilience with EMI protection, making them ideal for demanding environments.

Typical compression data:

• Compression rate: 40% (ASTM D3574)

• Recovery rate: 92%

• Base materials: PU foam, silicone rubber, and others—selected based on application needs.

4. Application Scenarios and Selection Guidance

Building on How to Select the Right Type of Conductive Shielding Foam for Your Application?, here’s how FoF gaskets perform in real-world scenarios:

• High-frequency devices: Require low-resistivity and uniform conductive pathways.

• Industrial control panels: Benefit from high durability and excellent compression recovery.

• Wearable devices: Gain lightweight shielding without compromising heat dissipation.

• Outdoor telecom base stations: Ensure long-term sealing against humidity and salt fog.

Conclusion

Through detailed analysis of resistivity, shielding effectiveness, and compression performance, it’s clear that Fabric over Foam Gaskets (FoF Gaskets) excel in EMI shielding and mechanical stability. They are particularly suitable for high-frequency electronics, industrial systems, wearable devices, and outdoor communication equipment.

As technology advances, FoF gaskets are expected to play an even greater role in emerging applications. For more insights into conductive foam materials and EMI shielding solutions, explore our technical library.