Shielding Effectiveness (dB)
Expresses the reduction of an electromagnetic signal under a defined test setup. Compare values at the relevant frequency range—not just a single headline number.
ENGINEERING SUPPORT
EMI Shielding Fabric Testing & Evaluation
Understand shielding effectiveness, surface resistance and test conditions before selecting conductive textiles for your next project.
WHAT TO EVALUATE
01 / RF PERFORMANCE
02 / ELECTRICAL
03 / APPLICATION
Key Performance Considerations
Laboratory measurements help compare materials, but final performance depends on frequency, construction, seams, grounding and how the fabric is installed. Choose test methods appropriate for the material and the end-use assembly.
Surface Resistance
Provides information about electrical conductivity across a material surface. Report units, electrode arrangement, contact pressure and measurement direction when relevant.
Assembly & Durability
Evaluate seams, overlaps, adhesive interfaces, repeated flexing and environmental exposure as required by the finished product and application.
TEST METHOD CONTEXT
Material Tests vs. Enclosure Tests
| Method / Approach | What it evaluates | Important limitation |
|---|---|---|
| ASTM D4935 | Shielding effectiveness of planar materials using a defined coaxial fixture arrangement. | Only compare results within the method's applicable conditions and frequency range; it does not predict every finished assembly. |
| IEEE 299 | Shielding effectiveness testing of shielding enclosures. | An enclosure method, not a direct substitute for a flat textile specimen test. |
| Electrical resistance measurement | Surface or through-material electrical behavior using an appropriate fixture. | Results depend on geometry, units, contact force, substrate and measurement direction. |
| Application-specific evaluation | Fit, seam continuity, bond quality, durability and installed-system RF performance. | The procedure should reflect the real design and operating environment. |
Important: Mentioning a test method here does not mean every OneThinktec product has been tested to that method, or that any particular product is certified. Ask for documentation applicable to your selected SKU and project.
For more detail, read How Are EMI Shielding Fabrics Tested? and Why Does Shielding Effectiveness Change With Frequency?.
BUYER CHECKLIST
What to Ask for in a Test Report
A useful report should let your engineering team understand how the result was obtained. When available and relevant, request:
- Product / SKU, specimen construction and sample preparation
- Test method, fixture, equipment and test conditions
- Frequency range and shielding effectiveness data or curve (dB)
- Resistance result with units and electrode / contact configuration
- Sample conditioning, test date and identified limitations
- Whether the data represents the material alone or a finished assembly
See also How to Compare Shielding Data and How to Evaluate Shielding Samples.
NEXT STEP
Discuss Your Shielding Requirements
Tell us your intended application, operating frequency, target shielding performance, fabric dimensions and any special environmental or adhesive requirements. We can discuss suitable materials and what supporting information may be available for your selection.