The answers below are intended for early material selection and project discussion. Real-world shielding should be validated in the finished assembly under the intended test conditions.
What is surface resistance?
Surface resistance describes how easily electrical current can travel across the material surface. It is usually reported in ohms or ohms per square depending on the test method.
Does lower surface resistance always mean higher shielding effectiveness?
Not necessarily. Good conductivity is important, but shielding effectiveness also depends on frequency, construction, thickness, continuity, test geometry and how the material is installed.
When is surface resistance especially important?
It matters when the fabric must make low-resistance contact with another conductive surface, such as an enclosure seam, gasket interface, grounding point or laminated conductive layer.
What should a buyer ask for besides surface resistance?
Ask for the test method, shielding effectiveness by frequency, material construction, width, thickness, coating or plating system, environmental requirements and the intended assembly method.