Limitations in the Shielding Effectiveness Measurement Methods for Carbon Fiber Composites

Novel materials, as multi-ply carbon fiber composites (CFC), are increasingly used in the industry due to their outstanding mechanical properties in relation to their weight. In this regard, from the standpoint of electromagnetic compatibility (EMC), shielding effectiveness (SE) is a key parameter that often determines the scope for application of a given material. This article addresses the application of two complementary standards, ASTM D4935 and IEC 61000-4-21, to the SE measurement of different CFC test samples with more than 10 layers and a very large expected shielding. The analysis of the limitations encountered and the description of applied improvements on the traditional measurement procedures on each method are also included, showing promising results. On the other hand, there are alternative methods to evaluate the SE of CFC based on their DC square resistance. Consequently, and forthe shake of completeness, a novel setup for high precision measurement of the DC square resistance of CFC samples is also described along the article.