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We provide a model able to predict the shielding effectiveness (SE) of carbon fiber composite (CFC) panels made of stacked layers of conducting fibers. This model permits us to obtain simple formulas in which the only parameters needed are the sheet square resistance and the effective panel thickness. These tools let us to predict a minimum SE, which always increases with the frequency and therefore constituting the worst case, from an electromagnetic shielding perspective. Consequently, the measurement of minimum SE requirements can be simply measured with a micro-ohmmeter using an specific experimental setup which is also described here. Additionally, this method allows to measure very high SE falling far beyond the dynamic range of the values measurable with the most commonly used standard, the ASTM D4935. After describing the modeling technique and the different test setups used, a cross-validation between theoretical and experimental results is made for four different samples of CFC; two designed to test the modeling assumptions and two which are representative of the ones nowadays used in a real aircraft.

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The tendency over the last decades in the aerospace industry is to substitute classic metallic materials with new composite materials such as carbon fiber composites (CFC), fiber glass, etc., as well as adding electronic devices to ensure the safety and proper platform operation. Due to this, to protect the aircraft against the Electromagnetic Environmental Effects (E3), it is mandatory to develop accurate electromagnetic (EM) characterization measurement systems to analyze the behavior of new materials and electronic components. In this article, several measurement methods are described to assess the EM behavior of the samples under test: microstrip transmission line for a surface current analysis, free space to obtain intrinsic features of the materials and shielding effectiveness (SE) approaches to figure out how well they isolate from EM fields. The results presented in this work show how the different facilities from the National Institute of Aerospace Technology (INTA) are suitable for such purposes, being capable of measuring a wide variety of materials, depending on the type of test to be carried out.

Efficiently modeling thin features using the finite-difference time-domain (FDTD) method involves a considerable reduction in the spatial mesh size. However, in real-world scenarios, such reductions can lead to unaffordable memory and CPU requirements. In this manuscript, we present two stable and efficient techniques in FDTD to handle narrow apertures on conductive thin panels. One technique employs conformal methods, while the other utilizes subgridding methods. We validate their performance compared to the classical Gilbert-Holland model and present experimental results in reverberation environments to shed light on these models’ actual confidence margins in real electromagnetic compatibility (EMC) scenarios.