The Impact of Pore Diameters, Pore Randomness, and Void Fraction on the EMI Shielding of Polyurethane Foams

This paper presents a novel approach to analyze the electromagnetic interference (EMI) shielding effectiveness (SE) of polyurethane (PU) foam geometries, which are built in Blender software and simulated using CST Studio software. Three different batches of geometries were built to investigate the impact of void fraction, pore diameters, and pore randomness of PU foam on the SE, reflection coefficient (S11) and electromagnetic absorption in the 26.5–40 GHz frequency range. The observed resonance frequency decreased with decreasing pore diameters and void fraction. Decreasing the pore diameter, increasing the pore randomness, and decreasing the void fraction enhanced the SE in the frequency range between the resonance frequency and 40 GHz. The EM absorption increased with increasing the pore diameter and randomness but decreased with increasing the void fraction. This study also presents simulations and measurements of Polytetrafluoroethylene (PTFE) and PU foam materials. The simulation results were compared with the measured ones obtained using vector network analyzer measurements to verify CST Studio's ability to accurately calculate the EM parameters. The measured and simulated results were in good agreement, confirming the accuracy of the results obtained using CST Studio. Our new parametric study fills a gap in existing literature since it combines for the first time an open‐source 3D software for 3D rendering with an electromagnetic simulator to evaluate the impact of the pore topography (void fraction, diameter, randomness, etc.) on the EMI shielding performance of PU foams.