Evaluation of Absorbing Material Shielding Effectiveness Using a Baum–Liu–Tesche Based Method

Abstract The shielding efficacy of the metal cavity can be effectively enhanced using absorbing materials coated on the inner wall of the cavity. With highly potential materials such as graphene, silicon carbide (SiC), polytetrafluoroethylene (PTFE), and Ni/rGO in shielding, an analytical method based on the Baum–Liu–Tesche (BLT) equation is proposed to evaluate their shielding effectiveness (SE) in the open cavity. Compared to the electromagnetic field simulation software, i.e., CST Studio Suite, the resonant frequency of the coated cavity using the proposed model can be obtained with an average error of no more than 8 dB. The findings reveal that PTFE with a 1 mm thickness coated on the inner wall of the cavity can achieve the best shielding effect, but the resonant frequency of the cavity remains unchanged. On the other hand, the increased material thickness by adding the other three materials has no effect on the frequency located at the resonance modes of TE101 and TE102, except for the high-order resonance TE103. However, it is found that when a 2 mm thickness of these three materials is coated, the shielding ability achieves its best status. It verifies that the proposed BLT analytical method presents superiority in terms of computational rapidity and accuracy, with fewer resources occupied.