The electromagnetic interface shielding properties of poly(methyl-methacrylate) based composite materials filled with hybrid silver-coated glass microfibers are investigated between 100 kHz and 1 GHz using the coaxial cell method. The incorporation of the ionic liquid EMPy-TFSI (1-ethyl-4-methylpyridinium bis(trifluoromethylsulfonyl)) into the composite material leads to a substantial decrease in the percolation threshold and to an enhancement in the electromagnetic interference shielding effectiveness by more than 60 dB. The addition of EMPy-TFSI, selected for its excellent compatibility with the polymer matrix, allows one to obtain composite materials with shielding effectiveness values up to 116 dB, as compared to a maximum value of 43 dB obtained in the absence of the ionic liquid. This enhancement effect is explained by the interactions between the ionic liquid, the polymer matrix and the silver-coated microfibers that lead to a more efficient percolation network. The use of ionic liquids can represent thus a powerful approach to develop functional composite materials with enhanced interference shielding properties.
The use of Z-transforms in electromagnetic simulations using TLM when dispersive media are present, has been described by Christopoulos [Christopoulos-99] and its efficiency proven. This description concerned cubic meshes. This paper describes a generalization to non uniform meshes. We give the general formulation in this case. To validate our results we apply the algorithm to a gyromagnetic media where a Polder magnetic tensor is used and when this media is included in a rectangular waveguide to obtain non reciprocal effects (isolator). A comparison with experimental results obtained by Gardiol [2] is made.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.