Attached herewith are the plots of complex permittivity and permeability of carbon foam containing in situ SiC nanowiresThe values increase with the increase in nanowires contents. Are such a high values suitable for EM shielding? Further how these plots can be analyzed? Thanks for kind help.
Complex permittivity data are usually analysed in Cole-Cole plots where you plot the imaginary part of epsilon vs. the real part of epsilon. Your values seem to be extraordinary high. How did you measure them?
This is a novel carbon foam containing in situ grown Si nanowires. The EMI shielding properties were measured using a vector network analyzer (VNA; MS4644A, Anritsu, Kana-gawa, Japan) by fixing the carbon foam in the cavity of a wave guide. The rectangular carbon composite foam samples of dimensions 22.7 mm × 10.2 mm × 5 mm were used for the measurement. An electromagnetic wave was directly injected the carbon foam and the values of scattering parameters (Sij-parameters; S11, S12, S21and S22) were measured for the frequency scanned from 8.2–12.4 GHz(X band) using the corresponding waveguides.
so you seem to have a diamagnetic, lossy conductor type material. Read the brief Wikipedia entry about the Cole-Cole equation - it's quite short but good. I would expect what you measured only for an ionic material but Si bounds are covalent... it would be interesting to use the sample with lots of nanowires to study by EELS in a TEM - you would get the dielectric response above 1e14 Hz (in the lectronic relaxation range) which should extend your 1e9-1e10 Hz range.
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