Microwave Dielectric Properties of Tannin-Based Carbon Foams

摘要

Dielectric analysis of tannin-based carbon foams with different pore sizes, produced at different densities, was carried out in wide microwave frequency range (8GHz - 35GHz). Both dielectric permittivity and electrical conductivity of carbon foams at 8GHz, were high, i.e. more than 70 and close to 10 S/m respectively, and increased with carbon foams density according to power laws. High microwave complex dielectric permittivity values of carbon foams reported here, along with other valuable properties such as "green" origin, low price, lightness, chemical inertness, thermal stability and high conductivity in static regime, open new routes for producing effective electromagnetic shields and filters from tannin-based carbonaceous porous structures.