Shielding Effectiveness Measurements of Drywall Panel Coated with Biochar Layers

Shielding against electromagnetic interference (EMI) is a critical issue in civil applications generally solved with metal screens. In recent years, the properties of many composite materials filled with carbon nanotubes or graphene or materials with a carbon-based coating have been analysed with the aim of using them for electromagnetic shielding applications. Among other carbon materials, biochar, derived from biomass and characterized by high carbon content, emerges as a sustainable, renewable, environmentally friendly, and inexpensive material. In this paper, commercial biochar thermally treated at 750 °C is used to coat with several layers common building components such as drywall panel. Shielding effectiveness is measured in the frequency band 1–18 GHz for normal incidence and skew angles 10, 20 and 30 deg in a full anechoic chamber with double ridged, vertically and horizontally polarized broadband horn antennas. The results show that the proposed biochar-coated drywall panels provide a good shielding effectiveness compared to similar solutions, with the advantage of a less expensive and easier to realize building material.