Numerical calculation of 3 mm wave extinction for expanded graphite

In order to explore the extinction and scattering characteristics of expanded graphite, which is a kind of 3 millimeter wave interference materials, the formula of extinction, scattering, absorption and backscattering cross sections (radar cross. section, RCS) are established based on the electromagnetic scattering theory of cylindrical conductor of finite length and finite conductivity by the method of moment. The extinction and scattering characteristics are calculated, and the influening factors of the characteristics including length, radius, conductivity and magnetic permeability of the expanded graphite are analyzed using Mathematica program. Results show that the expanded graphite has excellent extinction and scattering properties when its length and radius are 1.5 mm and 0.5 mm, respectively, and the properties can be improved when the conductivity and magnetic permeability of the expanded graphite are increased properly. This research provides a valuable insight into the improvement of interference performance of expanded graphite in 3 millimeter wave.