Electromagnetic scattering characteristics of DNM rough surface in the terahertz regime by the FDTD algorithm

Wide band electromagnetic (EM) scattering characteristics of randomly rough surface in the terahertz (THz)frequency range are investigated through the use of finite difference time domain(FDTD) algorithm. Then the scattering characteristics of double negative materials(DNM) randomly rough surface are investigated further. It's worth nothing that in order to avoid introducing numerical divergence, setting the negative permittivity and negative permeability of the negative material region indirectly is necessary. By using the constitutive relation and the transform relation of time domain and frequency domain, the two dimensional (2-D) differential equations in FDTD are obtained.