Efficient Modeling of Wave Propagation Through Rough Slabs with FDTD
With 5G communication systems along with several radar and imaging technologies employing millimeter waves, accurately modeling wave propagation at these frequencies is as important as ever. At these frequencies, surface roughness of waveguide components (a side effect of both standard fabrication and 3-D printing) has a pronounced role. Yet, in FDTD, this effect is still modeled through the time-consuming Monte-Carlo method. This paper presents a new approach with distinct advantages over the state of the art. Reflection and transmission through rough slabs is modeled with FDTD and an efficient polynomial chaos expansion of the statistical fields in and around the rough surface. We demonstrate the computational efficiency and accuracy of this technique, which can model both the usual excess attenuation due to small-scale roughness and diffuse scattering effects.