First order models for thin-material sheets and coatings in the finite-element time-domain method

The ability to model complex electromagnetic phenomena accurately represents an important aspect of the computational sciences. Accurately predicting electromagnetic propagation and interaction is an emerging technology that is becoming increasingly important to application areas such as wireless communication, antenna analysis and design, microelectronics, radar suppression, and electromagnetic compatibility and interference (EMC and EMI). The ability to model fine system detail is increasingly important because small features can often significantly affect the overall system response. This is particularly true in the case of thin-material sheets and coatings, which is the topic of the paper. To address this length-scale variation issue, first-order impedance boundary conditions (IBC) for the finite-element time-domain (FETD) method are presented. Although IBCs have been widely used in the moment method, the finite-difference time-domain (FDTD) algorithm, and the frequency-domain finite-element method (FEM), a concise collection of IBCs for the FETD formalism has not previously appeared in the open literature.