An Efficient Scheme for Multiple Fine Structures in Hybrid FETD

In this paper, an efficient scheme is proposed to apply the hybrid finite-element time-domain method for electromagnetic model of multiple fine structures. The unconditionally stable finite-element time-domain (US-FETD) method is used in every subdomain separately. Since the matrices constructed in every fine structure subdomain are small, the unstable modes can be obtained by the generalized eigenvalue problem in every fine structure subdomain. If the fine structures are the same, obtaining unstable modes in one subdomain will further improve the efficiency. Compared to the eigenvalue problem containing all fine structures, the proposed scheme costs less memory and time for eigenvalue analysis. Numerical results show the effectiveness of the proposed scheme.