Fast Simulation of Resonant and Conformal Metasurfaces Using DGTD-GSTC Method

A discontinuous Galerkin time-domain (DGTD) method incorporating generalized sheet transition conditions (GSTCs) is improved for fast simulation of resonant and conformal metasurfaces. Existing DGTD-GSTC method replaces the metasurfaces’ subwavelength physical structure with surface susceptibilities, thereby avoiding the dense meshes and enabling fast time-domain simulations of curved metasurface. However, this method is limited to only non-resonant structure. To accurately simulate the resonant behavior of metasurfaces, we employ the complex-conjugate pole-residue (CCPR) dispersion model to fit the frequency-dependent surface susceptibilities and incorporate it into the existing DGTD-GSTC framework using the auxiliary differential equation (ADE) method. Furthermore, this paper addresses two key issues in GSTC-based simulation. First, the impact of normal components of surface susceptibility on stability is rigorously analyzed. These components are essential for accuracy but omitted in previous time-domain method due to a lack of stability analysis. This paper identifies the underlying mechanism of instability and proposes a corresponding suppression method. Second, the surface susceptibilities retrieval method for metasurface at media interfaces is provided, adopting the DGTD-GSTC method to conformal scenarios. Three representative examples are presented, along with comparisons to commercial software results in terms of accuracy and computational resources, highlighting the accuracy and efficiency of the developed DGTD-GSTC method for simulation of resonant and conformal metasurfaces.