A flexible and efficient approach for computing electromagnetic scattering by honeycomb radar absorbing structures

A flexible and efficient numerical modeling approach is presented for simulating electromagnetic scattering from honeycomb radar absorbing structures (RAS). In the proposed approach, the original honeycomb structure is divided into the homogenization-based and the resistive sheet boundary condition approximation-based two subregions. The former is homogenized as a diagonal anisotropic medium in local coordinate system by using the Hashin-Shtrikman variational theory and a Euler rotation matrix for describing its orientation in the global coordinate system, while the latter is approximated by reducing each unit cell wall as a zero-thickness resistive sheet by using the resistive sheet boundary condition (RSBC). The hybrid model is then simulated by using the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA). Numerical results show that the proposed approach exhibits high accuracy and flexibility of the RSBC based numerical modeling approach, and efficiency of homogenization-based approach.