A Fast Computation Method for Solving Scattering from Complex Objects with Radar Absorbing Honeycomb Structure

In this paper, we present a fast and accurate method for solving electromagnetic scattering from complex objects with honeycomb radar absorbing structures based on the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA). In this method, the extremely thin walls of the dielectric honeycomb are approximated by the impedance boundary conditions (IBC) and then are reduced to a zero-thickness resistive sheets, thus the main computation burden for computing field interaction with honeycomb structure is eliminated. Then, it is incorporated into the FE-part of the FLBI-MLFMA formulation, with effective high-efficiency finite element-absorption boundary (FEM-ABC) based preconditioner to speed up the solution of the FLBI equations. A series of numerical examples are given to demonstrate the accuracy and performance of the proposed method, including a complicated practical missile-like object involving radar-absorbing honeycomb structures.