Resistive Sheet Boundary Condition-Based Nonconformal Domain Decomposition FE-BI-MLFMA for Electromagnetic Scattering From Inhomogeneous Objects With Honeycomb Structures

• Published in: IEEE transactions on antennas and propagation Vol. 70; no. 10; pp. 9483 - 9496
• Main Authors: Yang, Zeng, Yuan, Xiao-Wei, Huang, Xiao-Wei, Yang, Ming-Lin, Sheng, Xin-Qing
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antenna arrays; Approximation; Boundary conditions; Cellular structure; Decomposition; Domain decomposition methods; Electromagnetic scattering; Finite element analysis; Finite element method; High definition; honeycomb structure; Honeycomb structures; hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA); Mathematical analysis; Mesh generation; Microwave absorption; Multilayers; Multipoles; nonconformal domain decomposition; Nonhomogeneous media; Numerical models; Operators (mathematics); Radomes; resistive sheet boundary condition (RSBC); Resistive sheets; Surface impedance; Unit cell
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2022.3177565

A flexible and efficient resistive sheet boundary condition (RSBC)-based hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) is presented for computing electromagnetic scattering from inhomogeneous objects with microwave-absorbing honeycomb structures. In the proposed algorithm, each nonmagnetic and high lossy material coated unit cell wall of the honeycomb is first approximated by the multilayered RSBC as a zero-thickness resistive sheet to eliminate the computational burden due to the extremely thin and multilayered characteristics of the coated unit cell wall. Then, the RSBC is incorporated into the FE-part of the FE-BI-MLFMA formulation. To further reduce the burden of meshing complicated objects involving cellular structures after RSBC approximation, the hybrid conformal and nonconformal domain decomposition method (DDM) of the FE-BI-MLFMA, which integrates the nonconformal Schwarz DDM-FE and the simplified discontinuous Galerkin (S-DG), is employed to bring significant flexibility and versatility in geometry modeling and mesh generating. An effective block low-rank multifrontal solver-based domain decomposition finite-element method (FEM)-absorbing boundary condition (ABC) preconditioner is constructed to speed up the solution of the FE-BI equations using locally approximated integral operators for the BI part. Numerical examples are given to demonstrate the accuracy, capability, and performance of the proposed algorithm, including a high-definition complicated fighter model with antenna array, multilayer dielectric radome, and microwave-absorbing honeycomb structures.