Hybrid FEM-BEM Unified Boundary Condition with Sub-Cycling for Electromagnetic Radiation

摘要

Hybrid solutions to time-domain electromagnetic problems offer many advantages when solving open-region scattering or radiation problems. Hybrid formulations use a finite-element or finite-difference discretization for the features of interest, then bound this region with a layer of planar boundary elements. The use of volume discretization allows for intricate features and many changes in material within the structure, while the boundary-elements provide a highly accurate radiating boundary condition. This concept has been implemented previously, using the boundary elements to set the E-field, H-field, or both for an FDTD grid, for example in (1)(2)(3), or as a mixed boundary condition for the second order wave equation solved by finite elements (4). Further study has focused on using fast methods, such as the Plane Wave Time Domain method (3)(4) to accelerate the BEM calculations. This paper details a hybrid solver using the coupled first-order equations for the E and H fields in the finite-element region.