Efficient Evaluation of Equivalent-Principle Sources in MoM-FDTD Hybrid Method by Employing Spatial Interpolation and Adaptive Sampling

MoM-FDTD hybrid approach requires the information to be exchanged forth and back between the MoM-regions and the FDTD-regions coupled through the Huygens' surfaces. For electrically large structures, evaluation of the electric and magnetic field components and related equivalence-principle sources on the Huygens' surfaces can represent a significant (even dominant) fraction of the total solution time required for the problem. In this paper, we demonstrate a possibility of increasing computational efficiency of the MoM-FDTD hybrid method by employing spatial interpolation combined with adaptive sampling in calculating the electric and magnetic field components and the effective sources on the Huygens' surfaces. Numerical examples show that the proposed approach offers a considerable CPU time saving.