Improved Surface Impedance Absorbing Boundary for FDTD Method

An improved absorbing boundary condition for terminating finite-difference time-domain (FDTD) simulations, based on the surface impedance concept, is proposed in this paper. The improved method uses E component collocation instead of the H component collocation as in [1]. The performance of the two SIABCs and 10-layers CPML are discussed with a 3D example which employed these absorbing boundary conditions (ABCs) in the calculation of RCS of a dielectric sphere. The computer resources requirements are also discussed. The compared result indicates that both the SIABCs have a comparable absorbing performance with 10-layers CPML, and the E component collocated SIABC has a better absorbing performance relative to H component collocated SIABC.