FDTD中的一种新截断边界-STWBC

Standing-traveling wave boundary condition (STWBC) for finite-difference time-domain mesh truncation

提出了一种新的截断边界条件 :驻波 -行波边界条件 ( STWBC)。这种截断边界条件是在计算域外附加理想导电 (磁 )壁进行截断 ,运用反射原理 ,将边界处的驻波转化为行波 ,保持计算域内的行波状态 ,在有限空间内有效模拟出无限大的电磁散射空间。给出了该截断边界条件在 FDTD中的差分迭代式 ,以及二维和三维数值实验结果 ,并与 PML边界和单向波边界进行了比较。由于该截断边界比单向波边界所需计算空间小 ,数值稳定性好 ,同时不象 PML边界 ,需要进行场量分离和附加额外的吸收层 ,因此计算效率较高。

Standing-Traveling Wave Boundary Condition (STWBC) is developed to truncate the computational domain without reflection. The perfect electric conducting (PEC) termination was used. Unlike the PML, no additional absorbing region surrounding the domain of interest is needed. With STWBC, the standing wave on the boundary is transformed to the traveling wave, and creates no reflections. Numerical examples demonstrate that the FDTD implementation of the STWBC technique is stable, and independent of the incident angle of the outwardly traveling wave. As Compared to PML, it allows us to obtain a little lower accuracy but a great release of computational requirements, thus it is more computationally efficient for a big target.