FDTD方法吸收边界条件的研究及应用

Research on Absorbing Boundary Condition in FDTD Method and Its Application

用时域有限差分法(FDTD)求解电磁散射问题中,吸收边界条件的设置起着关键性作用。通过时间和空间上的递推算法对时域有限差分法中的两种吸收边界条件:Mur吸收边界条件和完全匹配层(PML)的吸收效果进行了比较和分析。同时,引入参数对PML的差分方程进行了优化,避免了将电磁场分裂为两个分量进行计算,进而降低了计算内存开销。实验结果证明PML具有更优越的吸收性能。最后,在FDTD算法中应用PML吸收层对一圆柱形导体的雷达散射截面积(RCS)进行数值仿真,验证了FDTD算法在计算雷达散射截面积(RCS)上的有效性。

The absorbing boundary condition plays an important role in Finite-Difference Time-Domain（FDTD） method to solve the problem of electromagnetic scattering.The two absorbing boundary conditions in FDTD method：Mur and Perfectly Matched Layer（PML）,and their performances are compared and analyzed by using the recursion algorithms in time domain and spatial domain.In addition,by introducing parameters,the PML difference equations are optimized to avoid calculating by individing the electromagnetic field,the apparent advantage is reducing the computing costs.The experiment demonstrates that the PML has better absorbing performance.Finally,the radar cross section（RCS） of a cylinder conductor is simulated by FDTD method with PML absorbing boundary condition.The experimental results show that FDTD method is effective in the calculation of RCS.