由电磁学的基本规律麦克斯韦方程差分形式即时域有限差分(Finite Different Time Domain,FDTD)导出不均匀网格的FDTD差分形式,即不均匀网格的时域有限差分法(Non Uniform Grid Finite Different TimeDomain,NU-FDTD),并提出了在腔体孔...由电磁学的基本规律麦克斯韦方程差分形式即时域有限差分(Finite Different Time Domain,FDTD)导出不均匀网格的FDTD差分形式,即不均匀网格的时域有限差分法(Non Uniform Grid Finite Different TimeDomain,NU-FDTD),并提出了在腔体孔缝电磁耦合分析中采用NU-FDTD时,网格和时间步长划分的原则是:导体边界采用局部均匀细网格法,其它空间采用渐变不均匀法。实验结果表明,这种方法不仅节省计算时间,而且精度高。展开更多
With the linear interpolation method, an improved absorbing boundary condition（ABC）is introduced and derived, which is suitable for the alternating-direction-implicit finite- difference time-domain （ADI-FDTD） meth...With the linear interpolation method, an improved absorbing boundary condition（ABC）is introduced and derived, which is suitable for the alternating-direction-implicit finite- difference time-domain （ADI-FDTD） method. The reflection of the ABC caused by both the truncated error and the phase velocity error is analyzed. Based on the phase velocity estimation and the nonuniform cell, two methods are studied and then adopted to improve the performance of the ABC. A calculation case of a rectangular waveguide which is a typical dispersive transmission line is carried out using the ADI-FDTD method with the improved ABC for evaluation. According to the calculated case, the comparison is given between the reflection coefficients of the ABC with and without the velocity estimation and also the comparison between the reflection coefficients of the ABC with and without the nonuniform processing. The reflection variation of the ABC under different time steps is also analyzed and the acceptable worsening will not obscure the improvement on the absorption. Numerical results obviously show that efficient improvement on the absorbing performance of the ABC is achieved based on these methods for the ADI-FDTD.展开更多
文摘由电磁学的基本规律麦克斯韦方程差分形式即时域有限差分(Finite Different Time Domain,FDTD)导出不均匀网格的FDTD差分形式,即不均匀网格的时域有限差分法(Non Uniform Grid Finite Different TimeDomain,NU-FDTD),并提出了在腔体孔缝电磁耦合分析中采用NU-FDTD时,网格和时间步长划分的原则是:导体边界采用局部均匀细网格法,其它空间采用渐变不均匀法。实验结果表明,这种方法不仅节省计算时间,而且精度高。
基金The National Natural Science Foundation of China(No.60702027)the Free Research Fund of the National Mobile Communications Research Laboratory of Southeast University (No.2008B07)the National Basic Research Program of China(973 Program)(No.2007CB310603)
文摘With the linear interpolation method, an improved absorbing boundary condition（ABC）is introduced and derived, which is suitable for the alternating-direction-implicit finite- difference time-domain （ADI-FDTD） method. The reflection of the ABC caused by both the truncated error and the phase velocity error is analyzed. Based on the phase velocity estimation and the nonuniform cell, two methods are studied and then adopted to improve the performance of the ABC. A calculation case of a rectangular waveguide which is a typical dispersive transmission line is carried out using the ADI-FDTD method with the improved ABC for evaluation. According to the calculated case, the comparison is given between the reflection coefficients of the ABC with and without the velocity estimation and also the comparison between the reflection coefficients of the ABC with and without the nonuniform processing. The reflection variation of the ABC under different time steps is also analyzed and the acceptable worsening will not obscure the improvement on the absorption. Numerical results obviously show that efficient improvement on the absorbing performance of the ABC is achieved based on these methods for the ADI-FDTD.
