减缩时域有限差分法在电磁干扰预测中的应用

Application of reduced finite difference time domain method to the prediction of electromagnetic interference

对减缩时域有限差分 (R FDTD)法进行了改进 ,采用传统时域有限差分 (FDTD)法计算导体和源网格处的电场 ,其余网格处的电场采用R FDTD法计算 .细导线附近网格上的磁场也采用传统FDTD法计算 ,这样可以消除直接利用R FDTD法计算时长时间迭代后出现的不稳定性 .用这种改进的R FDTD方法分别对一个在导体壁上开有水平和垂直缝隙的矩形屏蔽外壳的电磁干扰进行了预测 ,得到了屏蔽外壳激励源的输出功率曲线和屏蔽外壳的泄漏功率曲线 。

The reduced finite difference time domain (R-FDTD) method is improved. The electric-field components at the perfect electric conductor (PEC) cells and the source cells are calculated with Yee's FDTD to simplify the computation, and the electric fields of the rest source-free region are modeled with R-FDTD. The magnetic-field components near thin wire are modeled with regular FDTD and the magnetic fields in the other region are computer with R-FDTD. In this way, the numerical instability occurred in the late step of updating magnetic fields near thin wire by original R-FDTD can be efficiently eliminated. Electromagnetic interference from a rectangular shielding enclosure with a horizontal slot and a vertical slot is modeled with the improved R-FDTD, respectively. The curves of delivered power and radiated power through the slots are obtained. The simulated results agree well with the experimental data published in literature.