移动坐标系FDTD方法在脉冲波传播中的应用

通过在时域有限差分(FDTD)方法中引入移动坐标系,解决了一般FDTD方法处理脉冲长距离传播时面临的困难。推导了移动坐标系下的场方程和FDTD差分格式,并将该方法应用于模拟波导中电磁脉冲的传播。计算结果表明,在传播过程中,脉冲波包沿传播方向逐渐展宽,脉冲的峰值场强变小,同时出现了色散现象,脉冲中传播较慢的成分逐渐移向尾部,产生带尾态,这与一般FDTD方法得到的计算结果接近。多个频率的计算结果表明,该方法与一般FDTD方法得到的数据的相对误差小于0.1%,验证了方法的可行性和正确性。

Application of moving coordinate FDTD method to electromagnetic pulse propagation

The moving coordinate frame finite-difference time-domain (FDTD) method is developed to simulate the propagation of electromagnetic pulses over long distances. The discretized form of moving coordinate frame FDTD scheme in three dimensions is given, and is applied to calculate the propagation of different pulses in rectangular waveguides. The widths of pulses in propagation direction increase when the pulses propagate in the waveguide. Dispersion phenomena appear, and slow parts of the pulses move to the pulse tail. Result comparison between conventional FDTD method and moving coordinate frame FDTD method shows the relative error of less than 0.1%. The proposed method is shown to be accurate with a considerable reduction in time and memory consumption.