【摘要】 采用时域有限差分（ＦＤＴＤ）法数值模拟电磁脉冲波的入地传输，以及地下二维目标的瞬时散射，详细讨论了ＦＤＴＤ法中主要参数的取值原则．在稳定条件下所取时间间隔随波进入不同煤质而不同，以满足因果律．通过数值计算证明，在无耗空间得到的吸收边界条件也适用于有耗媒质．数值模拟在地面接收到的地下目标的回波响应与有关文献的结果一致．更多还原

【Abstract】 The FDTD method Is to simulate numerically the transmission of EM pulse wave into ground and the transient scattering by underground 2-D target. How to choose the main parameters in FDTD method is discussed in detail. Under the steady condition, the time setp △t is assumed to vary with the waves propagating in different mediums,so as to meet the law of cause and effect.The obsorbing boundary conditions obtained in lossles space are proved to be suitable fis well in lossy medium by munerical calculation. Numerical results of the echo response of the underground target are well apree with those of the other papers.更多还原