【摘要】 从麦克斯韦方程组出发 ,建立了地质雷达的时域有限差分法 (FDTD)数学模型 ,导出了理想频散关系和超级吸收边界条件。理想频散关系即考虑了FDTD法的收敛性和稳定性 ,也考虑了高频电磁波在Yee氏网格中的传播特点 ;超吸收边界条件则用磁场分量来提高电场分量精度。数值试验表明 ,理想频散关系能真实地反映雷达波在地下介质中的传播规律 ,超吸收边界条件能有效减小截断边界的伪反射 ,提高正演精度。将之应用于实际计算 ,取得满意效果。更多还原

【Abstract】 A forward modeling technique called finite difference tine domain method(FDTD)of ground penetrating radar (GPR) is established by explicit second-order finite-difference approximations on Maxwell’s equations’aideal stability condition and super absorbing boundary condition are proposed in the paper. Except stability and astringency of FDTD,propagation characteristic of EM wave im Yee’s arid is taken account in ideal stability condition,which can suppress numerical dispersion successfully And in super absorbing boundary condition magnetic field is used to increase the precision of electric field ,which can decrease the pseudo reflection of truncating boundaries. Using the theories in forward modeling ,a nicer result is abstained,更多还原