波导中模式吸收边界条件的计算方法

Method of Calculating Modal Absorbing Boundary Condition for Waveguide Problems

本文对基于波导中模式冲击响应构造，并应用于时域有限差分（FDTD）方法的 模式吸收边界 条件，进行了详细地计算和分析.本文应用高阶插值方法，显著地提高模式吸 收边界条件计 算的精度，采用点匹配法鉴别模式幅度，加快了计算模式吸收边界条件的速 度.计算结果表 明，采用模式吸收边界条件可以有效地减少FDTD方法中的节点数目，从而提 高了FDTD方法的 效率.

Based on impulse response of modes in a uniform waveguide, a modal absorbing boundary condition, employed in finite difference-time-domain (FDTD) method, is specially calculated and investigated. The high order interpolated method is used to significantly improve the accuracy of modal absorbing boundary condition, and computing speed is accelerated by applying point matched method to identify the amplitude of modes. The numerical simulation shows that the number of nodes of FDTD can be dramatically reduced by applying the modal absorbing boundary condition that leads to the improvement of the efficiency of FDTD method.