再辐射边界条件在FDTD中的应用

Application of Re-radiating Boundary Condition in FDTD

目前的吸收边界条件存在编程复杂,占有内存空间与计算量过大等缺点。再辐射边界条件通过在截断边界处引入与入射波等效电磁流符号相反的源,使得穿过边界的电磁场得到有效的衰减。与传统的吸收边界条件相比,再辐射边界条件具有吸收性能优越,设计思路清晰,编程简单,内存占有少,计算时间短的优点。推导了在离散网格中再辐射边界的反射系数与时间及空间步长的关系,通过时域有限差分方法(FDTD)进行了验证,与理论值基本相符。

The absorbing boundary condition （ABC） in recent years is programmed difficultly. It needs many memory space and time when calculating. The re - radiating boundary condition （ rRBC ） introduces the current sources which are negative to the outgoing fields＇ equivalent currents at the boundary of the calculating domain. With the current sources, the outgoing fields are reduced obviously. Compared with other typical ABCs, rRBC is equipped with numerous advantages, such as clear thinking of design, easy programming, small memory occupation, high calculating efficiency.