基于TF/SF方法的三维复合目标电磁散射FDFD研究

分析三维频域有限差分(FDFD)中通过总场-散射场(TF/SF)边界引入入射波的方法.基于等效原理,在TF/SF边界处设置等效面电磁流,将入射波引入总场区.根据边界附近节点的位置特点,将方程式中的相关节点加入或扣除入射波的相应分量修正FDFD方程式,使得方程式中的各节点满足同为总场或同为散射场的条件.算例结果验证了该方法的正确性.利用FDFD方法计算涂敷吸波材料的复合von Karman型弹头和某导弹模型的双站RCS(radar cross section),数值结果说明该方法是分析复合目标电磁散射问题的一种有效方法.

3D FDFD Algorithm with TF/SF Technique for Electromagnetic Scattering from a Composite Target

A total-field/scattered-field(TF/SF) technique is used to introduce an incident wave for a scattering problem in three-dimensional finite-difference frequency-domain(FDFD) method.According to the equivalence principle,an incident wave is introduced in total-field region by setting equivalent electromagnetic currents on TF/SF boundary.FDFD equations at nodes near TF/SF boundary are modified to satisfy conditions that all nodes involved belong either to total-field or to scattered-field.Numerical results validate this technique.The presented technique is mainly applied to scattering problem with a composite target,which is composed of perfectly electronic conductor(PEC) and lossy dielectric medium.Bistatic radar cross section(RCS) of a composite von Karman missile warhead and a missile model are computed with FDFD method.The results demonstrate its applicability in analyzing electromagnetic scattering with composite targets.