频率选择表面电磁特性计算的时域有限差分和外推混合法

Electromagnetic Characteristics Calculation of FSS by the Mixed Method Combining FDTD and Extrapolation Method

目前,频率选择表面(Frequency Selection Surface,FSS)作为一种空间滤波器,在军事领域得到广泛应用,因此对其电磁特性的研究具有重要意义。结合时域有限差分(Finite Difference Time Domain,FDTD)法和外推法各自的优点,采用FDTD法和外推法相结合的混合算法来计算周期性结构FSS的反射系数。通过引入Floquet定理且综合考虑FSS的周期边界、吸收边界等条件,建立三维计算模型,并对其进行计算。结果表明,在相同精度条件下,该混合法相对仿真软件显著提高了计算速度且减少了占用计算机内存,可为后续FSS的电磁特性研究提供重要的参考依据。

The frequency selection surface(FSS)is currently used as a kind of spatial filter,which is widely used in the military fields,so it is of great significance to study its electromagnetic characteristics.Combining the advantages of finite difference time domain(FDTD)method and the extrapolation method,a hybrid algorithm combining the FDTD method and the extrapolation method is used to calculate the reflection coefficients of the FSS.By introducing the Floquet theorem and comprehensively considering the periodic boundary,absorption boundary of the FSS,a 3-D model is established.The calculation results show that,under the same accuracy conditions,the hybrid method greatly improves the calculation speed and reduces the occupation of computer memory compared with the simulation software.It can provide an important reference for the subsequent study of the electromagnetic characteristics of the periodic structure frequency selection surface.