等效环路有限差分算法及其在人工复合材料设计中的应用

本文实现了一种新颖的等效环路有限差分算法, 这种算法借鉴传输线算法的思想, 在Yee氏网格中引入等效集总元件, 包括常规介质中的等效串联电感、并联电容和左手材料中的等效并联电感、串联电容等. 良好的物理思想使其可以提供适用色散介质计算的收敛性条件, 更加适合仿真计算频率选择表面和超材料等色散介质. 为了提高其计算效率, 研究了核内加速技术, 这种技术理论上可达到最高4倍的加速, 实际应用中得到2倍左右的加速效果. 使用该算法进行了超材料吸波体结构的设计, 通过单双环电阻加载实现宽带电磁波吸收功能. 隐身天线罩对于实现天线的带外隐身有着重要作用, 利用该算法设计了工作频率为1 GHz, 隐身频带在3 GHz到9 GHz的天线罩. 并与两个加工样品的测量结果进行了比较, 对比的结果验证了算法的正确性. 同时核内加速技术的有效性也通过仿真时间比较得到了验证. 关键词： 等效环路有限差分算法 核内加速 超材料吸波体 隐身天线罩

An algorithm of equivalent curcuit of FDTD and its application to designing metamaterial structure

A novel finite-difference time domain (FDTD) algorithm named equivalent circuit FDTD (EC-FDTD) is realized, which introduces lumped elements from transmission line theory into Yee cell. It includes lumped elements such as series inductance and shunt capacitance in the right-handed materials, as well as shunt inductance and series capacitance in the left-handed materials. Due to its promising physical thoughts, it can be easily generalized to arbitrary dispersive materials including frequency selective surfaces and metamaterials. The technology of streaming single-instruction multiple-data (SIMD) extensions (SSE) was proposed by Intel and is currently utilized in personal computers. SSE is a kind of parallel speedup technology in one core. The speedup can be achieved four times in principle without changing hardware. Combined with SSE, the EC-FDTD can be apparently accelerated. Twice speedup is achieved in the tests of this paper. The algorithm of EC-FDTD is utilized to design the wideband metamaterials absorbers by employing the single square and double square loops loaded with the lumped resistors. The invisible radome has a great impact on reducing the radar cross section of the antenna out of band. The radome is designed with operating frequency to be 1 GHz and the absent bandwidth from 3 GHz to 9 GHz by the algorithm. And then these prototypes are fabricated and measured. From the comparative results, the correctness of EC-FDTD and the speedup of the SSE are both verified.
Keywords： EC-FDTD SSE metamaterial absorbers invisible radome