结构电磁有限元分析的网格依赖性研究

Study of mesh-dependency in finite element analysis of structural electromagnetic performance

分析了基于有限元方法的超材料电磁性能仿真分析结果对有限元网格的依赖性。通过对仿真结果的分析,发现基于S参数的材料性能参数反演结果对S参数的计算准确度的依赖性巨大,特别是处在谐振频域的S参数误差会导致等效电磁参数的性态误差。针对基于求解频率的网格自适应技术对远离求解频率的谐振频域的分析结果的准确度改善不够这个问题,需要确定合适的求解频率来执行网格自适应。提出了一种改进电磁性能仿真分析准确度的方法,其基本思想是首先给定一个初始的求解频率值,根据Kramers-Kronig关系反演等效电磁参数,进而获得谐振频率的近似值,并把此值作为求解频率来实现网格自适应以获得合适的网格剖分,最后经扫频获得S参数并进行等效电磁参数的反演。数值结果表明,该方法可有效提高仿真分析和参数反演的准确度。

Mesh-dependency in simulation results of metamaterial electromagnetic performance was analyzed based on finite element analysis. It is found in the simulation results that the retrieval metamaterial equivalent performance parameters based on S-parameters have a strong dependence on the S-parameters＇ calculation accuracy, especially in the resonant frequency-domain where S-parameters＇ error may cause a qualitative error of the electromagnetic parameters. To improve the accuracy when a solution frequency is away from the resonant frequency based on the mesh-adaptive technology,a proper solution frequency needs to be determined for implementing the adaptive mesh of high quality. So a new method was proposed to improve the accuracy of the electromagnetic simulation analysis. In the new method, firstly the electromagnetic parameters could be retrieved from the S-parameters through the Kramers-Kronig relationship with an initial solution frequency,and thus an approximate value of the res- onant frequency could be obtained. Afterwards, the adaptive mesh of high quality was achieved, using the approximate value as the solution frequency. Finally the electromagnetic parameters of high accuracy were retrieved from the S-parameters through the frequency-sweep technology. Numerical results show that the new method can effectively improve the accuracy of the simulation analysis and parameters-retrieval methods.