基于CFS-PML的高阶有限元在地质雷达数值模拟中的应用研究

In the numerical simulation of ground penetrating radar (GPR), to attenuate the evanescent wave generated by the thickness of the truncated area or the influence of parameters, a new method is proposed to use the complex frequency shifted perfectly matched layer (CFS-PML) as the absorption boundary and combined with the higher-order finite element method (HO-FEM) in the frequency domain to solve the distribution of the total electromagnetic field components. The method improves the properties of the dielectric intrinsic tensor matrix in the truncated domain and uses the matrix frequency shift parameter α to absorb the evanescent wave and improve the absorption performance at the grazing angle. Numerical experiments are conducted on the method. Compared with the traditional PML, the accuracy of the HO-FEM method combined with CFS-PML is significantly improved, the reflection error is reduced by 10?30 dB extra, and the calculation time is saved by 17%?30%. In addition, the method can be applied to the calculation of the total electromagnetic field of a complex geological structure model, which provides a new method for the numerical simulation of geological lidars.     

基于HIE-FDTD方法的太赫兹频段石墨烯吸收器的设计

应用混合显隐式时域有限差分(hybrid implicit-explicit finite-difference time-domain, HIE-FDTD)方法对石墨烯吸收器进行数值模拟. 通过辅助差分方程（auxiliary difference equation, ADE）将石墨烯带内电导率引入到HIE-FDTD方法中并结合共形技术对设计的新型石墨烯吸收器完成了特性分析. 数值结果表明:该吸收器在2.68 THz附近吸收率可达到99.8%,而且在太赫兹频段下可以通过控制石墨烯的化学势和圆环宽度调整该吸收器的工作频率. 本文设计的环状结构吸收器结构简单,在检测器、传感器、滤波器等太赫兹器件方面具有潜在的应用.