AI 中文总结
该研究提出基于 Yee 格式的二维 TM 模式 FDTD 求解器，用于线电流辐射建模，开放区域用 PML 截断。将其应用于三种非均匀配置并定量表征衍射情况，结果表明该框架能准确捕捉开放区域衍射及相关散射。
AI 中文摘要
本文提出了一种基于 Yee 格式的二维 TM 模式时域有限差分（FDTD）求解器，用于对沿 z 方向无限长的线电流辐射进行建模，开放区域用 Berenger 分裂场完全匹配层（PML）截断。在验证了自由空间中的柱面波传播和可忽略的晚期反射后，该求解器应用于三种非均匀配置：（i）通过具有单缝和双缝的单单元厚理想导电（PEC）薄片的衍射；（ii）来自圆形和矩形横截面的无限长 PEC 圆柱体的散射；（iii）来自具有不同横截面和介电常数的无限长介质圆柱体的散射。除了定性的场图外，对衍射情况进行了定量表征：通过运行离散傅里叶变换提取的稳态相量产生透射强度，据此计算条纹可见度和远场图案，并与封闭形式的夫琅禾费预测进行比较。单缝和双缝情况通过从接近零上升到接近 1 的可见度清晰区分，双缝干涉最大值与光栅条件 arcsin(m \lambda_0 / d) 的偏差在不到一度的范围内。对于介质圆柱体，可以预期场以减小的内部波长 \lambda_0 / \sqrt{\epsilon_r} 穿透障碍物，并且散射场强度随介电常数对比度增加。一种参考减法方法始终分离出散射场。结果证实 FDTD - PML 框架准确地捕捉了开放区域的衍射以及与几何形状和材料相关的散射。
英文摘要
This paper presents a two-dimensional TMz finite-difference time-domain (FDTD) solver based on Yee's scheme for modeling radiation from an infinitely long z-directed line current, with the open region truncated by a Berenger split-field perfectly matched layer (PML). After validating cylindrical-wave propagation and negligible late-time reflections in free space, the solver is applied to three inhomogeneous configurations: (i) diffraction through a one-cell-thick perfectly electrically conducting (PEC) sheet with single and double slits; (ii) scattering from infinitely long PEC cylinders of circular and rectangular cross section; and (iii) scattering from infinitely long dielectric cylinders of varying cross section and permittivity. Beyond qualitative field maps, the diffraction case is characterized quantitatively: a steady-state phasor extracted by a running discrete Fourier transform yields the transmitted intensity, from which the fringe visibility and the far-field pattern are computed and compared against the closed-form Fraunhofer prediction. The single- and double-slit cases are cleanly separated by a visibility that rises from near zero to near unity, and the double-slit interference maxima agree with the grating condition arcsin(m λ_0 / d) to within a fraction of a degree. For dielectric cylinders, the field penetrates the obstacle with the expected reduced internal wavelength λ_0 / \sqrt{ε_r}, and the scattered field strength grows with permittivity contrast. A reference-subtraction method isolates the scattered field throughout. The results confirm that the FDTD-PML framework accurately captures open-region diffraction and geometry- and material-dependent scattering.
CommentsAs part of the computational electromagnetics project. 10 pages, 10 figures, 22 citations
