复杂目标对柱面波散射的二维ADI-FDTD方法

2D ADI-FDTD method applied to EM scattering with cylindrical wave source illumination

为了处理柱面波照射复杂目标的散射问题,给出了二维ADI FDTD方法中加入柱面波(线源)的详细计算公式.这种加源方式的特点是两个子时间步上都存在线电流源的激励.作为验证,应用文中方法计算了线电流照射金属圆柱的辐射方向图,与级数解结果一致,给出了线电流照射复杂目标二维机翼的辐射方向图,与常规FDTD计算结果吻合得很好,表明此种方法的正确性,计算中时间步的取值突破了Courant稳定性条件的限制.

To analyze the scattering with cylindrical wave illumination, a line source excitation method in the 2D ADI-FDTD method is discussed. The source excitation is imposed to both the first and the second subiterations simultaneously, rather than forced in the first subiteration only. In order to verify the proposed scheme the scattering problem of a conducting cylinder illuminated by a line current source is treated. The ADI-FDTD result is in good agreement with the closed form solution. Also, the scattering of a 2D airfoil model is computed, showing the practical applicability of the presented scheme. The time-step size in ADI-FDTD is no longer restricted by the Courant condition. If the cell size discretized in space is smaller, the 2D ADI-FDTD method is more efficient than the conventional FDTD method.