基于物理光学假设的导体表面电流密度误差分析

用物理光学法计算理想导体雷达散射截面过程中,需要基于无限大切平面假设计算表面电流密度.只有对表面比较光滑的电大尺寸目标,该假设才近似满足,而在一般情况下由该方法求得的表面电流密度存在误差.将二维导体圆柱、方柱以及三角柱等构型在不同入射频率、极化下的物理光学表面电流密度与精确解或矩量法结果进行了对比.分析表明:横磁波照射时物理光学法除在顶点处有较大误差外,基本能够正确反映出表面电流密度分布情况.横电波情形下物理光学法难以如实反映照射面和阴影面电流的谐振变化,与入射方向平行的面上表面电流密度也有较大误差.

Error analysis of surface current density on perfect electric conductor based on physical optics

In radar cross section (RCS) calculation of perfect electric conductor (PEC) targets using physical optics (PO), the surface current was calculated based on the assumption of infinite tangent plane. The assumption was fulfilled only for the electric-big and smooth-surface targets, while there is error induced by PO in general situation. The PO's surface current of two-dimensional profiles such as cylinder, square prism and triangular prism was calculated and compared with accurate or method of moments (MoM) result. The analysis shows that when transverse magnetic (TM) wave is incident on the target, PO reflects the true situation except for some vertices. However, when transverse electric (TE) wave is incident on the target, PO cannot show the resonant oscillation in illuminated and shadowed surfaces and there are still big errors in the surface current parallel to the incident direction.