中文说明：当雷达工作于高频区、物体的尺寸远大于电磁波长时，电磁波与物体的相互作用就表现出“局部”特性，与物体的形状密切相关。
English Description：
When the radar works in the high frequency region and the size of the object is much larger than the electromagnetic wavelength, the interaction between the electromagnetic wave and the object shows "local" characteristics, which is closely related to the shape of the object.