电磁波在光栅表面上反射和衍射的理论研究

本文从严格的场匹配方法出发,对电磁波在矩形截面光栅上的反射和衍射进行了理论研究。对这种光栅作为频率扫描天线的计算显示出,不论满足或不满足布喇格条件,在较宽的角度范围内入射,经调节槽宽和槽深都可获得理想的耀射。对于不满足布喇格条件,在两个互易角中较大的一个入射时,-1次衍射波有较高的效率和较宽的频带。而对这种光栅作为奥罗管中反射镜的特性的理论计算指出,它具有极宽的频带。同时本文还给出了不同频率平面波垂直入射时的等效光栅位置,以及电磁波在光栅表面反射时所引起的相位改变。

THEORETICAL STUDIES OF REFLECTION AND DIFFRACTION OF EM WAVE BY GRATING

The electromagnetic field problem of a rectangular grating illuminated with TM wave is studied theoretically by means of rigorous field-matching and moment method. The numerical calculations show that the grating, as a frequency scan antenna, can produce perfect blazing in a wide range of incident angle only through adjusting the size of width and depth of the groove no matter Bragg condition is satisfied or not. Higher efficiency and broader frequency band of - 1 order diffraction wave can be achieved only at the larger reciprocal incident angle. And very broad frequcncy band can be expected when the grating is employed as a reflecting mirror in an orotron. The effective grating position and phase change of reflection wave by grating are also numerically presented.