提出了一种由表层矩形金属周期图案、聚酰亚胺薄膜基底和金属反射面组成的新型反射型极化变换器。为了降低极化变换器对基底厚度的敏感度, 增大工作带宽, 该设计采用将传统反射型极化变换器表层金属线栅开口截断和增大金属线栅宽度的方法, 引进了表层金属图案对两正交极化方向电磁场的等效电容电感效应, 进行相位调制。仿真结果表明中心频率为 500 GHz时, 工作带宽可达到 140 GHz, 插入损耗小于0.5 dB, 并且在一定基底厚度条件下误差在一定范围内, 整体性能几乎无变化。仿真表明该极化变换器有效增大了工作带宽, 并降低了对基底厚度敏感度。提出了薄膜光刻工艺来对设计的极化变换器进行加工制作。

A reflective polarization converter constructed by a layer of rectangle metal pattern, an ultrathin polyimide substrate, and a layer of metal reflector are introduced. To lower the sensitivity to the thickness of the substrate and increase the working bandwidth, the method of broadening and truncating the metallic wire grid of traditional polarization converter is proposed, which introduces the equivalent capacity and the equivalent inductance of two orthogonal linearly polarized incident electromagnetic waves, so the phases are modulated separately. The simulation result suggests that at 500 GHz, the working bandwidth is about 140 GHz, the insert loss is less than 0.5 dB; and while the thickness error of the polyimide substrate is within a due range, the performance of the polarization converter would keep stable. The designed converter efficiently lowers the sensitivity to the thickness of the substrate and increases the working bandwidth, besides, a flexible thin-film photoetching method is proposed for the process of the polarization converter.