随着图像识别技术的不断发展,人脸识别系统对虹膜识别滤光片的要求不断提高,光在大角度入射时,光谱偏移量往往较大而导致识别失败,因此急需一种低角度效应良好的带通滤光片。利用光谱拆分原理设计了一种大角度、小偏移量的带通滤光片。通过调节氢气流量使得Si-H在增大折射率的同时仍能保持较低的吸收率,从而改善虹膜识别滤光片的角度效应。基于对薄膜材料沉积工艺的研究,采用一种特殊的膜系结构,解决了因薄膜内部结构疏松而发生的脱膜问题。测试结果表明,该膜系结构能满足虹膜识别滤光片的各项技术要求。

为了研究超高速碰撞产生闪光辐射的速度及角度效应,利用建立的瞬态光纤高温计测量系统结合二级轻气炮加载系统,进行了6种实验条件下的超高速碰撞实验。每组实验使用一组光纤探头,基于实验所获原始数据结合标定,通过Matlab编程处理得到了给定实验条件及光纤探头安装条件下,超高速碰撞LY12铝靶产生的闪光辐射与碰撞速度和弹丸入射角度的关系。实验结果表明,超高速碰撞LY12铝靶产生的闪光辐射在温度峰值出现前近似与碰撞速度和弹丸入射角度(弹道与靶板平面的夹角)正弦乘积的平方成正比；碰撞闪光辐射在温度峰值出现后近似与碰撞速度和弹丸入射角度正弦乘积的0.75次幂成正比,与理论推导结果基本吻合。

In order to realize wideband filtering properties of frequency selective surface (FSS), FSS of closely packed elements is presented. The Y loop elements are chosen as the graphics elements. Based on the spectral domain method, the frequency response is analyzed for different incident angles and polarizations. The result of the numerical analysis shows that the dense FSS has wide passband with better independence of angle and polarization.

Two frequency selective surface (FSS) configurations with flat topped passband are presented in this paper. One configuration is single layer FSS with lambda/4 thickness dielectric loaded on both sides, and the other is double layers FSS. Based on the modal matching method, the frequency response properties including angle effect and polarization effect of both FSS configurations are analyzed, and the plots of the frequency versus transmission coefficient are obtained for different incident angles and polarizations. It is shown that the structure with the single layer FSS embedded centrally in the lambda/2 thickness dielectric has a wider flat top bandwidth of 6.8 GHz than that of the double layers FSS of 3 GHz. In addition, the fabrication of single layer is relatively easier than the double layers FSS.

本文回顾智能窗的薄膜技术和光谱选择性的薄膜、角度选择性的薄膜、电致变透射膜系的结构以及热致变透射薄膜的研制情况。