主动式雷达导引头三通道集成接收前端设计

介绍了一种主动式雷达导引头三通道集成接收前端的设计方案及技术要点,全文围绕小型化设计思想,详细阐述了各主要关键部件Ku波段单刀单掷开关、低噪声放大器、镜像抑制混频器及单通道接收机等电路设计及测试结果,并最终实现了多功能部件的系统集成,整个集成接收前端具有低噪声、高增益、高隔离度、高镜像抑制及集成度高的特点,在主动式雷达导引头前端系统中具有较好的应用前景。     

Cu(Ⅰ) and Cu (Ⅱ) helical complexes formed with oligobipyridine ligand

A new asymmetric oligobipyridine ligand, 1-(5'-methyl-2, 2'-bipyridin-5-yl)-2-(6'-methyl-2, 2'-bipyridin-6-yl)ethane (L), in which the bipyridine units are bridged by CH_2CH_2 at 5, 6'-position has been synthesized. The ligand L reacts with Cu(Ⅰ) and Cu(Ⅱ) ions giving double-stranded helical complexes [Cu_2~ⅠL_2] (ClO_4)_2·Et_2O (1) and [Cu_2~ⅡL_2 (OH) (H_2O)][ClO_4]_3(2), respectively. Complexes 1 and 2 were characterized by X-ray diffraction analyses, ES-MS, ESR and cyclic voltammetry, etc. Differing from the oligobipyridine ligands bridged by CH_2CH_2 at 6,6'-or 5,5'-position, the ligand L not only forms a double-stranded helicate with Cu(Ⅰ) ion, but also gives a double-stranded helicate with Cu(Ⅱ) ion. The results show that the linkage mode of the spacer group to the bipyridine units exerts a great impact on the formation of helix.