【作者】 宋超；

【导师】 于军；

【作者基本信息】 华中科技大学 ， 半导体芯片系统设计与工艺， 2007， 硕士

【摘要】 高精度低损耗薄膜移相器不仅可以显著改善相控阵雷达系统的性能,而且能大大降低系统成本。钛酸锶钡(BST)薄膜因其具有高的介电调谐量、相对低的损耗和快的开关速度,在微波移相器制备中具有明显优势。在分析研究目前常用的几种薄膜介质移相器结构与特性的基础上,本文选用分布式电容负载型BST薄膜移相器结构为研究对象。电容负载型BST薄膜移相器由高阻传输线和周期性负载的钛酸锶钡薄膜电容构成,其中的高阻传输线为共面波导。通过对共面波导BST薄膜移相器的理论分析并结合自身工艺条件和生产成本,本文选择负载电容为叉指电容结构,用电磁仿真软件Agilent ADS 2005A对叉指电容结构参数进行模拟,分别考察叉指电容的各个结构参数对移相单元反射系数、插入损耗和移相度的影响,选择综合性能最优的参数。然后在传统的叉指结构的基础上,对其进行改进,用ADS软件设计出移相器版图,并对移相器整体性能用计算机模拟,得了较好的结果,其反射系数低于-9dB,插入损耗小于0.9dB,相移接近330o。更多还原

【Abstract】 The wide application and rapid development of phased array radar make phase shifter become the focus of research, which is the key component of phased array radar. Low loss and low cost microwave phase shifters are required to improve performance and reduce the cost of phase array. BaSrTiO3 (BST) thin films have great predominance in microwave phase shifter circuit applications because of their high tunable, relatively low loss, and fast switching speed.After the analysis of some structures commonly used in dielectric phase shifter, a structure named distributed capacitor-loaded phase shifter was carried out. It is comprised of a high-impedance transmission line periodically loaded with BST thin film capacitors, which is called coplanar wave-guide (CPW). After the analysis of CPW BST thin film phase shifter, the fabrication technology and the cost, the interdigital capacitor was used as the loaded capacitor. Based on the model, the parameters was simulated in Agilent ADS 2005A, and then its structure parameter in influencing the reflectance, insert loss and the phase shift of the phase shifter were considered, and an optimized parameter of the structure was chosen. Finally the structure parameters of interdigital capacitors were improved, based on the traditional one, and the layout was designed using ADS. The whole performances of this phase shifter were simulated by computer, and acquired a better result. The reflectance is lower than -9dB, the insert loss is lower than 0.9dB, and the phase shift is nearly 330o.更多还原