【作者】 韩卫敏；

【导师】 戴显英；

【作者基本信息】 西安电子科技大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 随着航空、航天技术的发展以及军事应用的需要,移相速度快、移相精度高、插入损耗小、功率容量大、体积小、重量轻、成本低、可靠性高的相控阵雷达移相器已成为各军事大国竞相研发的热点与重点。钛酸锶钡（barium strontium titanate,BST）铁电薄膜以其室温下的高介电常数、高调谐性和低介电损耗等优点而被认为是制作新型高性能、低成本相控阵雷达铁电移相器的最佳选择。本论文研究了在毫米波有源相控阵雷达的T/R组件中有重要应用前景的铁电薄膜介质移相器,分析了移相器结构对铁电薄膜的性能要求。对钛酸锶钡( Ba_x Sr_1-x TiO)3,BST)薄膜材料的结构、性能及制备工艺进行研究,并采用溶胶-凝胶法制备了致密均匀的BST薄膜。在对现有的几种薄膜介质移相器结构进行分析的基础上,根据微波平面传输线理论设计了一种共面波导型BST铁电薄膜移相器,其结构是在MgO衬底上生长一层BST薄膜,再在BST薄膜上面制作接地板和中心信号线。根据共面波导型BST铁电薄膜移相器的结构与性能特点,对现有的高频电磁仿真软件进行了分析、对比研究。根据研究分析结果,采用ANSOFT HFSS和ANSOFT DESIGNER对所设计的共面波导型BST铁电薄膜移相器进行了结构与性能的综合模拟分析。根据模拟分析结果,对共面波导型BST铁电薄膜移相器结构进行优化,并研究了移相器结构参数及BST薄膜介电性能参数对共面波导型BST铁电薄膜移相器性能影响的规律。最后绘制了移相器的版图。本论文研究结果表明:设计的BST共面波导移相器的模拟优值为53.56°/dB;共面波导的中心信号线宽与缝隙宽度对移相器的插入损耗有重要影响,增加信号线或缝隙的宽度都会降低移相器的插入损耗,但同时又会使移相度减小;增加BST薄膜的厚度可以提高移相度,但损耗也随着增加了:BST薄膜的介电性能是影响移相器性能的重要因素,适当降低BST薄膜的介电常数,减小损耗正切角tgδ,提高介电协调率是提高移相器性能的主要途径;金属电极引起的损耗是移相器损耗的主要部分,采用高电导率的金属可以减小移相器的插入损耗。更多还原

【Abstract】 With the development of aviation and space technology and the needs of the military, the phase array’s radar has developed quickly. It is urgent to develop a phase shifter which has high speed and precision of phase shift, low insert loss, large capacity of power, small bulk, little weight, low cost, high reliability. Ferroelectric phase shifter can meet these requirements well and has attracted more and more focus. BST Ferroelectric films, which have many merits such as high Dielectric constants, high tunability and low loss, are considered as the optimum choice to prepare ferroelectric phase shifters.In this thesis, millimeter-wave thin film dielectric phase shifter was investigated, which has significantly potential application in T/R module of phased array radar. The requirements to the properties of Ferroelectric thin film applied to dielectric phase shifter were analyzed. The property ,structure and preparing technique of BST thin film were investigated .Ba_xSr_1-xTiO₃ （BST） film is prepared used Sol-gel technique. The film is smooth, has no cracks and of good properties. After the analysis of some structures commonly used in dielectric phase shifters, according to the theory of microwave planar transmission lines, A CPW-type ferroelectric thin film dielectric phase shifter was designed, The phase shifter was a coplanar waveguide （CPW） transmission line with two substrates of BST/MgO structure. Considering characteristic of the device, the phase shifter was simulated with the high frequency structure simulator （HFSS）, which is commercial software based on finite element method. We study the rule how the structure parameters affect the insert loss and phase shift of the device and how the dielectric properties of BST thin films do. These parameters were optimized to improve the performance of the phase shifter.Finally the layout of the BST thin film phase shifter was designed.The results show: the phase shifter had a figure of merit （FOM） of 53.56°/dB. Structure parameters of the CPW have great influence on the performance of the phase shifter. Widening the signal line width of the CPW line can reduces the insert loss of the phase shifter, but reduces the phase shift also. It is similar to the gap width of the CPW. Ticker BST film can obtain larger phase shift, but the insert loss is higher too. The dielectric properties of BST thin films are also important factors which affect the performance of the phase shifter. To obtain good performance, lower Dielectric constants （usually less than 500） and lower loss tangent is expected. The higher the更多还原