【作者】 蒋新胜；

【导师】 廖斌；

【作者基本信息】 华东师范大学 ， 无线电物理， 2008， 硕士

【摘要】 随着移动通信以及无线多媒体业务的快速发展,UWB(Ultra-Wideband)无线技术越来越受到人们的重视。为了适应超宽带技术的发展,其关键射频器件超宽带滤波器不仅应用于定位、探测、武器制导等军事项目的微波电路,还可用于高速无线局域网等民用设备的微波电路,特别是超宽带微波滤波器的小型化问题也逐渐成为超宽带滤波器的研究热点。因此本课题的研究具有一定的研究和应用价值。本论文首先对超宽带滤波器的小型化技术在国内外研究现状进行了分析、总结和归纳,并对滤波器不同的超宽带实现方式进行了优缺点的比较。其次从具有阶跃阻抗结构SIR(stepped-impedance resonator)的微带传输线谐振器出发,对多模谐振器的结构和谐振条件进行研究,通过研究平行线耦合结构、叉指线耦合结构以及通过在接地面开孔的方法在较宽的频带范围内提高阻抗匹配,进行超宽带滤波器的设计,并分析各个参数对超宽带滤波器特性的影响。提出通过增加多模谐振器的阶数来增加低次谐振模以进一步增加超宽带滤波器的工作带宽的方法。本文还对在介质基板上沉积BST铁电材料薄膜进行了研究,利用BST铁电材料薄膜的介电非线性,改变外加的偏置电场,改变BST薄膜的介电常数,从而改变超宽带滤波器的工作通带。更多还原

【Abstract】 With the rapid development of mobile communication and wireless multimedia, people pay more attention to the UWB (Ultra-Wideband) technology. It is different from conventional wireless technology, because it is used in PAN of short distance. In order to be adapted to the broad uses of UWB technology, the UWB filter, regarded as one of the most important RF devices of a UWB communication system, should be applied not only to microwave circuits of military applications such as orientation, exploration, and so on, but also to the microwave circuits of civil applications such as using high speed WLAN. Therefore, research on UWB filters is becoming a hot spot.With development of MMIC, some microwave active circuits, such as amplifiers and modems, are getting smaller and smaller. However, many problems still exist in reducing sizes of microwave filters and oscillators. It is especially difficult to reduce the size of microwave filter of passive circuit. Therefore, researching and developing of miniaturized microwave filters with good performance are being pay much attention.In this paper, current research of miniaturized UWB filters inside and outside the country has been presented, analyzed at first. Different methods to design UWB filters have also been compared with each other. According to micro-strip transmission line resonators with SIR structures, the structures and resonance of multi-mode resonators are studied. It is found that impedance matching is improved in a wide frequency band with coupling structures of parallel and interdigital coupled lines by adding aperture to the ground plane. The UWB filter is designed with numerical simulation. It shows that experimental results have good agreement with theoretic results.According to nonlinear dielectric characteristics of BST film, a BST ferroelectric thin film in the substrate is deposited. The permittivity of the BST film changes along with change of the bias offset voltage, which causes the variety of bandwidth of UWB filter.更多还原