基于液晶调谐的太赫兹超材料滤波器研究

发布时间：2018-06-28 20:39

本文选题：太赫兹 + 液晶　；参考：《哈尔滨理工大学》2017年硕士论文

【摘要】：超材料,曾被美国《科学》杂志评为过去十年人类最重大的十项科技突破之一。随着信息技术的高速发展,超材料逐渐进入应用层面。由于超材料的超常电磁特性主要由人工设计的周期性结构单元的形状和物理尺寸决定,一旦结构参数确定,其表现出的电磁性质被局限住。所以,研究者们越来越关注可调谐超材料研究。液晶由于其介电常数可以通过外加电压进行控制,因而非常适合用来调谐太赫兹超材料的电磁特性。基于上述原因,本文提出两种基于液晶调谐的太赫兹超材料滤波器。基于液晶调谐的太赫兹超材料窄带滤波器,其结构单元由周期性金属圆环深槽结构组成,并且将液晶注入深槽结构中用以实现调谐功能。使用基于有限元方法的仿真软件对滤波器结构单元的内外半径,金属厚度等参数进行优化,得到性能较好的窄带滤波器。通过TE波、TM波和对入射电磁波角度的改变,证实滤波器可实现广角入射工作,不受入射波偏振状态影响,在深槽结构中注入DFLC液晶和LC1825液晶,比较两种液晶材料对滤波器的频率选择范围和相位变化的影响。基于液晶调谐的太赫兹宽带阻超材料滤波器,该结构是一种相同结构但不同比例尺寸闭合方形金属谐振环结构的多层超材料叠加而成,并且在两石英衬底间填充液晶用以实现调谐功能。使用基于有限元方法的仿真软件对该滤波器结构的闭合方形金属谐振环的大小、线宽、结构厚度等参数进行优化,得到性能较好的宽带阻滤波器,并对滤波器工作时的表面电流和磁场进行分析。探究入射波的偏振状态和入射角度对该太赫兹超材料滤波器的性能影响,分析所提出的宽带滤波器的性能:该超材料宽带滤波器频率选择范围达到了563.2GHz,带阻内的带内抑制达到了95%以上,并且带阻的上升沿和下降沿的陡峭度分别为1000%/THz,857%/THz。
[Abstract]:Metamaterials has been named one of the ten most important technological breakthroughs in the past ten years by American Science magazine. With the rapid development of information technology, metamaterials have gradually entered the application level. Because the supernormal electromagnetic properties of the supermaterials are mainly determined by the shape and physical size of the periodically designed structural units, once the structural parameters are determined, the electromagnetic properties of the supermaterials are limited. Therefore, researchers are paying more and more attention to the study of tunable metamaterials. Because the dielectric constant of liquid crystal can be controlled by applied voltage, it is very suitable for tuning the electromagnetic properties of terahertz supermaterials. For the above reasons, two terahertz metamaterial filters based on liquid crystal tuning are proposed. The tunable terahertz narrow band filter based on liquid crystal tuning is composed of periodic metal ring deep groove structure and the liquid crystal is injected into the deep groove structure to realize the tuning function. The parameters of the inner and outer radius and metal thickness of the structural element of the filter are optimized by using the simulation software based on the finite element method, and a narrow band filter with better performance is obtained. By means of te wave TM wave and the change of incident electromagnetic wave angle, it is proved that the filter can realize wide-angle incident operation without the influence of polarization state of incident wave. DFLC liquid crystal and LC1825 liquid crystal are injected into deep groove structure. The effects of two kinds of liquid crystal materials on the frequency selection range and phase change of the filter are compared. Based on the liquid crystal tunable terahertz wideband resistive material filter, the structure is a superposition of multilayer supermaterials with the same structure but different proportions of the closed square metal resonant ring structure. Liquid crystals are filled between two quartz substrates to achieve tuning. The size, linewidth and thickness of the closed square metal resonant ring of the filter structure are optimized by using the simulation software based on the finite element method, and the wideband resistive filter with better performance is obtained. The surface current and magnetic field of the filter are analyzed. The effects of polarization state and incident angle of incident wave on the performance of the terahertz supermaterial filter are investigated. The performance of the proposed wideband filter is analyzed: the frequency selection range of the UWB filter is 563.2 GHz, the in-band suppression in the band stop is more than 95%, and the rise edge and the descent edge of the band stop are respectively 1000 / THz-857 / THZ / THZ.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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