【作者】 吴伟；

【导师】 崔铁军； 孙忠良；

【作者基本信息】 东南大学 ， 电磁场与微波技术， 2017， 硕士

【摘要】 电磁超材料相对于自然界已有的传统材料而言,是由一系列亚波长结构单元按照人工设计进行周期或非周期排列的结构,可以获得传统材料所不具备的电磁性能,实现对电磁波更有效的调控。电磁超材料从提出到现在经历了从三维结构到二维平面,再到数字化可编程的快速发展。但是,电磁超材料由于大量单元的周期或非周期排列,其整体结构的电尺寸很大,因此就对计算机性能和运算时间提出很高的要求,很大程度上制约了复杂设计的研发效率。而阵列综合理论及技术专注于结构的远场辐射方向图而忽略了近场等其他电磁特性,在保证计算结果准确性的同时可以大幅提高计算速度,并且对计算机性能也没有特别要求。本论文利用阵列综合理论及技术设计了一系列在传统仿真工具下难以完成的电磁超表面,主要研究内容包括如下几个方面:1)在MATLAB中编写阵列综合技术程序,对电磁超表面的辐射特性进行分析,得出方向图的大致形状、主瓣方向、波束宽度以及主瓣内的旁瓣等。2)使用阵列综合技术设计并优化一个X波段的双功能全息宽带反射阵,当两个喇叭天线在两正交平面内照射时,口径面可以产生两个笔锥波束。3)设计了一个等增益波束扫描反射阵,利用天线阵列法分析速度快的优势,计算并优化馈源位置,使得反射阵口径面上产生的笔锥波束可以从17度扫描至40度,同时保持增益相等。4)使用阵列综合技术设计了一个工作频段为60GHz的超电大尺寸的毫米波各向异性传输式编码超表面。在x方向极化的激励下,采用全息的思想进行编码,在平面内产生两个尖波束,两波束的方向可由编码方式自由调控;在y方向极化的激励下,运用编码电磁超表面的卷积性质,在大角度(51.6度)方向产生笔锥波束。更多还原

【Abstract】 Metamaterials,compared to traditional materials existing in nature,are consist of a series of sub-wave units,by which the array are well arranged to control the electromagnetic wave.From the beginning till now,metamaterials have developed from three dimension structures to two dimension surfaces,and further,to digital and programmable metasurfaces.Meanwhile,owing to the large number of units,the size of metasurface is usually electrical large,which would cause large simulation time and high demands on computer performances,and this restricts the efficiency of complex designs.Antenna-array theory only concentrates on radiation performance rather than near fields and other electrical characteristics,and this makes it not only produce believable outcomes,but also reduce the computational time and demands on computer hardwares.Here,the antenna-array theory is used as the analysis tool to design several metasurfaces,which are hard to analysis under traditional simulation softwares.The main contents of the thesis are as follows:1.Realized the antenna-array theory in MATLAB environment,which can analyze the radiation performance of metasurfaces,and obtain the general pattern shape,mainbeam direction,beam width,and sidelobes in the mainbeam area.2.Designed and optimized an X-band dual-functional broadband holographic reflectarray using antenna-array theory.When two horns illuminate in two orthogonal planes,the aperture could produce two pencil beams.3.Designed an equal-gain scanning reflectarray using the antenna-array theory,which can optimize the feed position and make the aperture produce equal-gain pencil beam scanning from 17 degree to 40 degree.4.Designed a 60GHz electrical ultra-large anisotropic transmitting coding metasurface using antenna-array theory.Under the x-polarization excitation,the aperture could generate two independently controllable pencil beams using the concept of holography in coding series;meanwhile,under the y-polarization excitation,the coding metasurface could produce a pencil beam in a large deflection angle(51.6 degree),owing to the convolution characteristic.更多还原