【作者】 王瑞；

【导师】 王高峰；

【作者基本信息】 武汉大学 ， 微电子学与固体电子学， 2010， 博士

【摘要】 左手材料是一种新型的人工电磁功能材料,它所具有的多种独特电磁特性使其在很多方面得到应用。本文讨论了左手材料在天线的定向辐射以及隐身衣结构方面的应用,推导出左手材料物理尺寸与其工作频率之间的关系,提出左手材料等效电路模型各元件参数以及组成左手材料的细导线棒和缺陷环尺寸参数计算的方法,设计出应用于手机频率的左手材料天线覆盖层,使天线实现定向辐射。由于左手材料的制备过程比较复杂,需要首先利用电磁仿真算法对其进行仿真计算,对其电磁特性进行理论预测,因此本文利用时域有限差分算法对左手材料进行三维全波电磁仿真,推导出各向异性介质中的时域有限差分算法的差分表达式,并仿真验证三维隐身衣结构的电磁隐身效果。由于左手材料是一种色散介质,而且其几何结构非常复杂,因此在利用时域有限差分算法对其进行仿真时,需要消耗大量的计算时间,为了在保证计算精度的前提下提高全波电磁仿真的效率,本文提出了针对色散介质的分段线性递归卷积弱条件稳定时域有限差分方法,该算法能够在节省大量的计算机资源的同时满足高精度的要求。利用分段线性递归卷积弱条件稳定时域有限差分方法,本文又对微带天线衬底的色散特性进行了研究,对微带天线的衬底分别进行色散以及非色散两种形式的建模,分析衬底色散对天线性能的影响,讨论得出色散衬底模型下的回波损耗以及输入阻抗都比非色散模型的低,这对高频天线的设计具有指导作用。总之,本文主要是利用时域有限差分算法对左手材料的电磁特性进行仿真,并在此过程中提出了适用于色散介质的高效精确的分段线性递归卷积弱条件稳定时域有限差分算法,具有一定的理论和实际意义。更多还原

【Abstract】 Left-Handed materials is a new kind of artificial electromagnetic materials, it has a variety of unique electrical and magnetic properties to be applied in many areas, this paper discusses the left-handed materials in the directional radiation, and the application of metamaterial cloak. We conclude the relationship between the physical dimensions and the operating frequency in the design of Left-Handed materials, then study the calculation method of L, C parameter of Left-Handed materials equivalent circuit model, and design a left-handed materials cover which is suitable for mobile phone antenna, so that the antenna can achieve directional radiation.As the preparation process of Left-Handed materials is relatively complex, and generally we use the electromagnetic simulation algorithm firstly to get the theoretical prediction of its electromagnetic properties, so we use Finite Difference Time Domain algorithm to get the full-wave electromagnetic simulation result. In this paper, we get the differential expression in the anisotropy media and simulate the three-dimensional metamaterial cloak.Because the Left-Handed materials is a type of dispersive media, and its geometry is very complex, so when we need a lot of computing time and resource, in order to get the high accuracy and save the computational resource, we propose the Piecewise Linear Recursive Convolution Weakly Conditional Stability algorithm which can save a lot of computer resources while meeting the required precision.Using the Piecewise Linear Recursive-Convolution Weakly Conditional Stability algorithm, we study the effect of dispersive substrate of microstrip antenna, then discuss the difference of return loss and input impendence between dispersive and nondispersive substrate model, and we find that the resonant frequency of dispersive model is slightly lower than nondispersive model, meanwhile, the input impendence for the dispersive substrate model is lower than the nondispersive model. To summarize, we use Finite-Difference Time-Domain algorithm to simulate the Left-Handed materials electromagnetic properties in this paper, and in the process we propose the high accurate and efficient Piecewise-Linear-Recursive-Convolution Weakly-Conditional-Stability algorithm for dispersion medium.更多还原