电磁坐标变换及其应用研究

【作者】 杨成福；

【导师】 黄铭；

【作者基本信息】 云南大学 ， 通信与信息系统， 2010， 硕士

【摘要】 2006年Pendry等人在Science杂志上发表基于电磁坐标变换实现电磁斗篷的方法,稍后这一理论结果被Schurig等人实验证实。此后,电磁坐标变换及其电磁斗篷现象成为科学研究的热点,并被Science杂志评为年度十大科技进展之一。除利用坐标变换方法设计电磁斗篷外,许多新型的电磁装置也被提了出来。本文分析了电磁坐标变换的基本原理,导出了任意形状电磁透明体和电磁聚焦装置的材料电磁特性方程,并讨论了电磁特性参数对其性能的影响;导出了任意形状电磁外斗篷的材料电磁特性方程,并详细研究了不同坐标变换对斗篷性能的影响。同时,通过有限元软件COMSOL验证了上述结论,进一步证实了本文提出的方法的有效性和正确性。论文的主要内容包括以下四部分:第一部分首先介绍了电磁坐标变换的原理,随后重点讨论了如何利用电磁坐标变换设计各种形状的封闭式电磁斗篷。第二部分导出了正多边形、共形和非共形任意形状电磁透明体的材料电磁特性方程,通过仿真证实了这些方程的有效性,并探讨了电磁透明体在天线保护中的应用。第三部分导出了椭圆形、正多边形、共形和非共形任意形状电磁聚焦器的材料电磁特性方程,通过仿真证实了这些方程的有效性,探讨了电磁聚焦装置在太阳能利用及传感应用的可能性。第四部分导出了椭圆形、正多边形以及任意形状电磁外斗篷的材料电磁特性方程,详细研究了不同坐标变换对斗篷特性的影响,发现通过坐标变换后物质和反物质的形状不一样,并且为了隐形相同的物质,基于非线性变换的反物质更小,这为设计小型隐形装置奠定了理论基础。更多还原

【Abstract】 The design of electromagnetic cloak based on coordinate transformation theory was firstly proposed by Pendry et al in 2006. Later, this theory was experimentally demonstrated by Schurig, which made the coordinate transformation and the phenomenon of cloaking a hot spot of scientific research. It was evaluated by Science as one of the year’s top ten scientific and technology developments. Since then, many novel devices based coordination transformation were proposed to manipulate the propagation of electromagnetic wave.Based on the theory of coordination transformation, this thesis developed the material parameter equations for electromagnetic transparent devices and concentrators with arbitrary geometries. The influence of the material parameters on the characteristics of the devices was analyzed. Besides, the material parameter equation for the arbitrary shaped external cloak was derived. The performance of the external cloak based on linear and nonlinear coordinate transformations are compared with each other and discussed in detail. All the theoretical results were validated by numerical simulation using the finite element software COMSOL. The main contents and conclusions obtained are as follows.In the first part, the coordinate transformation theory was introduced, and its applicationin the design of arbitrary shaped electromagnetic cloak which hidden an object by enclosing it in the cloaking shell was discussed in detail.In the second part, material parameter equations for the transparent device with regular polygonal cross section as well as arbitrary cross section of conformal and non-conformal boundaries were developed, and validated by numerical simulation. The application of the transparent device in the protection of antenna was investigated.In the third part, the electromagnetic concentrator was studied. Material parameter equations for the elliptical concentrator, the regular polygonal concentrators as well as the arbitrary shaped concentrators with conformal and non-conformal inner and outer boundaries were developed and validated by numerical simulation. The phenomenon of field concentration of light plays an important role in the harnessing of light in solar cells similar devices. It is expected that this work is helpful for the designing concentrators in electromagnetic and optical fields, where high field intensities are required.In the fourth part, material parameter equations for the elliptical external cloak, regular polygonal external cloak, as well as the external cloak with arbitrary geometries were developed. The performance of the cloak based linear coordination transformation was studied and compared with that based on non linear transformation. It’s found that the shape and size of the“antiobject”is dependent on the contour of the cloak and the coordination transformation. Interestingly, the object with much larger size can be hidden by the cloak based on non-linear transformation, which shows some advantages in open up an avenue for miniaturization in future cloak design.更多还原