标题: | 人造电磁材料之特性分析与应用研究 Emission Control Using Artificial Electromagnetic Materials |
作者: | 黄瑞彬 HWANG RUEY BING 国立交通大学电信工程学系(所) |
关键字: | 人造电磁材料;超颖材料;周期性结构;负折射;Artificial Electromagnetic Materials;metamaterials;periodic structures;negative refraction |
公开日期: | 2009 |
摘要: | 人造电磁材料的电磁特性是由它的周期以及单晶胞图案而來,反倒与其组成成分没有直接关聯。一般來說,人们藉由在主介质中嵌入特殊内容物,例如:周期性结构,來合成超颖材料。近年來,由于超颖材料(或称人造电磁材料)不寻常且惊人的电磁波传导特性,像是负折射现象和负群延迟现象,吸引了许多目光。即使这些不寻常的现象已经在數值上和理論上被证实,波在超颖材料中的传导过程所隐含的物理意义仍然需要详细的探索。 在本计划中,我们将目标放在研究如何利用人造电磁材料导引电磁波的传导与輻射。在第一年,我们将使用Floquet-Bloch理論來探索波在人造电磁材料中传导的基本原理。如此一來,我们在合成一个具有任意相位关系的人造电磁材料时会有很大的优势。在第二年,我们将研究使用平面或三维人造电磁材料时,其反射主波束扫描的电磁梯度面。重点将会放在增加频宽并解决频率相关造成主波束扫描的问题。在第三年,我们探讨将一个线波源嵌入超颖材料中所造成的波束调整特性。近來來,这样的问题已经被深入的研究。人们提出许多方法來解释此种超颖材料的波束调整特性,举例來說:将超颖材料视为一个具有负介电系數及负导磁系數之均匀介质的等效介质理論。然而,当我们在解包含金属与普遍被使用的介质材料的实际结构的马克思威尔方程式时,理所当然,我们知道在那样的环境下,其电能和磁能必然是正实數。在这裡,超颖材料(或称人造电磁材料)将会被视为一个频率选择结构,并且我们将使用全波分析,也就是频域分析法,來计算频域中的感应电流。 这项子计画结合了主计画发展高速传收系统的目的。在本计划中所发展的人造电磁材料将会用來当作一个控制电磁波輻射的元件,而这些电磁波是由其他子计画发展的天线所产生的。最后但并非最不重要的一点,本计划的其他目的是促进研究生在理論及工程上的研究,以提升他们在应用电磁学上设计之兴趣。 Artificial Electromagnetic Materials (AEMs) is a material gaining its electromagnetic properties form its structure configuration including period and unit cell pattern rather than directly from its composition. In general, a metamaterial is synthesized by embedding specific inclusions, for example, periodic structures, in a host medium. Recently, metamaterial or AEMs attract considerable attentions due to its extraordinary and amazing properties of wave propagating; such as the negative refraction phenomena and negative group velocity. Although those extraordinary phenomena were numerically and theoretically verified, the underlying physics of wave process involved in meta-materials remains to be investigated in detail. In this proposal, we aimed at studying the emission control using AEMs. In Phase 1, we will employ the Floquet-Bloch theory to investigate fundamentals of wave propagating in an AEM; especially for the dispersion- and phase- relation of wave propagating. In doing so, we will have a good position to synthesize an AEM having an arbitrary phase relation. In Phase 2, we will study an electromagnetic gradient surface for reflected beam steering utilizing a 3D or planar AEM. The emphasis will be placed at the bandwidth improvement and resolve the problem of frequency-dependent steering angle. In Phase 3, we will investigate beam-shaping characteristics of a line source embedded in a metamaterial. Such a problem has been intensively studied in recent years. Several methods were proposed to interpret the beam-shaping property of the meta-materials; for example, the effective medium theory considering the meta-material as a uniform medium with negative permittivity or permeability. However, we know that the electric and magnetic energy in such an environment, of course, are positive and real numbers when we solve Maxwell’s equations for the real structure containing a metal and a commonly used dielectric material. Here, the meta-material (or AEMs) will be regarded as a frequency-selective structure and a full-wave method: spectral domain analysis will be employed to calculate the induced current in spectral domain. This subproject joints the main project to develop a high-speed transceiver system. The AEMs developed in this project will be employed as a device to control the emission of electromagnetic wave generated by the antennas developed in the other subprojects. Last but not least, the other objective of this project is to promote theoretical and engineering research for the graduate student, to raise their interest on the design of applied electromagnetics. |
官方说明文件#: | NSC98-2221-E009-038 |
URI: | http://hdl.handle.net/11536/101855 https://www.grb.gov.tw/search/planDetail?id=1909599&docId=316660 |
显示于类别: | Research Plans |
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