【作者】 朱磊；

【导师】 吴群；

【作者基本信息】 哈尔滨工业大学 ， 微电子学与固体电子学， 2014， 博士

【摘要】 在超介质中模拟实现电磁感应透明(Electromagnetically Induced Transparence,EIT)现象近年来受到了电磁界的日益关注,是目前超介质研究领域的热点问题之一。然而,具有EIT效应的超介质(简称EIT超介质)作为一门新兴科学还有很多问题需要解决。相比于其它超介质,EIT超介质具有更为特殊的工作机制,这致使优化EIT超介质的电磁性能具有重要的理论研究价值和现实指导意义。因此,本论文以微波段EIT超介质电磁激发机理研究为切入点,采用机械振子模型、等效电路模型深入分析了超介质中EIT效应的产生物理机制和关键性影响因素,研究了EIT超介质的构造方法,并完成了EIT超介质在微波器件应用中的性能测试和实验验证。首先,本文针对超介质中EIT效应的电磁激发机理展开研究,从不同角度建立了EIT超介质结构吸收功率解析模型,深入分析了超介质中EIT效应的产生原因和影响因素,探索了EIT超介质的工作机制和激发机理,并利用Matlab仿真工具对所建立的解析模型进行了仿真验证与分析。其次,本文针对微波段EIT超介质构造方法进行研究,在EIT超介质电磁机理研究基础上,提出了具有优良电磁特性的三种不同类型EIT超介质构造方法,即多通带EIT超介质、可调谐EIT超介质以及基于微带线耦合EIT超介质的构造方法。文中利用数值仿真和实验测试证实了上述EIT超介质构造方法的正确性。再次,本文利用EIT效应的高透波率和强色散特性在微波段设计了一种基于EIT超介质的极化变换器。所设计的超介质结构对于x极化和y极化入射波,在9.2GHz的传输幅度相等(~0.72),传输相位差约为90,因而高度透明的线-圆极化变换能够应用EIT超介质结构来实现。此外,基于EIT超介质的极化变换器厚度超薄,仅为0.017?,比目前已报道的极化变换器厚度减少了2/3。文中利用数值仿真和实验测试证明了所设计极化变换器的正确性。最后,本文基于EIT效应的强色散特性,研究了EIT超介质的窄带变极化特性。本文设计的EIT超介质结构能在一个极窄频率间隔内(相对带宽1.3%),通过改变工作频率实现线-圆极化、线-椭圆极化和线-线极化之间的切换。文中利用数值仿真和实验测试证明了所设计的EIT超介质具有窄带变极化特性。本论文从上述几个方面通过探索EIT超介质的电磁激发机理,总结归纳了微波段EIT超介质的构造规律和实现方法,并完成了EIT超介质在微波器件应用中的实验验证,对未来微波器件的实现具有重要指导意义。本论文的研究成果不仅有助于人们更加深入地理解EIT超介质电磁激发机理,而且还促进了EIT超介质在实际应用中的快速发展,对推动EIT超介质向更深层次发展具有重要的科学研究意义和实际价值。更多还原

【Abstract】 Recently, analogues of electromagnetically induced transparency(EIT) effects in metamaterials have received increasingly attention in electromagnetic fields. The EIT effect is one of hot issues in research areas of metamaterials. However, there are still many problems to be solved because the metamaterial with EIT effect(i.e. EIT metamaterial) is an emerging science. Constrast with other metamaterials, EIT metamaterial owns the more special work mechanism, and thus the optimizing of electromagnetic performance for EIT metamaterial has important theoretical research value and practical guiding significance. Therefore, in this paper, the electromagnetic mechanisms of microwave EIT metamaterials are taken as our breakthrough points. Using the mechanical oscillator model and the equivalent circuit theory, the generated mechnisms and key influence factors of EIT effects in metamaterials are analyzed. The construction methods of EIT metamaterials are investigated, and the performance tests and experimental verifications of EIT metamaterials in applications of microwave devices are accomplished.Firstly, the excitation mechinism of EIT effect in metamaterial is investigated. The analytical models of absorption power for EIT metamaterial are established from different angles. The generation reasons and influence factors of EIT effects in metamaterials are deeply analyzed. The working mechanism and excitation mechanism of EIT metamaterial are also explored. Moreover, Matlab simulation tool is used to analyze and verify the effectiveness of above analytical models.Secondly, the construction method of microwave EIT metamaterial is investigated. Based on the electromagnetic excitation mechanism of EIT metamaterial, three construction methods for EIT metamaterials with excellently electromagnetic properties are proposed, i.e. multi-band EIT metamaterial, tunable EIT metamaterial and EIT metamaterial based on microstrip line couplings. The effectivenesses of construction methods for EIT metamaterials are verified by numerical simulations and experimental measurements.Thirdly, this thesis designs a microwave polarization converter based on EIT metamaterial by using the high transmittance and strong dispersion property of EIT effect. For x- and y-polarization incident waves, the transmission coefficients of the designed metamaterial are same at 9.2GHz(~0.72), and their phase difference is 90-degree. Therefore, the highly transparent linear-to-circular polarization conversion can be achieved by using the EIT metamaterial. In addition, the thickness of polarization device is ultra-thin(~0.017l), and its thickness decreases two thirds than that of the reported polarization device. The effectiveness of the polarization converter is verified by numerical simulations and experimental measurements.Finally, this thesis investigates the narrow-band variable polarization properties of EIT metamaterial based on strong dispersion property of EIT effect. The designed metamaterial can achieve the linear-to-circular, linear-to-ellipse, and linear-to-linear polarization conversions in an extremely narrow frequency interval by altering the operating frequency. The narrow-band variable polarization properties of EIT metamaterial are demonstrated by numerical simulations and experimental measurements.From the above several aspects, by exploring the electromagnetic excitation mechanisms of EIT metamaterials, this thesis summarizes the construction rules and realization methods of microwave EIT metamaterials, and accomplishes experimental verifications of EIT metamaterials in applications of microwave devices, which have important guiding significance for the realizations of the microwave devices in the future. The research achievements of this thesis will not only help people to deeply understand the electromagnetic excitation mechanisms of EIT metamaterials, but also promote the rapid developments of EIT metamaterials in practical applications, which have important scientific significances and practical values for promoting the deeper developments of EIT metamaterials.更多还原