石墨烯对电磁波调控机理及应用研究

发布时间：2018-03-27 15:16

本文选题：石墨烯　切入点：电磁材料　出处：《东南大学》2017年博士论文

【摘要】：近来来,石墨烯作为一种二维碳材料正在吸引着国内外学者的广泛关注和研究热潮。由于这种新型材料具备特异属性,其在电子、材料、物理、化学、生物医学等学科展现了广阔的应用前景。本文从电磁学角度出发,研究了石墨烯的可调控特征,并进一步利用此特征探索了基于表面波与空间波类型的电磁功能器件设计机理与典型应用案例。本文的主要工作及其创新点概括如下几点:1.系统分析、概括了石墨烯及其结构不同的加工制备方法,总结了各种方法在应用上适合的场景,以及各种方法对应电磁参数的大致取值范围,这些工作奠定了石墨烯实用化的基础。2.全面分析了石墨烯全频段电磁特性,基于此探讨了不同工作频率条件下的石墨烯电磁参数表示方法。总结了石墨烯不同的调控手段,并根据调控效率指出了当前设计基于石墨烯的电磁器件最有效的调控技术的发展方向。3.回顾了石墨烯支持的表面波模式,并着重介绍了 TM模式表面波的传播特性,在此基础上,进一步研究了石墨烯边缘模式的表面波,分析对比了两种边缘模式,并讨论了两种模式的各自特点。4.基于石墨烯表面波提出了几种典型的电磁器件,利用石墨烯纳米条带上边缘模式表面波的干涉特性、耦合特性、谐振特性研究了逻辑门、平面、立体谐振环。a).通过调节石墨烯条带的长度,石墨烯偶边缘模式表面波能够有效相干相消或者相干增强,并且设计的逻辑门(异或门、同或门)比传统的介质、金属结构要更加紧凑;b).通过求解超越方程得到石墨烯圆环的本征模式,并通过石墨烯直条带将能量耦合到圆环上,展示了这种平面谐振环具有明显的通、阻带作用,并且谐振谱可以通过石墨烯的化学势调控,基于此进一步设计了一种四状态开关;c).在本课题组之前的研究基础之上,本文进一步展示了石墨烯与传统的金属材料对表面波束缚的差异,即便是将石墨烯条带弯曲成360°其仍然能够支持传播表面波,并使用石墨烯直条带可以将电磁信号耦合到这种立体环结构上,实现了与平面结构类似的频谱特性。5.回顾并总结了石墨烯与空间波的相互作用形式,从石墨烯本身与电磁波的作用比较微弱的角度开始阐述,逐步深入地探讨了若干种增强相互作用的结构。6.在对石墨烯与空间波作用机理理解的基础之上,分别提出了以下几种电磁器件应用案例:a).石墨烯调控Fabry-Perot谐振腔可以实现对反射波的幅度和相位进行有效控制,其中相位在三个工作频点附近的变化范围分别达到了 310°、260°、215°,根据这三个频点的变化范围针对性地设计了三种不同的阵列排布方法,实现了对反射波束的有效控制;b).研究了一种石墨烯与介质棒的复合非谐振结构,这种复合结构在宏观上的等效电磁参数具有可调控特性,例如,在25THz处,等效折射率可以在1～2范围内变化,数值仿真结果证明,这种结构可以作为“数字超材料”的“比特单元”,并演示了异常透射、龙伯透镜、电磁“黑洞”案例;c).研究了一种石墨烯互补开口谐振环结构,这种结构具有与对应的正结构类似的频谱特征,两者的谐振机理予以细致分析对比,本文提出的互补结构结合石墨烯的调控方法,具有一致调控的优势;d)提出了一种石墨烯双回结构微波吸波器结构,这种结构印制在柔性材料上,并在上下层之间填充电解质实现对石墨烯的高效调控,在石墨烯表面阻抗达到60Ω/sq时候,可以在5～20GHz宽带范围实现吸收效率90%以上的吸波效果。本文的相关研究成果己发表在国际知名期刊IEEE Photoncs Technology Letters,Plasmonics,Journal of Physics D:Applied Physics、Europhysics Letters,其中第一作者四篇;国际会议International Symposiumal on Antennas and Propagation、Progress In Electromagnetics Research Symposium、Asia-Pacific Micro wave Confrence,其中第一作者两篇。截止目前发表的文章被引用次数达到40(googlescholar)。这些研究成果在一定程度上促进了我国在石墨烯电磁学领域内的研究步伐,对未来在此领域内的学术和应用研究提供一些参考。
[Abstract]:Recently, graphene is a two-dimensional carbon material is attracted extensive attention of scholars and researchers. Because of this new material with specific properties, in the electronic, material, physics, chemistry, biomedical science show a broad application prospects. In this paper, from the perspective of electromagnetics, control characteristics of graphite graphene, and further explore the function of using this feature of electromagnetic device design mechanism of surface wave and wave type and typical application based on the case. The main work and innovation are summarized as follows: 1. system analysis, summarized the process of graphene and its structure of different preparation methods, summarizes the various methods for the application of the scene, as well as various methods corresponding to the approximate range of electromagnetic parameters, these work laid the foundation for.2. graphene practical comprehensive analysis of the Shi Moxi band Based on the electromagnetic characteristics, discusses the electromagnetic parameters of graphene conditions under different frequencies of representation. Up regulation means different graphene, and according to the regulation efficiency and pointed out the development direction of control technology based on the design of electromagnetic devices graphene is the most effective.3. review of the surface wave mode of graphene supported, and introduced emphatically the propagation characteristics of TM wave mode, on this basis, further research on the surface of graphene edge model, comparative analysis of two kinds of edge model, and discusses the respective characteristics of two kinds of.4. model is proposed based on graphene surface wave electromagnetic devices of several typical interference characteristics of graphene nanoribbons on edge pattern the coupling characteristics of planar resonant characteristics of logic gates, stereo resonant ring.A). By adjusting the graphene strip length, graphene edge pattern pairs The surface wave can effectively interference or coherent enhancement, and the design of the logic gate (XOR gate, XNOR gate) than the traditional medium, metal structure to be more compact; b). Through the eigenmode equation obtained graphene rings, and the graphene strip will direct energy is coupled into the ring, show the planar ring resonator has obvious, stopband, and resonance spectrum of graphene by chemical potential control, the design of a further four state switch based on C).; based on our previous, this paper further shows the difference with the traditional metal materials of graphene on the surface even the beam bound, the graphene strip bent to 360 degrees it can still support the propagation of surface acoustic wave, and the use of graphene strip can be directly coupled to the electromagnetic signal of this three-dimensional structure, and the realization of the plane structure .5. spectrum like reviews and summarizes the interaction with the spatial form of graphene, graphene itself from the electromagnetic wave and the role of the weak point of view to elaborate, gradually discussed several kind of reinforcing structure.6. interaction based on the understanding of graphene with the spatial mechanism, are presented below several application cases of electromagnetic devices: a). The regulation of graphene Fabry-Perot resonant cavity can effectively control the amplitude and phase of reflection wave, the phase change range in the vicinity of the three working frequency reached 310 degrees, 260 degrees, 215 degrees, according to the range of the three frequency points to the design of three different array methods, to achieve effective control of the reflected beam; b) was studied. A composite non resonant structure of graphene and dielectric rod, the composite structure in the macro Effect of electromagnetic parameters can control characteristics, for example, in 25THz, the equivalent refractive index can be changed in the range of 1~2, numerical simulation results show that this structure can be used as "digital super material" bit unit ", and demonstrates the abnormal transmission, electromagnetic Luneberg lens," black hole "case; C). A graphene complementary split ring resonator structure, this structure has similar structure spectrum corresponding to the resonance mechanism, both to detailed analysis and comparison, control methods of graphene with complementary structure is proposed in this paper, with the regulation of the advantage; d) proposes a graphene double circuit structure of microwave absorber structure, this structure is printed on a flexible material, and in between the upper and lower filling electrolyte to achieve efficient regulation of graphene, achieve 60 ohm /sq when the surface impedance of graphene, in 5 ~ 20GHz wide. The absorption efficiency of more than 90% of the absorbing effect. The results of this study have been published in the International Journal of Plasmonics IEEE Photoncs Technology Letters, Journal of, Physics D:Applied Physics, Europhysics Letters, the first author of article four; International Symposiumal on Antennas and international conference Propagation, Progress In Electromagnetics Research Symposium, Asia-Pacific Micro wave Confrence, which the first author of two articles. The published article cited the number reached 40 (googlescholar). The results of these studies contributed to our country in the graphene electromagnetic field the pace of research to a certain extent, to provide some reference for future research and application in this field.

【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O613.71

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