新型亚波长电磁超材料的设计与应用研究

发布时间：2018-04-24 00:07

本文选题：电磁超材料 + 亚波长　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：电磁超材料(Metamaterial)作为一种具有许多常规媒质不具备的奇异特性的人工媒质，受到了越来越广泛的关注。本文根据电磁超材料的设计理论，设计了高度亚波长小型化的单负、双负电磁超材料，并将其应用于无线能量传输系统中，提高无线能量传输的距离和效率；又从理论方面入手，研究不同种类理想近零折射率材料的等效媒质特性，并将其用于构成高指向性天线的覆层，研究其对天线性能的影响；最后用实际拓扑结构实现了几种近零折射率电磁超材料，并作为覆层与微带天线构成高增益覆层天线，研究其对微带天线性能的改善。本文的主要工作和研究成果包括以下方面：首先，设计了一种两面均为平面螺旋结构的磁导率为负（MNG）电磁超材料，其波长和尺寸比大于307，具有亚波长小型化的特点；又基于MNG电磁超材料的设计方法设计了一种一面为平面螺旋、一面为金属弯折线的双负（DNG或NRI）电磁超材料，其波长与尺寸之比大于253，也具有高度小型化的特征，且根据此种电磁超材料的结构特征提出一种简易的测量方法。其次，将所设计的MNG、NRI电磁超材料应用于无线能量传输系统中，用两个耦合环集成一块、两块、三块及四块MNG或NRI电磁超材料单元构成新型无线能量传输系统，此系统工作于磁谐振耦合机制，当两个耦合环间距离为140mm时，集成三块电磁超材料单元的传输系统与只有两个耦合环组成的无线能量传输系统相比，其传输系数S21从-32.4dB增加到-5.1dB，提高了27.3dB。第三，从理论方面入手，研究了几种近零折射率材料的等效媒质特性，研究发现，对于由介电常数近零（ENZ）的近零折射率材料不完全填充的一个区域而言，其E面电场主要通过近零折射率材料来传输；而对由磁导率近零（MNZ）的近零折射率材料不完全填充的一个区域而言，其H面磁场主要通过近零折射率材料来传输；而对于由介电常数和磁导率双近零（DNZ）的近零折射率材料不完全填充的一个区域而言，其E面电场和H面的磁场都主要通过近零折射率材料来传输；将理想近零折射率材料用作微带天线的覆层构成高指向性天线，ENZ近零折射率材料的覆层将对天线的E面方向图进行压缩汇聚，MNZ近零折射率材料的覆层将对天线H面方向图进行压缩汇聚，而DNZ近零折射率材料将对E面和H面方向图同时进行压缩汇聚，因此方向性提高。第四，用实际拓扑结构实现了几种近零折射率电磁超材料，将其应用于高增益覆层天线，实测与理论研究吻合良好；在基板的一面刻蚀Fishnet嵌套方形贴片结构，另一面刻蚀Fishnet结构将使电磁超材料的相对介电常数和相对磁导率同时近零，，因此实际增益有6.8dB的提高。
[Abstract]:As a kind of artificial medium, electromagnetic metamaterial has attracted more and more attention. According to the design theory of electromagnetic supermaterial, single negative and double negative electromagnetic supermaterials with high subwavelength miniaturization are designed and applied to wireless energy transmission system to improve the distance and efficiency of wireless energy transmission. From the theoretical point of view, the equivalent media characteristics of different kinds of ideal near-zero refractive index materials are studied, and used to form the coating layer of high directivity antenna, and the effect on antenna performance is studied. Finally, several kinds of near-zero refractive index electromagnetic supermaterials are realized by using the actual topology, and used as a cladding and microstrip antenna to form a high gain coated antenna. The improvement of the performance of the microstrip antenna is studied. The main work and research results of this paper include the following aspects: Firstly, a kind of magnetic supermaterial with both plane helical structure and negative magnetic permeability is designed. The ratio of wavelength to size is larger than 307 and has the characteristic of subwavelength miniaturization. Based on the design method of MNG electromagnetic supermaterial, a double negative DNG or NRI electromagnetic supermaterial with a plane spiral and a metal bending line is designed. The ratio of wavelength to size is larger than 253, and it also has the characteristics of high miniaturization. According to the structural characteristics of the electromagnetic supermaterial, a simple measurement method is proposed. Secondly, the designed MNGNRI electromagnetic supermaterial is applied to the wireless energy transmission system. Two coupling loops are integrated into one piece, two pieces, three blocks and four MNG or NRI electromagnetic supermaterial units to form a new wireless energy transmission system. The system works on the magnetic resonance coupling mechanism. When the distance between the two coupling rings is 140mm, the transmission system which integrates three electromagnetic supermaterial elements is compared with the wireless energy transmission system which consists of only two coupling loops. The transmission coefficient S21 was increased from -32.4dB to -5.1dB, which increased 27.3 dB. Thirdly, the equivalent media properties of several near-zero refractive index materials are studied theoretically. It is found that for a region not fully filled with near-zero refractive index materials with dielectric constant near zero, The E-plane electric field is mainly transmitted by near-zero refractive index material, while for a region not filled with near-zero refractive index material with permeability near zero, the H-plane magnetic field is mainly transmitted by near-zero refractive index material. For a region that is not completely filled with near-zero refractive index material with both permittivity and permeability, the electric field on E plane and magnetic field on H plane are mainly transmitted by near-zero refractive index material. Using ideal Near-Zero Refractive Index material as coating of microstrip Antenna to form a High directivity Antenna ENZ Near-Zero Refractive Index material Coatings will compress and converge the E plane pattern of the Antenna; MNZ Near-Zero Refractive Index material coating will be applied to the antenna H The plane pattern is compressed and converged. The near-zero refractive index material of DNZ will compress and converge the patterns of E plane and H plane at the same time, so the directivity is improved. Fourthly, several kinds of near-zero refractive index electromagnetic supermaterials are realized by using practical topology, which are applied to high gain cladding antennas. The measured results are in good agreement with the theoretical study, and the Fishnet nested square patch structure is etched on one side of the substrate. Etching the Fishnet structure on the other side will make the relative permittivity and relative permeability of the electromagnetic supermaterial near zero at the same time, so the actual gain is increased with the increase of 6.8dB.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN820

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