【作者】 孟繁义；

【导师】 吴群； 吴健；

【作者基本信息】 哈尔滨工业大学 ， 微电子学与固体电子学， 2007， 博士

【摘要】 近年来,左手介质由于其异常的电磁特性在固体物理学、材料科学、光学和应用电磁学领域内获得愈来愈多的青睐。但不可否认的是,左手介质研究作为一门新兴的前沿科学在很多方面还很不完善,仍然处于一种摸索前进的状态,还有很多的基本理论、实践问题亟待解决。基于这样的原因,作者遵循“以左手介质电磁特性分析结合理论创新为基础,以性能优良的左手介质设计承上启下,以利用左手介质改善现有微波器件性能的应用效果为检验标准”的研究思路撰写了本篇论文,进而实现综合发展左手介质研究的目的。首先,本文针对左手介质的异常电磁特性激发机理展开研究。从多个研究角度建立了左手介质本构参数解析模型,并通过多种手段验证了所建立模型的正确性和准确性。本研究所得到的解析模型在保持精度的同时,其推导过程的物理意义更明确,更易于理解。其次,本文针对小单元粒子型左手介质展开研究,设计出工作频段在9.2 ~ 11.8 GHz的微小单元左手介质,其长度最低可以达到0.11个工作波长,相比于国际上已报导的最优结果又缩小了41%。研究中,清晰地观察到了该左手介质的双负特性、后向波特性以及负折射特性,从而验证了该小单元左手介质设计的正确性。最后,本文还基于该左手介质的后向波特性,将其成功应用在小型化贴片天线的设计中,首次应用真实的粒子型左手介质而不是理论模型将普通贴片天线的长度从0.5个工作波长降低到了0.17个工作波长,获得了与理论预测完全吻合的近场分布和远场辐射特性。第三,本研究提出了一种新颖的基于左手介质与负介电常数介质的谐振结构,实现长度和宽度同时得到缩小的超小型矩形金属谐振腔,并利用该谐振腔设计出两种小型化带通滤波器。通过数值仿真和实验测试证实了该小型化谐振腔和滤波器设计的正确性。最后,本文通过对具有平面金属网格的零折射介质进行优化,得到一种具有更好通带特性的零折射介质。而在将其合理地布置在喇叭天线口面内之后,构造出一种基于零折射介质的高增益小型化喇叭天线。研究结果表明该喇叭天线相比同尺寸的普通喇叭天线在1.1GHz带宽上增益普遍提高2 dB,而轴向尺寸只有最优喇叭的56%。本文的研究成果综合发展了左手介质的相关理论分析方法、设计方法以及应用领域,在更为深刻地向人们展示左手介质异常电磁特性及其激发机理的同时,设计了性能更为优良的左手介质,并将其应用于改善现有微波器件的性能,加快了左手介质向实用阶段前进的步伐,拓宽了左手介质的应用领域,对左手介质相关研究的发展具有重要的指导意义和实用价值。更多还原

【Abstract】 In recent years, the left-handed metamaterial (LHM) has attracted more and more attentions in the fields of solid physics, material science, optics and electromagnetism. However, the detail research on the LHM is just at its beginning stage, and it is still incomplete in many research aspects such as the electromagnetics (EM) analysis of the LHM, the design of the high performance LHM and the applications of the LHM to microwave, radio-frequency and optical devices for the improvement of the performance. In this paper, we make a comprehensive research on the LHM in order to develop the different research directions in a complementary way.Firstly, the essential principle for the left-handed properties of the LHM is deeply investigated. The analytical models for the constitutive parameters of the LHM consisting of SRR and wires are derived based on the constitutive relations and equivalent transmission line theory. The accuracy of these analytical models is verified through different methods. Compared with previously published results, the theoretical derivation process of our analytical models is simpler and clearer, and the corresponding physical concept is easier to understand.Secondly, a particle-type LHM with miniaturized unit cell and broad bandwidth is designed. Its unit cell length is only 0.11 wavelength at the lowest working frequency, and the frequency range, where the LHM is available, is from 9.2 GHz to 11.8 GHz. Compared with other reported LHMs, the unit cell length has been reduced by 41%. The left-handed properties of the designed LHM are demonstrated through detailed discussions of double-negative, backward wave and negative refraction characteristics. Results show that the negative refraction and backward wave phenomena for the LHM are clearly observed in 9.2 ~ 11.8 GHz where the effective permittivity and permeability are simultaneously negative. Moreover, a miniaturized LHM patch antenna dependent on backward wave characteristics of the LHM is proposed, and the length of the patch antenna has been reduced to 0.17 from original conventional 0.5 working wavelength by embedding real particle-type LHM units instead of a theoretical model. Results show that both near field distribution and radiation pattern of the miniaturized patch antenna are in good agreement with the theoretical analysis.Thirdly, a novel resonance structure dependent on above designed LHM is presented and used to design and fabricate an improved miniaturized cavity resonator (IMCR), whose length and width are less than half of a conventional cavity resonator. Compared with the reported miniaturized LHM cavity resonator based on Engheta’s miniaturized resonance structure, both the length and the width reduction for the IMCR have been obtained simultaneously, instead of the miniaturization realized only in the length. The numerical simulations and experimental measurements are used to confirm the performance of the IMCR, and results show that both the simulation results and measurement results are in good agreements. Moreover, two types of cavity filters based on the MCR are designed, fabricated and tested, and the performance is verified by the simulation results and measurement results, which coincide very well with each other.Finally, a miniaturized rectangular horn antenna with the high gain is designed based on an improved zero refraction metamaterial (ZRM). The results show that the gain is enhanced with over 2 dB in the bandwidth of 1.1 GHz compared with a conventional horn antenna, and the longitudinal length shortens to only 56% of that of the optimized horn antenna for the same antenna performance.The analysis, design and application for the LHM are developed in this research. It is summarized as that a LHM with good performance is designed and applied to improve some microwave devices after EM characteristics of the LHM is analyzed. These important research results will be useful for the applications of the LHM to microwave and millimeter wave circuits and devices.更多还原