【作者】 饶芳；

【导师】 杨河林；

【作者基本信息】 华中师范大学 ， 信号与信息处理， 2018， 硕士

【摘要】 电磁超材料不能在自然界中直接获取,只能通过人工复合材料合成,具有特异性质。在这种新型材料被理论与实验验证后,对其应用的研究才得以陆续开展。随之即出现了大量如滤波器、耦合器、传感器、天线、吸波材料等基于超材料理论的研究应用。近年来随着超材料研究应用的发展,如SRRs的超材料基本单元结构被发现可以明显提高传感设备的灵敏度。特别是其在非接触式的生物检测方面有巨大潜在应用前景,相比宏观物质的检测更简便且灵敏度更高。与传统的机械传感器及纳米材料传感器相比,超材料传感器在军事科学、医疗监控、临床实验与诊断、环境污染检测以及生物化学工程条件控制等领域具有显著的应用价值。因此,利用超材料微波特性来设计高灵敏度的实时探测传感器已经成为一个研究热门。本文分别基于CSSR和SRR设计了两种超材料传感器,并通过等效电路理论分析结构的谐振特性及传感特性。先利用CST微波工作室进行模型仿真与优化,再利用矢量网络分析仪分别进行同轴馈电实验测试,数值仿真结果与实验结果基本一致。本文主要工作总结如下:(1)利用互补单开缝谐振环(CSSRR)与一个圆环形微带线设计、仿真及实验验证了一种无接触式的新型角位移传感器,测试结果与仿真结果吻合。通过等效电路模型分析了传感器的工作原理和不同角度下的传感特性。提取等效电路参数进行电路仿真,其结果与实验测量结果基本一致。该传感器结构非常紧凑,当旋转角度在30°、60°和90°时,灵敏度分别为0.21、0.43和0.77。这类传感设备在微机电系统的进一步集成化中具有潜在的应用价值。(2)设计了一种基于半圆开缝谐振环(SRR)的高灵敏度气液多用传感器,并仿真分析了其对于常温下气体及液体的感应曲线。该传感器的设计基于改进型开缝环(SRR)与U形微带线耦合,构成具有高品质因数(Q),工作频率接近1.75 GHz的LC谐振回路。在开缝环形结构与微带传输线之间设计电容间隙以实现高电场强度。该区域中气体或液体浓度的微小变化会引起传感器周围环境等效介质的改变,从而导致谐振频率发生显著变化。不同气体及液体的分子密度和特异性可以通过检查共振频率的变化、传输系数的Q值来确定。本传感器结构紧凑,能良好地集成在微型芯片中,也可在将来应用于小型电子鼻的设计制作中。更多还原

【Abstract】 Metamaterials with specific properties cannot be directly obtained in nature but only be synthesized by artificial composite materials.After the new material was verified by theories and experiments,the research on its application was gradually carried out.Subsequently,a large number of research applications based on metamaterials such as filters,couplers,sensors,antennas,and absorber have appeared.In recent years,with the development of the research and application of metamaterials,the basic unit structure of metamaterials such as SRRs has been found to significantly improve the sensitivity of sensing devices.In particular,it has a huge potential application prospect in non-contact biological detection,which is simpler and more sensitive than macroscopic material detection.Compared with traditional mechanical sensors and nanomaterial sensors,metamaterial sensors have significant application value in military science,medical monitoring,clinical experiment and diagnosis,environmental pollution detection,and biochemical engineering condition control.Therefore,the application of metamaterials to design high-sensitivity microwave sensors has received more and more attentions.We designed two kinds of metamaterial-inspired sensors based on CSSR and SRR,respectively,and resonant characteristics and sensing characteristics of the structure are analyzed through equivalent circuit theory.First,we use the CST microwave studio for model simulation and optimization,and then use the vector network analyzer coaxial feed for testing.The numerical simulation results are in consistent with the experimental results.The main work of this paper can be summarized as follows:(1)We proposed a complementary single-opening resonant ring(CSSRR)and a circular microstrip line to realize a non-contact rotation sensor.The experiment results are in good agreement with the simulation.The working principle of the sensor and the sensing characteristics under different angles are analyzed through the equivalent circuit model.The results of circuit simulation,performed by extracting the equivalent circuit parameters,are consistent with the experimental results.The compact sensor has sensitivities of 0.21,0.43 and 0.77 at angles of 30°,60° and 90°,respectively.This kind of sensing device has potential applications in the further integration of MEMS.(2)A gas-liquid sensor is based on Semicircular-split resonant ring(SRR)was designed with high sensitivity,and its induction curves for gas and liquid at room temperature was simulated.The design of this sensor is based on an improved spilt-resonant ring(SRR)coupled with a U-shaped microstrip line,which constitutes an LC resonant tank with a high quality factor(Q)and operating frequency close to 1.75 GHz.A capacitive gap is designed between the split-ring structures and the split-microstrip line to achieve high electric field strength.A small change in the concentration of gas or liquid in this area cause a slight change in the equivalent medium around the sensor,resulting in a substantial change of the resonant frequency.The molecular density and specificity of different gases and liquids can be determined by examining the change in resonance frequency and the Q factor of the transmission coefficient.The sensor is compact in structure,and can be well integrated in the design of microchip,and can also be applied to the design of a small electronic noses in the future.更多还原