【作者】 高嵩；

【导师】 毕科；

【作者基本信息】 北京邮电大学 ， 电子科学与技术， 2024， 博士

【摘要】 介质基超表面是由介质谐振单元构成的二维人工材料,通过精确设计介质材料在微观尺度的排列和形状,在亚波长尺度操控电磁波的传播,从而实现电磁波行为的特殊调控。尤其是在微波和太赫兹波段,超表面单元结构设计的理想尺寸能够高度兼容现有成熟的微加工工艺与技术。相比于传统的金属基超表面,介质基超表面具有低损耗、高品质因数(Qualityfactor,Q)、易于集成、低加工成本等显著优势,逐渐广泛应用于生物传感器、可调谐吸波器和医学检测等领域。本文针对金属基超表面在可调性、传输损耗及加工精度上的局限性,系统研究了介质基超表面的设计方法和调控原理,利用硅基自组装模版法、金属模版法以及基于3D打印工艺的模版法,成功制备了具有特定功能的微波和太赫兹介质基电磁功能器件。基于介质材料的电磁性能随外部磁场等因素变化的响应特性,提出了可调谐的吸波器以及高灵敏度、高稳定性的生物传感器设计,为介质基超表面在精细电磁调控方面的应用提供了新的设计思路和研究范式。本论文围绕介质基超表面的工作机理、仿真设计、性能调控、器件研制、实验验证等方面开展了深入探究,主要创新成果包括以下几个方面:(1)在太赫兹波段,提出了一种基于液晶的新型可调谐介质基超表面吸波器的设计。不同于传统介质基吸波器件专注于第一、第二模态Mie氏谐振的研究,通过对前三模态Mie氏谐振调谐性能系统分析的基础上,优化并确定了晶胞中的介质微球尺寸为60 μm的吸波器,在高模态下获得高达6.67的调谐品质因数,并进一步利用硅基模版法成功制备了基于液晶溶液的可调谐吸波器。(2)在太赫兹波段的传感器研究中,设计了高Q值单微球结构的氨基酸检测的生物传感器。该传感器在敏感度和稳定性方面取得显著优势,其品质因子、灵敏度(Sensitivity,S)和性能指标(Figure of Merit,FOM)达到 657.93、114.75 GHz/RIU、28.25;为了进一步提升传感器的性能,通过系统优化单元结构,使其Q值、S值和FOM的最高值分别达到了 451.87、135.00 GHz/RIU和42.19。在利用硅基模版法制备的基础上,成功提出了改进的金属模版制备法,能够实现灵敏且精确的传感器制备。(3)在微波频段,开发了基于氧化锆陶瓷球的超表面吸波器,通过电磁数值仿真模拟的方法,成功预测了其调谐性能的可行性和高效性,并明确了不同尺寸陶瓷球的最佳结构参数,设计并开发了基于3D打印技术的可调谐吸波器模版法制备工艺,所制备吸波器的吸收率不低于0.874且第三模态最大调谐范围为0.3101 GHz。(4)本文针对微波段有机油类超表面传感器进行了开发与性能优化,通过对晶胞结构不同尺寸的仿真分析,证明了所提出的传感器对不同油类具有良好的识别能力,其最大识别范围为0.265 GHz,对不同油类的吸收率均不低于0.885,且传感器的Q值与FOM最高达到了93.35和27.94。更多还原

【Abstract】 Dielectric-based metasurfaces,comprised of resonant dielectric elements arrayed bidimensionally,allow for the manipulation of electromagnetic waves at sub wavelength scales through precise microscale engineering of material arrangements and configurations,thereby enabling specialized control over electromagnetic wave behaviors.In the microwave and terahertz frequency ranges,the design of metasurface elements at the ideal micron to millimeter scales is highly compatible with established microfabrication techniques.With notable advantages over conventional metallic metasurfaces,such as lower losses,higher quality factors,ease of integration,and reduced fabrication costs,dielectric metasurfaces are extensively applied in fields like biosensors,tunable absorbers,and medical diagnostics.Addressing the limitations of traditional metallic metamaterials in terms of tunability,transmission losses,and fabrication precision,this study systematically explores the design methodologies and tuning principles of dielectric metasurfaces.Utilizing silicon-based self-assembly and 3D printing templating methods,electromagnetic functional devices for microwave and terahertz applications with specific functionalities have been successfully fabricated.Leveraging the responsive characteristics of dielectric materials to external factors such as magnetic fields,this work proposes designs for tunable absorbers,and biosensors with high sensitivity and stability,offering novel insights and paradigms for the application of dielectric metasurfaces in sophisticated electromagnetic modulation.This dissertation conducts a thorough and systematic investigation into the operational mechanisms of dielectric metasurfaces,simulation design and performance tuning,device fabrication,and experimental validation,with the main innovations and achievements encompassing the following aspects:(1)In the terahertz frequency band,a novel tunable all-dielectric metasurface absorber design based on liquid crystals is proposed.Unlike conventional dielectric-based absorber devices that focus on the first and second modal Mie resonances,this thesis,based on a comprehensive analysis of the tuning performance of the first three modal Mie resonances,optimizes and determines the dielectric microsphere size of 60μm in the unit cell to achieve a high tuning quality factor of up to 6.67 in high-order modes.Furthermore,using silicon-based template methods,we have successfully fabricated a tunable absorber based on liquid crystal solutions.(2)In terahertz sensor research,a high Q-factor single microsphere structure biosensor for amino acid detection has been designed,which achieves significant advantages in sensitivity and stability.The quality factor,sensitivity(S),and performance index(figure of merit,FOM)reached 657.93,114.75 GHz/RIU,and 28.25,respectively.To further enhance the sensor’s performance,through systematic optimization of the unit structure,the highest Q,S,and FOM achieved were 451.87,135.00 GHz/RIU,and 42.19,respectively.Moreover,building on the silicon-based auxiliary template fabrication method,a metal template fabrication method is proposed,achieving rapid and precise sensor fabrication.(3)In the microwave frequency band,the thesis has developed a zirconia ceramic ball-based metasurface absorber.The electromagnetic numerical simulation method predicts its tunability’s feasibility and efficiency,and the optimal structural parameters of ceramic balls of different sizes are clarified.The tunable absorber fabrication process using 3D printing technology has been designed and developed,with the fabricated absorbers achieving an absorption rate of no less than 0.874 and the third modal maximum tuning range of 0.3101 GHz.(4)For microwave frequency band organic oil-based metasurface sensors,development and performance optimization are conducted.Through simulation and analysis of different size structures,the proposed sensor has been proven to have good recognition capabilities for different oils,with a maximum recognition range of 0.265 GHz.The absorption rate for different oils is no less than 0.885,and the sensor’s Q-value and FOM have reached up to 93.35 and 27.94.更多还原