热控制智能红外吸波结构

发布时间：2018-04-29 04:31

本文选题：人工电磁超材料 + 红外吸波结构　；参考：《电子科技大学》2017年硕士论文

【摘要】：近年来,红外吸波结构由于具有独特的电磁谐振特性成为了人工电磁超材料领域的研究热点。同时,随着相变材料的快速发展,其在红外吸波结构中也得到了广泛的应用,使得该类材料不仅具有人工电磁超材料的功能特性,而且也变得更加智能化,其研究价值和应用前景也越来越广阔。本文以经典的金属-介质-金属的“三明治”吸波结构为研究对象,采用具有热致相变特性的VO2薄膜分别作为金属层和介质层材料,研究了VO2薄膜在不同状态下相对介电常数的色散特性,据此设计了具有热控制特性的智能红外吸波结构并对其工作机理进行分析验证。本论文的创新性和相关研究成果主要有以下几点:(1)研究了相变材料VO2薄膜在金属态、半导体态、相变过渡态以及复合态下相对介电常数的色散特性,通过非线性拟合和有效媒质理论,得到所制备VO2薄膜在各状态下的相对介电常数及其色散特性,认为所采用的色散模型不仅拟合方法简单、拟合结果准确度高,而且还适用于具有复合相或杂质相的复合材料。(2)以VO2薄膜分别作为吸波结构的金属层和介质层,设计了具有热调控吸波特性的金属-介质-金属式的“三明治”式红外吸波结构。当VO2薄膜为底层的金属层时,低温时的吸波结构无明显吸收峰,且反射率都大于40%,高温时的吸波结构在3.2μm和7.5μm处存在驻波吸收峰和磁谐振吸收峰;当VO2薄膜为介质层时,低温时的吸波结构在9.9μm处存在一个较强的宽带吸收峰,高温时的吸波结构则在该波段表现出近似高反射的特性,且反射率都大于90%。(3)以双介质层的“三明治”红外吸波结构为研究对象,提出了基于驻波和磁谐振耦合机理的宽带红外吸波结构设计方法,并制备出了在中心波长8.32μm处具有2.9μm吸收带宽(吸收率大于80%)的热控制宽带红外吸波结构。这种方法对制备工艺要求简单,并且能够通过简单地调整结构参数来改变吸收峰的位置。(4)基于所设计的热控制智能红外吸波结构,制备了具有较高热稳定性和识别度的红外“水印”,在VO2的相变过渡态中(61~71?C),图形区域的辐射温度差仅为1.4?C(44.1~45.5?C),其平均发射率的变化范围为0.45~0.56;降温过程中,图形区域的辐射温度差仅为0.4?C(42.6~43?C),平均发射率的变化范围为0.4~0.51。而“水印”的非图形区域在升温和降温过程中的辐射温度变化范围都为21.3~21.9?C,其平均发射率约为0.04。
[Abstract]:In recent years, infrared absorbing structure has become a research hotspot in the field of artificial electromagnetic supermaterial due to its unique electromagnetic resonance characteristics. At the same time, with the rapid development of phase change material, it has been widely used in infrared absorbing structure, which not only has the functional characteristics of artificial electromagnetic supermaterial, but also becomes more intelligent. Its research value and application prospect are more and more broad. In this paper, the classical "sandwich" absorbing structure of metal, dielectric and metal is studied, and the VO2 film with thermal phase transition property is used as the metal layer and the dielectric layer, respectively. The dispersion characteristics of the relative dielectric constant of VO2 thin films in different states are studied. Based on this, an intelligent infrared absorbing structure with thermal control characteristics is designed and its working mechanism is analyzed and verified. In this paper, the main innovations and related research results are as follows: 1) the dispersion characteristics of phase change VO2 films in metal, semiconductor, phase transition and composite states are investigated. Through nonlinear fitting and effective medium theory, the relative permittivity and dispersion characteristics of VO2 thin films in various states are obtained. It is considered that the dispersion model used is not only simple in fitting method, but also accurate in fitting results. It is also suitable for composite materials with composite phase or impurity phase. The VO2 film is used as the metal layer and the dielectric layer of the absorbing structure, respectively. A kind of "sandwich" infrared absorbing structure with the characteristics of thermally controlled wave absorption is designed. When the VO2 thin film is the bottom metal layer, the absorption structure has no obvious absorption peak at low temperature, and the reflectivity is greater than 40. At high temperature, there are standing wave absorption peaks and magnetic resonance absorption peaks at 3.2 渭 m and 7.5 渭 m, and when the VO2 thin film is the dielectric layer, At low temperature, there exists a strong broadband absorption peak at 9.9 渭 m, while at high temperature, the absorption structure exhibits the characteristic of approximately high reflectance. And the reflectivity is greater than 90. 3) taking the "sandwich" infrared absorbing structure of the double dielectric layer as the research object, a broadband infrared absorbing structure design method based on the mechanism of standing wave and magnetic resonance coupling is proposed. At the center wavelength of 8.32 渭 m, the thermal controlled broadband infrared absorption structure with 2.9 渭 m absorption bandwidth (absorptivity greater than 80) has been prepared. This method is simple for the preparation process, and can change the position of absorption peak by simply adjusting the structure parameters.) based on the designed thermal control intelligent infrared absorbing structure, Infrared "watermark" with high thermal stability and recognition has been prepared. In the transition state of VO2, the radiative temperature difference in the phase transition state of VO2 is only 1.4? C ~ (1) C ~ (1) ~ (4) ~ (4) ~ (4) ~ (5) ~ (5) C ~ (1), its average emissivity varies from 0.45 to 0.56, and during the cooling process, the average emissivity of the watermark is 0.45 ~ 0.56. The radiative temperature difference in the figure region is only 0.4C ~ (2 +) ~ (42.6m) ~ (43) C ~ (-1), and the average emissivity is in the range of 0.4 ~ 0.51C ~ (-1). However, the range of radiation temperature in the non-graphic region of "watermark" during heating and cooling is 21.3O21.9 C, and its average emissivity is about 0.04.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB303

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