【摘要】：超材料作為一種人工復(fù)合結(jié)構(gòu)或復(fù)合材料,具有自然界中存在的材料所不具備的某些特殊電磁性質(zhì),如負(fù)折射率、負(fù)群速度等,它在超分辨率成像、光學(xué)隱身、新型太陽能電池等領(lǐng)域具有重要的應(yīng)用前景。超材料吸波器作為超材料的一個重要分支,最近近幾年發(fā)展迅速,得到越來越多的關(guān)注。通過合理設(shè)計超材料的幾何結(jié)構(gòu),使超材料吸波結(jié)構(gòu)的表面阻抗與自由空間阻抗相匹配,可以實現(xiàn)對特定頻段電磁波的完美吸收。超材料完美吸波器可以被應(yīng)用于太赫茲成像,熱輻射儀,有毒物質(zhì)檢測等諸多領(lǐng)域。本文主要應(yīng)用計算機模擬和理論分析相結(jié)合的方法,對單頻、多頻超材料吸波器波段的吸收機制進(jìn)行了系統(tǒng)研究,得到了幾何參數(shù)和材料電磁參數(shù)對吸收率的影響規(guī)律�；陔姶挪ㄎ绽碚摵偷刃浇槔碚摰然纠碚�,研究了金屬方形薄片超材料吸收器在中紅外波段的吸收特性,通過調(diào)節(jié)其幾何尺寸,能夠?qū)崿F(xiàn)單頻完美吸收。結(jié)合等效電路模型分析該結(jié)構(gòu)的諧振頻率隨幾何參數(shù)的變化,并與仿真結(jié)果進(jìn)行了比較。通過數(shù)值仿真計算的諧振頻率和吸收率隨幾何參數(shù)的變化規(guī)律與通過等效電路模型推導(dǎo)的變化規(guī)律基本一致。通過分析超材料吸波器中電場模的分布解釋其物理機制。研究了一種基于電諧振器結(jié)構(gòu)的超材料吸波器的吸收特性,該吸收器在太赫茲波段可實現(xiàn)多頻、偏振無關(guān)的、寬角度完美吸收。通過改變其幾何參數(shù),實現(xiàn)了該結(jié)構(gòu)在中紅外波段的多頻完美吸收。并結(jié)合其電場模分布、能量損失密度分析其吸波機理。設(shè)計了一種多頻超材料吸波器,該結(jié)構(gòu)由一個電諧振器和金屬基板組成,能在12-24 THz的中紅外波段產(chǎn)生兩個大于90%的吸收峰,通過分析其電場模的分布,解釋其吸波機理。通過S參數(shù)反演法提取其等效參數(shù),計算出其波阻抗。
[Abstract]:As a kind of artificial composite structure or composite material, metamaterials have some special electromagnetic properties, such as negative refractive index, negative group velocity and so on, which are not existed in nature. New solar cells and other fields have important application prospects. As an important branch of metamaterials, metamaterial absorbers have been developed rapidly in recent years and received more and more attention. By reasonably designing the geometrical structure of the supermaterial, the surface impedance of the supermaterial absorbing structure can be matched with the free space impedance, and the perfect absorption of the electromagnetic wave can be realized in the specific frequency band. Metamaterial perfect absorbers can be used in terahertz imaging, thermal radiometer, toxic substances detection and many other fields. In this paper, the absorption mechanism of single-frequency and multi-frequency supermaterial absorbers is systematically studied by means of computer simulation and theoretical analysis, and the influence of geometric and electromagnetic parameters on absorptivity is obtained. Based on the theory of electromagnetic wave absorption and equivalent medium theory, the absorption characteristics of metal square sheet supermaterial absorber in the mid-infrared band are studied. By adjusting its geometric size, the perfect absorption of single frequency can be realized. Based on the equivalent circuit model, the variation of resonant frequency with geometric parameters is analyzed and compared with the simulation results. The variation of resonance frequency and absorptivity with geometric parameters calculated by numerical simulation is basically consistent with that derived from equivalent circuit model. The physical mechanism is explained by analyzing the distribution of electric field modes in metamaterial absorbers. The absorption characteristics of a metamaterial absorber based on the structure of an electric resonator are studied. The absorber can achieve multi-frequency polarization-independent wide-angle perfect absorption in terahertz band. By changing its geometric parameters, the multi-frequency perfect absorption of the structure in the mid-infrared band is realized. The wave absorption mechanism is analyzed by combining the electric field mode distribution and energy loss density. A multi-frequency supermaterial absorber is designed. The structure consists of an electric resonator and a metal substrate. It can produce two absorption peaks of more than 90% in the mid-infrared band of 12-24 THz. The wave absorption mechanism is explained by analyzing the distribution of the electric field modes. The equivalent parameters are extracted by S-parameter inversion method, and the wave impedance is calculated.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB33

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 顧超;屈紹波;裴志斌;徐卓;劉嘉;顧巍;;Multiband terahertz metamaterial absorber[J];Chinese Physics B;2011年01期

，

本文編號：2225506