本文關鍵詞： 超常材料 近紅外微結構耦合器 聲聚焦透鏡 單向負折射　出處：《黑龍江大學》2015年碩士論文　論文類型：學位論文

【摘要】：Metamaterial是20世紀末興起的一種新型的人工結構性材料。其所具有的特異性結構賦予了該類型材料超乎尋常的物理性質,主要表現(xiàn)在其能對諸如電磁波、聲波等能量場的完美操控;相對于常規(guī)介質材料,該類型材料的另一個優(yōu)勢在于其具有亞波長尺寸的結構周期。因此,超材料的出現(xiàn)為結構微型化、功能超�；钠骷谱魈峁┝艘粋�可行的途徑。本文首先根據(jù)電磁超材料器件的典型設計理論-坐標變換理論,設計了一種近紅外光學微結構耦合器,并詳細論述了耦合器耦合特性和工作波長、組成耦合器基本單元的電磁參數(shù)、基本單元的數(shù)量以及耦合器尺寸之間的關系。理論結果表明,通過選定合適的耦合器基本單元,能夠實現(xiàn)耦合器效率高達100%全透射;而且,可以通過調節(jié)耦合器尺寸,使其滿足不同頻帶的完美透射的需求。其次,從理論方面入手,設計了一種聲學超材料聚焦透鏡。通過分析組成該聚焦透鏡的相位控制單元的聲場傳輸特性,選擇透射率高、相位控制精準的結構單元組成聲聚焦透鏡。仿真結果表明,在相控單元厚度及間距均實現(xiàn)了亞波長尺寸的前提下,上述聲聚焦透鏡在設計工作頻率4167Hz處成功實現(xiàn)了3.29dB增益效果。這對于減小傳統(tǒng)聲聚焦器件的尺寸,設計出能滿足要求的聲聚焦透鏡具有一定的指導意義。最后,基于等效介質理論,設計了一種聲學單向負折射棱鏡,并從實驗上對其效果進行驗證。實驗數(shù)據(jù)表明:在10KHz-20KHz的頻率范圍內,上述結構均能實現(xiàn)聲能流的單向負折射傳輸。上述設計改善了現(xiàn)有單向傳輸器件工作頻帶較窄的特性,在醫(yī)學超聲等需要聲能流進行特殊控制的領域具有潛在的應用價值。
[Abstract]:Metamaterial is a new type of artificial structural material which emerged at the end of 20th century. Its special structure endows this type of material with unusual physical properties, mainly because of its perfect manipulation of energy fields such as electromagnetic waves and sound waves. Another advantage of this type of material over conventional dielectric materials is that it has a structural period of subwavelength size. Therefore, the appearance of metamaterials is structural miniaturization. The fabrication of functional supernormal devices provides a feasible way. Firstly, according to the typical design theory of electromagnetic supermaterial devices-coordinate transformation theory, a near infrared optical microstructural coupler is designed. The coupling characteristics and working wavelength of coupler, the electromagnetic parameters of the basic unit of coupler, the number of basic elements and the relationship between the size of coupler are discussed in detail. The theoretical results show that the appropriate basic unit of coupler is selected. It can realize the efficiency of coupler up to 100% full transmission. Moreover, by adjusting the size of coupler, it can meet the requirements of perfect transmission in different frequency bands. Secondly, from the theoretical point of view, An acoustic metamaterial focusing lens is designed. By analyzing the sound field transmission characteristics of the phase control unit which is composed of the focusing lens, the sound focusing lens is composed of a structural unit with high transmittance and precise phase control. On the premise that the thickness and spacing of the phase control unit are subwavelength size, the sound focusing lens has achieved 3.29dB gain effect at the design frequency of 4167 Hz, which can reduce the size of the conventional acoustic focusing device. The design of an acoustic focusing lens that can meet the requirements is of certain guiding significance. Finally, based on the theory of equivalent medium, an acoustic one-way negative refraction prism is designed. The experimental data show that in the frequency range of 10kHz to 20kHz, the above structure can realize the unidirectional negative refraction transmission of sound energy flow, and the above design improves the narrower band characteristic of the existing unidirectional transmission devices. It has potential application value in fields such as medical ultrasound which need special control of acoustic energy flow.
【學位授予單位】：黑龍江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB39

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本文編號：1535623