【摘要】：電磁波傳播通常是互易的。但是在磁光介質(zhì)和旋磁介質(zhì)中,電磁波的傳播可以是非互易的。這個非互易性是通信系統(tǒng)中一些重要器件的基礎(chǔ),例如隔離器和環(huán)形器。最近,人們發(fā)現(xiàn)在磁光介質(zhì)和旋磁介質(zhì)的表面,電磁波甚至可以單向地傳播。這個獨特的性質(zhì)提供給我們一個獨特的系統(tǒng)去研究最基本的電磁波傳播與耦合的問題。這篇博士論文的目標(biāo)就是揭示非互易電磁表面波的傳播與耦合的基本性質(zhì),并用這些性質(zhì)去設(shè)計新器件。我們在第一章簡要介紹了背景。然后,在第二章我們給出了電磁波非互易性的概念,討論了最主要發(fā)展的計算方法,針對旋磁光子晶體的平面波展開法,并介紹了能帶拓?fù)鋽?shù)—陳省身數(shù),同時介紹了微波旋磁介質(zhì)鐵氧體的材料模型。第三章,我們首次證明了,在外加磁場下,在空氣中的旋磁光子晶體平板的邊緣可以支持單向電磁波。此外加磁場打破了結(jié)構(gòu)的時間反演對稱性,打開原來的簡并點,創(chuàng)造了新的禁帶。由于水平向的禁帶效應(yīng)及垂直向的介電常數(shù)差,使得單向電磁波可以束縛在結(jié)構(gòu)邊緣。然后,我們研究了兩個單向波導(dǎo)間的耦合。我們發(fā)現(xiàn)當(dāng)兩波導(dǎo)中的模式傳播方向相同時,他們間可存在正向耦合。當(dāng)兩波導(dǎo)中的模式傳播方向相反時,他們間可以在傳播常數(shù)很接近的窄帶寬里發(fā)生反向耦合。這個反向耦合的效應(yīng)與‘"trapped rainbo w"概念相關(guān)。在第四章,我們討論了“trapped rainbow"的概念。它試圖將不同頻率的電磁波永久地停駐在不同位置。前人提出的結(jié)構(gòu),由于前向模式和后向模式間的反向耦合,所有的入射波都被反射了,而非停駐在特定位置,它們均不能真正實現(xiàn)‘"trapped rainbow"效應(yīng)。我們提出采用梯度磁場下非互易波導(dǎo)來克服這個根本性難點,在微波段實現(xiàn)真正的“trapped rainbow"式電磁波存儲。我們通過色散關(guān)系揭示了其背后的物理原理,并通過頻域和時域的仿真證明了電磁波停駐的效應(yīng),并且發(fā)現(xiàn)在臨界位置附件,電磁場得到增強,電磁’波脈沖也可以停駐較長時間。而且這些效應(yīng)在非互易波導(dǎo)中對障礙物具有魯棒性。在第五章,我們首次提出單向腔的概念。在太赫茲頻段,單向腔可由表面磁等離子體構(gòu)成。我們發(fā)現(xiàn)外加磁場可以使得腔中的順時針模式和逆時針模式完全分開在兩個不同的頻率范圍。這為我們在單向波的方向和頻率范圍上提供了更多的選擇。我們也對單向腔與波導(dǎo)間的耦合進(jìn)行了研究,并基于此設(shè)計了一個四端口環(huán)形器。最后,在第六章,我們做出結(jié)論,并討論了未來研究的方向。
[Abstract]:Electromagnetic wave propagation is usually reciprocal. However, the propagation of electromagnetic wave can be non-reciprocal in magneto-optic medium and gyromagnetic medium. This non-reciprocity is the basis of some important devices in communication systems, such as isolators and annulators. Recently, it has been found that electromagnetic waves can even propagate in one direction on the surface of magneto-optic and gyromagnetic media. This unique property provides us with a unique system to study the most fundamental problem of electromagnetic wave propagation and coupling. The purpose of this doctoral thesis is to reveal the basic properties of the propagation and coupling of non-reciprocal electromagnetic surface waves and to design new devices with these properties. In the first chapter, we briefly introduce the background. Then, in the second chapter, we give the concept of non-reciprocity of electromagnetic wave, discuss the most developed calculation method, and introduce the topological number of energy band-Shiing-Shen Chern number for the plane wave expansion method of gyromagnetic photonic crystal. At the same time, the material model of microwave magnetic medium ferrite is introduced. In chapter 3, we prove for the first time that the edge of a plate of magnetomagnetic photonic crystals in air can support unidirectional electromagnetic waves under an external magnetic field. In addition, the magnetic field breaks the time inversion symmetry of the structure, opens the original degenerate point, and creates a new forbidden band. Because of the horizontal bandgap effect and the permittivity difference in the vertical direction, the unidirectional electromagnetic wave can be bound to the edge of the structure. Then, we study the coupling between two unidirectional waveguides. We find that there is a positive coupling between the two waveguides when the modes propagate in the same direction. When the modes in the two waveguides propagate in the opposite direction, they can be coupled in a narrow bandwidth where the propagation constant is very close. This reverse coupling effect is related to the 'trapped rainbo w' concept. In Chapter 4, we discuss the concept of "trapped rainbow". It tries to stop electromagnetic waves of different frequencies permanently in different places. Because of the backward coupling between the forward mode and the backward mode, all incident waves are reflected instead of stopping at a specific position, so they can not really realize the 'trapped rainbow' effect. We propose to use nonreciprocal waveguides in gradient magnetic field to overcome this fundamental difficulty and realize real "trapped rainbow" electromagnetic wave storage in microwave field. We reveal the physical principle behind it by dispersion relation, prove the effect of electromagnetic wave stopping by simulation in frequency domain and time domain, and find that the electromagnetic field is enhanced at the critical position. Electromagnetic'- wave pulses can also stay for longer periods of time. Moreover, these effects are robust to obstacles in non-reciprocal waveguides. In the fifth chapter, we propose the concept of unidirectional cavity for the first time. At terahertz, a unidirectional cavity can be made up of a surface magnetic plasma. We find that the applied magnetic field can separate the clockwise mode and the counterclockwise mode completely in two different frequency ranges. This provides us with more choices in the direction and frequency range of unidirectional waves. We also study the coupling between the unidirectional cavity and the waveguide, and design a four-port loop based on this. Finally, in chapter 6, we draw a conclusion and discuss the direction of future research.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：O441

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 汪學(xué)海;;求解二階橢圓型偏微分方程的雙重互易雜交徑向邊界點法[J];長江大學(xué)學(xué)報(自然科學(xué)版)理工卷;2010年03期

2 李小文,王錦地,Alan H.Strahler;再論互易原理在二向性反射研究中的適用性[J];自然科學(xué)進(jìn)展;1999年S1期

3 樊志華;;雙互易雜交邊界點法參數(shù)及域內(nèi)節(jié)點分布[J];浙江大學(xué)學(xué)報(工學(xué)版);2011年07期

4 司馬玉洲;朱宏平;苗雨;;雙互易雜交邊界點法求解工程瞬態(tài)渦流問題[J];華中科技大學(xué)學(xué)報(自然科學(xué)版);2008年12期

5 潘志棟;;互易雙口的Pi形等效電路仿真[J];實驗室科學(xué);2013年06期

6 梁昌洪;陳曦;;電磁互易對稱性和無耗對稱性[J];電氣電子教學(xué)學(xué)報;2009年04期

7 姚保安;經(jīng)嘉云;徐宗海;張春生;;柯達(dá)103a-O底片的低照度互易率失效[J];中國科學(xué)院上海天文臺年刊;1985年00期

8 奚壽根;線性互易代數(shù)網(wǎng)絡(luò)的自然優(yōu)化分布的探索[J];蘇州絲綢工學(xué)院學(xué)報;1995年04期

9 梁昌洪，，崔鐵軍，李潤旗;非互易媒質(zhì)的本征導(dǎo)磁率和本征波[J];應(yīng)用科學(xué)學(xué)報;1994年01期

10 ;[J];;年期

相關(guān)會議論文 前2條

1 徐榮武;何琳;孫紅靈;程果;龐業(yè)珍;;雙層柱殼結(jié)構(gòu)水下互易實驗研究[A];第十四屆船舶水下噪聲學(xué)術(shù)討論會論文集[C];2013年

2 何龍標(biāo);牛鋒;許歡;鐘波;陳劍林;;互易法實現(xiàn)2Hz-20Hz聲壓靈敏度的高精度校準(zhǔn)[A];中國聲學(xué)學(xué)會2009年青年學(xué)術(shù)會議[CYCA’09]論文集[C];2009年

相關(guān)博士學(xué)位論文 前1條

1 劉珂鑫;論非互易電磁表面波的傳輸及耦合[D];浙江大學(xué);2016年

相關(guān)碩士學(xué)位論文 前1條

1 丁學(xué)文;互易毒品行為的刑法性質(zhì)研究[D];華東政法大學(xué);2016年

本文編號：2327142