本文選題：旋磁光子晶體 + 磁致能帶分裂　； 參考：《深圳大學(xué)》2017年碩士論文

【摘要】：隔離器一般是一種二端口無源器件,只允許信號(hào)單向通過。隔離器在保持信號(hào)源的穩(wěn)定性、減小傳輸過程中的噪聲干擾等方面應(yīng)用廣泛。傳統(tǒng)微波隔離器的隔離度一般在20—30dB之間。微波在波導(dǎo)中傳輸時(shí),存在著類量子霍爾手性邊緣態(tài)。本文中,我們用COMSOL軟件仿真了由磁性光子晶體構(gòu)成波導(dǎo)邊緣時(shí)微波的單向傳輸特性。應(yīng)用這種單向傳輸特性,隔離器的隔離度將會(huì)提高。在文獻(xiàn)[61]結(jié)構(gòu)基礎(chǔ)上,我們改進(jìn)了隔離器結(jié)構(gòu)。改變所加磁場(chǎng)的特性時(shí),隔離器的隔離效果會(huì)更好。同時(shí)模擬傳輸還證實(shí)了微波在波導(dǎo)中處于手性邊緣態(tài)時(shí)會(huì)單向傳輸,且有障礙物繞射特性。這對(duì)于隔離器的設(shè)計(jì)、制造和使用非常重要。我們運(yùn)用平面波展開法、時(shí)域有限差分法、多重散射法和有限元法等計(jì)算和分析了光子晶體的能帶結(jié)構(gòu)。在無外加磁場(chǎng)條件下,磁性光子晶體的相鄰能帶存在著一些簡(jiǎn)并點(diǎn);在外加磁場(chǎng)條件下,這些簡(jiǎn)并點(diǎn)被打破,這是一種磁致能帶分裂現(xiàn)象。在這些分裂的能帶的邊緣,非互易性的傳輸模式出現(xiàn),這是手性邊緣態(tài)出現(xiàn)的根本原因。預(yù)先設(shè)定光子晶體的晶格常數(shù)為1.33厘米,通過對(duì)介質(zhì)柱的半徑和波導(dǎo)的寬度的參數(shù)掃描,我們確定了隔離器結(jié)構(gòu)的相關(guān)參數(shù)。最后,我們?cè)O(shè)計(jì)了三種不同結(jié)構(gòu)、工作頻率在微波波段的隔離器。二級(jí)級(jí)聯(lián)的隔離器的工作頻率在14.2—14.8 GHz,最大隔離度能達(dá)到30dB;三級(jí)級(jí)聯(lián)的隔離器,工作頻率在13.7—14.7GHz,它在整個(gè)工作頻帶都具有極高的隔離度,最大時(shí)能接近150dB。針對(duì)光子晶體系統(tǒng)集成化的發(fā)展趨勢(shì),我們也初步設(shè)計(jì)了一種多端口光子晶體隔離器。這在家庭網(wǎng)絡(luò)中對(duì)信號(hào)源的分配以及相關(guān)互不干擾的應(yīng)用中,作用重要。
[Abstract]:Isolators are generally two-port passive devices that allow only one-way signal to pass through.Isolators are widely used in maintaining the stability of signal sources and reducing noise interference during transmission.The isolation of traditional microwave isolator is generally between 20-30dB.When the microwave propagates in the waveguide, there is a quantum Hall chiral edge state.In this paper, we use COMSOL software to simulate the unidirectional propagation of microwave when the waveguide edge is composed of magnetic photonic crystals.With this unidirectional transmission feature, the isolation of the isolator will be improved.Based on the [61] structure, we have improved the isolator structure.The isolation effect of the isolator is better when the magnetic field is changed.At the same time, it is proved that the microwave propagates in one direction in chiral edge state and has the characteristic of obstacle diffraction.This is important for the design, manufacture and use of isolators.The band structure of photonic crystals is calculated and analyzed by plane wave expansion method, finite difference time-domain method, multi-scattering method and finite element method.In the absence of an external magnetic field, there are some degenerate points in the adjacent band of the magnetic photonic crystal, and these degenerate points are broken under the condition of the external magnetic field, which is a phenomenon of the splitting of the band.At the edge of these split bands, non-reciprocal transport modes appear, which is the root cause of chiral edge states.The lattice constant of the photonic crystal is 1.33 cm. By scanning the radius of the dielectric column and the width of the waveguide, we determine the relative parameters of the isolator structure.Finally, we designed three different structures, operating frequency in the microwave band isolator.The operating frequency of the two-stage cascade isolator is 14.2-14.8 GHz, the maximum isolation degree can reach 30 dB, and the three-stage cascade isolator has a working frequency of 13.7-14.7 GHz. It has a very high isolation degree in the whole operating band, and the maximum isolation degree is close to 150 dB.In view of the development trend of photonic crystal system integration, we also design a multiport photonic crystal isolator.This plays an important role in the allocation of signal sources and the application of correlation noninterference in home networks.
【學(xué)位授予單位】：深圳大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN62;O734

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 王振力;郭慶功;;高性能X波段鐵氧體隔離器設(shè)計(jì)[J];無線電工程;2016年06期

2 岳峰;;邊導(dǎo)模隔離器的設(shè)計(jì)和研究[J];微波學(xué)報(bào);2012年S2期

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本文編號(hào)：1733594