A Geometrically-Appropriate Cavity Model for a Spherical Inverted-F Antenna (SIFA)

第３５卷第３期　２０１４年３月　通信学报　Ｊｏｕｍａｌ　ｏｎ　Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ　Ｖｂ１．３５　ＮＯ．３　Ｍａｒｃｈ　２０１４　

ｄｏｉ：１０．３９６９／ｊ．ｉｓｓｎ．１０００—４３６ｘ．２０１４．０３．００５　

基于Ｉｎｖｅｒｔｅｄ．Ｐａｒａｂｏｌｉｃ　分布的空间统计信道模型　

周杰　，一，徐冬冬　，　

（１．南京信息工程大学气象探测与信息处理重点实验室，江苏南京　菊池久和　，　

２１００４４；２．日本国立新泻大学工学部，新泻９５０—２１８１）　

摘要：针对在非均匀散射体分布下信号到达角度、到达时问以及多普勒效应等信道参数估计的复杂性，提出一　种合理的空间信道模型，并引入几何分割法导出基于散射体Ｉｎｖｅｒｔｅｄ—Ｐａｒａｂｏｌｉｃ分布的空间统计信道模型。模型能　

方便地估计室外宏小区和微小区移动通信环境下各种重要的空时信道参数，如ＡＯＡ、ＴＯＡ概率分布密度函数和　

多普勒功率谱以及信号的空一时相关性。数值结果与均匀散射体圆模型和高斯散射体圆模型对比表明本模型的信　

道参数估计结果符合理论和经验，且与实测结果吻合较好。在基站设计采用指向性天线时研究了移动台ＭＳ的多　

普勒效应，修正了Ｃｌａｒｋｅ　Ｕ．ｓｈａｐｅｄ经典模型，阐明了天线主瓣宽度２　、空间模型参数Ｄ／Ｒ和ＭＳ移动参数影响　

信道参数的机理。　

关键词：电波传播；空时信道模型；单反射圆模型／椭圆模型：到达角度；到达时间；多普勒效应　

中图分类号：ＴＮ９１１．６　文献标识码：Ａ　文章编号：１０００—４３６Ｘ（２０１４）０３—００３８—０９　

Ｇｅｏｍｅｔｒｉｃａｌ　ｓｔａｔｉｓｔｉｃａｌ　

Ｉｎｖｅｒｔｅｄ．．Ｐａｒａｂｏｌｉｃ　ｃｈａｎｎｅｌ　ｍｏｄｅｌ　ｗｉｔｈ　ａｎ　

ｓｐａｔｉａｌ　ｄｉｓｔｒｉｂｕｔｉｏｎ　

ＺＨＯＵ　Ｊｉｅ　，－，ＸＵ　Ｄｏｎｇ．ｄｏｎｇ　，ＨＩＳＡＫＡＺＵ　Ｋｉｋｕｃｈｉ　＇　

（１．ＣｏｌｌｅｇｅｏｆＥｌｅｃｔｒｏｎｉｃ＆ＩｎｆｏｒｍａｔｉｏｎＥｎｇｉｎｅｅｒｉｎｇ，ＮａｎｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＩｎｆｏｒｍａｔｉｏｎＳｃｉｅｎｃｅ　ａｎｄＴｅｃｈｎｏｌｏｇｙ，Ｎａｎｊｉｎｇ２１００４４，Ｃｈｉｎａ　２．Ｄｅｐａｒｔｍｅｎｔ　ｏｆＥｌｅｃｔｒｏｎｉｃ　ａｎｄ　Ｅｌｅｃｔｒｉｃａｌ　Ｅｎｇｉｎｅｅｒｉｎｇ，Ｎｉｉｇａｔａ　Ｕｎｉｖｅｒｓｉｔｙ，Ｎｉｉｇａｔａ　９５０—２１８１，Ｊａｐａｎ）　

Realization of subwavelength guiding utilizing coupled wedge plasmon polaritons in splitted groove waveguides Jian Pan1, Kaiting He1, Zhuo Chen1,*, and Zhenlin Wang1 1Department of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China *zchen@ Abstract: A detailed numerical study of propagation characteristics of a coupled wedge plasmon polariton (CWPP) in splitted groove waveguide (SGW) formed with two metal wedges is performed by using the finite element method (FEM). It is shown that the SGW structure could confine CWPP modes tightly to the nano-gap region between the wedge tips, operating in a much broad bandwidth. The effect of the glass substrate, wedge roundness, gap width, groove wedge angle, and groove depth are also investigated. Particularly, our SGWs are found to be quite robust against groove depth reduction, which could be beneficial to minimize the waveguide structure dimensions. Feasibility of using such SGWs for the design of efficient subwavelength plasmonic elements is also discussed on the nanoscale whispering gallery resonators as an example. ©2010 Optical Society of America OCIS codes: (240.6680) Surface plasmons; (230.7380) Waveguides, channeled; (250.5300) Photonic integrated circuits. References and links 1. H. Raether, Surface Plasmons on Smooth and Rough Surfaces and on Gratings, 1st ed. (Springer-Verlag, Berlin, 1988). 2. R. Zia, J. A. Schuller, A. Chandran, and M. L. Brongersma, “Plasmonics: the next chip-scale technology,” Mater. Today 9(7-8), 20–27 (2006). 3. T. W. Ebbesen, C. Genet, and S. I. Bozhevolnyi, “Surface-plasmon circuitry,” Phys. Today 61(5), 44–50 (2008). 4. P. Berini, “Plasmon-polariton waves guided by thin lossy metal films of finite width: Bound modes of symmetric structures,” Phys. Rev. B 61(15), 10484–10503 (2000). 5. T. Nikolajsen, K. Leosson, I. Salakhutdinov, and S. I. Bozhevolnyi, “Polymer-based surface-plasmon-polariton stripe waveguides at telecommunication wavelengths,” Appl. Phys. Lett. 82(5), 668–670 (2003). 6. B. Lamprecht, J. R. Krenn, G. Schider, H. Ditlbacher, M. Salerno, N. Felidj, A. Leitner, F. R. Aussenegg, and J. C. Weeber, “Surface plasmon propagation in microscale metal stripes,” Appl. Phys. Lett. 79(1), 51–53 (2001). 7. S. I. Bozhevolnyi, J. Erland, K. Leosson, P. M. W. Skovgaard, and J. M. Hvam, “Waveguiding in surface plasmon polariton band gap structures,” Phys. Rev. Lett. 86(14), 3008–3011 (2001). 8. S. A. Maier, P. G. Kik, H. A. Atwater, S. Meltzer, E. Harel, B. E. Koel, and A. A. G. Requicha, “Local detection of electromagnetic energy transport below the diffraction limit in metal nanoparticle plasmon waveguides,” Nat. Mater. 2(4), 229–232 (2003). 9. K. Tanaka, and M. Tanaka, “Simulations of nanometric optical circuits based on surface plasmon polariton gap waveguide,” Appl. Phys. Lett. 82(8), 1158–1160 (2003). 10. R. Zia, M. D. Selker, P. B. Catrysse, and M. L. Brongersma, “Geometries and materials for subwavelength surface plasmon modes,” J. Opt. Soc. Am. A 21(12), 2442–2446 (2004). 11. L. Liu, Z. Han, and S. He, “Novel surface plasmon waveguide for high integration,” Opt. Express 13(17), 6645–6650 (2005). 12. T. Holmgaard, Z. Chen, S. I. Bozhevolnyi, L. Markey, and A. Dereux, “Dielectric-loaded plasmonic waveguide-ring resonators,” Opt. Express 17(4), 2968–2975 (2009). 13. S. I. Bozhevolnyi, V. S. Volkov, E. Devaux, and T. W. Ebbesen, “Channel plasmon-polariton guiding by subwavelength metal grooves,” Phys. Rev. Lett. 95(4), 046802 (2005). 14. E. Moreno, S. G. Rodrigo, S. I. Bozhevolnyi, L. Martín-Moreno, and F. J. García-Vidal, “Guiding and focusing of electromagnetic fields with wedge plasmon polaritons,” Phys. Rev. Lett. 100(2), 023901 (2008). 15. S. I. Bozhevolnyi, V. S. Volkov, E. Devaux, J.-Y. Laluet, and T. W. Ebbesen, “Channel plasmon subwavelength waveguide components including interferometers and ring resonators,” Nature 440(7083), 508–511 (2006). 16. V. S. Volkov, S. I. Bozhevolnyi, E. Devaux, J.-Y. Laluet, and T. W. Ebbesen, “Wavelength selective nanophotonic components utilizing channel plasmon polaritons,” Nano Lett. 7(4), 880–884 (2007). #128883 - $15.00 USDReceived 26 May 2010; revised 26 Jun 2010; accepted 8 Jul 2010; published 23 Jul 2010(C) 2010 OSA2 August 2010 / Vol. 18, No. 16 / OPTICS EXPRESS 1672217. H. T. Miyazaki, and Y. Kurokawa, “Squeezing visible light waves into a 3-nm-thick and 55-nm-long plasmon cavity,” Phys. Rev. Lett. 96(9), 097401 (2006). 18. E. Moreno, F. J. García-Vidal, S. G. Rodrigo, L. Martín-Moreno, and S. I. Bozhevolnyi, “Channel plasmon-polaritons: modal shape, dispersion, and losses,” Opt. Lett. 31(23), 3447–3449 (2006). 19. J. Valentine, S. Zhang, T. Zentgraf, E. Ulin-Avila, D. A. Genov, G. Bartal, and X. Zhang, “Three-dimensional optical metamaterial with a negative refractive index,” Nature 455(7211), 376–379 (2008). 20. M. Haraguchi, D. F. P. Pile, T. Okamoto, M. Fukui, and D. K. Gramotnev, “New Plasmon Waveguides Composed of Twin Metal Wedges with a Nano Gap,” Opt. Rev. 13(4), 228–230 (2006). 21. D. F. P. Pile, D. K. Gramotnev, M. Haraguchi, T. Okamoto, and M. Fukui, “Numerical analysis of coupled wedge plasmons in a structure of two metal wedges separated by a gap,” J. Appl. Phys. 100(1), 013101 (2006). 22. A. Manjavacas, and F. J. García de Abajo, “Robust plasmon waveguides in strongly interacting nanowire arrays,” Nano Lett. 9(4), 1285–1289 (2009). 23. E. J. R. Vesseur, F. J. García de Abajo, and A. Polman, “Modal decomposition of surface--plasmon whispering gallery resonators,” Nano Lett. 9(9), 3147–3150 (2009). 24. COMSOL Multiphysics 3.3a. 25. A. Vial, A.-S. Grimault, D. Macias, D. Barchiesi, and M. L. de la Chapelle, “Improved analytical fit of gold dispersion: Application to the modeling of extinction spectra with a finite-difference time-domain method,” Phys. Rev. B 71(8), 085416 (2005). 26. J. A. Dionne, H. J. Lezec, and H. A. Atwater, “Highly confined photon transport in subwavelength metallic slot waveguides,” Nano Lett. 6(9), 1928–1932 (2006). 27. H. Choi, D. F. P. Pile, S. Nam, G. Bartal, and X. Zhang, “Compressing surface plasmons for nano-scale optical focusing,” Opt. Express 17(9), 7519–7524 (2009). 28. S. I. Bozhevolnyi, “Effective-index modeling of channel plasmon polaritons,” Opt. Express 14(20), 9467–9476 (2006). 29. M. Oxborrow, “Traceable 2-D Finite-Element Simulation of the Whispering-Gallery Modes of Axisymmetric Electromagnetic Resonators,” IEEE Trans. Microw. Theory Tech. 55(6), 1209–1218 (2007). 1. Introduction Surface plasmon polariton (SPP) is a fundamental electromagnetic excitation which may exist at the interface between metal and dielectric, with the fields decaying exponentially away from its maximum at the interface [1]. This inherently implies that SPPs can be laterally confined below the diffraction limit, and thus used as signal carriers to transport information in subwavelength waveguides [2]. A key issue in designing plasmonic waveguide geometries is to achieve a balance between modal confinement and propagation length [3]. Meanwhile, the convenience for technical realization should also be taken into account. Over the years, various plasmonic waveguide structures have been prototyped, including metallic stripes in symmetric [4,5] and asymmetric [6] environments, SPP band-gap structures [7], metallic nanoparticle chains [8], metal-insulator-metal (MIM) gap structures [9–11], dielectric-loaded SPP waveguides [12], V-shaped metal grooves [13], and Λ-shaped metal wedges [14], etc. Among aforementioned plasmonic waveguides, V-grooves engraved in a thick metal film supporting channel plasmon polartions (CPPs) have been demonstrated to show strong lateral confinement of the SPP fields at the bottom of grooves, simultaneously with low propagation losses at telecommunication wavelengths [13]. Furthermore, based on such kind of V-groove waveguide (VGW) structure, plasmonic functional devices such as ring resonators, Mach-Zehnder interferometers, and add-drop multiplexers, have been successfully realized [15, 16]. In contrast to the extreme plasmon confinement in narrow insulator films buried inside metal [17], VGW with a finite groove depth always involve electromagnetic fields extending significantly away from the groove bottom upon increasing the operating wavelength, and consequently producing a substantial degree of cross talk between neighboring waveguides, which thus limits the integration level and operation bandwidth of plasmonic circuits [18]. To improve the integration density of circuits, MIM gap structures have been attracting a great deal of attention due to its strong modal confinement. For example, Tanaka et al. simulated a SPP gap waveguide (SPGW) composed of a narrow gap region sitting in a wide gap region between two metallic plates, and showed that optical circuits based on SPGW could perform guiding, branching, and bending functions of optical waves in the nanometric device [9]. Liu et al. also proposed a “free-standing” MIM SPP waveguide formed by etching a small trench through a metallic thin film on a silica substrate and followed by coating an upper polymer cladding to construct a symmetric environment [11]. Note that in the previous studies on MIM gap SPP waveguides only rectangular gap structures are considered, in #128883 - $15.00 USDReceived 26 May 2010; revised 26 Jun 2010; accepted 8 Jul 2010; published 23 Jul 2010(C) 2010 OSA2 August 2010 / Vol. 18, No. 16 / OPTICS EXPRESS 16723

Effectofquenchhardeningonparticle-sizedependence

inmetalmatrixcompositesusingthestraingradient

theoryofplasticity

D.F.Caoa,b,∗,L.S.Liub,c,S.X.Lia,b

aDepartmentofMechanicalEngineering,UniversityofBristol,UnitedKingdombStateKeyLaboratoryofMaterialsSynthesisandProcessing,WuhanUniversityofTechnology,Wuhan,P.R.ChinacDepartmentofEngineeringStructureandMechanics,WuhanUniversityofTechnology,Wuhan,P.R.China

Abstract

Thestraingradienttheoriesofplasticityhavebeensuccessfullyusedtochar-

acterizethesize-dependentbehaviorofparticle-reinforcedmetal-matrixcom-

posites(PRMMCs),buttheygenerallyignorethepresenceofpre-existing

heterogeneouslydistributedthermalresidualstressesduetothequenchpro-

cessing.TheTaylor-basednonlocaltheory(TNT)ofplasticityinvolvingther-

malresidualstresses(TRSs)isimplementedintheframeworkofcontinuum

plasticity,inordertoinvestigatethesize-dependenceofaluminummatrix

第 21 卷 第 12 期

2023 年 12 月Vol.21，No.12Dec.，2023太赫兹科学与电子信息学报

Journal of Terahertz Science and Electronic Information Technology

InGaAs/InAlAs光电导太赫兹发射天线的制备与表征

陈益航1，杨延召2，张桂铭2，徐建星1，苏向斌1，王天放1，余红光1，

石建美1，吴斌2，杨成奥1，张宇1，徐应强1，倪海桥1，牛智川1

(1.中国科学院半导体研究所，北京 100083；2.中国电子科技集团公司 第四十一研究所，山东 青岛 266555)

摘要：光电导天线作为太赫兹时域光谱仪产生与探测太赫兹辐射的关键部件，具有重要的

科研与工业价值。本文采用分子束外延(MBE)方法制备InGaAs/InAlAs超晶格作为1 550 nm光电

导天线的光吸收材料，使用原子力显微镜、光致发光、高分辨X射线衍射等方式验证了材料的高

生长质量；通过优化制备条件得到了侧面平整的台面结构光电导天线。制备的光电导太赫兹发射

天线在太赫兹时域光谱系统中实现了4.5 THz的频谱宽度，动态范围为45 dB。

关键词：太赫兹时域光谱仪；光电导天线；分子束外延；InGaAs/InAlAs超晶格

中图分类号：TN405.98+.4 文献标志码：Adoi：10.11805/TKYDA2022204

Fabrication and characterization of InGaAs/InAlAs photoconductive

terahertz transmitting antenna

CHEN Yihang1，YANG Yanzhao2，ZHANG Guiming2，XU Jianxing1，SU Xiangbin1，WANG Tianfang1，

YU Hongguang1，SHI Jianmei1，WU Bin2，YANG Cheng'ao1，ZHANG Yu1，