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71.
72.
基于高品质因子微谐振腔的参量四波混频实现光学频率梳是一种新的频率梳实现方法,拓展了传统固体及非线性光纤飞秒激光器等光频梳的应用范围,在精密频率标定、天文光谱校准、任意波形产生、光学存储和孤子传输、片上通信用光源等方面具有较高的优势。本文简要总结、评述了几种主要的光频梳动力学分析模型及数值方法,以及这些不同方法的内在联系。基于描述光频梳动态行为的非线性Lugiato-Lefever方程分析了可能存在的动力学过程,并据此对不同特点光频梳进行了分类。通过设计反馈结构理论上研究了正常色散微腔和反常色散微腔的光梳特点,探讨了作为片上光互连用多波长光源应满足的条件及可能的实现途径。 相似文献
73.
《Organic Electronics》2014,15(9):1923-1927
We report on thermally activated whispering gallery laser modes of a solution of MEH-PPV conjugated polymer supported by a silica optical fiber. The viscosity of the polymer solution gives place to a thin shell of the gain solution around the fiber driven by capillary action. Whispering gallery modes (WGMs) are thermally induced by a decrease in the refractive index of the polymer solution under intense optical pumping. The laser emission is produced because the evanescent waves of the WGMs couple the surrounding gain medium. These results support the use of conjugated polymers in optofluidic laser systems and highlight the importance of physicochemical properties, such as viscosity and optically induced heating, on the performance of the devices. 相似文献
74.
A Q‐band pHEMT image‐rejection low‐noise amplifier (IR‐LNA) is presented using inter‐stage tunable resonators. The inter‐stage L‐C resonators can maximize an image rejection by functioning as inter‐stage matching circuits at an operating frequency (FOP) and short circuits at an image frequency (FIM). In addition, it also brings more wideband image rejection than conventional notch filters. Moreover, tunable varactors in L‐C resonators not only compensate for the mismatch of an image frequency induced by the process variation or model error but can also change the image frequency according to a required RF frequency. The implemented pHEMT IR‐LNA shows 54.3 dB maximum image rejection ratio (IRR). By changing the varactor bias, the image frequency shifts from 27 GHz to 37 GHz with over 40 dB IRR, a 19.1 dB to 17.6 dB peak gain, and 3.2 dB to 4.3 dB noise figure. To the best of the authors' knowledge, it shows the highest IRR and FIM/FOP of the reported millimeter/quasi‐millimeter wave IR‐LNAs. 相似文献
75.
Compact multi‐band bandpass filters using quad‐mode stub‐loaded resonators are proposed in this letter. Firstly, a novel approach about the mode‐splitting characteristics of the quadruple‐mode resonator is investigated, which can provide dual‐band behavior. Secondly, a quad‐band filter is proposed and designed by cascading two quadruple‐mode resonators; the upper one operates at 1.8/2.4 GHz (GSM‐ and WiMax‐band) and the lower one at 1.57/2.1 GHz (GPS‐ and WCDMA‐band). Finally, the proposed filters have been fabricated. Respectable agreement between simulation and measurement verifies the validity of this design methodology. 相似文献
76.
Xavier Boulanger Nicolas Jeannin Laurent Féral Laurent Castanet Frédéric Lacoste Françoise Carvalho 《International Journal of Satellite Communications and Networking》2014,32(5):423-441
This set of two companion papers aims at providing a model for the inter‐annual variability of earth‐space propagation statistics and for the inherent risk and CIs. In part I, it was proposed to model the yearly variance σ² of empirical complementary CDFs so that where is the variance of estimation, the inter‐annual climatic variance and p the long‐term probability. Particularly, an analytical formulation of was derived and parameterized from synthetic rain attenuation data. Considering the statistical framework developed in part I, this part II is specifically devoted to the parameterization of the variance of estimation from experimental data of rain attenuation and rainfall rate. Then, a methodology to model and parameterize worldwide the inter‐annual climatic variance is presented. The model of yearly variance of the empirical complementary CDFs is finally compared against yearly experimental variances derived from data collected worldwide. The knowledge of this variability is very useful for system design as it allows the risk on a required availability and associated with a given propagation margin to be quantified. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
77.
《AEUE-International Journal of Electronics and Communications》2014,68(7):658-660
A substrate integrated waveguide (SIW) loaded by three-dimensional embedded split ring resonators (3-DESRRs) is discussed theoretically and experimentally. The 3-DESRR structure which has proved to be an alternative magnetic metamaterial resonator for SIW structures is able to provide negative transversal permeability if excited properly. The 3-DESRR loaded SIW shows a bandpass-like response as an effect of loading the 3-DESRRs in the SIW. The lower and upper band edges of the resulting transmission line (TL) are determined by the SIW cutoff (fc) and the resonance frequency of the 3-DESRRs, respectively. Finally, a prototype of the proposed 3-DESRR loaded SIW TL is fabricated and tested. The measured results are in good agreement with those obtained by theory and simulation. 相似文献
78.
无人机在丘陵地带做低空飞行任务时,需要准确的对地高度信息才能保障无人机的安全飞行。本文研究了基于互补滤波网络的高度信息融合技术,针对气压高和无线电高的误差特性,分析了互补滤波的理论依据,设计了互补滤波网络的时间常数,给出了离散域内互补滤波器的算法。最后针对某无人机进行了非线性仿真和试飞验证,结果表明设计的滤波器满足无人机在丘陵地带的低空飞行要求。 相似文献
79.
Bent互补函数族的性质和构造方法 总被引:13,自引:1,他引:12
本文提出了Bent互补函数族的概念,研究了Bent互补函数族的性质和构造方法。 相似文献
80.
R. Craigen 《Journal of Combinatorial Theory, Series A》2006,113(6):952-965
In [R. Craigen, C. Koukouvinos, A theory of ternary complementary pairs, J. Combin. Theory Ser. A 96 (2001) 358-375], we proposed a systematic approach to the theory of ternary complementary pairs (TCPs) and showed how all pairs known then could be constructed using a single elementary product, the natural equivalence relations, and a handful of pairs which we called primitive. We also introduced more new primitive pairs than could be inferred previously, concluding with some conjectures reflecting the patterns that were beginning to arise in light of the new approach.In this paper we take what appears to be the natural next step, by investigating these patterns among those lengths and weights that are within easy computational distance from the last length considered therein, length 14. We give complete results up to length 21, and partial results up to length 28. (Ironically, although we proceed analytically by weight first then length, for computational reasons we are bound, in this empirical investigation, to proceed according to length first.)Thus we provide support for the previous conjectures, and shed enough new light to speculate further as to the likely ultimate shape of the theory. Since short term work on TCPs will require massive acquisition of data about small pairs, we also discuss affixes—a computational strategy that arose out of the investigations culminating in this article. 相似文献