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1.
L. Chen T. H. Kho A. T. Lin 《International Journal of Infrared and Millimeter Waves》1990,11(7):821-835
A general dispersion relation for the cyclotron autoresonance maser (CARM) that takes into account self-consistent couplings between TE, TM and ac space charge perturbations in a uniform planar waveguide is derived. The dispersion relation predicts enhanced growth rate due to ac space charge effects. Results from computer simulations of a planar CARM amplifier are presented to support this finding. 相似文献
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Pendergast K.D. Danley B.G. Temkin R.J. Wurtele J.S. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(2):122-128
A self-consistent, one-dimensional model of the cyclotron autoresonance maser (CARM) amplifier is developed, and numerical simulations based on this model are described. Detailed study results of the CARM gain and efficiency for a wide range of initial energy and velocity spreads are presented. The interaction efficiency is found to be substantially increased when the axial magnetic field is tapered. Efficiencies of greater than 41% are obtained for a 140-GHz CARM amplifier with a tapered axial magnetic field and a 700-kV 4.5-A electron beam with parallel velocity spreads of less than 1%. A discussion of the nonlinear bandwidth and interaction sensitivity to axial-field inhomogeneities is presented 相似文献
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优化设计了一种220 GHz的折叠波导慢波结构的尺寸,对其冷测特性如色散、耦合阻抗和衰减进行了分析。理论分析和软件仿真结果表明设计的折叠波导慢波结构在中心频率处具有较平缓的色散关系,较高的耦合阻抗和较低的电路衰减。互作用模拟表明,在电子注电压为20 kV,电流为10 mA时,27 mm(50个周期)的折叠波导慢波结构在220 GHz具有14.5 dB的增益,3 dB带宽为16.3 GHz(211.9~228.2 GHz)。 相似文献
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Parks P.B. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(2):223-227
Approximate analytic solutions for the resonant interaction of a relativistic electron beam interacting with a constant amplitude TEM wave, as in the cyclotron autoresonance maser (CARM) oscillator configuration, are presented. The approximation neglects force bunching relative to inertial bunching, which is usually valid for CARM parameter values of interest in many applications 相似文献
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为了有效分析模式竞争,建立了回旋自谐振脉塞(CARM)多模束波互作用自洽非线性理论模型,并具体模拟研究了工作模式为TM51、频率为0.35 THz的高阶横磁模CARM中大轨道相对论电子束与多电磁模式的互作用过程。模拟结果表明:与回旋管不同,THz频段CARM可以有效工作于高阶TM模式,且具有较高的输出功率和增益;通过对工作参数的优化,可使工作模式的功率增长具有绝对优势,而竞争模式得到有效抑制;高阶TM模式THz频段CARM的性能对工作参数的变化十分敏感,在参数设计过程中必须对其进行多模束波互作用模拟分析。 相似文献
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Hervé Gouraud Laurent Billonnet Pierre Faugeras Bernard Jarry 《Optics Communications》2006,265(2):506-512
The analysis of the influence of dispersion properties of the dispersive line used in a microwave photonic slicing filter is presented. We establish a general relation between both chromatic dispersion value and slope, allowing the optimization of the frequency response of the filter. Experimental validations are presented in good agreement with theoretical and numerically simulated results. Narrow bandwidth bandpass filter (<100 MHz) is achieved at the central frequency of 6.48 GHz, corresponding to the limit value in reference to the used broadband light source and fiber dispersion. 相似文献
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周期性结构是光学薄膜设计的基本物理模型,给出了反射区中心波长的一般性条件,研究了在膜层材料存在折射率色散情况下,等厚周期结构和非等厚周期结构的薄膜反射区中心波长与带宽特性.研究结果表明:在等厚和非等厚周期结构中,考虑膜层材料折射率色散与忽略色散情况相比,中心波长向长波方向移动,反射级次与相对波数的线性关系偏离;在薄膜光学厚度一定的非等厚周期结构中,高折射率层光学厚度大于低折射率层时,反射级次与相对波数的线性关系偏离度高;非等厚周期结构薄膜的带宽在低反射级次上小于等厚周期结构,同时膜层的色散对反射带宽影响不大. 相似文献
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多模梯度折射率塑料光纤带宽的分析 总被引:3,自引:3,他引:0
结合WKB法对多模梯度折射率塑料光纤(GI-POF)色散和带宽进行了综合分析,研究了在GI-POF中材料色散对带宽影响的程度和规律,给出较佳折射率指数(g)的范围,并说明实测带宽高于理论带宽的原因. 相似文献
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The spectral bandwidth of three-wave-mixing optical parametric amplification has been investigated. A general mathematical model for evaluating the spectral bandwidth of optical parametric amplification is developed with parametric bandwidth and gain bandwidth via three-wave noncollinear interactions. The spectral bandwidth is determined by expanding the wave-vector mismatch in a Taylor series and retaining terms through second order. The model takes into account the effects of crystal length, noncollinear angle, group velocity, group-velocity dispersion and gain coefficient. The relation between parametric bandwidth and gain bandwidth is clearly defined. The model is applied to a BBO OPA, a LBO OPA and a CLBO OPA. PACS 42.65.Yj; 42.65.Lm; 42.65.Ky; 42.60.By 相似文献
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Yubin Gong Yanyu Wei Wenxiang Wang Shenggang Liu 《International Journal of Infrared and Millimeter Waves》1997,18(11):2205-2217
The ridge loaded ring-plane traveling wave tube can provide high output power in a relatively broader bandwidth. The dispersion
relation for the interaction between the electron beam and the symmetrical mode propagating in this slow wave circuit is obtained,
by means of the Variational method. The method to calculate the arbitrary order Bessel function with complex argument is discussed.
The three dimensional trajectory graph of the Bessel function with complex argument is plotted. The instantaneous operating
bandwidth can be estimated in terms of the relation between of the gain and frequency. 相似文献
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Wang J.G. Gilgenbach R.M. Choi J.J. Outten C.A. Spencer T.A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1989,17(6):906-908
The authors report experimental observations of high-power microwave emission from both the high-frequency cyclotron autoresonance maser (CARM) oscillation and the low-frequency gyrotron interaction. High-power (3-10 MW) microwave emission is attributed to the CARM mechanism, which is magnetically tunable through discrete axial cavity modes from 15 through 16.7 GHz. For the same experimental parameters, megawatt-level microwave emission is observed, which is magnetically tunable from 10 through 14 GHz, indicating low-frequency gyrotron oscillation. High-frequency microwave pulse-lengths of up to 0.2 μs have been generated, which is a factor of five greater than those achieved in previous CARM experiments 相似文献
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V. L. Bratman G. G. Denisov M. M. Ofitserov S. V. Samsonov O. V. Arkhipov V. I. Kazacha A. K. Krasnykh E. A. Perelstein A. V. Zamrij 《International Journal of Infrared and Millimeter Waves》1992,13(12):1857-1873
An LIA-unit with explosive emission injector was used as a basis for CARM with high Doppler frequency up-conversion when the wave frequency is 7 to 9 times the cyclotron frequency of electrons. Using a high-selectivity Bragg resonator as an electrodynamic system of CARM we investigated two regimes having essentially different properties: the dispersion characteristics of the electron beam and the wave either intersected or were tangential to one another. In the first case, the radiation power amounted to 50 MW at the wavelength of 4.4 mm with efficiency 8%. The efficiency significantly smaller than the design value was evidently caused by a high level of parasitic superluminiscence of the beam. In the second regime of operation at 6 mm, the radiation power was 30 MW with a low level of parasitic superluminiscence and efficiency 10% which was close to the calculated value. 相似文献
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Pulse spreading due to the dispersion causes the overlapping of the transmitted pulses at the receiver end known as inter symbol interference (ISI). The ISI thus limits transmission of high speed data. We are living in the age of bandwidth hungry and high speed applications, for which optical networks form the most important part because of its high bandwidth. In optical networks chromatic dispersion (CD) is one of the main obstacle in high speed transmission. Hence this CD is compensated by various approaches throughout the transmission system. A review of all the main approaches is presented in this paper. Characterization of fiber Bragg grating for dispersion compensation is done using the reflection spectrum and group delay response analysis. 相似文献
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表面磁等离子体(surfacemagnetoplasmons,SMPs)是一种在电介质和偏置磁场作用下磁光材料界面处传播的近场电磁波.其独特的非互易传播特性引起了大量科研工作的关注,但在具体的波导结构设计上仍存在很多问题.本文研究了一种银-硅-磁光材料的3层平面波导结构,SMPs在磁光材料和硅的界面处传播,发现在特定的频率范围内,SMPs的基模及高阶模式均具有正向或反向的单向传播特性.分别计算了旋磁与旋电材料平面波导的色散方程,研究了硅层厚度与外加磁场对能带结构及SMPs单向传播区域的影响,发现无论是旋磁或旋电材料的结构,硅层厚度的增加使高阶模式使高阶模式出现在更低的频率位置,使单向传输带宽变小甚至消失,外加磁场的变大使磁光材料的能带结构频率增大的同时带隙中也引入了高阶模式.计算了2种磁光材料平面波导的正向和反向的单向传播带宽宽度,发现旋磁材料YIG的单向SMPs模式出现在GHz波段,最大单向带宽可达到2.45 GHz;旋电材料InSb的单向SMPs模式出现在THz波段,最大单向带宽达到3.9 THz. 相似文献
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G. Singh M. V. Kartikeyan G. S. Park 《International Journal of Infrared and Millimeter Waves》2006,27(3):333-342
Theoretical investigation of the peak-gain and 3-dB bandwidth of the vane-loaded gyro-traveling wave tube (gyro-TWT) amplifier
in the small-orbit TE01 waveguide mode configuration at 35 GHz has been presented. The vane-loaded gyro-TWT enjoys higher gain and bandwidth compared
to that of the smooth-wall device. In the analysis, the azimuthal harmonic effects generated due to the angular periodicity
of vanes in the wedge-shaped metal vane-loaded cylindrical waveguide interaction structure have been taken into account in
the cold (beam-absent) dispersion relation only. 相似文献