共查询到18条相似文献,搜索用时 203 毫秒
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本文介绍了中科院电子所Ku波段150 W连续波空间行波管的设计、模拟和测试结果。该行波管采用双阳极电子枪、螺旋线跳渐变慢波结构、非轴对称四级降压收集极、辐冷型散热器。动态通过率在98.5%以上,在12.25~12.75 GHz范围内输出功率大于154 W,效率大于62%,增益大于51.8 dB,饱和点非线性相移小于46.65°,AM/PM变换系数小于4.31°/dB。环境试验结果表明行波管结构设计符合卫星力学环境条件,热设计符合空间环境试验条件。 相似文献
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给出了四次谐波产生的多级级联二阶非线性耦合方程基波相移的解析表达式,该方法实现了利用两个相位失配因子对基波相移的控制。对由该效应产生基波相移与传统级联二阶非线性产生的基波非线性相移进行了对比。 相似文献
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为了研究模拟光信号在半导体光放大器中的交叉相位调制特性,以正弦波和三角波两种模拟光信号为例,采用数值计算的方法,详细分析了交叉相位调制过程中模拟信号的增益、非线性相移差和啁啾。结果表明,当信号光和控制光之间采用帧同步方式时,信号光脉冲各点的增益及增益差出现波动,非线性相移差将围绕理想值π出现不同程度的偏离;采用比特同步方式可使信号光脉冲各点非线性相移差均衡,此时所需的控制光脉冲和信号光脉冲波形类似。 相似文献
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We present a new view of nonlinear distortion in a klystron based on an analytically solvable nonlinear Eulerian model. The nonlinear contributions to the analytic solutions for the beam modulations are "nonlinear space charge waves" in the sense that they are produced by the nonlinear mixing of the linear space charge waves. For a single-frequency input, amplitude and phase distortion are shown to be results of "self-intermodulation" at the drive frequency, or mixing of harmonic distortions with the fundamental. The self-intermodulation contributions add out of phase with the linear space charge waves to produce gain compression and phase distortion. By comparing the results to a conventional large-signal Lagrangian model we find this physical picture is accurate for drive levels up to 1.2 dB of gain compression. For a two-frequency input we predict the third-order intermodulation distortion generation and suppression with the nonlinear space charge wave theory. 相似文献
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S. K. Datta S. U. M. Reddy P. K. Jain B. N. Basu 《Journal of Infrared, Millimeter and Terahertz Waves》1999,20(3):483-490
A third-order nonlinear Eulerian hydrodynamic formulation was developed for the analysis of harmonic generation in helix traveling-wave tubes. The analysis was simple and computationally fast compared to Lagrangian analysis, and contrary to the existing belief, the theory could as well demonstrate the saturation behavior of the device. The performance of the theory was also found to be in close agreement with that of the Lagrangian analysis. The theory is expected to be useful as a first-hand design and simulation tool for microwave and millimetric wave traveling-wave tubes. 相似文献
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Haiyan Sun Chongqing Jiao Jirun Luo 《Journal of Infrared, Millimeter and Terahertz Waves》2008,29(7):657-662
Based on the nonlinear self-consistent theory of gyrotron traveling wave amplifier (gyro-TWA), the influence of the reflections of the output port with the taper on the beam-wave interaction in the gyro-TWA is studied. The simulation results show that the reflections have great effects on the TE01 mode gyro-TWA operating at the fundamental. The influence of the taper angle and the interaction length on the beam-wave interaction and the power profile is discussed and the corresponding physical mechanism is analyzed. The saturated output power keeps same approximately with the increase of the taper angle in the presence of reflection while the saturated gain decreases obviously. 相似文献
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An analysis of the nonlinear beam-wave interaction of the gyro-peniotron at high harmonic is presented in this paper. It bases on a ballistic large-signal theory of the gyropeniotron assuming a given RF field distribution in the resonator. The proposed method is applicable to arbitrary harmonic numbers and to arbitrary TE modes. Analytical results of its operational characteristics are given using computer simulations. E. g. an efficiency of 45% for the third harmonic has been calculated. The results show that the gyro-peniotron could be potentially a high efficiency, high power millimeter-wave device at a low magnetic field. 相似文献
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Accurate parametric modeling of folded waveguide circuits for millimeter-wave traveling wave tubes 总被引:6,自引:0,他引:6
Booske J.H. Converse M.C. Kory C.L. Chevalier C.T. Gallagher D.A. Kreischer K.E. Heinen V.O. Bhattacharjee S. 《Electron Devices, IEEE Transactions on》2005,52(5):685-694
In this paper, results of different models are compared for calculating effective, cold-circuit (beam-free) phase velocities and interaction impedances of folded waveguide (FW) slow wave circuits for use in millimeter-wave traveling wave tubes (TWT). These parameters are needed for one-dimensional (1-D) parametric model simulations of FW traveling wave tubes (FWTWTs). The models investigated include approximate analytic expressions, equivalent circuit, three-dimensional (3-D) finite difference, and 3-D finite element. The phase velocity predictions are compared with experimental measurements of a representative FW circuit. The various model results are incorporated into the CHRISTINE1D code to obtain predictions of small signal gain in a 40-55 GHz FWTWT. Comparing simulated and measured frequency-dependent gain provides a sensitive, confirming assessment of the accuracy of the simulation tools. It is determined that the use of parametric 1-D TWT models for accurate, full band predictions of small signal gain in FWTWTs requires knowledge of phase velocity and impedance functions that are accurate to <0.5% and <10%, respectively. Saturated gain predictions, being approximately half as sensitive to these parameters, appear to require correct specification of phase velocity and interaction impedance to within /spl sim/1% and 20%, respectively. Although all models generate sufficiently accurate predictions of the interaction impedance, not all generate sufficiently accurate predictions of the effective axial phase velocity. 相似文献
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Ohkawa M. Takahashi T. Huan-Bang Li Iigusa K. Wakana H. 《Broadcasting, IEEE Transactions on》2000,46(2):144-151
An advanced satellite broadcasting system using 21 GHz has been studied by using the high-power (200 W) and wideband (120 MHz) transponders on the Communication and Broadcasting Engineering Test Satellite (COMETS), which was launched 21 February 1998. A highly effective trellis-coded eight-phase-shift-keying (TC8PSK) modem was developed for the COMETS satellite broadcasting experiments, and this paper describes the degradation in the bit error performance of the TC8PSK modem due to the nonlinear amplification (AM/AM distortion and AM/PM conversion effects), group-delay distortion, and amplitude-frequency characteristics of the satellite transponder. The results of the COMETS experiments and computer simulations indicate that the performance degradation is due primarily to the nonlinear distortion and the amplitude-frequency characteristics of the traveling wave tube amplifiers in the transponder 相似文献
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Based upon Tien's disc model, a plastic three-dimensional (3D) super-particle model is proposed to improve the nonlinear analysis of helix travelling-wave tubes. The 3D space-charge forces are calculated, and 3D large-signal working equations are obtained. Numerical results employing a periodic magnetic focusing field are presented. The effects of the space-charge forces with respect to the different directions are investigated and a comparison of travelling wave amplifier (TWA) solutions obtained with the 3D model and the general two dimensional (2D) large-signal programs is given. The 3D electron motions are also analysed. Some useful conclusions, on both theory and experimental researches on TWAs, are obtained: (1) the 3D numerical results are obviously different from the 2D ones, in which the saturation gain decreases while the interaction length increases; (2) because the angular electron bunching results from axial spacial bunching in the helical 3D electron motions, there exists an angular space-charge force; despite the RF potentials and magnetic focusing fields being symmetrical around the axis; (3) the angular space-charge forces can be safely ignored whereas the radial and the axial space-charge forces must be included in the 3D calculation. 相似文献
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Laloue A. Nallatamby J.-C. Prigent M. Camiade M. Obregon J. 《Microwave Theory and Techniques》2003,51(8):1966-1976
The demand for autonomous cruise control and collision warning/avoidance systems has increased in recent years. Many systems based on frequency-modulated continuous-wave (FMCW) radar have emerged and are still in development. Due to the high complexity of such systems, the accurate evaluation of the noise spectra in the transmitter chain driven by complex modulated signals is today a severe drawback due to the limitation of simulation tools. In this paper, a method is proposed to compute easily with any commercially available nonlinear simulator, the amplitude and phase modulated signal distortion introduced by the nonlinearities of the transmitter on an FMCW signal. First, the amplitude modulation (AM) and phase modulation (PM) noise spectra of the driving FMCW signal is derived from the knowledge of the continuous wave (CW) AM and PM noise spectra of the voltage-controlled oscillator (VCO), and the modulating saw-tooth signal applied. Using the narrow band envelope concept and a first-order expansion of the nonlinear transfer function of the transmitter, the transfer of the AM and PM noise spectra of the driving FMCW signal through the nonlinear transmitter chain and the resulting output distortion are then computed. This novel approach allows to compute with reduced computation time and very good accuracy the AM/AM, AM/PM, PM/PM, and PM/AM conversion terms in any nonlinear system driven by CW or FMCW signals. This new method has been applied to the characterization of a whole car radar transmitter operating at 77 GHz driven by an FMCW signal issuing from a VCO. A successful comparison between measured and simulated PM-to-AM conversion coefficients of this transmitter is shown, validating the proposed method. 相似文献