共查询到19条相似文献,搜索用时 109 毫秒
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微波脉冲窄缝耦合的数值模拟方法 总被引:3,自引:0,他引:3
本文应用一种近似方法,结合时域有限差分法,模拟了微波脉冲与腔体上有限厚度孔缝的线性耦合过程,给出了耦合场对入射波载频、入射场偏振方向、腔体壁电导率以及孔缝尺寸的依赖关系,得出了微波脉冲与孔缝耦合的共振效应和增强效应等规律。 相似文献
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应用时域有限差分法(FDTD)模拟计算了微波脉冲与带缝非金属腔体的线性耦合过程.在正弦波凋制的高斯脉冲源激励下,分析了耦合场在腔体内的分布情况,总结了相对介电常数、腔壁厚度、孔缝尺寸等因数对耦合特性影响的基本规律.结果表明:在入射电场方向腔体中心轴线上的耦合场基本保持不变,垂直于入射电场截面上耦合场关于截画中心点呈对称分布;耦合进腔体的能量随厚度的增加和介电常数的增大而减小,但介电常数的影响更加明显,且随孔缝面积的增大而增大,面积一定时,随纵横比的增大而增大;孔缝中心处的电场耦合系数峰值随介电常数的增大呈近似线性下降,而腔体中心处呈振荡减小,在相对介电常数为6左右电场时域峰值达到最大;腔体内耦合磁场的变化规律与电场的类似. 相似文献
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矩形金属机壳孔缝电磁耦合特性研究 总被引:1,自引:0,他引:1
针对矩形金属机壳上孔缝在高功率电磁环境下的电磁耦合问题,提出了一种使用模式匹配法和基于矩量法求解的混合位积分方程来分析孔缝电磁耦合特性的全波混合算法.该算法考虑了高次模、孔缝形状、孔缝厚度以及入射波极化方向等因素对电磁耦合特性的影响.通过将数值仿真结果与经典孔缝电磁耦合模型的测试结果进行对比,验证了该算法具有较高的准确性,与经典的时域有限差分法相比,该算法具有很高的计算效率.研究结果表明:有孔金属机壳在外界强电磁辐射条件下具有明显的谐振效应,在谐振频率点,耦合进入机壳的电场将大大增强,且孔缝附近以及机壳中心的耦合电场峰值要高于其他位置的耦合电场峰值;随着机壳表面上孔缝厚度的增加,耦合进入其内部的电场也在减弱;当机壳上的孔缝为矩形且入射波的电场极化方向平行于矩形缝隙的短边时,对应于该极化方向的孔缝电场耦合强度是所有极化方向中最强的. 相似文献
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介绍了核电磁脉冲通过孔缝耦合到系统内部的最大能量计算方法,给出了倒指数型电磁脉冲最大耦合能量的解析表达式。该模型在定孔总截面正比于波频率4次方时,计算出通过孔耦合到腔体内部的最大能量,实现电磁耦合能量的计算。倒指数脉冲模型的理论计算结果,可以对电子设备电磁脉冲的保护具有重要意义。 相似文献
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NUMERICAL STUDIES ON RESONANT AND ENHANCEMENT EFFECTS FOR COUPLING OF MICROWAVE PULSES INTO NARROW SLOTS 总被引:1,自引:0,他引:1
Wang Jianguo Yu Hanqing Liu Guozhi Chen Yusheng Fan Ruyu 《电子科学学刊(英文版)》1998,15(2):174-181
In this paper, modifications to the finite-difference time-domain(FD-TD) method for modeling microwave pulse coupling into a slot, which is much narrower than one conventional FD-TD cell, are discussed. The coupling process of microwave pulse into a slot is studied by using the modified FD-TD method, and the dependence of microwave coupling on slot sizes, the carrier frequencies and the polarization directions of the incident waves is analysed. Resonant and enhancement effects which occur in this process are observed. The condition at which the resonant effect takes place is also presented. 相似文献
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This paper analyzes the influence of the microwave pulse repetition frequency on the thermal burnout effect of a PIN diode limiting-amplifying system. Based on the study of the single-shot microwave pulse thermal burnout effect and by introducing a new assumption that the heat dissipation of the electric field energy and the nonequilibrium carrier energy during the microwave pulse intervals can be neglected, the theoretical thermal burnout model in our previous study is extended to be suitable for repetitive microwave pulses. The theoretical relationship among the pulse number, the pulse repetition frequency, the pulse width and the thermal burnout power threshold is obtained by theoretical derivation. Because the assumptions are introduced, the theoretical relationship requires that both the whole length of a repetitive microwave pulse and the pulse width in a cycle of a repetitive microwave pulse should be between 10 ns and 10 μs. The results obtained by the theoretical relationship are in good agreement with the simulation results obtained by our self-designed device-circuit joint simulator, which verifies the correctness of the theoretical analyses, modeling and derivation. By fitting at least two sets of simulation or experimental data, the theoretical relationship can be used to predict the thermal burnout power thresholds of PIN diode limiting-amplifying systems under microwave pulse injections with different pulse parameters. It can greatly reduce the simulation or experimental costs and could be helpful for the design of a radio frequency receiver. 相似文献
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The dynamic response of a traveling-wave (TW) electrooptic phase modulator is treated using a Fourier transform technique. An integral expression for the induced phase shift which takes into account the optical-microwave velocity mismatch and the microwave attenuation is derived. In the case of a Gaussian modulating pulse and negligible microwave attenuation, the temporal dependence of the modulated pulse amplitude can be expressed in terms of error functions. Calculated pulse shapes showing the transition from a Gaussian to a flat top output pulse with increasing phase mismatch in the absence of microwave attenuation are presented. The effect of microwave attenuation on pulse shape, amplitude, and width is also explored. The method used to obtain these results is generally applicable to the time-domain analysis of TW modulators 相似文献
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《Microwave Theory and Techniques》1983,31(8):669-671
In this paper an analysis of the scattering matrix coefficients (reflectance and transmittances) of the microwave resonators is presented. Two general cases of resonator couplings are considered. One of them is a multiport with one port terminated by the resonator, the other is a resonator coupled, in various ways, to a number of transmission lines. The effect of external circuits on the Q and resonant frequency of the resonator has also been examined. Fundamental parameters for the commonly used microwave resonator couplings are shown in Table L 相似文献
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In this paper, the influence of microwave pulse width on the thermal burnout effect of a low noise amplifier (LNA) constructed by a GaAs pseudomorphic high electron mobility transistor (PHEMT) is theoretically analyzed and further verified with simulation and experimental results. By analyzing the electrical procedure and the thermal procedure, a theoretical model of the thermal burnout effect of the studied LNA is established according to the properties of microwave pulses and the structure of the LNA and GaAs PHEMT. Based on the theoretical model, the analytical relationship between the microwave pulse width and the thermal burnout power threshold is further obtained. According to the limitations caused by the approximations in the process of modeling, the available microwave pulse width range for the proposed analytical relationship is more than a nanosecond level and less than a microsecond level. The coefficients of the proposed analytical relationship can be determined by fitting at least two sets of simulation or experimental results, which can greatly reduce the simulation or experimental costs. Finally, the analytical relationship is verified by simulation and experimental results. The results show that the proposed analytical relationship is suitable to estimate the thermal burnout power threshold for a given microwave pulse width within the limit of microwave pulse width range. 相似文献
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In this paper, we present a semiclassical wave equation analysis using a coupled-mode expansion formalism to study the effect of a microwave field on a train of short optical pulses co-propagating in a traveling-wave modulator structure. This device can continuously shift the central frequency of light pulses. We demonstrate the effect of the applied field on the light spectrum, the dependence on the relation between microwave wavelength and pulse length, and the effect of changing the interaction length or the power of the applied microwave field. The results of the calculation of these effects are presented. 相似文献
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Maxim L. Kulygin Gregory G. Denisov Vladimir V. Kocharovsky 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(1):31-40
Problems of high-power microwaves penetrating into and reflecting from a semiconductor (silicon) plate with non-stationary
processes are investigated. The plate is the basis of switches activated by laser-driven photoconductivity which changes its
properties when heated by the switched microwave power. Analytical criteria for the stationary solutions of the activated
(quasi-metallic) and deactivated (dielectric) states of the switch under the conditions of high-power microwave heating and
external cooling are found. Results of numerical simulations are also given for the problems of the switch activation by microwave
heating initiated by pulsed laser radiation, which increases the carrier density rapidly. Numerical simulations are carried
out using the finite-difference time-domain method with the unsplit perfectly matched layer absorbing boundary conditions.
We demonstrate various types of solutions depending on the basic parameters of the problems - microwave field intensity, laser
pulse energy and semiconductor doping. 相似文献
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This paper analyzes the influence of the microwave pulse width on the thermal burnout effect of a PIN diode limiting-amplifying system. Based on theoretical analyses and simulation, the relationship of the burnout effect on a PIN diode limiter and a PIN diode limiting-amplifying system is obtained first. By adopting an absorption efficiency factor, the theoretical model of the relationship between the microwave pulse width and the burnout power threshold for the PIN diode limiting-amplifying system is obtained. The proposed theoretical formulas can be determined by using at least two sets of simulation or measurement results to fit the constant coefficients, which can greatly reduce the simulation or experimental costs. The results obtained by the theoretical formulas are in good agreement with the numerical simulation results obtained by our self-designed device–circuit joint simulator, which verifies the correction of the theoretical analyses and modeling. The available microwave pulse width range for the proposed theoretical formulas is from 10 ns to 10 μs. In consideration of the potential threat of microwave pulses, the system-level study results obtained in this paper will be helpful for the design of the radio frequency receivers. 相似文献