共查询到20条相似文献,搜索用时 109 毫秒
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为详细研究UWB(超宽带)、HEMP(核电磁脉冲)作用下长线缆的场线耦合效应问题,并将二者进行比较,依据场线耦合效应计算的Agrawal、Vance模型,推导了能有效用于场线耦合效应编程计算的实用算式.在此基础上编写了Matlab计算程序,对UWB和HEMP作用下长线缆的场线耦合效应进行了计算、分析和比较,得出了两种强场作用下的效应规律.计算显示,UWB和HEMP都能在线缆上激励较高的电流脉冲,也能在线缆端部激励较强的干扰电压脉冲;在相近条件下,UWB激励的响应弱于HEMP;二者相比,其场线耦合效应既有相似之处,又有不同的特点. 相似文献
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传输线是各种电子电气设备中的常见结构,是信号传递、能量传输的重要通道,同时也是电子电气系统中极易受到外界电磁脉冲干扰的对象之一。电磁脉冲与传输线之间的耦合问题一直是国内外研究者关注的一个热点。文章介绍了低频情况下研究场线耦合问题的经典传输线模型,并对基于传输线模型的BLT方程、SPICE等效电路模型发展历程、研究现状进行了较为详细的分析和总结,同时梳理了传输线方程FDTD解法的发展脉络。之后,简要介绍了高频情况下常用的场线耦合模型。最后,就当前场线耦合问题中被广泛关注的部分热点问题进行了分析和讨论,并指出了一些亟待完善的地方。 相似文献
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随着新能源技术的不断发展,多频器件和高压线束的大量应用使新能源车辆电磁兼容问题日趋复杂,研究特种车辆新能源充电线缆的复杂电磁环境效应与防护问题具有重要工程价值。文中选择一种新能源充电线缆,利用三维电磁场仿真软件(CST)建立电磁干扰源和充电线缆模型。基于场线耦合原理,仿真分析高空核电磁脉冲照射下的混合动力装甲车内部新能源充电线缆电磁响应。仿真结果表明,同一线束同种线缆横截面积越大,线缆端口耦合电流越大;在同一干扰脉冲照射下,不同线缆端口耦合电流达到峰值的时间以及开始衰减的时间不同;以及线缆布局影响线缆端口耦合电流的大小;线缆阻抗匹配时的耦合电流远远大于阻抗失配时的耦合电流;新能源充电线缆与传统车载SYV-50-3同轴线缆的高空核电磁脉冲响应变化规律吻合良好。 相似文献
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A general theory for graphical representation of antenna radiated fields is developed. The application of the method to the special case of a transverse electromagnetic-mode-excited biconical antenna is investigated in detail. Electric field lines in the r -ϑ plane of a spherical coordinate system are presented in a manner such that the same electric flux is always carried between two neighboring field lines. Thus, their mutual distance is a criterion for the strength of the local electric field. The differential equations which govern the displacement of a field point are derived and solved. The time-dependent evolution of a field-line pattern is examined in detail. The new theory for graphical field representation permits, in an elegant manner, the analysis of the transmission and receiving mechanism of arbitrary antenna configurations. Thus, it is suggested that an iterative graphical synthesis procedure could, in the future, be applied to the computer-aided design modeling of antenna shapes 相似文献
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为了系统研究影响耦合效率的因素,采用仿真和实验的方法建立了半导体激光器与单模光纤的耦合模型,并搭建自动耦合平台,进行了理论分析和实验验证,得到了模型的耦合效率与各个方向位移敏感度的关系以及实际耦合过程中耦合效率与各个方向容忍度的关系。结果表明,耦合效率对水平方向位移最为敏感,其后依次是角度旋转和纵向位移; 仿真与实验最大耦合效率分别为64.29%与51.46%,误差在合理范围之内,结果具有较高可信度。这一结果对实际光电器件封装耦合效率的提高是有帮助的。 相似文献
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谐振法测量介质介电常数时需要计算谐振器的无载Q值。当微波谐振器的工作模式受干扰模式影响时,会导致无载Q值的计算出现偏差。文章针对这种情况提出了一种存在干扰模式时计算微波谐振器无载Q值的迭代算法。该方法基于所提出的反向叠加和同相叠加两种等效电路模型,以传输系数模值平方之差在所有频点的平方之和作为目标函数,采用尺度变换最速下降法进行迭代。将圆柱形金属谐振腔的高Q值TE011模作为工作模式、简并的低Q值TM111模作为干扰模式,通过仿真和实测对该方法进行了验证。实测结果表明,当干扰模式较强时,3 dB法计算的工作模式Q值偏离真值14%,而所提出的迭代法的计算结果偏离真值不到1%。 相似文献
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S. J. Xu S. T. Peng F. K. Schwering 《Journal of Infrared, Millimeter and Terahertz Waves》1987,8(9):1001-1013
The coupling between two parallel dielectric waveguides with a finite coupling length is investigated. The ends of the waveguides are tapered in order to reduce the scattering losses. It is shown that the taper sections can be utilized to achieve an effective coupling which is insensitive to the coupling length, thus, providing a much greater tolerance for the design and manufacturing of coupling devices. 相似文献
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We discuss certain properties of the coupling coefficients for a specific model consisting of two coupled resonant cavities separated by a lossy coupling gap. The coupling coefficients are here defined in the framework of time-dependent coupled-cavity theory-not as end-fire power coupling between traveling waves of two adjacent waveguides. In particular, we explore the validity of a heuristic formula for the coupling coefficients proposed in an earlier publication. It turns out that, in this example, the heuristic formula is directly applicable only if the coupling gap is lossless and off-resonance, but it becomes inapplicable if the lossless gap approaches resonance. The heuristic formula remains useful, but requires a correction if the coupling gap is lossy. The phase angle of the complex coupling coefficient is found to be linearly dependent on the width of the coupling gap, assuming the value 0 (to within multiples of 2π) for an off-resonant gap and the value ofpi/2 for a resonant gap. It is not the purpose of this letter to explore properties of c3lasers or to specify their optimum operating conditions. Only the validity of the approximate coupling function is to be investigated. 相似文献
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The mode excitation theory is presented to analyze single-mode optical fiber directional couplers with transverse strong coupling, which either the weakly coupling theory or the ray theory fails to expound. By using the equivalence between the waveguides with square and circular cross sections, regarding the coupling zone of the coupler as a single waveguide, the excitation coefficients of the propagation modes in the coupling zone excited by the modes in the input waveguide have been evaluated. The theoretical coupling amount and insertion loss have been studied. Using a special monitoring technique to control the coupling length, several couplers with various coupling amounts have been made by the polishing method. The spectral characteristic of the coupling amount has been measured and compared with the theoretically inferred result. The two are found to agree with each other. The offset effect on the coupling amount has also been measured and it is different from that of the weak coupling device-the Stanford coupler. 相似文献
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为了解决分布式反馈激光器的光发射次模块耦合封装中存在最大耦合效率局限的问题, 采用楔形截顶光纤微透镜代替分立式透镜的直接耦合的方法, 得到斜面倾角0.6rad、耦合距离60μm、半宽度15μm的楔形截顶光纤端面模型。在此基础上与分立式和直接耦合进行对比, 讨论了纵向、横向和角度偏移误差。结果表明, 纵向耦合距离在-21.45μm~56.79μm, 角向耦合角度在-8.3°~8.5°, 耦合效率始终大于70%;结构整体容忍度较高, 耦合效率达84.40%。该研究可为下一代分布式反馈激光器的次发射模块耦合封装器件提供新的解决方案。 相似文献