共查询到19条相似文献,搜索用时 140 毫秒
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本文在圆柱坐标系下通过MAXWELL方程,将三维问题转换为一维问题,产生相应控制方程。利用时域特征线算法(characteristic—based time domain method)计算了探针馈电重叠圆柱共形微带天线的输入阻抗和辐射方向图。本文特点是数值计算误差小,与传统算法相比,缩短了计算时间。计算结果与FDTD算法结果吻合良好,证明了本文理论与数值模型的可行性和精确性。 相似文献
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研究了小曲率半径有限长度圆柱体上共形蝶形微带天线的阻抗特性和方向图.给出了不同曲率半径下的柱面共形蝶形微带天线反射损失和方向图的仿真结果.实际制作和测试了柱面共形微带天线的单元和二元阵列天线,仿真结果与实测结果比较吻合.研究表明:当圆柱半径较小时,不但方向图改变,而且谐振频率下降、阻抗带宽明显减小;当圆柱长度缩短时,方向图的起伏增大. 相似文献
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一种圆柱共形的全向微带天线 总被引:1,自引:0,他引:1
提出了一种全向的圆柱共形矩形微带天线。阐述了这种在薄圆柱形介质基片上的矩形微带天线的分析方法和设计方法,并给出了理论和实验结果,证实了这种天线在垂直于柱体轴的平面内辐射出全向性的方向图。 相似文献
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基于并矢格林函数分析环绕微带共形天线 总被引:2,自引:0,他引:2
本文导出了涂覆无耗介质层的无限长金属圆柱结构的并矢格林函数以及与这种结构共形的微带天线辐射场的一般表达式,并利用表面电流模型法研究了介电常数,介质层厚度和金属圆柱体半径对环绕微带共形天线方向图的影响。 相似文献
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以弹载共形相控阵雷达导引头天线为应用背景,在未考虑极化的情况下,首先推导了任意共形天线单元方向图从局部极坐标系到全局极坐标系转换的一种实用方法;然后采用凹槽加载的中心馈电方式设计了毫米波锥面共形微带天线单元,并建立锥面共形相控阵天线模型,推导了锥面共形天线阵列的导向矢量及其方向图函数;最后采用能量迭代法对15 阵元的锥面共形相控阵天线方向图进行了仿真优化,在副瓣电平约束和零点约束两种情况下,分别给出了相应最优加权矢量的求解方法,实现了对方向图波束指向、副瓣电平以及零点的控制。 相似文献
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UPML媒质中无条件稳定的二维ADI-FDTD方法 总被引:2,自引:0,他引:2
对单轴各向异性PML(UPML)媒质中二维TM波的交变方向隐式时域有限差分方向(ADI-FDTD),通过计算实例表明,ADI-FDTD方法在UMPL媒质中是无条件稳定的,其时间步长不受CFL稳定性条件的限制,并且当计算区域内具有精细差分网格时,其计算效率明显优于传统的时域有限差分方向(FDTD)。 相似文献
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采用非分裂式理想匹配层(UPML)的时域有限差分(FDTD)法对矩形微带天线及低通滤波器等微带电路进行了分析计算,给出了时域和频域的仿真结果。与其他的理想匹配层(PML)相比,UPML利用D和H,物理概念明确,将PML区域与FDTD计算域隔离开来,并且减少了PML吸收边界计算所占用的存储量。从仿真结果看,该方法有效且极大减少了迭代次数。 相似文献
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微带可重构天线的初步探讨 总被引:6,自引:0,他引:6
引入了一种崭新的天线概念-可重构天线。首先根据传统微带天线腔模理论定性地分析了微带可重构天线的工作机理,然后用时域有限差分(FDTD)法对微带天线的可重构特性进行了仿真分析。仿真和分析表明,矩形微带可重构天线当某一边长大于等于一个工作波长时,能够获得良好的可重构特性。 相似文献
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An efficient technique for the analysis of a general class of microstrip structures with a substrate and a superstrate is investigated in this paper using newly-derived closed-form spatial domain Green's functions employed in conjunction with the Method of Moments (MoM). The computed current distributions on the microstrip structure are used to determine the scattering parameters of microstrip discontinuities and the input impedances of microstrip patch antennas. It is shown that the use of the closed-form Green's functions in the context of the MoM provides a computational advantage in terms of the CPU time by almost two orders of magnitude over the conventional spectral domain approach employing the transformed version of the Green's functions 相似文献
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He Mang Xu Xiaowen 《Antennas and Propagation, IEEE Transactions on》2004,52(7):1749-1757
The input impedance and radiation pattern of the probe-fed multilayered cylindrical-rectangular microstrip antennas (PMCMSA) are analyzed by using a novel approach which combines the conformal finite-difference time-domain (FDTD) and Gedney's unsplit version of the perfectly matched layer absorbing boundary condition method and the Green's functions in cylindrically stratified media. The near fields of such antennas and the current distributions on the patches are obtained by the conformal FDTD method numerically and then the modified spectral-domain Green's functions in arbitrary cylindrically stratified media are used to determine the radiation pattern. The effect of the small radius of the probe on the performance of antennas is investigated through the thin-wire algorithm in cylindrical coordinates. A simple design scheme of the probe-fed cylindrically stacked antennas is also proposed for increasing the impedance bandwidth. 相似文献
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In this paper, a time domain method is introduced for analyzing microstrip antennas having thin slots. The present method is based on a resolution of Maxwel?s. equtions using the finite difffreence time domain method. A particular investigation has been made for taking thin slots into account, this avoids a prohibitive grid to represent the slots. Two kinds of antennas have been analyzed by this method: the slot antennas and the radiatins patch fed by a line through a slot. 相似文献
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Yong-Xin Guo Kwai-Man Luk Kwok-Wa Leung 《Microwave Theory and Techniques》1999,47(11):2164-2166
The mutual coupling between aperture coupled cylindrical dielectric-resonator antennas (DRAs) is analyzed using the finite-difference time domain method. The perfectly matched layer is used as absorbing boundary conditions. The voltage excitation source of microstrip structure is based on the Zhao's model, in which the source plane or the terminal plane can be moved very close to the discontinuity so that the computational domain can be reduced substantially. The numerical results are verified by measurements and reasonable agreement between theory and experiment is obtained. It is shown that this method is highly efficient for the analysis of DRAs 相似文献