排序方式: 共有16条查询结果,搜索用时 31 毫秒
1.
利用分形结构的自相似性将分形理论应用于频率选择表面(FSS)领域即可使在单屏FSS上具有多频段带通滤波的特性,结合Floquet周期边界条件,采用矩量法研究了二阶Y环分形FSS在不同入射角度下迭代比例因子F及单元排布方式对频率响应特性的影响规律,给出谐振频率的经验估算值.计算及实验结果表明,FSS的谐振频率主要由迭代比例因子及起始单元尺寸决定,而透过率及-3 dB带宽则对排布方式的改变较敏感.实验结果与理论分析一致. 相似文献
2.
Closely packed dense frequency selective surface 总被引:1,自引:0,他引:1
In order to realize wideband filtering properties of frequency selective surface (FSS), FSS of closely packed elements is presented. The Y loop elements are chosen as the graphics elements. Based on the spectral domain method, the frequency response is analyzed for different incident angles and polarizations. The result of the numerical analysis shows that the dense FSS has wide passband with better independence of angle and polarization. 相似文献
3.
Frequency selective surface with a flat topped passband 总被引:1,自引:0,他引:1
Two frequency selective surface (FSS) configurations with flat topped passband are presented in this paper. One configuration is single layer FSS with,λ/4 thickness dielectric loaded on both sides,and the other is double layers FSS.Based on the modal matching method,the frequency response properties including angle effect and polarization effect of both FSS configurations are analyzed,and the plots of the frequency versus transmission coefficient are obtained for different incident angles and polarizations.It is shown that the structure with the single layer FSS embedded centrally in the ,k/2 thickness dielectric has a wider flat top bandwidth of 6.8 GHz than that of the double layers FSS of 3 GHz.In addition,the fabrication of single layer is relatively easier than the double layers FSS. 相似文献
4.
等效电路法是分析主动FSS的主要方法,获得FSS集总参数是等效电路法分析问题的关键.本文在传统等效电路法基础上,根据传输线理论构造传递函数.依据等效阻抗与传输峰值之间的关系,建立由集总参数构成的矩阵方程,利用最小二乘法拟合得到等效集总参数,并借助传递函数快速得到FSS频响特性曲线.与全波分析法对比,传递函数法的计算结果与数值计算结果吻合,从而验证该方法的准确性和可靠性.该方法不仅能够获取FSS结构集总参数,还能够计算FSS结构的频响特性曲线,为基于等效电路法分析主动FSS提供理论参考. 相似文献
5.
为了分析电介质桁架结构对频率选择表面(FSS)传输特性的影响,以Y环单元的FSS和聚酰亚胺材质制备的桁架结构为例,采用时域有限差分方法进行计算和分析.建立物理模型并定义了孔径阻挡比P,通过分析证明了改变桁架的周期T以及肋骨的宽度D会对FSS的传输性能产生规律性影响,成为衡量电介质桁架结构的主要参数,且孔径阻挡比P的提高将增加传输损耗.当T值由无限大变为80 mm时,通带透过率平均下降超过0.9 dB;当D值由0变为20 mm时,通带透过率平均下降超过1 dB.当P值小于12.11%时通带不产生偏移现象;当P值小于4.12%时,桁架对FSS的影响可忽略不计.采用镀膜和光刻工艺制备FSS试件、数控机械加工方式制备电介质桁架,并在微波暗室中进行测量,验证实验与计算结果相符合,为拟采用电介质桁架结构的FSS隐身雷达罩工程应用提供了理论与实验的参考依据. 相似文献
6.
In order to realize the tunable performance of a frequency selective surface (FSS), a new unit cell is designed in this paper by properly adding two metal shorts to the ring slot. Based on the spectral-domain method, the frequency responses of the FSS structure with two shorts per slot ring are analysed for both the horizontal and the vertical polarizations at the normal incidence. It is demonstrated that the presence of the metal shorts does not affect the resonant frequency of the horizontally polarized wave but doubles the resonant frequency of the vertically polarized wave. Therefore based on the analysis of the novel transmission properties, a new approach to adjusting the resonant frequency by rotating the FSS screen 90? is presented in this paper. 相似文献
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8.
Frequency selective surface with better polarization-independency for arbitrary incident angle 总被引:1,自引:0,他引:1
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This paper investigates the frequency-selective property of a planar
layer consisting of period arrays both theoretically and
experimentally for different polarizations at arbitrary incident
angle. The novel element is designed by loading the rectangular
microstrip element with L-shaped conducting patch at its two ends.
Based on the spectral-domain method, the frequency response
including angle effect and polarization effect of the frequency
selective surface (FSS) structure are analysed and the plots of the
frequency versus transmission coefficient are obtained. As a result
of the numerical analysis, it is shown that if the source
polarization is changed, polarization-independence of previous FSS
design can be achieved only for normal incidence, which limits most
FSS applications. But in our proposed structure, the better
polarization-independency for arbitrary incident angle can be
achieved. It is observed that the simulated result comes very close
to the experimental result. 相似文献
9.
提出了球面旋涂微米级厚度光刻胶膜层薄化率公式及径向位置演变公式,并得到了膜厚分布的演变公式。与平面涂胶相比,球面涂胶离心力及重力分量是在不断的变化。根据平面旋涂运动方程及球面面形特征,给出了球面旋涂运动方程;结合流体层流的表面条件及不可压缩流体的质量连续方程,推导出了膜厚h及径向位置r对时间t的演变公式,并得到了在径向位置r处初始厚度为h0的膜厚演变的数学模型。通过对模型参数的分析可知,球面旋涂光刻胶应采用主从轴偏心旋涂,旋涂时工件的开口应朝向侧面(旋转轴水平)。 相似文献
10.
利用容性表面与感性表面之间的耦合机理能够制备微型化频率选择表面(MEFSS),周期单元尺寸将不受工作波长限制.为了提高MEFSS角度与极化的稳定性,展宽MEFSS的-3 dB带宽,文章结合传统频率选择表面"Y"形单元,利用"Y"图形构造容性表面的贴片单元与感性表面的网栅单元且以正三角形栅格拓展周期单元,采用矢量模匹配法对MEFSS栅格排布及其他结构参数变化进行精确计算.通过镀膜与光刻技术在0.15 mm厚聚酰亚胺膜两侧制备容性表面、感性表面并利用自由空间法测试.计算与实验结果均表明,采用正三角形栅格排布的MEFSS,-3 dB带宽达到7.6 GHz,不同极化下60°扫描时中心频点稳定在f0,为MEFSS应用于曲面天线罩时提供理论与实验参考依据.
关键词:
天线罩
微型化频率选择表面
容性表面
感性表面 相似文献