检索结果-南通市图书馆

Broadband high-efficiency plasmonic metalens with negative dispersion characteristic

Photonics Research 2024年第4期12卷 813-820页

作者： YONG-QIANG LIU YONG ZHU hongcheng yin JINHAI SUN YAN WANG YONGXING CHE National Key Laboratory of Scattering and Radiation Beijing 100854China

Controlling the dispersion characteristic of metasurfaces(or metalenses) along a broad bandwidth is of great importance to develop high-performance broadband metadevices. Different from traditional lenses that rely on the material refractive index along the light trajectory, metasurfaces or metalenses provide a new regime of dispersion control via a sub-wavelength metastructure, which is known as negative chromatic ***, broadband metalenses design with high-performance focusing especially with a reduced device dimension is a significant challenge in society. Here, we design, fabricate, and demonstrate a broadband highperformance diffractive-type plasmonic metalens based on a circular split-ring resonator metasurface with a relative working bandwidth of 28.6%. The metalens thickness is only 0.09λ0(λ0is at the central wavelength),which is much thinner than previous broadband all-dielectric metalenses. The full-wave simulation results show that both high transmissive efficiency above 80%(the maximum is even above 90%) and high average focusing efficiency above 45%(the maximum is 56%) are achieved within the entire working bandwidth of 9–12 ***, an average high numerical aperture of 0.7(NA = 0.7) of high-efficiency microwave metalens is obtained in the simulations. The broadband high-performance metalens is also fabricated and experimental measurements verify its much higher average focusing efficiency of 55%(the maximum is above 65% within the broad bandwidth) and a moderate high NA of 0.6. The proposed plasmonic metalens can facilitate the development of wavelength-dependent broadband diffractive devices and is also meaningful to further studies on arbitrary dispersion control in diffractive optics based on plasmonic metasurfaces.

关键词： resonator dispersion high

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于宽带极化纯度估计的极化测量定标修正

引用

系统工程与电子技术 2024年第2期46卷 428-436页

作者：白杨殷红成黄培康刘芳中国传媒大学信息与通信工程学院北京100024 北京环境特性研究所电磁散射重点实验室北京100854

对扩展目标极化散射特性进行测量时,通常期望精确获得宽带高分辨条件下目标各散射中心的极化特征信息,但由于各极化分量散射的信号对测试系统的正交极化通道存在能量泄漏,会严重影响较弱的极化散射分量的测量准确性。基于极化散射测量... 详细信息

对扩展目标极化散射特性进行测量时,通常期望精确获得宽带高分辨条件下目标各散射中心的极化特征信息,但由于各极化分量散射的信号对测试系统的正交极化通道存在能量泄漏,会严重影响较弱的极化散射分量的测量准确性。基于极化散射测量定标原理与宽带高分辨极化测量表征模型,分析了干扰量的产生原因以及对散射中心测试结果的影响机理,提出了一种基于宽带正交极化纯度估计进而修正复杂目标极化测量结果的方法,并通过对金属球、金属二面角组合和类弹头金属模型3类典型目标的实测,验证了其有效性。

关键词：极化散射矩阵极化定标高分辨雷达目标测量

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comparison between two concepts of angular glint:general considerations

引用

Journal of Systems Engineering and Electronics 2008年第4期19卷 635-642页

作者： Wang Chao yin hongcheng Huang Peikang Information Engineering School Communication Univ. of China Beijing 100024 P. R. China National Electromagnetic Scattering Lab. Beijing 100854 P. R. China

Angular glint can be interpreted as a distortion of the radar echo signal phase front, or alternatively, a tilt of the direction of energy flow from the radial direction. As the complementarities and support of argumentation in our previous work, a general discussion about two concepts of angular glint is made based on electromagnetic theory to demonstrate that these two concepts are equivalent when geometrical optics approximation is used and＇ the receiving antenna is linearly polarized.

关键词： angular glint radar target electromagnetic scattering polarization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Equivalent Currents on an Anisotropic Material Backed by a Metal Surface and Their Relation

引用

Journal of Systems Engineering and Electronics 2000年第4期11卷 1-10页

作者： Huang Peikang yin hongcheng National Electromagnetic Scattering Laboratory Beijing 100854P.R.China

Based on a first-order state-vector differential equation representation of Maxwell's equations, an analytical formulation is derived for the equivalent currents on an anisotropic material backed by a metal surface, and the relation between two currents is also considered. These expressions are degenerated into the common forms for some simple cases. This effort will provide the theoretical preparation for the approximate calculation of electromagnetic scattering from a conducting object coated by an anisotropic material.

关键词： Radar absorbing material Anisotropic Equivalent currents Electromagnetic scattering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Unification and Comparison between Two Concepts of Radar Target Angular Glint

引用

Journal of Systems Engineering and Electronics 1992年第1期3卷 35-44页

作者： hongcheng, yin Peikang, Huang Beijing Institute of Environmental Features Beijing China

This paper provides a general proof of unification between two concepts of radar target an gular glint. The analysis of a two-point target model, consisting of a electrically and a magnetically ideal dipole, shows the relation, difference and equivalent condition between them more clearly. Angular glint has been synthesized from the measured data of radar echo phase, and compared with the theoretical result.

关键词： Image processing Radar measurement

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Renormalization: single-photon processes of two-level system in free space

引用

Journal of Systems Engineering and Electronics 2020年第5期31卷 908-915页

作者： WANG Chong ZHU Yong LI Liangsheng yin hongcheng Beijing Institute of Environment Features Beijing 100854China Science and Technology on Electromagnetic Scattering Laboratory Beijing Institute of Environmental FeaturesBeijing 100854China

The investigation on quantum radar requires accurate computation of the state vectors of the single-photon processes of the two-level system in free space. However, the traditional Weisskopf-Wigner(W-W) theory fails to deal with those processes other than spontaneous emission. To solve this problem, we provide a new method based on the renormalization theory. We evaluate the renormalized time-ordered Green functions associated with the single-photon processes, and relate them to the corresponding state vectors. It is found that the ultraviolet divergences generated by the Lamb shift and higher-order interactions can be systematically subtracted in the state vectors. The discussions on spontaneous emission and single-photon absorption are then presented to illustrate the proposed method. For spontaneous emission, we obtain the same results of the W-W theory. For single-photon absorption where W-W theory fails, we find that the two-level electric dipole first gets excited rapidly and then decays exponentially, and that the efficiency of the single-photon absorption declines as the bandwidth of the incident photon becomes narrow. The proposed method can improve the investigation on quantum radar.

关键词： single-photon process two-level system(2LS) renormalization time-ordered Green function(RTGF) quantum radar

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Polarization characteristics and controllability mechanism of passive scattering elements

引用

系统工程与电子技术：英文版 2023年第2期34卷 342-349页

作者： GUO Jie yin hongcheng MAN Liang LI Xin Science and Technology on Electromagnetic Scattering Laboratory Beijing 100854China Beijing Institute of Environmental Features Beijing 100854China

Polarization feature is one of the important features of radar targets,which has been used in many *** this paper,the grid models of some typical foreign moving targets are constructed on the simulation platform,such as glider,cruiser,fixed wing aircraft,and *** electromagnetic scattering characteristics of the moving platforms under the incidence of circular polarization waves are *** typical polarization characteristics which the orthogonal and in-phase components have in the echoes are analyzed and *** on the polarization scattering matrix(PSM)theory,from the point of view of the physical reproduction,the technical status quo that the existing technical approaches are difficult to realize the passive simulation of polarization characteristic of the target is *** solve this problem,combined with the vector synthesis law,the realization mechanism of controllable polarization characteristic of target echoes is proposed,the analytical expressions of polarization control matrix and polarization ratio are deduced,and the controllability of polarization ratio feature in the case of circular polarization is verified by simulation calculation.

关键词： polarization characteristic physical reproduction passive scattering element controllability mechanism radar feature simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Airborne sparse flight array SAR 3D imaging based on compressed sensing in frequency domain

引用

Journal of Systems Engineering and Electronics 2023年第1期34卷 56-67页

作者： TIAN He DONG Chunzhu yin hongcheng YUAN Li Science and Technology on Electromagnetic Scattering Laboratory Bejing Insititute of Environment FeaturesBeijing 100854China

In airborne array synthetic aperture radar(SAR), the three-dimensional(3D) imaging performance and cross-track resolution depends on the length of the equivalent array. In this paper, Barker sequence criterion is used for sparse flight sampling of airborne array SAR, in order to obtain high cross-track resolution in as few times of flights as possible. Under each flight, the imaging algorithm of back projection(BP) and the data extraction method based on modified uniformly redundant arrays(MURAs) are utilized to obtain complex 3D image pairs. To solve the side-lobe noise in images, the interferometry between each image pair is implemented, and compressed sensing(CS) reconstruction is adopted in the frequency domain. Furthermore, to restore the geometrical relationship between each flight, the phase information corresponding to negative MURA is compensated on each single-pass image reconstructed by CS. Finally,by coherent accumulation of each complex image, the high resolution in cross-track direction is obtained. Simulations and experiments in X-band verify the availability.

关键词： three-dimensional(3D)imaging synthetic aperture radar(SAR) sparse flight interferometry compressed sensing(CS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

New hybridization of PO, SBR, and MoM for scattering by large complex conducting objects

引用

Journal of Systems Engineering and Electronics 2007年第4期18卷 726-730页

作者： Dong Chunzhu Geng Fangzhi yin hongcheng Wang Chao National Electromagnetic Scattering Lab. Beijing 100854 P. R. China Dept. of Electronic Warfare AFRA Wuhan 430019 P. R. China

As a marked extension of the traditional MoM-PO （method of moment-physical optics） hybrid method, a new hybridization of PO, SBR, and MoM （MoM-SBR/PO） is presented to calculate the multireflection contribution in the PO region efficiently by introducing the method of SBR based on RDN notion, which avoids the time-consuming iterative procedure and the choice of proper Green＇s function. As compared with the traditional MoM-PO hybrid method, the calculation efficiency of the proposed method is greatly improved, and its validity is verified by numerical results.

关键词： the method of moment (MoM) physical optics (PO) hybrid method shooting and bouncing ray(SBR) EM scattering radar cross section (RCS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Synthesis of Load Impedances That Reduce TE-Scattering from Conducting Cylinder with Arbitrary Cross Section

引用

Journal of Systems Engineering and Electronics 1997年第4期8卷 40-49页

作者： yin, hongcheng Huang, Chen Xiao, Zhihe Air Force Radar Research Inst Beijing China

The reduction of TE-scattering by a conducting cylinder with multiple surface impedance loads is investigated. Synthesis procedures are developed to find the optimal loading which result in zero scattering in the desired directions or at several frequencies. Numerical results of these procedures are presented. The theoretical predictions are confirmed with an experiment. The proposed synthesis procedure is completely general and can be applied to arbitrarily shaped conducting bodies.

关键词： Electromagnetic scattering Impedance loading Impedance synthesis Radar cross section.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：