天线时域平面近场测量系统的研究

时域近场测量作为一种新发展起来的天线测量技术,具有和通常的频域测量不同的独特优势,它能得到天线的时域特性和宽带特性.首先介绍了时域平面近场测量系统的构成,为了能对雷达进行测量,系统采用了使用矢量信号源模拟产生复杂雷达信号的方案,并对标准增益喇叭进行了验证测试,把测试结果和理论仿真、频域近场测试结果进行了比对,证实了时域...     

天线时域平面近场测试实验系统的研究

天线时域近场测试技术是一种新兴、高效的天线测试技术,能够快速精确地测量出天线的时域场和宽带特性。目前我们已成功组建了国内第一套天线时域平面近场测试实验系统,并对L、S、C、X四个波段的标准天线方向图进行了验证测试,把测试结果跟频域近、远场测试系统上测得的结果进行比较,证明时域近场测试理论的正确性和测试系统的实用性。本文对这套系统的组成结构和天线的测试结果进行说明分析。     

"时间窗"对天线时域平面近场测试结果的影响

天线时域近场测试技术是一种新兴的、测试宽带场和工作在窄脉冲激励下天线辐射场的高效的测试技术.因为它可以利用"时间窗"技术进行信号处理,使其相对频域测试具有独特的优势.本文在已建立的天线时域近场测试系统的基础上,从实验的角度,对"时间窗"参数在天线时域平面近场测试中的影响进行验证分析.举例了三个波段标准天线方向图的测试分析结果,并得出初步结论.     

天线时域近场测量技术与实验系统

天线时域近场测试技术是一种新兴、高效的天线测试技术,能够快速精确地测量出天线的时域场和宽带特性。介绍了成功组建的国内第一套天线时域平面近场测试系统简单情况,给出了L、S、C、X四个波段的标准天线方向图验证测试结果,把测试结果跟频域近、远场测试系统上测得的结果进行了比较,证明测试理论的正确性和测试系统的实用性。     

天线时域近场测量实验系统研究

总结了天线时域近场测量技术研究中进行系统实验验证在个阶段的进展情况,提出了组建天线时域近场测试验证系统的基本框架,总结了验证实验的基本过程和思路,提出了一种利用离散傅立叶反变换（IDF）技术完成天线的时域近场测量的方法,本文给出了各个实验阶段的测试结果,据此得出了对于天线的时域近场测量技术肯定的结论。     

天线时域平面近场测试的误差分析

天线时域近场测试技术对误差体系研究的缺失,导致测试结果的不确定度分析一直无法完成.为解决这一问题,以天线时域平面近场测试为例,对时域近场测试的误差进行研究,给出时域测试区别于频域测试技术的四个误差项:探头调制误差、信号源稳定度误差、时间采样间隔误差、时间采样长度误差.在给出误差项后,对误差的产生机理进行了讨论,通过仿真和实测给出了误差对测试结果的影响.     

时域平面近场测量的数值分析方法

本文以H面喇叭为例,研究了天线时域近场的运动状态,用谱域法分析了平面近场分布状况,得出采样原则,为平面近场扫描测量提供了理论依据。介绍了时域平面近场测量的近远场变换公式,包括时域和频域两种计算途径。对各自的优点作出了探讨。运用近远场变换方法计算了时域远场和频域方向图。     

车载天线整车测试系统集成与实现

针对自动驾驶、车联网等新技术场景下汽车天线整车性能测试的新需求,借鉴近年来近场测量技术的研究成果,设计采用半球面近场与平面近场相结合的方式,集成了一套汽车天线整车测试系统.系统基于8 m直径的方位转台实现了中小型汽车的车载天线测试定位,基于12 m直径的弧形多探头采样架实现了 400 MHz～6 GHz工作频段内的车载...     

天线时域近场测量中的时基及幅度修正技术

 在天线时域近场测量中由于脉冲信号源的时基抖动和幅度变化所带来的误差是测量中最主要的误差,其中尤以时基误差最为严重,它使得方向图畸变到了无法容忍的程度.本文即针对此问题提出了天线时域近场测量中的时基及幅度修正技术.该技术在测量通道之外增加了一个参考通道,通过检测参考通道信号提取出脉冲信号源的时基及幅度变化,进而以此修正测量通道的信号.大量的实际测量表明该技术稳定可靠.通过对比试验发现,使用该技术的时域近场测量结果的精度达到甚至优于频域近场测量结果的精度.     

时域近场测试中的采样面截断误差分析与修正

采样面截断误差是影响近场测试结果的一个很重要的因素。本文结合频域近场测量中对采样面截断误差的分析结果,根据时域近场测量的时域近场特性,借助PSTD算法和PML技术,提出一种修正时域近场测量采样面截断误差的新方法,数值例子验证了方法的有效性。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first     

JOURNAL OF ELECTRONICS(CHINA)

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NEXT GENERATION WIRELESS NETWORKS–ESPECIALLY THE USE OF MILLI-MICROWAVE BANDS

The global bandwidth shortage of wireless communications has motivated the exploration of the naillimeter wave （ram-wave） frequency spectrum for the next generation wireless communications. Recent advances in RF CMOS technology and high speed baseband signal processing technologies have enabled tile extensive research and development of turn-wave wireless communications. The multi gigabit per second data rate of ram-wave system will lead to applications in many important scenarios, such as WPAN, WLAN,back-haul for cellular system. And the frequency bands include 28 GHz, 38 GHz, 45GHz, 60GHz, E-BAND and even beyond 100 GHz. The propagation and the imitation of the RF circuits design in these frequency bands make the directional antennas be inevitable for mm-wave communications.