基于耦合三线结构的宽带功分器研究*

由于传统的威尔金森功分器需要通过多级传输线的级联来拓展其工作带宽,增加了电路设计的复杂度。因此本文提出了一种基于耦合三线的宽带功分器结构。通过在四分之一波长传输线的两端分别引入一节耦合三线,使功分器实现了宽带特性。采用三线耦合器与阻抗变换理论,对影响功分器工作带宽、输入输出端口匹配度和隔离度参数进行了理论分析,并设计制造了基于此结构的宽带功分器。测试结果表明该功分器具有很好的端口匹配、传输损耗和端口隔离特性。     

基于单层超表面的电大尺寸天线阵RCS减缩仿真分析

提出了一种基于单层透波型阻抗超表面(Transparent Resistive Metasurface, TRM)的电大尺寸天线阵RCS减缩方法。该超表面在垂直极化10 GHz处产生低插损透波窗口,而在其他频点和极化条件下作为有耗阻抗表面,天线阵列在带外频段近似全反射,可以作为接地面实现宽带吸波的RCS减缩。采用国产电磁仿真软件EastWave对"电大尺寸+精细结构"的"天线阵+超表面阵列"进行了全波仿真分析,评估单层透波阻抗超表面对电大尺寸天线阵的RCS减缩及辐射性能的影响。仿真结果表明,在天线阵增益损耗小于1 dB条件下实现同极化下带外频段和交叉极化下全频带的宽带吸波,为大型天线阵隐身设计提供了技术支撑。     

基于二维光子晶体的多频段太赫兹波滤波器研究

基于二维光子晶体,提出一种多频段 太赫兹(THz)波滤波器。在光子晶体中引入3条平行的横向波导,通过改变介质柱的半 径或插入半径较小的介质柱在 相邻波导之间构成耦合区域,使特定频率的THz波从中部波导耦合至上、下侧光子晶体波 导并分别从端口2和1输出, 其余的THz波经中部波导从端口3输出,最终达到多频段滤波的效果。利用时域有限差 分法和平面波展开法对所提出 的器件计算和仿真结果显示,频率为f=3.24和3.75THz的THz波分 别从端口1、2和3输出中,传输效率分 别达到95%和99% ,表明本文结构能很好实现多频段滤波效果。     

高选择性透射的双吸收带FSR设计

本文提出了一种带有高选择性透射窗口的双吸收带的频率选择吸波器.该吸波器具有一个可近乎透明传输的通带,并且在这个透射窗口两边分别具有一个高效吸收带,同时对不同非损耗层的设计,该透射窗口可以具备高选择性.此吸波器采取双层平面结构,包括上层的电阻性损耗层和下层的非损耗的带通频率选择表面层,两者的结合就实现了吸波-透射-吸波的...     

多层金属栅网混合结构吸波特性分析

文中采用传输矩阵理论和二端口级联网络分析了多层金属栅网混合结构的吸波特性,通过将多层金属栅网与多层介质阻抗匹配,在介质厚度不变的情况下,明显提高了混合结构的吸收峰值;同时,通过调整每层金属栅网的半径、间距,可调整混合结构吸收峰值位置,给出了典型混合结构的仿真计算结果.结果表明,混合结构吸收峰值可提高6 dB以上,在保证吸收效果的前提下,调整了吸收峰值的位置,可根据要求用于设计不同频段的吸波材料.     

一种基于内匹配器件的功率分配器设计

介绍了一种基于内匹配功率管的Wilkinson微带功率分配器设计新思路。传统Wilkinson微带功率分配器在低频段体积大,用于内匹配功率管时很难在规定的尺寸范围内使用,采用高介电常数陶瓷基片辐射损耗大,直流转换效率低。适当引入不连续性,提高端口阻抗值,端口阻抗引入的虚部参与后续匹配网络的新型Wilkinson微带功率分配器,与传统Wilkinson功率分配器相比,体积更小,效率更高,有很好的实用价值。设计的工作频段在5.2～5.8 GHz的Wilkinson微带功率分配器,在整个频带内输出功率大于50 dBm,饱和功率增益高于7 dB,功率附加效率大于30%。     

一种应用于12 GHz的AlN多层陶瓷外壳

以AlN材料为陶瓷基材,采用陶瓷绝缘子的射频传输端口结构及陶瓷焊球阵列封装形式,结合多层陶瓷加工工艺,设计并制备了一款可封装多个芯片的X波段AlN陶瓷外壳。采用应力仿真软件对外壳进行结构设计,利用电磁仿真软件对该外壳的射频端口进行仿真优化。采用微带线直接穿墙形式,设计了共面波导-带状线-共面波导的射频传输结构,并与陶瓷外壳进行一体化设计和制作。利用GSG探针对外壳样品进行测试,实测结果表明,在0~12 GHz频段内,外壳射频端口的插入损耗不小于-0.5 dB,回波损耗不大于-15 dB,AlN一体化外壳尺寸为10.25 mm×16.25 mm×4 mm,可广泛应用于高频高速信号一体化封装领域。     

电容加载共面波导移相器的损耗特性

借助仿真软件Sonnet研究了金属导电层厚度、电导率和铁电薄膜介质损耗对移相器传输损耗和反射损耗的影响。结果显示:导电层的厚度超过2.0μm后,移相器的传输损耗不再随导电层厚度的增加而改变;随着导电层电导率的增加,移相器的传输损耗在高频段迅速减小;随着铁电薄膜介质损耗的减小,移相器的传输损耗在高频段下降很快;当介质损耗小于0.001时,移相器的传输损耗几乎不再减小。前述三种因素对反射损耗基本无影响。     

地空路径太赫兹波雨天衰减特性分析

雨滴的散射和吸收作用会严重增加地空链路上太赫兹波的传输损耗,降低无线通信的性能。为实现太赫兹波在地空链路上的传输应用,必须对太赫兹波在降雨环境中的传输特性进行深入研究。本文对原有的雨衰模型进行了修正,基于Mie理论,分析了降雨率的变化对地空链路上太赫兹波传输的影响,并与原有模型的计算结果进行了对比。结果表明：在整个太赫兹频段,雨衰减损耗会随降雨率的增加而增大,随频率的增加先增大后减小,且高频太赫兹波段相对0.1～1 THz频段范围的雨衰损耗更小;同时,当频率超过1 THz时,大气窗口越靠近10 THz,损耗越小,在降雨天气环境进行无线通信传输时将更具有通信优势,且频率越低,天顶角越大,模型修正前后的差异性更加明显。     

面向多波段合成孔径雷达天线的大型超宽带拼装式天线罩设计方法

针对特定布局的P波段到Ka波段的多波段合成孔径雷达天线的复杂构型,提出了一种大型超宽带拼装式天线罩的设计方法,能够满足多个不同频段天线大倾角内入射的宽频段高效透波。根据多波段合成孔径雷达天线的不同分布位置和频段,设计相应的不同介电常数组合的多层天线罩结构作为透波区域,并将其拼装为完整的大型天线罩构型。针对原定布局的多波段合成孔径雷达天线在相应工作状态下进行激励,对根据该方法制造的天线罩的透射系数进行测试,结果表明天线罩能够在超宽频带内高效透波,满足实际要求,实现了该布局下的多波段合成孔径雷达天线的大型超宽带拼装式天线罩设计。     

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.