用OSRC—MM分析存在导电球时的线天线问题

本文利用矢量表面辐射条件（ＶＯＳＲＣ）和矩量法（ＭＭ）分析了导电圆球存在时线天线的性能。计算结果与应用广义多极子技术（ＧＭＴ）计算得到的结果吻合良好。     

a—Si TFT中钼与非晶硅之间的互作用

本文报导当在室温下向非晶硅（ａ－Ｓｉ）表面溅射钼（Ｍｏ）的过程中Ｍｏ与非晶硅发生互作用的现象。该互作用要求一定的临界溅射功率与钼层厚度。其作用速率在ａ－Ｓｉ界面为反应速率限制,而在与Ｍｏ交界面则为扩建速率限制。互作用生成非晶态钼硅Ｍｏ：ａ－Ｓｉ合金。它可阻止铝（Ａｌ）向ａ－Ｓｉ中扩散,同时可改善ａ－Ｓｉ ＴＦＴ的接触特性。当用Ａｌ／Ｍｏ作ａ－Ｓｉ薄膜晶体管（ａ－Ｓｉ ＴＦＴ）的源和漏电极时,可提高     

HDTV信号/SDTV信号转换器

美国Ｓａｒｎｏｆｆ公司设计出的ＡＴｈＣ／ＮＴＳＣ转换器,其目的是便于接收北美地面数字电视（ＤｒＦＶ）广播。此设计能下变频接收到高清晰度电视（ＨＤＴＶ）广播信号,并作为标准４８０扫描线标准清晰度电视（ＳＤＴＶ）信号输出。基准设计的硬件结构如下：主要芯片由美国摩托罗拉公司制造,解调ＩＣ为ＭＣＴ２１００,ＭＰＥＧ解码ＩＣ是ＭＣＴ４０００,微处理器为ＭＣＰ８２３。要接收美国最大的数字卫星广播电台──ＤｉｒｅｃＴＶ的信号。ＭＣＴ４１００也可用作ＭＰＥＧ视频解码ＩＣ。除此之外,还要ＭＣ９２３１７作９０相移键…     

UMTS——第三代移动电话网方案

主要电信运营商阿尔卡特、Ｂｏｓｃｈ、Ｉｔａｌｔｅｌ、摩托罗拉、北电和西门子已宣布他们支持第三代移动电话网———通用移动通信系统（ＵＭＴＳ）的一个解决方案,这种ＵＭＴＳ方案组合了ＴＤＭＡ（时分多址）和ＣＤＭＡ（码分多址）技术的优点。在塞浦路斯岛召开的ＧＳＭ-ＭｏＵ（ＧＳＭ协商备忘录）会议上,电信运营商讨论了已由ＥＴＳＩ（欧洲电信标准协会）讨论过的这些标准的目前提案。这种ＧＳＭ１８００／１９００ＭＨｚ频段范围和新的２ＧＨｚ频带都可部署的组合方法,不仅给现有经营者提供投资保护,同时也给新经营者提供巨大的市…     

新品发布

多模ＭＴ－ＲＪ收发器 Ｔｙｃｏ　查询号 １８１ 泰科电子公司（Ｔｙｃｏ Ｅｌｅｃｔｒｏｎｉｃｓ）日前宣布推出ＡＭＰ ＥＳＣＯＮ多模ＭＴ－ＲＪ收发器,其数据传输速率高达２００Ｍｂ／ｓ。该产品用于ＥＳＣＯＮ链路,可适用于广泛应用的ＭＴ－ＲＪ小型封装模块（ＳＦＦ）连接器接口。这种ＳＦＦ收发器采用２ｘ５ＤＩＰ（双列直插式组件）式封装,集成了ＭＴ－ＲＪ连接器接口。新式小型封装模块的接口宽度大约仅为双工ＳＣ１ｘ９模块的一半,因而设计人员可将给定产品的端口密度提高两倍。 机顶盒 Ｍｏｔｏｒｏｌａ　查询号 １８２ 摩托…     

光纤CATV系统和光调制度

光纤ＣＡＴＶ系统的一个主要设备是ＡＭ光发送、接收端机。本文从分析ＡＭ光发送、接收端机的内部机理出发，说明了一个重要的内部参数－光调制度，它与光纤ＣＡＴＶ系统的性能指标ＣＮＲ（载噪比）、ＣＴＢ（组合三次差拍）、ＣＳＯ（组合二次差拍）等的关系，再从内部参数转为频道数与ＣＮＲ、ＣＴＢ、ＣＳＯ等的关系。为实际光纤ＣＡＴＶ系统设计给出了一个理论依据。本文同时出讲述了光调制度的控制方法、具体测量方法，以及ＡＭ     

环球了望

·日本ＮＥＣ公司与中国信息产业部（ＭＩＩ）电信传输研究所联合宣布,将进行３Ｇ Ｗ－ＣＤＭＡ蜂窝技术试验。ＮＥＣ计划通过建立战略联盟和营销,扩大在中国下一代移动业务中的市场占有率。 ＮＥＣ公司曾参与日本ＮＴＴ ＤｏＣｏＭｏ的Ｗ－ＣＤＭＡ开发工作,其Ｗ－ＣＤＭＡ网络系统和手机为ＮＴＴＤｏＣｏＭｏ商用移动网选用。ＮＥＣ还与英国ＢＴ、泰国ＴＯＴ、韩国 ＳＫ、新加坡 ＳｉｎｇＴｅｌ以及意大利 ＴＩＭ公司就 Ｗ－ＣＤＭＡ技术进行了联合试验。 ·也门共和国总统Ｓａｌｅｈ出席了华为技术有限公司和也门电信合作的国家主干传…     

新品橱窗

ＣｏＳｉｎｅ 公司最新 ＩＰＳＧＴＭ业务处理器全面上市 ＣｏＳｉｎｅ Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ近日宣布,全新的ＳＨＡＲＣ业务处理器从即日起全面上市,该产品已被命名为ＩＰＳＧＴＭ业务处理器。ＩＰＳＧ是ＩＰＳＸ ３５００ＴＭ和ＩＰＳＸ ９５００ＴＭ处理交换机的一种独立的子系统,利用ＩＰＳＧ业务处理器,运营商能够为用户提供以计算为主的网络服务,传输速度可以达到几个ＧＢ,如防火墙、ＭＰＬＳ／ＩＰ安全ＶＰＮ （ＩＰＳｅｃＶＰＮ）、帧中继集成服务、ＤＳＬ聚合等。 安德鲁推出防火型ＨＥＬＩＡＸＲ微型电缆 安德鲁公…     

INFORMATION FOR AUTHORS

ＩＮＦＯＲＭＡＴＩＯＮＦＯＲＡＵＴＨＯＲＳ￥／／ＳＥＭＩＣＯＮＤＵＣＴＯＲＰＨＯＴＯＮＩＣＳＡＮＤＴＥＣＨＮＯＬＯＧＹ（ＳＰＡＴ）ｉｓｐｕｂｌｉｓｈｅｄｑｕａｒｔｅｒｌｙｗｉｔｈｔｈｅｐｕｒｐｏｓｅｏｆｐｒｏｖｉｄｉｎｇｔｈｅｐｕｂｌｉｃａｔｉｏｎｏ...     

第三代全球卫星移动通信系统在欧洲研究的进展

总结了欧盟“先进的通信技术与业务（ＡＣＴＳ）计划”在全球卫星移动通信方面研究的进展，介绍了ＩＮＳＵＲＥＤ、ＮＥＷＴＳＥＴ、ＳＥＣＯＭＳ、ＳＩＮＵＳ、ＴＯＭＡＳ工程在网络集成、空中接口、移动终端等方面取得的成果，认为卫星移动通信在未来的全球移动通信系统（ＵＭＴＳ）中占有重要的地位。     

遗传算法在和差波束印刷天线中的应用

讨论比较了四种现代化方法的基本原理和内容，据此选择遗传算法建立了一种耦合渐变槽线天线的多目标优化模型，用于设计单脉冲系统的和差波束印刷天线，详细讨论了应用遗传算法的具体步骤，经计算得出的天线性能达到了预期的优化目标，并得到实测数据的验证。     

Collision avoidance slot allocation scheme for multi-cluster wireless sensor networks

This paper introduces a collision avoidance slot allocation scheme for Time Division Multiple Access (TDMA) based Medium Access Control (MAC) in multi-cluster wireless sensor networks. TDMA MAC protocols have built-in active-sleep duty cycle that can be leveraged for limiting idle listening. Also, they can overcome the overhearing problem, thus have better energy efficiency. Enabling concurrent intra-cluster communications using a single radio channel is a key issue in TDMA MAC protocols. Using orthogonal frequency channels or different Code Division Multiple Access codes for different adjacent clusters can solve the problem at the expense of cost. In this paper, we propose a new distributed slot allocation protocol called  Coordinated   Time   Slot   Allocation (CTSA) that can reduce collisions significantly using a single radio channel. We use simulations to study the effects of different system parameters on the performance of our proposed protocol. Simulation results show that applying CTSA over clustering protocols can significantly reduce collisions. It also shows fast convergence for our proposed CTSA protocol. In this paper we apply our CTSA scheme to the Low Energy Adaptive Clustering Hierarchy protocol which forms the basis for many cluster based routing protocols. CTSA is also compared with the SRSA algorithm proposed by Wu and Biswas (Wirel Netw 13(5):691–703, 2007) by means of simulation.     

一种能产生针状波束和扇形波束的面天线

本文设计出了一种既能产生针状波束又能产生扇形波束的新型面天线,该天线的增益和方向图通过理论计算计算出来。本文设计实例中的面天线的针状波束的E、H平面的半功率宽度分别为2.320、2.240,而扇形波束的E、H平面的半功率宽度分别为2.010,6.40。     

基于缝隙单元的3D多模频率选择结构研究

为了实现高性能的滤波响应,提出了一类新型基于缝隙单元的三维多模频率选择结构。首先以传统2D“十字”缝隙型频率选择表面及其级联结构为例,阐述了2D频率选择表面在结构、性能上的优缺点。为了进一步改善滤波性能,分别提出了基于均匀缝隙单元、阶梯阻抗缝隙单元、多模吸波式缝隙单元的3D频率选择结构。该类型频率选择结构可基于传输线理论进行分析,在设计频段内可产生多个谐振模式而展现出高性能滤波响应,故在微波毫米波频段具有良好的应用前景。     

Wideband Hybrid Array Concept for Millimeter-wave Applications

The use of circular waveguide radiators electromagnetically coupled to a stripline distribution network is proposed in this work as wideband hybrid array configuration suitable for millimeter-wave applications. The adopted excitation mechanism avoids the use of transition components from stripline to radiators, which are responsible for loss mechanisms affecting similar configurations in literature. The effectiveness of the hybrid approach is first validated on a reduced frequency X-band prototype. Then, a Ka-band array design is presented and experimentally tested to prove the wideband radiation behavior. A radiation efficiency of about 60 percent is also demonstrated on the Ka-band prototype.     

具有带通响应的槽线微波功分器

首次提出一种基于半波长槽线谐振器的功分器。该功分器集合了功率分配、带通响应这两种功能于一身,实现了电路设计的多功能化和小型化。该功分器的仿真和测试结果吻合良好,在通带内功分器的两个输出端口3dB等分同时插入损耗小于2dB。区别于传统功分器的是,该功分器两个输出端口的在基波同相,而在二次谐波处为反相信号。这个特点在微波非线性电路的功率合成过程中可用来抑制二次谐波。     

Improved formulae for the resonant frequencies of triangular microstrip patch antennas

In this article, an improved formula for the effective side length (a _eff) of the equilateral triangular patch antenna is presented. The computed resonant frequencies for the first five modes, using this formula, are compared with the available experimental and theoretical results in the literature. It is shown that the proposed formula has better accuracy than other available expressions. Moreover, the 30°–60°–90° and 30°–30°–120° triangular patch antennas are studied. Specifically, improved formulae for the effective dielectric constant of these patches are derived.     

Triangular quad-port multi-polarized UWB MIMO antenna with enhanced isolation using neutralization ring

In this study, a quad-port multi-polarized ultra-wideband (UWB) multiple input multiple output (MIMO) antenna system with a new isolation technique is designed for wireless devices. The antenna structure consists of four triangular monopole elements and neutralization ring (NR) structures. The monopoles are back-to-back positioned in symmetrical and orthogonal arrangement. Therefore, they radiate towards four directions without interference, and thus the diversity performance is improved. A novel NR is formed by combining a rectangular ring and a straight line to reduce the mutual coupling due to interoperation of the elements. Each triangular monopole is fed by 50 Ohm microstrip transmission line (MTL) with a thin strip line for ensuring impedance matching. Antenna performance in terms of impedance bandwidth, current distribution, radiation pattern, peak gain and envelope correlation coefficient (ECC) is also investigated. The MIMO antenna system has 3.1–17.3 GHz impedance bandwidth, 1–5 dBi peak gain variation, less than 0.1 ECC. The results indicate that the proposed antenna has the characteristics of larger UWB bandwidth, high isolation by the NR structure, multi-polarization, uniform gain and quasi-omnidirectional pattern.     

Sum/difference beam duplexer for coupled tapered slot-line antenna

A successful design for a sum/difference beam duplexer used as the feed network of a coupled tapered slot-line antenna (CTSA) is presented. VSWR/spl les/1.5:1 was obtained at both the sum and difference ports over the 33.4-36.0 GHz frequency range. An isolation of -25.0 dB was obtained between the sum and difference ports over the range 33.2-37.6 GHz.     

印刷环天线的谐振特性

本文基于环形几何上的超二次曲线表示,分析一组印刷环天线的谐振特性,首先给出求解天线电流分布和辐射场的统一数值计算公式,然后通过改变超二次曲线的开头参数,分析印刷在不同介质基片上环形天线的形状与其谐振电阻和谐振环周长的关系。结果表明,可以通过调整环形天线的几何形状获得与馈线相匹配的谐振电阻。