高功率超宽带电磁脉冲技术

高功率超宽带电磁脉冲源对许多应用 ,如冲击脉冲雷达、探测地雷、微波武器等是十分重要的。本文评述在快速高压开关和超宽带天线发展中的最新进展 ,讨论了未来这类超宽带源研究的技术挑战和发展前景     

5G天线对典型强电磁脉冲响应的对比分析

针对强电磁脉冲环境对5G通信系统的威胁,以5G天线为例,研究了典型电磁脉冲经天线口面耦合进入天线端口的电磁脉冲能量大小。利用电磁仿真软件分析了微带天线单元在高空核爆电磁脉冲、高功率微波以及超宽带电磁脉冲环境下天线馈电端口处感应的瞬态电压的时域和频域特性。仿真结果表明:高功率微波和超宽带电磁脉冲在天线单元馈电端口的感应电压较大,极易干扰甚至毁伤5G通信系统的射频后端。     

超宽带纳秒脉冲在带通滤波器中传输特性研究

根据超宽带(UWB)纳秒电磁脉冲的基本特性,采用模拟计算仿真与实验研究方法,研究了超宽带纳秒电磁脉冲信号通过微波接收机带通滤波器的时域、频域传输特性,初步认识了超宽带纳秒电磁脉冲通过带通滤波器传输特性规律,它是对传统连续波(CW)信号与脉冲调制信号通过微波带通滤波器传输特性技术的补充和完善。该研究成果为将来开发超宽带纳秒电磁脉冲在各类接收机中的应用提供技术基础。     

电磁脉冲在地下的传播特性研究

对于电磁脉冲的传播来说,大地是一道天然的障碍,因此研究电磁脉冲在地下的传播规律,并将其用于线路和设备的抗电磁干扰,是很有意义的。本文分析了HEMP电场在地下的传播规律,并比较了HEMP和雷电磁脉冲(LEMP)、超宽带电磁脉冲(UWB EMP)在地下的传播情况,比较了HEMP在地下和地上的传播情况,结果表明:高频电磁脉冲电场在地中随深度增加而快速减小,低频电磁脉冲变化较小;高频电磁脉冲电场随大地电导率减小而增大、脉宽变宽,随大地介电常数增大而减小,随入射波极化角和方位角增大而减小,随俯仰角增大而增大。然后,根据电磁脉冲在地下的传播规律提出了电磁防护措施和建议。本文的研究有利于指导地下设备的电磁防护设计。     

半导体电磁防护限幅器的发展

当前电磁环境日趋复杂,超宽带、高功率等强电磁技术已经成熟,对信息化装备构成了越来越严重的威胁,限幅器的应用需求越发迫切。文章从半导体限幅器的防护原理及电路结构入手,结合电磁脉冲防护及高功率微波防护的典型应用,详细介绍了电磁防护限幅器的技术路线,对比了Si、GaAs限幅器的特性,指出兼具Si及GaAs限幅器优势的高频、低插损、耐高功率GaN限幅器将是未来电磁防护限幅器的发展趋势。     

一个微波小型化超宽带高功率分配网络

为了实现微波功率分配领域对超宽带和高功率的双重应用需求,本文呈现了一个小型化超宽带高功率的悬置带线四路功率分配网络。它采用了一种超宽带功率分配结构,避免了传统Wilkinson电路带宽限制,并结合了低阻抗集成传输线的高功率容量的特点,具有小型化、超宽带、高功率、低插损的特点。仿真设计结果表明：在2-18GHz频段内,该结构的插入损耗小于0.6dB,回波损耗优于9.5dB（在2.75-18GHz内回波损耗优于15dB）,端口幅度差小于0.1dB,相位差小于1度。     

高速高功率半导体开关DSRD特性浅析

漂移阶跃恢复二极管（DSRD）是一种先进的全固态、高速、高功率半导体断路开关,是超宽带、高功率脉冲信号源的关键部件。对DSRD的工作原理和典型应用电路以及DSRD在纳秒级高功率脉冲发生器方面的应用做了介绍。DSRD的这些优点使其在超宽带和高功率微波等方面有广阔的应用前景。     

基于正向建模的目标超宽带电磁脉冲雷达回波仿真

为了快速获取超宽带（ultra-wideband,UWB）电磁脉冲激励下雷达目标的时域电磁响应,提出了一种基于散射中心正向建模的目标时域回波仿真方法.从目标几何模型出发,利用空间射线分集技术对强散射源进行分离,通过模型参数正向确定方法构建出目标的属性散射中心模型,用以表征目标高频电磁散射特性,并在UWB电磁脉冲激励下进行仿真运算,获得目标时域回波信号.以典型目标SLICY为例,基于正向建模的散射中心模型,快速获取不同UWB电磁脉冲激励下的雷达回波信号,与高频仿真方法得到的一维距离像（high resolution radar profile,HRRP）进行对比分析,吻合良好.由此验证了本文提出的回波仿真方法的有效性,为不同辐射源激励下目标的快速电磁响应研究提供了一种新思路.     

Marx同步性问题及多支路解决方案分析

Marx脉冲发生器是超宽带高功率微波发生器的关键技术之一,根据对该技术中传输路径上火花开关的逐级过压特性的分析,指出导致Marx电路同步性问题存在的原因,并给出多充电支路的解决方案,同时在对不同电路结构充电方式的波形详细分析的基础上比较了它们的各自特点。最后,将多支路充电方法应用于Marx高功率电磁脉冲发生器试验装置。自制试验装置提供的试验结果与本文理论分析相吻合。     

新器件雷达发射机技术的研究

对能够产生极窄脉冲、高功率的半导体器件进行理论研究和分析，并在此半导体器件的基础上组成大功率超宽谱脉冲相干信号源。分析相干超宽带信号在超宽谱雷达(UWB)和高功率微波武器(HPM)中的应用。     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

Emerging interconnects: a state-of-the-art review and emerging solutions

Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years.     

Photonic generation of ultrawideband signals using a delay interferometer

We demonstrate a novel scheme to generate ultrawideband (UWB) monocycle and doublet pulses byinputting a dark return-to-zero (RZ) signal into a delay interferometer (DI), which accords with the general features in future applied UWB system, namely, single optical source input, simple configuration and passive device. The two polarized interferential beams have a time delay and a phase difference when they propagate through the DI. By adjusting polarization controllers (PCs), the total phase difference, i.e., the sum of the relative opticalphase difference between two orthogonally polarized components caused by PCs and the optical-phase shift due to birefringence of the polarization-maintaining fiber (PMF), the orientation angle of the polarization beamsplitter (PBS) relative to the two axes of the PMF are able to be changed and controlled. When the appropriate conditions are met, UWB monocycle and doublet pulses are generated conveniently.     

石墨烯基电子学研究进展

综述了石墨烯晶体的能带结构和独特的电子性质,如双极性电场效应、单双层石墨烯效应、衬底效应、石墨烯纳米带(GNR)带隙等特殊效应的研究现状。介绍了石墨剥落技术、外延生长和化学气相淀积(CVD)等石墨烯材料的制备以及表征方法。列举了石墨烯在电子、显示、太阳电池、传感器和氢存储等方面的应用,如在石墨烯场效应管、石墨烯纳米带场效应管(SET)、石墨烯单电子晶体管、石墨烯金属晶体管、石墨烯基纳米电子机械系统(NEMS)、石墨烯分子开关以及石墨烯基高电子迁移率晶体管(HEMT)制备方面的应用。人们已经研究出不同栅长的n/p型顶栅石墨烯场效应管(GFET),并采用标准的S参数直接表征器件的高频性能。理论和实验表明,所有石墨烯纳米带场效应管(GNRFET)在室温下工作的前提是GNR的带宽尺寸小于10nm,并具有半导体场效应管的性能。     

在银胶体系中罗丹明B单分子水平上拉曼光谱研究

采用表面增强托曼散射（SERS）技术,比较了单分子水平上银胶纳米体系中罗丹明B（RhB）浓度为10^-11mol／L以下的拉曼光谱和通常单分子水平上罗丹明6G（Rh6G）浓度在10^-11mol／L的拉曼光谱,无论自由沉积在玻璃表面还是在液体环境下的结果显示,单分子水平上Rh B的拉曼光谱灵敏度是Rh 6G的2倍多。因此,利用RhB作为探测试剂将能够提供更加丰富的信息,这对单分子的光谱研究以及高灵敏度探测试剂的应用研究具有重要的意义。     

OBIST methodology incorporating modified sensitivity of pulses for active analogue filter components

In this paper, oscillation-based built-in self-test method is used to diagnose catastrophic and parametric faults in integrated circuits. Sallen–Key low pass filter and high pass filter circuits with different gains are used to investigate defects. Variation in seven parameters of operational amplifier (OP-AMP) like gain, input impedance, output impedance, slew rate, input bias current, input offset current, input offset voltage and catastrophic as well as parametric defects in components outside OP-AMP are introduced in the circuit and simulation results are analysed. Oscillator output signal is converted to pulses which are used to generate a signature of the circuit. The signature and pulse count changes with the type of fault present in the circuit under test (CUT). The change in oscillation frequency is observed for fault detection. Designer has flexibility to predefine tolerance band of cut-off frequency and range of pulses for which circuit should be accepted. The fault coverage depends upon the required tolerance band of the CUT. We propose a modification of sensitivity of parameter (pulses) to avoid test escape and enhance yield. Result shows that the method provides 100% fault coverage for catastrophic faults.     

乘积合并接收的差分跳频通信系统在瑞利衰落信道上抗部分频带干扰的性能分析

该文介绍了一种新型短波跳频通信技术--差分跳频,频率转移函数设计和信号的检测方法是差分跳频中的关键技术.在瑞利衰落信道上,在有部分频带干扰和加性高斯白噪声共存的条件下,采用乘积合并接收的方法,对差分跳频通信系统的误符号性能进行了理论分析,同时做出相应的计算机仿真.结果证实了,在瑞利衰落信道上差分跳频通信系统采用乘积合并接收的方法要比采用线性合并接收的方法具备更好的抗部分频带干扰的性能.     

340 GHz GaN大功率固态倍频链

随着太赫兹技术的应用和发展,对大功率太赫兹固态源的需求愈加迫切。文中基于GaN肖特基二极管(SBD)工艺设计并制造了具有高功率输出的170 GHz和340 GHz太赫兹倍频器,实现了340 GHz大功率太赫兹固态倍频链。采用多管芯GaN SBD提高器件功率承载能力,综合开展电路优化设计提升倍频性能,通过仿真研究和实验测试,验证了倍频器设计的有效性和先进性。170 GHz倍频器的实测峰值输出功率达到580 mW,倍频效率为14.5%。340 GHz倍频器的实测峰值输出功率为66 mW,倍频效率为12.5%。该太赫兹固态倍频链性能优良,在太赫兹系统中具有重要的应用价值。     

An all-optical method of developing data communication system with error detection circuit

The basic criterion of data communication is that received data should exactly be the replica of the transmitting data. If any error is introduced in the received data, then data transmission should be stopped immediately. In this article the authors have developed an all-optical method of data communication system with error detection mechanism that works with frequency encoded data. Basic building blocks of the proposed data communication scheme are parity generator and parity checker which are developed from all optical XOR logic gates. Simulation results testify the feasibility of the proposed scheme. These logic gates are developed exploiting nonlinear polarization rotation based frequency conversion and switching character of semiconductor optical amplifiers. The scheme with frequency encoded data, high speed of frequency conversion and polarization switching action of semiconductor optical amplifier offers secure, error free, faster data communication network.     

光传送网的性能监测方案

在简要回顾传统性能监测方案的基础上,引入了插入型(Intrusive )和非插入型(Non-intru-sive)在线性能监测的分类方式,着重阐述了基于模拟量监测的非插入型光性能监测方案。