一种具有采样带宽补偿的高性能采样/保持电路

针对中频采样模数装换器中的宽带采样/保持电路,提出了一种新颖的电荷交换补偿（CEC）技术.该技术通过消除采样开关有限导通电阻的影响,补偿了采样带宽,并避免了时钟馈通和电荷注入的加剧.同时设计了具有AB类输出的低功耗两级运放,在1.8V电源下为该采样/保持提供了3V峰-峰值的输入范围.该采样/保持电路在100Ms/s的采样率下,对于200MHz输入信号达到了94dB的无杂散动态范围.在5.5pF的负载下,功耗仅为26mW.     

背入射Al_(0.42)Ga_(0.58)N/Al_(0.40)Ga_(0.60)N异质结p-i-n太阳光盲紫外探测器

在蓝宝石上用MOCVD生长的材料制备了背入射Al0.42Ga0.58N/Al0.40Ga0.60N异质结p-I-n太阳光盲紫外探测器.从器件的正向Ⅰ-Ⅴ特性曲线计算了理想因子n与串联电阻Rs分别为3和93?器件在零偏压下275nm峰值波长处的外量子效率与探测率分别为9%和4.98×1011cm·Hz1/2/W,分析表明Al0.42Ga0.58N窗口层在275nm波长处的透过率仅为15.7%,是器件外量子效率和探测率偏低的原因之一.     

一种有效减缩微带天线RCS的新方法

根据经典理论,对于线极化矩形贴片天线,其主模电场强度在平行于非辐射边的中心线上为零。如果沿此中心线对微带天线加载电阻,对其辐射性能影响不大,然而对散射性能则有很大改善。通过引入一种阻抗加载技术和接地板开槽技术使微带天线的RCS大幅减缩,结合小型化技术,微带天线的RCS得到进一步减缩,而且天线外形尺寸也比原天线有所减小。这样,就同时兼顾了微带天线的辐射性能和散射性能。     

一种新型高精度高温度稳定性恒流源研究

研究一种应用混合集成电路技术实现的新型高精度和高温度稳定性的恒流源,以适应当前系统对恒流源高精度、高温度稳定性和较大电流的需求。在详细分析电路结构和工作原理的基础上,讨论如何提高电路的精度和温度稳定性,并给出具体的解决方案,对关键部分给出了设计电路图,最后对采样电阻的设计和布线艺术给出了合理的方案。投片测试分析表明:该设计安全可靠,达到高温度稳定性和高精度设计目标。该电路具有较小的体积和较好的性能,满足型号系统的要求。灵活的设计方式使其具有较好的使用价值和应用前景。     

应变测量系统误差分析

电阻应变式传感器在实际工程中应用较广。介绍影响电阻应变式传感器精度的一些因素,并对其在实际应用中可能出现的问题进行全面细致的分析。分析电测试验中应变片粘贴质量、非线性及导线长度、温度、不同组桥方式对测试结果所产生的影响,修正了导线电阻引起的误差,大大提高了测量精度,得出了应变电测试试验中减小误差的方法。     

Failure mechanisms of ACF joints under isothermal ageing

The possible failure mechanisms of anisotropic conductive film (ACF) joints under isothermal ageing conditions have been identified through experiments. It has been found that ACF joints formed at higher bonding temperatures can prevent increases in the contact resistance for any ageing temperature. The higher the ageing temperature the higher the electrical failure rate is. The formation of conduction gaps between the conductive particles and the pads and damages to the metal coatings of the particle have been identified as the reasons behind the electrical failures during ageing. In order to understand the mechanism for the formation of the conduction gap and damages in metal coatings during the isothermal ageing, computer modelling has been carried out and the results are discussed extensively. The computer analysis shows that stresses concentrate at the edges of the particle-pad interface, where the adhesive matrix meets the particle. This could lead to subsequent damages and reductions in the adhesion strength in that region and it is possible for the conductive particle to be detached from the pad and the adhesive matrix. It is believed that because of this a conduction gap appears. Furthermore, under thermal loading the thermal expansion of the adhesive matrix squeezes the conductive particle and damages the metal coatings. Experimental evidences support this computational finding. It is, therefore, postulated that if an ACF-based electronic component operates in a high temperature aging condition, its electrical and mechanical functionalities will be at risk.     

Effect of 6 MeV electron irradiation on electrical characteristics of the Au/n-Si/Al Schottky diode

Electron irradiation of the Au/n-Si/Al Schottky diode was performed by using 6 MeV electrons and 3 × 10¹² e⁻/cm² fluency. The current-voltage (I-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) characteristics of the unirradiated and irradiated Schottky diode were analyzed. It was seen that the values of the barrier height, the series resistance, and the ideality factor increased after electron irradiation. However, there was a decrease in the leakage current with electron irradiation. The increase in the barrier height and in the series resistance values was attributed to the dopant deactivation in the near-interface region. The interface states, N_ss, have been decreased significantly after electron irradiation. This was attributed to the decrease in recombination centre and the existence of an interfacial layer. A decrease in the capacitance was observed after electron irradiation. This was attributed to decrease in the net ionized dopant concentration with electron irradiation.     

钒氮合金对激光熔覆钴基合金涂层组织和耐磨性的影响

利用5 kW CO2连续激光,在低碳钢表面熔覆钴基合金和添加钒氮合金的钴基合金涂层.采用光学显微镜(OP)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)研究了熔覆层的显微组织和相结构;利用显微硬度计及滑动磨损试验机测试了熔覆层的硬度和抗磨损性能.结果表明,Co基合金涂层主要组成相为γ-Co与碳化物Cr23C6;加入钒氮合金后,出现了σ-FeV和VN等相,涂层凝固组织明显细化,熔覆层硬度提高,凡界面处硬度均比表层高;熔覆层的耐磨性随钒氮合金的加入及激光扫描速度的增加而提高,同时对熔覆层的磨损机制进行了分析.     

Design and fabrication of multiple-valued multiplexer using negative differential resistance circuits and standard SiGe process

The design of a four-valued multiplexer using the negative differential resistance (NDR) circuit is demonstrated. The NDR circuit used in this work is made of the Si-based metal–oxide–semiconductor field-effect-transistor (MOS) and the SiGe-based heterojunction bipolar transistor (HBT). However we can obtain the NDR characteristic in its combined I–V curve by suitably arranging the MOS parameters. This novel multiplexer is made of MOS–HBT–NDR-based decoders and inverters. The fabrication is based on the standard 0.35 μm SiGe BiCMOS process.     

部分并行软干扰消除迭代多用户检测算法研究

本文提出了一种基于部分并行干扰消除(PPIC)结构的迭代多用户检测算法,并对基于PPIC的迭代多用户检测器的迭代结构进行了改进.由于PPIC多用户检测器前一级输出的信息的准确度会影响到后一级的检测,所以为了提高基于PPIC的迭代多用户检测器的性能,对PPIC每一级的输出信息结合最大后验概率(MAP)信道译码器单独进行迭代处理,这样就提高了PPIC每一级输出的信息的准确性.该迭代结构可用于其他基于PIC型的迭代多用户检测算法.