Research on COB De-embedding in Scattering Parameter Measurement

The popular radio frequency (RF) chip on board (COB) test has gradually taken the place of on-wafer test due to the high efficiency and high power. This paper presents the extended Open-Short-Load (OSL) that is one-port calibration method to verify the error model de-embedding in S parameter measurement. Three-level cascade structure on COBs system error model is proposed and analyzed. Four kinds of calibration plane solutions for de-embedding are verified. At last, on-board calibration (CAL) kits solution is established to decrease the system error to the least value. The maximum error shift can be controlled less than 0.1 dB comparing with the on-wafer test results. In general, the practical application results prove that this method is reasonable and effective and easy to be mastered.     

OSL剂量计的性能研究与测量不确定度评定

光致发光(OSL)剂量计是一种被动式累积个人剂量计,用于外照射个人剂量监测。与热释光剂量计(TLD)相比,它具有可重复测量、环境稳定性好、使用寿命长、信号衰退慢等优点。本文结合在个人剂量监测中应用OSL剂量计的工作经验,以OSL剂量计性能实验研究结果为基础,评价了OSL剂量计的最低可探测水平、角响应、能量响应、线性响应,并对OSL个人剂量测量系统的测量不确定度进行了评价。评价结果表明,在中国原子能科学研究院场区,OSL剂量计在1个月监测周期内的最低可探测水平(MDL)为0.04 mSv,角响应、能量响应、线性响应引起的偏差分别是1%、-14%、-4%。在95%的置信水平下,相对扩展不确定度为11.4%。     

锗硅器件高频噪声的去嵌算法研究

提出了一种"开路-直通"的级联结构的二端口网络的晶体管高频噪声去嵌结构以及与此相关的基于噪声相关性矩阵的去嵌方法。和传统的需要配备两个"直通"结构的方法相比较,该结构及方法在版图配合的基础上,只需要使用一个"开路"结构和一个"直通"结构,而且多个不同尺寸的被测试器件结构可以共用一个直通去嵌测试结构进行测试及去嵌,结果显示,使用该方法测试及去嵌后的精度几乎不受影响。该方法的意义在于能极大地减少硅片上直通去嵌测试结构的数量从而节省硅片面积;同时,又减少了测试时间、提高了测试效率,极大地降低了成本。     

Optically stimulated luminescence: Searching for new dosimetric materials

Optically stimulated luminescence (OSL) is increasingly being used as a dosimetric technique in various fields such as medical, environmental and space dosimetry, and sediment and archaeological dating. Nevertheless few compounds are suitable as OSL materials. In this work, a survey was made of various insulators, searching for candidates for new OSL dosimeters. Natural and synthetic crystals and glasses from numerous sources are included. Luminescence was stimulated with blue LEDs (470 nm) and with IR laser (830 nm) provided by an automatic reader. Irradiation was performed with a ⁹⁰Sr/⁹⁰Y beta source, and the emitted light was measured with a photomultiplier tube, protected with suitable optical filters. Thermoluminescence (TL) of the samples was also measured, with the same equipment, to evaluate the thermal and optical stability of the defects related to OSL and TL. Among the various investigated materials, Al₂O₃:Cr, Mg, Fe, MgAl₂O₄ spinels, Mg₂SiO₄:Tb, and natural fluorite show potential as OSL dosimeters. Some materials, as barium aluminoborate glasses, although showing intense OSL signals, present a high fading at room temperature. In that situation the OSL signal is related to low temperature TL peaks that also fade at room temperature. None of the investigated materials was specially prepared to be used as an OSL dosimeter, which means that work can be done, mainly in the impurity nature and content, in order to improve OSL signals and to overcome some of the shortcomings that were noticed.     

用高速光器件分析仪测试高增益CATV光站

介绍了使用安捷伦50Ω高速光器件分析仪测试75Ω高增益CATV接收光站的原理和方法。着重解决了测试过程中遇到的测试设备与被测产品阻抗不匹配问题和被测产品增益过高问题。对于阻抗不匹配问题,采用光器件分析仪的去嵌入功能实现50Ω和75Ω间的匹配;对于增益过高问题,采用降低光器件分析仪的光调制度方法来降低光站增益。从实验结果分析,两种解决方法完全可行,并且不会引入测试误差。     

An accurate and simplified small signal parameter extraction method for GaN HEMT

In this paper, development of a small signal model for 2 × 200 μm GaN HEMT based on the conventional 20-element model is presented. The proposed model presents a direct parameter extraction algorithm, instead of the hybrid optimization approach, that provides simplification, accuracy, and less computational complexity. The extrinsic elements are extracted using a modified cold pinch-off condition while discarding the unwanted forward biasing of the gate. The negative drain to source capacitance C_ds is also observed in the ohmic region (for smaller V_DS). An excellent agreement found between the measured and modeled data for a wide range of frequencies and bias values shows the effectiveness of the proposed approach. The proposed modeling technique is validated with a good agreement between the achieved bias dependency of intrinsic parameter values and the respective theoretical parameter values.     

基于非精确计算模型的OSL算法

目的研究多处理机系统任务分配的启发式策略和容错调度算法,设计一种高效实时调度算法．方法只对任务强制部分进行复制,将任务分为强制执行部分主版本PTMi、强制执行部分副版本BkMi．和选择执行部分Oi,采用可选择部分后调度．结果提出了可选择部分后调度（Optional Scheduling Later,OSL）算法,通过实例与ICDM算法进行了仿真比较,说明了该算法的有效性．结论该算法使任务的完成时间提前,提高了处理机的利用率,便于广泛应用．     

微波射频差分探针去嵌入理论研究

为了获得被测件(DUT)准确的散射参数(S参数),研究了用于差分网络的去嵌入理论。在经典的差分探针结构的基础上,提出了一种可以抑制差分测试中共模信号影响的新型差分探针模型,即信号-信号探针(SS探针)。并完成了直通-反射-传输线(TRL)校准件和DUT的设计,推导了差分网络的多模去嵌入理论,编写算法并利用测试数据进行计算,仿真与测试结果表明在0~8 GHz的频率范围内,去嵌入后的散射参数的幅度、相位与仿真结果一致性较好。     

乌海盆地内末次冰期砂楔/冰楔铸型的发现及古气候意义

砂楔/冰楔铸型等具有定量古环境意义的冰缘现象在中国北方已有多处报道,但多集中在末次冰期晚冰阶。报道了首次发现于乌海盆地的冰缘现象,从楔体形态特征、填充物粒度特征和光释光测年等方面对其成因和发育年代进行了深入研究。楔体和填充物剖面穿插关系、物质组成和形态特征分析等指示其形成过程大致可分为两个阶段:早期原生砂楔发育与楔壁近平行的充填-挤压构造;晚期冰楔铸型(包括冰楔形成、融化和填充)在砂楔之上进行叠加。冰楔切穿早期砂楔,导致楔壁物质发生强烈挤压变形,结构扰动,楔体表现为弯曲的不规则形态。光释光测年结果显示,原生砂楔发育的年代主要集中在(62.69±6.81)~(66.45±7.08)ka B.P.,即末次冰期早冰阶,对应于MIS4阶段,并可能部分延续至MIS3b阶段;冰楔铸型填充物年代为(5.95±0.61)~(6.62±0.73)ka B.P.,对应于全新世中期。由于冰楔铸型的填充晚于冰楔发育年代,推测冰楔发育年代可能为末次冰期晚冰阶。基于砂楔/冰楔铸型的发育过程及对环境条件的要求,初步估算出砂楔和冰楔发育时期年均气温比现在低12.1 ℃~13.6 ℃,砂楔发育时期(即末次冰期早冰阶)年降水量与现在相当。乌海盆地砂楔/冰楔铸型的发现为研究中国北方末次冰期尤其是末次冰期早冰阶纬度多年冻土分布及古气候环境提供了新的依据。     

混合平衡-非平衡射频探针的在片测试方法

随着对微波单片集成电路(MMIC)愈发严苛的尺寸限制和集成度要求,越来越多的MMIC芯片如限幅器、射频开关等同时具有平衡和非平衡的不同测试焊盘结构,需采用平衡-非平衡混合射频探针进行在片测试,而基于单一平衡或非平衡结构的直通在片校准件无法同时满足混合射频探针的阻抗匹配要求,导致校准精度大幅下降,无法用于MMIC在片测试.为此,本文对采用传统SOLR校准方式的平衡-非平衡混合射频探针测试的校准误差进行了评估计算,并结合带误差修正的OSL二阶去嵌技术和级联矩阵变换技术,提出一种基于平衡-非平衡混合射频探针的MMIC在片测试方法,同时搭建了以矢量网络分析仪、SG与GSG射频探针、微波探针台等组成的在片测试系统来验证方案可行性.通过矢量修正和级联矩阵去嵌,将校准参考平面精确平移至探针尖端面,有效地保证了测试精度,并且结合C#面向对象语言为该测试方案构建了自动测试系统,实现了仪器控制、数据采集、结果修正、数据分析等全自动操作,避免了人为干预的影响,解决了晶圆级测试面临的效率问题.