CAD OF MILLIMETER WAVE OSCILLATORS WITH THE FDHB TECHNIQUE

In this paper the modelling, analysis and optimization of millimeter wave oscillatorsare investigated by using the a frequency-domain harmonic balance technique (FDHB), where theexternal-circuit impedances looking outside from the active device are calculated with a combinedtechnique of modes expansion, Galerkin, and collocation methods. The optimization results arein agreement with the experimental ones, which show the reliability of the presented model andoptimization.     

一种新颖温敏材料的光纤温度多路测量系统

本文讨论的是一种新颖温敏材料的实用型光纤温度传感器,这种传感器采用了新颖的半导体着色玻璃材料,全玻璃传感探头,在整体设计上采用了双波长误差校正系统,光源及光电检测器恒温系统,有效地减少了漂移,并且由于使用星形光纤耦合器及单片微机系统而提高了整机的性能价格比。     

手写汉字的四角识别方案

手写汉字的本质特征的抽取是提高识别率的关键，而识别规则的生成又依赖于大量样本的归纳学习，手写汉字的四角方案就是针对这两个问题设计并实现的。实验结果证明了该方法的可行性和优越性。     

Simulation and fabrication of submicron channel length DMOStransistors for analog applications

The use of an asymmetric MOS structure for superior analog circuit performance is considered. Results from the fabrication of 1-μm-gate length DMOS transistors show increases of up to 1.9 in transconductance, 10 in output resistance, and 8 in intrinsic gain when compared to NMOS structures of similar gate length and threshold voltage. Substrate current is also reduced by up to a factor of 10. This represents the first reported results of submicron channel length DMOS transistors. The standard 7° implantation angle has significant impact on DMOS fabrication and is shown to produce a usable asymmetric DMOS from an otherwise symmetric DMOS. An optimal implant energy and diffusion time are shown to exist for DMOS enhancement region formation. Two-dimensional process and device simulators have proved necessary to develop the DMOS process, as well as to qualitatively explain body effect reduction and threshold voltage determination. The DMOS process has successfully yielded experimental circuits including a single ended operational amplifier of folded cascode technology and a 101-state ring oscillator     

New method for analysis of electromagnetic coupling to an angled two-strip transmission line

The electromagnetic coupling to an angled two-strip transmission line is analysed to constructing an angled two-plate transmission line equivalent to the original geometry, and then solving the cylindrical transmission line equations of the original source analytically. The results agree with the numerical values of the circuit-concept approach.<>     

High-performance InP/InGaAs heterojunction bipolar transistors with highly carbon-doped base grown by chemical beam epitaxy

InP/In/sub 0.53/Ga/sub 0.47/As heterojunction bipolar transistors (HBTs) using a highly carbon-doped base are reported. High carbon doping has been achieved by chemical beam epitaxy (CBE). The resulting hole concentration in the carbon-doped base is as high as 7*10/sup 19//cm/sup 3/. To the authors' knowledge, this is the highest doping level reported using carbon. HBTs with a 20 AA spacer layer exhibited nearly ideal I-V characteristics with collector and base current ideality factor of 1.018 and 1.037, respectively. Current gain and breakdown voltage BV/sub CEO/ were 7 and 6 V, respectively.<>     

微波器件失效率快速试验方法研究

介绍了微波低噪声GaAs FET恒定应力加速寿命试验结果,沟道温度T_(ch)为145℃时,平均寿命MTTF为9.64×10~6h,最主要的失效模式是源漏饱和电流I_(DSS)退化降低。建立了表征GaAs FET稳定性的敏感参数I_(DSS)的退化模型InP=a+blnt,分析了I_(DSS)退化与温度应力的加速关系。提出了快速推断器件可靠性的建议。     

用于LDD和SST的SiO2边墙干法腐蚀工艺研究

本文从干法腐蚀角度出发,首先从数学上分析了多晶硅角度,SiO_2边墙的宽度和高度,衬底损失与各工艺参数间的关系,指出边墙的宽度和高度分别取决于多晶硅的角度和过腐蚀量。在Tegal1512e设备上,采用Cl_2、SF_6、N_2混合气体,开发了多晶硅干法腐蚀工艺,讨论了LDD的正胶掩膜及SST的SiO_2掩膜对工艺的不同影响。SEM分析发现了SF_6气体腐蚀的各向同性。在Tegal903e设备上,采用CHF_3、SF_6、He混合气体,开发了SiO_2边墙干法腐蚀工艺,研究了腐蚀的各向异性,辐射损伤,选择比,均匀性及重复性的控制方法。取得的工艺结果为,腐蚀速率(?)_(sio_2)≈400nm/min,均匀性U≤±5％,选择比S_(f8)>10,工序能力指数C_p>1。     

Design of optimum signals for the simultaneous estimation of timedelay and Doppler shift

The problem of joint estimation of time delay and Doppler shift is considered from the point of view of the Wigner distribution of the signal. A very efficient method of obtaining the optimum signal with minimum estimation error based on the convexity of the design region is developed. Practical applications, however, require the signal to satisfy other constraints which present complications in acquiring the optimum signal. A design approach based on the method of simulated annealing is suggested to solve for the optimum signal under constraints. The performance of the signals so obtained is evaluated and compared with that of signals obtained by synthesis     

基于ISMC-PSO的风电爬坡输出功率预测系统的研究

目前风电场都是使用单一的功率爬坡预测模型,其泛化能力较差,预测精度低。通过分析支持向量机和极限学习机两种单一功率的爬坡预测模型,研究了这两种模型的权值选取方法,提出了一种组合功率爬坡预测模型。该模型使用基于粒子群算法的改进算法对上述两种单一模型的权值进行权重优化,形成了一种新的高精度的预测系统。然后对该系统进行建模仿真。仿真结果验证了该预测模型的有效性,其预测精度较之单一的预测模型有了很大的提高。