S波段空管雷达2. 2 kW固态功放组件的设计

与传统功放组件的设计不同,空管雷达功放组件具有高功率、智能化的特点.文中以空管雷达功放组件的设计为例,论述了发射链路设计、BITE功能设计、冷却设计、结构技术、电磁兼容性设计等设计中的关键问题.提供了一些解决方法,并已在空管雷达发射机中使用,具有广阔的工程应用前景.     

固态发射机BIT系统设计

论述了固态发射机的类型以及 BIT(Built In Test)技术的必要性、雷达总体对发射机 BIT系统的要求 ,并详细介绍了一有源相控阵雷达固态发射机的 BIT系统设计     

L波段大功率固态发射机的研制

简要说明了雷达固态发射机的基本组成,着重介绍了L波段大功率固态发射机的主要技术性能指标、电路形式、设计方法、关键工艺和关键技术。通过对研制的L波段大功率固态发射机样机进行测试,结果表明：该L波段大功率固态发射机实测各项指标达到设计任务书的要求,其主要技术性能指标已达到和部分超过了当前国外同类固态发射机的先进水平,在目前国内同类固态发射机中处于领先地位。     

AN/SPS-40型雷达250千瓦固态发射机

一、引言在过去十年里,固态雷达发射机的性能和成本,在与其他雷达发射机竞争的结果表明:至少在整个L波段频率上,目前设计的某些新型雷达系统和某些改进型的雷达系统中,采用固态雷达发射机是相当普遍的。这种固态发射机技术的发展,在极大程度上受到微波双极晶     

一种L 波段40 kW 固态发射机的设计

介绍了一种L 波段40 kW 固态发射机的系统设计,阐述了发射机射频链路、监控保护等各部分的设计特点和实现方法,介绍了针对航管雷达高可靠性的使用要求所采用的技术,以及解决发射机监控系统电磁干扰等问题所采取的措施。该发射机的成功研制,可为后续新一代航管一次雷达固态发射机设计提供参考。     

L波段全液冷固态发射机设计

介绍新研制成功的应用在相控阵雷达的全液冷固态发射机.对本发射机系统组成与工作原理进行剖析,对采用的模块化设计技术、电磁兼容技术、液冷热设计等技术都做了重点介绍.测试表明:该发射机能很好的满足指标.     

固态军用雷达的优点(上)

一、引言我们已习惯把采用固态发射机(用半导体器件作发射机的射频功率输出器件)的雷达叫固态雷达。1978年11月美国微波杂志刊载的Thomas E. Walsh叙述军用雷达系统的历史、现状和未来展望的文章中,把三座标雷达AN/TPS-59的固态发射机列为雷达技术发展史上的一个里程碑。确实,70年代军用固态雷达技术有了突破性的进展,以致对下一代雷达装备的体制与性能都会有很大的影响。     

多功能固态发射机的一体化设计

介绍了一种多功能固态发射机,讨论了固态发射机的多种功能要求,发射机的不同方案,发射组件的组成、工作原理以及发射机的技术难点等.有源相控阵雷达天线的发射低副瓣是该发射机的显著特点;采用分布式发射组件的幅度加权技术可以实现发射低副瓣.为了融合发射机的多种功能,重点讨论了一体化发射机研制过程中需要解决的一系列工程技术问题.最后给出了比较满意的实验结果.     

大功率GaAs FET偏置电路设计中的有关问题

现代雷达的发展方向是多功能化、小型化,固态发射机以工作寿命长、可靠性高、体积小等优点被广泛使用.本文主要总结了固态发射机设计中部分大功率GaAs FET偏置电路的设计经验.     

S波段全液冷固态发射机设计

介绍新研制成功的应用在相控阵雷达的全液冷固态发射机。分析了本发射机系统组成与工作原理,重点介绍了采用的监控设计技术、电磁兼容技术、液冷热设计等技术。测试表明,该发射机能很好地满足各项技术指标的要求。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.