四次谐波镜像抑制混频器中无源部分的设计

本文介绍了四次谐波镜像抑制混频器中无源部分的设计,无源部分包括了双巴伦和兰格电桥。通过ADS 软件进行相关的仿真,最终实现了巴伦在频段7.9~9.5GHz 的幅度不平衡度小于0.2dB,相位不平衡度小于1°,在中心频率8.7GHz 的插损约为7.3 dB;兰格电桥在频段30~40GHz 的幅度不平衡度小于0.3 dB,相位不平衡度小于1°在中心频率35GHz 的插损约为3.25 dB。双巴伦和兰格电桥仿真得到的结果良好,为最终四次谐波镜像抑制混频器的单片实现奠定了基础。     

一种Ka频段功率合成放大器的设计

为了满足系统对发射机小型化的需求,设计了一种Ka频段功率合成放大器,采用波导空间功率合成结合电路功率合成的方式,有效地提高了功率合成放大器的功率密度。吸收传统威尔金森电桥的优点,设计了一种低损耗毫米波微带集成3 d B电桥,其成本低,加工容易,在26~32 GHz插入损耗小于0.3 d B。提出了一种新型的魔T功率合成结构,既保持了较好的3 d B功率分配又提高了两输出支路的隔离度。以此2种3 d B电桥为基础的Ka频段功率合成网络,可提高功率合成放大器工作的稳定性。     

光控相控阵波束接收网络

文中提出了一种基于光纤色散真时延技术的光控相控阵雷达多波束接收网络。该网络制作原理是根据光纤的色散特性,主要由密集波分复用器(DWDM)和光纤延时模块构成。DWDM 实现对多通道光合成,多个光开关和光纤延时环组成的光纤延时模块实现对合成的多路光载波进行延时量调节,从而实现波束扫描。依据原理方案,研制了一套16通道光接收、双波束形成网络,实现从-40°到+45°的16个不同波束指向扫描,切换速度≤30us。暗室测试证明了其波束形成能力。     

并联双晶体高速削波快脉冲源的设计

设计了一种并联双晶体高速快脉冲源,用于激光物理实验中预脉冲的高速削波。该削波脉冲源采用升压工作模式,由光电转换模块、高压电源模块、开关器件及电路等部分组成。光电转换模块将光信号转变为开关通断信号,用于控制高压脉冲输出;集成的高压电源模块和开关器件简化了电路设计,增加了该电源的可靠性;设计合理的开关电路和元件参数,保证稳定输出符合要求的高压脉冲波形。该快脉冲源的输出脉冲幅度大于4 000 V,下降沿小于10 ns,时间抖动小于1 ns,已成功用于激光物理实验预脉冲的削波。     

Ka 波段基波镜像抑制混频器无源电路的设计

本文介绍了Ka 波段基波镜像抑制混频器中无源电路的设计，无源电路包括带直流偏置支路的3dB 同相功分器和带中频输出支路的兰格电桥。运用ADS 软件进行辅助设计，最终得到功分器在频段32~37GHz 的幅度不平衡度小于0.01dB，在中心频率35GHz 的插损约为3.2 dB；兰格电桥在频段32~37GHz 的幅度不平衡度小于0.15 dB，相位差约为85°，相位不平衡度小于0.5°在中心频率35GHz 的插损约为3.4 dB。最终的仿真结果较好地满足了设计要求。     

LTCC基开关驱动低噪放一体化模块设计

基于LTCC技术设计了一款双通道应用的开关、驱动和低噪放一体化模块,利用HFSS对无源器件电感进行仿真,将电感嵌入LTCC基板中,不仅提高了模块的集成度,同时也降低了成本。在1.8~2.1 GHz频段内,ANT-RX通道增益达到23.8 dB,输入驻波比小于1.49,输出驻波比小于1.33,通道隔离大于44 dB,噪声系数小于1.21 dB(含评估板单端损耗约为0.15 dB);ANT-TX通道插入损耗小于0.42 dB(含评估版损耗约0.3 dB),输入输出驻波比均小于1.1。     

一种新型的毫米波功率合成电路

针对毫米波功率合成技术研究,吸取传统W ilk inson电桥的优点,提出了一种新型低损耗毫米波微带集成3dB电桥,其成本低、加工制作容易、在32GHz~37GHz,插损为0.2dB;以此3dB电桥为基础的Ka频段功率合成网络,在频率33~35GHz,合成效率达75%.     

毫米波多功能和差网络设计

设计了一种高集成多功能有源和差网络。该和差网络工作在Ka频段,内部集成了无源和差器、功分器、有源收发组件、开关矩阵、控制电路等多个功能单元,采用小型化、高集成设计方法,大大减少了整个系统的质量和体积。实验结果表明,在中心频点3 GHz带宽内,该和差网络实现了良好的端口匹配,小型化的设计没有影响射频性能。     

基于光纤通讯自适应数字波束形成的应用

自适应数字波束形成是新一代相控阵雷达的核心技术,该文讨论了ADBF的工程实现算法,并给出了一种基于光纤通讯、FPGA和DSP平台数字多波束形成系统模块,该DBF模块具有高速数字波束形成、通道校正、自适应干扰置零功能,通道和波束数可扩展功能.此模块已在某三坐标雷达和无源雷达中获得成功应用.     

5 mm高隔离鳍线单刀双掷开关

设计并实现了5 mm(U频段)单刀双掷(Single Pole Double Throw,SPDT)开关模块.该开关模块采用鳍线并联PIN二极管电路结构形式,通过采用一种全新的高隔离度措施,获得高隔离、低插损开关特性.经加工测试,开关模块在50～56 GHz频带内隔离度大于50 dB,插损小于2.3 dB.该模块已应用于5 mm射频组件中.     

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.