X波段低噪声放大器的设计

为了实现X波段的低噪声放大器,介绍了按最小噪声系数设计,采用两级级联,利用Eudyna公司的HEMT晶体管设计制作的低噪声放大器。通过专用微波电路设计软件(AWR),对该电路的稳定系数、功率增益、噪声系数、驻波比、匹配网络等进行了仿真分析。根据分析结果制作的X波段LNA取得了如下指标:在9.5～10.5 GHz频带内,功率增益大于22 dB,噪声系数小于1.5 dB,输入输出驻波小于1.7。     

一种噪声系数为1.4 dB的S波段MMIC低噪声放大器

报道了一种可直接应用于无线接收系统前端的具有较低噪声系数和较高相关增益的MMIC低噪声放大器,该低噪声放大器采用0.50 μm GaAs PHEMT工艺技术制作.电路设计采用两级级联结构,为减小电路面积采用集总参数元件匹配电路,并用ADS软件仿真无源元件寄生效应.电路测试结果表明:在2.8～3.5 GHz 频段内噪声系数低于1.4 dB,同时相关增益大于25 dB,增益平坦度小于0.5 dB,输入输出反射损耗小于-10 dB.     

S波段低噪声放大器的ADS仿真与设计

介绍低噪声放大器设计的理论基础,并重点介绍了低噪声放大器的主要性能指标:噪声系数、功率增益、驻波比、稳定性等。以ATF38143晶体管为例介绍了ADS仿真软件设计低噪声放大器的方法和主要步骤。采用三级级联结构设计出满足指标的S波段低噪声放大器链路。该放大器链路的指标为噪声系数小于1.2,功率增益大于50dB,增益平坦度小于0.5dB,VSWR小于1.8的低噪声放大器,带宽为6MHz,并具有一定的带外抑制能力。     

S波段平衡式限幅MMIC低噪声放大器设计

结合混合微波集成电路(HMIC)工艺和砷化镓单片微波集成电路(MMIC)工艺各自优势,设计制作了一款小型化大功率S波段平衡式限幅MMIC低噪声放大器.采用平衡式结构,提高了限幅功率容量和可靠性.由于金丝键合线的等效电感具有更高Q值,低噪声放大器单片的输入匹配采用外部金丝键合线匹配,有效降低了低噪声放大器单片的噪声系数.限幅器采用混合集成工艺制成,能够耐受较大功率.利用微波仿真软件,设计制作了兰格(Lange)电桥、限幅电路和低噪声放大器输入匹配等电路.最终产品尺寸仅为22 mm×16 mm×6 mm,在2.7～3.5 GHz内增益27 ～ 28 dB,噪声系数小于1.3 dB,驻波比小于1.3,该平衡限幅MMIC低噪声放大器可承受功率超过200 W、占空比为15％的脉冲功率冲击.     

基于ADS仿真的宽带低噪声放大器设计

设计了一个S频段宽带低噪声放大器.该放大器采用两级E-PHEMT晶体管(ATF541M4)级联结构,单电源供电模式.应用微波仿真软件ADS对匹配电路进行了优化设计,最后通过S参数及谐波平衡仿真得到放大器的各项性能参数,在2.7～3.1 GHz频率范围内噪声系数小于0.6 dB,带内增益大于30 dB,带内平坦度小于±1 dB,输入输出驻波比小于1.6 dB,1 dB增益压缩点输入功率不小于-15 dBm.仿真结果表明,该设计完全满足性能指标要求.     

一种采用新型复合沟道GaN HEMTs低噪声分布式放大器

设计研制了一种新型的低噪声分布式放大器,采用了栅长为1μm的低噪声复合沟道Al0.3Ga0.7N/Al0.05Ga0.95N/GaN HEMT (CC-HEMT). 给出了低噪声分布式放大器的仿真和测试结果. 测试结果显示低噪声分布式放大器在2~10GHz频率范围内,输入和输出端口驻波比均小于2.0,相关增益大于7.0dB,带内增益波纹小于1dB . 在2~6GHz频率范围内,噪声系数小于5dB;在2~10GHz频率范围内,噪声系数小于6.5dB; 测试结果与仿真结果较吻合.     

一种采用新型复合沟道GaN HEMTs低噪声分布式放大器

设计研制了一种新型的低噪声分布式放大器,采用了栅长为1μm的低噪声复合沟道Al0.3Ga0.7N/Al0.05Ga0.95N/GaN HEMT(CC-HEMT).给出了低噪声分布式放大器的仿真和测试结果.测试结果显示低噪声分布式放大器在2～10GHz频率范围内,输入和输出端口驻波比均小于2.0,相关增益大于7.0dB.带内增益波纹小于1d8.在2～6GHz频率范围内,噪声系数小于5dB;在2～10GHz频率范围内,噪声系数小于6.5dB;测试结果与仿真结果较吻合.     

Ka波段单片低噪声放大器

利用0.25 μm GaAs PHEMT工艺设计并制作了一种Ka波段低噪声放大器芯片.提出了适用于低噪声放大器的PHEMT器件特征.电路采用四级级联结构.利用微带电路实现输入、输出和级间匹配.通过对电路增益、噪声系数和驻波比等指标进行多目标优化,确定了器件参数.该放大器测试结果为:26.5～36 GHz频段内增益大于20 dB;多数测试点噪声系数小于3 dB,其中34 GHz频点噪声仅为1.94 dB;芯片面积2.88 mm×1 mm.     

S波段平衡式限幅放大器设计

采用混合集成电路工艺,设计了一款小尺寸限幅低噪声放大器(LNA)。优化了限幅电路设计,明显缩小了电路体积。低噪声放大器采用负反馈结构,以改善增益平坦度。采用平衡式结构,提高限幅器的功率容量和放大器的1 dB压缩点输出功率(P-1 dB)。设计制作了Lange电桥,作为平衡式限幅放大器的输出电桥。该放大器工作电压5 V,电流151 mA,测试结果显示,在频带2.7~3.0 GHz内,噪声系数小于1.5 dB,小信号功率增益大于36 dB,增益平坦度小于0.6 dB,输入输出驻波比小于1.3,P-1 dB大于13 dBm。该限幅放大器能够承受脉冲功率300 W、脉宽300μs和占空比为30%的信号,外形尺寸为27 mm×18 mm×5 mm。     

0.18μm CMOS 3.1-10.6GHz超宽带低噪声放大器设计

介绍了一种基于0.18μm CMOS工艺、适用于超宽带无线通信系统接收前端的低噪声放大器.在3.1～10.6GHz的频带范围内对它仿真获得如下结果:最高增益12dB;增益波动小于2dB;输入端口反射系数S11小于-10dB;输出端口反射系数S22小于-15dB;噪声系数NF小于4.6dB.采用1.5V电源供电,功耗为10.5mW.与近期公开发表的超宽带低噪声放大器仿真结果相比较,本电路结构具有工作带宽大、功耗低、输入匹配电路简单的优点.     

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.     

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.     

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.     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.