有源相控阵雷达天线测试的时序实现与优化

天线测试是有源相控阵雷达设计中重要组成部分。相较于无源天线测试闭环的相参信号使用方式,有源相控阵雷达天线采用开环的测试过程,对于信号间的时序关系要求更加严格。对测试所用的时序关系进行分析并对其进行优化,实现了一种有效的测试方法。使用优化前后的两种方法对同一型号雷达进行实测,测试结果基本一致,但优化方法测试时间仅为原方法的11.3%。     

有源相控阵天线近场测试方法研究

天线测试是有源相控阵雷达设计中的重要组成部分,介绍了平面近场测试系统的搭建和测试方法,以及利用平面近场测试系统的口面场进行反演,从而快速测试出有源相控阵雷达天线波瓣的相关性能,实测某Ku天线副瓣电平低于-25d B,扫描指向精度,增益等指标满足设计指标要求。为完成宽带有源相控阵天线的性能测试提供了有效的方法。     

有源阵列天线的系统噪声

有源阵列天线系统的噪声是有源相控阵雷达、通讯等系统噪声的主要成分,本文从微波网络理论入手,结合统计理论对有源阵列天线的噪声温度进行理论分析,为有源阵列天线系统噪声的分析、设计和测试提供了完整的数学模型和方法.     

毫米波相控阵板级集成天线技术研究

随着毫米波雷达及通信系统的快速发展,有源相控阵天线日益成为当前研究的热门天线形式。然而,毫米波有源相控阵存在空间紧凑、结构复杂、装配繁琐等问题。本文介绍了一种可应用于毫米波相控阵的板级集成天线,并对其天线阵列、垂直过渡等关键结构的设计进行了讨论。该阵面将天线阵列、收发组件和馈电网络全部集成在一块基板上,具有结构简单易于量产的特点。文末给出了对所设计的有源阵面的暗室测试结果,结果表明该天线在毫米波雷达和通信系统中具有巨大的应用潜力。     

有源相控阵天线发射方向图测试简易方法

有源相控阵天线需要对接收和发射两种状态的天线方向图进行测试。现有天线测试远场只能进行接收态的方向图测试,介绍了在远场进行发射态方向图测试的一种简易方法。利用远场的测试转台和发射喇叭,使用频谱分析仪接收有源相控阵天线发射的数据,编制测试软件采集处理数据,即能实现有源相控阵天线发射方向图的测试。该测试方法简单易行。     

一种舰载有源相控阵雷达天线舱腐蚀控制防护工艺研究

针对海用环境下一种舰载有源相控阵雷达天线舱的腐蚀控制防护设计展开论述,从改善天线舱工作环境、天线舱框架主要材料选择、密封设计、涂覆体系等方面进行控制防护,满足舰载有源相控阵雷达腐蚀控制防护设计的总体需求。     

基于有源相控阵雷达的通信系统

目前,飞机上装载的通信电台,其数据率在需要传输大容量的数据时无法满足要求.用有源相控阵雷达来接收通信信号,不仅利用了有源相控阵雷达天线高增益的特点,而且不用另外增加天线,减少了成本.针对这样一些优点,提出了一个基于有源相控阵雷达的通信方案.通信系统以一般的有源相控阵雷达系统为基础,从理论上分析了通信系统的构成及通信过程,并解决了雷达接收机没有同步电路所带来的问题.     

相控阵天线方向图远场测试方法研究

天线方向图是描述天线性能的重要参数,对于有源相控阵天线而言,其方向图的测试通常是一项复杂而又艰巨的工作.为适应多频点、多通道有源相控阵雷达天线测试的需要,文中提出了一种基于频率高速捷变、多通道并行处理的远场测试方法.该方法能够有效地降低测量时间,提高远场测试的效率.     

有源相控阵天线自动测试系统设计

针对现代有源相控阵雷达天线T/R组件测试通路多、测试数据处理量大、测试效率低的特点,设计了一种适用于大规模T/R组件测试的有源相控阵天线自动测试系统。该系统设计通过GPIB接口或以太网对VNA(矢量网络分析仪)进行访问控制与数据采集,充分利用了现代计算机强大的数据处理与分析能力,不仅解决了有源相控阵天线故障诊断与自动校正问题,而且还极大地提高了工作效率,节约了人力成本。实际应用表明:该测试系统工作稳定,使用方便,能够充分满足T/R组件测试需要。     

有源相控阵雷达天线实时校正方法

针对有源相控阵天线的超低副瓣、高增益及精确波束指向等性能的实现进行分析研究。首先分析一般相控阵雷达天线及其校正耦合网络的结构,并对实时校正的原理以接收校正为例进行详细的阐述,最后通过某有源相控阵雷达天线实测数据验证该方法的有效性及可行性。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.