热处理对红外窗口镀层金属的影响

采用直流磁控溅射法制备红外透过窗口Ge窗的镀层金属。分别讨论了热处理温度和热处理时间对Ge窗金属化体系力学特性的影响。用纳米压痕仪测试仪测试Ge窗金属化体系的显微力学特性,并用金相显微镜观测金属薄膜的表面形貌,发现退火温度对Ge窗片上的金属薄膜的力学特性有较明显影响。     

低价、高效、微波产品用的TPA覆铜版

随着信息产业的飞速发展,高频信号设备,如高速计算机、移动电话、卫星通信等,都已从兆赫频段扩展到千兆赫,这就意味着对它们所用的微波电路基板提出了更高的要求.长期以来,高频微波基板几乎没有越出使用聚四氟乙烯的老传统,但是,它有若干缺点玻璃化温度低,故刚性差;加工复杂,故成本高;金属化孔镀层与孔壁的结合力弱,故可靠性不高. 多年来,美国GIL科技公司一直在研制替代聚四氟乙烯的材料,经过姐妹公司的合作,终于研制成功了TPA板材,这种材料克服了上述缺点,从而获得了美国专利.本文介绍了TPA层压板的电气特性、机械特性和热效应,给出了许多宝贵数据.     

低价、高效、微波产品用的TPA覆铜板

随着信息产业的飞速发展,高频信号设备,如高速计算机、移动电话、卫星通信等,都已从兆赫频段扩展到千兆赫,这就意味着对它们所用的微波电路基板提出了更高的要求。长期以来,高频微波基板几乎没有越出使用聚四氟乙烯的老传统,但是,它有若干缺点:玻璃化温度低,敌刚性差;加工复杂,故成本高;金属化孔镀层与孔壁的结合力弱,故可靠性不高。 多年来,美国GIL科技公司一直在研制替代聚四氟乙烯的材料,经过姐妹公司的合作,终于研制成功了TPA板材,这种材料克服了上述缺点,从而获得了美国专利。本文介绍了TPA层压板的电气特性、机械特性和热效应,给出了许多宝贵数据。     

人工制备生物消光材料空气动力学特性

人工制备的几种生物材料生产成本低、密度小、形态可控、安全环保,在可见光和红外等波段具有较好的消光能力,可作为一种新型消光材料,弥补无机消光材料的不足。针对当前军、民用领域对新型生物消光材料的需求,将生物消光材料中的絮状生物颗粒等效为子弹玫瑰花型粒子,根据牛顿第二定律和梯度-输运理论,建立生物消光材料沉降模型和扩散模型,并讨论絮状生物颗粒结构和风速、大气稳定度对生物消光材料空气动力学特性的影响。结果表明:分枝数目、长度、半径决定絮状生物颗粒结构;在某种特定条件下,絮状生物颗粒沉降速度较等体积球颗粒沉降速度降低了50％;烟团遮蔽面积可达20 m2以上。模型的构建将为生物消光材料发展及实际应用提供理论基础。     

PCB孔金属化电阻的测量与分析

一、测量方法与原理 测量印制电路板孔金属化镀层的电阻值,并根据此电阻值和印制电路板的基材厚度、金属化孔的直径来计算孔金属化镀层的平均厚度,是检查印制电路板金属化孔镀层     

低价、高效、微波产品用的TPA覆铜板

随着信息产业的飞速发展，高频信号设备，如高速计算机、移动电话、卫星通信等，都已从兆赫频段扩展到千兆赫，这就意味着对它们所用的微波电路基板提出了更高的要求。长期以来，高频微波基板几乎没有越出使用聚四氟乙烯的老传统，但是，它有若干缺点：1）玻璃化温度低，因而刚性差；2）加工复杂，因而成本高；3）金属化孔镀层与孔壁的结合力弱，因而可靠性不高。多年来，美国GIL科技公司一直在研制替代聚四氟乙烯的材料，经过姐妹公司的合作，终于研制成功了TPA板材，这种材料克服了上述缺点，从而获得了美国专利。本介绍了TPA层压板的电气特性、机械特性和热效应，给出了许多宝贵数据。     

雷达用多层微波综合背板制造工艺研究

对多种型号雷达用多层微波综合背板材料CLTE-XT进行了性能及特点介绍。创新性运用埋置膜电阻技术、金属化孔制造的反钻孔技术,实现了多层微波综合背板的制造。并对其制造过程中所涉及的层间定位、多层化制造、孔金属化实现等关键技术进行了详细阐述,对此类微波多层背板的制造具有指导意义。     

微波印制电路板制造工艺及其电阻集成

介绍了微波印制电路板制造工艺中的钻孔、孔金属化和图形制作等主要步骤以及电阻集成的方法。通过在微波印制电路板基材表面涂覆低介电常数的材料,改变了基材表面形貌和特性,采用薄膜工艺在微波印制电路板上集成了30～50Ω/的NiCr电阻。最后简要介绍了微波多层印制电路新技术。     

化学镀Ni-Zn-P FBG及其温度传感特性

通过化学镀和电镀的方法使光纤布拉格光栅金属化,可对光纤光栅进行保护、增敏,使其具有可焊性,进而可通过焊接嵌入金属或封装在表面监测工作状态。采用化学镀Ni-Zn-P方法对光纤布拉格光栅进行了金属化,通过体视显微镜和金相显微镜观察Ni-Zn-P镀层;对化学镀后的光纤光栅进行了30~70℃温度传感试验,分析了传感特性。结果表明:化学镀后的光纤与镀层结合良好,具有导电性可以进一步电镀;化学镀光栅与裸光栅相比温度传感灵敏度提升1.1倍,存在迟滞误差,随静置时间的推移灵敏度不变,迟滞误差减小。残余应力是产生迟滞误差的主要原因,分析讨论了残余应力的来源和残余应力对金属化光栅中心波长的影响。     

电磁防护材料专题

题目：Fe3O4／Ni复合纳米颗粒的制备及其微波吸收特性 作者：哈日巴拉、付乌有、杨海滨、刘冰冰、邹广田 摘要：采用电爆炸技术,合成了粒径约为70nm的Ni纳米颗粒,以3-巯基丙基三甲氧基硅烷偶联剂（MPTS）对Ni颗粒进行表面改性,利用共沉淀法对改性Ni颗粒进行包覆得到核-壳结构的复合纳米颗粒。     

金属栅网的远红外光学特性

介绍了金属栅网在远红外波段的应用，并根据微波传输线理论推导了栅网的透射率、反射率、吸收率公式和相位表达式，提出用等效三角形描述不同结构的栅网，并与等效电路法的结果作了对比和讨论。     

电介质/金属型红外空芯波导的传输特性和结构设计

由普通空芯波导的模式结构和传输性质出发，讨论了电介质/金属型空芯波导的传输特性，分析了HE11模在红外波段的低损耗传输条件。并在此基础上设计了电介质/金属型空芯波导的最佳结构，对膜系的选择也提供了明确的指导。     

Loop plasma and metallic antennas for mobile entities

Amethod of estimating the specific conductivity and dielectric relative dielectric permittivity of plasma antennas with mercury admixture has been proposed and investigated in two different microwave ranges. Based on the obtained data of specific conductivity and relative dielectric permittivity the radiotechnical parameters (VSWR and the efficiency) were computed via simulation and calculation of antennas in the FEKO software environment using the integral equation method and the method of moments with or without due regard for the impact of mercury admixture. For comparison plasma and metallic antennas the characteristics of similar metallic antennas were also considered. A significant difference of the above characteristics was noted. The comparison of the calculation results of VSWR of plasma antennas with experimental data revealed their acceptable agreement. This is the evidence of an adequate approach to specifying the initial data in terms of the plasma parameters and the correct computer simulation of plasma antennas in the microwave range. The radiotechnical characteristics of an L-shaped loop plasma antenna bent for the purpose of reducing the aerodynamic resistance in case of mounting antenna at mobile entities were also investigated. It is recommended to reduce the amount of mercury introduced into plasma antennas for improving the ecological situation. The method proposed can be used for taking into account the impact of other admixtures introduced into plasma antennas.     

Visible/Infrared/Microwave Agriculture Classification, Biomass, and Plant Height Algorithms

This paper describes the results of a study to determine if visible, infrared, and microwave data is correlated to crop-canopy characteristics (biomass and crop height) and can improve estimates of crop acreage. The objectives were to 1) determine if different crops can be discriminated using multifrequency microwave data, and 2) determine which visible, infrared, and microwave spectral regions can classify crops and correlate well to plant biomass, crop height, and the perpendicular vegetation index (PVI). The study was conducted at Dalhart, Texas, in 1980. Aircraft multispectral data collected during the study included visible and infrared data and active multifrequency microwave data. Ground-truth data from each field consisted of soil moisture, total plant biomass, and crop height. Results indicated that C- (4.75 GHz), L- (1.6 GHz), and P- (0.4 GHz) band active microwave data combined with visible and infrared data maintained or improved crop-discrimination accuracy compared to models using only visible and infrared data. The active microwave frequencies were more sensitive to plant height differences than total biomass differences; the K- (13.3 GHz) and C-bands were sensitive to height variations in short plants, while the P-band was sensitive to differences between tall and short plants.     

Effect of annealing temperature on structural,electrical and optical properties of spray pyrolytic nanocrystalline CdO thin films

Nanocrystalline CdO thin films were prepared onto a glass substrate at substrate temperature of 300 °C by a spray pyrolysis technique. Grown films were annealed at 250, 350, 450 and 550 °C for 2.5 h and studied by the X-ray diffraction, Hall voltage measurement, UV-spectroscopy, and scanning electron microscope. The X-ray diffraction study confirms the cubic structure of as-deposited and annealed films. The grain size increases whereas the dislocation density decreases with increasing annealing temperature. The Hall measurement confirms that CdO is an n-type semiconductor. The carrier density and mobility increase with increasing annealing temperature up to 450 °C. The temperature dependent dc resistivity of as-deposited film shows metallic behavior from room temperature to 370 K after which it is semiconducting in nature. The metallic behavior completely washed out by annealing the samples at different temperatures. Optical transmittance and band gap energy of the films are found to decrease with increasing annealing temperature and the highest transmittance is found in near infrared region. The refractive index and optical conductivity of the CdO thin films enhanced by annealing. Scanning electron microscopy confirms formation of nano-structured CdO thin films with clear grain boundary.     

用于空间领域的太赫兹技术研究概况

作为电磁波中从红外光到微波的过渡区,太赫兹波所具有的独特性能已得到了人们的广泛认识。随着太赫兹辐射源、太赫兹探测器等单元技术研究的不断成熟,美国、欧洲和日本已率先将其应用于空间天文观测、深空探测和对地气象环境监测等领域。重点总结了这些应用中的技术发展情况,并简要分析了太赫兹雷达与通信技术的研究状况和应用前景。     

Wireless infrared communications

The use of infrared radiation as a medium for high-speed short-range wireless digital communication is discussed. Available infrared links and local-area networks are described. Advantages and drawbacks of the infrared medium are compared to those of radio and microwave media. The physical characteristics of infrared channels using intensity modulation with direct detection (IM/DD) are presented including path losses and multipath responses. Natural and artificial ambient infrared noise sources are characterized. Strategies for designs of transmitter and receivers that maximize link signal-to-noise ratio (SNR) are described. Several modification formats are discussed in detail, including on-off keying (OOK) pulse-position modulation (PPM), and subcarrier modulation. The performance of these techniques in the presence of multipath distortion is quantified. Techniques for multiplexing the transmissions of different users are reviewed. The performance of an experimental 50-Mb/s on-off-keyed diffuse infrared link is described     

Isothermal DC and microwave characterizations of power RF siliconLDMOSFETs

Presented in this paper are two new approaches for the acquisition of both isothermal DC current-voltage (I-V) characteristics and microwave S-parameters of power RF LDMOSFETs. In the first approach, a 3D tensor product B-spline representation is used to extract isothermal DC I-V characteristics from DC I-V characteristics measured at various substrate temperatures. The average device surface temperature is measured using an infrared sensor. A single effective thermal resistance is found to map the entire electrothermal profile of the device, justifying the isothermal DC I-V definition used. In the second approach, isothermal I-V and microwave data are directly measured with an efficient procedure that keeps the average device surface temperature constant. Excellent agreement is obtained between the numerical extraction and the direct measurement approach. Finally, the comparison of the transconductance extracted from the isothermal DC I-V and microwave data confirms the presence of a small low-frequency dispersion in LDMOSFETs not due to self-heating     

红外探测器工艺用器皿清洗方法研究

红外探测器材料一般为窄带系材料,在其制备工艺过程中,杂质离子更容易导致缺陷能级或表面快态复合中心,需选取较优的器皿清洗方法,对工艺用器皿所含金属离子进行评测控制。本文通过电感耦合等离子体质谱仪对比碲镉汞红外探测器工艺线上不同的器皿及清洗方法,对清洗后金属离子残留测试分析,获得较佳的器皿清洗方法,更好地保证红外探测器制备后性能。     

盒体热压成型工艺及模具设计

概述了超塑热压成型技术及其特点,针对微波铝盒体类零件的特点,讨论了影响盒体超塑热压的几个关键因素,介绍了成型零件和模具设计要点,详细分析了压力、温度和速率等工艺参数的确定及选用原则,提出对不经过预处理的供应态毛坯进行直接压制成型的超塑性等温挤压成型工艺及控制要点,提高了生产效率,实现了超塑性等温热挤压成型工艺在复杂微波...