新型超宽带单极子天线的设计

研制了一款超宽带印刷单极子天线,通过在接地板上开方形槽,展宽带宽的同时也改善了带内特性.再在金属贴片顶部开扇形槽,进一步在高频段展宽了频带.实测结果显示,改进后的天线- 10 dB阻抗带宽为2.1 ～25.5 GHz,而原不加槽天线的仿真带宽为2～11.4 GHz,带宽展宽了14 GHz.仿真和实测结果显示,天线在2....     

一种新型双环宽带圆极化微带天线设计

针对微带天线存在固有频段窄、辐射效率低,且难以获得高增益的问题,设计制作了一种新型双环宽带圆极化微带天线。天线贴片单元采用由槽型环和带状环组成的槽带状结构。槽型环和带状环分别在频率较低部分和频率较高部分各提供一个最小轴比值,通过两个最小轴比值的适当结合达到明显的带宽增强效果。天线利用宽带巴伦结构进行馈电,有效增强了阻抗匹配。通过参数优化和实物制作,仿真与实测结果表明,该天线的阻抗带宽(VSWR≤2)和3 dB轴比带宽分别达到了37%和29.8%,增益达到6.4 dB。     

超高频RFID小型化读写器天线设计

提出了一款应用于超高频段(Ultra High Frequency,UHF)(912 ~935 MHz)的射频识别(RFID)读写器圆极化单层结构微带天线,基板采用FR4 板材达到价格低廉、辐射贴片采用开槽的结构实现小型化、接地板采用开槽结构提高天线的增益,该天线实现了小型化设计,满足了天线的设计要求。利用三维电磁仿真软件对天线模型进行了分析,仿真与测试结果吻合良好。天线测试结果表明:回波损耗小于-10 dB 的阻抗带宽为25 Hz(910 ~ 935 MHz),轴比(AR)小于3 dB的带宽为21 MHz(914 ~935 MHz);在UHF 频段内,读写器天线的最大增益为-1.2 dB,所以本天线能满足我国射频识别读写器的应用要求,具有良好的应用前景。     

利用短路片结构的小型超宽带单极天线

介绍了一种利用短路片结构的小型超宽带(UWB)平面单极天线,采用椭圆型金属片作为辐射单元,用同轴线进行馈电.通过将辐射单元和接地板用短路片相连,降低了阻抗带宽低频端的频率,扩展了带宽,并缩小了天线的尺寸.仿真和实测结果表明,该天线的阻抗带宽覆盖了3.1～10.6GHz的民用超宽带频段.     

梯形接地板结构超宽带天线设计

在圆形单极天线的基础上进行改进设计了一款梯形接地板结构的超宽带单极天线。根据接地板电流的分布强弱,削去矩形接地板两端对电流影响较小的三角形形状部分,构成梯形接地板。经过仿真优化实验结果表明,该天线电压驻波比VSWR2的阻抗带宽为3.1~17 GHz,工作频段内具有全向辐射特性,且天线只有20 mm×22 mm×1.6 mm,结构简单,适合超宽带无线通信系统的要求。     

一种新型Ka频段圆极化微带天线设计

提出了一种Ka频段圆极化微带天线的新设计,采用缝隙耦合馈电方式,通过在接地板开L型缝隙实现天线的圆极化工作。对天线阵列进行了仿真优化和加工实测,仿真和测试结果表明了设计的可行性。天线仿真和实测的相对阻抗带宽分别为3.9%和4.2%,仿真和实测的轴比相对带宽分别为2%和3.5%。天线具有良好的圆极化特性,可应用在卫星通信中。     

Ka频段宽带圆极化微带天线

面向Ka频段高通量卫星对天线的需求,设计了一种Ka频段宽带圆极化微带天线. 天线单元主要由圆形辐射贴片和缝隙耦合馈电结构组成,通过两个类T形缝隙结合实现宽带圆极化. 天线仅有三层金属层,结构简单. 仿真结果显示,天线单元的相对阻抗带宽为31.5%（25.1～34.5 GHz）,相对3 dB轴比带宽为20.3%（26.5～32.5 GHz）. 由于单元尺寸较小,不便于对其性能进行验证,因此利用该天线单元组成2×2天线阵列,并进行加工测试. 仿真与试验结果表明,天线阵列阻抗带宽以及3 dB轴比带宽可以覆盖25.6～33.1 GHz频率范围,实测结果与仿真结果一致性良好.     

一种应用于LTE和5G中频段的宽带双极化基站天线

设计了一款适用于LTE和5G中频段的宽带双极化微基站天线.该天线主要由四部分组成:主辐射器,馈电巴伦结构,反射面和方形寄生贴片.其中辐射面上的圆形连接条产生多个电流路径,并引入额外的谐振点实现了阻抗匹配,同时方形寄生贴片有效扩展了高频段的带宽.实测结果表明,该天线具有50％(2.2～3.65 GHz)的阻抗带宽,反射系...     

一种适用于WLAN 的新型小型化双极化天线

设计了一种可工作于WLAN 2.4GHz频段的小型化双极化天线.该天线采用双层对称结构介质板,把辐射贴片四边分别切割成凸字形形状,实现了天线小型化和有效展宽天线带宽.同时在接地板开4个对称的十字形缝隙,进一步拓宽天线带宽和明显减小天线的整体尺寸并提高了天线辐射性能.由此设计制作的天线实验结果为:小于-10dB回波损耗的频段为2.37 ～ 2.59GHz,相对阻抗带宽达9.1％,端口隔离度达到了33dB,增益最大值约3.63 dBi,表明该微带天线具有宽频带和良好的辐射性能.此外,该天线结构简单紧凑,易于加工制作和集成,适合应用于移动终端.     

小型化超宽带平面单极天线的设计与分析

针对超宽带系统对天线小型化及宽带化的要求,基于平面单极天线模型,采用辐射单元开圆形槽及缺陷接地板结构,提出了一种反L形接地板结构的超宽带平面天线。仿真分析表明,该天线谐振特性良好,阻抗带宽达到了12 GHz,同时天线体积仅为20 mm×20 mm×1.6 mm,实现了小型化,且结构简单,易于加工及集成,适合未来无线通信发展的需求。     

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.