高带外抑制特性微波陶瓷波导滤波器的设计

介绍了陶瓷波导滤波器的设计理论,采用耦合通槽分别与浅、深耦合盲孔的组合结构来满足正、负耦合带宽要求,通过调整3~6腔体的交叉耦合来改善滤波器传输曲线的对称性,同时实现滤波器近端和远端的带外抑制,在此基础上设计了一款5G基站用六腔陶瓷波导滤波器。在该滤波器的优化过程中,详细讨论了3~6腔体交叉耦合通槽的相对位置偏移量和交叉耦合通槽的长度对滤波器传输零点位置、近端和远端带外抑制特性的影响,并给出了相关的变化规律。经优化后滤波器性能指标如下:中心频率为3.5 GHz,工作带宽为200 MHz,插入损耗≤1.2 dB,回波损耗≥17 dB,近端带外抑制≥25 dB,远端带外抑制≥51 dB。根据仿真模型结构参数制备得到的样品,其性能测试结果与仿真结果吻合良好。     

一种高可靠连体式介质滤波器设计

根据椭圆函数响应,采用相对介电常数为37的高品质因数微波介质材料,该文设计了一种低损耗、连体式四级介质滤波器。通过1-4谐振器之间使用级联四元组(CQ)电容加载耦合,经优化后滤波器中心频率为1 268 MHz,工作带宽为25 MHz,插入损耗≤2.5 dB,回波损耗≥18 dB,近端带外抑制≥40 dB。根据仿真模型结构参数,优化成型和金属化工艺,制备得到的样品,通过可靠性环境试验表明,该滤波器的性能测试结果与仿真结果吻合良好。     

改进型3IDT-LCR结构的低损耗小矩形系数SAW滤波器

通过理论仿真,该文研制了一种改进型的3IDT-LCR结构,并基于该结构在42°Y-X LiTaO₃压电基片上研制出一种低损耗、小矩形系数的SAW滤波器。滤波器标称频率为253.75 MHz,实测插入损耗1.05 dB,低端带外抑制接近80 dB,高端带外抑制接近65 dB,-1 dB带宽10.52 MHz,-3 dB带宽12.54 MHz,-40 dB带宽16.68 MHz,矩形系数1.33。实测结果表明,该改进型3IDT-LCR结构的SAW滤波器具备低插入损耗、小矩形系数和高带外抑制的特点。     

一种高性能腔体带通滤波器的研究与设计

为了抑制CDMA800网络下行频段的噪声,利用HFSS和二维电路仿真软件AWR的协同仿真,设计了同轴腔体滤波器,该滤波器利用交叉耦合结构实现了边带外的高抑制性能。所设计滤波器中心频率为875MHz,带宽10MHz;插入损耗〈-0．25dB;回波损耗〉-20dB;带外抑制〉-80dB,满足了设计要求。仿真结果表明：该滤波器结构设计尺寸小、频带宽、带外抑制高、带内插损小等,在通信领域具有良好的应用前景。     

薄膜体声波滤波器结构和设计

随着无线通信设备的小型化发展,薄膜体声波谐振器(FBAR)已成为国内外研究热点.该文综述了FBAR滤波器的拓扑结构、工作原理和仿真模型,并选择梯形滤波器方案,通过ADS射频仿真软件建立起MBVD一维等效电路模型模拟其传输特性.按照全球定位系统(GPS)滤波器设计要求,设计了频带为1 530～1 590 MHz的窄带滤波器.仿真表明,增加串、并联谐振器阶数可有效提高带外抑制,而减少其面积比在进一步增加带外抑制的同时,减少了插损和器件整体面积.设计所得滤波器带宽60 MHz,带外抑制50 dB,插损3 dB.     

多传输零点LTCC带通滤波器的设计与实现

提出了一种阻带具有多个传输零点的带通滤波器设计方法,基于低温共烧陶瓷(LTCC)技术实现,可满足移动通信用滤波器小型化、高性能的要求。在电路设计中,通过改进滤波器谐振器结构,分别在阻带的低端近端、高端远端引入传输零点以提高带外抑制。借助三维仿真软件,进行指标、结构的仿真优化,设计并制作了一款尺寸为6 mm×3 mm×2 mm的LTCC滤波器,其中心频率f0=2.25 GHz,0.5 dB带宽不小于100 MHz,通带内损耗不大于1.8 dB,在1.33,1.78 GHz和二次谐波处均有传输零点。实测结果表明,该滤波器在阻带低端和二次谐波处有较好的抑制,因此其在移动通信系统中会有广泛应用。     

有源镜像抑制复数滤波器设计

采用SMIC 0.18μm CMOS工艺设计实现了一款3阶有源RC复数滤波器.该滤波器适用于无线传感网射频接收机.滤波器中心频率为3MHz,带宽为250kHz/500kHz/1MHz/2MHz可配置,仿真结果显示,滤波器通带增益约为10dB,镜像抑制大于35dB,噪声系数小于45dB,三阶交调点(IIP3)优于28.5dBm,消耗电流为0.9mA.经仿真验证,该设计各项性能均满足无线传感网射频接收机要求.     

一种基于LTCC技术的UHF波段高性能带通滤波器

介绍了一种基于低温共烧陶瓷(LTCC)技术实现的UHF波段高性能带通滤波器,其中心频率为490MHz。由于该滤波器频率较低、波长较长,为了减小滤波器的尺寸,本设计采用了半集总半分布结构来实现。通过增加传输零点和滤波器级联技术大大提高了滤波器的带外抑制度。借助三维仿真软件进行优化仿真,设计出了一个中心频率为490MHz、带宽为100MHz、带外抑制优于40dB、尺寸仅为6.4mm×4.0mm×1.5mm的带通滤波器。实测结果与电磁仿真结果较为吻合。     

2140MHz双模介质谐振滤波器的结构设计和仿

研究对于CDMA频段2 140 MHz的微波双模介质滤波器的设计原理和计算方法,同时使用高频结构仿真软件对所设计的滤波器进行了仿真分析.根据以往的双模结构,使用了利用切角进行双模耦合的新结构.所要求的滤波器的参数指标为:中心频率f0=2 140 MHz ,插入损耗IL<0.1 dB,带宽BW=10 MHz ,带内波动Ap<0.05 dB,100 MHz处带外抑制As>25 dB.仿真结果表明该结构可以更加有效地减小插入损耗,且体积比传统滤波器减小了很多,有利于器件小型化.     

LTCC抗EMI滤波器研制

采用低温共烧陶瓷(low temperature co-fired ceramics,LTCC)集成技术研制出小型的抗电磁干扰(EMI)滤波器,同时通过在滤波器带外引进一传输零点,增加了滤波器的带外陡度。结果表明:该滤波器的截止频率为84 MHz(3dB),带外抑制≥30 dB(250~2 500 MHz),达到设计要求。其外形尺寸为2.00 mm×1.25 mm×0.80 mm,远小于传统的同类型滤波器。     

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.