一种LTCC滤波器的快速设计与实现

低温共烧陶瓷(LTCC)技术可以实现微波器件的小体积和高可靠性。基于集总参数形式滤波器的设计思路,利用LTCC技术的多层结构和立体布线技术,通过Ansoft HFSS软件对滤波器中电容和电感元件的特性参数提取,可以快速地完成滤波器中电容和电感元件的建模与仿真,从而实现LTCC滤波器的快速设计。利用这种快速设计方法,设计并实现一款截止频率为1.5 GHz的低通滤波器,测试结果与仿真结果相吻合。该结构滤波器的尺寸显著减小,从而有利于实现电路的小型化。     

超小型的片式LTCC滤波器设计

针对微波设备小型化需求,利用低温共烧陶瓷(LTCC)技术,建立了小型化的LTCC电感和LTCC电容模型,并设计了内埋置LTCC电感和电容的片式L频段集总型带通滤波器,同时为了满足高频应用,设计了X频段分布带状线LTCC带通滤波器,通过用电磁场仿真软件ANSYS HFSS对滤波器进行建模及三维仿真优化,加工实现,制成的L和X频段LTCC带通滤波器的插入损耗分别<2.5 d B和<3 d B,体积分别为6 mm×3 mm×1.1 mm和3.1 mm×2 mm×1.1 mm,小型化效果明显。     

基于LTCC技术的低通滤波器快速设计与测试方法

介绍了一种通带为0-1.2 GHz的LTCC多层低通滤波器快速设计方法。利用滤波器设计软件,通过选择相应的参数,可以快速地设计出低通滤波器电路图,再将原型电路在三维电磁场仿真软件HFSS中建立滤波器模型。根据厂商提供的电容、电感等元器件模型库,根据模型库中的电容、电感值估算本次设计所需的元件大小,在HFSS中可以快速的建立模型,仿真结果可以很快的满足指标要求。最后采用标准LTCC工艺实现出尺寸为3.2 mm×1.6 mm×1.0 mm的低通滤波器。运用该方法可以帮助工程师快速地设计LTCC滤波器,有很强的实用性和便利性。     

LTCC微波带通滤波器集总电路模型研究

通过引入不同的导纳变换器,提出了基于LTCC(low temperature cofired ceramics)技术的电容性耦合、电感性耦合、电容-电感混合耦合的微波带通滤波器集总电路模型,每一种模型都给出了具体的设计公式.从理论上分析了三种模型各自的优缺点,并用电路仿真软件ADS进行验证,为集总参数元件微波带通滤波器的电磁仿真和实际制作提供了理论依据.     

LTCC微波元件的结构模型研究与设计

LTCC技术是实现电子元器件小型化、片式化、高频化、集成化的新型关键技术,广泛用于元件、器件、基板、封装等领域,具有广阔的应用市场和发展前景。本文阐述了LTCC技术特点,并从LTCC微波电容、微波电感及微波滤波器方面对其结构模型设计进行了分析,提出通过合理集成可有效制作LTCC无源功能模块的思路。     

小型化宽阻带LTCC微波低通滤波器的设计与研制

先根据滤波器衰减量要求,理论分析确定滤波器的阶数及电路原理图,再用ADS软件优化仿真获得电路元件初始值,然后采用微波电磁场仿真软件HFSS对滤波器物理模型优化仿真,成功设计了一款3 d B截止频率为1 750 MHz、宽阻带频率2 035~6 700 MHz范围内衰减量大于20 dB的LTCC微波低通滤波器,并采用LTCC工艺制备该微波低通滤波器,尺寸为3.2 mm×1.6 mm×0.9 mm。制备样品实测结果与仿真吻合,说明采用该方法设计、研制小型化宽阻带LTCC微波低通滤波器是可行的。     

LTCC双频带通滤波器小型化设计与研究

选择用半集总结构搭建两个带通滤波器,通过引入电感电容的方式构建简单的匹配网络,将两个带通滤波器组合成一个双频滤波器。在ADS软件上对等效电路模型进行仿真,再用仿真软件HFSS搭建三维电感、电容模型,提取有效元件值进行拟合优化,最终达成预定技术指标。本款LTCC双频滤波器第一通带为380~560 MHz,第二通带为1 400~1 800 MHz,产品尺寸为3.2 mm×6.5 mm×2.3 mm。     

一种5G通信用LTCC带通滤波器的设计与实现北大核心CSCD

基于低温共烧陶瓷(LTCC)技术,使用HFSS三维电磁场软件设计仿真了一种5G通信用LTCC带通滤波器。该带通滤波器使用电感耦合和电容耦合双耦合原理,采用半集总结构设计,经过设计仿真优化,结合LTCC产线制程工艺,制备完成了一款小型化5G通信用滤波器。测试仿真结果对比:实际测试结果和仿真设计结果接近,滤波器中心频率为3.5 GHz。该滤波器适用于5G通信领域终端设备。     

多层LTCC带通滤波器的设计

LTCC技术具有可实现高密度电路互连、内埋置无源元件、延迟小以及优良的高频特性与可靠性，目前正成为微波与射频等通讯领域常用的技术之一。本文给出了设计多层LTCC带通滤波器的一般步骤，设计时所需注意的事项，并利用HFSS对中心频率为2450GHz，带宽为100MHz的滤波器进行了仿真模拟。讨论了采用平行耦合圆杆带状线电感、电容的实现，给出了电路模拟和仿真模拟的结果．     

Pi型电感耦合LTCC滤波器的寄生感性耦合研究

对二阶Pi型电感耦合LTCC滤波器中各个元件的电容及电感寄生效应进行了分析,提出了一种新的寄生电感耦合分析方法,并根据分析结果设计了一个二阶Pi型电感耦合和一个二阶Pi型电容耦合LTCC带通滤波器,其中,电感耦合滤波器的设计指标为:中心频率2.45GHz,相对带宽32.65%,带内插入损耗2dB,回波损耗18 dB;电...     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.