C波段超宽带微型LTCC带通滤波器设计

基于低温共烧陶瓷(Low temperature co-fired ceramic,LTCC)技术设计了一款C波段超宽带、高抑制的带通滤波器,并通过LTCC技术对滤波器进行加工制作,满足了小体积、高性能、密集封装的应用需求。滤波器整体上采用了低通滤波器与高通滤波器串联的结构实现超宽通带,并引入传输零点来增加带外抑制,采用垂直叉指电容和双层螺旋电感来减少滤波器体积。最终实现的滤波器通带的中心频率为5.3 GHz,带宽为3 GHz,通带内插损小于0.8 dB,在DC～3 GHz处抑制达到了36 dB,在8～14 GHz处抑制达到了35 dB,通带回波损耗为12 dB。滤波器体积为：1.8 mm×1.0 mm×0.7 mm。     

一种识别雷达用半集总参数LTCC双工器

介绍了一种基于低温共烧陶瓷(LTCC)工艺研制而成的小型化半集总高隔离度双工器.该双工器由L波段集总参数低通滤波器和X波段阶跃阻抗( SIR)分布参数带通滤波器组成.通过电磁仿真软件的仿真优化,实际加工滤波器的测试结果与软件仿真结果吻合.其中低通滤波器1dB截止频率为1.46GHz,带通滤波器中心频率为8.3GHz,1dB带宽为0.6GHz,通带内插损小于3.5dB,X波段端口对L波段端口隔离度大于60dB.该小型化LTCC双工器已成功应用于某毫米波战场识别系统的T/R组件中.     

高度边带陡峭的半集总LTCC滤波器设计

基于LTCC技术设计一款高度边带陡峭的带通滤波器。为了便于生产加工,选用半集总结构,采用LTCC技术保证了此款带通滤波器的小型化。通过交叉耦合插入零点的方式提高边带陡峭度,为了满足高度边带陡峭的特性要求,选择上下层模式,级联两个一致的带通滤波器。电路仿真与电磁场三维仿真结果均优于设计指标。此款带通滤波器中心频率在1 237.5MHz,带宽575MHz,100~480MHz频率上的衰减均优于40dB,1 900~3 050 MHz频率上的衰减均优于30dB,尺寸仅为4.5mm×3.2mm×2.5mm。     

高度边带陡峭的半集总LTCC滤波器设计北大核心CSCD

基于LTCC技术设计一款高度边带陡峭的带通滤波器。为了便于生产加工,选用半集总结构,采用LTCC技术保证了此款带通滤波器的小型化。通过交叉耦合插入零点的方式提高边带陡峭度,为了满足高度边带陡峭的特性要求,选择上下层模式,级联两个一致的带通滤波器。电路仿真与电磁场三维仿真结果均优于设计指标。此款带通滤波器中心频率在1 237.5MHz,带宽575MHz,100~480MHz频率上的衰减均优于40dB,1 900~3 050 MHz频率上的衰减均优于30dB,尺寸仅为4.5mm×3.2mm×2.5mm。     

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。     

一种新颖羊角形缺陷地结构宽带带通滤波器

为了得到小型化的带通滤波器,该文提出了一种新的羊角形缺陷地结构(DGS),并将其与耦合开路枝节线结合,设计并制作了一种新型宽带带通滤波器。该带通滤波器的中心频率为7.95GHz,3dB通带为5.25~10.65GHz,相对带宽达到了68%。与以往的宽带带通滤波器相比,它具有结构简单,尺寸小的特点,仿真和测量结果吻合较好。     

微型LTCC四级带通滤波器的设计

提出了一种微型LTCC四级带通滤波器的实现方法。该带通滤波器由四个性能良好的谐振器组成,通过交叉耦合实现传输零点从而达到良好的阻带衰减。通过电路仿真以及电磁场三维仿真软件进行三维建模,对模型进行加工测试,滤波器的测试结果与电磁仿真结果相匹配。四级带通滤波器的中心频率为5.25GHz,带宽为500 MHz,通带范围内插入损耗均优于1.59dB,在0~4.65GHz频率以及6.33GHz频率以上的带外衰减均优于40dB,尺寸仅为2.5mm×3.2mm×1.5mm。本设计采用了带状线分布式结构来实现滤波器的微型化。     

基于DGS 结构的微带岔线型带通滤波器设计

本文介绍了一种基于缺陷地结构(DGS)的微带岔线型宽带带通滤波器的设计过程。此滤波器以四分之一波长的开路枝节型带通滤波器为原型进行设计和改进,引入了微带岔线和DGS 结构,在增加通带带宽和阻带带宽的同时,使滤波器的带外谐波抑制和带内回波损耗得到了很大的改善。采用HFSS 三维场仿真软件进行S 参数的仿真,从仿真结果可 以看出,所设计的带通滤波器中心频率为11.5GHz,其3dB 相对带宽大于50%,带内插损小于0.3dB。此外,在1-6GHz的第一阻带内,滤波器的带外抑制大于20dB,最大抑制度为52dB;在15-24GHz 的第二阻带内滤波器的带外抑制大于20dB,最大抑制度为46dB。整个滤波器尺寸仅为12mm × 16mm。     

一种基于DGS和EBG混合结构的毫米波滤波器设计

设计了一款可应用于毫米波频段（22.5～29.5 GHz）的小型化、高性能带通滤波器。首先利用羊角型DGS结构的谐振特性,在基片集成波导（Substrate integrated waveguide,SIW）的高通通带内产生阻带和低通特性;之后在滤波器输入微带线上耦合U型电磁带隙结构（Electromagnetic band gap,EBG）,利用该结构产生的两传输零点之间的带宽可以调整的特性,来保证滤波器通带带宽及提供高带外抑制;最后利用电磁仿真软件HFSS 13.0对滤波器进行仿真与优化。实测结果表明,该滤波器整体尺寸为10 mm×5 mm,中心频率为26 GHz,3 dB截止频率分别为22.1 GHz和29.3 GHz,带宽为7.2 GHz,相对带宽达到了28%,滤波器的插入损耗为1 dB,回波损耗优于15 dB,上、下边带带外抑制均优于25 dB,可应用于毫米波频段无线通信系统中。     

小型化三维发夹型LTCC宽带带通滤波器

利用低温共烧陶瓷(LTCC)工艺,通过通孔互联实现了三维结构的发夹型宽带带通滤波器。该结构将谐振单元的横向尺寸转移到z轴方向实现,有效减小了滤波器的尺寸并且谐振器间的耦合系数为传统结构的1.6倍。利用五个谐振器结构实现较宽的频带(>30%)和较好的选择特性。设计并实际制作了中心频率10 GHz的LTCC带通滤波器,3 dB带宽为8.8～12.1 GHz,实测指标与设计仿真结果较为吻合。     

聚对苯撑苯并双(口恶)唑发光及其器件制备

采用光谱技术,研究了聚对苯撑苯并双(口恶)唑(PBO)溶液的光敏发光特性,并用相对法估算出溶液发光效率在50%范围.结合光谱技术、半导体电学和电化学等研究手段,具体研究了以PBO为发光层的单层电致发光器件,研究结果显示,电致发光与薄膜的光致发光有具有相同的发光中心,峰值位于510 nm左右.同时发现,由于存制备过程中不同处理条件使得不同厚度薄膜残留的掺杂物质浓度不同,从而引起薄膜的导电性的不同.使得器件的阈值场强随PBO厚度的减小而逐渐增加.     

系统级封装新型埋入式电源滤波结构的研究

在高密度小尺寸的系统级封装(SiP)中,对供电系统的完整性要求越来越高,多芯片共用一个电源网路所产生的电压抖动除了会影响到芯片的正常工作,还会通过供电网路干扰到临近电路和其他敏感电路,导致芯片误动作,以及信号完整性和其他电磁干扰问题.这种电压抖动所占频带相当宽,几百MHz到几个GHz的中频电源噪声普通方法很难去除.结合埋入式电容和电源分割方法的特点,提出一种新型高性能埋入式电源低通滤波结构直接替代电源/地平面.研究表明,在0.65～4GHz的频带内隔离深度可达-40～75 dB,电源阻抗均在0.25ohm以下,实现了宽频高隔离度的高性能滤波作用.分别用电磁场和广义传输线两种仿真器模拟,高频等效电路模型分析这种低通滤波器的工作原理以及结构对隔离性能的影响,并进行了实验验证.     

Emerging interconnects: a state-of-the-art review and emerging solutions

Aluminium was a primary material for interconnection in integrated circuits (ICs) since their inception. Later, copper was introduced as interconnect material which has better metallic conductivity and resistance to electromigration. As the aggressive technology scaling continues, the copper resistivity increased because of size effects, which causes increase in delay, power dissipation and electromigration. The need to reduce the resistor-capacitor??????? delay, dynamic power utilisation and the crosstalk commotion is as of now the fundamental main impetus behind the presentation of new materials. The purpose of this paper is to do a survey of interconnect material used in IC from introduction of ICs to till date. This paper studies and reviews new materials available for interconnect application which are optical interconnects, carbon nanotube (CNT), graphene nanoribbons (GNRs) and silicon nanowires which are alternatives to copper. While doing a survey of interconnect material, it is found that multiwalled CNTs, multilayer GNR and mixed CNT bundles are promising candidates and are ultimate choice that can strongly address the problems faced by copper but on integration basis copper would last for coming years.     

Arsenic deposition as a precursor layer on silicon (211) and (311) surfaces

We investigate the properties of arsenic (As) covered Si(211) and Si(311) surfaces by analyzing data from x-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED) images. We then create a model using total surface energy calculations. It was found that both Si(211) and Si(311) had 0.68±0.08 surface As coverage. Si(211) had 0.28±0.04 Te coverage and Si(311) had 0.24±0.04 Te coverage. The Si(211) surface replaces the terrace and trench Si atoms with As for a lower surface energy, while the Si edge atoms form dimers. The Si(311) surface replaces all terrace atoms and adsorbs an As dimer every other edge site. These configurations imply an improvement in the mean migration path from the bare silicon surface by allowing the impinging atoms for the next epitaxial layer, tellurium (Te), to bind at every other pair of edge atoms, and not the step terrace sites. This would ensure a nonpolar, B-face growth.     

光子晶体微腔发光二极管

光子晶体微腔因其具有增强自发辐射、定向输出和单模工作的能力而受到广泛关注。介绍了光子晶体微腔发光二极管的基本原理、设计、特性、制作及其典型器件。     

Comparative study of maximum power point tracking techniques for hybrid renewable energy system

The power generation demand is increasing day-by-day throughout the world, therefore, the use of hybrid systems becomes a significant solution. The hybrid renewable energy system (HRES) is used for delivering power in various regions in order to overcome intermittence of wind and solar resources. Because of increasing environmental problems, for example, greenhouse gas emission and energy cost have interested novel research into substitute methods in favour of electrical power generation. Maximum Power Point Tracking (MPPT) control method is a vast deal of novel research used for enhancing the efficiency of HRES. The authors have revealed that the hybrid techniques i.e. Global MPPT, fuzzy-neuro systems, Adaptive Neuro-Fuzzy Inference System (ANFIS), Perturbed and Observe (P&O) + Adaptive Neural Network (ANN) etc. can provide best results as compared to other MPPT control methods. This paper offering a state of art review of MPPT control techniques for HRES.     

用于单光子TOF测量的时间-幅度变换器

基于新型共源共栅电流源的积分方法,设计了一种用于单光子飞行时间(TOF)测量的时间-幅度变换器(TAC)。该方法有效简化了TAC电路结构,减小了TAC占用面积,显著提高了TOF的满量程范围(FSR)。采用0.18 μm标准CMOS工艺设计。集成TAC的单光子探测器像素单元的填充因子可达到26.8%。后仿真结果表明,该TAC在120 ns的FSR内具有230 ps的定时分辨率,微分非线性(DNL)低于0.05 LSB,积分非线性(INL)低于1.1 LSB。蒙特卡洛仿真表明,512个TAC像素间的不均匀性低于0.5 %。该TAC非常适用于高密度时间相关的单光子计数(TCSPC)探测器阵列。     

Joint estimation of TOA and DOA in IR-UWB system using a successive propagator method

Impulse radio ultra-wideband (IR-UWB) ranging and positioning require accurate estimation of time-of-arrival (TOA) and direction-of-arrival (DOA). With receiver of two antennas, both of the TOA and DOA parameters can be estimated via two-dimensional (2D) propagator method (PM), in which the 2D spectral peak searching, however, renders much higher computational complexity. This paper proposes a successive PM algorithm for joint TOA and DOA estimation in IR-UWB system to avoid 2D spectral peak searching. The proposed algorithm firstly gets the initial TOA estimates in the two antennas from the propagation matrix, then utilises successively one-dimensional (1D) local searches to achieve the estimation of TOAs in the two antennas, and finally obtains the DOA estimates via the difference in the TOAs between the two antennas. The proposed algorithm, which only requires 1D local searches, can avoid the high computational cost in 2D-PM algorithm. Furthermore, the proposed algorithm can obtain automatically paired parameters and has better joint TOA and DOA estimation performance than conventional PM algorithm, estimation of signal parameters via rotational invariance techniques algorithm and matrix pencil algorithm. Meanwhile, it has very close parameter estimation to that of 2D-PM algorithm. We have also derived the mean square error of TOA and DOA estimation of the proposed algorithm and the Cramer-Rao bound of TOA and DOA estimation in this paper. The simulation results verify the usefulness of the proposed algorithm.     

超宽带脉冲信号的光学生成方法研究

近年来超宽带(UWB)通信技术迅猛发展,在测量、雷达技术、民用和军事无线通信中有着重要的应用,UWB-over-fiber技术已经成为目前研究的热点,其中就包括UWB脉冲信号的产生方法。区别于传统的电子学方法,光子学产生方法不受电子瓶颈制约,可以实现很高的带宽,并且具有抗电磁干扰、重量轻、结构紧凑的优点。通过对比国内外本领域研究成果,讨论及总结了以下三种原理的UWB脉冲信号的光学生成方法:1)相位调制-强度调制转换(PM-IM);2)半导体光放大器(SOA)的非线性效应;3)频谱塑形和色散所致频域-时域映射,然后对各种方案进行了对比分析。     

多孔硅发光机制的分析

从量子力学的基本理论出发讨论了量子限制效应，推导出多孔硅有效禁带宽度增量并用量子限制效应和表面态及其物质在发光中作用的理论解释了ＰＳ光致发光的实验现象。