Ferroelectric tunable coplanar waveguide components for Ku- and K-band and applications

Abstract

The main objective of this research is to study the effect of inserting a Barium Strontium Titanate (BSTO) ferroelectric tuning layer in coplanar waveguide (CPW) and conductor-backed CPW (CBCPW) components. The modeled components include CPW and CBCPW transmission lines (with and without a dielectric filling between the center conductor and the ground planes). We have modeled the characteristic impedance (Z₀), effective dielectric constant (ε_eff), attenuation and dispersion as a function of circuit geometry and the ferroelectric thin-film's dielectric properties over the 10–20 GHz frequency range. We found that the presence of a ferroelectric layer between the transmission line and the ground planes improves the percentage change in ε_eff by almost two-fold with respect to a CPW deprived of this layer. This result is significant, as one could obtain larger frequency tunability with relatively lower applied fields compared to regular CPW or microstrip lines.     

Ferroelectric Thin Films-Based Technology for Frequency- and Phase-Agile Microwave Communication Applications

This paper deals with the current status of thin film ferroelectric-based frequency and phase agile microwave devices for communication applications. Researchers around the world have been active in this area for several years, and their results have been very relevant in determining the advantages and limitations of this technology when contrast with technology currently in use. The aforementioned results will be discussed in terms of device parameters such as RF losses, tunability, phase shift, frequency of operation, ease of fabrication, and projected cost, amongst others. Although the presentation will emphasize a NASA perspective, the information provided should offer a perspective of the attributes of this technology for other government agencies' electronically steerable electronics requirements, and for commercial communication applications.     

Microwave Tunable Components and Subsystems Based on Ferroelectrics: Physics and Principles of Design

The most promising microwave ferroelecric device is a ferroelectric phase shifter, aimed to be an element of a phased-array antenna. The following characteristics of the phase shifter are important: microwave insertion loss, range of operational temperatures, life time. Designing microwave tunable components is based on carefully developed models of ferroelectrics and appropriate software of the circuit design. The quality of a phase shifter is determined by the figure of merit ( F ) defined as a ratio phase shift/insertion loss and measured in deg/dB. For competitive applications one needs F = 200-300 deg/dB. An extended temperature range of operation is urgently required. There are the following ways of improvement of the ferroelectric phase shifters: i) utilizing an appropriate chemical compound of ferroelectric material, ii) developing the structure of the device, for example, the film with a variable composition factor, iii) application of the digital mode of operation.     

并联型有源滤波器的重复学习控制策略参数分析与设计

为了消除谐波抑制过程中重复学习控制器不稳定因素对控制品质的影响,论文以LCL滤波器的有源电力滤波器系统稳定性和补偿性能作为切入点,理论分析了重复学习控制器的参数选取范围,同时仿真结果验证了该理论的正确性和有效性.     

XCP三路频分复用信号有源滤波器的设计及其PSpice仿真分析

XCP(投弃式海流剖面测量仪)三路频分复用信号的滤波分离是863计划支持的“XCP投弃式剖面测量技术研究”这一课题的关键研究部分之一.详细介绍了采用有源滤波技术分别设计三路信号滤波器的方法,并使用PSpice电路仿真软件对滤波器的滤波特性进行了仿真分析,仿真结果证明所设计的滤波器电路对实现XCP水下三路频分复用信号的安全分离是可行的.     

Development of Ferroelectric Ceramics with High Dielectric Constant and Low Dissipation Factor for High-Voltage Capacitors

Both ferroelectric BaTiO₃-based and SrTiO₃-based dielectric ceramics with high dielectric constant and low dissipation factor have been successfully developed, and applied into mass production for high-voltage ceramic capacitors. Crystalline phases of the ceramics were identified by XRD. STEM study of the ceramics was also conducted. Based on the computer simulation of a shell-core and two-phase mixed structural model proposed, a novel processing method was employed to produce SrTiO₃-based ceramics with the following satisfactory dielectric properties: dielectric constant at room temperature _20C=2000, dissipation factor at room temperature D _20C=0.003, temperature coefficient of dielectric constant = –8% (–25°C to 85°C), and, breakdown electric field E _b=10kV/mm(dc). Optional composition of BaTiO₃-based ceramics has been obtained through the orthogonal design experimentation: BaTiO₃-xBaZrO₃-yBaSnO₃, where x = 8wt% and y = 6wt%, with minor additions of MnSiO₃, WO₃, CeO₂, Bi₂(SnO₃)₃ and ZnO. Its major properties are as follows: Curie temperature T _c = 21°C, _20C=18,000, D _20'C = 0.008, =–80% (–25°C+85°C) and E _b = 8kV/mm (dc).     

物联网技术在输变电设备管理中的应用

输变电设备是电网的重要构成元件,其自身可靠性是电网安全运行的基本保证.输变电设备的智能监测与评估管理是智能电网建设的重要组成部分,通过积极地引入物联网技术,有助于提升设备监测诊断、运行管理的水平,推进智能电网建设.文章总结了国内外输变电设备状态监测与全寿命周期管理的研究现状,结合物联网技术,详细介绍了物联网技术在输变电...     

开关电源输入端保护元件及电路设计

首先对开关电源常用特种元器件的类型及主要功能做一简介,然后重点阐述开关电源输入保护电路及EMI滤波器的设计。     

Planar and Parallel Dielectric Properties of Compositionally Graded (Ba,Sr)TiO3 Thin Films for Tunable Microwave Applications

Compositionally graded (Ba_x,Sr_{1 ? x})TiO₃ [BST] ferroelectric thin films have been received much attention in graded ferroelectric devices due to their unique properties, such as large pyroelectric coefficients, large polarization offset and small temperature coefficient of dielectric constant for microwave tunable devices. Compositionally graded BST thin films were deposited epitaxially on LaAlO₃ [LAO] and Nb-doped SrTiO₃ [STO:Nb] substrates by pulsed laser deposition. The planar and parallel dielectric properties of compositionally graded BST epitaxial thin films ware investigated in the frequency ranges of 100 Hz ～ 1 MHz as a function of the direction of the composition gradient with respect to the substrate at room temperature. The dielectric properties of the graded BST films depended strongly on the direction of the composition gradient with respect to the substrate. The graded ST → BT films grown on LAO and STO:Nb substrates exhibited a excellent dielectric properties than the graded BT → ST films.     

高校MIS中科研人员管理系统的设计与开发

介绍了研制开发“科研人员管理系统”应用软件的设想思想、软件构成、主要功能、特点及用ＦＯＸＰＲＯ语言实现该ＭＩＳ系统时所使用的各种技术。     

Development of Materials Integration Strategies for Electroceramic Film-Based Devices Via Complementary In Situ and Ex Situ Studies of Film Growth and Interface Processes

We review our studies of film growth and interface processes performed using complementary in situ and ex situ characterization techniques that provide valuable information critical to the development of materials integration strategies for the fabrication of electroceramic film-based devices. Specifically, we review our work performed using in situ time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) / X-ray photoemission spectroscopy (XPS) / spectroscopic ellipsometry (SE), in conjunction with ex situ TEM and other techniques to study film growth and interface processes critical to the fabrication of non-volatile ferroelectric memories (NVFRAMs), dynamic random access memories (DRAMs), and high frequency devices based on high-K thin films. TOF-ISARS involves three distinct but closely related experimental methods, namely: ion scattering spectroscopy, direct recoil spectroscopy and mass spectroscopy of recoiled ions, which provide monolayer-specific information on film growth and surface segregation processes. Spectroscopic Ellipsometry enables investigation of buried interfaces. XPS provides valuable information on the chemistry of surface and interfaces. Specifically, we discuss: a) studies of oxidation of Ti-Al layers and synthesis and properties of La 0.5 Sr 0.5 CoO 9 /Ti-Al heterostructured layers for integration of PZT capacitors with Si substrates, and b) studies of BaSr x Ti 1 m x O 3 layer integration with Si substrates relevant to DRAMs, high frequency devices and high-K gate oxides for integrated circuits. This review shows the power of combined in situ / ex situ analytical techniques to provide valuable information for material integration strategies for electroceramic thin film-based devices.     

智能电能表现场校验仪的开发与设计

介绍了CP2102接口技术和智能电能表现校仪的开发。结合PDA（个人数字助理）、计算机及无线通信技术,使用Delphi、EVC开发工具,在Oracle8i开发的关系型数据库基础上。设计开发了一种电能表现场校验与管理智能系统,实现了电力校表的无纸化工作和智能化管理。     

车用电机系统磁阻式旋变转子设计与分析

介绍了车用电机系统磁阻式旋变的工作原理及转子凸极分析设计方法。该方法可快速地进行转子凸极形状设计,并在此基础上借助有限元进行旋变磁场的精确计算、误差分析以及转子凸极尺寸的精确修正。样机的试验结果验证了该设计方法的有效性。     

水电站群发电调度决策支持系统的设计与开发

介绍了电网水电站群发电调度决策支持系统的结构、功能和特点。该系统基于客户/服务器(Ｃ/Ｓ)模式,使用多文档界面(MDI)风格，模型系统可成功解决大规模水电系统的径流预报和发电调度问题。概率调度和函数调度为调度决策提供了参考。灵活和实用的方案分析、图表联动和报表功能方便了系统管理和用户日常操作。考虑了抽水蓄能的优化问题和调度风险分析，系统具有更好的通用性、安全性和可扩展性，适合各类水调系统。     

高压大功率场合LCC谐振变换器的分析与设计

具有电容型滤波器的LCC谐振变换器十分适用于高压大功率场合,由于具有三个谐振元件,变换器在工作中呈现出多谐振的过程,使得分析与设计繁琐复杂.本文分析了其工作原理,采用基波近似法得到了该变换器的等效交流电路,在此基础上推导了它的数学模型,提出了一种详尽的设计方法,该方法简单、直观并且准确,可以保证所有开关管在全负载范围内实现零电压开关,减小电流应力、轻载环流和开关频率的变化范围.通过一台输入100V,输出16.5kV/230mA,采用变频控制的样机验证了设计的正确性.     

航天电源控制器集成模块的控制策略及参数设计方法

在航天器太阳电池阵——蓄电池电源系统中,采用新型电源控制器(PCU)集成模块替代原有PCU中的多个功率调节器,可以简化电路结构,降低系统成本。但是PCU集成模块的控制策略需要改进,并且电路参数设计更加复杂。提出该模块在两种不同续流方式时的控制策略,并对其中的分域控制和双频率PWM控制进行详述。在此基础上,通过详细分析不同工作模式时的输入、输出特性,提出PCU集成模块的电路参数设计方法。最后,搭建了一套110W的原理样机并进行了实验验证。     

用于模拟游梁式抽油机电动机动态负荷的测试系统设计及应用

抽油机电动机(beam pumping motor,BPM)负荷具有周期性动态变化特点,对于此类工况下的电动机能效检测通常采用标准井测试方法,该方法存在负载单一、通用性差等局限性,难以灵活地模拟油田复杂的负荷特性。为解决这一问题,以国内外油田广泛应用的游梁式抽油机为例,建立了抽油机系统(beam pumping system,BPS)数学模型并分析了模型参数对仿真误差的影响;在此基础上,提出一种通过调整平衡配重及井下摩擦力参数值大小来补偿模型误差的技术手段,并通过遗传算法(genetic algorithms,GA)对上述参数进行优化求解;进一步基于该模型开发出一套室内BPM模拟加载测试系统,该系统采用由四象限变频器与伺服电机组成的能量回馈式单元作负载,仅通过改变上位机BPS模型参数便可实现不同动态负荷的精确模拟。与现场测试结果对比表明,该系统可模拟抽油机空载、轻载及重载工况下的动态负荷特性,误差低于2%,系统节电率达87%。文中研究成果可为油田电机选型及能效动态评估提供重要技术支持。     

浮点协处理器设计及其在电力电子数字控制平台中的应用

由于定点数字信号处理器(digital signal processor,DSP)存在字长效应和运算能力不足的问题,在一些电力电子应用场合不得不采用浮点DSP。为了解决定点DSP的电力电子数字控制平台的计算瓶颈问题,该文提出了用现场可编程逻辑阵列配置浮点协处理器的方法来提升平台的计算能力。该文给出了浮点运算单元的详细设计过程,并提出了一种更为简单的浮点除法算法实现方法,该算法的误差分析表明：最大绝对值误差不超过2个最小位。仿真和实验验证该浮点协处理器的运算速度可达2.5千万次浮点运算。用快速傅里叶变换算法测试运算效率的实验表明：浮点协处理器的运算效率比DSP算法运算效率快5倍之多。     

电子式互感器校验仪的设计与实现

目前我国对电子式互感器的校验尚无统一的标准,传统的电磁式互感器校验仪已不能胜任电子式互感器的校验工作,为了使新型电子式互感器产品顺利进入电力市场以确保电力系统安全可靠地运行,迫切需要研制电子式互感器校验仪。本文设计和实现了一种以DSP和FPGA为硬件平台的电子式互感器校验仪,它具有操作方便,功能多样,体积小,便于携带等优点;比差与相差的计算中采用了加窗插值FFT(快速傅里叶变换)算法,有效地抑制了因电网频率波动而导致的非整周期采样对校验结果的影响,满足了校验仪的精度要求。