Tuning in to RF MEMS

RF MEMS technology was initially developed as a replacement for GaAs HEMT switches and p-i-n diodes for low-loss switching networks and X-band to mm-wave phase shifters. However, we have found that its very low loss properties (high device Q), its simple microwave circuit model and zero power consumption, its high power (voltage/current) handling capabilities, and its very low distortion properties, all make it the ideal tuning device for reconfigurable filters, antennas and impedance matching networks. In fact, reconfigurable networks are currently being funded at the same level-if not higher-than RF MEMS phase shifters, and in our opinion, are much more challenging for high-Q designs.     

基于CC1020加功率放大器的射频收发模块设计

随着无线通信技术的发展,无线数传系统成为1个重要的发展方向.针对无线数传系统中单片射频收发芯片在远距离通信方面存在的不足,本文介绍了1种由CC1020无线收发芯片与功率放大器PA2460组成的射频收发系统模块设计方案.该模块具有低功耗、体积小的特点,并可方便地集成到各种无线测控系统中.本文详细阐述了设计思路并给出硬件电...     

电力系统中的微波保护技术

文章介绍了电力系统中的微波保护技术的原理、组成及发展,并阐述了微波保护作为电力系统的保护形式的优点及需解决的一些技术问题。     

Microwave AlGaN/GaN HFETs

This article presents the operating physics, performance potential, and status of device development of microwave AlGaN/GaN heterostructure field-effect transistors. AlGaN/GaN HFETs show potential for use in improved RF performance microwave amplifier applications. Development progress has been rapid, and prototype devices have demonstrated RF output power density as high as 30 W/mm. Microwave amplifier output power is rapidly approaching 100 W for single-chip operation, and these devices may soon find application for cellular base station transmitter applications. Devices are being developed for use in X-band radars, and RF performance is rapidly improving. The HFET devices experience several physical effects that can limit performance. These effects consist of nonlinearities introduced during the high-current and high-voltage portions of the RF cycle. High-current phenomena involve the operation of the conducting channel above the critical current density for initiation of space-charge effects. The source resistance is modulated in magnitude by the channel current, and high source resistance results. High voltage effects include reverse leakage of the gate electrode and subsequent charge trapping effects on the semiconductor surface, and RF breakdown in the conducting channel. These effects can produce premature saturation effects. Also, under certain conditions, high voltage operation of the device can initiate an IMPATT mode of operation. When this occurs, the channel current increases and RF gain is increased. This phenomenon enhances the RF output power of the device. The physical limiting effects can be controlled with proper design, and the outlook for use of these devices in practical applications is excellent.     

农网营销系统新技术

结合近年来信息技术领域出现的新技术、新产品,概括了农网营销系统的软件体系结构、软件开发平台、网络通信技术,介绍了完全B/S结构的电力营销管理信息系统、网络报表系统、虚拟局域网技术、低压载波集中抄表系统等几种在农网营销系统领域采用计算机技术的新产品。     

EtherCAT总线技术在现代电力电子装置中的应用

随着中国智能电网的发展,电力电子技术在电力系统中得到广泛应用。模块化多电平（MMC）拓扑是目前高压、大容量电力电子装置的主要方案之一,传统集中式控制系统框架的缺点日显。通过对EtherCAT总线技术实时性、同步性、灵活性的分析,针对模块化多电平拓扑的一种H桥级联,提出了一种基于EtherCAT技术的分布式控制系统框架。搭建了9模块H桥级联平台,通过实验证明了EtherCAT总线控制系统的优良性能。根据实践经验,概括了许多应用EtherCAT技术的关键点,该分布式控制系统构建同样适用于其他的模块化多电平电力电子装置。     

ADF4350低相噪频率合成器在射频无线通信设备中的应用

现代射频和微波电子系统中要求频率源具有高频低相噪,且具有可靠性好、体积小、功耗低的特点。ADF4350频率合成器具有全集成、低相位噪声的优点,内置片上VCO（压控振荡器）与PLL（锁相环）,可以工作在极宽的连续频率范围内,广泛用于无线基础设备及测试设备,无线LAN,CATV和时钟发生器中。本文简要介绍了ADF4350的主要功能,详细给出了基于ADF4350用作直接变换调制器以及和ADuC812,ADSP-21xx的接口连接的设计方案。     

电力光纤到户在内蒙古电网试点建设的可行性分析

介绍了配电网自动化系统在包头地区试点建设的成功经验,基于电力通信系统向用户侧及低压侧的延伸与拓展,智能电网及需求侧集成技术的成熟与发展,提出了通过以配电网自动化通信系统构架及EPON光网络系统为支撑、在内蒙古试点建设直接面向终端用户的电力光纤,即光纤到户,并对其可行性和必要性进行分析。分析认为：电力光纤到户在内蒙古电网试点建设具有可行性,有利于提高配电网自动化程度,延伸配电网向低压侧及用户侧的控制能力,促进配电网、集抄、电力通信等传统业务的融合,提高内蒙古电网的智能化水平。     

一种射频功率检测控制系统的设计方法

介绍了一种宽频带射频功率检测控制系统的设计方法。采用2个支线形式的微带定向耦合器,耦合主通道不同频带的收发信号。通过CPU控制8个射频开关,实现收发信号切换、定向耦合器选择、以及收发信号分离滤波。收发信号的功率检测是通过定向耦合器将主通道的射频信号耦合到检波通道,经信号选择、滤波、放大后进入AD8362,转换为电压信号,然后经CPU的数模转换、查表补偿后上报功率。若检测到接收信号功率大于设置值,自动电平控制启动,CPU配置数控衰减器,将接收信号衰减到设置值以下,实现了收发通道射频信号功率检测上报、自动电平控制,以及多频段兼容。在实际工程设计中,为射频系统架构和电路设计人员,提供参考和依据。     

Development of radio frequency transmitters including on‐chip antenna for intelligent human sensing systems

This paper presents the essentials of the development of an integrated smart microsensor system that has been developed to monitor the motion and vital signs of humans in various environments. Integration of RF transmitter technology with complementary metal‐oxide‐semiconductor/micro electro mechanical systems (CMOS/MEMS) microsensors is required to realize wireless smart microsensors for the monitoring system. Sensors for the measurement of body temperature, perspiration, heart rate (pressure sensor), and motion (accelerometers) are candidates for integration on the wireless smart microsensor system. In this paper, the development of radio frequency transmitter (RF) that will be integrated on wireless smart microsensors is presented. A voltage controlled RF‐CMOS oscillator (VCO) has been fabricated for the 300‐MHz frequency band applications. Also, spiral inductors for an LC resonator and an integrated antenna have been realized with a CMOS‐compatible metallization process. The essential RF components have been fabricated and evaluated experimentally. The fabricated CMOS VCO showed a conversion factor from voltage to frequency of about 81 MHz/V. After matching the characteristic impedance (50 Ω) of the on‐chip integrated antenna and the VCO output, more than 5 m signal transmission from the microchip antenna has been observed. The transmitter showed remarkable improvement in transmission power efficiency by correct matching with the microchip antenna. Essential technologies of the RF transmitter for the wireless smart microsensors have been successfully developed. Also, for the 300‐MHz band application, the integrated RF transmitter, with the CMOS oscillator and the on‐chip antenna, has been successfully demonstrated for the first time. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

2014年国际大电网会议学术动态系列报道高压直流输电和电力电子技术

介绍了2014年国际大电网委员会(CIGRE)高压直流输电和电力电子技术专委会(SC B4)的主要专题和论文,涉及的技术领域包括:高压直流输电技术的发展;灵活交流输电(FACTS)装置研发及技术发展;电力电子技术在可再生能源并网领域的应用;高压直流输电工程应用中的一些典型问题等。     

高频高压交流电源的研制

传统的工频升压高压电源体积和重量均很大且性能差、效率低,此外还对电网注入大量谐波,不适合科研及现代工业应用中的实际需要。为解决以上问题,研究了高频高压交流电源的系统结构及工作原理,采用先进的低压交流电弧技术、高频开关电源技术、单片机控制和阶段式电流保护技术,应用并改进新型电源电路拓扑结构,研制了一种应用于水中产生等离子体的高频高压交流电源。设计高频高压变压器是该电源的难点,对此进行了重点介绍并根据实测数据进行了电源的仿真分析,最后给出了样机的实测电压波形。实验结果表明,设计中应用的新型变换技术较好地解决了预研问题,从而证明了设计的可行性,为进一步完善电源系统提供了充分的依据。该高压电源频率10~30 kHz连续可调,具有体积小、重量轻、系统运行安全及控制方便等优点。     

Key Technologies for High Density FeRAM Applications

Ferroelectric random access memories (FeRAMs) are new types of memory devices especially suitable for mobile applications due to their unique properties such as non-volatility, small cell size especially with chain cell design, fast read and write as well as low voltage / low power behavior. Although standard CMOS processes can be used for frontend processes, FeRAM technology development has to overcome major challenges due to new materials used for capacitor formation. In this paper the advantages and disadvantages of different ferroelectric materials, especially in terms of low thermal budget for crystallization and capacitor formation, are discussed. In addition, major development issues for high-density applications like different capacitor encapsulation concepts to protect the capacitor form backend process damage and degradation by hydrogen are presented. Results from a recently developed 1T / 1C 8Mb FeRAM are discussed. The FeRAM is based on a 0.25 w m CMOS process. Due to the chain cell architecture a chip size of 76mm 2 was achieved using 2 metal layers.     

电力系统硬件在环仿真应用的现状及展望

硬件在环仿真(HILS)是提升现代大电网系统仿真准确性、支撑开展高压直流/新能源等装置可靠性验证的有效手段。首先,在介绍HILS基本架构和优势的基础上阐述了HILS在提升电网一次系统仿真准确性、支撑电网二次控制系统测试验证方面的技术及应用现状;然后分析了电力系统HILS平台构建面临的挑战,提出可接入多异构数据模型的灵活架构技术、有限仿真资源下新能源场站等值和大型二次系统等效技术、控制对象接入的通用接口技术等技术方向;最后,从传统技术深化和与新技术融合发展2个角度探讨了电力系统HILS的未来发展趋势,以期对相关平台研发和仿真实验工作提供一定参考。     

2010年国际大电网会议系列报道高压直流输电和电力电子技术

介绍了2010年国际大电网会议(CIGRE)高压直流输电和电力电子技术专委会(SC B4)的主要专题和论文,涉及的技术领域包括:高压直流输电技术的发展--特别是±800 kV特高压直流输电和基于电压源换流器的高压直流输电(VSC-HVDC)的最新工程进展;灵活交流输电(FACTS)装置的应用经验及新的工程情况;电力电子...     

低压电器的网络化技术

从可通信的智能低压电器、低压电器网络化控制系统、多总线融合技术和基于智能低压电器通信网的低压配电监控系统四方面介绍了低压电器网络化技术研究的内容和国内外研究,分析了为适应智能电网对低压供配电网的要求、低压电器网络化技术在各层次上面临的主要问题及解决思路。     

大功率电力电子开关用于配电变压器无弧有载调压方案

在总结已有相关技术经验的基础上,提出了基于大功率电力电子开关的无弧有载调压新方案.根据目前电力电子技术发展情况,分别介绍了无弧有载调压方案适用于高电压等级和低电压等级配电变压器的2种形式,并给出了相关仿真实验波形.针对所提出的方案建立了以单片机为核心的有载调压控制系统,并通过低压模型实验验证了此新型无弧有载调压方案能够在控制系统作用下无弧、快速、可靠地进行有载调压.     

Statistical forecasting algorithm on circuit level gain transformation due to negative bias temperature instability for the microwave frequency spectrum

Negative Bias Temperature Instability (NBTI) is a critical reliability issue for CMOS technology, as this directly impacts the CMOS circuit performance parameters causing system failure. Moreover, NBTI behavior for radio frequency (RF) signals needs more understanding. On the device level, there has been much research on the relation between NBTI and RF. Many of those works contradict each other on the question of RF dependency with NBTI. Hence, the behavior of NBTI must be analyzed at the circuit level using a prediction technique. In this article, we analyzed the circuit level impact of NBTI for microwave frequency and developed a gain transformation technique for RF circuits in the microwave frequency range. To do this, we employed a 65 nm conventional ring oscillator as an RF block and carried out an aging simulation on it. A compatibility analysis was performed on low and high bandwidth microwave signals. The implemented statistical technique can determine the actual operable frequency range, so that the RF circuit can perform with minimal NBTI effect.     

基于PSM技术的70kV/90A高压脉冲电源的研制

在受控核聚变实验中,辅助加热系统采用高功率微波和高能粒子对等离子体进行加热或驱动。这些部件不仅要求为其供电的高压电源稳定度高,而且要求在它们发生打火现象时,保护时间短(<10μs),高压电源对其释放的能量小,否则这些关键部件极易受到损坏。基于脉冲步进调制PSM技术的高压脉冲电源是许多相同的脉冲电源串联并经过特定的调制方式控制,从而实现高压大功率输出。该高压电源有控制方式灵活、输出功率高、功率因数高、稳定度高、响应速度快、保护时间短、故障时系统对负载的释能小等众多优点。尤其保护时该电源系统储能小,时间短,满足各种高功率微波管和加速器的要求。本文分析了基于主回路的三种控制方式,并选取了PSM技术作为最终控制方式。在此基础上,设计并研制了一套基于PSM技术的高压脉冲电源,实验及运行结果表明该高压电源的线路简洁,控制方式灵活,且各项参数均优于现有基于晶闸管器件的高压电源,最高输出参数约为72kV/90A,能够满足辅助加热系统的要求。     

A Wireless Capsule Endoscope System With Low-Power Controlling and Processing ASIC

This paper presents the design of a wireless capsule endoscope system. The proposed system is mainly composed of a CMOS image sensor, a RF transceiver and a low-power controlling and processing application specific integrated circuit (ASIC). Several design challenges involving system power reduction, system miniaturization and wireless wake-up method are resolved by employing optimized system architecture, integration of an area and power efficient image compression module, a power management unit (PMU) and a novel wireless wake-up subsystem with zero standby current in the ASIC design. The ASIC has been fabricated in 0.18-mum CMOS technology with a die area of 3.4 mm _* 3.3 mm. The digital baseband can work under a power supply down to 0.95 V with a power dissipation of 1.3 mW. The prototype capsule based on the ASIC and a data recorder has been developed. Test result shows that proposed system architecture with local image compression lead to an average of 45% energy reduction for transmitting an image frame.