RFMEMS开关及其抗连续波烧毁功率的测试与分析

MEMS开关的功率能力是MEMS开关使用中必须考虑的一个指标,本文测试了我所研制的RFMEMS开关的抗连续波烧毁功率性能,其抗连续波烧毁功率达到35.1dBm。解剖分析了烧毁样品,对功率烧毁机理进行了进一步的讨论。     

Deformation measurement of RF MEMS switches by optical interference

The RF switches were fabricated based on microelectromechanical techniques. For good RF performances, the precise control is needed over the contact separation when switch is open and over the contact force when the switch is closed. In this paper, the optical interference technique has been applied to make the accurate measurement of the contact position and the height distribution of the actuators. The shape changes of switches can be observed in original shape and in actuated state. The results were compared with the scan electronic microscope (SEM) measurement.     

RF MEMS技术

通信收发机、天线等无线设备的发展趋势是高性能、小体积、低成本。微电子机械系统技术在这一趋势中显现了技术潜力。本文阐述了RFMEMS技术的现状。     

RF VCO tuning using MEMS piezoelectric actuated variable inductors

This paper presents a study on the use of microsystems technology in the design of radio frequency voltage-controlled oscillators. In particular, the application of a micro-electro-mechanical systems (MEMS) based variable inductor for frequency tuning purposes is presented. Although traditionally a MEMS variable inductor is considered as a means to extend the tuning range, in this work it is shown that with correct inductor design it is also possible to facilitate and improve the voltage-controlled oscillator design in terms of phase noise response and power consumption in comparison to a design based on standard capacitive tuning.     

射频微电子机械系统的发展与展望

介绍了射频微电子机械系统 ( RF MEMS)的最新进展、研究内容及应用前景。该系统装置包括开关、继电器、电容器、电感器、滤波器及微波和毫米波元件。     

RF MEMS器件面面观

RF-MEMS器件的出现,适应了现代光刻技术和硅IC技术、无线通讯技术的发展的需要,因此很快引起学术界和工业的巨大的重视。可以预言,RF-MEMS器件将很快从实验室走向生产实际,在国民经济的各个方面包括通讯、航天航空技术、交通技术、生物医学领域以及国防工业中发挥重要作用。     

Center-Shift Method for the Characterization of Dielectric Charging in RF MEMS Capacitive Switches

Radio frequency (RF) micro-electro-mechanical systems (MEMS) capacitive switches show great promise for use in wireless communication devices such as mobile phones, but for the successful application of these switches their reliability needs to be demonstrated. One of the main factors that limits the reliability is charge injection in the dielectric layer (SiN) which can cause irreversible stiction of the moving part of the switch.      

RF MEMS的关键技术与器件

文章介绍了RF MEMS的基本概念、基本特征与关键工艺技术。文章在介绍了RF-MEMS 元器件的基础上,对RF MEMS与MMIC进行了比较,分析了RF MEMS需解决的重点问题。最后对 RF MEMS的发展前景进行了展望。     

RF MEMS开关的设计分析

针对具有低损耗、高隔离度性能的微机电系统(Micro-Electro-Mechanical System,MEMS)开关,介绍了串联DC式和并联电容式的开关结构模型,并对并联电容式MEMS开关的工作原理、等效电路模型和制造工艺流程进行了描述,利用其模型研究了开关的微波传输性能,设计了一款电容耦合式开关并进行了仿真。由仿真结果可得,开关"开态"时的插入损耗在40 GHz以内优于-0.3 dB;开关"关态"时的隔离度在20～40 GHz相对较宽的频带内优于-20 dB。     

RF and microwave phase shifter using complementary bias techniques

A novel method for the design of an RF phase shifter using a standard foundry process is described. This phase shift achieves very low and near-constant insertion loss. The proposed method uses `complementary' control techniques to keep variable parasitic resistance in a standard transistor to a minimum. Using an only single stage reflection configuration which employs N varactor diodes as a reflection terminator and M varactor diodes, a minimum insertion loss variation can be obtained. The technique is verified by measurement when N=M=1     

RF MEMS开关的发展现状

RF MEMS开关是其各种组件、系统级应用中最基本的器件之一,具有低损耗、低功耗、线性化好、尺寸小及易集成等特点。对各种开关驱动机制的特点进行了比较,指出具体驱动机制的选取应符合实际应用的需求;在和传统pin开关、FET开关相比较的基础上,总结了RF MEMS开关的优缺点,概述了其目前的应用领域以及面临的主要问题;最后介绍了目前国内外RFMEMS开关研究状况。通过对国内外一些经典RF MEMS开关范例的简述,展望了RFMEMS开关未来的发展趋势。     

软件无线电中RF-MEMS元件

本文分析了软件无线电系统中的MEMS(Micro-Electric-Machine-Systems)解决方案、及其可应用于软件无线电系统中的MEMS器件,主要有对称锥形弯曲缝隙微带天线、用于G波段的微尺度宽频天线、微机械自适应帖片天线、高Q值、双频段MEMS开关、薄膜体声波谐振器、腔结构微机械谐振器、分布式MEMS传输线微机械滤波器等典型的MEMS器件,这些器件克服了普通射频器件体积大,功耗高等缺点,有望在软件无线电系统中得到应用。最后,对MEMS器件在软件无线电系统中的应用做了展望。     

静电式RF MEMS开关的可靠性

MEMS开关是最常见的RF MEMS控制元件,是RF结构中一个关键的MEMS器件。长期可靠性是目前制约MEMS开关商业化进程中的一个主要问题。主要综述了静电式RF MEMS开关可靠性的新进展。欧姆式开关通常由于黏附或接触电阻的增大而失效,电容式开关的主要失效机理则与电介质层的充电有关。接触材料的选择是决定欧姆开关可靠性最重要的一个因素,"主动断开/被动接触"MEMS开关适用于软金属材料欧姆接触的可靠性要求。改善电容式开关可靠性的途径是改善介电层、优化驱动电压波形等以减小介质层的充电。     

射频微机械移相器

MEMS技术显示了其在微波领域的巨大应用潜力.利用RF MEMS开关制造的RF MEMS移相器具有插损小、功耗低、宽带宽、体积小等优点,因此成为研究的热点.本文对国际上RF MEMS的研究和发展进行了比较全面的综述,并介绍了DMTL移相器,该移相器在DC～30GHz范围内具有较好的线性度,在20GHz时相移为0°/11.6°/32.6°/48.5°,反射损失好于-11dB,插损小于-1.8dB.最后分析了各种移相器的特点和设计、制造的难点,对MEMS移相器的发展进行了展望.     

Circulating power, RF magnetic field, and RF current density ofshielded dielectric resonators for power handling analysis ofhigh-temperature superconducting thin films of arbitrary thickness

In the current quest for HTS films with negligible power effects at high RF power levels for wireless communications, accurate calculations of a maximum RF magnetic field H_max and of a maximum RF current density J_max flowing on the surface of superconducting films is necessary to allow for any sensible conclusions and comparisons. As the dielectric resonator method is used most frequently for investigation of HTS losses, the authors discuss in this paper a dependence of the circulating power and of a maximum RF magnetic field H_max on dielectric resonators' geometry as well as of the maximum RF current density J_max flowing on the surface of superconducting films on the films' thickness, for a general case of a resonator shielded in a metallic cavity. The authors' results demonstrate that under the same input power levels the same HTS films may be exposed to differing RF power level conditions, depending on the cavity to dielectric radius ratio and thickness of superconducting films. This means that there may be a significant discrepancy between calculated and real power handling capabilities of HTS films tested in different dielectric resonators unless correct formulas are used     

Self-assembling MEMS variable and fixed RF inductors

Inductors play a key role in wireless front-end circuitry, yet are not generally well suited for conventional RF integrated-circuit (RFIC) fabrication processes. We have developed inductors that can be fabricated on a conventional RFIC silicon substrate, which use warping members to assemble themselves away from the substrate to improve quality factor (Q) and self-resonance frequency (SRF), and to provide a degree of variation in inductance value. These self-assembling variable inductors are realized through foundry provided microelectromechanical systems (MEMS) processing and have demonstrated temperature stable Q values greater than 13, SRF values well above 15 GHz, and inductance variations greater than 18%. Simulations suggest the potential for Q values above 20 and inductance variations greater than 30%, with optimized processing     

一种X频段RF MEMS开关的设计与仿真

设计了一种可用于X频段的射频微机电系统(RF-MEMS)的开关。它通过上电极中心以及两端的螺旋结构提高了等效电感值,减小了谐振频率,从而在较低的频段下实现了较好的隔离度。采用阻抗匹配改善开关结构的射频性能。利用Ansoft HFSS软件仿真分析了开关关键结构参数对电磁性能的影响,包括绝缘介质层厚度k,上电极与下电极之间空气层厚度o、上电极宽度w和上电极间距m,总结了各参数对电磁性能的影响趋势,确定了各参数的最优取值。在整个X频段,开关开态时的插入损耗小于0.83 d B(绝对值,下同);关态时的隔离度大于18.5d B。在中心频率10 GHz的插入损耗为0.57 d B,隔离度为30.65 d B。     

翘板式射频MEMS开关的研究

提出了一种新型的翘板式静电射频微系统开关,给出了理论模拟,结构分析结果和工艺制作方法。该结构采用了5μm厚的无应力单晶硅作为开关的可动部分,可以缓解薄膜应力变形。翘板式结构解决了传统静电设计中动作力弱的问题,并且通过调整支点解决了开关回复力不可调的难题。利用该结构可以在保持高隔离度的同时使驱动电压降低,有限元理论模拟驱动电压为5~10V;采用翘板式结构增加了开关的使用周期,而且结构自身具有单刀双掷特点,可以直接应用于高频通信的频道选择。给出了开关共面波导传输线的测试结果和设计讨论。     

Chip for linearisation of RF power amplifiers using digitalpredistortion

A digital VLSI chip is presented that implements the most critical part of a predistortion system for linearisation of RF power amplifiers. Measurements have shown that the chip provides seven times higher modulation bandwidth (208 kHz) at 10% power (100 mW) compared with a standard digital signal processor