RF MEMS Oscillator with Integrated Resistive Transduction

A method to integrate micromechanical frequency-determining elements along with the corresponding electromechanical transducers into a poly or single-crystal silicon film layer is demonstrated. A resistor dissipating several microwatt of power induces high-frequency resonant mechanical motion in a shallow-shell membrane. Transduction from the mechanical to the electrical domain is performed using implanted piezoresistors, which are sensitive to strain produced by resonant motion. Self-sustained oscillations at 10 MHz are demonstrated when the device is directly coupled to a high-impedance operational amplifier and a positive feedback loop. Finally, this letter discuss how the resonator and transducers may be incorporated into standard integrated-circuit technology.     

微波微电子机械开关

介绍了微波微电子机械开关(MEMS开关)的形式、物理特性,分析了其工作原理.文中采用一端固定、一端自由运动的悬臂梁的力学模型,给出了MEMS开关设计的经验公式.最后,对微电子机械开关在MMIC中的发展前景作出了预测.     

Micro MEMS

RF Micro Devices Inc has shipped its 250m power amplifier (PA) module.This is a short news story only. Visit www.three-fives.com for the latest advanced semiconductor industry news.     

MEMS switches

Microelectromechanical system (MEMS) microswitches are receiving increasing attention, particularly in the RF community. Low power consumption, low insertion loss, high isolation, excellent linearity, and the ability to be integrated with other electronics all make microswitches an attractive alternative to other mechanical and solid-state switches. This article features a newly developed, surface micromachined, electrostatically actuated direct metal-to-metal microswitch which can be used in applications from dc through microwave.     

RF MEMS phase shifters based on PCB MEMS technology

An X-band main-line type loaded line RF MEMS phase shifter fabricated using printed circuit based MEMS technology is reported. The phase shifter provides a phase shift of 31.6/spl deg/ with a minimum insertion loss of 0.56 dB at 9 GHz for an applied DC bias voltage of 40 V. These phase shifters are suitable for monolithic integration with low-cost phased arrays on Teflon or Polyimide such as low dielectric constant substrates.     

Tunable MEMS LC resonator with large tuning range

A tunable resonator based on MEMS technology is reported. The resonator is a parallel LC type resonator, in which the capacitor is made up of two metal bridges and the inductor is made up of a shorted stub. The length of the shorted stub is changed by shunt DC contact switches and therefore inductance values of the resonator can be varied. As a result, the resonant frequency of the resonator can be shifted from 8 to 14 GHz with 75% tunable range. The whole size of the resonator is 6/spl times/0.9 mm/sup 2/.     

电阻悬浮的MEMS热膜式气体流量传感器设计

设计了一种新型电阻悬浮结构的热膜式气体流量传感器,具有测量精度高、灵敏度好、抗压能力强、微加工工艺简单等特点。采用ANSYS软件对传感器芯片在不同流速下的温度场进行了有限元仿真,得出了上下游温差与流速的关系曲线。通过比较热膜电阻非悬浮与悬浮时的导热损失和压力分布,得到了将热膜电阻悬浮的流量传感器的性能要优于一般传感器的结论,其灵敏度为一般传感器的3.6倍。分析表明,传感器的响应时间仅为0.17 ms,比一般传感器快了好几倍;流速在0～0.5 m/s和0.5～2.5 m/s时,传感器输出信号都有较好的线性度,使其能够应用于小流量和大流量的测量当中;流道高度为150μm时,流量为0～2.7 L/h。根据工艺条件和仿真结果,确定了传感器芯片的结构尺寸和微加工工艺流程。     

采用MEMS工艺的表面贴装麦克风有望取代ECM

传统的电容式麦克风(ECM)一直在便携式应用中占据统治地位,但是这样的局面已经被打破,美国楼氏电子(Knowles Acoustics)推出据称全球首款表面贴装SiSonic微型麦克风,其中的麦克风部件采用半导体MEM S技术制造,并将其与一个COMS电荷泵IC、两个RF滤波电容集成在一个封装中组成一个表面贴装器件.     

MEMS的前景

微机电系统(MEMS)在研究领域已经有很长历史了,但一直没有真正进入大规模产业化阶段.而现在将硅芯片和微机械结构结合在一起的光学元件为MEMS带来新的商业机会.MEMS热了起来,各种新起步的MEMS公司开始吸引大量的风险资金.一些在此领域已经发展了数年的公司宣称自己开始得到回报,甚至已经赢利.但业内人士认为MEMS元件仅仅是刚开始从实验室走向实用,对许多半导体公司来说,MEMS业务最终能否取得成功的关键在于他们如何充分利用在IC方面获得的设计、制造和市场经验.     

世界MEMS预测

<正> 据《Semiconductor World》通卷263号载文报道,Cahners in-stat Group 预测出今后的MEMS 市场扩大趋势。据该公司预测,世界的 MEMS 市场必将由2000年的约30亿美元逐年向上增加,至2005年预计可达到120亿美元。对于传感器来说,2000年的销售额虽然很大,但至2005年,必然会让位给传动装置,     

MEMS in space

The satellite industry could experience its biggest revolution since it joined the ranks of commerce, thanks to some of the smallest machines in existence. Researchers are performing experiments designed to convince the aerospace industry that microelectromechanical systems (MEMS) could open the door to low-cost, high-reliability, mass-produced satellites. MEMS combine conventional semiconductor electronics with beams, gears, levers, switches, accelerometers, diaphragms, microfluidic thrusters, and heat controllers, all of them microscopic in size. Some of the advantages of using MEMS-based satellites are low launch costs and high resistance to radiation and vibration. MEMS-based satellites also promise to be cheaper to develop and fabricate than conventional spacecraft     

正从实验室走出的MEMS

微机电系统(MEMS : MicroElectro-Mechanical System)是一种集成微传感器、微执行器、信号处理和控制电路、通信接口和电源等部件,实现感应和控制物理环境的芯片级设备。MEMS在经过25年的发展后,目前正在走出实验室,逐渐成为一个新兴的工业领域。MEMS的应用范围正在不断扩大,从汽车气囊到打印机、电信设备等,这个芯片级设备的出现,正在促使产品真正迈向低成本、高性能。虽然MEMS技术所具有的优点是无可置疑的,然而将这些先进的技术思想转换成新产品的开发进程却还是太慢了。其原因之一是设备本身的多样性和复杂性:对于MEMS的组装,…     

Microfluidics meets MEMS

The use of planar fluidic devices for performing small-volume chemistry was first proposed by analytical chemists, who coined the term "miniaturized total chemical analysis systems" (/spl mu/TAS) for this concept. More recently, the /spl mu/TAS field has begun to encompass other areas of chemistry and biology. To reflect this expanded scope, the broader terms "microfluidics" and "lab-on-a-chip" are now often used in addition to /spl mu/TAS. Most microfluidics researchers rely on micromachining technologies at least to some extent to produce microflow systems based on interconnected micrometer-dimensioned channels. As members of the microelectromechanical systems (MEMS) community know, however, one can do more with these techniques. It is possible to impart higher levels of functionality by making features in different materials and at different levels within a microfluidic device. Increasingly, researchers have considered how to integrate electrical or electrochemical function into chips for purposes as diverse as heating, temperature sensing, electrochemical detection, and pumping. MEMS processes applied to new materials have also resulted in new approaches for fabrication of microchannels. This review paper explores these and other developments that have emerged from the increasing interaction between the MEMS and microfluidics worlds.     

MEMS optical switches

Leveraging MEMS's inherent advantages such as the batch fabrication technique, small size, integrability, and scalability, MEMS is positioned to become the dominant technology in optical crossconnect switches. MEMS optical switches with complex movable 3D mechanical structures, micro-actuators, and micro-optics can be monolithically integrated on the same substrate by using the matured fabrication process of the integrated circuit industry. In this article we report various popular actuating mechanisms and switch architectures of MEMS optical switches. The basics of surface and bulk micromachining techniques used to fabricate MEMS devices are reviewed. Examples of 2D and 3D approaches to MEMS optical switches are described. The pros and cons of the two approaches are analyzed. In the short term, MEMS-based optical switches seem to have captivated the attention of both the industry and academia. However, there are challenges that threaten the long-term survival of this technology. The problems that remain to be fully addressed are discussed