Broadband radio frequency MEMS series contact switch with low insertion loss

A new radio frequency (RF) micro-electro-mechanical-system (MEMS) single cantilever series contact switch is designed as a low-insertion-loss and low-power electronic component that is intended to provide integrated control of the opening and closing signals of other MEMS devices operating over a wide frequency range (DC–60 GHz). The MEMS switching element consists of an A-type top electrode that is fixed onto coplanar waveguide lines through anchor points to reduce the insertion loss in the on-state of the device. The air gap between the top electrode and the actuation electrode of the designed MEMS switch is optimized to improve the isolation characteristics of the switch. In addition, the switching voltage required is approximately 24 V. The simulation results presented here show that the insertion loss of the switch in the on-state is less than 0.71 dB, while the minimum isolation is 20.69 dB in the off-state at 60 GHz. The proposed RF MEMS switch will be useful for communication devices and test instruments used in broadband applications.

     

Design of novel compact anti-stiction and low insertion loss RF MEMS switch

A novel torsional RF MEMS capacitive switch design on silicon substrate is presented. The optimized switch topology such as reduction in up-state capacitance results in insertion loss better than ?0.1 dB till 20 GHz. Off to on state capacitance ratio is also improved by 18 fold and isolation is better than ?43 dB at 9.5 GHz. The achieved on state return loss is ?38 dB as compared to ?21 dB at 9.5 GHz. An optimized reduction in contact area and use of floating metal layer increases the switching speed from 56 to 46 μsec. It also increases the switch reliability by alleviating the stiction.     

A micromachined 2 /spl times/ 2 optical switch aligned with bevel-ended fibers for low return loss

This paper presents the design and optical performance characteristics of a micromachined 2 /spl times/ 2 optical switch with low return loss for an optical add-drop application. The switch is equipped with four optical fibers beveled at 8/spl deg/. An intentional lateral offset was introduced to align the refracted light at the input fiber-air interface with output fibers. A micromirror was actuated into the optical path by an electrostatic comb actuator to change the direction of the input optical signal. The optical switch was fabricated using silicon deep reactive ion etching (DRIE) of silicon-on-insulator (SOI) wafers. Optical performance measurements of the fabricated optical switch revealed that the time dependent loss (TDL), polarization dependent loss (PDL), and wavelength dependent loss (WDL) were -0.04 dB, -0.05 dB and -0.71 dB, respectively. The switching time was within 5 ms for a 24-V electrical step signal. Because the beveled ends of the optical fibers kept the propagated light from reflecting backward into the input fiber, the return losses were just -43 dB. This return loss was used to theoretically analyze a model of the beveled end by considering backscattering due to the surface roughness, which thereby was determined to be about 41 nm.     

Design and investigation of a low insertion loss,broadband, enhanced self and hold down power RF-MEMS switch

This paper presents a low insertion loss capacitive shunt RF-MEMS switch. In the presented design, float metal concept is utilized to reduce the capacitance in up-state of the device. Float metal switch shows an insertion loss <0.11 dB, a return loss below 26.27 dB up to 25 GHz as compared to 0.81 dB insertion, 8.67 dB return loss for the conventional switch without float metal. OFF state response is same for the both devices. Further pull-in voltage of 12.75 V and switching time of 69.62 µs have been observed in case of the conventional switch whereas device with float metal have 11.75 V and 56.41 µs. Improvement of around 2.5 times in bandwidth and 4 times in input power has been observed without self actuation, hold down problem. The designed switch can be useful at device and sub-system level for multi-band applications.     

A low loss and power efficient micro-electro-thermally actuated RF MEMS switch for low power and low loss applications

Microsystem Technologies - A novel laterally and micro-electro-thermally actuated RF MEMS switch is presented in this paper. Despite many RF MEMS switches requiring continuous actuation voltage to...     

Frequency‐selective rasorber with two low insertion loss transmission bands

A frequency‐selective rasorber (FSR) with two low insertion loss transmission bands is proposed. The FSR is composed of the resistive sheet layer at the top and bandpass FSS layer at the bottom, and separated by air spacer. Full‐wave simulation results show that the FSR realize two transmission bands at frequencies 8.5 GHz and 10.8 GHz with 0.45 dB and 0.77 dB insertion loss. Meanwhile, the band with |S₁₁| < ?10 dB is over 4.2‐8.8 GHz and 9.2‐17.4 GHz. Compared with the reported FSR with two transmission bands, the proposed FSR in this article achieves two transmission bands with lower insertion loss and wide absorption band at high frequencies. To validate the performance of the proposed FSR, the samples are fabricated and measured, reasonable agreement between simulated and measured results is achieved.     

High-reliability, high-performance RF micromachined switch using liquid metal

Existing mechanical relays have reliability-related issues including unstable contact resistance and limited cycle life. These problems are caused by mechanical fatigue and wearing of the contact surfaces. In the liquid metal micro switch (LiMMS), we employ a liquid-liquid contact to address these issues. The switching operation is achieved by forming a gap in the liquid metal using gas expansion. Our prototype has a microchannel on a glass substrate to hold a tiny amount of mercury, 0.15 mm in width and 0.1 mm in height, and TaN thin-film heaters on a ceramic substrate to expand the operating gas by heating. The substrates are bonded together and the total size of the device is 5/spl times/5/spl times/1.4 mm. We successfully demonstrated 70-m/spl Omega/ on-resistance, 1 ms-switching speed, the ability to handle up to 1 A of dc current and over 1/spl times/10/sup 8/ cycle operation. LiMMS also has good RF performance, better than 1 dB insertion loss, and better than 20 dB isolation up to 18 GHz.     

一种非接触式微加速度开关的研究

典型的微加速度开关至少包含一个电接触,当阈值加速度值达到时,该开关将闭合。一般为金属接触,比如金。但金属接触可能存在许多问题,如微焊接、电弧、氧化,这些问题可能导致开关工作失灵。鉴于此,本文介绍了一种低驱动电压的非接触式微加速度开关(阈值为5gn)的设计理论、研究方法和主要加工工艺步骤,同时对非接触式微加速度开关结构的力电耦合进行理论计算,结合ANSYS软件仿真分析验证。     

Accurate model for micromachined microwave planar spiral inductors

An accurate model is presented for micromachined on‐chip spiral inductors, in which the high‐frequency current crowding effects in metal traces are considered by simplified partial element equivalent circuits, and the substrate parasitics are extracted by the parametric modeling method. The model has been confirmed by both measurements and the results from the 3‐dimensional finite element method. This equivalent circuit model enables the prediction and optimization of high‐Q micromachined spiral inductors in gigahertz frequencies. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 229–238, 2003.     

Experimental considerations and fabrication analysis of surface micromachined RF NEMS switch

This paper presents fabrication and issues related to fabrication of RF NEMS switch using surface micromachining approach. The switch has been fabricated using electron beam lithography. Lift off process has been used in achieving patterned metal layers. Fabrication process has been optimized by overcoming different issues like proximity effect, field stitching. A high resolution 20 nm gap has been achieved during fabrication. Dose-shape correction method has also been used to achieve desired patterns. A four metal layer fabrication process has been developed for fabrication of RF NEMS switch. Simulation and measured results are also presented.     

Investigation of new micromachined coplanar probe for near-field microwave microscopy

Microsystem Technologies - The near-field measurement is based generally on the use of purely passive miniature sensors, dedicated to the capture of a component of the electromagnetic field. The...     

Stiction-protected MEMS switch with low actuation voltage

Microsystem Technologies - Commercial success of microelectromechanical systems (MEMS) switches is limited by several issues. A high actuation voltage requires special circuitry solutions that...     

Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented.     

一种敏感低加速度的碰撞开关

介绍了一种可以敏感低加速度值的碰撞开关 ,讨论了其理论建模方法及相关内容 ,并从理论、设计和试验方面对冲击响应情况进行了初步分析。该开关的作用门限为 10 0m/s2 ,响应时间为 10ms,可以作为主触发引信应用于某常规武器中 ,其结构和设计方法也可供炮弹、导弹引信用惯性冲击传感器设计人员参考。     

Surix: Non-blocking and low insertion loss micro-ring resonator-based optical router for photonic network on chip

The Journal of Supercomputing - Photonic network-on-chip is utilized as a candidate paradigm for important attributes such as high bandwidth and low energy consumption. In this paper, a...     

Modeling microwave behaviors of series cantilever MEMS switch

Simple and effective model is demanded which enables the design and structural optimization of the microwave MEMS switch efficiently. For this purpose the microwave behaviors of series metal cantilever MEMS switch have been modeled by “simple” circuit in this paper. The microwave characteristics have been calculated and compared with the experiment data based on the developed model. The results show that the microwave characteristics of series metal cantilever MEMS switch can be described very well with this model. Based on this model, the influences of the structural parameters of the switch on the microwave characteristics have been discussed extensively.     

Packet loss analysis of shared-per-wavelength multi-fiber all-optical switch with parallel scheduling

This paper discusses a multi-fiber all-optical switch which shares wavelength converters for contention resolution. The proposed switch architecture employs fixed-input/tunable-output wavelength converters (expected to be less complex than tunable-input/tunable-output ones). The space switching matrix is modular and simple with respect to switching architectures with different wavelength converters sharing schemes (i.e. shared-per-node architecture). A parallel scheduling algorithm is defined to control optical packet forwarding in a synchronous scenario as well as an analytical model to evaluate packet loss performance. The analytical model is validated against simulation and previous analysis and the results obtained show good accuracy in most cases of interest for optical switch design.     

Effective cell loss analysis of a nonblocking ATM switch with nonuniform traffic

This paper quantifies a trade-off existing between cell loss and cell delay in an ATM switch with arbitrary input and output buffer sizes. TheEffective Cell Loss is introduced as a cell loss performance measure which combines both the cell loss due to buffer overflow and the cell loss due to excessive delay. ThisEffective Cell Loss measure allows one to design optimal input and output buffer sizes for a given cell loss requirement. Our analysis is versatile enough to easily study the adverse effect due to nonuniform traffic patterns at a switch. Study shows that the nonuniform traffic may jeopardize ATM switches designed under the uniform traffic assumption. For some examples, we have provided both numerical and computer simulation results to show the validity and usefulness of our analysis.     

Utility-preserving transaction data anonymization with low information loss

Transaction data record various information about individuals, including their purchases and diagnoses, and are increasingly published to support large-scale and low-cost studies in domains such as marketing and medicine. However, the dissemination of transaction data may lead to privacy breaches, as it allows an attacker to link an individual's record to their identity. Approaches that anonymize data by eliminating certain values in an individual's record or by replacing them with more general values have been proposed recently, but they often produce data of limited usefulness. This is because these approaches adopt value transformation strategies that do not guarantee data utility in intended applications and objective measures that may lead to excessive data distortion. In this paper, we propose a novel approach for anonymizing data in a way that satisfies data publishers' utility requirements and incurs low information loss. To achieve this, we introduce an accurate information loss measure and an effective anonymization algorithm that explores a large part of the problem space. An extensive experimental study, using click-stream and medical data, demonstrates that our approach permits many times more accurate query answering than the state-of-the-art methods, while it is comparable to them in terms of efficiency.     

A low voltage vertical comb RF MEMS switch

Design and simulations of a novel RF MEMS switch is reported as a solution to many RF wireless applications. A new comb structure for RF MEMS switch is proposed for low voltage and high frequency operations. Isolation degree and actuation voltage, both improved by the new structure. The mechanical and electromagnetic simulation results show better performance for this new switch compared to parallel plate switch. The simulation is done by the intellisuit and HFSS softwares. The Simulation results show that the actuation voltage is decreased by 13% and the linearity of the switch displacement with respect to the actuation voltage is improved by 22% compared to the parallel plate structure. The HFSS simulation results indicate an insertion loss better than 0.33 dB at 50 GHz and isolation greater than 13.4 dB at 50 GHz.