Design of low actuation voltage RF MEMS switch (original) (raw)
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Design of H-shaped low actuation-voltage RF-MEMS switches
2006 Asia-Pacific Microwave Conference, 2006
Low actuation-voltage and high reliable microelectromechanical systems (MEMS) shunt capacitive and shunt resistive switches are in this paper proposed. Electrostatic-mechanical coupling using finite element method (FEM) and full-wave electromagnetic (EM) analyses have been performed. The mechanical design of a low spring-constant switch structure has been optimized by calculating the dependence of the actuation voltage on the membrane shape, material properties and geometrical sizes. The proposed switches, based on Al metallization membrane, show a pull-in voltage around 7 and 13 Volts with 0 and 20 MPa residual stresses, respectively. The simulated insertion losses are less than 0.25 dB up to 40GHz with a return loss of about 20 dB in the ONstate. The isolations in the OFF-state for the capacitive-switch are greater than 20 and 35 dB at 12 and 40 GHz, respectively. The shunt resistive switch theoretically works from zero frequency with isolation greater than 25 dB up to 40 GHz. The fabrication of those switches is compatible with standard CMOS technology and they are in process. Index Terms -Low-actuation voltage, MEMS, Pull-in, RF MEMS switch.
Low Voltage Rf Mems Capacitive Shunt Switches
Micro-electro-mechanical-systems(MEMS) switches have low resistive loss, negligible power consumption, good isolation and high power handling capability compared with semiconductor switches. Lifetime of capacitive shunt switches strongly depends on the actuation voltage so low voltage switches is necessary to enhance its performance as well as to broaden its application area. This paper presents the design and simulation of low voltage capacitive shunt MEMS switches together with its RF performance for high frequency applications. The low voltage switches are realized by lowering the spring constant of the beam using serpentine spring designs together with large capacitive area so as to achieve the good RF performance as well. The pull-in voltage is analyzed with commercial CAD finite element analysis software CoventorWare. The electromagnetic performance in terms of scattering parameters, insertion loss, and isolation are analyzed with software Ansoft HFSS10. The switches achieved insertion loss <0.47 dB in on state from 2 to 40 GHz; it provided better than 25 dB isolation in off state with a capacitance ratio of 94-96. The actuation voltage as low as 1.5 V with actuation area 110 × 100 µm 2 along with good RF performance is reported. The design parameter optimization including selection of appropriate number of meanders and its width found to be one of the most sensitive factors affecting the spring stiffness and actuation voltage.
IEEE Transactions on Microwave Theory and Techniques, 2005
This paper reports new RF microelectromechanical systems (MEMS) switches actuated by the combination of electromagnetic and electrostatic forces for low-voltage and low-power operation. The proposed RF MEMS switches have utilized the proper combination of two actuation mechanisms: taking advantage of the large actuation force from electromagnetic actuation for initial movement and the low-power feature from electrostatic actuation for holding the actuator position. Both series-and shunt-type switches have been implemented using the proposed actuation mechanism. From the fabricated switches, feasibility of operation has been successfully demonstrated. The fabricated switches can be operated within several hundred microseconds. In the series-type switch, the isolation has been measured as 34 dB and insertion loss as 0.37 dB at 20 GHz. In the shunt type switch, the isolation is 20.7 dB and insertion loss is 0.85 dB at 19.5 GHz. The proposed RF MEMS switches are mechanically robust and the combination of electromagnetic and electrostatic actuations makes it possible to achieve excellent switching characteristics at low power and low voltage below 5 V.
Electromechanical considerations in developing low-voltage RF MEMS switches
IEEE Transactions on Microwave Theory and Techniques, 2003
This paper reports on the design, fabrication, and testing of a low-actuation voltage Microelectromechanical systems (MEMS) switch for high-frequency applications. The mechanical design of low spring-constant folded-suspension beams is presented first, and switches using these beams are demonstrated with measured actuation voltages of as low as 6 V. Furthermore, common nonidealities such as residual in-plane and gradient stress, as well as down-state stiction problems are addressed, and possible solutions are discussed. Finally, both experimental and theoretical data for the dynamic behavior of these devices are presented. The results of this paper clearly underline the need of an integrated design approach for the development of ultra low-voltage RF MEMS switches.
Design and optimization of a low-voltage shunt capacitive RF-MEMS switch
2014 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS (DTIP), 2014
This paper presents the design, optimization and simulation of a radio frequency (RF) micro-electromechanical system (MEMS) switch. The device is a capacitive shuntconnection switch, which uses four folded beams to support a big membrane above the signal transmission line. Another four straight beams provide the bias voltage. The switch is designed in 0.35µm complementary metal oxide semiconductor (CMOS) process and is electrostatically actuated by a low pull-in voltage of 2.9V. Taguchi Method is employed to optimize the geometric parameters of the beams, in order to obtain a low spring constant and a robust design. The pull-in voltage, vertical displacement, and maximum von Mises stress distribution was simulated using finite element modeling (FEM) simulation-IntelliSuite v8.7 ® software. With Pareto ANOVA technique, the percentage contribution of each geometric parameter to the spring constant and stress distribution was calculated; and then the optimized parameters were got as t=0.877µm, w=4µm, L1=40µm, L2=50µm and L3=70µm. RF performance of the switch was simulated by AWR Design Environment 10 ® and yielded isolation and insertion loss of-23dB and-9.2dB respectively at 55GHz.
HELIX
The electromagnetic and the electromechanical characteristics of the radio frequency micro-electro-mechanicalsystem (RF MEMS) switches for high-frequency applications are the critical performance metrics that need to optimize. Performance indices of the RF MEMS switches such as isolation, insertion loss, pull-in voltage, holddown voltage, reliability are dependent on types and properties of conducting and insulating materials that are used in the construction of switch. This article proposes the design and analysis of the two terminal capacitive shunt switches built on a coplanar waveguide (CPW) for applications in subsets of Ka-and V-Band frequency range. The proposed switch used a fixed-fixed gold membrane with the low-spring constant uniform single meander flexures support and achieved a low pull-in voltage of 5.1 Volts. An impact of the variation of the geometric parameter trade-offs like conducting membrane height, dielectric material height, and the air gap between the membrane and the dielectric materials like Silicon Nitride (Si3N4) and Hafnium Dioxide (HfO2) are studied to investigate RF and electromechanical performance of the switch.
IAETSD-Design and Analysis of a Novel Low Actuated Voltage RF MEMS Shunt Capacitive Switch
This Paper presents design, analysis, proposed fabrication process and simulation of a novel low actuated voltage shunt capacitive RF MEMS Switch. The Air gap in between the membrane and CPW signal line is 1.5 µm. The lowest actuation voltage of switch is 3 Volts. The proposed fixedfixed flexures beam structure provides excellent RF Characteristics (Isolation -43 dB at 28 GHZ and insertion loss -0.12 dB at 28 GHZ).
Design of RF MEMS Switch with High Stability Effect at the Low Actuation Voltage
Sensors & Transducers, 2009
MEMS switches are one of the most promising future micro-machined products that have attracted numerous research efforts in recent years. This paper presents an innovative design of RF MEMS switch, with low actuation voltage (VT), improved mechanical stability and reduced stiction. The proposed switch is fabricated on a coplanar waveguide (CPW) & actuated by electrostatic force. The mechanical and electrical performance of the switch has been tested. The simulation results show that the actuation voltage can be reduced by using serpentine folded spring, and improved mechanical stability and reduced stiction can be achieved by using a hydrophobic material with high Young's modulus as insulator in between top and bottom electrode. The measured pull-in voltage is 4 V.
Mechanical Design of RF MEMS Capacitive Switches
2000
This paper analyses the mechanical behaviour of various suspensions of electrostatically actuated RF MEMS switches. A family of capacitive switches is described, with suspensions varying step by step from cantilevers to meander shaped double clamped beams. The result is a capacitive shunt switch with a designed actuation voltage of 4.5 V, and 20dB isolation and 0.04 dB insertion loss at a frequency of 2 GHz. At the time of writing, the proposed devices are being processed.
Journal of Micro/Nanolithography, MEMS, and MOEMS, 2015
A new cantilever type radio frequency microelectromechanical systems (RF MEMS) shunt capacitive switch design and fabrication is presented. The mechanical, electromechanical, and electromagnetic designs are carried out to get <40 V actuation voltage, high isolation, and low insertion loss for 24 and 35 GHz and the fabrication is carried out for 24 GHz RF MEMS switch. The fabricated switch shows lower than 0.35 dB insertion loss up to 40 GHz and greater than 20 dB isolation at 22 to 29 GHz frequency band. An insignificant change is observed on RF performance at 24 GHz (ΔS 11 ¼ 1 dB, ΔS 21 < 0.1 dB) after 200°C thermal treatment for 30 min. The switch is fabricated on quartz wafer using an in-house surface micromachining process with amorphous silicon sacrificial layer structure. Total MEMS bridge thickness is aimed to be 4 μm and consists of 2-μm-thick sputtered and 2-μm-thick electroplated gold layers. The bridge bending models and pull-down voltage simulations are carried out for different stress levels and equivalent Young's modulus (E avg).