Design and modeling of a continuously variable piezoelectric RF MEMS switch (original) (raw)
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Contactless RF MEMS switch using PZT actuation
The 8th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 2013
order to achieve higher data rate or resolution in a miniaturized system with low power consumption, there is continued pressure to develop and improve small, high performance devices for manipulating rF signals at microwave, centrimetric and millimeter wave frequencies.
A stiff and flat membrane operated DC contact type RF MEMS switch with low actuation voltage
Sensors and Actuators A: Physical, 2009
RF MEMS switches can be divided into electrostatic, magnetic, thermal, and piezoelectric types by their actuation mechanisms. Most research has focused on the electrostatic actuation types because of these types low power consumption, simple fabrication method, and good RF characteristics. However, these types of switches operate at high voltages compared with the other types. One of the main problems that affect the operation voltages is the bending of the membrane due to an internal stress gradient. To solve this problem, a thick and stiff membrane operated RF MEMS switch has been developed and is presented in this paper. This membrane consists of a flexible spring for an up-down actuation mode at low voltage and a pivot under the membrane for a seesaw mode on-off switch operation. This novel RF MEMS switch has been fabricated, and its RF characteristics measured. The minimum actuation voltage is approximately 10-12 V, the isolation approximately −50 dB, and the insertion loss is approximately −0.25 dB at 2 GHz, respectively.The bending range of the membrane has been measured by using an optical 3D profiler and the height is within 0.2 m across the 800 m length membrane. This bending range is uniform across all samples of an entire 4 in. wafer.
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.
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.
A New Electrostatically Actuated Low Voltage RF Mems Switch
European Scientific Journal, 2013
This paper describes the design and simulation of a new low voltage electrostatically actuated RF MEMS switch. The switch structure is designed in such a way that, the inherent limitation of electrostatic actuation is relaxed and the actuation voltage is as low as 3.5 V. The idea is to using a two-step electrostatic actuation mechanism instead of conventional two parallel plate electrostatic actuators. In fact the gap between switch and transmission line is reduced in two steps. In order to investigate the usefulness of the proposed idea, both mechanically and electromagnetically, FEM simulations are carried out and satisfactory results are obtained. The RF characteristics of the switch are as follow; Isolation -12 dB at 30 GHz, Insertion Loss -0.08dB at 30 GHz and return loss was below -20 dB at 30 GHz. The proposed switch in this paper can be a promising choice for low voltage high performance RF MEMS switches.
In a MEMS based RF switch Cantilever beam is an element that is fixed at one end and free from another side. The electrostatic actuation process occurs on the beam and it will deflect from an original position. As the Electrostatic force increases, the z-component displacement produced in the beam is also increases. The beam is placed at the 2µm height from the ground substrate. The cantilever works as a switch which operates as ON or OFF. When the switch is ON its capacitance increases and when it is OFF its capacitance decreases. When applied actuation voltage reaches to Pull-in-voltage the cantilever connects with the ground electrode. This paper explores the concept of increase in flexibility, switching speed, low power consumption, low actuation voltage and reduction in squeeze film damping. The various types of cantilever switch provide discrete displacement corresponding to actuation voltage. In this paper we simulated the cantilever switch with various shapes. The simulation is done using COMSOL MULTIPHYSICS software.
Design of low actuation voltage RF MEMS switch
2000
Low-loss microwave microelectromechanical systems (MEMS) shunt switches are reported that utilize highly compliant serpentine spring folded suspensions together with large area capacitive actuators to achieve low actuation voltages while maintaining sufficient off-state isolation. The RF MEMS switches were fabricated via a surface micromachining process using P12545 polyimide as the sacrificial layer. The switch structure was composed of electroplated nickel and the serpentine folded suspensions had a varying number of meanders from 1 to 5. DC measurements indicate actuation voltages as low as 9 V with an on-to-off capacitance ratio of 48. Power handling measurement results showed no "self-biasing" or failure of the MEMS switches for power levels up to 6.6 W. RF measurements demonstrate an isolation of -26 dB at 40 GHz.
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.
Low-loss RF MEMS fixed free capacitive switch characterization
IEEE Applied Electromagnetics Conference, 2009
RF MEMS are small mechanical devices fabricated by photolithographic processes, which are used for elemental signal processing functions in RF and microwave, frequency circuits. The design of low loss RF MEMS fixed free capacitive switch is explained. The most common RF MEMS control component is a microwave transmission line switch, currently under development for applications requiring low insertion loss, high linearity, moderate switching speeds and low to moderate power. These shunt switches possess a movable metal membrane which pulls down onto a metal dielectric sandwich to form a capacitive switch. These switches exhibit low loss (<0.25 dB at 35 GHz) with good isolation (35 dB at 35 GHz).This paper gives the construction and performance of low loss RF MEMS Fixed Free switches at microwave and millimetre-wave frequencies (0.1 to 100 Ghz) and also describes the improvements in the design of the switch.
RF MEMS switches for smart antennas
Microsystem Technologies, 2014
hence, rF MeMS featuring small size, low weight and high performance can be considered as a future enabling technology to replace off-chip passive elements (Girbau et al. 2006).