Study of a bistable micromechanism for double throw RF switch applications
01 Dec 2015-pp 1-6
TL;DR: In this paper, the authors presented the study of a compliant bistable micromechanism that is proposed to be used in the development of double-throw RF switches, based on its elastic potential energy as a function of the relevant linear displacement coordinate.
Abstract: Bistable micromechanisms form the basis of a large class of latchable MEMS devices. In such systems, external power is required only to switch the system from one stable state to another stable state. This paper presents the study of a bistable micromechanism that is proposed to be used in the development of double throw RF switches. A lumped element equivalent of the compliant bistable micromechanism is analysed based on its elastic potential energy as a function the relevant linear displacement coordinate. Dimensions of a bistable micromechanism compatible with silicon bulk micromachining techniques are arrived at. The bistable actuator has a stroke of 10 µm. The force displacement curve for the system is obtained numerically. The forward and reverse critical driving forces, are 0.04 mN and −0.1 mN respectively. These forces which are within the capability of electrothermal actuation.
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TL;DR: In this paper, a monolithic mechanically bistable mechanism that does not rely on residual stress for its bistability is presented, based on two curved centrally-clamped parallel beams, hereafter referred to as double curved beams.
Abstract: This paper presents a monolithic mechanically-bistable mechanism that does not rely on residual stress for its bistability. The typical implementation of this mechanism is two curved centrally-clamped parallel beams, hereafter referred to as "double curved beams". Modal analysis and finite element analysis (FEA) simulation of the curved beam are used to predict, explain, and design its bistable behavior. Microscale double curved beams are fabricated by deep-reactive ion etching (DRIE) and their test results agree well with the analytic predictions. Approaches to tailor the bistable behavior of the curved beams are also presented.
601 citations
TL;DR: In this article, a comprehensive thermal model for an electro-thermal-compliant (ETC) microactuator is presented, which accounts for all modes of heat dissipation and the temperature dependence of thermophysical and heat transfer properties.
Abstract: A comprehensive thermal model for an electro-thermal-compliant (ETC) microactuator is presented in this paper. The model accounts for all modes of heat dissipation and the temperature dependence of thermophysical and heat transfer properties. The thermal modelling technique underlying the microactuator model is general and can be used for the virtual testing of any ETC device over a wide range of temperatures (300-1500 K). The influence of physical size and thermal boundary conditions at the anchors, where the device is connected to the substrate, on the behaviour of an ETC microactuator is studied by finite element simulations based on the comprehensive thermal model. Simulations show that the performance ratio of the microactuator increased by two orders of magnitude when the characteristic length of the device was increased by one order of magnitude from 0.22 to 2.2 mm. Restricting heat loss to the substrate via the device anchors increased the actuator stroke by 66% and its energy efficiency by 400%, on average, over the temperature range of 300-1500 K. An important observation made is that the size of the device and thermal boundary conditions at the device anchor primarily control the stroke, operating temperature and performance ratio of the microactuator for a given electrical conductivity.
196 citations
TL;DR: In this article, a self-retracting fully compliant bistable mechanism (SRFBM) is proposed, which uses tensural pivots to manage compressive loading in compliant mechanisms.
Abstract: A new class of fully compliant bistable mechanisms with the added benefit of integrated self-retraction has been developed (hereafter identified as Self-Retracting Fully compliant Bistable Mechanism or SRFBM). A technique using tensural pivots to manage compressive loading in compliant mechanisms is introduced and implemented in the SRFBM. The elimination of traditional kinematic joints and their associated clearance allows a total displacement between stable positions of 8.5 /spl mu/m, and the mechanism size is less than 300 /spl mu/m square when using 2.0 /spl mu/m minimum line widths. Maximum actuation force is approximately 500 /spl mu/N. The SRFBM's small linear displacement and reasonable actuation force facilitate integration with efficient thermal actuators. Furthermore, fully compliant mechanisms allow greater freedom in fabrication as only one mechanical layer is needed. Systems with on-chip actuation have been fabricated and tested, demonstrating bistability and on-chip actuation, which requires approximately 150 mW. A single fatigue test has been completed, during which the SRFBM endured approximately 2 million duty cycles without failure.
157 citations
"Study of a bistable micromechanism ..." refers background in this paper
...The working priciple of the mechanism presented here is different from the situation where the whole beam is allowed to deform, thereby distributing its strain energy through out the length of the beam [8], [9], [10]....
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Book•
06 Oct 2006
TL;DR: In this article, the authors present an overview of smart materials and their applications in the context of smart sensors and actuators, as well as some design principles and applications of smart devices.
Abstract: Preface. About the Authors. PART 1: FUNDAMENTALS. 1. Introduction to Smart Systems. 1.1 Components of a smart system. 1.2 Evolution of smart materials and structures. 1.3 Application areas for smart systems. 1.4 Organization of the book. References. 2. Processing of Smart Materials. 2.1 Introduction. 2.2 Semiconductors and their processing. 2.3 Metals and metallization techniques. 2.4 Ceramics. 2.5 Silicon micromachining techniques. 2.6 Polymers and their synthesis. 2.7 UV radiation curing of polymers. 2.8 Deposition techniques for polymer thin films. 2.9 Properties and synthesis of carbon nanotubes. References. PART 2: DESIGN PRINCIPLES. 3. Sensors for Smart Systems. 3.1 Introduction. 3.2 Conductometric sensors. 3.3 Capacitive sensors. 3.4 Piezoelectric sensors. 3.5 Magnetostrictive sensors. 3.6 Piezoresistive sensors. 3.7 Optical sensors. 3.8 Resonant sensors. 3.9 Semiconductor-based sensors. 3.10 Acoustic sensors. 3.11 Polymeric sensors. 3.12 Carbon nanotube sensors. References. 4. Actuators for Smart Systems. 4.1 Introduction. 4.2 Electrostatic transducers. 4.3 Electromagnetic transducers. 4.4 Electrodynamic transducers. 4.5 Piezoelectric transducers. 4.6 Electrostrictive transducers. 4.7 Magnetostrictive transducers. 4.8 Electrothermal actuators. 4.9 Comparison of actuation schemes. References. 5. Design Examples for Sensors and Actuators. 5.1 Introduction. 5.2 Piezoelectric sensors. 5.3 MEMS IDT-based accelerometers. 5.4 Fiber-optic gyroscopes. 5.5 Piezoresistive pressure sensors. 5.6 SAW-based wireless strain sensors. 5.7 SAW-based chemical sensors. 5.8 Microfluidic systems. References. PART 3: MODELING TECHNIQUES. 6. Introductory Concepts in Modeling. 6.1 Introduction to the theory of elasticity. 6.2 Theory of laminated composites. 6.3 Introduction to wave propagation in structures. References. 7. Introduction to the Finite Element Method. 7.1 Introduction. 7.2 Variational principles. 7.3 Energy functionals and variational operator. 7.4 Weak form of the governing differential equation. 7.5 Some basic energy theorems. 7.6 Finite element method. 7.7 Computational aspects in the finite element method. 7.8 Superconvergent finite element formulation. 7.9 Spectral finite element formulation. References. 8. Modeling of Smart Sensors and Actuators. 8.1 Introduction. 8.2 Finite element modeling of a 3-D composite laminate with embedded piezoelectric sensors and actuators. 8.3 Superconvergent smart thin-walled box beam element. 8.4 Modeling of magnetostrictive sensors and actuators. 8.5 Modeling of micro electromechanical systems. 8.6 Modeling of carbon nanotubes (CNTs). References. 9. Active Control Techniques. 9.1 Introduction. 9.2 Mathematical models for control theory. 9.3 Stability of control system. 9.4 Design concepts and methodology. 9.5 Modal order reduction. 9.6 Active control of vibration and waves due to broadband excitation. References. PART 4: FABRICATION METHODS AND APPLICATIONS. 10. Silicon Fabrication Techniques for MEMS. 10.1 Introduction. 10.2 Fabrication processes for silicon MEMS. 10.3 Deposition techniques for thin films in MEMS. 10.4 Bulk micromachining for silicon-based MEMS. 10.5 Silicon surface micromachining. 10.6 Processing by both bulk and surface micromachining. 10.7 LIGA process. References. 11. Polymeric MEMS Fabrication Techniques. 11.1 Introduction. 11.2 Microstereolithography. 11.3 Micromolding of polymeric 3-D structures. 11.4 Incorporation of metals and ceramics by polymeric processes. 11.5 Combined silicon and polymer structures. References. 12. Integration and Packaging of Smart Microsystems. 12.1 Integration of MEMS and microelectronics. 12.2 MEMS packaging. 12.3 Packaging techniques. 12.4 Reliability and key failure mechanisms. 12.5 Issues in packaging of microsystems. References. 13. Fabrication Examples of Smart Microsystems. 13.1 Introduction. 13.2 PVDF transducers. 13.3 SAW accelerometer. 13.4 Chemical and biosensors. 13.5 Polymeric fabrication of a microfluidic system. References. 14. Structural Health Monitoring Applications. 14.1 Introduction. 14.2 Structural health monitoring of composite wing-type structures using magnetostrictive sensors/actuators. 14.3 Assesment of damage severity and health monitoring using PZT sensors/actuators. 14.4 Actuation of DCB specimen under Mode-II dynamic loading. 14.5 Wireless MEMS-IDT microsensors for health monitoring of structures and systems. References. 15. Vibration and Noise-Control Applications. 15.1 Introduction. 15.2 Active vibration control in a thin-walled box beam. 15.3 Active noise control of structure-borne vibration and noise in a helicopter cabin. References. Index.
98 citations
"Study of a bistable micromechanism ..." refers background in this paper
...Commonly used actuation mechanisms are electrostatic, electrothermal, piezoelectric or electromagnetic [2]....
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TL;DR: In this paper, a compliant bistable micromechanism was developed which can be switched in either direction using on-chip thermal actuation using elastic deflection of compliant segments.
Abstract: A compliant bistable micromechanism has been developed which can be switched in either direction using on-chip thermal actuation. The energy storage and bistable behavior of the mechanism is achieved through the elastic deflection of compliant segments. The Pseudo-Rigid-Body Model was used for the compliant mechanism design, and for analysis of the large deflection flexible segments. To achieve on-chip actuation, the mechanism design was optimized to allow it to be switched using linear motion thermal actuators. The modeling theory and analysis are presented for three design iterations, with two iterations fabricated in the MUMP's process and the third in the SUMMiT process.
77 citations