Microelectromechanical Systems (MEMS) stand poised for the next major breakthrough in the silicon revolution that began with the transistor in the 1960s and has revolutionized microelectronics. MEMS allow one to not only observe and process information of all types from small scale systems, but also to affect changes in systems and the environment at that scale. “RF MEMS Switches and Integrated Switching Circuits” builds on the extensive body of literature that exists in research papers on analytical and numerical modeling and design based on RF MEMS switches and micromachined switching circuits, and presents a unified framework of coverage. This volume includes, but is not limited to, RF MEMS approaches, developments from RF MEMS switches to RF switching circuits, and MEMS switch components in circuit systems. This book also: -Presents RF Switches and switching circuit MEMS devices in a unified framework covering all aspects of engineering innovation, design, modeling, fabrication, control and experimental implementation -Discusses RF switch devices in detail, with both system and component-level circuit integration using micro- and nano-fabrication techniques -Includes an emphasis on design innovation and experimental relevance rather than basic electromagnetic theory and device physics “RF MEMS Switches and Integrated Switching Circuits” is perfect for engineers, researchers and students working in the fields of MEMS, circuits and systems and RFs.

Micro-Electro-Mechanical (MEM) devices like switches, varactors and oscillators have shown great potential for use in communication devices, sensors and actuators. Electrostatically actuated switches in particular have been shown to have superior performance characteristics over traditional semiconductor switches. However, their widespread insertion in integrated electronics is critically dependent on a thorough understanding of two broad issues - manufacturing process variations and failure mechanisms. Variations during fabrication lead to uncertain material and/or geometric parameters causing a significant impact on device performance. Such uncertainties need to be accounted for during the robust design of these switches. In terms of failure mechanisms limiting the lifetime of MEMS switches, dielectric charging is considered to be the most critical. It can cause the switch to either remain stuck after removal of the actuation voltage or to fail to contact under application of voltage. There is a need for accurate and computationally efficient, multi-physics CAD tools for incorporating the effect of dielectric charging. In this work, we have attempted to address some of the aforementioned challenges. We have come up with new algorithms for improving the effciency of coupled electro-mechanical simulations done in existing commercially available software like ANSYS. The gains in efficiency are accomplished through eliminating the need for repeated mesh update or re-meshing during finite element electrostatic modeling. This is achieved through the development of a `map' between the deformed and un-deformed geometries. Thus only one finite element discretization on the original undeformed geometry is needed for performing electrostatic analysis on all subsequent deformed geometries. We have generalized this concept of `mapping' to perform stochastic electrostatic analysis in the presence of geometric uncertainties. The different random realizations of geometry are considered as deformed geometries. The electrostatic problem on each of these random samples is then obtained using the `mapping' and the finite element simulation on the mean geometry. Statistics such as the mean and standard deviation of the desired system response such as capacitance and vertical force are efficiently computed. This approach has been shown to be orders of magnitude faster than standard Monte Carlo approaches. Next, we have developed a methodology for the model order reduction of MEMS devices under random input conditions to facilitate fast time and frequency domain analyses. In this approach, the system matrices are represented in terms of polynomial expansions of input random variables. The coefficients of these polynomials are obtained by deterministic model order reduction for specific values of the input random variables. These values are chosen `smartly' using a Smolyak algorithm. The stochastic reduced order model is cast in the form of an augmented, deterministic system. The proposed method provides significant efficiency over standard Monte Carlo. Finally, we have developed a physics based, one dimensional macroscopic model for the quantitative description of the process of dielectric charging. The fidelity of the model relies upon the utilization of experimentally-obtained data to assign values to model parameters that capture the non-linear behavior of the dielectric charging process. The proposed model can be easily cast in the form of a simple SPICE circuit. Its compact, physics-based form enables its seamless insertion in non-linear, SPICE-like, circuit simulators and makes it compatible with system-level MEMS computer-aided analysis and design tools. The model enables the efficient simulation of dielectric charging under different, complex control voltage waveforms. In addition, it provides the means for expedient simulation of the impact of dielectric charging on switch performance degradation. It is used to demonstrate failure of a switch in Architect. We conclude with a description of how this one dimensional model can be combined in a detailed two dimensional coupled electro-mechanical framework.

Closes the gap between hardcore-theoretical and purely experimental RF-MEMS books. The book covers, from a practical viewpoint, the most critical steps that have to be taken in order to develop novel RF-MEMS device concepts. Prototypical RF-MEMS devices, both including lumped components and complex networks, are presented at the beginning of the book as reference examples, and these are then discussed from different perspectives with regard to design, simulation, packaging, testing, and post-fabrication modeling. Theoretical concepts are introduced when necessary to complement the practical hints given for all RF-MEMS development stages. Provides researchers and engineers with invaluable practical hints on how to develop novel RF-MEMS device concepts Covers all critical steps, dealing with design, simulation, optimization, characterization and fabrication of MEMS for radio-frequency applications Addresses frequently disregarded issues, explicitly treating the hard to predict interplay between the three-dimensional device structure and its electromagnetic functionality Bridges theory and experiment, fundamental concepts are introduced with the application in mind, and simulation results are validated against experimental results Appeals to the practice-oriented R&D reader: design and simulation examples are based on widely known software packages such as ANSYS and the hardware description language Verilog.

"This work presents a novel approach to modeling and control of an RF- MEMS switch. The model presented in this work is comprehensive and generic in nature such that it takes into account the effect of squeeze film damping, impact force and electrostatic force effects on the dynamic behavior of the switch during pull-in and release of its membrane. This model makes it adaptable to any similar switch regardless of the form and/or dimensions. Simulation results of the switch dynamics is validated against experimental data for an identical switch. Model response to electrostatic voltage shows very good agreement with experiments. The proposed model is then used to construct a feedback controller capable of improving response parameters of the membrane during operation. Due to micro-dimensions of the switch, real time displacement measurement of the membrane is not readily available. Therefore, the proposed controller utilizes measurement of switch capacitors current as a platform for real time estimates of the membrane position. Membrane Current measurement was not available for control purposes due to the lack of the fabricated RF MEMS switch. Consequently, approximate model for current-displacement relationship is constructed from numerical solution of the nonlinear model data and system identification techniques using Simulink."--Abstract.

Ultrasmall Radio Frequency and Micro-wave Microelectromechanical systems (RF MEMs), such as switches, varactors, and phase shifters, exhibit nearly zero power consumption or loss. For this reason, they are being developed intensively by corporations worldwide for use in telecommunications equipment. This book acquaints readers with the basics of RF MEMs and describes how to design practical circuits and devices with them. The author, an acknowledged expert in the field, presents a range of real-world applications and shares many valuable tricks of the trade.