Robust Design of RF-MEMS Cantilever Switches Using Contact Physics Modeling

This paper presents the robust design optimization of an RF-MEMS direct contact cantilever switch for minimum actuation voltage and opening time, and maximum power handling capability. The design variables are the length and thickness of the entire cantilever, the widths of the sections of the cantilever, and the dimple size. The actuation voltage is obtained using a 3-D structural-electrostatic finite-element method (FEM) model, and the opening time is obtained using the same FEM model and the experimental model of adhesion at the contact surfaces developed in our previous work. The model accounts for an unpredictable variance in the contact resistance resulting from the micromachining process for the estimation of the power handling. This is achieved by taking the ratio of the root mean square power of the RF current (signal") passing through the switch to the contact temperature ("noise") resulting from the possible range of the contact resistance. The resulting robust optimization problem is solved using a Strength Pareto Evolutionary Algorithm, to obtain design alternatives exhibiting different tradeoffs among the three objectives. The results show that there exists substantial room for improved designs of RF-MEMS direct-contact switches. It also provides a better understanding of the key factors contributing to the performances of RF-MEMS switches. Most importantly, it provides guidance for further improvements of RF-MEMS switches that exploit complex multiphysics phenomena.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87274/4/Saitou7.pd

Design considerations of a MEMS cantilever beam switch for pull-in under electrostatic force generated by means of vibrations

This study is about investigation of design considerations of a MEMS switch that is considered to pull in under electrostatic force generated by a piezoelectric based voltage generator inside the MEMS. Here the energy source to drive the piezoelectric device is vibrations the whole system undergoes. In this study, a new approach is brought to calculate the pull-in voltage easily and effectively under certain assumptions. There are a number of conditions the switch has to meet such as its robustness against environmental vibrations. Some are discussed in brief. Following the design considerations a series of MEMS switches are fabricated and the pull-in voltages are measured in order to compare the true data with calculations and simulations. Numerical results prove the validity of the new approach to calculate the pull-in voltage, and experimental results coincide greatly with the calculations. Several materials are investigated to be used in the design of the cantilever beam and finally a beam structure is proposed that fits best for overall specifications

Design considerations of a MEMS cantilever beam switch for pull-in under electrostatic force generated by means of vibrations

This study is about investigation of design considerations of a MEMS switch that is considered to pull in under electrostatic force generated by a piezoelectric based voltage generator inside the MEMS. Here the energy source to drive the piezoelectric device is vibrations the whole system undergoes. In this study, a new approach is brought to calculate the pull-in voltage easily and effectively under certain assumptions. There are a number of conditions the switch has to meet such as its robustness against environmental vibrations. Some are discussed in brief. Following the design considerations a series of MEMS switches are fabricated and the pull-in voltages are measured in order to compare the true data with calculations and simulations. Numerical results prove the validity of the new approach to calculate the pull-in voltage, and experimental results coincide greatly with the calculations. Several materials are investigated to be used in the design of the cantilever beam and finally a beam structure is proposed that fits best for overall specifications

Design considerations of a MEMS cantilever beam switch for pull-in under electrostatic force generated by means of vibrations

This study is about investigation of design considerations of a MEMS switch that is considered to pull in under electrostatic force generated by a piezoelectric based voltage generator inside the MEMS. Here the energy source to drive the piezoelectric device is vibrations the whole system undergoes. In this study, a new approach is brought to calculate the pull-in voltage easily and effectively under certain assumptions. There are a number of conditions the switch has to meet such as its robustness against environmental vibrations. Some are discussed in brief. Following the design considerations a series of MEMS switches are fabricated and the pull-in voltages are measured in order to compare the true data with calculations and simulations. Numerical results prove the validity of the new approach to calculate the pull-in voltage, and experimental results coincide greatly with the calculations. Several materials are investigated to be used in the design of the cantilever beam and finally a beam structure is proposed that fits best for overall specifications

RF-MEMS for high-performance and widely reconfigurable passive components – A review with focus on future telecommunications, Internet of Things (IoT) and 5G applications

Abstract Since its first discussions in literature during late '90s, RF-MEMS technology (i.e. Radio Frequency MicroElectroMechanical-Systems) has been showing uncommon potential in the realisation of high-performance and widely reconfigurable RF passives for radio and telecommunication systems. Nevertheless, against the most confident forecasts sparkling around the successful exploitation of RF-MEMS technology in mass-market applications, with the mobile phone segment first in line, already commencing from the earliest years of the 2000s, the first design wins for MEMS-based RF passives have started to be announced just in late 2014. Beyond the disappointment of all the most flattering market forecasts and, on the other hand, the effective employment of RF-MEMS in niche applications (like in very specific space and defence scenarios), there were crucial aspects, not fully considered since the beginning, that impaired the success of such a technology in large-market and consumer applications. Quite unexpectedly, the context has changed rather significantly in recent years. The smartphones market segment started to generate a factual need for highly reconfigurable and high-performance RF passive networks, and this circumstance is increasing the momentum of RF-MEMS technology that was expected to take place more than one decade ago. On a broader landscape, the Internet of Things (IoT) and the even wider paradigm of the Internet of Everything (IoE) seem to be potential fields of exploitation for high-performance and highly reconfigurable passive components in RF-MEMS technology. This work frames the current state of RF-MEMS market exploitation, analysing the main reasons impairing in past years the proper employment of Microsystem technology based RF passive components. Moreover, highlights on further expansion of RF-MEMS solutions in mobile and telecommunication systems will be briefly provided and discussed

Robust Design of RF-MEMS Cantilever Switches Using Contact Physics Modeling

This paper presents the design optimization of a RF MEMS direct contact cantilever switch for minimum actuation voltage and opening time, and maximum power handling capability. The design variables are the length and thickness of the entire cantilever, the widths of the sections of the cantilever, and the dimple size. The actuation voltage is obtained using a 3D structural-electrostatic FEM model, and the opening time is obtained using the same FEM model and the experimental model of adhesion at the contact surfaces developed in our previous work. Since the precise control of the contact resistance during the micro machining process is practically impossible, the power handling capability is estimated as the ratio of the RMS power of the RF current (signal") passing through the switch to the contact temperature ("noise") resulting from the possible range of the contact resistance. The resulting robust optimization problem is solved using a Strength Pareto Evolutionary Algorithm, to obtain design alternatives exhibiting different trade-offs among the three objectives. The results show that there exists substantial room for improved designs of RF MEMS direct-contact switches.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87228/4/Saitou67.pd

Design for reliability applied to RF-MEMS devices and circuits issued from different TRL environments

Ces travaux de thèse visent à aborder la fiabilité des composants RF-MEMS (commutateurs en particulier) pendant la phase de conception en utilisant différents approches de procédés de fabrication. Ça veut dire que l'intérêt est focalisé en comment éliminer ou diminuer pendant la conception les effets des mécanismes de défaillance plus importants au lieu d'étudier la physique des mécanismes. La détection des différents mécanismes de défaillance est analysée en utilisant les performances RF du dispositif et le développement d'un circuit équivalent. Cette nouvelle approche permet à l'utilisateur final savoir comment les performances vont évoluer pendant le cycle de vie. La classification des procédés de fabrication a été faite en utilisant le Technology Readiness Level du procédé qui évalue le niveau de maturité de la technologie. L'analyse de différentes approches de R&D est décrite en mettant l'accent sur les différences entre les niveaux dans la classification TRL. Cette thèse montre quelle est la stratégie optimale pour aborder la fiabilité en démarrant avec un procédé très flexible (LAAS-CNRS comme exemple de baisse TRL), en continuant avec une approche composant (CEA-Leti comme moyenne TRL) et en finissant avec un procédé standard co-intégré CMOS-MEMS (IHP comme haute TRL) dont les modifications sont impossibles.This thesis is intended to deal with reliability of RF-MEMS devices (switches, in particular) from a designer point of view using different fabrication process approaches. This means that the focus will be on how to eliminate or alleviate at the design stage the effects of the most relevant failure mechanisms in each case rather than studying the underlying physics of failure. The detection of the different failure mechanisms are investigated using the RF performance of the device and the developed equivalent circuits. This novel approach allows the end-user to infer the evolution of the device performance versus time going one step further in the Design for Reliability in RF-MEMS. The division of the fabrication process has been done using the Technology Readiness Level of the process. It assesses the maturity of the technology prior to incorporating it into a system or subsystem. An analysis of the different R&D approaches will be presented by highlighting the differences between the different levels in the TRL classification. This thesis pretend to show how reliability can be improved regarding the approach of the fabrication process starting from a very flexible one (LAAS-CNRS as example of low-TRL) passing through a component approach (CEA-Leti as example of medium-TRL) and finishing with a standard co-integrated CMOS-MEMS process (IHP example of high TRL)