RF-MEMS switch actuation pulse optimization using Taguchi’s method

Abstract

Reliability and longevity comprise two of the most important concerns when designing Microelectromechanical (MEM) switches. Forcing the switch to perform close to its operating limits underlies a trade-off between response bandwidth and fatigue life due to the impact force of the cantilever touching its corresponding contact point. This paper presents for first time an actuation pulse optimization technique based on Taguchi's optimization method to optimize the shape of the actuation pulse of an ohmic RF-MEMS switch in order to achieve better control and switching conditions. Simulation results show significant reduction in impact velocity (which results in less than 5 times impact force than nominal step pulse conditions) and settling time maintaining good switching speed for the pull down phase and almost elimination of the high bouncing phenomena during the release phase of the switch.

Lifetime effects of drive voltage for a commercially-available ohmic-contact RF MEMS switch

“…To explain the observed lifetime-biasing voltage trend, we explore the hypothesis that impact velocity plays an important role in switch lifetime [2]- [4], [7]. The 1-D Euler-Bernoulli model for beam motion described in [11] was used to simulate the switch landing times and impact velocity at the first contact.…”

“…For instance, several studies have been performed on developing soft-landing waveforms to reduce or eliminate bouncing [1]- [4]. Detailed modeling efforts have also examined voltage and gas damping contributions to analyze and minimize switch bouncing behavior [5]- [7].…”

On the investigation of a reliable actuation control method for ohmic RF MEMS switches

“… Finally, Taguchi's optimization technique has been applied to modify the actuation pulse in order to further improve the behavior of the switch [17]. where: is the time needed for the first contact to occur and is the maximum impact force measured during the pull-down phase.…”

“…However, the implementation of Taguchi's statistical optimization method [15][16], which is based on Orthogonal Arrays (OA), with Coventorware simulations, shows very good results as it takes into account and other factors like perforation, fringing fields and damping [17].…”

Characterization and reliability studies towards piezoelectrically actuated RF-MEMS switches

“…This method may help to mitigate stiction caused by various reasons. An increased restoring force can be achieved by optimizing the thickness, length or shape of the mov-able cantilever or membrane [22,41]. The trade-off between the actuation voltage and the restoring force should be carefully considered [22].…”