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Proceedings Paper

Design of RF MEMS switches without pull-in instability
Author(s): W. Cyrus Proctor; Gregory P. Richards; Chongyi Shen; Tyler Skorczewski; Min Wang; Jingyan Zhang; Peng Zhong; Jordan E. Massad; Ralph Smith
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Paper Abstract

Micro-electro-mechanical systems (MEMS) switches for radio-frequency (RF) signals have certain advantages over solid-state switches, such as lower insertion loss, higher isolation, and lower static power dissipation. Mechanical dynamics can be a determining factor for the reliability of RF MEMS. The RF MEMS ohmic switch discussed in this paper consists of a plate suspended over an actuation pad by four double-cantilever springs. Closing the switch with a simple step actuation voltage typically causes the plate to rebound from its electrical contacts. The rebound interrupts the signal continuity and degrades the performance, reliability and durability of the switch. The switching dynamics are complicated by a nonlinear, electrostatic pull-in instability that causes high accelerations. Slow actuation and tailored voltage control signals can mitigate switch bouncing and effects of the pull-in instability; however, slow switching speed and overly-complex input signals can significantly penalize overall system-level performance. Examination of a balanced and optimized alternative switching solution is sought. A step toward one solution is to consider a pull-in-free switch design. In this paper, determine how simple RC-circuit drive signals and particular structural properties influence the mechanical dynamics of an RF MEMS switch designed without a pull-in instability. The approach is to develop a validated modeling capability and subsequently study switch behavior for variable drive signals and switch design parameters. In support of project development, specifiable design parameters and constraints will be provided. Moreover, transient data of RF MEMS switches from laser Doppler velocimetry will be provided for model validation tasks. Analysis showed that a RF MEMS switch could feasibly be designed with a single pulse waveform and no pull-in instability and achieve comparable results to previous waveform designs. The switch design could reliably close in a timely manner, with small contact velocity, usually with little to no rebound even when considering manufacturing variability.

Paper Details

Date Published: 31 March 2010
PDF: 10 pages
Proc. SPIE 7644, Behavior and Mechanics of Multifunctional Materials and Composites 2010, 76442C (31 March 2010); doi: 10.1117/12.848045
Show Author Affiliations
W. Cyrus Proctor, North Carolina State Univ. (United States)
Gregory P. Richards, Kent State Univ. (United States)
Chongyi Shen, The Univ. of Iowa (United States)
Tyler Skorczewski, Univ. of California, Davis (United States)
Min Wang, Northern Illinois Univ. (United States)
Jingyan Zhang, The Pennsylvania State Univ. (United States)
Peng Zhong, The Univ. of Tennessee, Knoxville (United States)
Jordan E. Massad, Sandia National Labs. (United States)
Ralph Smith, North Carolina State Univ. (United States)


Published in SPIE Proceedings Vol. 7644:
Behavior and Mechanics of Multifunctional Materials and Composites 2010
Zoubeida Ounaies; Jiangyu Li, Editor(s)

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