Sensors & Transducers Magazine (S&T e-Digest), Vol.66, Issue 4, April 2006, pp.526-533 S S S e e e n n n s s s o o o r r r s s s & & & T T T r r r a a a n n n s s s d d d u u u c c c e e e r r r s s s ISSN 1726-5479 © 2006 by IFSA http://www.sensorsportal.com Pull-In Voltage of Fixed-Fixed End Type MEMS Switches with Variative Electrostatic Area Hamed Sadeghian, Ghader Rezazadeh, Ehsan Malekpour, Ayla Shafipour Mechanical Engineering Department, Urmia University, Urmia, IRAN Tel. +98-914-145-1407, fax. +98-441-277-7022 E-mail: Hamed.sadeghian@gmail.com g.rezazadeh@mail.urmia.ac.ir Received: 28 January 2006 Accepted: 21 April 2006 Published: 25 April 2006 Abstract: In this paper we developed a new approach to calculation of pull-in voltage of fixed- fixed end type MEMS switches. In the previous works Pull-in voltage has been calculated on a lumped model, when one of them used a distributed model by assuming the electrostatic area is applied the whole of the surface of the beam. In the present work, we used a distributed model to determinate the pull-in voltage. To do this the nonlinear governing equation of the beam with non- uniform electrostatic pressure that applied in the part of beam has been derived. The derived nonlinear equation has been solved numerically and has been showed that the results of our approach are more accurate than the other previous works. Keywords: MEMS, distributed model, electrostatic pressure ________________________________________________________________________________ 1. Introduction The advent of monolithic integration of micromechanical structure with electronics requires the development of simulation and analysis tools that can allow coupled circuit and micromechanical simulation [1]-[8]. Pull-in phenomenon is a discontinuity related to the interplay of the elastic and electrostatic pressures. The determination of the pull-in voltage and position requires the solution of 526