We study a capacitive MEMS switch composed of two clamped-clamped exible microbeams. We first develop a mathematical model for the MEMS switch where the upper microbeam represents the ground transmission line and the lower one represents the central transmission line. An electrostatic force is applied between the two microbeams to yield the switch to its ON and OFF states. We derive the equations of motion of the system and associated boundary conditions and solve the static and dynamic problems using the differential quadratic method. We show that using only nine grid points gives relatively accurate results when compared to those obtained using FEM. We also examine the transient behavior of the microswitch and obtain results indicating that subsequent reduction in actuation voltage, switching time, and power consumption are expected along with relatively good RF performances. ANSYS HFSS simulator is used in this paper to extract the RF characteristics of the microswitch. HFSS simulation results show that the insertion loss is as low as ？0.31？dB and that the return loss is better than ？12.41？dB at 10？GHz in the ON state. At the OFF state, the isolation is lower than ？23？dB in the range of 10 to 50？GHz. 1. Introduction In telecommunication, MEMS devices offer a multitude of components to replace the classical semiconductor circuits elements. Microswitches and microresonators are used in a series of applications extending from the mobile phone and wireless networks to fiber-optic communication and multiplexed networks [1–3]. The major tasks of these devices are switching, filtering, and tuning. The equivalent circuit elements to these devices (PIN diode and Field-Effect Transistors FET) are generally characterized by high power consumption, low reliability, and high-manufacturing costs. In addition, they present unsatisfactory performance for high signal frequencies [4]; they give a high insertion loss and inadequate isolation at ON and OFF switching state. Radio frequency MEMS (RF-MEMS) components have been recently widely developed and used in several applications. In particular, RF-MEMS microswitches are used in telecommunication applications to replace the traditional microelectronic switches (diodes and transistors). These microswitches present an improved insertion loss and good isolation during the “ON/OFF” switching states [4]. However, they are limited by the high actuation voltage (up to 30 volts) and slow switching time (nearly 300 microseconds). As a result, several researchers want to ameliorate the switching time, minimize the actuation
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