Abstract: The pull-in voltage of RF MEMS switches at different actuations is presented.When the actuation voltage is a pulse voltage,the movement of the switch beam is in a vibration state rather than quasi-static,so the pull-in voltage is different from the quasi-static condition and is called dynamic pull-in voltage.It is about 92% of the quasi-static pull-in voltage.Following the simple formula of the spring coefficient of a beam and the exact formula of the capacitor for the switch,the quasi-static and dynamic pull-in voltages of the clamped-clamped beam switch on CPW are analyzed,and the damping effect is also included.The damping reduces the difference between the two kinds of pull-in voltages.Finally,the influence of the RF input power on the pull-in voltage is analyzed.The input power decreases the pull-in voltage,reducing the pull-in voltage to zero at a certain power,and then making the switch self-actuate.

Key words: RF MEMS, switch, pull-in voltage, quasi-static, dynamic, damping