A Soft-Landing Waveform for Actuation of a Single-Pole Single-Throw Ohmic RF MEMS Switch

Dielectric Charge Control in Electrostatic MEMS Positioners/Varactors

“…The selection of the control voltage is determined by the current capacitance value, or, according to (17), by the current position x(t). We consider a sequence of discrete values of the position x n = x(nT s ) and the dielectric charge Q n = Q d (nT s) and introduce them into the system.…”

“…[14]- [16] develop and validate through experimental fitting a phenomenological model for dielectric charging and discharging under either positive or negative applied voltages in RF MEMS switches. According to this, waveform signal changes [17] and periodic switching of voltage polarity [14]- [16] have been proposed and demonstrated as promising ways to reduce the effects of dielectric charging. Indeed, since the electrostatic force is attractive, MEMS devices can be actuated by either positive or negative voltages.…”

Observation and Understanding of the Initial Unstable Electrical Contact Behaviors

“…8,9,15 Contact bounces in MEMS switches have been observed and studied in. [16][17]18,19 These papers mainly focus on the issue of contact bounce suppression by modifying actuation signals. The challenge is to perform high-speed commutation with near-zero impact velocity to avoid bounces.…”

Characterization and reliability studies towards piezoelectrically actuated RF-MEMS switches

“…McGruer et al mention that using a specially tailored actuation pulse may significantly reduce the impact force [35]. Czaplewski et al propose a soft-landing waveform, which consists of an actuation pulse (larger than pull-in voltage), a coast time at 0 V and a hold voltage (slightly larger than pull-out voltage) [39,40]. The movable electrode gets kinetic energy to contact during the actuation pulse; the restoring force and damping slow the movable electrode to near-zero impact velocity during coast time; the hold voltage maintains the switch in contact-state.…”

“…Goldsmith et al apply a high voltage pulse (larger than the pull-in voltage) to actuate the switch, then decrease the voltage to a medium value (larger than the pull-out voltage) to maintain the movable electrode in contact [53]. The waveform suggested by Czaplewski et al [39] and Sumali et al [40] have the same idea to reduce charging as Goldsmith et al, and they further shorten the duration of the high actuation voltage to slightly longer than the switching time.…”