RF characterization of low-voltage high-isolation MEMS series switch based on a S-shaped film actuator

This paper presents on an electrostatically actuated microelectromechanical series switch for DC to RF signals, based on a flexible S-shaped film actuator moving between two electrodes in touch mode actuation. This novel concept, in contrast to most other MEMS switches, allows a low actuation voltage design independent on the off-state gap height, which makes larger switching contact areas for low insertion loss and higher current handling capability possible, by obtaining high isolation. Furthermore, the double anchor principle avoids self-biasing and is favorable of switching higher power signals. The actuation voltages of the first prototype switches are 12 V to open and 15.8 V to close the metal contact. The RF isolation with a gap distance of 14.2 μm is better than -45 dB up to 2 GHz and -30 dB at 15 GHz despite a large switching contact area of 3500 μm².