A Novel Three-State RF MEMS Switch for Ultrabroadband (DC-40 GHz) Applications

Design, fabrication, and measurement results of a lateral dc-contact RF microelectromechanical systems switch for ultrabroadband applications are presented in this letter. The switch is driven by a bidirectional cascaded electrothermal actuator, which can generate larger displacements and contact forces at two directions than traditional electrothermal actuators. Because of this bidirectional actuator, the proposed switch can not only realize the off-state to on-state shifting, but also provide an additional deep off-state. The proposed switch is fabricated by MetalMUMPs process, and measurement results show that the insertion loss is less than -0.5 dB and the initial isolation is better than -22.5 dB at 0-40 GHz range. At the deep off-state, the isolation better than -30 dB can be achieved at the whole frequency range 0-40 GHz. The measurement results agree well with the theory and design.