Rf Mems Switches, Horizontal Heat-driven Research

RF MEMS switches are widely applied in antennae, adjustable filters and phase arrays for defense and telecommunication systems, and switching matrices for satellite communication. MEMS switches have several advantages over PIN diodes or FET counterparts such as low insertion loss, high isolation, and low power consumption. The majority of MEMS switches reported to date employ electrostatic actuation which requires large actuation voltages. Besides, mechanical failures would happen during actuation of electrostatic switches. Lateral electro-thermally actuated switches have attracted numerous research efforts in recent years for their simple structures, small actuation voltage, and simple fabrication processes.A novel concept for MEMS switches employing electro-thermal actuation was introduced. The folded U-shaped beam thermal actuator and the V-shaped beam thermal actuator were modeled in one dimensional lumped mechanics. Electromagnetic characteristics of RF MEMS switches were discussed. A single-pole single-throw SPST MEMS switch based on folded U-shaped beam thermal actuator and a single-pole double-throw SPDT MEMS switch based on V-shaped beam thermal actuator were designed. The switches were fabricated using the MetalMUMPs process from MEMSCAP Company.Thermal-electro-mechanical characteristics of proposed structures have been analyzed by IntelliSuit FEA software, the results depicted a threshold voltage of SPST switch was 1V, and the driven voltage of SPDT switch was 0.3V. Electromagnetic characteristics of lateral MEMS switches were analyzed by Ansoft HFSS software. The simulation results showed the SPST switch had an isolation of -31dB at 5GHz, the insertion loss was -0.5dB and return loss was -17dB at 5GHz. And, the isolation of the SPDT switch was -55.3dB at 2GHz, the insertion loss was -3dB and return loss was -10.2dB at 2GHz.The simulation results suggest a reasonable design and a feasible process arrangement. The conclusion is constructive to deeper research in lateral MEMS switches fields and their applications.