Analysis of Thermally Actuated RF-MEMS Switches for Power Limiter Applications

This paper presents a multiphysics analysis of thermally actuated RF MEMS switches for use in power limiter applications. RF MEMS switches can self-actuate when operating under high RF power levels. The level of power at which the switch actuates, can be varied by controlling the applied dc actuation voltage. MEMS switches are, therefore, proposed for use in power limiter applications. The objective of the multiphysics analysis presented in this paper is to combine thermal analysis, with mechanical analysis and RF analysis to derive a relationship between the RF power needed for self-actuation and the dc voltage applied to the thermal actuator. A thermally actuated MEMS switch is fabricated and tested. It is used as a test bed for demonstrating the proposed multiphysics analysis. The experimental results obtained for this switch confirm the approach used to construct a multiphysics analysis for thermally actuated MEMS switches. The results obtained also demonstrate that thermally actuated MEMS switches offer improved device sensitivity, when used in power limiter applications, in comparison with their counterparts electrostatically actuated MEMS switches.