Electro-thermal analysis of RF MEM capacitive switches for high-power applications

Self heating in electrostatically actuated RF MEM capacitive shunt switches is analyzed by coupled electrical and thermal simulations using three-dimensional finite-element analysis. The result shows that despite highly nonuniform current and temperature distributions, the self-heating effect can be approximated by lumped thermal resistances of the switch membrane and the substrate. Additionally, since the thermal resistance of thermally insulating substrates such as quartz is significant compared to that of the membrane, it is important to consider the heat transfer across both the membrane and the substrate.