Abstract: The influence of outside inertial shock combined with RF signal voltages on the properties of a shunt capacitive MEMS switch encapsulated in a low vacuum environment is analyzed considering the damping of the air around the MEMS switch membrane.An analytical expression that approximately computes the displacement induced by outside shock is obtained.According to the expression,the minimum required mechanical stiffness constant of an MEMS switch beam in some maximum tolerated insertion loss condition and some external inertial shock environment or the insertion loss induced by external inertial shock can also be obtained.The influence is also illustrated with an RF MEMS capacitive switch example,which shows that outside environment factors have to be taken into account when designing RF MEMS capacitive switches working in low vacuum.While encapsulating RF MEMS switches in low vacuum diminishes the air damping and improves the switch speed and operation voltage,the performances of a switch is incident to being influenced by outside environment.This study is very useful for the optimized design of RF MEMS capacitive switches working in low vacuum.

Key words: reliable operation condition, RF MEMS switch, low vacuum, mechanical shock, air damping