A Dynamic Model of Microscale Contact Breaking in RF MEMS Switches

For many applications, radio frequency microelectromechanical systems (RF MEMS) switches require very fast switching times so that they are capable of switching thousands of times each second. Contact adhesion tends to slow switches by increasing the time required to break the contact and open the switch. Previous work showed that typical switches have a contact opening time exceeding 1 ms, which is far too slow for many applications. This paper presents a dynamic, transient model to predict the time required to break the contact. The model considers both the motion of the switch body and the adhesion at the contact. The model has been validated by comparing it to experimental data. The model shows that vibrations in the switch body can be instrumental in dramatically reducing contact opening time by a factor of nearly 1000, leading to acceptable switch speeds.