Effect of residual stress on electromagnetic characteristics of capacitive RFMEMS Switch

This paper presents the effect of the thermally induced residual stress on the RF characteristics of capacitive shunt Symmetric Toggle MEMS Switch (STS). The formation of residual stress is attributed to the thermal loading-unloading cycle of the switch at high temperatures during microfabrication process. Initially, 3D nonlinear FEM models are developed to simulate the thermal loading cycle and resultant deflection profile and induced residual stress are obtained. The STS switch is modeled in a shunt configuration on a 50Ω coplanar transmission line and corresponding scattering parameters (S-parameters) are obtained with and without considering residual stress. The RF characteristics has been improved due to the presence of the residual stress for the STS switch considered in this work.