Substrate effect in squeeze film damping of lateral oscillating microstructures

We present a new squeeze film damping model for lateral oscillating microstructures which for the first time accounts for the increased damping created by proximity to the substrate. The proposed model improves the estimation of damping by a factor of 2 to 4 when the distance to the substrate is less than or equal to the gap between oscillating plates. The closed-form solution of this model agrees with the predictions of a FEM model within 12%. Experimental results show that the new model improves the accuracy of the estimated damping by approximately a factor of 2.