Novel capacitance evaluation model for microelectromechanical switch considering fringe and effect of holes in pull-up and pull-down conditions

This paper reports a model and investigates into capacitive studies of microelectromechanical system switch through considerations of material’s behavior on various parameters like dielectric thickness, thickness and width of bridge structure and also with distance between two electrodes including fringe field effect on pull up and down capacitance. The pull up capacitance and pull-down capacitances are investigated considering effect of fringe field and holes independently as well as combined together. In pull up state, the total capacitance is found to be 6.9945 fF in which three components of the capacitance \( C_{1,u} \), \( C_{2,u} \) and \( C_{3,u} \) contribute 1.1624 fF (16.61%), 2.1924 fF (31.34%) and 3.6397 fF (52.03%) respectively. In pull down state, the total capacitance is found as 2.1439 pF and capacitance sharing of each component (\( C_{1,d} \)), (\( C_{2,d} \)) and (\( C_{3,d} \)) is 0.6503 pF (30.33%), 1.1164 pF (52.07%) and 0.3772 pF (17.59%) respectively. The pull-down capacitance (\( C_{t,d} \)) and pull up capacitance (\( C_{t,u} \)) ratio is also calculated and \( \left( {\frac{{C_{t,d} }}{{C_{t,u} }}} \right)_{max} \) using model is found as 521.64. The capacitance ratio range is also calculated and range is 48.41–521.64. This model can be used to measure the capacitances in symmetric and asymmetric microelectromechanical switch with error range 2–5%.