Electrostatic forces in fixed-fixed microbeams under direct and fringing field effects

We propose simple approximate expressions for capacitance and electrostatic force for fixed-fixed beam-based MEMS/NEMS devices subjected to direct electrostatic and fringing field effects. The configuration that are considered for study are fixed-fixed beam and bottom electrode, fixed-fixed beam and side electrode, and a combination of beam, bottom electrode and side electrode. The expressions are evaluated based on the numerical result obtained using FEA analysis in COMSOL software. The accuracy of the proposed formulae is compared with available literature. The formulae proposed in this paper are valid for a wide operating range and they can also be used for array applications.