A surface micromachined comb drive with superior stability for application as an actuator

This paper presents results of ongoing research on fundamental issues related to comb drive, including mechanical and electrical properties. Attention is mostly focused on the case when comb drive is used as a power source with a cantilever beam attached to the moving plate. FEM simulations are carried out to show the resonant behaviour of balanced and unbalanced comb drive. Fringing effect, which helps to actuate the comb drive, is modeled. Different measurement approaches in frequency domain are discussed. Theoretical formulas are derived and analyzed. In this work we designed and fabricated both balanced and unbalanced comb drives using MUMPs (Multi-user MEMS Processes) technology. Balanced comb drives exhibit superior stability both in SEM observations and spectrum analysis. Formulas governing the spectrum are experimentally verified by mixing frequency measurements