Electrothermal-driven gap adjustable MEMS comb structure: modeling and simulation of the equivalent circuit macromodel

Theoretical model of gap adjustable comb structure has been presented in this paper. This structure can be used to increase the sensitivity of sensor. As an example, an electrothermal-driven gap adjustable comb structure has been proposed, and the mechanical–electrical coupling equations of the system have been derived. According to the coupling equations, a macromodel of the comb structure has been presented through the combine of equivalent circuit method and nodal analysis method. Simulation of the macromodel has been carried out with SPICE, and the result agreed with the FEA result in a certain range of accuracy. The result has also been compared with theoretical analysis, which coincide the theoretical solution fully. Amplitude modulation characteristics of the gap adjustable comb structure have also been studied with SPICE in this paper.