On the mechanical behavior of a wide tunable capacitive MEMS resonator for low frequency energy harvesting applications

We present a method for tuning the resonance frequency of a comb resonator using a combination of mechanically softening and hardening springs in order to achieve a high tuning range of resonant frequency. The nonlinear behavior of the structure is due to an angle in the main beam of a crab-leg flexure. Theoretical and simulation results are done to analyze the linear, quadratic, and cubic stiffness as well as frequency changes of the comb drive actuators. The frequency response of the resonator is achieved using the Lindstedt-Poincare perturbation technique. In order to validate the theoretical analysis, the results are compared with simulation results obtained by COMSOL software.