Design and simulation of a tunable comb-drive actuator with a wide frequency tuning range and low pull-in voltage

Abstract

The presented paper describes the design, simulation, and analysis of a novel tunable comb-drive actuator that aims to increase the range of tuning resonance frequency while reducing the pull-in voltage. The conventional comb resonator has a limited resonant frequency tuning range, and hence, modifying the spring stiffness of the structure is crucial to obtain a tunable comb resonator. The proposed design includes eight flexible beams on each side that support a set of comb finger parts. The actuator achieves the goal of shifting the resonance frequency both downwards and upwards by utilizing Serpentine nested-folded beams. A triangular comb with non-uniform varied finger lengths combined with variable gap fingers is designed to adjust the frequency downwards, while a comb with constant finger lengths combined with variable gap fingers is designed to adjust the frequency upwards. To simulate and design the structure, the IntelliSuite software is utilized. The results show that the actuator has a primary resonant frequency of 3052 Hz, which can be lowered to 335 Hz by applying a tuning voltage of 74 V to the downward tuning part. Similarly, the resonant frequency can be increased to 3159 Hz by applying a tuning voltage of 60 V to the upward tuning part. The resonator achieves a maximum frequency tuning range of 90%, and the simulation results are in good agreement with the theoretical predictions. However, it is worth noting that the size of this resonator is relatively small, approximately 1077 × 328 μm2. This innovative design offers potential applications in various fields, including micro-electromechanical systems (MEMS), micro-optics, and microsensors. Overall, the presented work demonstrates the feasibility of achieving a tunable comb resonator with a significantly improved resonant frequency tuning range and reduced pull-in voltage.