Improving the Performance of Low Frequency Adjustable Shoulder Resonator (MEMS) Using the Finger Overlap Surface Change Method for Use in Active Sonars

In this paper, an electrostatic comb drive resonator structure in the frequency range below 3 kHz with the ability to resonate at several frequencies is designed, simulated and analyzed for use in active sonar. With the studies performed on the research background, one of the challenges of designing the comb drive resonator structure of electrostatic comb drive is to increase the frequency adjustment percentage, increase the frequency adjustment range and decrease the initial resonant frequency and voltage applied to the resonator structure; Here, to solve these challenges, the method of fingers with different non-uniform lengths, the method of changing the lengths of fingers non-uniformly and increasing the number of folded beams are suggested, respectively. In the following, the relationships related to the proposed structure, beams, comb drives and resonance frequency are researched and studied. The initial resonant frequency of this micro resonator was evaluated using two different software that are very close to each other (2549 Hz and 2384 Hz). This proximity to software results and analysis confirms the reliability of this structure. By increasing the voltage from 0 to 65 volts, this frequency can be adjusted from 2549 Hz to 280 Hz, which increases the frequency tuning range; Therefore, here we will have 88% change of resonant frequency, which in comparison with the work done, the range of resonant frequency adjustment has increased by 31%.