Abstract:The capacitive micromachined ultrasonic transducer (CMUT) array is one of the commonly used structures of MEMS sensors. To reduce the power consumption and improve the sensitivity of the gas sensor, the dimension and structure of the CMUT array are optimized. First, with the theoretical analysis of the firstorder lumped electromechanical vibration model, it is found that the sensitivity of the CMUT is positively correlated with the collapse voltage and they are mainly affected by the thickness of the diaphragm, the electrode spacing and the electrode radius. The parameters of CMUT are designed to meet with those requirements. Then a more practical finite element model is proposed, which combined with the structural characteristics, air damping, external circuits, elastic softening and other factors by using COMSOL Multiphysics simulation software. The theoretical analysis results are substituted into the model to further optimize the parameters of CMUT. Finally, a CMUT array with collapse voltage of 11.3 V, sensitivity of -3.253×10 17 Hz/kg, resonant frequency of 4.858 MHz and quality factor of 121.45 has been developed.