Capacitive micromachined ultrasonic transducer for ultra-low pressure detection

This paper presents a novel approach for ultra-low pressure detection using a capacitive micromachined ultrasonic transducer (CMUT) as the sensing element. The working principle depends on the resonant frequency shift of the CMUT under the measured pressure. The finite element method (FEM) simulations were employed to study the sensing performance of the CMUT. The results demonstrated the feasibility and superiority of the CMUT for ultra-low pressure measurement. The resonant frequency varies linearly with the measured pressure. The pressure sensitivity can be improved by increasing the bias DC voltage for a certain CMUT. Additionally, the effects of structure parameters such as electrode dimension, electrode separation distance, membrane radius and thickness on the pressure sensitivity were also studied, which will contribute to the design and operation of the CMUT-based ultra-low pressure sensor.