Signal to noise ratio optimization for a CMUT based medical ultrasound imaging system

摘要

CMUTs offers key performance benefits compared to their piezoelectric counterparts. However, CMUTs are not widely adopted in commercial ultrasound imaging systems due to low signal to noise ratio (SNR) in the obtained images. Tunable parameters of the CMUT include the membrane material, radius, thickness, gap height, electrode size, and bias voltage. The aim of this work is to optimize these parameters to provide a solution for low SNR problem of CMUTs. In medical imaging, the device will be used in pulse echo mode for which both good receive sensitivity and high output pressure is required. Optimizing these performance metrics will end up in conflicting design parameters, such as a high gap for large pressure output whereas a small gap for better receive sensitivity. In this work, we develop a methodology for the investigation of the round-trip behavior of the transducer and try to co-optimize transmit and receive characteristics of the device to maximize the SNR of the received signal by tuning the bias voltage.