Capacitive micromachined ultrasonic transducer (CMUT): Modelling and investigation of transmission performance under different driving parameters for intravascular applications

In this study, the MEMS-based Capacitive Microprocessed Ultrasonic Transducer (CMUT) element, which is promising in ultrasonic applications, has been modeled and analyzed under different parameters to investigate the behavior of this system. Experimental analysis often requires long work and high costs. Simulations are becoming more and more important to minimize time loss and costs in these studies. Matlab/Simulink was preferred for CMUT modeling because it is fast, useful and inexpensive. Modeling was done by using electrical equivalent circuits and mathematical equations belonging to the mechanical model expressing CMUT behavior. By using output pressure and membrane displacements as measurement parameters, small signal and large signal analysis under different voltages were performed and CMUT transmission performance was evaluated.Dynamic analyzes were made using different membrane materials such as Si, Poly-Si, Si3Ni4, Diamond and electrodes with different sizes and these results were compared. In addition, how the performance changes in case of stress on the membrane and how the quality factor and bandwidth are affected by the stress were also investigated. A comparison of the performance of CMUT sequences has also been made. Based on the results, it has been shown that the model, which gives fast results as well as being an economical alternative used in this study, can be used in CMUT-based ultrasound transducer designs for performance measurement and determination of the optimum values of input-output parameters such as output pressure, displacement, quality factor and bandwidth.