Modelling of large-scale multi-frequency CMUT arrays with circular membranes

Large-scale multi-frequency capacitive micromachined ultrasonic transducer (CMUT) arrays consist of thousands of closely packed interlaced large and small membranes for applications such as super-harmonic imaging, multi-band operation, imaging-therapy, contrast and photoacoustic imaging. An accurate nonlinear lumped equivalent circuit model including the effects of the self and mutual acoustic interactions between CMUT cells was used for modeling of multi-frequency CMUT arrays. Recently, we showed precise models for simulating the behavior of multi-frequency CMUT arrays including a few number of cells with excellent agreements with FEM and experimental results. In this work the model was extended to simulate large-scale multi-frequency CMUT arrays for realistic ultrasound applications which is not feasible with FEM analysis. The models predicted the effects of the mutual radiation impedance between cells with dissimilar sizes for complex and large-scale arrays. The effects of different biasing methods were evaluated on performance of the array for different sets of CMUT parameters. This tool can be used to optimize the performance of the multi-frequency CMUT arrays before fabrication.