SUMMARY

High frequency ultrasound imaging is of considerable importance to a broad range of applications from small animal imaging to photoacoustics with the desired resolution and operation frequency steadily increasing. Among the available devices, phased array systems comprised of CMUT elements possess several preferable characteristics, such as simpler fabrication methods, simpler integration to electronics, and greater variety of geometries. Ensuring adequate performance from such systems requires a comprehensive analysis of design parameters. In this proposed work, we utilize a comprehensive model to determine the performance limitations of high frequency CMUT arrays and the effect of different design parameters on its performance. Receiver performance is compared through parameters extracted from simulations, namely, thermal mechanical current noise, plane wave pressure sensitivity, and pressure noise spectrum. Transmitter performance is compared through simulated pulse-echo response from a perfect planar reflector and thermal mechanical current noise limited SNR. Limiting factors of the frequency response are observed to be Bragg’s resonance, and crosstalk actuated fundamental and antisymmetric array modes. Based on these results a design methodology is proposed, validity of which will be tested by experiments on different arrays including a 1-D CMUT array with 40 MHz center frequency for IVUS applications.