Fabrication of Dual-Frequency Duplex CMUTs in a Vertically Stacked Topology for Acoustic Angiography

In this work, we propose a novel CMUT design consisting of independently optimized low-frequency transmitters and high-frequency receivers in a vertically stacked topology, which has overlapping transmit and receive apertures with large frequency separation. Moreover, a 3-dB transmit spectrum width is measured for low-frequency devices from 1.6 MHz to 2.62 MHz, and the high-frequency receiver has a 3-dB bandwidth from 8.08 MHz to 13.64 MHz in immersion.