Design And Fabrication Of High-Frequency Ultra-Wideband 1d Cmut Arrays For Acoustic Angiography Applications - Preliminary Results

For superharmonic imaging applications involving the use of microbubble contrast agents, transducers that can transmit energy at low frequencies (less than 5 MHz) to excite the microbubbles, and at the same time detect scattered echoes at higher harmonics (greater than 20 MHz) are essential. We explored the advantages of a thin silicon plate with an added central mass combined with a reduced bottom electrode area to further improve the bandwidth of 1D capacitive micromachined ultrasonic transducer arrays. FEM simulation results show that the fabricated devices can transmit at low frequency (<3 MHz) and receive echoes at high frequency (beyond 30 MHz). This translates into a 180% fractional bandwidth at 17 MHz for the fabricated 1D CMUT array.