Development of PZT-based 18 MHz 2D pMUT array with PDMS waveguide

For high-resolution ultrasonic imaging, an 18 MHz lead zirconate titanate (PZT) based two-dimensional (2D) piezoelectric micromachined ultrasonic transducers (pMUTs) array with polydimethylsiloxane (PDMS) waveguide are developed. The array is composed of 8 × 16 elements with a pitch of 75 μm and each element can be independently electrically excited. The structure is fabricated by micromachining. The resonance frequency obtained in air is 18.3 MHz and 18 MHz with and without PDMS waveguide filling, respectively. The displacement responses show a sensitivity of 2.6 nm/V and a bandwidth of 14% with PDMS waveguide.