Simulation and experimental characterization of a 2-D, 3-MHz capacitive micromachined ultrasonic transducer (CMUT) array element

In this paper, a 400-μm×400-μm, 2-D capacitive micromachined ultrasonic transducer array element is experimentally characterized, and the results are found to be in agreement with theoretical predictions. As a receiver the transducer has a 1.8×10 ^-7 nm/√Hz displacement sensitivity, and, as a transmitter, it produces 16.4 kPa/V of output pressure at the transducer surface at 3 MHz. The transducer also has more than 100% fractional bandwidth around 3 MHz, which makes it suitable for ultrasound imaging. The radiation pattern measurements indicate a 3-dB acceptance angle of ±35 degrees in agreement with the theoretical predictions