An Ultra-Wideband Capacitive Micromachined Ultrasonic Transducer (CMUT) Array for Acoustic Angiography: Preliminary Results

Acoustic angiography (AA) has traditionally been limited by the lack of transducer arrays that are able to transmit at low (1-5 MHz) frequencies and also receive at high (>10 MHz) frequencies. We have designed and fabricated a 1D CMUT array capable of operating with a broad bandwidth, covering the desired frequency range. This array has been tested in preparation for integration into a hand-held probe for AA. A 32-element subsection of this array was wire bonded to a chip carrier which was then placed in an oil tank for analysis. Our initial measurements show that the array is suitable for AA. The characterized array exhibits 130% fractional bandwidth (FBW) at a center frequency of 8.5 MHz enabling a target transmit frequency of 3.5 MHz, a target receive frequency to receive the higher harmonics including the fourth harmonic (14 MHz), and a mechanical index (MI) of 0.33.