Non-contact thermoacoustic detection of embedded targets using airborne-capacitive micromachined ultrasonic transducers

作者：Nan Hao^*; Boyle Kevin C; Apte Nikhil; Aliroteh Miaad S; Bhuyan Anshuman; Nikoozadeh Amin; Khuri Yakub Butrus T; Arbabian Amin

来源：Applied Physics Letters, 2015, 106(8): 084101.

DOI：10.1063/1.4909508

A radio frequency (RF)/ultrasound hybrid imaging system using airborne capacitive micromachined ultrasonic transducers (CMUTs) is proposed for the remote detection of embedded objects in highly dispersive media (e. g., water, soil, and tissue). RF excitation provides permittivity contrast, and ultra-sensitive airborne-ultrasound detection measures thermoacoustic-generated acoustic waves that initiate at the boundaries of the embedded target, go through the medium-air interface, and finally reach the transducer. Vented wideband CMUTs interface to 0.18 mu m CMOS low-noise amplifiers to provide displacement detection sensitivity of 1.3 pm at the transducer surface. The carefully designed vented CMUT structure provides a fractional bandwidth of 3.5% utilizing the squeeze-film damping of the air in the cavity.

• 出版日期2015-2-23