In this paper, we will summarize our efforts on exploring guided acoustic waves generated by MEMS ultrasonic
transducers enabling a non-destructive, ultra-low powered, wireless SHM system. State-of-the-art SHM systems employ
bulk piezoelectric transducers. However, they are not environmentally benign (contain lead), not cost feasible for
monitoring every bridge in the U.S., require significant power for operation, lack integration capability for wireless
interrogation, need precise matching layers, and have only 25-50 percent fractional bandwidth, limiting the detection
resolution. To alleviate most of these shortcomings, a low impedance MEMS transducer, called a capacitive
micromachined ultrasonic transducer (CMUT), is explored.