Towards On-Chip Measurement of S-Parameters for Ultrasonic Guided-Wave SHM: Damage Localization in Aluminum Using S-Parameter Measurements

This paper investigates miniaturized hardware for active SHM based on ultrasonic guided-waves. The proposed approach relies on frequency-domain S-parameter measurements instead of time-domain pulsing and thereby trades off longer measurement times with lower actuation voltages for improved compatibility with dense CMOS chip integration. To demonstrate the feasibility of this approach, we show defect localization measurements for an aluminum plate using a benchtop vector network analyzer using 0 dBm (0.632 V ) actuation signals. The challenge of designing directional couplers in the 10 kHz – 10 MHz target frequency range of the system is discussed and ongoing work to address this challenge is presented.