A low profile single-element piezoelectric substrate having an inter-digitally formed electrode pattern consisted of fingers and gaps can effectively generate nondispersive surface acoustic waves without using a secondary device such as angle blocks or combs. It is easy to fabricate an IDT sensor to have a narrow bandwidth resonance frequency by simply adjusting the widths of fingers and gaps through a precision laser micromachining process. In this work, IDT sensors operating from 100 kHz to 10 MHz have been investigated and some of the results collected from benchmark studies performed on various structural components made from aircraft grade alloys, bridge steels and polymeric composite materials are reported.
doi: 10.12783/SHM2015/131