Novel High-Frequency Air Transducers

Ultrasonic transducers operating in air in the frequency range of 1–10MHz have major applications in robotics and nondestructive evaluation. For robotics applications, high-frequency air transducers make possible range measurements with a resolution in the 30–100 μm range. For nondestructive evaluation, it is possible to make transmission C-scan systems operating in air for the inspection of composites, green ceramics, and even metals at elevated temperatures. In this work, we report on the use of ligneous materials as a matching layer for PZT-based transducers.