1 MHz ultrasonic needle transducer

Broadband pointwise contacting excitation of Lamb waves into sample materials remains a problem. We present a design of a broadband ultrasonic contacting needle transducer. A prototype was built and a transmit waveform was measured using a laser Doppler vibrometer. 1 MHz bandwidth is achieved at -18dB level while the center frequency was 210 kHz. This kind of transducer could permit quantifying the stiffness of plate- and fiber-like samples in industrial environments.