LFE ultrasonic transducers based on inversion layer LiNbO3 for medical imaging

High frequency broadband lateral-field-excited (LFE) ultrasonic transducers were fabricated using inversion layer lithium niobate (LiNbO₃) single crystal plate. The transducer developed for this study used an X-cut LiNbO₃ thin plate with an active element thickness of 152μm relative to the designed center frequency of 33MHz. 28% inversion layer thickness ratio was obtained by grinding the half-thickness inversion layer plate instead of precision treatment control. The measured impedance showed even harmonic resonances were excited by the lateral electrodes structure in X-cut inversion layer LiNbO₃ plate. From the pulse-echo response, the center frequency of the transducer was 31MHz and the bandwidth was 69%, compared to the 34% bandwidth of the LFE transducer based on non-inversion layer X-cut LiNbO₃ Plate.