LiTaO3 ultrasonic transducer excited by lateral electric field

Thickness extension mode excited by electric field across the thickness of piezoelectric substrate has long been used for various applications. In the present study, the properties of thickness extension mode excited by lateral electric field on LiTaO₃ have been investigated using the extended Christoffel-Bechmann method. It is found that the Lateral field excitation (LFE) coupling factors for a-mode (quasi-extensional mode) reaches its maximum value of 17.4% on X-cut LiTaO₃. The characteristics of an LFE device made of X-cut LiTaO₃ have been investigated and the LFE device was used for the design of a high frequency ultrasonic transducer. The characteristic of the LiTaO₃ LFE ultrasonic transducer was analyzed with the traditional KLM model and tested using traditional pulse/echo method. A LiTaO₃ LFE ultrasonic with the center frequency of 33.18 MHz and the -6dB bandwidth of 29.99% was acquired, which was well in agreement with the results of the KLM model. Further analysis suggests that the LiTaO₃ LFE device has great potential in the design of broadband high frequency ultrasonic transducers.