Theoretical Analysis and Validation of PMN-PT Single Crystals-Based Phased Array Ultrasonic Transducer With Dematching Layers

Theoretical analysis and validation were conducted on Pb(Mg $_\text{1/3}$ Nb $_\text{2/3}$ )O $_\text{3}$ -PbTiO $_\text{3}$ (PMN-PT) single crystal-based phased array ultrasonic transducers (UTs) with dematching (DM) layers. The optimized structure of the phased arrays changes the vibration mode, where sound energy is primarily generated by the vibration of the upper surface of the arrays. This energy then transfers to the matching layer structure, thereby improving the utilization rate of acoustic energy. The DM layer-based phased arrays also exhibit a 12.66% broader $-$ 6-dB bandwidth (BW) and 5.62-dB higher relative sensitivity (RS) compared to traditional design (TD) phased arrays, which indicates that the DM layer structure can enhance the longitudinal resolution, clarity, and penetration depth of ultrasonic imaging. Moreover, the sound pressure $\textit{P}_{\text{max}}$ of DM-based phased arrays is 63.4% higher than that of TD phased arrays, suggesting an increased penetration depth of ultrasound imaging. The practical test results further confirm these findings, with the $-$ 6-dB BW of DM layer-based phased arrays being 12.85% broader and the RS of the modified arrays being 5.79 dB higher than traditional arrays. Consequently, the improved electrical and acoustic performance of DM layer-based phased arrays compared to conventional phased arrays affirms the effectiveness of the DM layer structure in enhancing the properties of the UT.