Comparative study of lithium niobate crystal cuts for use as high-voltage acoustic wave sensors

A comparison study between Y+36° lithium niobate (LiNbO₃) and 0° X-cut LiNbO₃ was performed to evaluate the influence of crystal cut on the performance of a piezoelectric high-voltage (HV) sensor. The acoustic wave propagation time was monitored prior to, during, and after applying three different HV source types to the crystal. Direct current (DC), alternating current (AC), and pulsed voltages were used. Data show that the voltage-induced shift in the acoustic wave propagation time scales quadratically for DC and AC voltage for the X-cut crystal. For the Y+36° LiNbO₃ crystal, the acoustic wave arrival time scales linearly with DC voltage and quadratically with AC voltage. When applying 5 μs voltage pulses to the crystal, the voltage-induced shift scales linearly with voltage for both crystal cuts. Data suggest LiNbO₃ has a frequency sensitive response to voltage and the influence from the crystal cut is significant when applying AC and pulsed voltage to the crystal.