Lamb-wave electroacoustic voltage sensor

The effect of a bias electric field on the phase velocity of Lamb waves propagating in a piezoelectric plate has been investigated in order to develop an electroacoustic voltage sensor. Experiments were performed on Y X and Y Z LiNbO3 Lamb-wave delay lines, used as the stabilizing element in the feedback loop of an oscillator, by measuring the fractional frequency change produced by a bias electric field normal to the plate surfaces. The results obtained have shown that Lamb-wave sensors can exhibit a higher sensitivity and a better linearity than the corresponding Rayleigh-wave devices.