The influence of metal film, placed near a piezoelectric lateral electric field resonator on its characteristics

The effect of a thin metal film on the characteristics of a piezoelectric resonator with a lateral electric field is studied theoretically and experimentally. We studied two resonators based on PZT piezoceramic plates 3.56 and 4.46 mm thick with a resonant frequency of ~ 96 kHz. It was found that with an increase in the gap between the free side of the piezoelectric resonator and a thin aluminum film, the parallel resonance frequency and the maximum value of the real part of the electric impedance increase and reach saturation. In this case, the relative change in these values with a change in the gap width from 0 to 0.3 mm increases with decreasing resonator thickness. As for the frequency of the series resonance and the maximum value of the real part of the electrical admittance, they practically do not change. The experimental results are in good agreement with theoretical data. The change in these values with a temperature change in the range of 25-50C was measured. As a whole the possibility of development a micro displacement meter in the range 0-0.3 mm is shown, and the possibility of compensating the temperature deviation of the frequency of parallel resonance is analyzed.