Effect of the Electrical Conductivity of a Film on the Characteristics of an Radial Electric Field Excited Acoustic Resonator

The results of a study of the influence of the electrical conductivity of a thin film deposited on the free end of a radial electric field excited acoustic resonator field or located in its immediate vicinity on the resonator characteristics are presented. Three situations were considered: there is no conductive film, the film is deposited directly on the resonator free end, and the film is located at a short distance from the resonator free end. In all three cases, the electrical impedance of the resonator was calculated and measured in a wide frequency range of 1–1500 kHz. For the first time, the material constants of piezoceramics were refined for a free and short-circuited resonator and it was shown that these constants coincide with each other with good accuracy. It is shown that a decrease in the resonator thickness and an increase in the gap between the electrodes increase its sensitivity to the presence of a conductive film at a short distance from the resonator end.