AN IMPROVED METHOD TO DETERMINE COMPLEX ACOUSTIC-IMPEDANCE USING A PIEZOELECTRIC RESONATOR

On the basis of a propagating wave analysis, a simple method of acoustic impedance determination of material deposited on one face of a resonator is presented. In addition, an algorithm to determine the resonant parameters of the resonator from the measured frequency spectrum of the electrical impedance is provided. Using this method with the algorithm, the complex acoustic impedance is given by the electrical impedance measurement. Experimental determination of the complex viscosity of some liquids is presented as an example of the method, and it is found that the minimum detectable viscosity change is, at most, 1%.