Modeling and analysis of a liquid-level sensor utilizing an evanescent field of a trapped-energy vibrator

Equivalent-network modeling and analysis have been presented for a liquid-level sensor that utilizes an evanescent field created by a trapped-energy vibrator. The network is constructed by modifying an electric network representing the propagation of thickness-vibration mode along the piezoelectric plate. Simulation has been performed for the sensors utilizing trapped-energy vibration modes of conventional type and the backward wave type. It is revealed that the computed results show a similar trend in variation to the experimental results that have been examined so far.