Self-resonant piezoelectric thick films for sensing applications

The behaviour of piezoelectric thick films based on a PZT paste screen-printed and fired on alumina substrates has been investigated around their resonant frequencies. Experimental results relative to circular layers are reported, which show the influences on the impedance spectra around resonance owing to lead oxide content in the paste, layer thickness and poling field. These early results suggest that this, so far overlooked region of operation, might be advantageously exploited for sensing applications, stimulating the migration in the low-cost field of thick film technology of operating principles and devices from more costly technologies.