Comparison of Voltage-Mode and Charge-Mode amplifiers for Interfacing piezopolymer transducers to SHM electronic systems

Flexible interdigital transducers fabricated with piezopolymer film are applied for SHM of composite material with guided waves at frequency below 1 MHz. This type of transducers has high impedance respect to piezoceramic equivalents and suffer of signal degradation due to stray capacitances and common mode noise. The interfacing with electronic systems has been improved by using a custom designed charge amplifier and described in this work.