IMPEDANCE MODEL OF A PIEZOELECTRIC SENSOR DERIVED FROM EXPERIMENTAL RESPONSES
Paramita Banerjee1, Ratna Ghosh2, Bhaswati Goswami2
1Department of Applied Electronics and Instrumentation Engineering, Gurunanak Instituteof Technology, Kolkata 700114, India
2Department of Instrumentation and Electronics Engineering, Jadavpur University 2nd Campus, Kolkata 700098, India
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The aim of the paper is to propose an electrical equivalent series model of a piezo based sensor, in terms of its impedance, considering the Thevenin equivalent looking back impedance from the sensor side. As the sensor consists of a piezo element attached with a metallic strip, the model should explain the contribution of the piezo as well as the substrate separately in the overall impedance response. The model for piezo element consists of three passive impedance blocks, connected in series whereas there are four blocks in the model of the sensor. The fourth block here is mainly to represent the additional characteristics appearing due to the addition of the substrate. The blocks have their own individual contributions in the overall impedance response, though they are not totally decoupled. The simulated responses of the piezo as well as the sensor, using this model has been validated against experimental impedance responses. The model proposed in this study can be used to simulate the impedance phase responses as well as the impedance magnitude responses of the piezo and the sensor.
Impedance response; piezo element; sensor; impedance model