Differential Structure Realization in Piezoresistive Sensor by Designing Electrode Configurations

To realize the differential structure in the piezoresistive sensor for the application where there is no condition to achieve the opposite subexcitations, an electrode-configuration-based differential structure with the subunits made of identical ingredients is designed. The subunits include “negative coefficient unit (NCU)” and “positive coefficient unit (PCU).” The electrodes and the piezoresistive material in NCU/PCU are located in three layers/one layer, and the connection line of the centers of the electrodes is parallel/perpendicular to the compressive pressure. The material thickness in NCU/PCU decreases/holds constant and the cross-sectional area holds constant/decreases with the increase of the pressure, contributing to the decreasing/increasing tendency of the resistance in NCU/PCU. An electrode-configuration-based differential piezoresistive sensor made of conductive polymer composite is developed as an example to verify the aforementioned idea. The results show that the differential structure with the subunits made of identical ingredients can be realized by designing the electrode configurations and the “sensitivity”/“nonlinear error” can be improved/decreased.