A high precision and linearity differential capacitive sensor circuit dedicated to bioparticles detection

The authors presented in this paper an accurate and simple topology circuit dedicated to measure very small percentage of differential capacitance variations. The proposed circuit is based on a charge-based capacitance measurement method (CBCM). The simplified architecture and measurement linearity of the proposed circuit are the two main advantages required to satisfy the design criteria of capacitive sensors array intended for bio-particles detection. The presented simulation results give a minimum measurable differential capacitance of 7 aF in a linearity for 10 fF variation instead of a minimum level of 10 aF in 2 fF variation reported by very recent literature.