An oscillator-based capacitive proximity sensor is presented. To improve the sensor's sensitivity by minimising the effect of parasitic capacitance, the proposed sensor employs a negative capacitance generation technique. The sensor is implemented with a standard 0.18m CMOS technology, and the measurement results show that frequency variation is about 1.4% at 5cm distance while only consuming an 85A current. The die area occupies 520 by 280m, and the size of an external sensing plate is 0.5 by 0.5cm.
ASJC Scopus subject areas
- Electrical and Electronic Engineering