One side electrode type fluidic based capacitive pressure sensor

This paper presents the novel fluidic based capacitive pressure sensor. The electrical double layer capacitor (EDLC) concept was applied as a sensing method. The methanol was selected as an electrolyte due to its liquid properties such as low surface tension and dielectric permittivity. The circular membrane and microchannel were fabricated using PDMS material and the one side electrode was fabricated on the printed circuit board (PCB). PDMS was used as an insulator on the electrode to allow the formation of the ionic layer. The value of capacitance depends on the liquid movement inside the microchannel. The result of membrane deflections for PDMS membrane with dimension 2.8mm×2.8mm×1.5mm deviated compared to the simulation where it was assumed that the simulation model is was linear. From the experimental results, the operating frequency, response time and sensitivity of the sensor were 1.2 kHz, 0.21 s and 0.033 pF/kPa, respectively.