Fully printed parallel plate capacitance humidity sensors

Abstract

Printed humidity sensors on flexible substrates has potential to be low cost platform. A novel capacitance-humidity sensor was screen printed with silver electrodes and cellulose acetate butyrate (CAB) as the dielectric on flexible polyethylene terephthalate (PET) substrate. The parallel plate design achieves capacitance between 400-500pF at ambient conditions. This study found that the sensor exhibits superior linearity from 10-70%RH with R ² of 0.9975, and acceptable linearity between 10-85% with R ² of 0.9779 with <;10s response times.