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 R2 of 0.9975, and acceptable linearity between 10–85% with R2 of 0.9779 with <10s response times.