Self-standing printed humidity sensor with thermo-calibration and integrated heater

Abstract

In this work we report on a self-standing parallel-plate capacitive humidity sensor on a thin dry photoresist film with integrated resistive temperature sensor and heater on each electrode, respectively. The simple concept proposes dry photoresist film as substrate but also as dielectric humidity sensing layer. The characteristics of the temperature sensor (TCR ~900 ppmK-1), resistive heater (0.65 °C/mW) and humidity sensor (response time ~230 seconds, sensitivity ~23 fF / 1%R.H) were measured and are reported. FEM simulations were used to visualize the temperature distribution generated by the integrated heater.