Ecoresorbable radio-frequency platform for humidity and temperature sensing

Abstract

Aiming at reducing electronic waste in sensing applications, we report on an eco-friendly printed microstrip line to sense relative humidity (RH) and temperature. The device is made of zinc resonators on paper used as transducers, which are coated with beeswax as encapsulant and using konjac as humidity sensitive coating. The multi-resonating structure, operating in the S-band, shows reproducible temperature and humidity sensing from 15 °C to 35 °C and 30% to 70% RH with sensitivities up to 1.9 MHz/°C and 2.0 MHz/%RH, respectively. This combination of transducing and sensing materials is promising for the realization of disposable environmental sensors.