A Fully Inkjet-Printed Wireless and Chipless Sensor for CO2 and Temperature Detection

A study on a low-cost wireless fully inkjet-printed chipless sensor on a flexible laminate with three different inks is presented. It is based on two split ring resonator 90 degrees oriented between each other to allow for independent responses on two polarizations. A deposit of a polymer/single walled carbon nanotube composite ink is used to allow for the detection of CO2 as well as temperature. In this paper, it is shown that the inkjet printing of a polymer-based coating on top of the sensing/reactive deposit can significantly reduce the sensitivity to CO2, whereas the temperature sensitivity stays at same. Simulations and experimental results verify the repeatability of this topology.