Humidity sensor devices using PEDOT:PSS

This paper discusses the use of PEDOT:PSS material for the implementation of two types of humidity sensor devices. The first device is a wireless humidity sensor that consists of a microstrip-fed rectangular slot antenna, loaded with one or two PEDOT:PSS blocks. The second device consists of a two port, filter, that consists of a split ring of rectangular shape, that is also loaded with a PEDOT:PSS block. PEDOT:PSS block was characterized with equivalent RC network, for three different humidity percentages, 40%, 70% and 100%. The three different RC value sets cause resonance frequency shifts in the response of the s parameter plots. The wireless sensor changes its radiating resonance and it can therefore be read by a distant interrogator, and the filter sensor presents a band pass zone shift that can be sensed with the integrated decision making system. Both sensor devices present high sensitivity, meaning that significant frequency shift and thus sensing ability is demonstrated even for small humidity variations response of the sensor devices.