Design of Polyimide-Coated Yagi-Uda Antennas for Monitoring the Relative Humidity Level

Coating an antenna with a hydrophilic polyimide film has been reported to enhance the effects of atmospheric relative humidity on the characteristics of the antenna. In this letter, we designed Yagi-Uda antennas with polyimide-coated dipoles, and we performed a simulation study investigating the influence of atmospheric relative humidity on their resonant frequencies. We conclude that antennas of this type might constitute viable sensors for the measurement of atmospheric relative humidity, and hypothesize that in certain situations such sensors may have advantages over existing alternatives.