A carbon nanotube/Fe₃O₄ thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe₃O₄ as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe₃O₄ based sensor performs well on sensing ammonia (NH₃) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor's performance for different NH₃ gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.
Keywords: NH3; carbon nanotube/Fe3O4 thin film; gas sensor; wireless passive.