A PSE-Coated Interdigital Resonator Gas Sensor for Agricultural Applications

This paper presents a microwave gas sensor based on interdigital resonator structure coating with gas sensing material of poly (styrene-co-maleic acid) partial isobutyl/methyl mixed ester (PSE). This sensor was designed on the center of coplanar waveguide (CPW) to operate at 4 GHz with rejection characteristic. The measured results for five samples of ammonia hydroxide concentration (50, 200, 500, 1000, and 2000 ppm) under a static system in the closed chamber at room temperature were obtained. The levels of gas concentration can be impressively detected by measuring the transmission coefficient changes. The proposed sensor can be employed for several applications such as sensing the gas generating from agricultural products.