On the design and characterisation of a microwave microstrip resonator for gas sensing applications

This study focuses on the microwave characterisation of a microstrip resonator aimed for gas sensing applications. The developed one-port resonator, consisting three concentric rings with central disk, is coupled to 50-Ohm feedline through small gap. A humidity layer deposited this gap by drop-coating an aqueous solution Ag@alpha-Fe<sub>2</sub>O<sub>3</sub> nanocomposite. operation principle sensor based change dielectric properties nanocomposite when relative varied. However, it should be underlined that, depending choice material, different target gases interest can detected proposed structure. frequency-dependent response obtained using reflection coefficient measured from 3.5 GHz 5.6 ranging 0 %rh 83 %rh. variation concentration strongly impacts two resonances in coefficient. In particular, increase level leads lowering both resonant frequencies, which used as parameters monitoring purpose. An exponential function has been accurately model frequencies humidity.