SnO2 capacitive sensor integrated with microstrip patch antenna for passive wireless detection of ethylene gas
A capacitive gas sensor using tin oxide (SnO2) nanoparticles has been integrated with a microstrip patch antenna for detecting ethylene gas emanated from climacteric fruits. The decrease in sensor capacitance owing to the presence of ethylene (0–100 ppm) changes the antenna resonant frequency and return loss (by 7 MHz and 9.5 dB) which can be monitored wirelessly.