A Passive, Wireless Gas Sensor Based on Laser Induced Graphene for Soil Ammonia Level Monitoring

The excessive application of nitrogen fertilizer has damaged crops and the environment due to the production of ammonia. In this paper, a passive wireless gas sensor is proposed to realize real-time detection of ammonia in the soil. Patterned LIG, serving as the ammonia adsorber, is embedded in a passive inductor-capacitor (LC) radiofrequency (RF) tag. By wirelessly probing the reflection spectra of the LIG tag, the soil nitrogen levels may be detected with a sensitivity of 0.106dB/(gꞏm ⁻² ).