Operation Temperature\nEffects on a Microwave Gas Sensor\nwith and without Sensitive Material

Microwave gas sensors have garnered attention for their\nhigh sensitivity\nand selectivity in the detection of volatile organic compounds (VOCs).\nHowever, traditional gas sensors generally rely on sensitive materials\nthat degrade over time and are easily affected by the environment,\ncompromising their stability and accuracy. This study proposes a microwave\nVOC gas sensor based on the condensation effect. The sensor adopts\na novel design without sensitive materials, utilizing the condensation\neffect to detect acetone gas. The sensor system consists of a microwave\nsensor and a temperature control device. As the sensor temperature\nis lowered below the boiling point of acetone, the condensation of\nacetone gas on the sensor surface is achieved, enabling accurate detection\nof acetone gas. Experimental results indicate that the accumulated\namount of acetone on the sensor surface is positively correlated with\nits response, with the maximum response of 3000 ppm acetone gas reaching\n0.34 dB. Additionally, this study investigated the detection mechanism\nof the sensor after adding the sensitive material MXene and compared\nthe performance of the sensor at different temperatures (−10\n°C, 0 °C, and 60 °C). The results show that at −10\n°C the sensor mainly captures acetone through physical adsorption,\nwhile at 25 and 60 °C, it primarily responds through chemical\nadsorption, with a maximum response of 0.29 dB. The VOC sensor based\non the condensation effect without sensitive materials not only achieves\nthe same sensitivity as traditional microwave sensors but also demonstrates\nstronger stability and anti-interference capabilities.