关键词: 气体传感器, 复合异质结, 微波检测, 丙酮

Abstract: To address the issue that traditional gas sensors require high-temperature heating for gas detection, a microwave sensor based on a helical structure is designed. This resonator can generate an independent transmission zero at a resonant frequency of 2.8 GHz, enabling the detection of target gases at room temperature. SnO₂/Co₃O₄ composite fibers are prepared via electrospinning and high-temperature calcination processes, and then integrated with the resonator to synthesize a novel microwave gas sensor. The sensor employs an N-P composite heterojunction, enabling high-precision detection of acetone within a volume concentration of 20 × 10^-6 to 120 × 10^-6. It offers advantages of simple operation, low cost, and miniaturization. Experimental results demonstrate that at room temperature, the SnO₂/Co₃O₄ composite fibers exhibit a response to volume concentration of 120×10^-6 acetone through variations in return loss, achieving a sensitivity of 32.8 × 10⁶ mdB. This study provides a new solution for low-concentration, high-precision gas detection in industrial and laboratory applications.

Key words: gas sensor, composite heterojunction, microwave detection, acetone