为提高红外甲烷传感器的精度，对气室结构、电路和数据处理进行了优化设计。通过实验和光学仿真对红外气体传感器气室结构进行了重新优化设计，确定了最佳尺寸；采用三级差动放大电路设计滤除噪声；在数据处理的算法上，选用二次插值查表法来拟合方程处理数据等一系列举措设计出新的红外甲烷传感器。在甲烷浓度为0%~3%的体积分数段内对传感器进行随机测试，新传感器的反应时间能够控制在20 s以内,探测器灵敏度得到提高，测量误差控制在±0.04%。与国内外相似的产品相比，优化的传感器在高灵敏度、测量误差和反应时间上都达到了较高水平。

To improve the precision of the infrared sensor, the chamber structure, circuit and data processing was optimized. The chamber structure of the infrared gas sensor was redesigned and optimized by the experiments and optical simulation. Three differential amplifier circuits were chosen to eliminate the system's noise, and the secondary difference look-up table was used to process the data, and a new infrared methane sensor was designed by those measures. The experiments were performed to obtain the new sensor′s performance in the volume fraction 0%-3% of the methane. Results showed that the response time has been reduced to 20 s, the detection sensitivity was also improved, and the detection error was controlled within ±0.04%. After comparing the similar products at home and abroad, it is clear that this new designed sensor exhibits enhanced performances including higher detection sensitivity, lower detection error and shorter response time.