相较于传统矿用甲烷传感器，超表面甲烷传感器在灵敏度、稳定性等方面具有较显著的优势，能够更好地满足矿井生产实际需要。针对现有金属太赫兹超表面传感器对折射率的灵敏度相对较低的问题，设计了一种基于连续域束缚态的太赫兹超表面甲烷传感器。超表面结构为金属−介质−金属3层结构，其中金属材料为金，介质材料为聚酰亚胺，上层金属结构为圆环，通过调节左侧开口大小改变结构的对称性，从而引起准连续域束缚态（QBIC）。分析结果表明，左侧开口间距为5 μm时调制深度最大，为95.69%。在超表面结构上覆盖1层甲烷气敏膜材料（cryptophane-A），得到甲烷传感器。选取5种体积分数的甲烷和5种环境折射率验证甲烷传感器检测性能，结果表明：金属太赫兹超表面传感器对折射率和甲烷体积分数的灵敏度分别为949 GHz/RIU和4.4 GHz/%，且折射率和甲烷体积分数与QBIC谐振峰的变化呈较好的线性关系。设计了一种方环金属超表面甲烷传感器，将其与圆环结构进行对比，发现圆环结构在Q因子、调制深度和灵敏度等方面均优异于方环结构。

Compared to traditional methane sensors used in mines, the metasurface methane sensor has significant advantages in sensitivity, stability, and other aspects, making it better suited to meet the practical needs of mine production. To address the issue of relatively low sensitivity to refractive index in existing metal terahertz metasurface sensors, a terahertz metasurface methane sensor based on bound states in the continuum was designed. The metasurface structure consisted of a three-layer configuration: metal dielectric metal (MDM), where the metal material was gold, and the dielectric material was polyimide. The upper metal structure was a circle, and by adjusting the size of the opening on the left side, the symmetry of the structure could be altered, which in turn induced quasi bound states in the continuum (QBIC). The analysis results showed that when the left-side opening gap was 5 μm, the modulation depth was maximal at 95.69%. A methane-sensitive membrane material (cryptophane-A) was then applied to the metasurface structure to form the methane sensor. Five different methane volume fractions and five environmental refractive indices were selected to validate the methane sensor's detection performance. The results showed that the sensitivity of the metal terahertz metasurface sensor to refractive index and methane volume fraction were 949 GHz/RIU and 4.4 GHz/%, respectively, and both the refractive index and methane volume fraction exhibited a good linear relationship with the QBIC resonance peak shift. A square ring metal metasurface methane sensor was designed and compared with the circular ring structure. It was found that the circular ring structure outperformed the square ring structure in terms of Q factor, modulation depth, and sensitivity.