基于严格的耦合波分析方法（RCWA）和等效媒质理论（EMT）研究了布儒斯特角入射时TM偏振光的导模共振特性以及不同结构参数对无标记光学检测灵敏度的影响。分析了三种不同膜层结构对检测灵敏度的影响，通过RCWA计算发现单层光栅在实验入射媒质范围内，折射率每改变0.1，共振角度位置平均变化5.1°，双层膜和三层膜光栅结构对应的共振角度位置平均变化3.6°和4.2°，均表现出了较高的检测灵敏度。在单层光栅结构中，随着光栅调制率由0.4525减弱至0.1441，折射率每改变0.1，角度变化率分别为4.48°和4.95°，检测灵敏度增加。

The characteristics of resonant guided-mode is analyzed under transverse magnetic (TM) polarization light at the Brewster angle using the rigorous coupled-wave analysis (RCWA) and effective media theory (EMT) and the effect of different structure parameters on label-free detection sensitivity is analyzed. The effect of three film structures on detection sensitivity is discussed. It is found that the shifts of resonant angles are 5.1°, 3.6°and 4.2° for single-layer resonant Brewster sensors (RBS), double-layer RBS and triple-layer RBS when the refractive index changes by 0.1, and all show high dectection sensitivities. As the modulation index reduces from 0.4525 to 0.1441 for single-layer RBS, the refractive index changes by 0.1, the changes of incident angles are 4.48° and 4.95°, and the detection sensitivity increases.