设计了一种带金属挡板的直波导耦合方形腔组成的表面等离子体（SPPs）波导结构。利用有限元法分析了该结构的磁场分布、Fano共振特性以及传感特性。仿真结果表明，设计的SPPs波导结构可以形成2个Fano峰，且Fano峰的位置可以通过谐振腔的结构参数进行调节。此外，该SPPs波导结构可用于折射率传感，其最高折射率灵敏度和品质因数分别为2220 nm/RIU（折射率单元）和5542。最后，利用该结构对葡萄糖溶液中葡萄糖的质量浓度进行了检测，其灵敏度为0.264 nm/（g·L^-1）。所设计的SPPs波导结构在微纳传感领域有一定应用前景。

A surface plasmon polariton (SPP) waveguide structure composed of a straight waveguide with a metal baffle and square cavity is proposed. The magnetic field distribution, Fano resonance, and sensing characteristics are analyzed using the finite element method. The simulation results show that the SPP waveguide structure forms two Fano peaks, and the position of the Fano peaks can be adjusted using structural parameters. In addition, the SPP waveguide structure can be used for refractive index sensing. The maximum refractive index sensitivity and the figure of merit is 2220 nm/RIU (refractive index unit) and 5542, respectively. In glucose concentration detection, the sensitivity reaches 0.264 nm/(g·L^-1). The designed SPP waveguide may have potential applications in micro-nano-sensing fields.