理论提出并研究了一种基于矩形腔的窄带金属-介质-金属波导滤波器.建立滤波器内电场的传递矩阵模型，研究了矩形微腔与直通波导间耦合特性对器件滤波特性的影响.同时，研究了耦合长度、矩形微腔腔长、传输损耗等因素对滤波带宽的影响.研究结果表明，对于不同的矩形微腔腔长，存在一个可使器件滤波带宽达到最窄的耦合系数.此外，当微腔腔长越长且传输损耗越小时，滤波带宽也将越窄.该研究为表面等离子体波导的研究与设计提供了一定的参考.

A narrow-band Metal-Insulator-Metal (MIM) waveguide filter based on a rectangular cavity is proposed and investigated in theory. The influences of the coupling characteristics between the microcavity and the waveguide on the filtering characteristics, which have not been clearly demonstrated before, are studied by establishing a transfer matrix theoretical model for the transmission of electric fields in the filter. The effects of coupling length, rectangular cavity length, and propagation loss on the filtering bandwidth are also analyzed. It is found that for different resonance cavity lengths, there is an optimal coupling coefficient at which the filtering bandwidth is the narrowest. In addition, the greater the resonance cavity length and the lower the cavity loss, the narrower the filter bandwidth. These would provide some reference for the research and development of surface plasmon polariton filters.