By comparing the antenna-assisted transmission behavior of a rectangular aperture, the transmission enhancement corresponds to a Fabry-Perot-like resonance in the antenna-dielectric-metal cavity and the cutoff phenomenon can be understood as a result of the diffraction limit effect. 通过与纳米天线对矩形孔的透射影响的对比,揭示了透射增强现象对应于天线-电介质层-金属腔内的类法布里-珀罗共振,透射截止现象是由于衍射极限效应的限制。