Abstract-The mutual conversion of the TM mn and TE mn waves (m, n = 0) in periodic and aperiodic (fractal-like) stratified waveguide structures composed of dense metal-strip gratings is studied. The stopbands and passbands conditions of Bloch waves, the reflection and transmission spectra of the periodic structure are examined versus the gratings parameters. Peculiarities of the wave localization, selfsimilarity and scalability of both reflected and transmitted spectra of the fractal-like structure are investigated. The appearance of additional peak multiplets in stopbands is revealed and a correlation of their properties with the parameter of grating filling is established.