The monograph presents the results of a numerical and analytical study of the processes of will scattering by various one-dimensional-periodic structures. In a wide range of changes in the frequency (up to quasi-optics) parameter, a large amount of information about the amplitude-phase characteristics of diffracted fields and the distribution of energy across spectra of various orders is presented. The general patterns of wave scattering and the specific properties of reflective and translucent lattices, combs, echelons, waveguide-type structures, tape and dielectric lattices, etc. are described. Particular attention is paid to physical phenomena in the resonant frequency region. For specialists in radiophysics, microwave engineering, acoustics.