Abstract:Background. The article investigates diffraction of electromagnetic waves by n-sectional anisotropic diaphragm in a rectangular waveguide. Materials and methods. The author used the theory of boundary value problem for Maxwell's equations and the methods of linear algebra. Results. The researcher obtained an explicit formula of dependence of the coefficient transmission on the electromagnetic parameters. Conclusions. The developed recurrent formula allows determining the transmission coefficient of n-sectional anisotropic diaphragm in a rectangular waveguide; these results can be applied in nanotechnology, optics, and for composite materials investigation.