Transmissive properties of a wavelength-scale metal-dielectric planar structure are analyzed via numerical simulation by the method of single expression (MSE). Conditions of high transmittance in visible range are obtained for four-fold metal-dielectric (Ag-GaN) multilayer structure. For the critical points of transmittance spectrum corresponding electric field localization and power flow density distribution are presented. Dispersive properties of Ag layers are taken into account.