The dispersion relation for the electromagnetic wave-guided oscillations of a twodimensional (2D-) electron layer periodic array in a transversal magnetic field is analysed. Oscillation frequencies much lower than the electron cyclotron frequency exist under certain conditions. Additionally, the perpendicular propagation to the layers is investigated. It is demonstrated that a strong magnetic field causes a frequency shift and splitting, which are in inverse relation to the external magnetic field and the period of the layered electron system.