Theoretical results on the plane electromagnetic wave diffraction from a structure as a strip periodic grating on the paramagnetic layer, the permeability of which possesses negative real part in the microwave band, are obtained using analytical regularization based on the solution to the Riemann--Hilbert problem. The effect of the resonant transmission accompanied by extremely high absorption is thoroughly studied across the frequency band of the surface waves of the paramagnetic layer placed in the biasing magnetic field. This effect is caused by the surface waves of the layer, which are excited resonantly by the plane incident wave due to the presence of the grating. The resonant frequency can be electronically controlled by the biasing magnetic field.