  The three-dimensional Gaussian beam transmission through a
ferrite-semiconductor finely-stratified structure being under an action of an
external static magnetic field in the Faraday geometry is considered. The beam
field is represented by an angular continuous spectrum of plane waves. In the
long-wavelength limit, the studied structure is described as a
gyroelectromagnetic medium defined by the effective permittivity and effective
permeability tensors. The investigations are carried out in the frequency band
where the real parts of the on-diagonal elements of both effective permittivity
and effective permeability tensors are close to zero while the off-diagonal
ones are non-zero. In this frequency band the studied structure is referred to
a gyrotropic-nihility medium. It is found out that a Gaussian beam keeps its
parameters unchanged (beam width and shape) when passing through the layer of
such a medium except of a portion of the absorbed energy.
