Bi-hyperbolic and tetra-hyperbolic isofrequency topologies in a gyroelectromagnetic medium

Isofrequency topologies are studied for a gyroelectromagnetic medium obtained by stacking optically thin magnetized ferrite and semiconductor layers into a unified structure. In such a structure, both bi-hyperbolic and tetra-hyperbolic isofrequency contours appear as a simultaneous effect of both periodic arrangement of constitutive layers and external magnetic field influence. It is proposed to consider the obtained bi-hyperbolic and tetra-hyperbolic isofrequency contours as new topology classes of the wave dispersion.