  The visionary work of Veselago had inspired intensive research efforts over
the last decade, towards the realization of man-made structures with
unprecedented electromagnetic (EM) properties. These structures, known as
metamaterials, are typically periodic metallic-based resonant structures
demonstrating effective constitutive parameters beyond the possibilities of
natural material. For example they can exhibit optical magnetism or
simultaneously negative effective permeability and permittivity which implies
the existence of a negative refractive index. However, also periodic dielectric
and polar material, known as photonic crystals, can exhibit EM capabilities
beyond natural materials. This paper reviews the conditions and manifestations
of metamaterial capabilities of photonic crystal systems.
