ABSTRACT
Similar to homogeneous metamaterials, random metamaterials are constructed by arranging subwavelength artificial “atoms” in certain lattices. However, for random metamaterials, one or more aspects (e.g., lattice size, geometry, orientation, and structural dimensions) related to their constituent “atoms” should vary instead of keeping constant in space,for the sake of achieving spatially random distribution of one or several effective EM parameters (e.g., permittivity, permeability, refractive index or wave impedance). Random metamaterials possess peculiar EM-wave-controlling features. Intuitively, they would guide or scatter EM waves irregularly due to their randomness and may find applications in diffuse reflection, radar stealth, etc. This chapter mainly focuses on two categories of random metamaterials capable of diffusing EM waves. These two kinds of random metamaterials possess randomly distributed gradients of refractive index and randomly distributed reflection phase, respectively. Typical implementation schemes for these two types of metamaterials are presented in Section 5.1, and Sections 5.2 and 5.3 will focus on their diffuse scattering behaviors with respect to impinging EM waves.
