Anisotropic metamaterial with the ε-near-μ property in the entire angular domain enables broadband all-angle transmissions

Epsilon-near-mu metamaterials play a significant role in many fields such as radar, communication, and stealth technology, due to their ideal transmission responses. However, when electromagnetic (EM) waves illuminate such metamaterials at large angles, undesired reflectance occurs that greatly restricts the applications. Here, we propose a theoretical approach that can fundamentally eliminate the adverse effects of the incident angle on the transmission response of an anisotropic ε-near-μ material by adjusting the structural permittivity and permeability tensors. We take advantages of the nonresonance regions of electric and magnetic resonators so that the material parameters can attain the desired values in a wide frequency band. This allows us to design a nonreflective material with broadband all-angle transmissions from 0° to almost 90°, which is further verified by experiments with good performance. This work opens up a new route for the design of ultrawide-angle transmission-type metamaterials with high-efficiency and wideband properties, reaching significant applications in antenna radomes.

Homogenization of 3D metamaterial particle arrays for oblique propagation via a point-dipole analysis

A rigorous technique for the consistent calculation of the effective parameters of infinite three-dimensional metamaterial particle arrays in the realistic case of oblique wave propagation, is presented in this paper. The extracted polarizabilities of the consisting scatterer and the numerically retrieved wavenumber for the obliquely propagating electromagnetic waves are systematically inserted into a properly modified first-principles homogenization technique, thus leading to the characterization of the effective medium. Finally, the proposed methodology is applied to two popular, anisotropic metamaterial resonators.