An original all-dielectric design that performs cloaking at terahertz frequencies is demonstrated. The cloak consists of
radially positioned discretized micrometer-sized cylindrical elements. Based on Mie theory and under adequate
excitation conditions (H along the rod axis), high-κ cylinders exhibit a strong magnetic resonance dependent on the
cylinder radii and material properties. Full-wave simulations coupled with a field-summation retrieval technique were
employed to adjust the electromagnetic response of individual ferroelectrics rods (Ba<sub>0.5</sub>Sr<sub>0.5</sub>TiO<sub>3</sub>; ε = 200 - tan δ = 2.10<sup>-2</sup>).
The rods magnetic plasma frequency was engineered such that the full cloak displays a progressive variation in its
permeability radial component; hence satisfying, for this polarization, the reduced equations derived from the conformal
transformation theory. The cloaking performance was assessed by modelling the complete micro-structured device.
Results unambiguously show that cloaking of any wavelength scaled objects located inside the cloak is achieved above
the Mie resonance frequency at 0.58 THz for the present device. In particular, the phase fronts of the electric field behind
the device are well reconstructed with a high value in transmission of the incident plane wave. This also means that the
absorption losses are small within the cloak in comparison with the metallic systems originally proposed. Although
cloaking is observed in a narrow band, this all-dielectric configuration provides an attractive route for designing cloaking
devices at microwave and terahertz frequencies.
Impedance matching in negative index 2D air hole array was addressed by the retrieval of the effective parameters. By
solving the eigenvalues problem, we first stress the major difference between an electromagnetic confinement in air for
the ground right handed branch and in the host matrix for the left handed one. We then calculate the complex
transmission and reflection coefficients for a finite slab from which the effective refractive index and impedance are
deduced by using a Fresnel inversion technique. The criterion n = -1 was found incompatible with the impedance
matching condition z = 1. Also, the relevance of the dispersion characteristics was assessed by a technique based on
spatial Fourier transform.