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A double slab with chiral structures based on three-segment cranks is analyzed for linearly polarized and normal incident waves. Both slabs are equal and are constituted by a two-dimensional lattice of four same-handedness metallic cranks. The slabs are parallel, with the unit cells perfectly aligned, and each layer is built on a standard FR4 board. Using a free-wave experimental setup and numerical simulations, the transmission and reflection coefficients were determined under normal incidence of linearly polarized waves. The retrieved values for the rotation angle, chirality parameter, refractive index, and ellipticity show a clear chiral behavior for a spacing lower than the slab width. It has also found that as the distance between the two layers increases, the resonant frequency also increases, and this dependence is close to exponential. Based on these observations, a system composed of two chiral slabs can be used as a tunable rotator or a polarization filter.

Producción Científica, This communication presents a novel diode switchable chiral metamaterial structure that manipulates the polarization in different ways depending on the active bias lines. Three different bias states that provide three totally different behaviors have been considered: polarization rotator, circular polarization converter and linear to circular converter., Ministerio de Economía, Industria y Competitividad (Project TEC2014-55463- C3-1-P, TEC2014-55463-C3-2-P and TEC2014-55463-C -3 - P)

The way the energy is absorbed when skin surface is being exposed to an electromagnetic radiation, and the physical consequences involved, are essentially the purposes of this study. In particular, we are dealing with high frequency radiation. When it is directed toward the surface of the skin, energy is transmitted to its inner layers causing an increase of the temperature. This process has experimentally been proved to be beneficial in many cases. Yet theoretically there is still a slightly hollow basis about it. This study pretends to deal with that subject from its origin, and allows future study doors to tap in depth this theme. Skin tissue is actually a multilayer tissue with a different tissue in each layer. Each one of them is characterized by some parameters, such as permittivity, conductivity, density and specific heat. Two kinds of skin tissues will be analysed: a fibrous and a fatty one, each of both with different skin humidity. In a former study some parameters such a possible non-linear temporal evolution of tissue temperature and a redistribution of heat through the tissues had been neglected for simplicity.

Numerical results obtained using a full-wave hybrid technique (comprising a new formulation of the coupled-mode method and the mode-matching method) for treating 3-D isotropic- chiral-material discontinuities in rectangular wave guides with perfect electrically conducting walls were compared with experimental data. For that purpose, samples of an isotropic chiral material were manufactured as composite materials. These samples were then fully characterized in the X-band. The measured constitutive parameters were used in the full-wave hybrid technique to predict the scattering parameters of three different structures-each a waveguide filled partially with the isotropic chiral material. The scattering parameters were also measured. The predicted and measured scattering parameters were in reasonably good agreement.

A chiral medium constituted by a two-dimensional lattice of eight cranks of the same handedness is studied and found that it exhibits a huge electromagnetic activity, circular dichroism, and negative refraction index. Using a free-wave experimental setup and numerical simulations, the transmission and reflection coefficients for a thin slab of such metamaterials were determined, and the effective values for the refractive index, electric permittivity, magnetic permeability, and chirality parameter were calculated. The obtained results by means of the simulation agree quite well with the ones calculated from the experimental measurements.

Isotropic chiral materials at microwave frequency are usually obtained by distributing, as random as possible, elements of chiral symmetry in a host medium. Here we propose a new manufacturing technique based on the precise location of same handedness cranks in a periodical configuration. By this method electromagnetic active media are produced with homogeneous, isotropic and reciprocal behavior for the microwave frequency range. These materials also present some fabrication advantages and new parameters for material design.

Materials with electromagnetic activity at microwave frequencies are usually made by spreading helical inclusions into a host medium. A new manufacturing technique of chiral media based on the inclusion of three segment wire hooks (cranks) is presented in this letter. We show that the random inclusion of many cranks into a host medium produces electromagnetically active materials. Based on a free-wave experimental system, we have found that the transmitted wave through the material is rotated with respect to the incident one. First results seem to be in agreement with the typical behavior of chiral media at the resonant frequency.