We report on a negative-zero-positive metamaterial based on an omega-type microstructure with special attention on the nonvanishing group velocity for a zero refractive index. We first investigate the dispersion characteristics by full wave analysis, by stressing the necessary conditions of equality between the electric and magnetic plasma frequencies which are characteristic of the dispersion of the effective permittivity and permeability. Also, tuning of the gapless transition frequency between the left and right-handed dispersion branches was analyzed when the permittivity of the host substrate is changed. Last, we demonstrate experimentally the balanced composite character of the dispersion by frequency and angle-resolved transmission measurements, carried out at centimeter wavelengths on slabs and wedge-type prototypes, respectively.

The dielectric properties of a KTa_0.65Nb_0.35O₃ ferroelectric composition for a submicronic thin layer were measured in the microwave domain using different electromagnetic characterization methods. Complementary experimental techniques (broadband methods versus resonant techniques, waveguide versus transmission line) and complementary data processing procedures (quasi-static theoretical approaches versus full-wave analysis) were selected to investigate the best way to characterize ferroelectric thin films. The measured data obtained from the cylindrical resonant cavity method, the experimental method that showed the least sources of uncertainty, were taken as reference values for comparisons with results obtained using broadband techniques. The error analysis on the methods used is discussed with regard to the respective domains of validity for each method; this enabled us to identify the best experimental approach for obtaining an accurate determination of the microwave dielectric properties of ferroelectric thin layers.

Different implantable antenna designs exist to establish communication with implantable devices depending on the domain of use and the implantation space. Owing to their nature and purposes, these antennas have many imposed criteria on various characteristics, such as bandwidth, multiband behavior, radiation pattern, gain, and specific absorption rate (SAR). This presents a challenge when it comes to achieving satisfying results without a major compromise in any of these crucial parameters. Additionally, many of the existing designs do not follow a specific approach to obtain results. Measuring different parameters of such fabricated structures requires special conditions and special environments mimicking the tissues where they are supposed to be placed. For such issues, the use of biological or synthetic phantoms is widely employed to validate what is obtained in simulation, and a multitude of formulas exist for the creation of such phantoms, each with its advantages and drawbacks. In this paper, a miniature dual-band structure derived from the first iteration of the Koch fractal structure is designed to operate 2 mm below the skin in the arm of the human body, with the MICS (Medical Implant Communication System) and ISM (Industrial, Scientific, Medical) 2.4 GHz bands. The purposes of the design are to derive structures from commonly used shapes with certain behavior while maintaining miniaturization, and to easily design dual-band implantable antennas. More than one band is used to diversify uses, since bands such as the MICS band are mainly dedicated to telemetry. The structure is characterized not only by its low profile compared to various structures found in the literature with dimensions of 17.2 × 14.8 × 0.254 mm³, but also its ease of design, independent shifting of resonant frequencies, and the absence of the need for a matching circuit and a shorting pin (via) for miniaturization. It exhibits satisfying performance: bandwidths of 23 MHz in the MICS band and 190 and 70 MHz in the vicinity of the ISM 2.4 GHz band, and measured gain in the latter band of −18.66 and −17 dBi in the azimuth and elevation radiation patterns, respectively. To validate the antenna’s properties in a skin-mimicking environment, two simple phantom formulas found in the literature were explored and compared in order to identify the best option in terms of accuracy and ease of fabrication.

3D stacking technologies are electrically studied to predict high speed data transmission for memory on logic applications. Maximal frequency of bandwidth for memory-processor and processor-BGA channels are extracted and compared for Face to Face and Face to Back 3D stacking and between an interposer technology. Using expected electrical specifications of Wide IO applications in terms of data rates, a roadmap is proposed in accordance to the integration density, carried out by the TSV density.

The tuning of the dispersion characteristics of a balanced composite right- and left-handed transmission lines is demonstrated at centimeter and millimeter wavelengths. To this aim, coplanar waveguides, periodically loaded by interdigitated capacitances and stublike inductances, were fabricated onto a ${\text{Ba}}_{0.5}{\text{Sr}}_{0.5}{\text{TiO}}_3$ ferroelectric thin film. The scattering parameter measurements show that the lines are left handed from 8 to 18 GHz and right handed above. The results are interpreted by the retrieval of the effective permittivity and permeability, which exhibit Drude-like dispersion characteristics with a magnetic plasma frequency, which can be tuned via the voltage-controlled permittivity variation in the BST thin film.

We report on the theoretical and experimental analysis of Omega-type metamaterials operating in X and Ku-bands. The prototypes are fabricated on the basis of metal waveguide technologies (hollow and TEM parallel plate) loaded with printed boards of interconnected Omega-shaped motifs. This interconnection of particles in the transverse direction leads to a broad left-handed band. Moreover, it is shown that such structures can be designed for a continuous negative-zero-positive index dispersion. This balanced composite behavior, so far known for periodically loaded transmission lines is verified experimentally with left- and right-handed dispersion branches extending from 8 to 12 and 12 to 16 GHz respectively. This zero-gap capability is explained on the basis of effective parameters retrieval.