Synthesis and Implementation (In STM8S) of Phased Circular Antenna Arrays Using Taguchi Method

This paper is aimed at assessing the effectiveness of the phase-only control strategy based on a customized Taguchi method when applied to Uniform Circular Arrays (UCA).  The objective of this paper consists to contribute the main lobe optimization of the smart antenna using Taguchi's method. We used the cited method in order to determine phase's weights for each element of the circular antenna array in order to steer the principal lobe from -65° to 65° covering all angular space. After that, we made an electronic platform using the microcontroller STM8S in order to implement an intelligent system. The architecture of this work had used a digital phase shifters, a demodulator AD8347, a modulator AD8349, an array antenna, cards STM8S-Discovery

Modeling of a compact, implantable, dual-band antenna for biomedical applications

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.The authors would like to thank Nicolas Corrao for his tremendous effortsthroughout the challenging fabrication process of the preliminary models at the HYPER platform,IMEP-LaHC, University of Grenoble Alpes. R. Silva would like to thank FCT for grant 2021.06819.BD.All individuals included in this section have consented to the acknowledgement

Improvement of Circularly Polarized Slot-Patch Antenna Parameters by Using Electromagnetic Band Gap Structures

Abstract This paper is devoted to the design of a novel Electromagnetic Band Gap (EBG) circularly polarized slot-patch antenna in multilayered configuration. The operating frequency band can be controlled via the disk radius and adjusting the slit lengths. An arrangement combining the circular slot-patch antenna design and feeding sources included are considered is necessary. Due to the exisiting of two feeding points, Position of both feeding points will permit Right-hand and Left-hand circular polarization operations. Thickness of substrate is chosen to reduce the spurious surface wave and width. The same technique will be used for the EBG cirlcularly polarized circular slot-patch antenna network and carry two benefits (such as improvement of bandwidth, beamforming, creating zero radiation beams) and filtering characteristics of the resonator (spatial filtering, increased directivity, misalignment) due to the resonant structure itself. The analysis provided will confirm successfully the various proposed structures and interest occupied by these types of antenna. Two approaches, one introduced by one layered Circularly-Polarized Patch-Slot antenna design with some changes in material configuration and the other produced by multilayered structures with different dielectric constants in the EBG resonator, are simultaneously used as key controllers of directivity enhancement

Impact of Composite Materials on the Shielding Effectiveness of Enclosures

International audienceThis paper investigates and compares the electromagnetic behavior of different shielding enclosures built with composite panels (dielectric materials with conducting inclusions, carbon-fiber, fiberglass, conductive materials). The numerical model is based on a full wave finite element method taking into account the geometrical details of the walls and avoiding the use of the classical equivalent layer approach. A 2D composite enclosure with two wall structures is modeled: fiber rods shielding and metal screen shielding. Impacts of conductivity and rod diameter on the shielding effect are investigated. Concerning metal screen, the shielding effectiveness is studied for different metals with the same mass, leading to identify the most effective metal. The influence of the angle of incidence and the number of apertures is also studied. Finally, a comparison is performed considering the same mass of the two composite wall structures, each composed of fiberglass and carbon fiber

Evaluation and comparison of Sentinel-2 MSI, Landsat 8 OLI, and EFFIS data for forest fires mapping. Illustrations from the summer 2017 fires in Tunisia

This study aims to assess the performance of the Sentinel-2 and Landsat 8 sensors to map forest fires. We choose two fire events, the Haddad fire and the Sidi Ferdjani fire, in northwestern Tunisia in 2017. Several spectral indices were derived from each sensor and the performance of each spectral index was assessed. A validation exercise was undertaken for each fire to compare the spatial matching between the burned area retrieved from each spectral index and its homologue obtained from the Emergency Management Service (EMS). Our results indicate that ΔNBR and its relativized version RBR derived from both sensors exhibit the highest discrimination power (M-statistic values >2.5). The Sentinel sensor is slightly more efficient than the Landsat 8 in mapping burned scars, but both sensors produce acceptable results. We conclude that both sensors could be a good alternative to EFFIS data, particularly when there is a need to detect details inside the burned areas

Prediction of Radiation from Shielding Enclosures using Equivalent 3D High Frequency Models

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Design of Frequency Reconfigurable PIFA Antenna With Floating Ground Plane

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