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A square slot circularly polarized (CP) microstrip antenna with enhanced bandwidth is presented. The proposed antenna consists of a C-shape patch and four rectangular strips around the four corners on the lower ground, and is excited by a microstrip feedline. A broadband CP antenna can be achieved by adjusting the size of the strips. The measured results of -10 db impedance bandwidth is 157.2% (2-16...
A pattern control for portable devices at 2.45 GHz is proposed by exploiting phase-shifted characteristic modes (CMs). Among all available orthogonal CMs, the pattern control of a rectangular conductive plane has been obtained by a weighted linear superposition of only two current modes (J4 and J8). A proper position of two capacitive coupling exciters (CCEs), hosted above the rectangular conductive...
Computational electromagnetics often requires the creation of quadrature and cubature rules beyond those found in the literature. In many situations rules are required for the accurate evaluation of integrals containing singularities; examples include 1/R singularities and singularities in the basis functions used to represent current or charge density at sharp edges and corners. Techniques for synthesizing...
The characteristic mode (CM) theory has been widely recognized as a powerful tool for radiation/scattering analysis and optimization designs. As a natural extension of PEC CM theory and dielectric material CM theory, we propose a novel CM formulation for the systematic analysis of dielectric coated conducting bodies. The newly developed CM formulation bases on the EFIE-PMCHWT equation. Numerical cases...
This work presents applications for modeling electromagnetic scattering from two-dimensional cavities embedded in a perfectly conducting ground plane. First, the problem is discretized in time with Newmark's method, then solved using finite-element boundary-integral technique. This approach computes solutions in both cavities at the same time to strictly enforce coupled boundary conditions. Numerical...
We are interested in boundary integral formulations adapted to the solution of low frequency inductive electromagnetics in the case where the geometry is partitioned in (potentially irregular) subdomains. In the context of electromagnetics in piecewise homogeneous media, the multi-trace formalism (MTF) provides boundary integral formulations for Maxwell's equations posed at the interfaces between...
In conjugation with the method of moments, the Bayesian compressive sensing algorithm is utilized to fast analyze the monostatic electromagnetic scattering problem. Different from the orthogonal matching pursuit based compressive sensing approach that cannot determine the required measurement times, the proposed method overcomes the difficulty by adopting the Bayesian framework to recover the underlying...
Tracking PMCHWT-based characteristic modes (CMs) of dielectric or magnetic objects still remains a challenging task due to the presence of non-physical modes, but developing a robust tracking algorithm is essential to observe modal behavior over frequency. Thus, our efforts continue in enhancing an existing tracking algorithm which is based on eigencurrent correlation and far-zone eigenfield orthogonality...
Large finite periodic problems are suitable for the application of methods to achieve high acceleration rates in the solution process. Applying distributed macrobasis decomposition to compress the method of moments impedance matrix combined to slotFFT algorithm allow to cover larger structures closer to real cases.
The World Health Organization (WHO) has always asserted the importance of uniformity of regulatory frameworks that need to be based on scientific evidences to be effective. Differing regulatory frameworks across different countries are confusing and may feed incorrect risk perception. This work consists of an analysis of the scientific basis of European and non-European regulatory frameworks with...
In this paper a multiband MIMO antenna suitable for long term evolution (LTE) and wireless wide area network (WWAN) application is presented. The MIMO antenna consists of two symmetric antenna elements, neutralization line and modified ground plane printed on a printed circuit board (PCB). The size of each radiators are 15 × 25 × 4 mm3. To maintain the compactness, radiating elements are folded at...
In magnetic systems where small discrepancies of field map from the design value may strongly impact on the device performance, quality insurance procedures are foreseen to verify how each single coil meets the design criteria. External magnetic measurements can be used to estimate the possible deformations of conductors inside the magnet, but this implies inverse problem approaches. The measurement...
Lots of studies, some of them very recent, have demonstrated that a proper electromagnetic field exposure of seeds and sown can bring to an improvement of germination and growth indices. This phenomenon applied to agriculture can be extremely helpful in increasing raw materials productivity. The present work consist of an analysis of the scientific literature on the potential applications of ELF fields...
The transposition of European Directive 2013/35/EU into National regulatory frameworks introduced a series of new obligations for employers. Aim of this paper is acritical analysis of the new regulatory text in particular for what concerns exposure limits, new obligations and operative procedures in general.
In the paper, features of the brain microwave radiation measurements are considered. Influence of the contact pins addition on the antenna matching with head surface (changes of the reflection coefficient) is studied. Estimates of human head modelling with contact antenna-applicator are presented. Results of the investigations show that fluctuations of electromagnetic field in the near-field region...
Sodium Magnetic Resonance Imaging (MRI) is an attractive imaging technique for early detection of osteoarthritis, as sodium concentrations correlate with proteoglycan content. However sodium yields much less signal in human tissues compared to hydrogen: it has a very rapid transverse signal decay (T2) and rapid longitudinal relaxation (T1), low gyromagnetic ratio and much smaller concentration than...
Power delivery from an external source to implanted devices through wireless links is hindered by SAR regulations, which limit the amount of power radiated by an external source that reaches an implant. In order to increase the power delivered to the implant, we studied a solution with two transmitters and compared results with the common single transmitter link. HFSS and COMSOL have been used to...
In this work, the effect of the fabrication uncertainties on the substrate thickness on the radiation performance of the reflectarray antenna is addressed. An interval analysis (7A)-based method is used to compute the upper and lower bounds of the power pattern as a function of the deviations in the substrate thickness. The Minkowski Sum (MS) is exploited to combine interval phasors in order to mitigate...
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