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A two-dimensional (2-D) metasurface design for backward leaky wave suppression in microwave regime is proposed based on the theory of holography. The so-called Rabbit’s ears phenomenon describes that the backward mode in the reference wave plays the destructive role and makes the holography principle to behave properly mainly in an only narrow frequency interval. Here, we explore the utilization of the surface wave reflectors to suppress the backward mode to achieve wide-band holograms. Therefore, the reference wave form is manipulated by the choice of various reflector shapes and some providing forward mode dominant reference wave are analyzed and simulated. The less backward mode participates in the reference wave; the wider operation frequency range is obtained. With the canceled Rabbit’s ears phenomenon, variations in the reference wave frequency cause elevation angle scan. The results provide general insights into relation of the Rabbit’s ears phenomenon and the object wave accuracy in frequencies except the design frequency. The idea is also applied to multiple object wave holograms. The concept is verified using both electromagnetic full-wave simulations and experimental measurements.

Usage of multimodular donor–acceptor systems capable of revealing tunable ground- and excited-state properties is gaining momentous interest for applications in light energy harvesting and optoelec...

Emerging demands in sustainable energy and power conversion applications are calling for high frequency and high efficiency switching devices. Gallium nitride (GaN) as one type of wide band...

Fluorooxoborates have inspired investigations of deep-ultraviolet (DUV) nonlinear optical (NLO) materials that can meet the multiple criteria. Herein, five stable structures with the composition of BaB2 O3 F2 (I-V) are discovered using the ab initio evolutionary algorithm. Among them, BaB2 O3 F2 -I has been synthesized experimentally and confirms the reliability of the method. All of the predicted structures possess extremely wide band gaps (8.1-9.0 eV). Moreover, four new structures exhibit giant second harmonic generation (SHG) coefficients (>3×KDP, d36 =0.39 pm V-1 ). A novel type of the [BOF] layer with BO3 :BO3 F ratio of [1:1] is found in BaB2 O3 F2 -II and BaB2 O3 F2 -III. While BaB2 O3 F2 -IV and BaB2 O3 F2 -V are solely composed of the BO3 F group and have colossal SHG coefficients (ca. 4×KDP). It gives the direct evidence that the BO3 F group could generate strong SHG effect. Most importantly, the influences of BO3 :BO3 F ratio and their number density on band gap, birefringence and SHG effects are investigated.

In this article, the design, simulation, fabrication and measurement of an ultrathin and wide band radar metamaterial absorber (MMA) are introduced. The unit of the MMA consists of two different si...

A quenching–tempering–partitioning (Q–T–P) process was performed on a Fe-13Cr-3Ni-2Cu-0.1C alloy to investigate the effect of the partitioning process on the reversed austenite and mechanical properties. A quenching and tempering (Q–T) process was also carried out for comparison. The amount and characteristics of the reversed austenite were studied with XRD and TEM. The results showed that the volume fraction of reversed austenite in the Q–T–P-treated samples was higher than that in the Q–T-treated ones. Finer film-like and blocky austenite formed in the Q–T–P-treated samples, and fine Cu-rich precipitates were also well distributed in the matrix. However, wide band and blocky austenite formed in the Q–T-treated samples. Hence, the Q–T–P-treated samples had better comprehensive mechanical properties than the Q–T-treated ones.

In this work, we theoretically discuss the entropy change and the barocaloric effect in Y b I n C u 4 , which undergoes at ambient pressure a valence transition around 42 K. In order to carry out the calculations, we use a microscopic model consisting in a narrow band of 4 f electrons coupled with a wide band of conduction electrons. Our calculations show that the charge transfer between the bands, which explains the experimentally observed valence transition, produces large entropy change and consequently large caloric effect around the valence transition temperature. This new type of cooling process induced by the charge transfer mechanism opens up a horizon in this area of research and can be very important for solid state refrigerators technology.

A shorted magneto electric dipole with orthogonal dual polarization is designed for modern wireless communications. The proposed antenna is a wideband dual-polarized antenna consisting of magneto electric dipoles, which are fed by novel hook-shaped strip feeds. The antenna proposed in this paper is simulated using EM simulation software called high-frequency structure simulator. The simulated and measured results are presented. This antenna achieves 45.4% of impedance bandwidth of −10 dB RL for frequency range from 1.7 to 2.7 GHz. This frequency range covers the wireless communications applications like GSM 1800/1900, WCDMA, Bluetooth, Wi-Fi, etc.

A wide band log periodic millimeter‐wave antenna is proposed for 5G femtocells applications. This log periodic antenna consists of circular patches with radius kept up at a proportion of s...

In this paper, we demonstrate how a deep neural network (DNN) can be used to compensate for nonlinearities and distortion effects introduced by the latest technology of 5G transmitters. A linearization approach based on neural networks can successfully cope with the challenges introduced not only by the high nonlinearity, wide bandwidth, and high frequency but also with challenges due to inter-PA crosstalk and load modulation. The device-under-test used in this experiment, is a state-of-the-art 5G 4x4 active phased array (APA) operating in very highly nonlinear regions at 28 GHz with a 100 MHz wide 3GPPbasestationsignalandwithOTAmeasuredsignalsusedfor training. Using the proposed DNN based linearization technique, an improvement of 11 % in error vector magnitude (EVM) and 10 dB adjacent channel leakage ratio (ACLR) are achieved which demonstrates the promising potential of this technique for emerging broadband communication systems such as 5G/6G and low earth orbit (LEO) satellite networks

Purpose Recently, a novel cardiac imaging system based on a wide-band dielectric technology (KODEX-EPD) was introduced to guide catheter ablation. The aim of the study was to evaluate this 3D wide-band dielectric imaging system (WDIS) during cryoballoon (CB)-based atrial fibrillation (AF) ablation focusing on accuracy of pulmonary vein (PV)-anatomy. Methods In consecutive patients with symptomatic AF, CB-based ablation was performed in conjunction with the 3D WDIS. Selective PV-angiographies were performed, and 3D anatomy of the left atrium (LA) and PVs using the 3D WDIS was created. The ostial diameters of the ipsilateral right-sided and left-sided PVs and ostial diameters of the right-/left-sided upper/lower PVs demonstrated by selective angiographies were analyzed and compared to 3D WDIS-based PV visualization. Results In 65 patients (42/65 (65%) male, age 65 ± 9 years, 29/65 (45%) paroxysmal AF) a total of 260 PVs were identified. Median ostial PV-diameters for the ipsilateral left- and right-sided PVs were 38 [34; 43] and 37 [34; 40.3] mm when assessed fluoroscopically and 40 [35.7; 43] and 39 [35.0; 43] mm as demonstrated by 3D WDIS. There was no statistically significant difference between both methods regarding PV-diameter measurements. KODEX-EPD overestimated fluoroscopy measurements by 1.08 mm (95% limits of agreement of -1.93 mm and 4.1 mm). Conclusion The novel wide-band dielectric 3D-imaging system is feasible to create high-resolution images of cardiac structures during CB ablation procedures and accurately visualizes PV-anatomy.

National audience; La localisation d’objets connectés est un besoin avéré des personnes en situation de handicap (déficience visuelle et cognitive). Les technologies de localisation à moindre coût foisonnent et permettent de disposer d’informations de localisation précises. Dans cet article, nous rapportons le besoin des localisations d’objets dans le champ de l’autonomie des personnes en situation de handicap. Puis nous proposons un panorama des différentes technologies de localisation en proposant des critères pour les différencier. Un modèle et une implémentation de la Description Sémantique de la Position (DSP) d’un objet par une description spatiale (« le pilulier est sur la table dans la cuisine ») est décrit pour laquelle nous détaillons les algorithmes (localisation de la pièce, estimateur de proximité et position relative). Des premiers résultats obtenus à partir avec la plateforme LocURa4IoT présent sur la Maison Intelligente de Blagnac sont rapportés. Deux scénarios prospectifs viennent illustrer l’apport de la DSP dans l’assistance à la localisation d’un pilulier pour deux populations de déficience (visuelle et cognitive).

Article clarified the optimum fiber amplifiers length for wide band fiber system applications. Optical suppressed carrier transceiver with various fiber amplifier lengths in long haul applications is simulated by using optisystem simulation program version 13. Max. Q coefficient and min. BER can be tested for various fiber amplifiers lengths from 5 to 30 m. The optimum performance efficiency is achieved with 5 m amplifier length which the max. Q coefficient is 62.5 and bits error rate is tended to zero. Peak power amplitude level, noise signal power level, noise signal amplitude level (NSAL) and peak signal amplitude level after channel with a 45 km length for optimum fiber optic amplifier length of 5 m are measured.

In this paper, a novel compact bow-tie shaped microstrip patch antenna for wide-band application is presented. The proposed geometry consists of a modified bow-tie structure at the top of the Rogers RT-5880 substrate with a 50 Ω feed-line and 8 × 8 mm2 full ground plane. The diagonal slots inside the geometry have been implemented for exact resonating. The circuit analysis and various parametric analyses of the proposed geometry have been studied. The prototype of the antenna resonates at 27.77 GHz. The antenna has a fractional bandwidth of 6.77% (26.81–28.69 GHz) in simulation and 6.30% (26.89–28.64 GHz) in measurement respectively. The measured linear gain and radiation efficiency of the antenna are 7.00 dBi and 74% respectively. Also, it has a low sidelobe-level and cross-polarization level over the entire-space. The proposed wide-band antenna gives good time-domain characteristics as well as provides an acceptable FBR and impedance matching over the resonating band. All the properties suggest that the proposed antenna suits well for 5G communication along with various wireless systems.

We numerically show the applicability of standard 125 μm-cladding multi-core fiber (MCF) to long-haul and wide-band transmission in the S+C+L band. Although expanding the single-mode bandwidth is an effective way to increase the transmission capacity, the shortened cut-off wavelength degrades the XT and the Aeff. We numerically determine the optimum design of a four-core fiber with W-shape index profile considering the tradeoff relationship among the cut-off wavelength, Aeff, and XT. We show the design and applicability of a standard 125 μm-cladding MCF for S+C+L band transmission over long-haul distance of 1000 km and above with larger Aeff is possible from conventional single-mode fiber.

The objective of this paper is to describe a number of different techniques to enhance the out-of-band performance of wide-band rectangular waveguide filters. In particular, we discuss the use of mixed inductive and capacitive (hybrid) couplings, in conjunction with a staircase configuration and E-plane T-junctions, to yield a significant improvement both in the out-of-band response and in the filter selectivity. In addition to theory, we also discuss the performance of several filter prototypes, thereby fully validating the new filter topology.

Classifying CPs within the overly vague, uninformative category "suprasellar" prevents gaining any true insight regarding the risks associated with the surgical procedure employed. Routine MRI obtained with conventional T1- and T2-weighted sequences along the midsagittal and coronal trans-infundibular planes allow an accurate and reliable preoperative definition of CP topography. CPs developing primarily within the infundibulum and/or tuberal region of the hypothalamus, as well as those wholly located within the 3V, should be distinguished preoperatively from those lesions originally expanding beneath the 3V floor (3VF), the true suprasellar tumors. Among adult patients, about 40% of CPs correspond to infundibulo-tuberal tumors expanding primarily within the 3VF, above an intact pituitary gland and stalk. This subgroup of CPs shows strong adherences to the surrounding hypothalamus, as they are embedded within a wide band of reactive gliotic tissue, usually infiltrated by microscopic finger-like solid cords of tumor tissue. In elderly patients, a significant proportion of CPs correspond to papillary tumors developing above an intact 3VF, usually showing small pedicle-like or sessile-like attachments to the infundibulum. With the current diagnostic MRI workup routinely employed for CPs, it is possible, for the majority of lesions, to preoperatively differentiate these topographical variants and predict the type of CP-hypothalamus relationship that will be found during surgery.

In this article, a triple band-notched super-wideband (SWB) monopole antenna is designed and manufactured. The measured working frequency band (out of the filters working band) ranges from 2.5 to 20 GHz. A single radiating element is utilized to analyze and implement various MIMO antennas, with isolation between the antenna ports higher than 15 dB. Two parallel-fed elements SWB MIMO antenna and four parallel-fed elements SWB MIMO antennas are presented. Metallic barriers with different shapes are used to improve the isolation among ports from a low unacceptable value of 12 dB to a value higher than 20 dB within most of the working frequency band. S-parameters of the presented SWB MIMO antennas experimentally shows that antennas perform well up to 20 GHz, which is the highest frequency supported by the available Vector Network Analyzer used in the S parameters measurements. Satisfactory performance is observed up to 50 GHz by computer simulations using the CST software.

We have designed, optimized, fabricated and characterized highly reflective quasi-omnidirectional (angular range of $0-60^\circ$) multilayered structures with a wide spectral range. Two techniques, chirping (a continuous change in thicknesses) and stacking of Bragg-type sub-structures, have been used to enhance the reflectance with minimum thickness for a given pair of refractive indices. Numerical calculations were carried out employing the transfer matrix method and we optimized the design parameters to obtain maximal reflectance averaged over different spectral ranges for all angles. We fabricated some of the optimized structures with porous silicon dielectric multilayers with low refractive contrast and compared their measured optical properties with the calculations. Two chirped structures with thicknesses 21.6 $\mu$m and 60.4 $\mu$m, resulting in quasi omnidirectional mirrors with bandwidths of 360 nm and 1800 nm, centered at 1160 nm and 1925 nm respectively have been shown. In addition, we fabricated a stacked sub-Bragg mirror structure with a quasi omnidirectional bandwidth of 1800 nm (centered at 1850 nm) and a thickness of 41.5 $\mu$m, which is almost two third (in thickness) of the chirped structure. Thus, our techniques allowed us to obtain relatively thin quasi-omnidirectional mirrors with wide bands over different wavelength ranges. Our analysis techniques can be used for the optimization of the reflectance not only in multilayered PS systems with different refractive index contrasts but also for systems with other types of materials with low refractive index contrast. The present study could also be useful for obtaining omnidirectional dielectric mirrors in large spectral regions using different materials, flat focusing reflectors, thermal regulators, or, if defects are included, as filters or remote chemical/biosensors with a wide angular independent response., Comment: 11 p\'aginas

This paper establishes a coupled-mode theory (CMT) to help understand the inherent physics governing the transmission properties of a band-pass filter, based on which a two-layer metasurface exhibiting a wide band pass in Ka-band is designed. This method can be easily extended to other frequency regimes.

In this paper, low profile microstrip antenna has been presented for 5G and wideband communication applications. The proposed antenna is designed with FR-4 substrate with rectangular radiator, partial ground, and with modified feed position. The proposed antenna obtained 10 dB impedance bandwidth for a wide range of frequency from 2.9 to 10 GHz. The gain of antenna is changing from 2.2 to 4.4 dB, and radiation efficiency is having maximum value of 90%. This antenna can be applicable for 5G communication and specific UWB application.

In this article, we propose a novel equivalent circuit model that can accurately represent the wide‐band behavior of a defected ground structure with a slot that is positioned asymmetrically with respect to the signal transmission line and also with multiple slots. The inclusion of losses is crucial to guarantee a high level of accuracy. The number of circuit elements is very parsimonious, which makes the model efficient and the identification of the equivalent circuit parameters simple. Pertinent measurement and simulation results validate the proposed model in different cases.

SOXS (Son Of X-Shooter) will be the new medium resolution (R~4500 for 1'' slit), high-efficiency, wide band spectrograph for the ESO NTT at La Silla, optimized for classification and follow-up of transient events. SOXS will simultaneously cover UV optical and NIR bands (0.35-2.00 micron) using two different arms and a pre-slit Common Path feeding system. The instrument will be also equipped by a Calibration Unit and an Acquisition Camera (AC) System. In this paper we present the final opto-mechanical design for the AC System and we describe its development status. The project is currently in manufacturing and integration phases., 8 pages, 8 figures, SPIE conference. arXiv admin note: text overlap with arXiv:1809.01526

This work proposes wide band, circular polarized, slot antenna under the loading of of L shape resonators (frequency selective surfaces) for low radar cross-section applications. The proposed antenna has return loss bandwidth of 0.9 GHz and maximum gain of 4 dBi. The better reduction in RCS of 7dB is achieved.

This paper proposes an improved adaptive frequency sweeping method for electromagnetic simulation. A new convergence criteria of frequency sweep is defined. In addition, by combining matrix rational interpolation and dichotomy frequency sweep, the number of frequency points required for direct calculation is reduced compared with the traditional interpolation-based method. A numerical example is given to prove the effectiveness of the proposed method.