Wide Band Research Articles

Simultaneous Achievement of Low Loss, Large Effective Mode Area and Wide Transmission Band Hollow-Core Anti-Resonant Optical Fibers

A novel nested structure of hollow-core anti-resonant optical fiber is proposed to achieve low loss, large effective mode area, and wide transmission band simultaneously in the near-infrared range of 1200–2200 nm. It is composed of six elliptical cladding tubes nested with six large circular cladding tubes, and six small circular cladding tubes are introduced in the gap of the elliptical tubes. The transmission characteristics of the hollow-core anti-resonant optical fiber are numerically investigated using the full-vector finite element method. The effects of structural parameters such as the cladding tube thickness and the tube diameters on the fiber transmission characteristics are analyzed in detail. The results indicate that within the wavelength range of 1200–2200 nm, the confinement loss remains below 0.017 dB/km, and the minimum confinement loss can be as low as 1.2 × 10−4 dB/km at 1500 nm. The effective mode area remains as large as ~1142.5 μm2. It should be noted that in the wide wavelength range of 1000 nm, the dispersion exhibits excellent characteristics ranging from 0.7 to 1.4 ps/(nm·km). Our fiber can find potential applications in ultra-long-distance and ultra-high-power transmission systems with a wide operating wavelength band.

Design and parametric analysis of FR4 based microstrip patch antenna for applications of wide band next generation networks

Abstract A simple rectangular microstrip patch antenna is designed, and its parametric analysis has been carried out by length variation of the ground using the concept of defected ground structure for wide band applications. A conventional rectangular slot is introduced into the patch to achieve the desired frequency band 3.57 GHz–9.10 GHz with resonating frequency at 7.9 GHz, impedance bandwidth of 87.29% and VSWR <2 primarily used for satellite communication within the X-band spectrum where uplink frequency from Earth to satellite falls in the range of 7.9 GHz to 8.4 GHz making it suitable for applications like fixed satellite services for next generation networks. The proposed antenna is designed with FR4 material as a substrate using HFSSv15. The complete dimension of the proposed antenna is only 21.3 × 18 × 1.5 mm3 only excited by a 50 Ω microstrip feedline. Performance of the fabricated antenna is experimentally validated and its Return Loss, VSWR, , Co and Cross Polarization, Radiation Pattern, Surface Current, Gain, Radiation efficiency are also observed.

Photoelectric properties of heterojunctions based on semiconducting metal oxides and indium selenide

The results of a comparison of the photosensitivity of heterojunctions based on InSe layered semiconductor and various wide band gap oxides (Mn2O3, CuFeO2, Fe2O3) produced by the spray pyrolysis method are given. The photoresponse of the heterojunction irradiated from the side of metal oxides was studied in the photon energy range of 1.2÷3 eV. The possibility of the formation of In2Se3 phase between of InSe and oxides and its effect on the photosensitivity of the heterostructures have been considered.

A compact quad-port slotted-spatula shaped ultra wide-band MIMO antenna for mm-Wave, 5G and beyond communications

ABSTRACT In this paper, we have proposed a slotted-spatula shaped four-port multiple-input multiple-output (MIMO) antenna for millimetre-wave (mm-wave), 5 G mobile communications and beyond. The proposed antenna is designed on Rogers RT/duroid 5870 substrate with an overall dimension of 3.21 λ 0 ×3.21 λ 0 ×0.025 λ 0 (30 mm × 30 mm × 0.7 mm) where λ 0 is the free space wavelength at the resonating frequency 32.16 GHz. Three inverted L-shaped slots and a rectangular slot are made on the patch which help in increasing the overall bandwidth. In addition to this, circular slots are made on the patch and ground which helps the antenna to resonate at 32.16 GHz. The proposed antenna achieves a wide bandwidth (BW) of 9.82 GHz (26.95 − 36.77 GHz) with an isolation of < −18 dB between the ports. Moreover, the proposed antenna achieves a peak gain of 4.69 dBi along with a high radiation efficiency of > 97% in the entire frequency band of interest. Moreover, in terms of diversity parameters, the presented antenna achieves acceptable values for envelope correlation coefficient < 0.0028, diversity gain < 9.96 dB, mean effective gain < −3 dB, total active reflection coefficient (TARC) < −10 dB, and branch power ratio (BPR) > −3 dB. To verify the results, a prototype is fabricated. The simulated and measured results are quite similar with a little mismatch. Thus, it can be concluded that our proposed antenna can be used for 5 G and mm-wave communications.

β-In2S3 Quantum dots embedded in Cation- Exchange Membrane for visible light driven photocatalytic microbial disinfection: Enhanced Ballast water treatment efficiency

Abstract This paper presents the visible-light driven photocatalytic disinfection of microorganisms in seawater using metal chalcogenide organic frame work. The microbial disinfection process which is induced by the photo-generation of reactive oxygen species does not produce any chemical by-products. Tetragonal β-In2S3 quantum dots (5 nm-10 nm) with orientation along [206] plane is embedded in perfluorinated cation exchange membrane (Nafion-117) through Grothuss mechanism. The synthesis conditions were optimized with an In/S ratio of 2/2, a reaction temperature of 70°C, and a reaction time of 2 hours. Nafion preserves the stability, integrity, and reusability of the quantum dots for up to three cycles, as confirmed by the absorption spectra of the films under seawater conditions (pH-8.02; TDS-27680 mg/l). The Raman active modes at Eg(ω3), A1, A1g,A1g (ω4) and F2g (ω5) symmetry correspond to the defect-spinel lattice of β-In2S3. With a wide band gap of 2.73 eV, β-In2S3 quantum dots has intense and broad photoluminescence at 446 nm, 465 nm, 500 nm, 542 nm and 655 nm corresponding to defect bands with energy in the visible region of the electromagnetic spectrum. The presence of sulfur and indium vacancies enhances the efficiency of the photocatalyst, by increasing the kinetics of the disinfection process (100 % disinfection within 90 minutes). The microbiological analysis of the sea water done via spread plate technique confirms complete disinfection from initial count of microbes: 4370 cfu/ ml in Zobell Marine Agar and 1910 cfu/ ml in Nutrient Agar. Further, the UV transmittance at 254 nm (65 %) reveals the aggregate of organic matter in untreated seawater which increases to 100 % upon treatment.&amp;#xD;

SYNTHESIS OF ZINC OXIDE/CHITOSAN/CHITRONELLA ESSENTIAL OIL HYBRID NANOPARTICLES USING SOL-GEL METHOD: STRUCTURAL AND OPTICAL PROPERTIES

Due to their properties, ZnO nanoparticles have recently been used as an additive material in active food packaging. ZnO has a wide band gap of about 3.37 eV, making it effectively used under UV light. However, ZnO nanoparticles are not effectively used under visible light. This study successfully synthesized ZnO-Chitosan-Citronella Essential Oil hybrid nanoparticles using sol-gel methods. Adding chitosan and citronella essential oil will affect nanoparticles' structural and optical properties. The structural, morphological, and optical properties of characterized hybrid nanoparticles were studied using X-ray diffraction (XRD) and FTIR, scanning electron microscope (SEM), energy dispersive X-ray (EDX), and UV-Vis spectroscopy. From XRD, it was obtained that the ZnO nanoparticles produced have a hexagonal wurtzite crystal structure with angles of 2q = 31.76°, 34.48°, 36.30° which are crystal planes with orientations (100), (002), and (101), as well as several other peaks for planes (102), (110), (103), (200) and (112) with a crystallinity index value of 86.5390%, and crystallite size of 8.87nm and 7.5335 nm. From FTIR Characterization, Zn=O functional groups were also obtained at wave numbers 657 and 475 cm-1. The morphology of ZnO nanoparticles from SEM spectroscopy shows a spherical shape with agglomeration, and the composition of the components Zn, O, and N elements is found, which come from chitosan materials. Furthermore, from the UV-Vis spectroscopy characterization, it was obtained that the absorption occurred in the 380-600 nm region with a band gap energy of 3.25 eV (using the tauc plot method), which was slightly different from the empirical results of 3.30 eV. The results show potential future studies of hybrid nanoparticles, such as additive materials in active food packaging.

Overview of Diamond Semiconductor Development and Research Directions

With the advancement of science and technology, traditional semiconductor materials can no longer meet the high frequency and high power demand. Diamond semiconductor has gradually become a research hotspot because of its excellent physical properties, such as high hardness and wide forbidden band. Through the literature review method, this paper discusses the crystal structure and physical properties of diamond semiconductor, such as high hardness, high thermal conductivity, wide bandwidth and other advantages. This paper also describes its preparation methods, including high temperature and high pressure synthesis and chemical vapor deposition, and discusses the current status of the application in the field of power electronics, optoelectronics, etc. The results reveal that the challenges faced by the doping process are complex, with high costs being a significant issue. However, with the development of technology and process optimization, diamond semiconductor is expected to become a hot spot in the research of high-frequency power.

MXene-Mediated Electronic State Engineering of Nickel Hydroxide for Efficient Piezo-Catalytic Hydrogen Peroxide Synthesis.

The piezo-catalytic synthesis of hydrogen peroxide (H2O2) offers a sustainable alternative to the traditional anthraquinone process by enhancing both the water oxidation reaction (WOR) and oxygen reduction reaction (ORR). However, conventional high-dielectric-constant piezoelectric materials, despite their superior piezoelectric responses, generally feature wide band gaps, low electrical conductivity, and a limited number of active sites─catalytically unfavorable characteristics that restrict their piezocatalytic efficiency. To address this, we developed a 2D Ni(OH)2-Ti3C2Tx MXene composite for efficient H2O2 production in pure water. The Ti3C2Tx MXene modifies the electronic states of Ni(OH)2, enhancing its deprotonation ability (Ni2+ to Ni3+) and creating hypervalent nickel active sites that boost H2O2 synthesis. Theoretical and experimental studies confirm that H2O2 generation occurs through combined WOR and ORR pathways, with ORR being dominant. The hierarchical 2D nanosheet structure facilitates crystal deformation under mechanical stress, amplifying the piezoelectric effect and reducing the energy input required for redox reactions. As a result, the Ni(OH)2-Ti3C2Tx composite achieves an impressive H2O2 yield of 351.1 μmol·g-1·h-1. This work provides a novel design strategy for high-performance piezo-catalysts in sustainable H2O2 production.

Electrophysical properties of demantoid and andradite garnets according to high-temperature impedance spectroscopy data: the influence of chemical and phase impurities (methodological aspects)

Object of the study and methods. Electrical characteristics of demantoid from clinopyroxenites (Poldnevskoye deposit, Middle Urals) and two samples of andradite 1-2 from skarns (Verkhniy Ufaley, Middle Urals; Sokolovsky mine, Rudny, Kazakhstan) were studied by impedance high-temperature spectroscopy in the heating-cooling mode at temperatures of 200–900 °C and frequencies of 1–106 Hz using of platinum and lanthanum-strontium cobaltite electrodes. Thermogravimetric, X-ray diffraction and diffuse light scattering data are presented. Results. Experimental chemical formulas of andradite 1-2 and demantoid are (Mg0.24Ca3.16Mn0.04)(Fe1.63Al0.33)Si2.95Ti0.05O12.14, (Ca3.49Mn0.04)(Fe1.79Al0.51)Si2.94Ti0.06O12.97, (Ca3.51Mn0.01) (Fe2.49Al0.05Cr0.0038)Si3.00O13.34, respectively. Andradite 1 contains up to ~20 % clinochlore impurity and an insignificant content of ferrobustamite impurity; in andradite 2 – no more than ~8 % of isostructural impurity of hydroandradite; demantoid does not contain phase impurities, while the peaks of the garnet phase are asymmetric due to the presence of two phases with the garnet structure. In the optical spectra of andradite 1-2, a wide band is observed in the near UV region and a significant number of sufficiently wide bands in the visible region associated with the absorption of Fe2+, Fe3+ and Ti4+ ions; Spectra of annealed samples of andradites at 750 °С are similar. For demantoid, a wide absorption band of 860 nm is observed, it shifts to 700 nm after annealing; it is assumed that the 860 nm band is associated with Cr2+ ions, which undergo additional oxidation during annealing. The Arrhenius dependences of the electrical conductivity of andradite 1 during heating and cooling differ from each other due to the presence of impurity phases (mainly clinochlore) in the sample. Dependencies for andradite 2 and demantoid in heating-cooling mode are close to each other, while the electrical conductivity of andradite 2 is higher than that of andradite 1. At temperatures of 750–775 °C, demantoid has the highest conductivity; while the Cr impurity does not make a significant contribution to its conductivity. Conclusions. Electrical characteristics of demantoid were obtained for the first time; Arrhenius dependences of two andradites of different chemical and phase composition were analyzed; it was shown that the composition has a significant effect on electrical conductivity. The obtained data can be used to construct geoelectric models of fragments of the earth's crust with the corresponding minerals.

Beam steering flexible transparent metasurfaces based on multi-bit phase gradient variations

In this study, a coded metasurface design employing the Pancharatnam–Berry (PB) phase principle was proposed, with precise beam steering achieved via phase gradient variations. The designed metasurfaces have the characteristics of flexibility and transparency. The metasurface unit uses a modified C structure to form dual-resonant points to form a wide frequency band, and the PB phase satisfy the relationship between the rotation angle of the element and the double difference of the reflected phase, by encoding metasurface arrays, functions such as reducing linearly polarized radar cross sections (RCS) and steering circularly polarized beams can be achieved. The array effectively reduces the linear polarization RCS in the 13–20 GHz band by rotating the phase difference between the unit metasurfaces. Under circularly polarized plane wave excitation, the metasurface unit achieves a high polarization conversion ratio (PCR) of approximately 0.9 within the 14–25 GHz frequency band. Experimental results show that the metasurface array achieves ± 50° wide-angle beam steering along both X- and Y-axes while maintaining 82% visible-light transmittance, providing potential applications in flexible electronics and reconfigurable intelligent surfaces (RIS).

Tightly coupled integration of visible light positioning, GNSS, and INS for indoor/outdoor transition areas

Tightly coupled integration of visible light positioning, GNSS, and INS for indoor/outdoor transition areas

First-principles investigation of the physical properties of wide band gap hexagonal AlPO4 compound for possible applications

First-principles investigation of the physical properties of wide band gap hexagonal AlPO4 compound for possible applications

On the nonlinear energy interactions in harmonically excited cantilever in the presence of friction

The influence of nonlinearities in mechanical oscillators is a crucial factor which affects their dynamic behavior and often leads to energy interactions and intricate responses. Among these nonlinearities, friction, particularly on the excitation side, can play a significant role by introducing complex energy interactions even in systems that would otherwise exhibit linear behavior. Understanding the effects of excitation-side friction is vital, as it can lead to challenges in control, unexpected energy transfer, and even structural failure if not adequately understood and addressed. Despite its importance, the effects of excitation-side friction on the dynamics of both linear and nonlinear oscillators remain seldom explored. This study aims to investigate the effects of excitation-side friction on a harmonically base-excited cantilever through a theoretical framework. A mathematical model is developed to analyze the system’s response. The investigation reveals nonlinear phenomena such as Localized Energy Transfer, Symmetric Mean-Switching Modulation, and Energy Dispersion. Localized Energy Transfer unveils how friction-driven energy interactions amplify energy at specific harmonics, which can be leveraged in vibration-based energy harvesting and damping applications. Symmetric Mean-Switching Modulation demonstrates a unique oscillatory behavior that resembles bistable systems. It offers insights into friction-driven modulation mechanisms relevant to precision control and sensing technologies. Energy Dispersion highlights the transition to wide band low energy vibratory responses possessing chaotic characteristics, which has implications for structural health monitoring of the engineering systems. Various plots from the theoretical analysis are utilized to examine these effects comprehensively. The findings provide new insights into friction-induced nonlinear energy interactions under harmonic excitation and enhance understanding of oscillator dynamics, offering valuable contributions to theoretical research and practical applications.

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on Wide Band Gap Semiconductors for Automotive Applications

Call for Papers for a Special Issue of IEEE Transactions on Electron Devices on Wide Band Gap Semiconductors for Automotive Applications

Pentagonal Shaped Fractal Band Notch Antenna using Parasitic Notch Filter

This paper presents the design of a band-notched simple iterative compact pentagonal fractal antenna. The antenna dimensions are W × L = 32 mm × 22 mm. The fractal radiating patch is placed on the front side of the FR 4 substrate material. The proposed fractal antenna geometry consists of a pentagon shape with three simple iterations of scale factor 0.62. The band-notched filter has been achieved by itching the pentagon shape as a parasitic patch on the back side of the substrate. The impedance bandwidth and reflection coefficient of the antenna are improved with the design of three iterations. The experimental results of the proposed CPW feed fractal antenna demonstrate wide band performance of 8.73 GHz ranging from 2.78 GHz to 11.51 GHz except the notched band frequency and exhibit peak gain of 8 dBi. The electromagnetically coupled pentagon parasitic patch is effectively optimized with respect to side length and position for notch-band development at 5.6 GHz, 9.3 GHz, and 12.5 GHz. These notch bands reject the interference of the 802.11a WLAN band and the lower spectrum of the X-band. The experimental radiation patterns are omnidirectional in the H-plane and bidirectional pattern in the E-plane. The proposed antenna is fabricated, and experimental results are verified on a vector network analyzer.

Nanomaterial ZnO Synthesis and Its Photocatalytic Applications: A Review.

Zinc oxide (ZnO), a cheap, abundant, biocompatible, and wide band gap semiconductor material with easy tunable morphologies and properties, makes it one of the mostly studied metal oxides in the area of materials science, physics, chemistry, biochemistry, and solid-state electronics. Its versatility, easy bandgap engineering with transitional and rare earth metals, as well as the diverse nanomorphology empower ZnO as a promising photocatalyst. The use of ZnO as a functional material is attracting increased attention both for academia and industry, especially under the current energy paradigm shift toward clean and renewable sources. Extensive work has been performed in recent years using ZnO as an active component for different photocatalytic applications. Therefore, a thorough and timely review of the process is necessary. The aim of this review is to provide a general summary of the current state of ZnO nanostructures, synthesis strategies, and modification approaches, with the main application focus on varied photocatalysis applications, serving as an introduction, a reference, and an inspiration for future research.

Wide band Single-mode optical fiber design for decreasing bending loss

Wide band Single-mode optical fiber design for decreasing bending loss

A tri-band (Ku, K and Ka-bands) shared-aperture reflect-transmit-array based on spatial phase genetic algorithm

Abstract A broadband tri-band shared-aperture reflect-transmit-array (RTA) is presented in this paper. This design is characterized by its simpler structure, tri-band operation and great broadband characteristics. In addition, the spatial phase genetic algorithm (SPGA) is also utilized to optimize the distribution of two kinds of elements to reduce the interference. Due to fmax / fmin &gt; 2.3, the hexagonal units are utilized. Two kinds of RTA elements are designed to achieve different reflection characteristics (Element Ⅰ: reflection in Ku-band; Element Ⅱ: reflection in Ka-band), and the same transmission performance in K-band. After array optimization using SPGA, this RTA was simulated, manufactured and measured to verify the performance. There is a good consistency between the simulated and measured results. The measurements indicate that the peak gain is 22.15 dBi, 25.09 dBic and 25.57 dBi at 16.5, 25.5 and 34.0 GHz, respectively. The 3 dB gain bandwidth (BW) is 18.93%, 39.12% and 19.80% in Ku-, K-, and Ka-bands, respectively. Furthermore, the 3 dB axial ratio (AR) BW is 31.58% when working at transmission mode. The proposed antenna is anticipated to exhibit considerable potential in multi-band application scenarios.&amp;#xD;

Research on characteristics of wide band filter based on composite resonators coupled with metal–insulator–metal waveguide

Research on characteristics of wide band filter based on composite resonators coupled with metal–insulator–metal waveguide

Co(acac)2-Mediated Regulation of Li2O2 Gradient Growth in Lithium-Oxygen Batteries.

In Li-O2 batteries, Li2O2 serves as the primary cathodic material but its wide band gap imparts insulating properties. Regulating the composition and morphology of Li2O2 enables the construction of a novel cathodic structure with exceptional electrochemical performance. Herein, we introduce an organic salt containing cobalt ions, cobalt acetylacetonate (Co(acac)2), into the cathodic electrolyte. We exploit its cation migration characteristics under an electric field to facilitate the generation and decomposition of Co-doped Li2O2, achieving gradient control and optimized growth of Li2O2. Moreover, the Co(acac)2 molecule stabilizes the properties of LiOx species and mitigates side reaction. In situ UV-vis and XANES spectra reveal direct interactions between Co(acac)2 and O2-/LiO2, highlighting the superior reversibility of Co(acac)2 enhanced Li-O2 batteries. Both experimental and theoretical results indicate that this novel Li-O2 battery system exhibits rapid reaction kinetics, with a reduced overpotential of 520 mV and extended cyclability, surpassing 400 cycles with lower polarization.