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Search results for: DUAL BAND ANTENNA
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Application of the discrete Green's function-based antenna simulations for excitation of the total-field/scattered-field interface in the FDTD method
PublicationIn this article, the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method is proposed for simulation of wire antennas irradiating inhomogeneous dielectric scatterers. Surface equivalence theorem in the discrete domain is used to separate the problem into an inhomogeneous domain and a wire antenna that are simulated with the use of FDTD and DGF-FDTD, respectively. Then, the excitation of the...
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Fast multi-objective design optimization of microwave and antenna structures using data-driven surrogates and domain segmentation
PublicationPurpose Strategies and algorithms for expedited design optimization of microwave and antenna structures in multi-objective setup are investigated. Design/methodology/approach Formulation of the multi-objective design problem oriented towards execution of the population-based metaheuristic algorithm within the segmented search space is investigated. Described algorithmic framework exploit variable fidelity modeling, physics- and...
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Improved-Efficacy EM-Driven Optimization of Antenna Structures Using Adaptive Design Specifications and Variable-Resolution Models
PublicationOptimization-driven parameter tuning is an essential step in the design of antenna systems. Although in many cases it is still conducted through parametric studies, rigorous numerical methods become a necessity if truly optimum designs are sought for, and the problem intricacies (number of variables, multiple goals, constraints) make the interactive approaches insufficient. The two practical considerations of electromagnetic (EM)-driven...
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User Orientation Detection in Relation to Antenna Geometry in Ultra-Wideband Wireless Body Area Networks Using Deep Learning
PublicationIn this paper, the issue of detecting a user’s position in relation to the antenna geometry in ultra-wideband (UWB) off-body wireless body area network (WBAN) communication using deep learning methods is presented. To measure the impulse response of the channel, a measurement stand consisting of EVB1000 devices and DW1000 radio modules was developed and indoor static measurement scenarios were performed. It was proven that for...
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Michał Mrozowski prof. dr hab. inż.
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Recent advances in rapid multiobjective optimization of expensive simulation models in microwave and antenna engineering by Pareto front exploration
PublicationPractical engineering design problems are inherently multiobjective, that is, require simultaneous control of several (and often conflicting) criteria. In many situations, genuine multiobjective optimization is required to acquire comprehensive information about the system of interest. The most popular solution techniques are populationbased metaheuristics, however, they are not practical for handling expensive electromagnetic...
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UWB planar antenna dipole in the sandwich configuration
PublicationW pracy przedstawiono wyniki badań nad planarną anteną dipolową o ramionach kołowych, przeznaczoną dla systemu UWB. Ramiona dipola umieszczono pomiędzy dwoma warstwami dielektryka (konfiguracja kanapki) uzyskując redukcję wymiarów anteny. Stwierdzono, że impedancja wejściowa jest mniejsza, niż w przypadku pojedynczego podłoża, co umożliwia łatwiejsze dopasowanie anteny do toru zasilającego. Współczynnik odbicia w całym paśmie...
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Ridged horn antenna for ground penetrating radar
PublicationOmówiono modyfikację tuby grzbietowej polegającą na jej wypełnieniu dielektrykiem, w celu wykorzystania do układu pozwalającego na poszukiwanie obiektów znajdujących się pod ziemią. Omówiono badania, które doprowadziły do opracowania konstrukcji anteny z wypełnieniem dielektrycznym. Przedstawiono wyniki testu takiej anteny w układzie do detekcji obiektu metalowego umieszczonego pod ziemią.
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Sierpinski Monopole Antenna - Uniplanar Feeding Technique.
PublicationPrzedstawiono różne techniki zasilania monopolowych anten fraktalnych typu Sierpinskiego. Zaproponowano nowe sposoby zasilania: poprzez linię współosiową ze zmodyfikowaną rozszerzoną płaszczyzną masy oraz poprzez linię współosiową i falowód koplanarny. W obu przypadkach możliwa była znaczna miniaturyzacja struktury. Wykonane i przebadane prototypy anten potwierdziły przydatność przedstawionych rozwiązań.
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Microfluidically Frequency-Reconfigurable Self-Quadruplexing Antenna Based on Substrate Integrated Square-Cavity
PublicationIn this article, a novel concept of self-quadruplexing tunable antenna (SQTA) enabled by microfluidic channels is investigated. The operating channels are either filled with air or dielectric liquids to enable frequency tunability. The proposed SQTA is implemented on the substrate-integrated square-cavity (SISC). A swastika-shaped slot is milled on the top-surface of the SISC to create four quarter-mode resonators. The resonators...
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Miniaturized Metal-Mountable U-shaped Inductive-Coupling-Fed UHF RFID Tag Antenna with Defected Microstrip Surface
PublicationThis study presents a novel miniature ultra-high frequency (UHF) radio frequency identification (RFID) tag for metallic objects. Its arrangement includes a U-shaped feeder, which is inductively coupled to two E-type connected patches. Size reduction is achieved by means of utilizing the U-shaped feeder, and introducing a defection in the connection between the two E-type patches. The defection in the connection area between the...
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Energy-Saving Inertial Drive for Dual-Frequency Excitation of Vibrating Machines
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Zygmunt Krasiński jako człowiek dualny [Zygmunt Krasiński as a dual man]
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Dual-task exercise as a therapy for executive motor function in Parkinson’s disease
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Dual drive control under SVPWM, experimental results
Open Research DataThe dataset contains the experimental results of the project: A universal algorithm of space vector pulse width modulation for three-level three and multi-phase NPC inverters with DC-link voltage balancing. The analysis includes the behaviour of the drive system, examining the dynamic system response to speed and angle changes, and encompassing data...
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A low-band gap, nitrogen-modified titania visible-light photocatalyst
PublicationFotokatalizatory tlenku tytanu(IV) zmodyfikowanego azotem zostały zsyntetyzowane poprzez ogrzewanie wodorotlenku tytanu i mocznika w temperaturze 400ºC. Otrzymane fotokatalizatory charakteryzują się silną absorpcją w zakresie promieniowania widzialnego (400-500 nm) odznaczając się niskimi wartościami energii pasma wzbronionego (2,20 i 2,46 eV). Aktywność fotokatalityczną w świetle widzialnym potwierdzono przeprowadzając reakcję...
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PbGa2GeS6 crystal as a novel nonlinear optical material: Band structure aspects
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The optical properties and band gap energy of nanocrystalline La0.4Sr0.6TiO3 thin films
PublicationW pracy zbadano wpływ mikrostruktury na właściwości optyczne La0.4Sr0.6TiO3 przygotowanego w postaci cienkiego filmu. Gęsty film o grubości 200nm i wielkości krystalitów 14-30nm został przygotowany na szafirze.
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Band Gap Engineering toward Semimetallic Character of Quinone-Rich Polydopamine
PublicationSemiconductor|melanin interfaces have received increasingly more attention in the fields of photocatalysis and applied electrochemistry because of their facile synthesis, unique electrical properties, and strong capability toward photosensitization. In this work, we describe the electropolymerization of quinone-rich polydopamine (PDA) on the surface of hydrogenated TiO2 nanotubes with enhanced photoactivity in the visible spectrum....
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Low temperature broad band dielectric spectroscopy of multiferroic Bi6Fe2Ti3O18 ceramics
PublicationIn the present research the tool of broadband dielectric spectroscopy was utilized to characterize dielectric behavior of Bi6Fe2Ti3O18 (BFTO) Aurivillius-type multiferroic ceramics. Dielectric response of BFTO ceramics was studied in the frequency domain (Δν=0.1Hz – 10MHz) within the temperature range ΔT=-100°C – 200°C. The Kramers-Kronig data validation test was employed to validate the impedance data measurements and it was found...
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Shear band evolution phenomena in direct shear test modelled with DEM.
PublicationA direct shear test is widely used in the geotechnical engineering field. It is an easy and quick test to measure the shear properties of soil. This test often replaces more expensive and difficult tri-axial shear test. Despite that the direct shear test is known and used for a long time, it is still not well investigated at the grain scale. This paper deals with the micro behaviour of the cohesionless sand inside the direct shear...
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The forecasted values of cutting power for sawing on band sawing machines for Polish Scots pine wood (Pinus sylvestris L.) in a function of its provenance.
PublicationIn this paper the predicted values of cutting power for band sawing machine (EB 1800, f. EWD), which is used in the Polish sawmills, were showed. The values of cutting power were forecasted for Scots pine (Pinus sylvestris L.) wood of five provenances from Poland. These values were determined using an innovative method of predicting the cutting power, which takes into account of elements of fracture mechanics. The resulting predictions...
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Impacts of Using Exhaust Gas Recirculation and Various Amount of Dimethyl Ether Premixed Ratios on Combustion and Emissions on a Dual-Fuel Compression Ignition Engine
PublicationIn the presented research, the authors dealt with the specific properties of the combustion process of dimethyl ether (DME) in a combustion car (Volkswagen Golf IV) engine AJM 1.9 TDI PDE made by Volkswagen factory. Dimethyl ether is an alternative fuel produced most often from natural gas, which can be used in compression ignition engines as a single fuel or co-burned with diesel oil. This work describes the impacts of using exhaust...
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Single and Dual-GPU Generalized Sparse Eigenvalue Solvers for Finding a Few Low-Order Resonances of a Microwave Cavity Using the Finite-Element Method
PublicationThis paper presents two fast generalized eigenvalue solvers for sparse symmetric matrices that arise when electromagnetic cavity resonances are investigated using the higher-order finite element method (FEM). To find a few loworder resonances, the locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm with null-space deflation is applied. The computations are expedited by using one or two graphical processing...
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Overview of planar antenna loading metamaterials for gain performance enhancement: the two decades of progress
PublicationMetamaterials (MTMs) are artificially engineered materials with unique electromagnetic properties not occurring in natural materials. MTMs have gained considerable attention owing to their exotic electromagnetic characteristics such as negative permittivity and permeability, thereby a negative refraction index. These extraordinary properties enable many practical applications such as super-lenses, and cloaking technology, and are...
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Expedited Machine-Learning-Based Global Design Optimization of Antenna Systems Using Response Features and Multi-Fidelity EM Analysis
PublicationThe design of antenna systems poses a significant challenge due to stringent per-formance requirements dictated by contemporary applications and the high com-putational costs associated with models, particularly full-wave electromagnetic (EM) analysis. Presently, EM simulation plays a crucial role in all design phases, encompassing topology development, parametric studies, and the final adjustment of antenna dimensions. The latter...
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A Study of Mutual Coupling Suppression between Two Closely Spaced Planar Monopole Antenna Elements for 5G New Radio Massive MIMO System Applications
Publication5G NR (new radio) introduces the concept of massive MIMO (multiple-input-multiple-output) technology, in which a larger number of antenna arrays are installed on the transceiver. Due to the increased number of antenna elements allocated close to each other (approximately at half-wavelength distance), mutual coupling becomes a serious problem leading to performance degradation of the MIMO communication system. In this communication,...
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Fast Calibration-Free Single-Anchor Indoor Localization Based on Limited Number of ESPAR Antenna Radiation Patterns
Publication— In this article, we investigate how the calibrationfree single-anchor indoor localization algorithm developed for base stations equipped with electronically steerable parasitic array radiator (ESPAR) antennas can further be improved. By reducing the total number of ESPAR antenna radiation patterns used in localization process, one can significantly reduce the time needed for an object localization. Performed localization measurements...
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Expedited Re-Design of Multi-Band Passive Microwave Circuits Using Orthogonal Scaling Directions and Gradient-Based Tuning
PublicationGeometry scaling of microwave circuits is an essential but challenging task. In particular, the employment of a given passive structure in a different application area often requires re-adjustment of the operating frequencies/bands while maintaining top performance. Achieving this necessitates utilization of numerical optimization methods. Nonetheless, if the intended frequencies are distant from the ones at the starting point,...
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Reduced-Cost Two-Level Surrogate Antenna Modeling using Domain Confinement and Response Features
PublicationElectromagnetic (EM) simulation tools have become indispensable in the design of contemporary antennas. Still, the major setback of EM-driven design is the associated computational overhead. This is because a single full-wave simulation may take from dozens of seconds up to several hours, thus, the cost of solving design tasks that involve multiple EM analyses may turn unmanageable. This is where faster system representations (surrogates)...
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Design of UWB coplanar antenna with reduced ground plane
PublicationW artykule przedstawiono projekt kompaktowej anteny szerokopasmowej złożonej z dwóch kołowych pasków koplanarnych ograniczających szczelinę o podobnym kształcie. Antena zasilona była z 50 Ω linii trójpaskowej. Przeprowadzono badania wpływu zewnętrznego paska na pasmo anteny. Zaprojektowana antena została zbadana eksperymentalnie pokazując bardzo dobre parametry: w paśmie 1.7-15.5GHz uzyskano |S11| < −10dB. Antena charakteryzowała...
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Broadband Microstrip Patch Antenna with Reduced Transversal Size
PublicationW pracy przedstawiono propozycję anteny szerokopasmowej o ograniczonych wymiarach poprzecznych. Szerokopasmowość uzyskano poprzez stosowanie grubego podłoża i sprzężenia elektromagnetycznego poprzez dwie szczeliny sprzęgające. Wymiar poprzeczny łaty zredukowano poprzez zastosowanie szczeliny typu H. Antena została zaprojektowana i wykonana, zaś zmierzone pasmo wyniosło 29% dla WFS <1.5. Stwierdzono jednak, że charakterystyki...
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Inexpensive Helical Antenna for Global Navigation Satellite Systems
PublicationZaprezentowane zostały wyniki badań teoretycznych oraz eksperymentalnych niskobudżetowej anteny na pasmo L. Wyjściowa geometria struktury została obliczona na podstawie ogólnych wzorów. Efekt przesunięcia częstotliwości wywołany przez użycie rdzenia PU został również uwzględniony. Równolegle przeprowadzono badania wrażliwości parametrów anteny na proces produkcji. Zaprojektowano i wykonano układ dopasowania impedancyjnego. W paśmie...
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Double-ridged horn antenna with sinusoidal ridge profile
PublicationPrzedstawiono wyniki symulacji numerycznej oraz pomiarów parametrów anteny tubowej z podwójnym grzbietem. Badania numeryczne dotyczyły zarówno samego układu zasilania falowodu grzbietowego jak i całej anteny z uwzględnieniem sinusoidalnego profilu impedancji grzbietu. Wyniki obliczeń dopasowania oraz charakterystyk promieniowania, wykonanych przy użyciu symulatora QW-3D, porównano z wynikami pomiarów, stwierdzając dobrą zgodność...
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Compact CPW-fed Sierpinski fractal monopole antenna.
PublicationZaproponowano nową wielozakresową strukturę antenową dla zastosowań wielosystemowych. Jest to zminiaturyzowana antena monopolowa planarna, której obwód zaprojektowano wykorzystując czwartego rzędu iterację trójkąta Sierpińskiego ze współczynnikiem skali d=1.5. Antenę wykonano na podłożu dielektrycznym i zasilono wykorzystując falowód koplanarny. Badania parametrów wykonanego modelu potwierdziły wielozakresową pracę struktury.
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Dual fuelling of truck CI engine with diesel oil and mixture of propane and butane
PublicationW artykule przedstawiono zasadę działania dwupaliwowego zasilania jednocześnie olejem napędowym i odparowanym LPG silnika samochodu ciężarowego. Pokazano korzyści wynikające ze zużycia tańszego paliwa zbadane doświadczalnie.
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Reconfigurable Dual Active Bridge (DAB) Converter Topology for Aircraft Application System
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Enhanced Eye-Tracking Data: a Dual Sensor System for Smart Glasses Applications
PublicationA technique for the acquisition of an increased number of pupil positions, using a combined sensor consisting of a low-rate camera and a high-rate optical sensor, is presented in this paper. The additional data are provided by the optical movement-detection sensor mounted in close proximity to the eyeball. This proposed solution enables a significant increase in the number of registered fixation points and saccades and can be used...
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Vietnamese version of the Dual Filial Piety Scale: preliminary validation in a student sample
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Accelerated Gradient-Based Optimization of Antenna Structures Using Multi-Fidelity Simulations and Convergence-Based Model Management Scheme
PublicationThe importance of numerical optimization has been steadily growing in the design of contemporary antenna structures. The primary reason is the increasing complexity of antenna topologies, [ a typically large number of adjustable parameters that have to be simultaneously tuned. Design closure is no longer possible using traditional methods, including theoretical models or supervised parameter sweeping. To ensure reliability, optimization...
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Effective one-band Hamiltonian for the copper-oxygen plane in the superconducting copper oxides
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Electronic and optical properties of theMg2−xFexSiO4spinel: From band insulator to Mott insulator
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Dipolowe anteny planarne do zastosowań w standardzie Ultra-Wide band
PublicationW pracy dokonano przeglądu dipolowych anten planarnych projektowanych dla standardu UWB. Przedstawiono przykładowe promienniki oraz symetryzatory szerokopasmowe, które składają sie na antenę dipolową. porównano dopasowania anten dla wybranych kształtów promienników.
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Temperature effect on the emission spectra of narrow band Mn4+phosphors for application in LEDs
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Hydrogen-Containing Na3HTi1–xMnxF8 Narrow-Band Phosphor for Light-Emitting Diodes
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The Righi-Leduc effect: on evidence of two-band electronic structure in Nd1.86Ce0.14CuO4-y.
PublicationPrzedstawiono badania temperaturowe zależności oporu elektrycznego, efektu Halla (RH), przewodnictwa cieplnego (k) i współczynnika Righi-Leduc(SRL). Badania wykazały, że współczynnik RL> 0 w szerokim zakresie temperatur RH zmienia znak dwukrotnie w T=50 i 250K. Niezgodność znaków SRL i RH jednoznacznie wskazuje obecność w materiale nośników obu znaków tzn. n- i p- typu. W pracy pokazano, że transport ciepła zdominowany jest przez...
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Comparative analysis of three‐phase dual active bridge converter with different transformer topology and modern universal control for DC microgrids
PublicationThe presented work discusses issues related to the use of modern multiphase topologies of Dual Active Bridge (DAB)-type converters. Converters of this type are widely used in most DC microgrid applications. The introduction emphasizes a comparative analysis between single-phase and multi-phase DAB topologies within high-power DC microgrids, delving into their respective advantages, drawbacks, design procedures, and considerations...
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Dual role of oxygen-related defects in the luminescence kinetics of AlNMn2+
Open Research DataThis dataset presents the impact of temperature and pressure on AlN:Mn2+ luminescence kinetics. Unusual behavior of Mn2+ optical properties during UV excitation is observed, where a strong afterglow luminescence of Mn2+ occurs even at low temperatures. When the temperature increases, the contribution of the afterglow luminescence is further enhanced,...
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Linear antenna microwave chemical vapour deposition of diamond films on long-period fiber gratings for bio-sensing applications
PublicationThe growth processes of nanocrystalline diamond (NCD) thin films on fused silica optical fibers with UV-induced long-period gratings (LPGs) were investigated with regard to biosensing applications. The films were deposited using a linear antenna microwave plasma enhanced chemical vapor deposition system, which allows for the growth of diamond at temperatures below 350°C. The films exhibited a high refractive index n = 2.32, as...
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Sintering Parameter Investigation for Bimetallic Stainless Steel 316L/Inconel 718 Composite Printed by Dual-Nozzle Fused Deposition Modeling
PublicationFused deposition modeling (FDM) nowadays offers promising future applications for fabricating not only thermoplastic-based polymers but also composite PLA/Metal alloy materials, this capability bridges the need for metallic components in complex manufacturing processes. The research is to explore the manufacturability of multi-metal parts by printing green bodies of PLA/multi-metal objects, carrying these objects to the debinding...