Filtry
wszystkich: 1101
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: MICROWAVE/RF CIRCUIT
-
Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublikacjaConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
-
Electromagnetic Modeling of Microstrip Elements Aided with Artificial Neural Network
PublikacjaThe electromagnetic modeling principle aided withartificial neural network to designing the microwave widebandelements/networks prepared in microstrip technology is proposedin the paper. It is assumed that the complete information is knownfor the prototype design which is prepared on certain substratewith certain thickness and electric permittivity. The longitudinaland transversal dimensions of new design...
-
An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublikacjaAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...
-
Space-mapping-based design flow of miniaturized broadband matching transformer with perforated metallization
PublikacjaA fast design procedure of unconventional passive components has been presented and experimentally validated on the basis of a wideband microstrip four-section matching transformer (50:6 OHm). A classic impedance matching circuit has been miniaturized by means of compact microstrip resonant cells (CMRCs) leading to a considerable length reduction (34%) together with minor degradation in its performance. The spacemapping-based design...
-
Sensorless predictive control of three-phase parallel active filter
PublikacjaThe paper presents the control system of parallel active power filter (APF) with predictive reference current calculation and model based predictive current control. The novel estimator and predictor of grid emf is proposed for AC voltage sensorless operation of APF, regardless of distortion of this voltage. Proposed control system provides control of APF current with high precision and dynamics limited only by filter circuit parameters....
-
Model of noise sources in supercapacitors
PublikacjaThe paper presents detailed model of noise sources in supercapacitors. Noise phenomena observed in supercapacitors may be used as a diagnostic tool for assessment of supercapacitor quality or degradation mechanisms (e.g. corrosion of the electrodes or cloggin g up the pores) during ageing. Therefore, it is important to consider where noise is generated. The equivalent circuit of noise sources existing...
-
Left-handed propagation characteristics of a dielectric and metal-loaded periodic circular waveguide
PublikacjaIn this paper, a periodic dielectric/metallic rod is located in a circular waveguide to obtain left-handed operation. Two geometries of the dielectric/metallic rod are proposed and examined. The dispersion characteristics of the investigated waveguides are obtained using a surface impedance model. Moreover, equivalent circuit models are proposed allowing for calculation of the dispersion characteristics and scattering parameters...
-
A High-Efficient Low-Voltage Rectifier for CMOS Technology
PublikacjaA new configuration of rectifier suiting CMOS technology is presented. The rectifier consists of only two nchannel MOS transistors, two capacitors and two resistors; for this reason it is very favourable in manufacturing in CMOS technology. With these features the rectifier is easy to design and cheap in production. Despite its simplicity, the rectifier has relatively good characteristics, the voltage and power efficiency, and...
-
Samotestowanie toru analogowego ze wzmacniaczem w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrole-rami
PublikacjaPrzedstawiono nową metodę samotestowania toru analogowego opartego na wzmacniaczu w pełni różnicowym w elektronicznych systemach wbu-dowanych sterowanych mikrokontrolerami. Bazuje ona na nowej metodzie diagnostycznej opartej na przekształceniu transformującym próbki odpo-wiedzi czasowej badanej części analogowej na pobudzenie "ujemnym" impulsem prostokątnym na wejściu Vocm na krzywe identyfikacyjne w przestrzeni pomiarowej. Metoda...
-
Nonlinear secondary arc model use for evaluation of single pole auto-reclosing effectiveness
PublikacjaPurpose – The purpose of this paper is to discuss two evaluation methods of single pole autoreclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc implementation is presented. Design/methodology/approach – A computer simulation studies were...
-
Visual measurement system for chosen parameters of current collectors
PublikacjaA current collector is an element in a traction vehicle, used for movable, contact con-nection between the main circuit of this vehicle and the contact line. Bad technical condi-tion of these important elements in the main circuit of the vehicle result in its incorrect cooperation with contact line. Periodic control of technical condition of current collectors ensures infallible current collection. The pantograph diagnostics consists...
-
Hybrid P3HT: PCBM/GaN nanowire/Si cascade heterojunction for photovoltaic application
PublikacjaPoly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) are commonly used for the fabrication of organic photovoltaics (OPV). Efficiency limitations of OPVs could be circumvented by incorporation of inorganic nanostructures into organic blends. Again, integration of organic solar cells with well-developed silicon photovoltaic technology is ultimately desirable. In present work, GaN nanowires with diameters...
-
Low-Cost Automated Design of Compact Branch-Line Couplers
PublikacjaBranch-line couplers (BLCs) are important components of wireless communication systems. Conventional BLCs are often characterized by large footprints which make miniaturization an important prerequisite for their application in modern devices. State-of-the-art approaches to design of compact BLCs are largely based on the use of high-permittivity substrates and multi-layer topologies. Alternative methods involve replacement of transmission-line...
-
Bias-Dependent Dynamics of Degradation and Recovery in Perovskite Solar Cells
PublikacjaDegradation of perovskite solar cells (PSCs) is often found to be partially or fully reversible when the cells are allowed to recover in the dark. Unlike the dynamics of degradation, knowledge about the dynamics of PSC cell recovery is very limited. Here, we demonstrate that the PSC recovery strongly depends on the electrical bias conditions during the light-induced degradation and that it can be manipulated by applying an external...
-
Operational Enhancement of Numerical Weather Prediction with Data from Real-time Satellite Images
PublikacjaNumerical weather prediction (NWP) is a rapidly expanding field of science, which is related to meteorology, remote sensing and computer science. Authors present methods of enhancing WRF EMS (Weather Research and Forecast Environmental Modeling System) weather prediction system using data from satellites equipped with AMSU sensor (Advanced Microwave Sounding Unit). The data is acquired with Department of Geoinformatics’ ground...
-
Al-DIAMOND SCHOTTKY TUNNEL DIODES WITH BARRIER HEIGHT CONTROL
PublikacjaFew-nanometer-thick very highly boron-doped p-type layers were fabricated at metal-semiconductor interfaces of Schottky barrier diodes formed with aluminum on polycrystalline diamond. Preliminary results show that hermionically-assisted tunneling mechanism results in lower voltage drops at forward biasing of these diodes than expected for the Al-diamond metal-semiconductor potential barrier B. The effective barrier height Bpeff...
-
Piotr Płotka dr hab. inż.
OsobyPiotr Płotka otrzymał tytuł zawodowy magistra inżyniera w 1976 r., a stopień doktora w dyscyplinie elektronika w 1985 r. – nadane przez Wydział Elektroniki Telekomunikacji i Informatyki Politechniki Gdańskiej. W 2008 r. otrzymał stopień doktora habilitowanego, także w dyscyplinie elektronika, nadany przez Instytut Technologii Elektronowej w Warszawie. Od 1977 r. pracował w Akademii Techniczno-Rolniczej w Bydgoszczy, a od 1981...
-
Magnetic field mapping along a NV-rich nanodiamond-doped fiber
PublikacjaIntegration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows...
-
Design-Oriented Two-Stage Surrogate Modeling of Miniaturized Microstrip Circuits with Dimensionality Reduction
PublikacjaContemporary microwave design heavily relies on full-wave electromagnetic (EM) simulation tools. This is especially the case for miniaturized devices where EM cross-coupling effects cannot be adequately accounted for using equivalent network models. Unfortunately, EM analysis incurs considerable computational expenses, which becomes a bottleneck whenever multiple evaluations are required. Common simulation-based design tasks include...
-
Badania wytrzymałościowe zgrzein łączących pręty zbrojeniowe o średnicy Ø30mm
PublikacjaZakres badań dotyczy oceny wytrzymałościowej zgrzein doczołowych, wykonanych metodą zwarciową. Elementami zgrzewanymi były pręty zbrojeniowe o średnicy Ø30mm. Badania związane są z okresową kontrolą stabilności parametrów zgrzewarki, szczególnie w odniesieniu do górnych, dopuszczalnych przez producenta zakresów parametrów zgrzewania oraz analizą wyników i porównaniu rezultatów prób wytrzymałościowych uzyskanych w 2019 i 2020 w...
-
An Extended Control of the Input Angle for Matrix Converters Connected with the Non-Unity Power Factor Loads.
PublikacjaThis paper proposes a novel PWM modulation algorithm for Multiphase Conventional Matrix Converters (MCMC), with 3 inputs and k outputs, using the transfer function of the load angle. The proposed approach extends the range of power angle control at the input during the operation with a maximum voltage transfer ratio. The proposed concept is based on the Direct Analytic Voltage PWM (DAV--PWM) modulation with an elliptical trajectory...
-
Development of the sound field 3D intensity probe based on miniature microphones
PublikacjaThe engineered measuring probe uses three pairs of miniature microphones coupled. The signals from the microphones after an initial amplification are fed to differential circuits. Due to the required symmetry of the circuit it was necessary to select electronic components very carefully. Moreover, additional digital signal processing techniques were applied to avoid amplitude and phase mismatch. The view of the engineered probe...
-
Impedance monitoring of corrosion degradation of plasma electrolytic oxidation coatings (PEO) on magnesium alloy
PublikacjaImpedance technique based on continuous multisinusoidal current perturbation was used to explain degradation process of plasma electrolytic oxidation coatings (PEO) on magnesium alloy. An obtained impedance spectrum was fitted by electrical equivalent circuit to describe properties of conversion layer on magnesium alloy. Additionally, galvanostatic mode maintained during experiment, with DC current equal to zero, allowed to achieve...
-
The loop impedance measurement
Dane BadawczeThe loop impedance measurement
-
IFI16 Impacts Metabolic Reprogramming during Human Cytomegalovirus Infection
PublikacjaCellular lipid metabolism plays a pivotal role in human cytomegalovirus (HCMV) infection, as increased lipogenesis in HCMV-infected cells favors the envelopment of newly synthesized viral particles. As all cells are equipped with restriction factors (RFs) able to exert a protective effect against invading pathogens, we asked whether a similar defense mechanism would also be in place to preserve the metabolic compartment from HCMV...
-
Prediction of energy consumption and evaluation of affecting factors in a full-scale WWTP using a machine learning approach
PublikacjaTreatment of municipal wastewater to meet the stringent effluent quality standards is an energy-intensive process and the main contributor to the costs of wastewater treatment plants (WWTPs). Analysis and prediction of energy consumption (EC) are essential in designing and operating sustainable energy-saving WWTPs. In this study, the effect of wastewater, hydraulic, and climate-based parameters on the daily consumption of EC by...
-
Optoelectronic system for investigation of cvd diamond/DLC layers growth
PublikacjaDevelopment of the optoelectronic system for non-invasive monitoring of diamond/DLC (Diamond-Like-Carbon) thin films growth during μPA ECR CVD (Microwave Plasma Assisted Electron Cyclotron Resonance Chemical Vapour Deposition) process is described. The system uses multi-point Optical Emission Spectroscopy (OES) and long-working-distance Raman spectroscopy. Dissociation of H2 molecules, excitation and ionization of hydrogen atoms...
-
Nitrogen-doped diamond thin films: potential application in Fabry-Pérot interferometer
PublikacjaIn this paper we present results of preliminary research of using nitrogen-doped diamond (NDD) films as reflective layer in Fabry-Pérot interferometer. NDD films were deposited on Si substrates by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) with the use of CH4, H2 and N2 gas mixtures. During deposition process methane flow rate varied while nitrogen flow was constant. We performed series of measurements which showed...
-
Novel microstrip low-pass filters with fractal defected ground structures
PublikacjaIn this study, three microstrip low-pass filters (LPFs) containing fractal-shaped defected ground structures have been designed and manufactured. To improve the performance of microstrip LPF, cascades of inductively coupled fractal resonators have been applied. Simultaneously, to achieve relatively constant microstrip impedance resulting in essentially low reflection losses, a modification of the strip geometry has been introduced....
-
Improved selectivity compact band-stop filter with gosper fractal-shaped defected ground structures
PublikacjaA novel band-stop filter using Gosper fractal-shaped defected ground structures has been designed and manufactured. The improvement in the filter selectivity has been achieved by introducing a multiresonance fractal-shaped defect leading to a higher filter order, simultaneously maintaining its compact size. The experimental results prove the validity of proposed solution and its utility in novel miniaturized and severe requirement...
-
A compact microstrip rat-race coupler constituted by nonuniform transmission lines
PublikacjaIn this work, a step-by-step development of a compact microstrip rat-race coupler (RRC) has been presented and discussed. A high degree of miniaturization has been obtained by substituting six quarter-wavelength uniform atomic building blocks of a RRC by their nonuniform counterparts. The miniaturization procedure has been realized in three progressive steps: (i) the first layout solution of a miniaturized RRC has been acquired...
-
Application of the discrete Green's function-based antenna simulations for excitation of the total-field/scattered-field interface in the FDTD method
PublikacjaIn 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...
-
Simulation and experiment of radiating slot in a ground-plane of microstrip junction
PublikacjaW pracy przedstawiono badania numeryczne oraz eksperymentalne szczeliny promieniującej umieszczonej w płaszczyźnie masy złącza mikropaskowego. Złącze mikropaskowe składa się z linii mikropaskowej oraz rozwartego na końcu sęka. Szczelina umieszczona jest równolegle do linii mikropaskowej.
-
IFF/SSR rectangular patch antenna with reduced transversal size
PublikacjaW artykule przedstawiono antenę mikropaskową dla systemów IFF/SSR, zasilaną poprzez szczelinę typu H. Zastosowanie tego typu szczeliny pozwoliło na 36-procentową redukcję wymiaru poprzcznego anteny,co jest szczególnie istotne ze względu na potencjalne zastosowanie anteny w szykach.Pomierzone parametry eektryczne anteny to: VSWR < 1.5; stosunek polaryzacji ortogonalnej do właściwej < 30 dB w obu płaszczyznach;zysk > 7 dBi.
-
Novel topology of compact coplanar waveguide resonant cell low-pass filter
PublikacjaIn this study, a novel pseudoelliptic function low-pass filter (LPF) constituted by a compact coplanar waveguide resonant cell has been designed and manufactured. The lumped-element seven-pole prototype has been adequately realized by using complementary perturbations located both in signal line and ground plane metallization. The fabricated uniplanar LPF offers a compact size of 5.6 x 9.8 mm2, return loss better than 26 dB over...
-
Design of a broadband microstrip crossover for ultra-wideband applications
PublikacjaW pracy przedstawiono badania skrzyżowań linii mikropaskowych do zastosowań w systemach UWB. W procedurze projektowej wykorzystany został model zastępczy skrzyżowania. W celu poprawy parametrów skrzyżowań zaprojektowano dwie konfiguracje obwodów kompensujących. Wyniki numeryczne zweryfikowane zostały eksperymentalnie. Uzyskano dobrą zgodność pomiędzy rezultatami symulacji oraz pomiarów.
-
Slow-wave fractal-shaped compact microstrip resonant cell
PublikacjaA novel fractal-shaped compact microstrip resonant cell (CMRC) featuring a strong slow-wave effect has been presented. Its vital usefulness in the process of microstrip line miniaturisation has been proved and experimentally validated on the basis of a compact 3-dB branch-line coupler illustrating the possibilities of the approach. A prototype example structure has been designed to mirror the characteristics of a conventional device,...
-
Effect of ground plane size on radiation pattern in IFF/SSR microstrip antenna on thick substrate fed by H type slot
PublikacjaW pracy pokazano numeryczne i eksperymentalne wyniki badania wpływu rozmiarówmasy na charakterystyki promieniowania anteny dla zastosowań IFF/SSR, zrealizowanej na grubym podłożu i zasilanej przez szczelinę typu H. Pokazane wyniki dla anteny oryginalnej porównano z wynikami uzyskanymi po zmniejszeniu wymiarów masy (w każdym z kierunków). Pokazano jak dalece można zminimalizować wymiary anteny, przy założonym poziomie listków bocznych.
-
Electromagnetic wave scattering by a set of axially symmetric omega-medium cylinder
PublikacjaZaprezentowano analizę rozproszenia fali elektromagnetycznej od układu obiektów cylindrycznych zbudowanych z materiałów pseudochiralnych, umieszczonych w złączach falowodowych lub wolnej przestrzeni. Analiza bazuje na iteracyjnej procedurze rozproszenia i metodzie dopasowania rodzajów.
-
Radiation phenomena from pseudochiral cylinders at plane wave incidence
PublikacjaPrzedstawiono wpływ materiałów pseudochiralnych na charakterystyki rozproszenia fali elektromagnetycznej od obiektów cylindrycznych. W celu zbadania zjawisk rozproszenia zastosowano kombinacje iteracyjnej procedury rozproszenia i metodę dopasowania rodzajów. Wpływ zastosowania materiałów pseudochiralych w konfiguracjach obiektów cylindrycznych zaprezentowano na charakterystykach pola rozproszonego w strefie dalekiej oraz na charakterystykach...
-
A novel compact broadband 5-35GHz
PublikacjaW artykule przedstawiono zasadę pracy oraz procedurę projektowania zintegrowanego planarnego baluna (symetryzatora). Układ zaprojektowano wykorzystując połączenie linii paskowych i szczelinowych oraz struktury rezonatorów w formie wielogałęziowych sęków szczelinowych. Wykonany wielowarstwowy symetryzator pracuje poprawnie w zakresie 5-35GHz.
-
Compact-planar monopole loop antennas for 802.11b/g WLAN systems
PublikacjaZaproponowano planarne anteny monopolowe dla systemów komunikacji bezprzewodowej WLAN pracujących w pasmach 2.45GHz i 5.25GHz. W strukturze radiatorów zasilanych poprzez linię mikropaskową wykorzystano krzywe fraktalne: pętlę Kocha oraz pętlę Minkowskiego. W obu przypadkach uzyskano dwuzakresową pracę anten dzięki wprowadzeniu nowej konfiguracji zminiaturyzowanych transformatorów impedancji w układzie zasilania.
-
Investigations of the circulation effects in the structure using ferrite coupled slot-line section
PublikacjaW artykule przedstawiono badania cyrkulatora zrealizowanego w oparciu o magnesowaną wzdłużnie sekcję ferrytowych szczelinowych linii sprzężonych. Zaproponowane rozwiązanie pozwala na minimalizację rozmiarów układu cyrkulatora oraz na uzyskanie parametrów porównywalnych z dotychczas publikowanymi. W treści artykułu opisano kolejne etapy projektu. Wyniki numeryczne zweryfikowano eksperymentalnie. Pomierzony układ charakteryzował...
-
Microstrip line with short-circuited edge as a high-pass filter operating up to millimeter-wave frequencies
PublikacjaPrzedstawiono prosty planarny filtr górnoprzepustowy wykorzystujący linię mikropaskową ze zwartym brzegiem. Układy zaprojektowano w taki sposób, aby pasmo przepustowe rozpoczynało się w zakresie K lub Ka. Wykonano dwa prototypy: na podłożu w postaci warstwy dielektrycznej wykonanej z ceramiki alundowej oraz na podłożu organicznym o niskiej przenikalności elektrycznej. Wykazano dużą zgodność teoretycznych i pomierzonych charakterystyk...
-
Application of hybrid finite-difference mode-matching method to analysis of structures loaded with axially-symmetrical posts
PublikacjaW artykule przedstawiono nową metodę hybrydową do analizy układów falowodowych zawierających dowolne konfiguracje obiektów osiowo-symetrycznych. Metoda oparta jest na połączeniu metody różnic skończonych, metody dopasowania rodzajów oraz iteracyjnej procedury rozpraszania. W pracy przedstawiono badania zbieżności metody. Uzyskane wyniki numeryczne porównano z wynikami odniesienia. Duża zgodność wyników potwierdziła poprawność opracowanego...
-
Miniaturized uniplanar triple-band slot dipole antenna with folded radiator
PublikacjaA miniaturized uniplanar slot dipole for triple-frequency operation is presented. The antenna consists of a folded slot radiator with an increased number of degrees of freedom that allow for efficient size reduction. Rigorous electromagnetic (EM)-driven design optimization is applied in order to achieve the smallest possible size while maintaining acceptable levels of antenna reflection at the required operating frequencies. The...
-
EHV transmission lines wires location on line operation issues - case studies
PublikacjaTransmission lines towers construction affects the line parameters and influences on its operation in the future. Misguided design of the tower can lead to serious problems such as overvoltages, electric arc extinction difficulties, voltage asymmetry, resonance phenomena or increasing of magnetic field near the line. The paper points out those threats on example of 400 kV double circuit overhead transmission line with shunt reactors....
-
Displacement control in PWK-type pumps
PublikacjaThe most important, strategic goal however is creation of the variable displacement version of the new pump PWK. Thanks to full discharge of it's commutation mechanism from hydrostatic forces the variable pump can be directly controlled by low-energy actuator like proportional electromagnet or stepping motor. It means that costly and complicated hydraulic servomechanism (applied in all present variable displacement pumps) is no...
-
Residual current devices in electric vehicles charging installations
PublikacjaThe main requirements of national regulations and international standards regarding protection against electric shock in electric vehicle charging installations are presented. The principles of using residual current devices (RCDs) in such installations are discussed. It is pointed out that RCDs are mandatory equipment for safe charging of electric vehicles. It is noted that the standards require the use of RCDs having an appropriate...
-
Accurate electrothermal modelling of high frequency DC-DC converters with discrete IGBTs in PLECS software
PublikacjaIn the paper, a novel, improved method of the IGBT junction temperature computations in the PLECS simulation software is presented. The developed method aims at accuracy of the junction temperature computations in PLECS by utilising a more sophisticated model of transistor losses, and by taking into account variability of transistor thermal resistance as a function of its temperature. A detailed description of the proposed method,...