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Search results for: BROADBAND
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Ultra-broadband photonic internet
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Broadband Sonar with a Cylindrical Antenna
PublicationSkutkiem wzrostu szerokości widma sygnałów w sonarach z płaskimi antenami jest wzrost szerokości odchylanych wiązek, jeżeli beamformer dokonuje kompensacji faz tylko na częstotliwości środkowej widma. W artykule przedstawiono wyniki obliczeń, które odpowiadają na pytanie, czy podobny efekt występuje w szerokopasmowych sonarach z anteną cylindryczną. Obliczenia przeprowadzono dla anten nadawczych o szerokich wiązkach i anten odbiorczych...
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Broadband interference in speech reinforcement systems
PublicationArtykuł podejmuje niedoceniany problem wpływu liczby i rozkładu głośników w systemach nagłośnienia, na jakość przekazu głosowego, czyli na zrozumiałość mowy w audytoriach. Superpozycji przesuniętych w czasie szerokopasmowych sygnałów o tym samym kształcie i lekko różnych wielkościach, które docierają do słuchacza z licznych spójnych źródeł, towarzyszy zjawisko interferencji prowadzące do głębokiej modyfikacji odbieranych sygnałów...
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A novel compact broadband 5-35GHz
PublicationW 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.
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Investigations of broadband multilayered coupled line couplers
PublicationW pracy przedstawiono dwa układy szerokopasmowych sprzęgaczy 3dB. Pierwszy układ zrealizowany jest w oparciu o linie paskowe z rowkowanym ekranem. Drugi układ to zmodyfikowany układ sprzęgacza mikrofalowego zrealizowanego w oparciu o linie mikropaskowe ze wspólną masą. Zaproponowane układy sprzęgaczy odznaczają się szerszym pasmem pracy w porównaniu do układów prezentowanych w literaturze. Wyniki symulacji układów zostały zweryfikowane...
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Broadband Buses Based On Multicore Optical Fibres
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On the broadband behaviour of planar elliptical dipole-modal approach
PublicationBroadband behavior of planar elliptical dipole structure is analyzed using Illuminatin Modes (IM) approach. The current on patch has been expanded in series of eigenfunctions in form of Mathieu radial and angular functions. The frequency behavior of current distributions and related powers have been discussed to explain the mechanism of broadband operation of the dipole. Different behavior of radiations patterns in wide frequency...
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Ultrawideband transmission in physical channels: a broadband interference view
PublicationThe superposition of multipath components (MPC) of an emitted wave, formed by reflections from limiting surfaces and obstacles in the propagation area, strongly affects communication signals. In the case of modern wideband systems, the effect should be seen as a broadband counterpart of classical interference which is the cause of fading in narrowband systems. This paper shows that in wideband communications, the time- and frequency-domain...
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Global Miniaturization of Broadband Antennas by Prescreening and Machine Learning
PublicationThe development of contemporary electronic components, particularly antennas, places significant emphasis on miniaturization. This trend is driven by the emergence of technologies such as mobile communications, the internet of things, radio-frequency identification, and implantable devices. The need for small size is accompanied by heightened demands on electrical and field properties, posing a considerable challenge for antenna...
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Tunable broadband integrated circuits for adaptive optical interconnects
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Design of a broadband microstrip crossover for ultra-wideband applications
PublicationW 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.
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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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Search for Ultimate Throughput in Ultra-Broadband Photonic Internet
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Detection of broadband signals in the field of aperture and array systems.
PublicationAnteny i szyki anten w dolnopasmowych systemach hydroakustycznych wnoszą istotne zniekształcenia liniowe wpływające na możliwości detekcji sygnałów szerokopasmowych. W artykule analizowany jest charakter takich zniekształceń metodą przestrzenno - czasowych odpowiedzi impulsowych. Sygnał odbierany w różnych kierunkach przestrzeni poddano filtracji na dwa sposoby z filtrem dopasowanym do sygnału nadawanego i filtrem dopasowanym...
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Routing decisions independent of queuing delays in broadband leo networks
PublicationThis paper presents an analysis of queuing and propagation delays of Inter-Satellite Links (ISLs) in broadband Low-Earth Orbit (LEO) satellite networks. It is shown that queuing delays are negligible in all reasonable working conditions of the broadband ISL network. This fact makes it possible to simplify the routing protocols in such networks and permits using already known multi-commodity flow solutions for routing. The performance...
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Novel doubly perforated broadband microstrip branch-line couplers
PublicationTwo broadband compact doubly perforated hybrid couplers have been designed, manufactured, and measured. To improve frequency characteristics and to reduce circuit dimensions, two kinds of perforations have been introduced: the defected ground structures in the ground plane metallization and photonic bandgap cells in the strip metallization. Measurement results show essential miniaturization (~39% and ~36%) and enhancement of the...
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Non-Satellite Broadband Maritime Communications for e-Navigation Services
PublicationThe development of broadband network access technologies available to users on land has triggered a rapid expansion of a diverse range of services provided by terrestrial networks. However, due to limitations of digital communication technologies in the off-shore area, the maritime ICT systems evolution so far has not followed that trend. Despite the e-navigation initiative defining the set of Maritime Services, the progress in...
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Reference LED source of subnanosecond pulses of broadband optical radiation
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Active optical fibres for application in laser and broadband ASE sources
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Compact broadband multi-way 1:6 power divider
PublicationThis paper introduces a design flow of a microstrip multi-way 1:6 power divider incorporating photonic bandgap (PBG) structures. Themethod proposed has enabled the achievement of considerable miniaturization (15%) together with transmission characteristics enhancement(141% bandwidth). Measured results show significant similarity to theoretical characteristics, which proves the attractiveness of presented design methodology.
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Modulation and multiplexing in ultra-broadband photonic internet: Part I
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Modulation and multiplexing in ultra-broadband photonic internet: Part II
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Analysis of beam sharpening effectiveness in broadband radar on inland waters
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Modeling of broadband light source to use with optical coherenttomography system
PublicationW pracy przedstawiono modelowanie źródeł szerokopasmowych na potrzeby systemów koherentnej tomografii optycznej z punktu widzenia uzyskiwanej zdolności podłużnej i jakości otrzymywanych obrazów. Pokazano na przykładzie źródła szerokopasmowego wykorzystującego światłowód fotoniczny do generacji w wyniku zjawisk nieliniowych ''supercontinuum'' wpływ kształtowania wiązki na możliwości pomiarowe systemu OCT.
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A Broadband Circularly Polarized Wide-Slot Antenna with a Miniaturized Footprint
PublicationThis letter presents a novel and simple feeding technique for exciting orthogonal components in a wide-slot antenna. In this technique, a rectangular bracket-shape parasitic strip is placed at the open end of the straight microstrip line to excite the fundamental horizontal and vertical components of the circular polarization (CP). The proposed technique—when employed in conjunction with the asymmetrical geometry of coplanar waveguide...
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state aid for broadband infrastructure
Open Research DataThe dataset encompasses a choice of important legal acts, a list of selected bibliography, and a list of important individual sentences issued on the topic of state aid for building the infrastructure and rendering of broadband services during the period 2007-2013 and 2014-2020, as well as beyond, in the EU Member States. Thanks to that the reader gets...
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Tracking of the broadband source of the underwater noise in the very shallow water conditions
PublicationThe paper contains the result s, both theoretical and experimental , connected with the tracking of the underwater noise source as small ships, pontoon , diver and so on. The pro blem of security in the shallow water area is the challenge for underwater acousticians. In this paper there is take n into account the detection of the sources that move on the surface of the sea or underwater in shallow...
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Broadband LFM signal source for a module-based diver detection sonar
PublicationPraca przedstawia koncepcję źródła impulsów sondujących sonaru DDS, dla pogrupowanych po stronie nadawczej elementarnych sekcji przetwornika w moduły 8 lub 16 elementowe. Na podstawie oszacowania teoretycznego i pomiarów czwórnikowych określono potrzebną moc wyjściową i topologię tych nadajników. Przedstawione są też uzyskane na drodze pomiarów charakterystyki częstotliwościowe modułów przetwornika, razem z zastosowanym układem...
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Broadband Modeling of Motor Cable Impact on Common Mode Currents in VFD
PublicationExamination of conducted EMI generation and propagation in AC motor drives fed by frequency converter requires to consider parasitic capacitances in converters, motor windings and feeding cables to be taken into account. AC motor winding voltage transients and related common mode currents are significantly correlated with resonance effects occurring in converter's load circuits. Intensity levels of these phenomena depend...
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IT support for OKNO broadband Internet-based distant learning system at WUT
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Broadband NaK2Li[Li3SiO4]4:Ce Alkali Lithosilicate Blue Phosphors
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Underwater acoustic communication system using broadband signal with hyperbolically modulated frequency
PublicationThe implementation of reliable acoustic underwater communication in shallow waters is a scientific and engineering challenge, mainly due to the permanent occurrence of the multipath phenomenon. The article presents the concept of a transmission system using a broadband signal with hyperbolically modulated frequency (HFM) to transmit data symbols and synchronize data frames. The simulation tests were carried out in channels with...
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Simplified Approach for Broadband RF Testing of Low Loss Magneto-Dielectric Samples
PublicationIn this paper, an attractive measurement techniqueis proposed to retrieve the broadband permittivity and permeabil-ity of the magneto-dielectric materials. The proposed techniqueis quite novel which mitigates the major problems associatedwith the conventional broadband RF material characterizationtechniques such as numerical instability and phase uncertaintywhen the length of the sample exceeds...
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Estimation of Broadband Complex Permeability Using SIW Cavity-Based Multimodal Approach
PublicationIn this article, an attractive multimodal substrate integrated waveguide (SIW) based methodology is presented for the characterization of magnetic materials in the broadband microwave frequency. The proposed approach employs a modified feed under-coupled SIW cavity instead of conventional feed over-coupled multiple SIW cavities; it uses the modified closedform expression, developed from the first principle to consider the effect...
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Evaluating the effectiveness of Doppler frequency shift determination using pilots in broadband transmission
PublicationIn underwater communications, reciprocal motion between transmitter and receiver has a significant impact on reception quality. In orthogonal broadband systems that provide high bit rates, this problem becomes more important, especially in the higher frequency range, where the absolute Doppler shift is the greatest. Due to the low propagation speed of acoustic wave underwater, a substantial difference exists between the Doppler...
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Surrogate-Assisted Design of Checkerboard Metasurface for Broadband Radar Cross-Section Reduction
PublicationMetasurfaces have been extensively exploited in stealth applications to reduce radar cross section (RCS). They rely on the manipulation of backward scattering of electromagnetic (EM) waves into various oblique angles. However, arbitrary control of the scattering properties poses a significant challenge as a design task. Yet it is a principal requirement for making RCS reduction possible. This article introduces a surrogate-based...
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Design of a Patch Power Divider with Simple Structure and Ultra-Broadband Harmonics Suppression
PublicationThis paper introduces a simple H-shaped patch Wilkinson power divider (WPD), which provides ultra wide harmonics suppression band. The presented WPD designed at 1.8 GHz, and exhibits good performance at the operating bandwidth. In the proposed divider structure, two simple patch low-pass filters (LPFs) are employed at each branch, and three open ended stubs are added at each port. The proposed divider, implemented using the aforementioned...
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A Simple-Topology Compact Broadband Circularly Polarized Antenna With Unidirectional Radiation Pattern
PublicationIn this letter, a geometrically simple, reflector-backed single-point-fed circularly polarized (CP) antenna with unidirectional radiation pattern is presented. The structure comprises a simple coplanar waveguide (CPW) feeding circuit with an open slot etched on one side of the coplanar ground. The enhanced CP bandwidth is obtained by combining the loop mode, the slot mode, and the asymmetrical configuration of the coplanar ground...
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System identification theory-based estimation of underwater acoustic channel for broadband communications.
PublicationPłytki kanał podwodny jest niestacjonarny z powodu wielokrotnych odbić fal dźwiękowych od powierzchni wody oraz ruchu nadajnika i odbiornika systemu komunikacyjnego. Dla zapewnienia szybkiej transmisji danych niezbędna jest estymacja kanału oparta na equalizacji adaptacyjnej. W systemach komunikacji podwodnej stosowane są zazwyczaj equalizery DFE z zaimplementowanymi algorytmami najmniejszych kwadratów: LMS oraz RLS.W artykule...
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A compact spline-enhanced monopole antenna for broadband/multi-band and beyond UWB applications
PublicationIn this work, a compact monopole antenna for broadband/multi-band and beyond ultra- wideband (UWB) communication has been proposed. The structure is based on a spline-enhanced radiator with a broadband feed and a modified ground plane. Rigorous design optimization of the radiator has been performed in a two-stage framework where optimization of the structure with respect to electrical performance is followed by explicit miniaturization...
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<title>Modeling of broadband light source to use with optical coherent tomography system</title>
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Rare earth-doped barium gallo-germanate glasses for broadband near-infrared luminescence
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Chromium(III)-Doped Fluoride Phosphors with Broadband Infrared Emission for Light-Emitting Diodes
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Space-mapping-based design flow of miniaturized broadband matching transformer with perforated metallization
PublicationA 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...
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Broadband near infrared emission in antimony-germanate glass co-doped with erbium and thulium ions
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Broadband emission at NIR in double-core optical fiber co-doped with Nd3+/Yb3+ions
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Broadband Profiled Eye-Safe Emission of LMA Silica Fiber Doped with Tm3+/Ho3+ Ions
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Broadband NIR emission from rare earth doped-SiO2-Nb2O5 and SiO2-Ta2O5 nanocomposites
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A General Scheme of a Branch-and-Bound Approach for the Sensor Selection Problem in Near-Field Broadband Beamforming
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Chromium Ion Pair Luminescence: A Strategy in Broadband Near-Infrared Light-Emitting Diode Design
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