Wyszukiwarka
Filtry
wszystkich: 1706
wybranych: 1422
-
Katalog
- Publikacje 1422 wyników po odfiltrowaniu
- Czasopisma 8 wyników po odfiltrowaniu
- Wydawnictwa 1 wyników po odfiltrowaniu
- Osoby 74 wyników po odfiltrowaniu
- Wynalazki 7 wyników po odfiltrowaniu
- Projekty 13 wyników po odfiltrowaniu
- Laboratoria 3 wyników po odfiltrowaniu
- Zespoły Badawcze 5 wyników po odfiltrowaniu
- Aparatura Badawcza 4 wyników po odfiltrowaniu
- Kursy Online 55 wyników po odfiltrowaniu
- Wydarzenia 7 wyników po odfiltrowaniu
- Dane Badawcze 107 wyników po odfiltrowaniu
Filtry wybranego katalogu
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: anteny wieloelementowe
-
Stanowisko do Pomiaru Charakterystyk Promieniowania Anten w Paśmie 2-18 GHz
PublikacjaPraca przedstawia budowę oraz wyposażenie stanowiska do pomiaru charakterystyk promieniowania anten, będącego częścią laboratorium antenowego Katedry Inżynierii Mikrofalowej i Antenowej. Opisywane stanowisko umożliwia aktualnie wykonywanie pomiarów anten mikrofalowych w paśmie 2-18 GHz. W pracy przybliżono zasadę działania układu pomiarowego oraz konfigurację sprzętową służącą do pomiaru w konkretnych podpasmach. Przedstawiono...
-
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.
-
Depression and anxiety in coronary artery bypass grafting patients
Publikacja -
Inexpensive Helical Antenna for Global Navigation Satellite Systems
PublikacjaZaprezentowane 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...
-
Compact CPW-fed Sierpinski fractal monopole antenna.
PublikacjaZaproponowano 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.
-
Broadband Microstrip Patch Antenna with Reduced Transversal Size
PublikacjaW 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...
-
Compact antenna array comprising fractal-shaped microstripradiators
PublikacjaA design method of antenna array consisting of eight microstrip patches modified with Sierpinski fractal curves has been presented andexperimentally validated in this paper. Method proposed has enabled the achievement of considerable miniaturization of array length (26%),together with multi-band behavior of the antenna, which proves the attractiveness of presented design methodology and its ability to be implemented in more complex...
-
A structure and design of a novel compact UWB MIMO antenna
PublikacjaIn the paper, a concept and design procedure of a novel compact MIMO slot antenna is presented. In order to achieve a better filling of available space, individual antennas are constrained to a triangular shape and optimized for a reduced size. The MIMO structure is then assembled using the two of previously designed antennas in orthogonal arrangement. Surrogate-assisted numerical optimization involving variable-fidelity electromagnetic...
-
Novel structure and design of compact UWB slot antenna
PublikacjaIn this paper, a novel structure of a compact UWB slot antenna is presented along with a simulation-driven design optimization algorithm for adjusting geometry parameters of the device. Our primary objective is to obtain small footprint of the structure while maintaining its acceptable electrical performance. It is achieved by introducing sufficiently large number of geometry degrees of freedom, including increased number of parameterized...
-
Diagnostics of thermal processes in antenna systems of broadcast stations
PublikacjaDiagnostics is an important element associated with the operation of a radio antenna systems, allowing earlier detection of potential damage. Thermography is one of the diagnostic tools, which allows for non-invasive assessment of technical condition. It brings together both financial savings associated with the removal of the damage and the potential effects caused by it. The article presents an example of using a thermal imaging...
-
Small Antenna Design Using Surrogate-Based Optimization
PublikacjaIn this work, design of small antennas using efficient numerical optimization is investigated. We exploit variable-fidelity electromagnetic (EM) simulations and the adaptively adjusted design specifications (AADS) technique. Combination of these methods allows us to simultaneously adjust multiple geometry parameters of the antenna structure of interest in a computationally feasible manner, leading to substantial reduction of the...
-
Single-Anchor Indoor Localization Using ESPAR Antenna
PublikacjaIn this paper a new single-anchor indoor localization concept employing Electronically Steerable Parasitic Array Radiator (ESPAR) antenna has been proposed. The new concept uses a simple fingerprinting algorithm adopted to work with directional main beam and narrow minimum radiation patterns of ESPAR antenna that scans 360° area around the base station, while the signal strength received from a mobile terminal is being recorded...
-
A Geometrically Simple Compact Wideband Circularly Polarized Antenna
PublikacjaA compact broadband wide-slot circular polarization (CP) antenna is proposed. An inverted L-shape parasitic strip at the open end of a microstrip line extension and a slot modification is applied to attain wideband CP. The advantage of this technique is simplicity which makes it readily re-designable for different frequency bands. To demonstrate the concept, three designs working at different frequencies are obtained. The redesign...
-
Design optimization of novel compact circular polarization antenna
PublikacjaThe paper describes a structure and a design optimization procedure of a miniaturized circular polarization antenna with elliptical ground plane slots and feed line with stepped-impedance stubs. Constrained optimization of all antenna parameters is executed in order to explicitly reduce the antenna size while maintaining required impedance axial ratio bandwidth of 5 GHz to 7 GHz at the same time. The size of the optimized antenna...
-
Knowledge-based performance-driven modeling of antenna structures
PublikacjaThe importance of surrogate modeling techniques in the design of modern antenna systems has been continuously growing over the recent years. This phenomenon is a matter of practical necessity rather than simply a fashion. On the one hand, antenna design procedures rely on full-wave electromagnetic (EM) simulation tools. On the other hand, the computational costs incurred by repetitive EM analyses involved in solving common tasks...
-
The functions of securities law: An expert survey of legislative intent in Poland
Publikacja -
Simple Superstrate Antenna for Connectivity Improvement in Precision Farming Applications
PublikacjaIn this paper, a concept of a simple circularly polarized antenna with partially reflecting surface (PRS) has been adopted for precision farming applications. The investigation contains an analysis of the dependence of the antenna performance on the elements number in the PRS structure in X- and Ka-band frequencies. Especially meaningful parameters from point-to-point connectivity perspective are...
-
Hypertension and coronary artery disease: Mechanistic insights and therapeutic challenges
Publikacja -
Some Aspects in the Model of a Wire Antenna by Using the Mathcad Language
PublikacjaW artykule omówiono możliwość modelowania anteny prętowej przy wykorzystaniu programu Mathcad. Przedstawiono sposób rozwiązywania równania różniczkowo-całkowego na przykładzie równania Pocklingtona. Artykuł zawiera szczegółowy opis modelu, uzyskane wyniki obliczeniowe i wnioski na temat użyteczności metody i problemów związanych ze zbieżnością zastosowanych algorytmów numerycznych.
-
Review of Recent Advancement on Nature/Bio-inspired Antenna Designs
PublikacjaThis article presents an extensive examination of antennas rooted in nature and biology, showcasing their remarkable performance across a wide spectrum of frequencies—from microwave to terahertz. The limitations of traditional antenna design have become increasingly evident in the face of burgeoning demands for novel communication technologies. Conventional analytical-equation-based approaches struggle to deliver the combined performance...
-
Adaptive Wavelet-Based Correction of Non-Anechoic Antenna Measurements
PublikacjaNon-anechoic measurements represent an affordable alternative to evaluation of antenna performance in expensive, dedicated facilities. Due to interferences and noise from external sources of EM radiation, far-field results obtained in non-ideal conditions require additional post-processing. Conventional correction algorithms rely on manual tuning of parameters, which make them unsuitable for reliable testing of prototypes. In this...
-
Szyk antenowy z wykorzystaniem radiatorów o brzegu fraktalnym
PublikacjaW pracy zaprezentowano metodykę projektowania ośmioelementowego szyku antenowego w technologii niesymetrycznej linii paskowej z wykorzystaniem promienników o brzegu zmodyfikowanym krzywą fraktalną będącą krzyżem Sierpińskiego. Zastosowanie nowego kształtu łat pozwoliło na uzyskanie 26% miniaturyzacji szyku antenowego przy jednoczesnym poszerzeniu pasma pracy wraz ze zmniejszeniem odległości pomiędzy łatam. Wykazano także znikomy...
-
Szerokopasmowy szyk antenowy wykorzystujący radiatory o brzegu fraktalnym
PublikacjaW pracy przedstawiono koncepcje szyku antenowego zbudowanego w technologii mikropaskowej, w oparciu o promienniki szczelinowe ze zmodyfikowanym kształtem brzegu. Modyfikacje brzegów szczeliny przeprowadzono wykorzystując krzywe fraktalne. Omówiono metodykę projektowania czteroelementowego szyku antenowego, którego radiatory posiadają krawędzie o kształcie fragmentu krzywej von Kocha (druga iteracja). Zaproponowano obwód zasilający...
-
Computationally Efficient Design Optimization of Compact Microwave and Antenna Structures
PublikacjaMiniaturization is one of the important concerns of contemporary wireless communication systems, especially regarding their passive microwave components, such as filters, couplers, power dividers, etc., as well as antennas. It is also very challenging, because adequate performance evaluation of such components requires full-wave electromagnetic (EM) simulation, which is computationally expensive. Although high-fidelity EM analysis...
-
A Concept and Design Optimization of Compact Planar UWB Monopole Antenna
PublikacjaA novel structure concept of a compact UWB monopole antenna is introduced together with a low-cost design optimization procedure. Reduced footprint is achieved by introduction of a protruded ground plane for current path increase and a matching transformer to ensure wideband impedance matching. All geometrical parameters of the structure are optimized simultaneously by means of surrogate based optimization involving variable-fidelity...
-
Multi-objective antenna design by means of sequential domain patching
PublikacjaA simple yet robust methodology for rapid multiobjective design optimization of antenna structures has been presented. The key component of our approach is sequential domain patching of the design space which is a stencil-based search that aims at creating a path that connects the extreme Pareto-optimal designs, obtained by means of single-objective optimization runs. The patching process yields the initial approximation of the...
-
Pial artery and subarachnoid width response to apnoea in normal humans
PublikacjaBackground: Little is known about intracranial pressure (ICP)-cerebral haemodynamic interplay during repetitive apnoea. A recently developed method based on near-infrared transillumination/backscattering sounding (NIR-T/BSS) noninvasively measures changes in pial artery pulsation (cc-TQ) as well as subarachnoid width (sas-TQ) in humans. Method: We tested the complex response of the pial artery and subarachnoid width to apnoea...
-
Detection and Mitigation of GPS Spoofing Based on Antenna Array Processing
PublikacjaIn this article authors present an application of spatial processing methods for GPS spoofing detection and mitigation. In the first part of this article, a spoofing detection method, based on phase delay measurements, is proposed. Accuracy and precision of phase delay estimation is assessed for various qualities of received signal. Spoofing detection thresholds are determined. Efficiency of this method is evaluated in terms of...
-
Antenna Optimization Using Machine Learning with Reduced-Dimensionality Surrogates
PublikacjaIn modern times, antenna design has become more demanding than ever. The escalating requirements for performance and functionality drive the development of intricately structured antennas, where parameters must be meticulously adjusted to achieve peak performance. Often, global adjustments to geometry are necessary for optimal results. However, direct manipulation of antenna responses evaluated with full-wave electromagnetic (EM)...
-
Dimensionality-Reduced Antenna Modeling with Stochastically Established Constrained Domain
PublikacjaOver the recent years, surrogate modeling methods have become increasingly widespread in the design of contemporary antenna systems. On the one hand, it is associated with a growing awareness of numerical optimization, instrumental in achieving high-performance structures. On the other hand, considerable computational expenses incurred by massive full-wave electromagnetic (EM) analyses, routinely employed as a major design tool,...
-
Specification-Oriented Automatic Design of Topologically Agnostic Antenna Structure
PublikacjaDesign of antennas for modern applications is a challenging task that combines cognition-driven development of topology intertwined with tuning of its parameters using rigorous numerical optimization. However, the process can be streamlined by neglecting the engineering insight in favor of automatic de-termination of structure geometry. In this work, a specification-oriented design of topologically agnostic antenna is considered....
-
Millimeter Wave Negative Refractive Index Metamaterial Antenna Array
PublikacjaIn this paper, a novel negative refractive index metamaterial (NIM) is developed and characterized. The proposed metamaterial exhibits negative effective permittivity (εeffe) and negative effective permeability (µeffe) at millimeter wave frequency of 28GHz. This attractive feature is utilized to enhance the gain of a microstrip patch antenna (MPA). Two thin layers of 5 5 subwavelength unit cell array of NIM are placed above a...
-
AngioScore: An artificial intelligence tool to assess coronary artery lesions
PublikacjaThe functionality scope of the AngioScore tool in semi-automatic assessment of stenoses according to the SYNTAX scale was presented. An evaluation of the preliminary accuracy of AngioScore in lesion assessment was performed.
-
Influence of realistic antenna radiation pattern on rf fingerprinting accuracy
Publikacja -
A Broadband Circularly Polarized Wide-Slot Antenna with a Miniaturized Footprint
PublikacjaThis 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...
-
Performance-Based Nested Surrogate Modeling of Antenna Input Characteristics
PublikacjaUtilization of electromagnetic (EM) simulation tools is mandatory in the design of contemporary antenna structures. At the same time, conducting designs procedures that require multiple evaluations of the antenna at hand, such as parametric optimization or yield-driven design, is hindered by a high cost of accurate EM analysis. To certain extent, this issue can be addressed by utilization of fast replacement models (also referred...
-
Simulation-driven design of compact ultra-wideband antenna structures
PublikacjaPurpose–The purpose of this paper is to investigate strategies and algorithms for expedited designoptimization and explicit size reduction of compact ultra-wideband (UWB) antennas.Design/methodology/approach–Formulation of the compact antenna design problem aiming atexplicit size reduction while maintaining acceptable electrical performance is presented. Algorithmicframeworks are described suitable for handling various design situations...
-
Influence of Dielectric Overlay Dimensions on Performance of Miniaturized ESPAR Antenna
PublikacjaIn this paper, the influence of dielectric overlay size on miniaturized ESPAR antenna performance has been investigated. The dielectric overlay’s main function is antenna’s size reduction but it can also be used to modify its radiation pattern. This creates the possibility of easy adopting antenna parameters to different applications by swapping used overlay. In particular, the lowering of antenna’s main beam elevation direction...
-
Dual-band antenna with improved gain for WLAN and ISM applications
PublikacjaIn this Letter, a dual-band antenna with an improved gain is proposed. The structure features 9.7 and 10.4 dBi gain within 2.4 GHz to 2.5 GHz and 5 GHz to 6 GHz bands, respectively. This makes it suitable for WLAN and ISM applications. The structure comprises an asymmetrical pair of radiators and slots suspended over a reflector. The antenna is optimised in a two-stage process using a trust-region-based gradient search algorithm....
-
Compact Dual-Polarized Corrugated Horn Antenna for Satellite Communications
PublikacjaIn this paper, a structure and design procedure of a novel compact dual-polarized corrugated horn antenna with high gain and a stable phase center for satellite communication is presented. The antenna incorporates an Ortho-Mode Transducer (OMT), a mode converter, and a corrugated structure. The compact OMT section is designed to be fed by standard WR-75 waveguides. The proposed compact design utilizes only ten corrugated slots...
-
Asymmetrical-Slot Antenna with Enhanced Gain for Dual-Band Applications
PublikacjaDual-band operation is an important feature of antennas to be applied in modern communication systems. Although high gain of radiators is rarely of concern in urban areas with densely located broadcasting stations, it becomes crucial for systems operating in more remote environments. In this work, a dual-band antenna with enhanced bandwidth is proposed. The structure consists of a driven element in the form of an asymmetrical radiator/slot...
-
Expedited optimization of antenna input characteristics with adaptive Broyden updates
PublikacjaSimulation-driven adjustment of geometry and/or material parameters is a necessary step in the design of contemporary antenna structures. Due to their topological complexity, other means, such as supervised parameter sweeping, does not usually lead to satisfactory results. On the other hand, rigorous numerical optimization is computationally expensive due to a high cost of underlying full-wave electromagnetic (EM) analyses, otherwise...
-
Frequency-Based Regularization for Improved Reliability Optimization of Antenna Structures
PublikacjaThe paper proposes a modified formulation of antenna parameter tuning problem. The main ingredient of the presented approach is a frequency-based regularization. It allows for smoothening the functional landscape of the assumed cost function, defined to encode the prescribed design specifications. The regularization is implemented as a special penalty term complementing the primary objective and enforcing the alignment of the antenna...
-
Expedited antenna optimization with numerical derivatives and gradient change tracking
PublikacjaDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
-
ESPAR Antenna-Based WSN Node With DoA Estimation Capability
PublikacjaIn this paper, we present a low-cost energy-efficient electronically steerable parasitic array radiator (ESPAR) antenna-based wireless sensor network (WSN) node designed for IEEE 802.15.4 standard that is capable of performing direction of arrival (DoA) estimation in real-life outdoor environments. To this end, we propose the WSN node architecture, design and realization that utilizes NXP JN5168 radio frequency (RF) wireless transceiver...
-
On geometry parameterization for simulation-driven design closure of antenna structures
PublikacjaFull-wave electromagnetic (EM) simulation tools have become ubiquitous in antenna design, especially final tuning of geometry parameters. From the reliability standpoint, the recommended realization of EM-driven design is through rigorous numerical optimization. It is a challenging endeavor with the major issues related to the high computational cost of the process, but also the necessity of handling several objectives and constraints...
-
Tolerance Optimization of Antenna Structures by Means of Response Feature Surrogates
PublikacjaFabrication tolerances and other types of uncertainties, e.g., the lack of precise knowledge of material parameters, have detrimental effects on electrical and field performance of antenna systems. In the case of input characteristics these are particularly noticeable for narrow- and multi-band antennas where deviations of geometry parameters from their nominal values lead to frequency shifts of the operating frequency bands. Improving...
-
Estymacja współrzędnych kątowych w radarze trójwspółrzędnym z elektronicznym skanowaniem wiązki i obracaną anteną planarną
PublikacjaW rozprawie zawarto historię radiolokacji oraz sposób obróbki sygnałów i danych radarowych przed etapem estymacji. Przedstawiono oraz przetestowano klasyczne metody estymacji współrzędnych wraz ze wskazaniem ich słabych oraz mocnych stron. Zaproponowano uodpornione warianty estymatorów największej wiarygodności, które pozwolił poprawić jakość oszacowania przy estymacji elewacji w warunkach propagacji wielodrogowej, redukując jednocześnie...
-
Badanie i analiza anten PCB w zastosowaniu ich w urządzeniach o ograniczonych rozmiarach
PublikacjaNiniejsze opracowanie zawiera wyniki przeprowadzonych badań dotyczących drukowanych anten o niewielkich rozmiarach. Celem tych badań było wytypowanie anten pracujących w pasmie 868MHz, które mogłyby znaleźć zastosowanie w urządzeniach do monitorowania położenia osób w środowiskach zamkniętych.
-
Caveolin 2: a facultative marker of unfavourable prognosis in long-term patency rate of internal thoracic artery grafts used in coronary artery bypass grafting. Preliminary report
Publikacja