Search results for: APERTURE ANTENNAS
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Hybrid Technique Combining the FDTD Method and Its Convolution Formulation Based on the Discrete Green's Function
PublicationIn this letter, a technique combining the finite-difference time-domain (FDTD) method and its formulation based on the discrete Green's function (DGF) is presented. The hybrid method is applicable to inhomogeneous dielectric structures that are mutually coupled with wire antennas. The method employs the surface equivalence theorem in the discrete domain to separate the problem into a dielectric domain simulated using the FDTD method...
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublicationConsidering 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,...
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Parallel Implementation of the Discrete Green's Function Formulation of the FDTD Method on a Multicore Central Processing Unit
PublicationParallel implementation of the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method was developed on a multicore central processing unit. DGF-FDTD avoids computations of the electromagnetic field in free-space cells and does not require domain termination by absorbing boundary conditions. Computed DGF-FDTD solutions are compatible with the FDTD grid enabling the perfect hybridization of FDTD...
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System Loss Model for Body-to-Body Networks in Indoor and Outdoor Environments
PublicationA system loss model for body-to-body networks in indoor and outdoor environments is proposed in this paper, based on measurements taken at 2.45 GHz. The influence of the type of environment, antenna visibility and user mobility on model parameters has been investigated. A significant impact of mutual antennas’ placement and their visibility is shown. The proposed model fits well to empirical data, with the average root mean square...
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Do Leonardo da Vinci’s drawings, room acoustics and radio astronomy have anything in common?
PublicationAfter introducing Leonardo da Vinci’s (LdV) predecessors in the field of light propagation research, his drawings on the topic of reflecting light by a spherical mirror are analysed. The discovery of LdV is presented, according to which, at an infinitely distant source of rays, a small fragment of the canopy is enough to generate a focus, while the rest of the mirror forms a caustic for which LdV did not indicate an application....
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High-precision bearing estimation for active sonar with cylindrical array performed by interpolated array transformation
PublicationThe article presents a method for improving the accuracy of bearing in multibeam sonar with a cylindrical array. The antenna’s non-linear shape and the resulting non-uniform sampling of the signal in space, mean that known methods of high-resolution spectral analysis cannot be used. In order to apply an algorithm from this group, a linear virtual antenna must be produced. The paper presents a technique of mapping a cylindrical...
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Anita Mieszkowska, ETI (Tel) , II sem. 2023/2024l
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Adam Lamęcki dr hab. inż.
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Wpływ drążenia pionowego w silikatowych elementach murowych na nośność kotew wklejanych
PublicationThe article is showing results of measurements of the effectiveness of the assembly anchor of inmates glued in in sunk vertically lime-sandy blocks. Examinations were performed for cases of the assembly anchor in different fragments of blocks: in part fullwall, in an axis of symmetry and on the edge of the aperture vertical. An influence of the location of places of settling was examined anchor to the way of the forming of uniting...
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System Loss Model for Body Area Networks in Room Scenarios
PublicationThis paper presents an analysis of system loss in Body Area Networks for room scenarios, based on a wideband measurement campaign at 5.8 GHz. The measurements were performed with a fixed antenna transmitting vertically and horizontally polarised signals, while the user wears dualpolarised antennas. The average system losses in co- and crosspolarised channels are 41.4 and 42.6 dB for vertically polarised transmitted signals and...
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Non-destructive Diagnostics of the Floor in the Gdańsk Crane Using Ground Penetrating Radar = Diagnostyka nieniszcząca posadzki w gdańskim Żurawiu z zastosowaniem metody georadarowej
PublicationThis paper presents the results of a ground penetrating radar (GPR) survey carried out at the Crane in Gdańsk. The measurements were conducted on the floor of the southern and northern towers. The aim of the experiment is to assess the possibility of detecting anomalies beneath the floor. The surveys were carried out in a non-destructive manner, using a georadar unit with 2 GHz and 400/900 MHz antennas. This paper compares the...
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Włodzimierz Zieniutycz prof. dr hab. inż.
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Antenna technique in space application - 22/23
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Self-assemblies of novel magnesium porphyrins mimicking natural chlorosomal bacteriochlorophylls
PublicationSelf-assembling porphyrins are promising materials to mimic natural bacteriochlorophylls c, d, or e encountered in the chlorosomes of photosynthetic bacteria. We have studied four novel magnesium porphyrins mimicking this chlorosomal antenna system. In contrast to previous articles reporting synthetic Zn-porphyrins, our studies focus on porphyrins with Mg as the central atom, which mimic more closely the natural bacteriochlorophylls....
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Dendron to Central Core S1–S1 and S2–Sn (n>1) Energy Transfers in Artificial Special Pairs Containing Dendrimers with Limited Numbers of Conformations
PublicationTwo dendrimers consisting of a cofacial free-base bisporphyrin held by a biphenylene spacer and functionalized with 4-benzeneoxomethane (5-(4-benzene)tri-10,15,20-(4-n-octylbenzene)zinc(II)porphyrin) using either five or six of the six available meso-positions, have been synthesized and characterized as models for the antenna effect in Photosystems I and II. The presence of the short linkers, -CH2O-, and long C8H17 soluble side...
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High frequency impulse ground penetrating radar application in assessment of interlayer connections
PublicationGround Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic...
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Optical Magnetometry Based on Nanodiamonds with Nitrogen-Vacancy Color Centers
PublicationNitrogen-vacancy color centers in diamond are a very promising medium for many sensing applications such as magnetometry and thermometry. In this work, we study nanodiamonds deposited from a suspension onto glass substrates. Fluorescence and optically detected magnetic resonance spectra recorded with the dried-out nanodiamond ensembles are presented and a suitable scheme for tracking the magnetic-field value using a continuous...
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X-ray Photoelectron Spectroscopy studies of ammonium vanadate
Open Research DataThe DataSet contains the high-resolution XPS studies of the ammonium vanadate nanostructures obtained by the hydrothermal method. XPS analyses were carried out with an X-ray photoelectron spectrometer (Omicron NanoTechnology) with a 128-channel collector. The measurements were performed at room temperature in an ultra-high vacuum condition (below 1.1x10-8...
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Muhammad Usman Raza Ph.D
PeopleMuhammad Usman Raza received the B.Sc. degree from COMSATS Institute of Information Technology, Pakistan in 2014.He have done his MSc degree from University of Electronic Science and Technology of China(UESTC),Chengdu in 2018. Presently, he is pursuing his Phd degree in Information and Telecommunication Engineering at Xi'an Jiaotong University, China. He has been associated with electromagnetics and communication laboratory where...
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Michał Mrozowski prof. dr hab. inż.
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Piotr Kowalczyk dr hab. inż.
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60 GHz Microstrip Van Atta Arrays for Millimeter Wave Identification and Localization
PublicationIn this paper performance comparison of co-polarized and cross-polarized microstrip Van Atta arrays working in the 60 GHz frequency range is presented. They can be treated as simple chipless RFID tags with frequency response based identification. Tags with three different nominal resonance frequencies of 57, 62 and 67 GHz are designed by scaling optimized base model. Designed 62 GHz co-polarized and cross-polarized arrays with...
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Chemical composition of La-Sr-Ce-Ni-Ti ceramics material measured by XPS method
Open Research DataLa-Sr-Ce-Ni-Ti (LSCNT) based ceramics sample was manufactured by standard solid state reaction.Prepared powder was pressed into pilled and sintered in a furnace in air atmosphere for 10h. Annealing temperature was 1200 Celsius degree. To calculate chemical composition and determine valence states of the elements, X-Ray photoemission spectroscopy (XPS)...
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Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
PublicationElectromagnetic simulation and electronic design automation (EDA) play an important role in the design of 5G antennas and radio chips. The simulation challenges include electromagnetic effects and long simulation time and this paper focuses on simulation software based on finite-element method (FEM). The state-of-the-art EDA software using novel computational techniques based on FEM can not only accelerate numerical analysis, but...
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublicationIn this paper, an efficient computational framework for the full-wave design by optimization of complex microwave passive devices, such as antennas, filters, and multiplexers, is described. The framework consists of a computational engine, a 3D object modeler, and a graphical user interface. The computational engine, which is based on a finite element method with curvilinear higher-order tetrahedral elements, is coupled with built-in...
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Study of the chemical state of Gd in a Ba-La-Gd-Co based ceramic
Open Research DataBarium, Lanthanum, Gadolinium and Cobaltium precursors were used for production of ceramic materials. Samples were produced by standard solid state reaction. Samples were annealed at 300 Celsius degree in wet and dry atmosphere. Annealing takes 72h or 2h. Results of annealing on a Gadolinum were observed by X-Ray photoemission spectroscopy (XPS), OmicronNanotechnology....
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Mateusz Rzymowski mgr inż.
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Efekt dopplera w systemach hydrolokacyjnych
PublicationReferat zawiera przegląd problematyki zjawiska Dopplera w systemach hydrolokacyjnych. Przegląd poprzedzony jest omówieniem efektu Dopplera w kategorii kompresji czasu. Następnie przedstawiono metody wykorzystania zjawiska Dopplera do pomiaru prędkości ruchu i położeniaobserwowanych obiektów oraz wykorzystanie tego zjawiska w sonarach z syntetyczną aperturą. W drugiej części referatu omówiono negatywne skutki zjawiska Dopplera i...
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Elektroniczna Apartura Medyczna zima 23/24
e-Learning CoursesI stopień - Inżynieria biomedyczna
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Noise Analysis of Continuous GPS Time Series of Selected EPN Stations to Investigate Variations in Stability of Monument Types
PublicationThe type of monument that a GPS antenna is placed on plays a significant role in noise estimation for each permanent GPS station. In this research 18 Polish permanent GPS stations that belong to the EPN (EUREF Permanent Network) were analyzed using Maximum Likelihood Estimation (MLE). The antennae of Polish EPN stations are placed on roofs of buildings or on concrete pillars. The analyzed data covers a period of 5 years from 2008...
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Expedited Yield-Driven Design of High-Frequency Structures by Kriging Surrogates in Confined Domains
PublicationUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of high-frequency structures systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the characteristics of antennas or microwave devices. For example, in the case...
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Grzegorz Fotyga dr hab. inż.
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Influence of the annealing condictions on the chemical structure of LaBaGdCo ceramics
Open Research DataCeramic samples based on Barium, Lanthanum, Gadolinium and Cobaltium were produced by solid state reaction. After sintring in a furnance, samples were annealed at 300 Celsius degree in wet and dry atmosphere. Annealing takes 72h or 2h. Results of annealing were observed by X-Ray photoemission spectroscopy (XPS), OmicronNanotechnology. XPS analysis...
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Coastal zone monitoring using Sentinel-1 SAR polarymetry data
PublicationIn recent years the role of the surveillance and security of Polish boundaries has significantly increased. Polish coastal zone monitoring requires various approaches using various technological means in order to ensure the protection of Polish boundaries. In this paper, the authors discuss and present alternatives to underwater surveillance methods of coastal area analysis and monitoring using data retrieved from the newly developed...
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Valence state of Manganium in a MnCoO ceramics
Open Research DataManganium -cobalt based ceramics materials were produced by solid state reaction and sintred in a furnance in air atmosphere for 20h. Annealing temperature was 600 Celsius degree. For investigations a series of samples, with a various composition was chosen: MnCoO, Mn, Co2O and Mn2CoO. In order to determine valence states of the Mn, X-Ray photoemission...
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Lanthanum investigations in ceramics annealed in a dry and wet atmosphere
Open Research DataCeramics based on Barium, Lanthanum, Gadolinium and Cobaltium were produced by standard solid state reaction from oxides and carbonate powders. After sintring, samples were annealed for 2 hours or 72 hours at 300 Celsius degree in a both: wet and dry atmosphere. Results of annealing on a chemical composition and valence state of lanthanum were observed...
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Investigations of the valence state of Co in a MnCoO ceramics
Open Research DataMcCoO ceramics materials were produced by solid state reaction and sintred in a furnance in air atmosphere for 20h. Annealing temperature was 600 Celsius degree. For investigations a series of samples, with a various composition was chosen: MnCoO, Mn, Co2O and Mn2CoO. Chemical behaviour of the Cobaltium was measured by XPS method. The analyses were...
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Selected properties and parameters of radio channel impulse response estimation in ISM 2.4 GHz band
PublicationThe article presents experimental research indicating that the impulse response of the communication channel, determined in practice, are not of an universal character, but only represent its approximate value for the frequency on which this measurement was made. Phases for each of the replicas of the measurement signal were determined during the analysis of the received signals in the baseband. Phase changes of individual replicas...
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The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics
PublicationBacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding...
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Measurement and Analysis of the Radio Wave Polarisation in Off-Body Communications in Indoor Environment
PublicationThe paper describes an analysis of the radio wave polarisation in off-body communications in indoor environment. The measurement stand for polarisation measurements has been shortly described. Five investigated scenarios with different body postures and different antenna placements have been characterize. The vertical and horizontal components of received radio signal have been analysed. The measure used in analysis is a ratio...
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XPS study of the YST ceramics
Open Research DataYttrium-doped strontium titanate was prepared via conventional solid-state reaction method from Y2O3 (Sigma Aldrich, 99,9%), TiO2 (Sigma Aldrich, 99%) and SrCO3 (Sigma Aldrich,98%). For comparision, two other techniques were used for synthesis: Pechini and wet methods. Both kind of samples were measured, after and before reduction process (in a hydrogen)....
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Chemical analysis of the Au-Ag nanoaloys
Open Research DataThe nanostructures of AuAg nanoalloys were prepared by sequential sputtering of gold and silver thin films. Single layer thickness was usually 2.8 nm were deosted by magnetron sputtering method in a Ar plasma. As deposited layers were annealed in Ar atmosphere at 550 degress for 15 minutes. For XPS measurements five samples were selected: pure gold...
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Correction of determined coordinates of railway tracks in mobile satellite measurements
PublicationThis article examines one of the basic issues related to the technique of mobile satellite measurements in railway tracks. This problem concerns the correction of the determined coordinates of the track centerline. The need to perform this operation results from the GNSS receivers positioning at a certain height above the level of the existing track axis, leading to longitudinal and lateral shifts of antennas. The key problem here...
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Impact of radio wave polarisation on off-body communications in indoor environments
PublicationThis paper describes the measurements and the analysis of the impact of radio wave polarisation on off-body communications in Body Area Networks in indoor environments. Measurements on polarisation impact are briefly described. Five investigated scenarios with different body postures and different antenna placements are characterised. The difference between the vertical and horizontal components of the received radio signal are...
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Ochrona odbiorników GNSS przed zakłóceniami celowymi
PublicationArtykuł dotyczy zastosowania algorytmów przestrzennego cyfrowego przetwarzania sygnałów dla potrzeb selektywnej eliminacji sygnałów zakłócających pracę odbiorników nawigacji satelitarnej GNSS. Omówiono podatność tych odbiorników na ataki elektroniczne typu zagłuszanie oraz spoofing. Polegają one na celowej emisji sygnałów niepożądanych w paśmie pracy systemu. Następnie przedstawiono koncepcję przeciwdziałania tego rodzaju zakłóceniom...
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Diagnostyka ultradźwiękowa mostowej belki prefabrykowanej typu T metodą młoteczkową
PublicationZastosowanie prefabrykacji w budowie obiektów mostowych pozwala optymalizować zużycie energii i materiałów i tym samym redukować koszty budowanego obiektu. Prefabrykowane belki sprężone mogą występować jako elementy kablobetonowe wykonywane bezpośrednio na placu budowy lub powstawać w zakładzie prefabrykacji jako elementy strunobetonowe. Elementy prefabrykowane wytwarzane w warunkach przemysłowych muszą spełniać wymagania wysokiej trwałości,...
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Interferencja szerokopasmowa w wieloźródłowych systemach akustycznych
PublicationW akustycznych systemach wieloźródłowych pobudzanych wspólnym szerokopasmowym sygnałem dźwiękowym występuje zjawisko interferencji powodujące znaczne zniekształcenia liniowe. W artykule do badania tego zjawiska zastosowano metodę odpowiedzi impulsowych, traktując system wieloźródłowy, jako wielokanałowy liniowy system komunikacyjny. Przestudiowano mechanizm formowania się pola akustycznego dla szczególnego przypadku liniowego szyku...
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A Cross-Polarisation Discrimination Analysis of Off-Body Channels in Passenger Ferryboat Environments
PublicationThere is a need for investigating radio channels for Body Area Networks considering the depolarisation phenomenon and new types of environments, since these aspects are becoming very important for systems design and deployment. This paper presents an analysis of cross-polarisation discrimination for off-body channels based on a measurement campaign performed in a passenger ferryboat, i.e., where all walls, floors and ceilings are...
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System wykrywania i przeciwdziałania spoofingowi GPS
PublicationSpoofing w systemach nawigacji satelitarnej jest atakiem elektronicznym, który polega na nieuprawnionej emisji sygnałów stanowiących imitacje rzeczywistych sygnałów odbieranych z satelitów. Powoduje on wyznaczenie nieprawidłowych informacji o czasie, położeniu i prędkości odbiornika. Z uwagi na trudność jego wykrycia, spoofing stanowi poważniejsze zagrożenie niż proste zagłuszanie sygnałów zakłóceniem o dużej mocy (ang. jamming)....
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Dual-Polarized Wideband Bandpass Metasurface-Based Filter
PublicationThis paper presents a novel metasurface-based bandpass filter. The structure is realized by simply patterning a double-sided AD250 substrate, and does not require any vias or insertion of lumped elements. The top layer is an annular- aperture-array with multiple inner conductors, whereas the bottom layer is a first-order Hilbert-curve array. FEM-based simulation results of the filter are obtained using HFSS. The experimental validation...