Search results for: BAND-NOTCH ANTENNAS
-
Dirac fermions and possible weak antilocalization in LaCuSb2
PublicationLayered heavy-metal square-lattice compounds have recently emerged as potential Dirac fermion materials due to bonding within those sublattices. We report quantum transport and spectroscopic data on the layered Sb square-lattice material LaCuSb2. Linearly dispersing band crossings, necessary to generate Dirac fermions, are experimentally observed in the electronic band structure observed using angle-resolved photoemission spectroscopy,...
-
Finite Element Approaches to Model Electromechanical, Periodic Beams
PublicationPeriodic structures have some interesting properties, of which the most evident is the presence of band gaps in their frequency spectra. Nowadays, modern technology allows to design dedicated structures of specific features. From the literature arises that it is possible to construct active periodic structures of desired dynamic properties. It can be considered that this may extend the scope of application of such structures. Therefore,...
-
Shape Memory Alloy-Based Fluidically Reconfigurable Metasurfaced Beam Steering Antenna
PublicationA low-cost actuator-based fluidically programmable metasurface (FPMS) antenna is proposed to solve the slow tuning speed problem of the manually fluidic based reconfigurable antennas. The FPMS-based antenna is probe-fed and comprises a 4 × 4 square ring metasurface as a superstrate. Moreover, two shape memory alloy (SMA)-based electrically-controlled actuators are employed in the design for controlling the position of the 3D-printed...
-
Mutual Coupling Reduction in Antenna Arrays Using Artificial Intelligence Approach and Inverse Neural Network Surrogates
PublicationThis paper presents a novel approach to reduce undesirable coupling in antenna arrays using custom-designed resonators and inverse surrogate modeling. To illustrate the concept, two stand-ard patch antenna cells with 0.07λ edge-to-edge distance are designed and fabricated to operate at 2.45 GHz. A stepped-impedance resonator is applied between the antennas to suppress their mutual coupling. For the first time, the optimum values...
-
Optical properties of tellurium dioxide thin films
Open Research DataTeO2 and TeO2 doped by Eu thin films manufactured by magnetron sputtering method were measured by optical spectroscopy. Metallic Te target and Te-Eu mosaic target with diameter of 50.8 mm were sputtered for about 45 min in argon-oxygen atmosphere what resulted in 300 nm film thickness deposition. The pressure in the chamber was below 0.2 Pa and substrate...
-
Enhanced switched parasitic antenna with switched active monopoles for indoor positioning systems
PublicationThis paper presents the concept of enhanced reduced-size steerable antenna array with two rows of switched active and passive elements. Designed array is similar to ESPAR antenna but it has a set of switched monopoles instead of central one. It is intended for 2.4 GHz ISM applications with emphasis on indoor positioning systems (IPS). Proposed antenna provides improved radiation parameters and reduced dimensions in comparison to...
-
Time domain model of the resonance-based electromagnetic pulses emission system
PublicationIn the literature, the emission properties of the electromagnetic field pulse systems based on high voltage antennas (HVR) have been widely described. In order to increase the emission efficiency by extending duration and increasing amplitude of the impulse it is possible to use a resonance system tuned to the parameters of the signal shaped in the pulse forming circuit. The synthesis of a time-domain simulation model of a complex...
-
Redox State Sensitive Spectroscopy of the Model Compound [(H-dcbpy)(2)Ru-II(NCS)(2)](2-) (dcbpy=2,2 '-Bipyridine-4,4 '-dicarboxylato)
PublicationThe charge transfer reaction mechanism in a ruthenium polypyridine model complex with isothiocyanato ligands, i.e., [(H-dcbpy)(2)Ru(NCS)(2)](2-) 2Bu(4)N(+) (Ru2H) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylato), has been investigated by combining UV-vis absorption, resonance Raman spectroscopy, and electrochemical methods. Understanding the photophysics of light-harvesting complexes of this class is an indispensable prerequisite to...
-
Highly Occupied Surface States at Deuterium-Grown Boron-Doped Diamond Interfaces for Efficient Photoelectrochemistry
PublicationPolycrystalline boron-doped diamond is a promising material for high-power aqueous electrochemical applications in bioanalytics, catalysis, and energy storage. The chemical vapor deposition (CVD) process of diamond forma-tion and doping is totally diversified by using high kinetic energies of deu-terium substituting habitually applied hydrogen. The high concentration of deuterium in plasma induces atomic arrangements and steric...
-
The magnetic field measurements in selected places of the industrial building
Open Research DataThe dataset is part of a comprehensive study on the assessment of the electromagnetic field intensity in a building of an operating industrial plant. Detailed results of magnetic field measurements, carried out in selected places of this building, are presented.
-
Case Study of Old Steel Riveted Railway Truss Bridge: From Material Characterization to Structural Analysis
PublicationThe structural analysis of an old steel riveted railway truss bridge located over the Maruska River on the Działdowo – Olsztyn, Poland railway line is performed in this paper to check its behaviour under today’s railway loads. The mechanical properties of construction steel extracted from the old steel bridge are investigated by tensile tests, impact tests through the Charpy pendulum impact V-notch, and an optical emission spectrometer....
-
FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublicationThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
-
SENSITIVITY ANALYSIS IN THE REHABILITATION OF HISTORIC TIMBER STRUCTURES ON THE EXAMPLES OF GREEK CATHOLIC CHURCHES IN POLISH SUBCARPATHIA
PublicationThis work concerns structural and sensitivity analysis of carpentry joints used in historic wooden buildings in south-eastern Poland and western Ukraine. These are primarily sacred buildings and the types of joints characteristic for this region are saddle notch and dovetail joints. Thus, in the study the authors focus on these types of corner log joints. Numerical models of the joints are defined and finite element simulations...
-
Improved-Efficacy EM-Based Antenna Miniaturization by Multi-Fidelity Simulations and Objective Function Adaptation
PublicationThe growing demands for integration of surface mount design (SMD) antennas into miniatur-ized electronic devices have been continuously imposing limitations on the structure dimen-sions. Examples include embedded antennas in applications such as on-board devices, picosatel-lites, 5G communications, or implantable and wearable devices. The demands for size reduction while ensuring a satisfactory level of the electrical and field...
-
Loudness Scaling Test Based on Categorical Perception
PublicationThe main goal of this research study is focused on creating a method for loudness scaling based on categorical perception. Its main features, such as: way of testing, calibration procedure for securing reliable results, employing natural test stimuli, etc., are described in the paper and assessed against a procedure that uses 1/2-octave bands of noise (LGOB) for the loudness growth estimation. The Mann-Whitney U-test is employed...
-
Reduced-Cost Two-Level Surrogate Antenna Modeling using Domain Confinement and Response Features
PublicationElectromagnetic (EM) simulation tools have become indispensable in the design of contemporary antennas. Still, the major setback of EM-driven design is the associated computational overhead. This is because a single full-wave simulation may take from dozens of seconds up to several hours, thus, the cost of solving design tasks that involve multiple EM analyses may turn unmanageable. This is where faster system representations (surrogates)...
-
Variable-Fidelity Simulation Models and Sparse Gradient Updates for Cost-Efficient Optimization of Compact Antenna Input Characteristics
PublicationDesign of antennas for the Internet of Things (IoT) applications requires taking into account several performance figures, both electrical (e.g., impedance matching) and field (gain, radiation pattern), but also physical constraints, primarily concerning size limitation. Fulfillment of stringent specifications necessitates the development of topologically complex structures described by a large number of geometry parameters that...
-
Photocatalytic hydrogen evolution from glycerol-water mixture under visible light over zinc indium sulfide (ZnIn2S4) nanosheets grown on bismuth oxychloride (BiOCl) microplates
PublicationZnIn2S4 (ZIS) is one of the widely studied photocatalyst for photocatalytic hydrogen evolution applications due to its prominent visible light response and strong reduction ability. However, its photocatalytic glycerol reforming performance for hydrogen evolution has never been reported. Herein, the visible light driven BiOCl@ZnIn2S4 (BiOCl@ZIS) composite was synthesized by growth of ZIS nanosheets on a template-like hydrothermally...
-
A Compact Basis for Reliable Fast Frequency Sweep via the Reduced-Basis Method
PublicationA reliable reduced-order model (ROM) for fast frequency sweep in time-harmonic Maxwell’s equations by means of the reduced-basis method is detailed. Taking frequency as a parameter, the electromagnetic field in microwave circuits does not arbitrarily vary as frequency changes, but evolves on a very low-dimensional manifold. Approximating this low-dimensional manifold by a low dimension subspace, namely, reduced-basis space, gives...
-
NON-LOCAL VOLUMETRIC APPROACH TO ANALYSIS DEFECT'S SHAPE INFLUENCE ON SPECIMENS DURABILITY SUBJECTED TO BENDING AND TORSION
PublicationThe influence of defect features on fatigue behaviour is a complex trivial issue. Although the important advances over the last decades, the dialectical relationship between the defect orientation and durability is not clearly understood. The paper aims at studying the influence of the orientation of elliptical defects on the durability of samples made of C45 steel. Three types of samples with elliptical defects were subjected...
-
Analysis of magnetic field inside thin-layer ferromagnetic objects
PublicationResults of the numerical analysis of the magnetic field inside an infinitely long, thin-layer ferromagnetic pipe with and without a barrier were presented in this paper. Two wires with current symmetrically placed on two sides of the pipe are the sources of magnetic field. Numerical calculations for the quasi-steady state for chosen frequency band were carried out in the Flux 2D.
-
A novel luminescent chemical sensor for the determination of Pb 2+ and Cu 2+ ions
PublicationSilica xerogel surface grafted with aminopropyl (PrNH2) groups was additionally treated by cetyltrimethylammonium bromide (CTAB) surfactant and ascorbic acid (asc) in alkaline solution. This material symbolized as SiO2-PrNH2-CTAB/asc, proved to be a stable luminescent material, exhibited an emission band peaked at 393 nm under excitation wavelength 335 nm. Time evolution of the band intensity suggests changes of defect concentration...
-
Frequency-Reconfigurable Hybrid SIW-Based Self-Diplexing Antenna Using Solid and Liquid Dielectric Loading
PublicationThis paper presents a novel frequencyreconfigurable self-diplexing antenna (SDA) utilizing a hybrid substrate-integrated waveguide (SIW). The antenna comprises a radiating slot, a feeding network, and a hybrid SIW cavity featuring half-mode circular and half-mode rectangular SIW structures. The unique feature of this antenna lies in its fine-tuning capability of each resonant frequency by inserting or injecting solid and liquid...
-
Broadband Compact Single-Layer Magic-T Junction with Separation of DC Signals between All Ports
PublicationA novel structure for a four-port microstrip magic-T junction is presented. The device is composed of microstrip and slotline circuits etched onto two sides of a dielectric substrate. The device is extremely compact and occupies an area more than three times smaller than similar structures recently reported in the literature. The novelty of the device lies in the use of microstrip/slotline transitions for both input ports: summation...
-
A facile method for Tauc exponent and corresponding electronic transitions determination in semiconductors directly from UV–Vis spectroscopy data
PublicationIn this work, a facile method allowing for estimation of the exponent in the Tauc equation directly from the UV–vis spectra is presented. It is based on the Taylor expansion of the logarithmic version of the Tauc equation. The Tauc exponent is calculated from the tangent slope of the absorption data. Knowledge of this coefficient provides information about the optical transition types and is used as an input for the calculations...
-
On Inadequacy of Sequential Design of Experiments for Performance-Driven Surrogate Modeling of Antenna Input Characteristics
PublicationDesign of contemporary antennas necessarily involves electromagnetic (EM) simulation tools. Their employment is imperative to ensure evaluation reliability but also to carry out the design process itself, especially, the adjustment of antenna dimensions. For the latter, traditionally used parameter sweeping is more and more often replaced by rigorous numerical optimization, which entails considerable computational expenses, sometimes...
-
Comparison of different one-parameter damage laws and local stress-strain approaches in multiaxial fatigue life assessment of notched components
PublicationThis paper aims to compare the predictive capabilities of different one-parameter damage laws and local stress-strain approaches to assess the fatigue lifetime in notched components subjected to proportional bending-torsion loading. The tested fatigue damage parameters are defined using well-known stress-based, strain-based, SWT-based and energy-based relationships. Multiaxial cyclic plasticity at the notch-controlled process zone...
-
Detection of the Direct Sequence Spread Spectrum Signals with BPSK Modulation
PublicationThis paper presents a method of the DS CDMA signals with BPSK modulation detection through the examination of the enhanced signal spectrum density. On the base of experiments carried out on the real radio communication signals the impact of a narrowband emission occurring in the examined frequency band on the detection process effectiveness was shown. The results of the experiment aimed at the detection of the satellite navigation...
-
RECENT ADVANCES IN GRAPHENE APPLICATION FOR ELECTRONIC SENSING
PublicationThe great interest in graphene is caused by its potential for constructing various sensors exhibiting excellent parameters. The high carrier mobility and the unique band structure of graphene makes it promising especially in the field-effect transistors (GFET) applications. In this article, recent advances of the selected graphene-based sensor applications were presented and the possible directions for further investigations were...
-
Influence of accelerometer signal pre-processing and classification method on human activity recognition
PublicationA study of data pre-processing influence on accelerometer-based human activity recognition algorithms is presented. The frequency band used to filter-out the accelerometer signals and the number of accelerometers involved were considered in terms of their influence on the recognition accuracy. In the test four methods of classification were used: support vector machine, decision trees, neural network, k-nearest neighbor.
-
Design of OFDM-based radio communication systems for coast-to-sea and coast-to-air propagation environments
PublicationIn the paper the study of radio communication system design process for systems based on OFDM transmission is considered. The signal propagation model for 1.4 GHz frequency band is discussed, and the study of signal propagation characteristics, important from the point of view of OFDM system design, is presented. The methodology of OFDM interface design is proposed and some characteristics of the OFDM-based radio communication...
-
Highly Visible-Light-Photoactive Heterojunction Based on TiO2 Nanotubes Decorated by Pt Nanoparticles and Bi2S3 Quantum Dots
PublicationA heterojunction with excellent visible light response and stability based on titanium dioxide nanotubes (TiO2 NTs), bismuth sulfide quantum dots (Bi2S3 QDs), and platinum nanoparticles (Pt NPs) is proposed. Both Pt NPs (3.0 ± 0.2 nm) and Bi2S3 QDs (3.50 ± 0.20 nm) are well distributed on the (i) top parts, (ii) inner walls, and (iii) outer walls of the TiO2 NTs. Visible-light-induced photoreaction was initialized by excitation...
-
High frequency dynamics of an isotropic Timoshenko periodic beam by the use of the Time-domain Spectral Finite Element Method
PublicationIn this work results of numerical simulations and experimental measurements related to the high frequency dynamics of an aluminium Timoshenko periodic beam are presented. It was assumed by the authors that the source of beam structural periodicity comes from periodical alterations to its geometry due to the presence of appropriately arranged drill-holes. As a consequence of these alterations dynamic characteristics of the beam...
-
RF Multi-Functional Input-Reflectionless Dispersive-Delay Structure With Sharp-Rejection Filtering Using Channelization Techniques
PublicationA class of RF multi-functional input-reflectionless dispersive-delay structure (DDS) with linear-type in-band groupdelay variation and sharp-rejection bandpass-filtering capability is reported. It exploits a two-branch-channelized/balanced-type circuit with similar low-order reflective DDS units inside its channels, which are connected through input/output 3-dB quadrature wideband couplers. The adopted DDS unit is based on a coupledresonator...
-
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...
-
Compact antenna array comprising fractal-shaped microstripradiators
PublicationA 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...
-
Interference aware bluetooth scatternet (re)configuration algorithm IBLUERA
PublicationThis paper presents a new algorithm IBLUEREA, which enables reconfiguration of Bluetooth scatternet to reduce interference. IBLUEREA makes use of the complex model comparing ISM environment efficiency. The mechanism envisages the use of the assessment of the probability of successful (unsuccessful) frame transmission in order to take a decision concerning co-existence of technologies which make use of the same ISM band (here Bluetooth...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 75 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 65 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 90 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 80 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 45 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 35 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 50 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 70 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapasitor with the use of ZnO coated microsphere-based fiber-optic sensor - 30 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 60 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 40 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 85 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...
-
Temperature measurement of supercapacitor with the use of ZnO coated microsphere-based fiber-optic sensor - 55 Celsius degrees
Open Research DataApplication of a microsphere-based fiber-optic sensor with 200 nm zinc oxide (ZnO) coating, deposited by Atomic Layer Deposition (ALD) method, for temperature measurements of supercapasitor, is presented. Internal temperature of the supercapacitor is investigated in the range between 30°C and 90°C. The supercapacitor temperature was investigated using...