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Machine-Learning-Powered EM-Based Framework for Efficient and Reliable Design of Low Scattering Metasurfaces
PublicationPopularity of metasurfaces has been continuously growing due to their attractive properties including the ability to effectively manipulate electromagnetic (EM) waves. Metasurfaces comprise optimized geometries of unit cells arranged as a periodic lattice to obtain a desired EM response. One of their emerging application areas is the stealth technology, in particular, realization of radar cross section (RCS) reduction. Despite...
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Compact Electromagnetic Lens Antennas Using Cascaded Metasurfaces for Gain Enhancement and Beam Steering Applications
PublicationElectromagnetic (EM) lens antenna designs using cascaded metasurfaces for gain enhancement and beam steering applications are proposed. Two different lens aperture designs are proposed and populated with aperiodic unit cells of size 0.2λo × 0.2λo. In lens Design 1, the unit cells of different phases are distributed in concentric circular zones, whereas in lens Design 2, the unit cells of different phases are distributed in vertical...
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Modulated crystal structures - periodicity in more than three dimensions
PublicationThe initial definition of a crystal was that it is an object with flat faces. When diffraction studies were developed it turned out that crystal consists of a highly ordered particles and it is possible to isolate a small unique part of their structure - a unit cell - and the definition has been changed to rely on this fact. Nowadays by a crystal we mean any solid having an essentially discrete diffraction diagram. It is because...
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Isolation Number versus Domination Number of Trees
PublicationIf G=(VG,EG) is a graph of order n, we call S⊆VG an isolating set if the graph induced by VG−NG[S] contains no edges. The minimum cardinality of an isolating set of G is called the isolation number of G, and it is denoted by ι(G). It is known that ι(G)≤n3 and the bound is sharp. A subset S⊆VG is called dominating in G if NG[S]=VG. The minimum cardinality of a dominating set of G is the domination number, and it is denoted by γ(G)....
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublicationAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
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Center for Scientific and Technical Information - Library Services for Business and Science at Wroclaw University of Technology
PublicationWroclaw University of Technology is situated in Lower Silesia – the dynamically developing region of Poland. Focusing on adopting its own offer to the market needs had been selected as a strategy. Due to that, a synergy effect has been achieved with the development of segments strategic for the region. The University is strongly oriented to cooperation with the economy and industry. One of the key initiatives was establishment...
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Operation evaluation method for marine turbine combustion engines in terms of energetics
PublicationAn evaluation proposal (quantitative determination) of an y combustion turbine engine operation has been presented , wherein the impact energy occurs at a given time due to Energy conversion. The fact has been taken into account that in this type of internal combustion engines the energy conversion occurs first in the combustion chambers and in the spaces between the blade of the turbine engine. It was assumed that in the combustion...
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Longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices
PublicationThis paper presents investigations of longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices. The proposed junction is formed as a quasi periodic arrangement of N unit cells. Each unit cell is realized as a cascade of short cylindrical ferrite coupled lines with reactance circuit composed of series capacitors and parallel inductors. The left-handed cylindrical junction with π/4...
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Compensation of pressure peaks in pwk-type hydraulic pumps
Publicationhydraulic axial pumps equipped with cam-driven commutation unit (pwk pumps) proved their high efficiency up to 55 mpa and ability to work self-sucking, even at high speed. displacement of pwk pump may easily be changed by moving its control cam. full discharge from hydrostatic forces makes such control possible by direct action of a low-energy actuator like proportional electromagnet or stepping motor. that eliminates heavy and...
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Technique for reducing erosion in large-scale circulating fluidized bed units
PublicationThis paper presents a methodology, implemented for a real industrial-scale circulating fluidized bed boiler, to mitigate the risk of heating surfaces exposed to an intensive particle erosion process. For this purpose, a machine learning algorithm was developed to support the boiler reliability management process. Having a tool that can help mitigate the risk of uncontrolled power unit failure without expensive and technically complex...
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Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes
PublicationIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
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Testing Stability of Digital Filters Using Multimodal Particle Swarm Optimization with Phase Analysis
PublicationIn this paper, a novel meta-heuristic method for evaluation of digital filter stability is presented. The proposed method is very general because it allows one to evaluate stability of systems whose characteristic equations are not based on polynomials. The method combines an efficient evolutionary algorithm represented by the particle swarm optimization and the phase analysis of a complex function in the characteristic equation....
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Enhanced Remote Control Providing Medical Functionalities
PublicationThis paper presents the enhanced remote control and its role in pervasive healthcare in the home. The device was equipped with health-related measurement modules and a message-processing unit. Preliminary results are presented for monitoring of a pulse, hand tremors, grip forces, and for self evaluation procedures. The interaction of the device with the smart environment is presented and discussed.
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Mathemathical model of radial passive magnetic bearing
PublicationIn the article mathematical radial model of passive magnetic bearings to ocean engineering units has been presented. The units application in underwater thrusters should increase propulsion systems durability and gives lower maintenance costs. The rotor of electric motor is hanging in magnetic field taken from radial passive magnetic bearings. However axial direction maintenance must be controlled with electromagnets and their...
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Fate and significance of phthalates and bisphenol A in liquid by-products generated during municipal solid waste mechanical-biological pre-treatment and disposal
PublicationSamples of liquid by-products generated by municipal solid waste plants (MSWPs) were tested for the presence of phthalates (PAEs) and bisphenol A (BPA). The results indicated that the wastewater generated during mechanical (sorting unit - SU) and biological (composting unit - CU) pre-treatment (MBT) of residual (mixed) solid waste is a significant source of these compounds. The concentrations of PAEs (up to 32222 lg/L) and BPA...
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Acoustic imaging of selected areas of Gdansk Bay with the aid of parametric echosounder and side-scan sonar
PublicationThe article presents and analyses the data recorded during sounding of the Gdansk Bay seabed with the aid of a parametric echosounder and a side-scan sonar. The accuracy of seabed structure examination, as a condition for obtaining valuable results, requires correct configuration of echolocation devices and proper calibration of peripheral devices, such as the survey unit geographical position sensor – GPS, the navigation unit,...
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Stability analysis of interconnected discrete-time fractional-order LTI state-space systems
PublicationIn this paper, a stability analysis of interconnected discrete-time fractional-order (FO) linear time-invariant (LTI) state-space systems is presented. A new system is formed by interconnecting given FO systems using cascade, feedback, parallel interconnections. The stability requirement for such a system is that all zeros of a non-polynomial characteristic equation must be within the unit circle on the complex z-plane. The obtained...
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Wskaźnik przedsiębiorczości w jednostkach terytorialnych Polski – zróżnicowanie w czasie i przestrzeni
PublicationPrzedmiotem artykułu jest analiza zjawiska prowadzenia działalności gospodarczej przez osoby fizyczne, mierzonego poprzez wskaźnik liczby tych osób na 100 osób w wieku produkcyjnym. Wskaźnik ten nazywany jest nieraz wskaźnikiem przedsiębiorczości, mimo, że mierzy tylko jeden z jej przejawów. Badania prowadzono w układzie podregionów, powiatów i gmin (według ich rodzaju, z wyodrębnieniem miast w gminach miejsko-wiejskich). Celem...
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Research and Analysis of Accuracy of Location Estimation in Inertial Navigation System
PublicationIn the article the research and analysis of digital signal processing and its influence on accuracy of location estimation in developed inertial navigation system was presented. The purpose of the system is to localize moving people in indoor environment. During research a measuring unit for recording selected movement parameters was made. In the article were also described author’s inertial navigation algorithms.
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AUTOMATED SYSTEM FOR FLUCTUATION ENHANCED GAS SENSING
PublicationResistance gas sensors exhibit random phenomena (resistance noise) which can be utilized to improve gas sensitivity and selectivity. That new emerging technique has to be investigated to recognize optimal parameters for gas detection. It means that a measurement system has to have ability of numerous parameters adjustment (e.g., sampling frequency, heater voltage, polarization current, voltage noise amplification). That fact induced...
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Synthesis, crystal structure and cytotoxic activity of ruthenium(II) piano-stool complex with N,N-chelating ligand
PublicationA mononuclear compound of the general formula [(η6-p-cymene)RuIICl(2,2′-PyBIm)]PF6 has been synthesized from a bidentate N,N-donor ligand, viz. 2,-(2′-pyridyl)benzimidazole (2,2′-PyBIm) and the corresponding chloro-complex [(η6-p-cymene)Ru(μ-Cl)Cl]2 (precursor). The isolated coordination compound was characterized by IR, UV–vis and 1H, 13C NMR spectroscopies. The single crystal X-ray analysis of the complex reveals that the asymmetric...
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Simulation of the response of base-isolated buildings under earthquake excitations considering soil flexibility
PublicationThe accurate analysis of the seismic response of isolated structures requires the incorporation of the flexibility of supporting soil. However, it is often customary to idealize the soil as rigid during the analysis of such structures. In the present paper, seismic response time history analyses of base-isolated buildings modelled as single degree-of-freedom (SDOF) and multi degree-of-freedom (MDOF) systems with linear and nonlinear...
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Energy storage device based on flywheel, power converters and Simulink real-time
PublicationThis electronic document is a “live” template and already defines the components of your paper [title, text, heads, etc.] in its style sheet. Paper presents information on Energy Storage Device based on Flywheel and bi-directional IGBT Power Converters – designed for LINTE^2 laboratory owned by Gdansk University of Technology in Poland. Paper is divided into four sections. First section of the paper provides introductory information...
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Cooperation of ORC installation with a gas boiler as a perspective co-generation system for households
PublicationThis paper reports tests of an innovative micro-CHP unit prototype, consisting of a traditional gas boiler and organic Rankine cycle (ORC), which incorporates original system components such as an axial vapour microturbine, evaporator and condenser. The system co-generates heat and electricity for a single household or a group of households. Electricity is only a by-product during production of heat. While testing the prototype,...
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How to evaluate methods used in chemical laboratories in terms of the total chemical risk? – a ChlorTox Scale
PublicationReliable assessment of the health and environmental risk associated with the use of chemicals is critical to ob- jectively evaluate the greenness and whiteness of an analytical method. An objective and useful way of risk assessment should take into account all the relevant properties of used substances, their actual amounts needed for application of the method, and quantify the assessment result using a standardized unit. This...
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On trees with double domination number equal to total domination number plus one
PublicationA total dominating set of a graph G is a set D of vertices of G such that every vertex of G has a neighbor in D. A vertex of a graph is said to dominate itself and all of its neighbors. A double dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D. The total (double, respectively) domination number of a graph G is the minimum cardinality of a total (double,...
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On trees with double domination number equal to 2-domination number plus one
PublicationA vertex of a graph is said to dominate itself and all of its neighbors. A subset D subseteq V(G) is a 2-dominating set of G if every vertex of V(G)D is dominated by at least two vertices of D, while it is a double dominating set of G if every vertex of G is dominated by at least two vertices of D. The 2-domination (double domination, respectively) number of a graph G is the minimum cardinality of a 2-dominating (double dominating,...
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Transcriptomic landscape of blood platelets in healthy donors
PublicationBlood platelet RNA-sequencing is increasingly used among the scientific community. Aberrant platelet transcriptome is common in cancer or cardiovascular disease, but reference data on platelet RNA content in healthy individuals are scarce and merit complex investigation. We sought to explore the dynamics of platelet transcriptome. Datasets from 204 healthy donors were used for the analysis of splice variants, particularly with...
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Transcriptomic landscape of blood platelets in healthy donors
PublicationBACKGROUND Blood platelet RNA-sequencing is increasingly used among the scientific community. Aberrant platelet transcriptome is common in cancer or cardiovascular disease, but reference data on platelet RNA content in healthy individuals are scarce and merit complex investigation. METHODS We sought to explore the dynamics of platelet transcriptome. Datasets from 204 healthy donors were used for the analysis of splice variants,...
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Design and investigations of the ethanol microturbine
PublicationThe paper presents the results of the design analysis and experimental investigations of the microturbine set consisting of the microturbine with partial admission and permanent magnet generator. The microturbine was designed for operation with the vapour of ethanol as a working fluid. Microturbine unit was tested for different parameters of the working fluid and varying the electrical load. The examples and the comparison between...
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Steam turbines governors in power system restoration process
PublicationThe paper discusses problems related to electric power system restoration process. The turbine controller operating mode influence in small subsystem is analyzed. There are considered abilities, advantages and drawbacks of the controller's two operating modes: power control and speed (frequen-cy) control, to rebuild electric power system from a single generating unit to a few parallel running generators.
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Research of electric drive systems with real time software configurable control
PublicationПредмет исследования. Представлен учебно-лабораторный стенд для исследования систем управления элек- троприводами. Стенд используется для обучения студентов системам управления электроприводами и предна- значен для повышения эффективности усвоения материала. Метод. В основу предлагаемого решения положен метод взаимного нагружения электрических машин, питаемых от силовых преобразователей с общим звеном постоянного тока. Это позволяет...
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Bondage number of grid graphs
PublicationThe bondage number b(G) of a nonempty graph G is the cardinality of a smallest set of edges whose removal from G results in a graph with domination number greater than the domination number of G. Here we study the bondage number of some grid-like graphs. In this sense, we obtain some bounds or exact values of the bondage number of some strong product and direct product of two paths.
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2-Coloring number revisited
Publication2-Coloring number is a parameter, which is often used in the literature to bound the game chromatic number and other related parameters. However, this parameter has not been precisely studied before. In this paper we aim to fill this gap. In particular we show that the approximation of the game chromatic number by the 2-coloring number can be very poor for many graphs. Additionally we prove that the 2-coloring number may grow...
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Bounds on isolated scattering number
PublicationThe isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.
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Bounds on isolated scattering number
PublicationThe isolated scattering number is a parameter that measures the vulnerability of networks. This measure is bounded by formulas de- pending on the independence number. We present new bounds on the isolated scattering number that can be calculated in polynomial time.
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Navier number and transition to turbulence
PublicationThe motivation behind this article is to explain a role of the Navier number (Na -dimensionless slip-length) in prediction of closures for laminar to turbulent transition undergoing via eddies detachment from the slip layer in nano-cannals. Additionally the role of the Navier number Na in universal modeling of phenomenon of enhanced mass flow rate reported in micro- and nano-channels has been explained. The Na number should be...
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Equitable and semi-equitable coloring of cubic graphs and its application in batch scheduling
PublicationIn the paper we consider the problems of equitable and semi-equitable coloring of vertices of cubic graphs. We show that in contrast to the equitable coloring, which is easy, the problem of semi-equitable coloring is NP- complete within a broad spectrum of graph parameters. This affects the complexity of batch scheduling of unit-length jobs with cubic incompatibility graph on three uniform processors to minimize...
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Investigation of the influence of capilary effect on operation of the loop heat pipe
PublicationIn the paper presented are studies on the inestigation of the capillary forces effect inducted in the porous structure of a loop heat pipe using water and ethanol ad test fluids. The potential application of such effects is for example in the evaporator of the domestic micro-CHP unit, where the reduction of pumping power could be obtained. Preliminary analysis of the results indicates water as having the best potential for developing...
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Intramolecular interactions in crystals of tris(2,6-diisopropylphenoxy)silanethiol and its sodium salts
PublicationHydrolytically stable tris(2,6-diisopropylphenoxy)silanethiol has been obtained and reacted with sodium. Solid state interactions within and between the molecules of tris(2,6-diisopropylphenoxy)silanethiol including S-H---π-interactions between the S-H unit and the π-system of the arene have been analyzed. The interactions are documented by X-ray diffraction and FT-IR spectroscopy.
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High Performance Tubular Heat Exchanger with Minijet Heat Transfer Enhancement
PublicationIn the paper, the original cylindrical heat exchanger with minijets (MJHE) was introduced. The systematic experimental analysis of the prototype heat exchanger was described with special attention paid to such parameters as the heat transfer effectiveness, heat transfer rates, overall heat transfer coefficients, and pressure drop. The heat transfer coefficients were determined based on Wilson plot method, the most suitable approach...
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Natural convective heat transfer from isothermal cuboids
PublicationThe paper presents results of theoretical and experimental investigations of the convective heat transfer from isothermal cuboid. The analytical solution was performed taking into account complete boundary layer length and the manner of its propagation around isothermal cuboid. It arises at horizontal bottom surface and grows on vertical lateral surface of the block. After changing its direction, the boundary layer occurs above...
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Using wavelet techniques for multibeam sonar bathymetry data compression
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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On the compression of multibeam sonar raw bathymetry data
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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A memory efficient and fast sparse matrix vector product on a Gpu
PublicationThis paper proposes a new sparse matrix storage format which allows an efficient implementation of a sparse matrix vector product on a Fermi Graphics Processing Unit (GPU). Unlike previous formats it has both low memory footprint and good throughput. The new format, which we call Sliced ELLR-T has been designed specifically for accelerating the iterative solution of a large sparse and complex-valued system of linear equations arising...
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Proposal of a mobile medical waste incinerator with automatic waste feeder and heat recovery system
PublicationThe paper presents and discusses the issue of medical waste (including hazardous ones) and their proper management. Inappropriate handling of infectious medical waste directly endangers the human being health and the environment. Infectious waste must therefore be properly disposed of – one of the most commonly used methods is the thermal treatment in the incinerators tailored for this purpose. During designing an incinerator unit,...
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Proposal of a Mobile Medical Waste Incinerator with Application of Automatic Waste Feeder and Heat Recovery System as a Novelty in Poland
PublicationThe paper presents and discusses the issues of medical waste (including hazardous ones) and the problems regarding their proper management in Poland. Inappropriate handling of infectious medical waste directly endangers human health and the environment. Infectious waste must be properly disposed of—in practice, the only method of their disposal available in Poland is a thermal treatment in the incinerators tailored for this purpose....
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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...
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Implementation of FDTD-compatible Green's function on heterogeneous CPU-GPU parallel processing system
PublicationThis paper presents an implementation of the FDTD-compatible Green's function on a heterogeneous parallel processing system. The developed implementation simultaneously utilizes computational power of the central processing unit (CPU) and the graphics processing unit (GPU) to the computational tasks best suited to each architecture. Recently, closed-form expression for this discrete Green's function (DGF) was derived, which facilitates...
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An Optimized Ka-Band Low Profile Dual-Polarized Transmitarray Antenna With 2D Beam Switching
PublicationThis article presents an optimized dual-polarized transmitarray antenna (TA) designed for MIMO applications at the Ka-band, capable of switching beams in two directions. The antenna aperture uses a small unit cell with three layers of Taconic RF-35 dielectric substrates, which can be easily fabricated using PCB technology. The unit cell achieved a 360-degree phase shift and a transmission magnitude exceeding –0.4 dB at 28 GHz....