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Wyniki wyszukiwania dla: antenna measurement
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Multi-objective design optimization of antennas for reflection, size, and gain variability using kriging surrogates and generalized domain segmentation
PublikacjaCost-efficient multi-objective design optimization of antennas is presented. The framework exploits auxiliary data-driven surrogates, a multi-objective evolutionary algorithm for initial Pareto front identification, response correction techniques for design refinement, as well as generalized domain segmentation. The purpose of this last mechanism is to reduce the volume of the design space region that needs to be sampled in order...
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RSS-Based DoA Estimation Using ESPAR Antenna Radiation Patterns Spline Interpolation
PublikacjaIn this paper, it is shown how power pattern crosscorrelation (PPCC) algorithm, which relies on received signal strength (RSS) values recorded at electronically steerable parasitic array radiator (ESPAR) antenna output port, used for direction-of-arrival (DoA) estimation, can easily be improved by applying spline interpolation to radiation patterns recorded in the calibration phase of the DoA estimation process. The proposed method...
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Embedded device for indoor positioning of mobile terminals in ISM 2.4 GHz frequency band integrated with ESPAR antenna
PublikacjaIn the era of multifunctional mobile phones, wireless positioning is one of the most important branches of telecommunications development. This functionality is possible thanks to global positioning systems such as GPS, whose services are available to every average user. Global systems, however, suffer from their low accuracy in confined environments such as forests and building interiors. A popular...
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Radar technique in application of interlayer identification connections
PublikacjaOne of important issues in pavement construction is to ensure that layers applied directly one on top of the other make up a continuous whole and form an integral construction complex. An appropriate interlayer connection plays here significant role ensuring proper transmission of distortions generated by wheels of vehicles to lower layers and preventing water penetration between the layers. In case of damaged pavements where lack...
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An Efficient Framework For Fast Computer Aided Design of Microwave Circuits Based on the Higher-Order 3D Finite-Element Method
PublikacjaIn 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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Parallel Implementation of the Discrete Green's Function Formulation of the FDTD Method on a Multicore Central Processing Unit
PublikacjaParallel 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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Impact of Galileo Observations on the Position and Ambiguities Estimation of GNSS Reference Stations
PublikacjaDevelopment of Galileo navigation system has caused that it is increasingly used in various areas. One of the most important of them is precise positioning of the reference networks. In this paper we present the impact of Galileo observations on the differential precise positioning as well as ambiguities resolution of selected GNSS stations. We tested five different solutions: GPS-only, Galileo-only, GPS/Galileo, GPS/GLONASS and...
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Fading Modeling in Maritime Container Terminal Environments
PublikacjaIn this paper, an analytical model for slow and fast fading effects in maritime container terminals is derived, from fitting distributions to the results of measurements performed in an actual operational environment. The proposed model is composed of a set of equations, enabling to evaluate fading statistical distribution parameters for different system and environments conditions, as a function of frequency, base station antenna...
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Analiza właściwości emiterów LCR
PublikacjaOd wielu lat pojawiają się publikacje dotyczące konstrukcji emiterów służących do wypromieniowania energii pola elektromagnetycznego z układów, w których są wytwarzane impulsy prądowe o krótkim czasie trwania (rzędu ns lub µs) i znaczącej wartości szczytowej (rzędu MA). Tego rodzaju emitery nazywane są w języku angielskim Large Current Radiators (LCR). Budowa emitera LCR powinna zapewniać możliwie niewielką indukcyjność (rzędu...
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Electromagnetic Simulation with 3D FEM for Design Automation in 5G Era
PublikacjaElectromagnetic 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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Multi-Fidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
PublikacjaIn order to minimize the number of evaluations of high-fidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computational-efficient multi-fidelity local surrogate-model optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multi-fidelity coarse models and polynomial interpolation...
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Multimodal Particle Swarm Optimization with Phase Analysis to Solve Complex Equations of Electromagnetic Analysis
PublikacjaIn this paper, a new meta-heuristic method of finding roots and poles of a complex function of a complex variable is presented. The algorithm combines an efficient space exploration provided by the particle swarm optimization (PSO) and the classification of root and pole occurrences based on the phase analysis of the complex function. The method initially generates two uniformly distributed populations of particles on the complex...
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A Low-Profile 3-D Printable Metastructure for Performance Improvement of Aperture Antennas
PublikacjaIn order to increase the radiation performance of aperture-type antennas, this paper demonstrates a low-profile, planar, single-layer, three-dimensional (3-D) printable metastructure. The proposed hybridized metastructure is highly transparent as it is made out of novel hybrid meta-atoms having transmission coefficient magnitudes greater than -0.72 dB and fully complies with the near-field phase transformation principle. The hybridized...
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Acceleration of Electromagnetic Simulations on Reconfigurable FPGA Card
PublikacjaIn this contribution, the hardware acceleration of electromagnetic simulations on the reconfigurable field-programmable-gate-array (FPGA) card is presented. In the developed implementation of scientific computations, the matrix-assembly phase of the method of moments (MoM) is accelerated on the Xilinx Alveo U200 card. The computational method involves discretization of the frequency-domain mixed potential integral equation using...
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Laboratory investigation with subbottom parametric echosounder SES-2000 standard with an emphasis on reflected pure signals analysis
PublikacjaThe main goal of the paper is to describe correlations between measurements results of trials taken on Gulf of Gdańsk bottom sounded with parametric echosounder SES-2000 Standard and laboratory research where collected during survey sediments were measured. Stationary tests took place at Gdansk University of Technology where 30 meters long 1.8 meter deep and 3 meters wide water tank is located. Main lobe of antenna was directed...
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On EM-driven size reduction of antenna structures with explicit constraint handling
PublikacjaSimulation-driven miniaturization of antenna components is a challenging task mainly due to the presence of expensive constraints, evaluation of which involves full-wave electromagnetic (EM) analysis. The recommended approach is implicit constraint handling using penalty functions, which, however, requires a meticulous selection of penalty coefficients, instrumental in ensuring optimization process reliability. This paper proposes...
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High precision and accuracy using low cost GNSS receivers and supporting technologies
PublikacjaThis chapter focuses on methods and techniques of positioning, based on the highly accurate and precise Global Navigation Satellite System (GNSS), which are available at a relatively low price. In this context, a comparison of different positioning methods provided by the free and open source software (FOSS) package called RTKLIB is given. Other aspects related to price reduction are also considered, including availability and...
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Zero-Pole Approach in Microwave Passive Circuit Design
PublikacjaIn this thesis, optimization strategies for design of microwave passive structures including filters, couplers, antenna and impedance transformer and construction of various surroogate models utilized to fasten the design proces have been discussed. Direct and hybrid optimization methodologies including space mapping and multilevel algorithms combined with various surrogate models at different levels of fidelity have been utilized...
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Expedited Gradient-Based Design Closure of Antennas Using Variable-Resolution Simulations and Sparse Sensitivity Updates
PublikacjaNumerical optimization has been playing an increasingly important role in the design of contemporary antenna systems. Due to the shortage of design-ready theoretical models, optimization is mainly based on electromagnetic (EM) analysis, which tends to be costly. Numerous techniques have evolved to abate this cost, including surrogate-assisted frameworks for global optimization, or sparse sensitivity updates for speeding up local...
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Visible-light-driven lanthanide-organic-frameworks modified TiO2 photocatalysts utilizing up-conversion effect
PublikacjaHighly efficient and quite stable composite with core-shell-like architecture reported herein, responds to the challenge of sunlight-driven photocatalysts. The Ln(ndc)/TiO2 photocatalytic system comprises active lanthanide-carboxylate coordination networks (Nd, Er, Ho, and Tm as metal ions, and 2,6-naphthalene dicar-boxylic acid as the organic linker) and inert titanium dioxide and allow to convert incompatible visible radiation...
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Miniature reconfigurable antenna
PublikacjaThis work concerns the design of a miniature, low-profile reconfigurable antenna based on Huygens metamaterial sources for frequency f0 = 2.45 GHz. Two planar Huygens sources were designed consisting of near-field resonators. Sources are excited from a specially designed reconfigurable control system. Thanks to the two PIN diodes, the system can realize two cardioid radiation characteristics with...
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Low-Profile Interdigitated UHF RFID Tag Antenna for Metallic Objects
PublikacjaThis article presents a novel miniature interdigitated ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna that can be placed on metallic objects. The tag structure comprises two horizontal strip lines, each loaded with seven identical open stubs, and an integrated circuit (IC) chip connected directly to the feed lines in the middle of the structure. The perfect match to the IC chip’s impedance is realized...
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A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
PublikacjaSimulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially...
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Hourly GNSS-derived integrated moisture in the global tropics for the years 2001-2018
Dane BadawczeGlobal tropics are essential in formulating weather patterns and climate across various latitudes through atmospheric teleconnections. Since water vapour is an essential parameter in atmospheric convection and, thus, latent heat release, its tropical variability on different time scales is crucial in understanding weather and climate changes. The provided...
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Microfluidically Frequency-Reconfigurable Self-Quadruplexing Antenna Based on Substrate Integrated Square-Cavity
PublikacjaIn this article, a novel concept of self-quadruplexing tunable antenna (SQTA) enabled by microfluidic channels is investigated. The operating channels are either filled with air or dielectric liquids to enable frequency tunability. The proposed SQTA is implemented on the substrate-integrated square-cavity (SISC). A swastika-shaped slot is milled on the top-surface of the SISC to create four quarter-mode resonators. The resonators...
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Volumetric incorporation of NV diamond emitters in nanostructured F2 glass magneto-optical fiber probes
PublikacjaIntegration of optically-active diamond particles with glass fibers is a powerful method of scaling diamond's magnetic sensing functionality. We propose a novel approach for the integration of diamond particles containing nitrogen-vacancy centers directly into the fiber core. The core is fabricated by stacking the preform from 790 soft glass canes, drawn from a single rod dip-coated with submicron diamond particles suspended in...
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Wytwarzanie i charakterystyka cienkich warstw diamentowych na podłożach ze szkła kwarcowego, w szczególności na światłowodach włóknistych, dla zastosowań w sensorach optoelektronicznych
PublikacjaGłównym celem naukowym prac badawczych przeprowadzonych w rozprawie było wytwarzanie i modyfikacja funkcjonalności cienkich, przewodzących warstw diamentowych syntezowanych na podłożach optycznych. W ramach przeprowadzonych badań wytworzono szereg warstw diamentowych o specyficznych właściwościach optycznych i elektrycznych, mających na celu wykazanie możliwości wykorzystania takich struktur dla celów sensorycznych. Do poprawy...
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A new approach to design of weather disruption-tolerant wireless mesh networks
PublikacjaWireless Mesh Networks, offering transmission rates of 1–10 Gb/s per a millimeter-wave link (utilizing the 71–86 GHz band) seem to be a promising alternative to fiber optic backbone metropolitan area networks because of significantly lower costs of deployment and maintenance. However, despite providing high transmission rates in good weather conditions, high-frequency wireless links are very susceptible to weather disruptions....
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The Proposal to “Snapshot” Raim Method for Gnss Vessel Receivers Working in Poor Space Segment Geometry
PublikacjaNowadays, we can observe an increase in research on the use of small unmanned autonomous vessel (SUAV) to patrol and guiding critical areas including harbours. The proposal to “snapshot” RAIM (Receiver Autonomous Integrity Monitoring) method for GNSS receivers mounted on SUAV operating in poor space segment geometry is presented in the paper. Existing “snapshot” RAIM methods and algorithms which are used in practical applications...
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A compact spline-enhanced monopole antenna for broadband/multi-band and beyond UWB applications
PublikacjaIn this work, a compact monopole antenna for broadband/multi-band and beyond ultra- wideband (UWB) communication has been proposed. The structure is based on a spline-enhanced radiator with a broadband feed and a modified ground plane. Rigorous design optimization of the radiator has been performed in a two-stage framework where optimization of the structure with respect to electrical performance is followed by explicit miniaturization...
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Performance-driven yield optimization of high-frequency structures by kriging surrogates
PublikacjaUncertainty quantification is an important aspect of engineering design, as manufacturing toler-ances may affect the characteristics of the structure. Therefore, quantification of these effects is in-dispensable for adequate assessment of the design quality. Toward this end, statistical analysis is performed, for reliability reasons, using full-wave electromagnetic (EM) simulations. Still, the computational expenditures associated...
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A Compact Self-Hexaplexing Antenna Implemented on Substrate-Integrated Rectangular Cavity for Hexa-Band Applications
PublikacjaThis brief introduces a novel architecture of a compact self-hexaplexing antenna (SHA) implemented on a substrate-integrated rectangular cavity (SIRC) for hexa-band applications. The proposed SHA is configured by using an SIRC resonator, two Pi-shaped slots (PSSs), and six 50Ω microstrip feedlines. The PSSs are connected back-to-back and loaded on top of the SIRC resonator to produce six patch radiators (PRs). The PRs are excited...
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Data-Driven Surrogate-Assisted Optimization of Metamaterial-Based Filtenna Using Deep Learning
PublikacjaIn this work, a computationally efficient method based on data driven surrogate models is pro-posed for the design optimization procedure of a Frequency Selective Surface (FSS)-based filtering antenna (Filtenna). A Filtenna acts as a as module that simultaneously pre-filters unwanted sig-nals, and enhances the desired signals at the operating frequency. However, due to a typically large number of design variables of FSS unit elements,...
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Efficient knowledge-based optimization of expensive computational models using adaptive response correction
PublikacjaComputer simulation has become an indispensable tool in engineering design as they allow an accurate evaluation of the system performance. This is critical in order to carry out the design process in a reliable manner without costly prototyping and physical measurements. However, high-fidelity computer simulations are computationally expensive. This turns to be a fundamental bottleneck when it comes to design automation using numerical...
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Model Management for Low-Computational-Budget Simulation-Based Optimization of Antenna Structures Using Nature-Inspired Algorithms
PublikacjaThe primary objective of this study is investigation of the possibilities of accelerating nature-inspired optimization of antenna structures using multi-fidelity EM simulation models. The primary methodology developed to achieve acceleration is a model management scheme which the level of EM simulation fidelity using two criteria: the convergence status of the optimization algorithm, and relative quality of the individual designs...
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Greedy Multipoint Model-Order Reduction Technique for Fast Computation of Scattering Parameters of Electromagnetic Systems
PublikacjaThis paper attempts to develop a new automated multipoint model-order reduction (MOR) technique, based on matching moments of the system input–output function, which would be suited for fast and accurate computation of scattering parameters for electromagnetic (EM) systems over a wide frequency band. To this end, two questions are addressed. Firstly, the cost of the wideband reduced model generation is optimized by automating a...
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Reduced-Cost Two-Level Surrogate Antenna Modeling using Domain Confinement and Response Features
PublikacjaElectromagnetic (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)...
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Multi-objective design optimization of antenna structures using sequential domain patching with automated patch size deter-mination
PublikacjaIn this paper, a simple yet efficient and reliable technique for fully automated multi-objective design optimization of antenna structures using sequential domain patching (SDP) is discussed. The optimization procedure according to SDP is a two-step process: (i) obtaining the initial set of Pareto-optimal designs representing the best possible trade-offs between considered conflicting objectives, and (ii) Pareto set refinement...
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Cost-Efficient Surrogate Modeling of High-Frequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
PublikacjaSurrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)-driven design of high-frequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problem-specific knowledge....
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Rapid Design of 3D Reflectarray Antennas by Inverse Surrogate Modeling and Regularization
PublikacjaReflectarrays (RAs) exhibit important advantages over conventional antenna arrays, especially in terms of realizing pencil-beam patterns without the employment of the feeding networks. Unfortunately, microstrip RA implementations feature narrow bandwidths, and are severely affected by losses. A considerably improved performance can be achieved for RAs involving grounded dielectric layers, which are also easy to manufacture using...
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Multi-channel radio-over-fiber communication systems through modulation instability phenomenon
PublikacjaRecent advancements in Radio-over-Fiber (RoF) technology have positioned it as a promising solution for highcapacity wireless communications. This paper explores novel applications of RoF systems in enhancing phased array antenna (PAA) performance for multi-channel wireless communication applications through the modulation instability (MI) phenomenon. Utilizing fibers experiencing MI with varying group velocity dispersions (β2)...
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Exploring the Beam Squint Effects on Reflectarray Perfromance: A Comprehensive Analysis of the Specular and Scattered Reflection of the Unit Cell
PublikacjaIn this article, the phenomena of beam deviation in reflectarray is discussed. The radiation pattern of the unit cell, which plays a vital role in shaping the beam of the reflectarray, is analyzed by considering undesired specular and scattered reflections. These unwanted reflections adversely affect the pattern of the single unit cell, thereby reducing the overall performance of the reflectarray. To conduct our investigations,...
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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...
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Optimization of the Hardware Layer for IoT Systems using a Trust Region Method with Adaptive Forward Finite Differences
PublikacjaTrust-region (TR) algorithms represent a popular class of local optimization methods. Owing to straightforward setup and low computational cost, TR routines based on linear models determined using forward finite differences (FD) are often utilized for performance tuning of microwave and antenna components incorporated within the Internet of Things systems. Despite usefulness for design of complex structures, performance of TR methods...
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Spatio-temporal filtering for determination of common mode error in regional GNSS networks
PublikacjaThe spatial correlation between different stations for individual components in the regional GNSS networks seems to be significant. The mismodelling in satellite orbits, the Earth orientation parameters (EOP), largescale atmospheric effects or satellite antenna phase centre corrections can all cause the regionally correlated errors. This kind of GPS time series errors are referred to as common mode errors (CMEs). They are usually...
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Overview of planar antenna loading metamaterials for gain performance enhancement: the two decades of progress
PublikacjaMetamaterials (MTMs) are artificially engineered materials with unique electromagnetic properties not occurring in natural materials. MTMs have gained considerable attention owing to their exotic electromagnetic characteristics such as negative permittivity and permeability, thereby a negative refraction index. These extraordinary properties enable many practical applications such as super-lenses, and cloaking technology, and are...
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Optimization-Based High-Frequency Circuit Miniaturization through Implicit and Explicit Constraint Handling: Recent Advances
PublikacjaMiniaturization trends in high-frequency electronics have led to accommodation challenges in the integration of the corresponding components. Size reduction thereof has become a practical necessity. At the same time, the increasing performance demands imposed on electronic systems remain in conflict with component miniaturization. On the practical side, the challenges related to handling design constraints are aggravated by the...
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On Improved-Reliability Design Optimization of High-Frequency Structures Using Local Search Algorithms
PublikacjaThe role of numerical optimization has been continuously growing in the design of high-frequency structures, including microwave and antenna components. At the same time, accurate evaluation of electrical characteristics necessitates full-wave electromagnetic (EM) analysis, which is CPU intensive, especially for complex systems. As rigorous optimization routines involve repetitive EM simulations, the associated cost may be significant....
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RSS-Based DoA Estimation Using ESPAR Antenna for V2X Applications in 802.11p Frequency Band
PublikacjaIn this paper, we have proposed direction-of arrival (DoA) estimation of incoming signals for V2X applications in 802. 11p frequency band, based on recording of received signal strength (RSS) at electronically steerable parasitic array radiator (ESPAR) antenna's output port. The motivation of the work was to prove that ESPAR antenna used to increase connectivity and security in V2X communication can...
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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
PublikacjaTwo 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...