Weryfikacja:
Politechnika Gdańska
Rok  Punkty  Lista 

2019  140  MNiSW 2019 
2017  35  A 
2016  30  A 
2015  30  A 
2014  35  A 
2013  35  A 
2011  30  A 
2008  32  A 
Polityki wydawnicze:
Brak danych
ISSN:
15361225
Prace opublikowane w tym czasopiśmie
Filtry
wszystkich: 43
Katalog Czasopism
2019

A Geometrically Simple Compact Wideband Circularly Polarized Antenna
PublikacjaA compact broadband wideslot circular polarization (CP) antenna is proposed. An inverted Lshape parasitic strip at the open end of a microstrip line extension and a slot modification is applied to attain wideband CP. The advantage of this technique is simplicity which makes it readily redesignable for different frequency bands. To demonstrate the concept, three designs working at different frequencies are obtained. The redesign...

A Wideband Corrugated Ridged Horn Antenna with Enhanced Gain and Stable Phase Center for X and KuBand Applications
PublikacjaIn this letter, a structure and design procedure of a novel doubleflared conical horn antenna with an improved gain and a stable phase center is presented. The antenna incorporates a hybrid ridged and corrugated structure. A doubleridged section is responsible for ensuring a wideband operation, whereas the corrugated section supports the hybrid mode. The antenna impedance bandwidth (VSWR < 2) is 6 GHz to 20 GHz. Excellent performance...

Reliable MultiStage Optimization of Antennas for Multiple Performance Figures in HighlyDimensional Parameter Spaces
PublikacjaDesign of modern antenna structures needs to account for multiple performance figures and geometrical constraints. Fulfillment of these calls for the development of complex topologies described by a large number of parameters. EMdriven tuning of such designs is mandatory yet immensely challenging. In this letter, a new framework for multistage design optimization of multidimensional antennas with respect to several performance...

RSSBased DoA Estimation for ESPAR Antennas Using Support Vector Machine
PublikacjaIn this letter, it is shown how directionofarrival (DoA) estimation for electronically steerable parasitic array radiator (ESPAR) antennas, which are designed to be integrated within wireless sensor network nodes, can be improved by applying support vector classification approach to received signal strength (RSS) values recorded at an antenna's output port. The proposed method relies on ESPAR antenna's radiation patterns measured...
2018

A Broadband Circularly Polarized WideSlot Antenna with a Miniaturized Footprint
PublikacjaThis letter presents a novel and simple feeding technique for exciting orthogonal components in a wideslot antenna. In this technique, a rectangular bracketshape parasitic strip is placed at the open end of the straight microstrip line to excite the fundamental horizontal and vertical components of the circular polarization (CP). The proposed technique—when employed in conjunction with the asymmetrical geometry of coplanar waveguide...

Block Conjugate Gradient Method with Multilevel Preconditioning and GPU Acceleration for FEM Problems in Electromagnetics
PublikacjaIn this paper a GPUaccelerated block conjugate gradient solver with multilevel preconditioning is presented for solving large system of sparse equations with multiple right handsides (RHSs) which arise in the finiteelement analysis of electromagnetic problems. We demonstrate that blocking reduces the time to solution significantly and allows for better utilization of the computing power of GPUs, especially when the system matrix...

Expedited Design Closure of Antennas By Means Of TrustRegionBased Adaptive Response Scaling
PublikacjaIn the letter, a reliable procedure for expedited design optimization of antenna structures by means of trustregion adaptive response scaling (TRARS) is proposed. The presented approach exploits twolevel electromagnetic (EM) simulation models. A predicted highfidelity model response is obtained by applying nonlinear frequency and amplitude correction to the lowfidelity model. The surrogate created this way is iteratively rebuilt...

Implicit Space Mapping for VariableFidelity EMDriven Design of Compact Circuits
PublikacjaSpace mapping (SM) belongs to the most successful surrogatebased optimization (SBO) methods in microwave engineering. Among available SM variations, implicit SM (ISM) is particularly attractive due to its simplicity and separation of extractable surrogate model parameters and design variables of the circuit/system at hand. Unlike other SM approaches, ISM exploits a set of preassigned parameters to align the surrogate with the...

Model Correction and Optimization Framework for Expedited EMDriven SurrogateAssisted Design of Compact Antennas
PublikacjaDesign of compact antennas is a numerically challenging process that heavily relies on electromagnetic (EM) simulations and numerical optimization algorithms. For reliability of simulation results, EM models of small radiators often include connectors which—despite being components with fixed dimensions—significantly contribute to evaluation cost. In this letter, a response correction method for antenna models without connector,...

Rapid design closure of linear microstrip antenna array apertures using response features
PublikacjaA simple yet reliable approach to a rapid design closure of linear antenna array apertures at the electromagnetic (EM)simulation level is proposed. Our methodology exploits an underlying array factor (AF) model suitably corrected by means of characteristic points (angles and levels) of the radiation pattern of the EM model of the antenna array aperture. This conveniently allows for controlling both the side lobe levels...

Reducedcost constrained miniaturization of wideband antennas using improved trustregion gradient search with repair step
PublikacjaIn the letter, an improved algorithm for electromagnetic (EM)driven size reduction of wideband antennas is proposed. Our methodology utilizes variablefidelity EM simulation models, auxiliary polynomial regression surrogates, as well as multipoint response correction. The constraint handling is implicit, using penalty functions. The core optimization algorithm is a trustregion gradient search with a repair step added in order...

Reliable Greedy Multipoint ModelOrder Reduction Techniques for FiniteElement Analysis
PublikacjaA new greedy multipoint modelorder reduction algorithm for fast frequencydomain finiteelement method simulations of electromagnetic problems is proposed. The location of the expansion points and the size of the projection basis are determined based on a rigorous error estimator. Compared to previous multipoint methods, the quality of the error estimator is significantly improved by ensuring the orthogonality of the projection...

RSSbased DoA Estimation Using ESPAR Antennas and Interpolated Radiation Patterns
PublikacjaIn this letter, it is shown how an algorithm, which employs received signal strength (RSS) values in order to estimate directionofarrival (DoA) of impinging signals in wireless sensor network (WSN) nodes equipped with electronically steerable parasitic array radiator (ESPAR) antennas, can easily be improved by applying an interpolation algorithm to radiation patterns recorded in the calibration phase of the DoA estimation process....

Uniform sampling in constrained domains for lowcost surrogate modeling of antenna input characteristics
PublikacjaIn this letter, a design of experiments technique that permits uniform sampling in constrained domains is proposed. The discussed method is applied to generate training data for construction of fast replacement models (surrogates) of antenna input characteristics. The modeling process is designoriented with the surrogate domain spanned by a set of reference designs optimized with respect to the performance figures and/or operating...
2017

Objective relaxation algorithm for reliable simulationdriven size reduction of antenna structure
PublikacjaThis letter investigates reliable size reduction of antennas through electromagneticdriven optimization. It is demonstrated that conventional formulation of the design task by direct footprint miniaturization with imposing constraints on electrical performance parameters may not lead to optimum results. The reason is that—in a typical antenna structure—only a few geometry parameters explicitly determine the antenna footprint,...

Pareto Ranking Bisection Algorithm for Expedited MultiObjective Optimization of Antenna Structures
PublikacjaThe purpose of this letter is introduction of a novel methodology for expedited multiobjective design of antenna structures. The key component of the presented approach is fast identification of the initial representation of the Pareto front (i.e., a set of design representing the best possible tradeoffs between conflicting objectives) using a Paretoranking bisection algorithm. The algorithm finds a discrete set of Paretooptimal...

Simple 2D DirectionofArrival Estimation Using an ESPAR Antenna
PublikacjaIn this letter, it has been shown how an electronically steerable parasitic array radiator (ESPAR) antenna can be used for 2D directionofarrival (DoA) estimation employing received signal strength (RSS) values only. The proposed approach relies on changes in RSS values recorded at the antenna output port observed for different vertical and horizontal directions, while antenna’s main beam sweeps 360° area around the ESPAR antenna. Based...
2016

A structure and simulationdriven design of compact CPWfed UWB antenna
PublikacjaIn this letter, a structure of a miniaturized ultrawideband CPWfed antenna and its design procedure are presented. The antenna is a modified version of the design previously proposed in the literature, with additional degrees of freedom introduced in order to improve the structure flexibility. The small size is achieved by executing a rigorous optimization procedure that consists of two stages: (i) smart random search carried...

Costefficient design optimization of compact patch antennas with improved bandwidth
PublikacjaIn this letter, a surrogateassisted optimization procedure for fast design of compact patch antennas with enhanced bandwidth is presented. The procedure aims at addressing a fundamental challenge of the design of antenna structures with complex topologies, which is simultaneous adjustment of numerous geometry parameters. The latter is necessary in order to find a truly optimum design and cannot be executedat the level of highfidelity...

Fast simulationdriven design optimization of UWB bandnotch antennas
PublikacjaIn this letter, a simple yet reliable and automated methodology for rapid design optimization of ultrawideband (UWB) bandnotch antennas is presented. Our approach is a twostage procedure with the first stage focused on the design of the antenna itself, and the secondstage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the bandnotch in the desired frequency range. For the...

LowCost DataDriven Surrogate Modeling of Antenna Structures by Constrained Sampling
PublikacjaFullwave electromagnetic (EM) analysis has become one of the major design tools for contemporary antenna structures. Although reliable, it is computationally expensive which makes automated simulationdriven antenna design (e.g., parametric optimization) difficult. This difficulty can be alleviated by utilization of fast and accurate replacement models (surrogates). Unfortunately, conventional datadriven modeling of antennas...

Multiobjective antenna design by means of sequential domain patching
PublikacjaA simple yet robust methodology for rapid multiobjective design optimization of antenna structures has been presented. The key component of our approach is sequential domain patching of the design space which is a stencilbased search that aims at creating a path that connects the extreme Paretooptimal designs, obtained by means of singleobjective optimization runs. The patching process yields the initial approximation of the...

On ReducedCost DesignOriented Constrained Surrogate Modeling of Antenna Structures
PublikacjaDesign of contemporary antenna structures heavily relies on fullwave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional datadriven...

Rapid EMdriven antenna dimension scaling through inverse modeling
PublikacjaIn this letter, a computationally feasible technique for dimension scaling of antenna structures is introduced. The proposed methodology is based on inverse surrogate modeling where the geometry parameters of the antenna structure of interest are explicitly related to the operating frequency. The surrogate model is identified based on a few antenna designs optimized for selected reference frequencies. For the sake of computational...

SingleAnchor Indoor Localization Using ESPAR Antenna
PublikacjaIn this paper a new singleanchor indoor localization concept employing Electronically Steerable Parasitic Array Radiator (ESPAR) antenna has been proposed. The new concept uses a simple fingerprinting algorithm adopted to work with directional main beam and narrow minimum radiation patterns of ESPAR antenna that scans 360° area around the base station, while the signal strength received from a mobile terminal is being recorded...
2015

A New Expression for the 3D Dyadic FDTDCompatible Green's Function Based on Multidimensional ZTransform
PublikacjaIn this letter, a new analytic expression for the timedomain discrete Green's function (DGF) is derived for the 3D finitedifference timedomain (FDTD) grid. The derivation employs the multidimensional Ztransform and the impulse response of the discretized scalar wave equation (i.e., scalar DGF). The derived DGF expression involves elementary functions only and requires the implementation of a single function in the multipleprecision...

Automated Reduced Model Order Selection
PublikacjaThis letter proposes to automate generation of reducedorder models used for accelerated parameter computation by applying a posteriori model error estimators. So far,a posteriori error estimators were used in Reduced Basis Method (RBM) and Proper Orthogonal Decomposition (POD) to select frequency points at which basis vectors are generated. This letter shows how a posteriori error estimators can be applied to automatically select...

Design of a Planar UWB Dipole Antenna with an Integrated Balun Using SurrogateBased Optimization
PublikacjaA design of an ultrawideband (UWB) antenna with an integrated balun is presented. A fully planar balun configuration interfacing the microstrip input of the structure to the coplanar stripline (CPS) input of the dipole antenna is introduced. The electromagnetic (EM) model of the structure of interest includes the dipole, the balun, and the microstrip input to account for coupling and radiation effects over the UWB band. The EM...

Fast EMdriven size reduction of antenna structures by means of adjoint sensitivities and trust regions
PublikacjaIn this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using highfidelity EM simulation. In order...

Fast MultiObjective Optimization of NarrowBand Antennas Using RSA Models and Design Space Reduction
PublikacjaComputationally efficient technique for multiobjective design optimization of narrowband antennas is presented. In our approach, the corrected lowfidelity antenna model (obtained through coarsediscretization EM simulations) is enhanced using frequency scaling and response correction, sampled, and utilized to obtain a fast response surface approximation (RSA) antenna surrogate. The RSA model is constructed in the reduced design space....

SimulationBased Design of Microstrip Linear Antenna Arrays Using Fast Radiation Response Surrogates
PublikacjaFast yet accurate technique for simulationbased design of linear arrays of microstrip patch antennas is presented. Our technique includes: (i) optimization of the corrected array factor of the antenna array under design for a phase excitation taper resulting in reduced side lobes; (ii) simulationdriven optimization of the array element for element dimensions resulting in matching at and about operational frequency, and (iii)...

Structure and computationallyefficient simulationdriven design of compact UWB monopole antenna
PublikacjaIn this letter, a structure of a small ultrawideband (UWB) monopole antenna, its design optimization procedure as well as experimental validation are presented. According to our approach, antenna compactness is achieved by means of a meander line for current path enlargement as well as the two parameterized slits providing additional degrees of freedom that help to ensure good impedance matching. For the sake of reliability, the...
2014

Analytical Expression for the TimeDomain Discrete Green's Function of a Plane Wave Propagating in the 2D FDTD Grid
PublikacjaIn this letter, a new closedform expression for the timedomain discrete Green's function (DGF) of a plane wave propagating in the 2D finitedifference timedomain (FDTD) grid is derived. For the sake of its verification, the timedomain implementation of the analytic field propagator (AFP) technique was developed for the plane wave injection in 2D totalfield/scatteredfield (TFSF) FDTD simulations. Such an implementation of...

Expedited design of microstrip antenna subarrays using surrogatebased optimization
PublikacjaComputationally efficient simulationdriven design of microstrip antenna subarrays is presented. The proposed design approach aims at simultaneous adjustment of all relevant geometry parameters of the subarray, which allows us to take into account the effect of the feeding network on the subarray radiation pattern (in particular, the side lobe level, SLL). In order to handle a large number of variables involved in the design process,...

Expedited EMdriven multiobjective antenna design in highlydimensional parameter spaces
PublikacjaA technique for lowcost multiobjective optimization of antennas in highlydimensional parameter spaces is presented. The optimization procedure is expedited by exploiting fast surrogate models, including coarsediscretization EM antenna simulations and response surface approximations (RSA). The latter is utilized to yield an initial set of Pareto nondominated designs which are further refined using response correction methods....
2013

Hybrid Technique Combining the FDTD Method and Its Convolution Formulation Based on the Discrete Green's Function
PublikacjaIn this letter, a technique combining the finitedifference timedomain (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...
2012

Accuracy, Memory and Speed Strategies in GPUbased FiniteElement MatrixGeneration
PublikacjaThis paper presents strategies on how to optimize GPUbased finiteelement matrixgeneration that occurs in the finiteelement method (FEM) using higher order curvilinear elements. The goal of the optimization is to increase the speed of evaluation and assembly of large finiteelement matrices on a single GPU (Graphics Processing Unit) while maintaining the accuracy of numerical integration at the desired level. For this reason,...

Fast implementation of FDTDcompatible green's function on multicore processor
PublikacjaIn this letter, numerically efficient implementation of the finitedifference time domain (FDTD)compatible Green's function on a multicore processor is presented. Recently, closedform expression of this discrete Green's function (DGF) was derived, which simplifies its application in the FDTD simulations of radiation and scattering problems. Unfortunately, the new DGF expression involves binomial coefficients, whose computations...

Implementation of FDTDCompatible Green's Function on Graphics Processing Unit
PublikacjaIn this letter, implementation of the finitedifference time domain (FDTD)compatible Green's function on a graphics processing unit (GPU) is presented. Recently, closedform expression for this discrete Green's function (DGF) was derived, which facilitates its applications in the FDTD simulations of radiation and scattering problems. Unfortunately, implementation of the new DGF formula in software requires a multiple precision...

On the approximation of the UWB dipole elliptical arms with steppededge polygon
PublikacjaA simple method of approximation of the ellipticalpatch with steppededge polygon is proposed as an introductionto wider studies over the planar ultrawideband (UWB) antennas.The general idea is to replace the elliptical patch with an equivalentpolygonal patch, with minimum loss in the performance. Theprinciples of the proposed method are presented in this letter, aswell as the results of performed numerical studies and its experimentalverification....
2011

A New Type of MacroElements for Efficient TwoDimensional FEM Analysis
PublikacjaThis letter deals with a model order reduction technique applicable for driven and eigenvalue problems solved using the finite element method (FEM). It allows one to efficiently compute electromagnetic parameters of structures comprising small features that require strong local mesh refinement. The subdomains of very fine mesh are separated from the global domain as so called macroelements that undergo model reduction. The macroelements...

Tuning a Hybrid GPUCPU VCycle Multilevel Preconditioner for Solving Large Real and Complex Systems of FEM Equations
PublikacjaThis letter presents techniques for tuning an accelerated preconditioned conjugate gradient solver with a multilevel preconditioner. The solver is optimized for a fast solution of sparse systems of equations arising in computational electromagnetics in a finite element method using higherorder elements. The goal of the tuning is to increase the throughput while at the same time reducing the memory requirements in order to allow...
2008

Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublikacjaArtykuł przedstawia analizę rozpraszania fali elektromagnetycznej na wielowarstwowych strukturach periodycznych. W analizowanych strukturach zaobserwowano efekt tunelowania fali oraz efekt przestrajania pasm zaporowych/przepustowych (efekt kurtyny elektromagnetycznej)
wyświetlono 85 razy