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Search results for: ANTENNA MODELING
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Zero-Pole Electromagnetic Optimization
PublicationA fast technique for the full-wave optimization of transmission or reflection properties of general linear timeinvariant high-frequency components is proposed. The method is based on the zeros and poles of the rational function representing the scattering parameters of the device being designed and it is the generalization of the technique developed for the design by optimization of microwave filters. The performance of the proposed...
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A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems
PublicationAntennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside...
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Multi-Taper-Based Automatic Correction of Non-Anechoic Antenna Measurements
PublicationPrototype measurements belong to the key steps in the development of antenna structures. Although accurate validation of their far-field performance can be realized in dedicated facilities, such as anechoic chambers, the high cost of their construction and maintenance might not be justified if the main goal of measurements is to support teaching or low-budget research. Instead, they can be performed in non-anechoic conditions and...
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Fast EM-Driven Nature-Inspired Optimization of Antenna Input Characteristics Using Response Features and Variable-Resolution Simulation Models
PublicationUtilization of optimization technique is a must in the design of contemporary antenna systems. Often, global search methods are necessary, which are associated with high computational costs when conducted at the level of full-wave electromagnetic (EM) models. In this study, we introduce an innovative method for globally optimizing reflection responses of multi-band antennas. Our approach uses surrogates constructed based on response...
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The shallow sea experiment with usage of linear hydrophone array
PublicationPurpose of this article is to present designed and made linear hydrophone array and the results obtained during in situ trails on Gulf of Gdańsk. The measuring system allowed to localize hydrophones in the selected points and perform measurements in both the horizontal antenna positioning and vertical. Made in this way recordings allow creating accurate 3D imaging of sound intensity/propagation. During research three floating objects...
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Computationally-efficient design optimisation of antennas by accelerated gradient search with sensitivity and design change monitoring
PublicationElectromagnetic (EM) simulation tools are of primary importance in the design of contemporary antennas. The necessity of accurate performance evaluation of complex structures is a reason why the final tuning of antenna dimensions, aimed at improvement of electrical and field characteristics, needs to be based on EM analysis. Design automation is highly desirable and can be achieved by coupling EM solvers with numerical optimisation...
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Expedited Simulation-Driven Multi-Objective Design Optimization of Quasi-Isotropic Dielectric Resonator Antenna
PublicationMajority of practical engineering design problems require simultaneous handling of several criteria. Although many of design tasks can be turned into single-objective problems using sufficient formulations, in some situations, acquiring comprehensive knowledge about possible trade-offs between conflicting objectives may be necessary. This calls for multi-objective optimization that aims at identifying a set of alternative, Pareto-optimal...
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Recent advances in rapid multiobjective optimization of expensive simulation models in microwave and antenna engineering by Pareto front exploration
PublicationPractical engineering design problems are inherently multiobjective, that is, require simultaneous control of several (and often conflicting) criteria. In many situations, genuine multiobjective optimization is required to acquire comprehensive information about the system of interest. The most popular solution techniques are populationbased metaheuristics, however, they are not practical for handling expensive electromagnetic...
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Domain segmentation for low-cost surrogate-assisted multi-objective design optimisation of antennas
PublicationAbstract: Information regarding the best possible design trade-offs of an antenna structure can be obtained through multiobjective optimisation (MO). Unfortunately, MO is extremely challenging if full-wave electromagnetic (EM) simulation models are used for performance evaluation. Yet, for the majority of contemporary antennas, EM analysis is the only tool that ensures reliability. This study introduces a procedure for accelerated...
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Interactive Application for Visualization of the Basic Phenomena in RF and Microwave Devices
PublicationAn interactive computer application visualizing the basic phenomena in RF and microwave devices is presented. Such kind of educational package can be a very helpful tool for the students as well as for the teachers (of electronics and related fields). This paper is focused on three exemplary problems only and involves: movement of electric charge, filtering of electromagnetic waves and interference phenomena in antenna arrays. The...
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A Review of Antennas for Indoor Positioning Systems
PublicationThis paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of thoseantennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and theirperformance. The described antennas will be subdivided into the following sections according to the nature of measurements:received signal strength (RSS), time of flight (ToF),...
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Filter-Hilbert Method for Automatic Correction of Non-Anechoic Antenna Measurements with Embedded Self-Calibration Mechanism
PublicationOne of the most important steps in the process of antenna development involves measurements of its prototype. Far-field performance of radiators is normally characterized in strictly controlled environments such as anechoic chambers which can ensure certification-grade accuracy. Unfortunately, they are also characterized by high construction costs which might not be justified for low-budget research and/or teaching-related activities....
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Expedited antenna optimization with numerical derivatives and gradient change tracking
PublicationDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
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Highly Miniaturized Self-Diplexed U-Shaped Slot Antenna Based on Shielded QMSIW
PublicationThis article presents an efficient yet simple design approach to highly miniaturized cavity-backed self-diplexing antenna (SDA) with high-isolation. The structure employs a shielded quarter-mode substrate integrated waveguide (QMSIW). Two U-shaped slots are engraved on the top conducting plane, which realize two frequency bands and significant size reduction. The slots are excited by two independent 50Ω orthogonal feed-lines to...
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Impact of Spatial Noise Correlation on Bearing Accuracy in DIFAR Systems
PublicationDIFAR type underwater passive systems are one of the more commonly used tools for detecting submarines. At the design stage, which usually uses computer simulations, it is necessary to generate acoustic noise of the sea. It has been shown that correlating noise significantly reduces these errors compared to the assumption that noise is uncorrelated. In addition, bearing errors have been shown to be the same in systems with a commonly...
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Performance evaluation of GPS anti-spoofing system based on antenna array processing
PublicationThis article concerns the problem of detection and mitigation of spoofing attacks in Global Navigation Satellite Systems. First, background information about spoofing and its possible countermeasures is provided. Next, concept of a novel GPS anti-spoofing system based on antenna array processing is presented and implementation of prototype of this system is described. The third section outlines the performance evaluation of proposed...
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Design and Optimization of Metamaterial-Based Dual-Band 28/38 GHz 5G MIMO Antenna with Modified Ground for Isolation and Bandwidth Improvement
PublicationThis letter presents a high-isolation dual-band multiple-input multiple-output (MIMO) antenna based on the ground plane modification and optimized metamaterials (MMs) for 5G millimeter-wave applications. The antenna is a monopole providing a dual-band response at 5G 28/38 bands with a small physical size (4.8 × 2.9 × 0.762 mm3, excluding the feeding line). The MIMO consists of two symmetric radiating elements arranged adjacently...
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High frequency impulse ground penetrating radar application in assessment of interlayer connections
PublicationGround Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic...
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New Type of Small Broad-Band Internal Antenna for Third Generation Mobile Phone Handsets.
PublicationW pracy przedstawiono nową szerokopasmową antenę łatową przeznaczoną dla telefonów komórkowych trzeciej generacji. Proponowana struktura zawiera obwód (rezonator) w kształcie litery U i zaliczana jest do klasy PIFA (planar inverted-F antenna). W trakcie procesu projektowania przeprowadzono szereg symulacji elektromagnetycznych (metoda momentów), których wyniki zweryfikowano w oparciu o pomiary charakterystyk wykonanego prototypu....
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Pin-on-Substrate Gap Waveguide: An Extremely Low-Cost Realization of High-Performance Gap Waveguide Components
PublicationConsidering the limitations of currently available technologies for the realization of microwave components and antennas, a trade-off between different factors including the efficiency and fabrication cost is required. The main objective of this letter is to propose a novel method for the realization of gap waveguides (GWGs) that take advantage of conventional PCB fabrication technology, thus are low cost and light weight. Moreover,...
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An Improvement of Global Complex Roots and Poles Finding Algorithm for Propagation and Radiation Problems
PublicationAn improvement of the recently developed global roots finding algorithm has been proposed. The modification allows to shorten the computational time by reducing the number of function calls. Moreover, both versions of the algorithms (standard and modified) have been tested for numerically defined functions obtained from spectral domain approach and field matching method. The tests have been performed for three simple microwave...
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High-precision bearing estimation for active sonar with cylindrical array performed by interpolated array transformation
PublicationThe article presents a method for improving the accuracy of bearing in multibeam sonar with a cylindrical array. The antenna’s non-linear shape and the resulting non-uniform sampling of the signal in space, mean that known methods of high-resolution spectral analysis cannot be used. In order to apply an algorithm from this group, a linear virtual antenna must be produced. The paper presents a technique of mapping a cylindrical...
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A structure and design of a novel compact UWB MIMO antenna
PublicationIn the paper, a concept and design procedure of a novel compact MIMO slot antenna is presented. In order to achieve a better filling of available space, individual antennas are constrained to a triangular shape and optimized for a reduced size. The MIMO structure is then assembled using the two of previously designed antennas in orthogonal arrangement. Surrogate-assisted numerical optimization involving variable-fidelity electromagnetic...
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Jacobi and gauss-seidel preconditioned complex conjugate gradient method with GPU acceleration for finite element method
PublicationIn this paper two implementations of iterative solvers for solving complex symmetric and sparse systems resulting from finite element method applied to wave equation are discussed. The problem under investigation is a dielectric resonator antenna (DRA) discretized by FEM with vector elements of the second order (LT/QN). The solvers use the preconditioned conjugate gradient (pcg) method implemented on Graphics Processing Unit (GPU)...
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Application of gpr method in diagnostics of reinforced concrete structures
PublicationThis paper presents an application of the ground penetration method (GPR) for diagnostics of reinforced concrete structures. In situ measurements were conducted for three civil engineering structures: the ground floor structure, the abutment of the railway viaduct and the concrete well. The dual polarized ground penetrating radar with the antenna operating at a center frequency of 2 GHz was used for GPR surveys. Three different...
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RSS-Based DoA Estimation Using ESPAR Antenna for V2X Applications in 802.11p Frequency Band
PublicationIn 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 be also used for DoA estimation....
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Wideband Off-Body Channel Characteristics with Dynamic User
PublicationThis paper presents the preliminary results of a dynamic off-body channel characterisation study, based on wideband measurements at 5.8 GHz in an indoor environment. The Channel Impulse Response (CIR) was measured for a scenario with the user approaching and departing from the off-body antenna. A CIR deconvolution procedure was performed jointly in two polarisations, and the received signal power, Cross-Polarisation Discrimination...
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Magnetic field mapping along a NV-rich nanodiamond-doped fiber
PublicationIntegration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows...
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Reduced-Cost Design Optimization of High-Frequency Structures Using Adaptive Jacobian Updates
PublicationElectromagnetic (EM) analysis is the primary tool utilized in the design of high-frequency structures. In vast majority of cases, simpler models (e.g., equivalent networks or analytical ones) are either not available or lack accuracy: they can only be used to yield initial designs that need to be further tuned. Consequently, EM-driven adjustment of geometry and/or material parameters of microwave and antenna components is a necessary...
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A Low-Cost System for Far-Field Non-Anechoic Measurements of Antenna Performance Figures
PublicationPrototype measurements are the key step in the development of antenna structures. Typically, their far-field characteristics are validated in expensive, dedicated facilities such as open range sites, or anechoic chambers. Despite being necessary for obtaining high-precision data (e.g., for device qualification), the use of costly infrastructure might not be fully justified when the main goal of measurements includes demonstration...
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Noise Analysis of Continuous GPS Time Series of Selected EPN Stations to Investigate Variations in Stability of Monument Types
PublicationThe type of monument that a GPS antenna is placed on plays a significant role in noise estimation for each permanent GPS station. In this research 18 Polish permanent GPS stations that belong to the EPN (EUREF Permanent Network) were analyzed using Maximum Likelihood Estimation (MLE). The antennae of Polish EPN stations are placed on roofs of buildings or on concrete pillars. The analyzed data covers a period of 5 years from 2008...
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Frequency Selective Surface Based MIMO Antenna Array for 5G Millimeter-Wave Applications
PublicationAbstract: In this paper a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2×2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabri-cated on Rogers RT/Duroid high frequency substrate...
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System Loss Model for Body-to-Body Networks in Indoor and Outdoor Environments
PublicationA system loss model for body-to-body networks in indoor and outdoor environments is proposed in this paper, based on measurements taken at 2.45 GHz. The influence of the type of environment, antenna visibility and user mobility on model parameters has been investigated. A significant impact of mutual antennas’ placement and their visibility is shown. The proposed model fits well to empirical data, with the average root mean square...
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UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA
PublicationStudy of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...
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Diver Observations by Means of Acoustic Methods
PublicationSearching for objects, especially small ones, moving under water near its the free surface, is always not an easy task. Designing tools for the detection of such targets is a real challenge when the possibility of a terrorist attack is a real threat. This paper presents some aspects of diver detection by means of acoustics methods, both active (side scan sonar) and passive ones (linear receiving antenna). This approach is quite...
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Design of microstrip antenna subarrays: a simulation-driven surrogate-based approach
PublicationA methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (here, a corporate network) on the subarray side-lobe level and allows adjustment of both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces...
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Simulation-Driven Design of Microstrip Antenna Subarrays
PublicationA methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (e.g., a corporate network) on the subarray side lobe level and allows adjusting both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based optimization that produces designs...
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A system for Direction-Of-Arrival estimation in ISM 2.4 GHz frequency band based on ESPAR antenna and SDR technology
PublicationDetermination of the direction of the signal arrival (DOA) finds many applications in various areas of science and industry. Knowledge of DOA is used, among others to determine the position of a satellite with a low Earth orbit (LEO), localization of people and things as well as in research of wireless communication systems, for instance the determination of the number of...
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An Analysis of Elliptical-Rectangular Multipatch Structure on Dielectric-Coated Confocal and Nonconfocal Elliptic Cylinders
PublicationA rigorous analysis of the resonance frequency problem of an elliptical-rectangular microstrip structure mounted on dielectric-coated elliptic conducting cylinder, with electrically small radius, is investigated in this paper. A full-wave analysis and a moment-method calculation are employed. The analysis is carried out considering the expansion of the field as a series of Mathieu functions. The complex resonance frequencies of...
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Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system
PublicationIt is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of...
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Resonance Frequency Calculation of a Multilayer and Multipatch Spherical Microstrip Structure Using a Hybrid Technique
PublicationThis communication offers a rigorous analysis of the resonance frequency problem of a spherical microstrip structure mounted on a multilayer, dielectric-coated metallic sphere, with an electrically small radius. The structure consists of single or multiple metallic patches with arbitrary shapes. A full-wave analysis is employed with the use of proposed hybrid approach, combining the finite-difference technique with a spectral domain...
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Self-assemblies of novel magnesium porphyrins mimicking natural chlorosomal bacteriochlorophylls
PublicationSelf-assembling porphyrins are promising materials to mimic natural bacteriochlorophylls c, d, or e encountered in the chlorosomes of photosynthetic bacteria. We have studied four novel magnesium porphyrins mimicking this chlorosomal antenna system. In contrast to previous articles reporting synthetic Zn-porphyrins, our studies focus on porphyrins with Mg as the central atom, which mimic more closely the natural bacteriochlorophylls....
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Depolarisation Model for a BAN Indoor Scenario
PublicationIn this paper, an analysis of depolarisation in Body Area Networks for Body-to-Infrastructure communications based on a measurement campaign in the 5.8 GHz band in an indoor environment is performed. Measurements were made with an offbody antenna transmitting linearly polarised signals and dualpolarised receiving antennas carried by the user on the body. A Normal Distribution with a mean of 2.0 dB and a standard deviation of 4.3...
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Fast Calibration-Free Single-Anchor Indoor Localization Based on Limited Number of ESPAR Antenna Radiation Patterns
Publication— In this article, we investigate how the calibrationfree single-anchor indoor localization algorithm developed for base stations equipped with electronically steerable parasitic array radiator (ESPAR) antennas can further be improved. By reducing the total number of ESPAR antenna radiation patterns used in localization process, one can significantly reduce the time needed for an object localization. Performed localization measurements...
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Assessment of User Mobility’s Influence on System Loss in Several Body-to-Body Scenarios
PublicationIn this paper, Body-to-Body communications in indoor and outdoor environments for different on-body antenna configurations and different mobility scenarios were studied, based on system loss measurements at 2.45 GHz. The main objective is to properly characterise the influence of the Transmitter-Receiver configuration on system loss and fast fading behaviour, the latter being modelled by the Rice Distribution. Globally, it is observed...
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Linear antenna microwave chemical vapour deposition of diamond films on long-period fiber gratings for bio-sensing applications
PublicationThe growth processes of nanocrystalline diamond (NCD) thin films on fused silica optical fibers with UV-induced long-period gratings (LPGs) were investigated with regard to biosensing applications. The films were deposited using a linear antenna microwave plasma enhanced chemical vapor deposition system, which allows for the growth of diamond at temperatures below 350°C. The films exhibited a high refractive index n = 2.32, as...
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DoA Estimation Using Reconfigurable Antennas in Millimiter-Wave Frequency 5G Systems
PublicationTo achieve low latency and high throughputs, future 5G systems will have to utilize complex antenna systems able to provide beamforming and direction-of-arrival (DoA) estimation capabilities. Most of the concepts available in the literature rely on analog or digital beamforming, which is well developed and can be used both at a base station and in a user terminal. However, in applications, in which...
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Multi-objective antenna design by means of sequential domain patching
PublicationA 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 stencil-based search that aims at creating a path that connects the extreme Pareto-optimal designs, obtained by means of single-objective optimization runs. The patching process yields the initial approximation of the...
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Analysis of radiation and scattering problems with the use of hybrid techniques based on the discrete Green's function formulation of the FDTD method
PublicationIn this contribution, simulation scenarios are presented which take advantage of the hybrid techniques based on the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method. DGF-FDTD solutions are compatible with the finite-difference grid and can be applied for perfect hybridization of the FDTD method. The following techniques are considered: (i) DGF-FDTD for antenna simulations, (ii) DGF-based...
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System Loss Model for Body Area Networks in Room Scenarios
PublicationThis paper presents an analysis of system loss in Body Area Networks for room scenarios, based on a wideband measurement campaign at 5.8 GHz. The measurements were performed with a fixed antenna transmitting vertically and horizontally polarised signals, while the user wears dualpolarised antennas. The average system losses in co- and crosspolarised channels are 41.4 and 42.6 dB for vertically polarised transmitted signals and...